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zig/src/arch/wasm/CodeGen.zig
Luuk de Gram 63c25cc1cc wasm: fix callInstrinsic return value 
Rather than storing it in a local and returning that,
we now keep this on the stack as all internal functions
expect it to be on the stack already and therefore were
generating extra `local.set` instructions.
2022-08-18 14:17:01 +02:00

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const std = @import("std");
const Allocator = std.mem.Allocator;
const ArrayList = std.ArrayList;
const assert = std.debug.assert;
const testing = std.testing;
const leb = std.leb;
const mem = std.mem;
const wasm = std.wasm;
const log = std.log.scoped(.codegen);
const codegen = @import("../../codegen.zig");
const Module = @import("../../Module.zig");
const Decl = Module.Decl;
const Type = @import("../../type.zig").Type;
const Value = @import("../../value.zig").Value;
const Compilation = @import("../../Compilation.zig");
const LazySrcLoc = Module.LazySrcLoc;
const link = @import("../../link.zig");
const TypedValue = @import("../../TypedValue.zig");
const Air = @import("../../Air.zig");
const Liveness = @import("../../Liveness.zig");
const Mir = @import("Mir.zig");
const Emit = @import("Emit.zig");
const abi = @import("abi.zig");
const errUnionPayloadOffset = codegen.errUnionPayloadOffset;
const errUnionErrorOffset = codegen.errUnionErrorOffset;
/// Wasm Value, created when generating an instruction
const WValue = union(enum) {
/// May be referenced but is unused
none: void,
/// The value lives on top of the stack
stack: void,
/// Index of the local variable
local: u32,
/// An immediate 32bit value
imm32: u32,
/// An immediate 64bit value
imm64: u64,
/// A constant 32bit float value
float32: f32,
/// A constant 64bit float value
float64: f64,
/// A value that represents a pointer to the data section
/// Note: The value contains the symbol index, rather than the actual address
/// as we use this to perform the relocation.
memory: u32,
/// A value that represents a parent pointer and an offset
/// from that pointer. i.e. when slicing with constant values.
memory_offset: struct {
/// The symbol of the parent pointer
pointer: u32,
/// Offset will be set as addend when relocating
offset: u32,
},
/// Represents a function pointer
/// In wasm function pointers are indexes into a function table,
/// rather than an address in the data section.
function_index: u32,
/// Offset from the bottom of the virtual stack, with the offset
/// pointing to where the value lives.
stack_offset: u32,
/// Returns the offset from the bottom of the stack. This is useful when
/// we use the load or store instruction to ensure we retrieve the value
/// from the correct position, rather than the value that lives at the
/// bottom of the stack. For instances where `WValue` is not `stack_value`
/// this will return 0, which allows us to simply call this function for all
/// loads and stores without requiring checks everywhere.
fn offset(self: WValue) u32 {
switch (self) {
.stack_offset => |stack_offset| return stack_offset,
else => return 0,
}
}
/// Promotes a `WValue` to a local when given value is on top of the stack.
/// When encountering a `local` or `stack_offset` this is essentially a no-op.
/// All other tags are illegal.
fn toLocal(value: WValue, gen: *Self, ty: Type) InnerError!WValue {
switch (value) {
.stack => {
const local = try gen.allocLocal(ty);
try gen.addLabel(.local_set, local.local);
return local;
},
.local, .stack_offset => return value,
else => unreachable,
}
}
/// Marks a local as no longer being referenced and essentially allows
/// us to re-use it somewhere else within the function.
/// The valtype of the local is deducted by using the index of the given.
fn free(value: *WValue, gen: *Self) void {
if (value.* != .local) return;
const local_value = value.local;
const index = local_value - gen.args.len - @boolToInt(gen.return_value != .none);
const valtype = @intToEnum(wasm.Valtype, gen.locals.items[index]);
switch (valtype) {
.i32 => gen.free_locals_i32.append(gen.gpa, local_value) catch return, // It's ok to fail any of those, a new local can be allocated instead
.i64 => gen.free_locals_i64.append(gen.gpa, local_value) catch return,
.f32 => gen.free_locals_f32.append(gen.gpa, local_value) catch return,
.f64 => gen.free_locals_f64.append(gen.gpa, local_value) catch return,
}
value.* = WValue{ .none = {} };
}
};
/// Wasm ops, but without input/output/signedness information
/// Used for `buildOpcode`
const Op = enum {
@"unreachable",
nop,
block,
loop,
@"if",
@"else",
end,
br,
br_if,
br_table,
@"return",
call,
call_indirect,
drop,
select,
local_get,
local_set,
local_tee,
global_get,
global_set,
load,
store,
memory_size,
memory_grow,
@"const",
eqz,
eq,
ne,
lt,
gt,
le,
ge,
clz,
ctz,
popcnt,
add,
sub,
mul,
div,
rem,
@"and",
@"or",
xor,
shl,
shr,
rotl,
rotr,
abs,
neg,
ceil,
floor,
trunc,
nearest,
sqrt,
min,
max,
copysign,
wrap,
convert,
demote,
promote,
reinterpret,
extend,
};
/// Contains the settings needed to create an `Opcode` using `buildOpcode`.
///
/// The fields correspond to the opcode name. Here is an example
/// i32_trunc_f32_s
/// ^ ^ ^ ^
/// | | | |
/// valtype1 | | |
/// = .i32 | | |
/// | | |
/// op | |
/// = .trunc | |
/// | |
/// valtype2 |
/// = .f32 |
/// |
/// width |
/// = null |
/// |
/// signed
/// = true
///
/// There can be missing fields, here are some more examples:
/// i64_load8_u
/// --> .{ .valtype1 = .i64, .op = .load, .width = 8, signed = false }
/// i32_mul
/// --> .{ .valtype1 = .i32, .op = .trunc }
/// nop
/// --> .{ .op = .nop }
const OpcodeBuildArguments = struct {
/// First valtype in the opcode (usually represents the type of the output)
valtype1: ?wasm.Valtype = null,
/// The operation (e.g. call, unreachable, div, min, sqrt, etc.)
op: Op,
/// Width of the operation (e.g. 8 for i32_load8_s, 16 for i64_extend16_i32_s)
width: ?u8 = null,
/// Second valtype in the opcode name (usually represents the type of the input)
valtype2: ?wasm.Valtype = null,
/// Signedness of the op
signedness: ?std.builtin.Signedness = null,
};
/// Helper function that builds an Opcode given the arguments needed
fn buildOpcode(args: OpcodeBuildArguments) wasm.Opcode {
switch (args.op) {
.@"unreachable" => return .@"unreachable",
.nop => return .nop,
.block => return .block,
.loop => return .loop,
.@"if" => return .@"if",
.@"else" => return .@"else",
.end => return .end,
.br => return .br,
.br_if => return .br_if,
.br_table => return .br_table,
.@"return" => return .@"return",
.call => return .call,
.call_indirect => return .call_indirect,
.drop => return .drop,
.select => return .select,
.local_get => return .local_get,
.local_set => return .local_set,
.local_tee => return .local_tee,
.global_get => return .global_get,
.global_set => return .global_set,
.load => if (args.width) |width| switch (width) {
8 => switch (args.valtype1.?) {
.i32 => if (args.signedness.? == .signed) return .i32_load8_s else return .i32_load8_u,
.i64 => if (args.signedness.? == .signed) return .i64_load8_s else return .i64_load8_u,
.f32, .f64 => unreachable,
},
16 => switch (args.valtype1.?) {
.i32 => if (args.signedness.? == .signed) return .i32_load16_s else return .i32_load16_u,
.i64 => if (args.signedness.? == .signed) return .i64_load16_s else return .i64_load16_u,
.f32, .f64 => unreachable,
},
32 => switch (args.valtype1.?) {
.i64 => if (args.signedness.? == .signed) return .i64_load32_s else return .i64_load32_u,
.i32 => return .i32_load,
.f32 => return .f32_load,
.f64 => unreachable,
},
64 => switch (args.valtype1.?) {
.i64 => return .i64_load,
.f64 => return .f64_load,
else => unreachable,
},
else => unreachable,
} else switch (args.valtype1.?) {
.i32 => return .i32_load,
.i64 => return .i64_load,
.f32 => return .f32_load,
.f64 => return .f64_load,
},
.store => if (args.width) |width| {
switch (width) {
8 => switch (args.valtype1.?) {
.i32 => return .i32_store8,
.i64 => return .i64_store8,
.f32, .f64 => unreachable,
},
16 => switch (args.valtype1.?) {
.i32 => return .i32_store16,
.i64 => return .i64_store16,
.f32, .f64 => unreachable,
},
32 => switch (args.valtype1.?) {
.i64 => return .i64_store32,
.i32 => return .i32_store,
.f32 => return .f32_store,
.f64 => unreachable,
},
64 => switch (args.valtype1.?) {
.i64 => return .i64_store,
.f64 => return .f64_store,
else => unreachable,
},
else => unreachable,
}
} else {
switch (args.valtype1.?) {
.i32 => return .i32_store,
.i64 => return .i64_store,
.f32 => return .f32_store,
.f64 => return .f64_store,
}
},
.memory_size => return .memory_size,
.memory_grow => return .memory_grow,
.@"const" => switch (args.valtype1.?) {
.i32 => return .i32_const,
.i64 => return .i64_const,
.f32 => return .f32_const,
.f64 => return .f64_const,
},
.eqz => switch (args.valtype1.?) {
.i32 => return .i32_eqz,
.i64 => return .i64_eqz,
.f32, .f64 => unreachable,
},
.eq => switch (args.valtype1.?) {
.i32 => return .i32_eq,
.i64 => return .i64_eq,
.f32 => return .f32_eq,
.f64 => return .f64_eq,
},
.ne => switch (args.valtype1.?) {
.i32 => return .i32_ne,
.i64 => return .i64_ne,
.f32 => return .f32_ne,
.f64 => return .f64_ne,
},
.lt => switch (args.valtype1.?) {
.i32 => if (args.signedness.? == .signed) return .i32_lt_s else return .i32_lt_u,
.i64 => if (args.signedness.? == .signed) return .i64_lt_s else return .i64_lt_u,
.f32 => return .f32_lt,
.f64 => return .f64_lt,
},
.gt => switch (args.valtype1.?) {
.i32 => if (args.signedness.? == .signed) return .i32_gt_s else return .i32_gt_u,
.i64 => if (args.signedness.? == .signed) return .i64_gt_s else return .i64_gt_u,
.f32 => return .f32_gt,
.f64 => return .f64_gt,
},
.le => switch (args.valtype1.?) {
.i32 => if (args.signedness.? == .signed) return .i32_le_s else return .i32_le_u,
.i64 => if (args.signedness.? == .signed) return .i64_le_s else return .i64_le_u,
.f32 => return .f32_le,
.f64 => return .f64_le,
},
.ge => switch (args.valtype1.?) {
.i32 => if (args.signedness.? == .signed) return .i32_ge_s else return .i32_ge_u,
.i64 => if (args.signedness.? == .signed) return .i64_ge_s else return .i64_ge_u,
.f32 => return .f32_ge,
.f64 => return .f64_ge,
},
.clz => switch (args.valtype1.?) {
.i32 => return .i32_clz,
.i64 => return .i64_clz,
.f32, .f64 => unreachable,
},
.ctz => switch (args.valtype1.?) {
.i32 => return .i32_ctz,
.i64 => return .i64_ctz,
.f32, .f64 => unreachable,
},
.popcnt => switch (args.valtype1.?) {
.i32 => return .i32_popcnt,
.i64 => return .i64_popcnt,
.f32, .f64 => unreachable,
},
.add => switch (args.valtype1.?) {
.i32 => return .i32_add,
.i64 => return .i64_add,
.f32 => return .f32_add,
.f64 => return .f64_add,
},
.sub => switch (args.valtype1.?) {
.i32 => return .i32_sub,
.i64 => return .i64_sub,
.f32 => return .f32_sub,
.f64 => return .f64_sub,
},
.mul => switch (args.valtype1.?) {
.i32 => return .i32_mul,
.i64 => return .i64_mul,
.f32 => return .f32_mul,
.f64 => return .f64_mul,
},
.div => switch (args.valtype1.?) {
.i32 => if (args.signedness.? == .signed) return .i32_div_s else return .i32_div_u,
.i64 => if (args.signedness.? == .signed) return .i64_div_s else return .i64_div_u,
.f32 => return .f32_div,
.f64 => return .f64_div,
},
.rem => switch (args.valtype1.?) {
.i32 => if (args.signedness.? == .signed) return .i32_rem_s else return .i32_rem_u,
.i64 => if (args.signedness.? == .signed) return .i64_rem_s else return .i64_rem_u,
.f32, .f64 => unreachable,
},
.@"and" => switch (args.valtype1.?) {
.i32 => return .i32_and,
.i64 => return .i64_and,
.f32, .f64 => unreachable,
},
.@"or" => switch (args.valtype1.?) {
.i32 => return .i32_or,
.i64 => return .i64_or,
.f32, .f64 => unreachable,
},
.xor => switch (args.valtype1.?) {
.i32 => return .i32_xor,
.i64 => return .i64_xor,
.f32, .f64 => unreachable,
},
.shl => switch (args.valtype1.?) {
.i32 => return .i32_shl,
.i64 => return .i64_shl,
.f32, .f64 => unreachable,
},
.shr => switch (args.valtype1.?) {
.i32 => if (args.signedness.? == .signed) return .i32_shr_s else return .i32_shr_u,
.i64 => if (args.signedness.? == .signed) return .i64_shr_s else return .i64_shr_u,
.f32, .f64 => unreachable,
},
.rotl => switch (args.valtype1.?) {
.i32 => return .i32_rotl,
.i64 => return .i64_rotl,
.f32, .f64 => unreachable,
},
.rotr => switch (args.valtype1.?) {
.i32 => return .i32_rotr,
.i64 => return .i64_rotr,
.f32, .f64 => unreachable,
},
.abs => switch (args.valtype1.?) {
.i32, .i64 => unreachable,
.f32 => return .f32_abs,
.f64 => return .f64_abs,
},
.neg => switch (args.valtype1.?) {
.i32, .i64 => unreachable,
.f32 => return .f32_neg,
.f64 => return .f64_neg,
},
.ceil => switch (args.valtype1.?) {
.i64 => unreachable,
.i32 => return .f32_ceil, // when valtype is f16, we store it in i32.
.f32 => return .f32_ceil,
.f64 => return .f64_ceil,
},
.floor => switch (args.valtype1.?) {
.i64 => unreachable,
.i32 => return .f32_floor, // when valtype is f16, we store it in i32.
.f32 => return .f32_floor,
.f64 => return .f64_floor,
},
.trunc => switch (args.valtype1.?) {
.i32 => if (args.valtype2) |valty| switch (valty) {
.i32 => unreachable,
.i64 => unreachable,
.f32 => if (args.signedness.? == .signed) return .i32_trunc_f32_s else return .i32_trunc_f32_u,
.f64 => if (args.signedness.? == .signed) return .i32_trunc_f64_s else return .i32_trunc_f64_u,
} else return .f32_trunc, // when no valtype2, it's an f16 instead which is stored in an i32.
.i64 => unreachable,
.f32 => return .f32_trunc,
.f64 => return .f64_trunc,
},
.nearest => switch (args.valtype1.?) {
.i32, .i64 => unreachable,
.f32 => return .f32_nearest,
.f64 => return .f64_nearest,
},
.sqrt => switch (args.valtype1.?) {
.i32, .i64 => unreachable,
.f32 => return .f32_sqrt,
.f64 => return .f64_sqrt,
},
.min => switch (args.valtype1.?) {
.i32, .i64 => unreachable,
.f32 => return .f32_min,
.f64 => return .f64_min,
},
.max => switch (args.valtype1.?) {
.i32, .i64 => unreachable,
.f32 => return .f32_max,
.f64 => return .f64_max,
},
.copysign => switch (args.valtype1.?) {
.i32, .i64 => unreachable,
.f32 => return .f32_copysign,
.f64 => return .f64_copysign,
},
.wrap => switch (args.valtype1.?) {
.i32 => switch (args.valtype2.?) {
.i32 => unreachable,
.i64 => return .i32_wrap_i64,
.f32, .f64 => unreachable,
},
.i64, .f32, .f64 => unreachable,
},
.convert => switch (args.valtype1.?) {
.i32, .i64 => unreachable,
.f32 => switch (args.valtype2.?) {
.i32 => if (args.signedness.? == .signed) return .f32_convert_i32_s else return .f32_convert_i32_u,
.i64 => if (args.signedness.? == .signed) return .f32_convert_i64_s else return .f32_convert_i64_u,
.f32, .f64 => unreachable,
},
.f64 => switch (args.valtype2.?) {
.i32 => if (args.signedness.? == .signed) return .f64_convert_i32_s else return .f64_convert_i32_u,
.i64 => if (args.signedness.? == .signed) return .f64_convert_i64_s else return .f64_convert_i64_u,
.f32, .f64 => unreachable,
},
},
.demote => if (args.valtype1.? == .f32 and args.valtype2.? == .f64) return .f32_demote_f64 else unreachable,
.promote => if (args.valtype1.? == .f64 and args.valtype2.? == .f32) return .f64_promote_f32 else unreachable,
.reinterpret => switch (args.valtype1.?) {
.i32 => if (args.valtype2.? == .f32) return .i32_reinterpret_f32 else unreachable,
.i64 => if (args.valtype2.? == .f64) return .i64_reinterpret_f64 else unreachable,
.f32 => if (args.valtype2.? == .i32) return .f32_reinterpret_i32 else unreachable,
.f64 => if (args.valtype2.? == .i64) return .f64_reinterpret_i64 else unreachable,
},
.extend => switch (args.valtype1.?) {
.i32 => switch (args.width.?) {
8 => if (args.signedness.? == .signed) return .i32_extend8_s else unreachable,
16 => if (args.signedness.? == .signed) return .i32_extend16_s else unreachable,
else => unreachable,
},
.i64 => switch (args.width.?) {
8 => if (args.signedness.? == .signed) return .i64_extend8_s else unreachable,
16 => if (args.signedness.? == .signed) return .i64_extend16_s else unreachable,
32 => if (args.signedness.? == .signed) return .i64_extend32_s else unreachable,
else => unreachable,
},
.f32, .f64 => unreachable,
},
}
}
test "Wasm - buildOpcode" {
// Make sure buildOpcode is referenced, and test some examples
const i32_const = buildOpcode(.{ .op = .@"const", .valtype1 = .i32 });
const end = buildOpcode(.{ .op = .end });
const local_get = buildOpcode(.{ .op = .local_get });
const i64_extend32_s = buildOpcode(.{ .op = .extend, .valtype1 = .i64, .width = 32, .signedness = .signed });
const f64_reinterpret_i64 = buildOpcode(.{ .op = .reinterpret, .valtype1 = .f64, .valtype2 = .i64 });
try testing.expectEqual(@as(wasm.Opcode, .i32_const), i32_const);
try testing.expectEqual(@as(wasm.Opcode, .end), end);
try testing.expectEqual(@as(wasm.Opcode, .local_get), local_get);
try testing.expectEqual(@as(wasm.Opcode, .i64_extend32_s), i64_extend32_s);
try testing.expectEqual(@as(wasm.Opcode, .f64_reinterpret_i64), f64_reinterpret_i64);
}
pub const Result = union(enum) {
/// The codegen bytes have been appended to `Context.code`
appended: void,
/// The data is managed externally and are part of the `Result`
externally_managed: []const u8,
};
/// Hashmap to store generated `WValue` for each `Air.Inst.Ref`
pub const ValueTable = std.AutoHashMapUnmanaged(Air.Inst.Ref, WValue);
const Self = @This();
/// Reference to the function declaration the code
/// section belongs to
decl: *Decl,
decl_index: Decl.Index,
/// Current block depth. Used to calculate the relative difference between a break
/// and block
block_depth: u32 = 0,
air: Air,
liveness: Liveness,
gpa: mem.Allocator,
debug_output: codegen.DebugInfoOutput,
mod_fn: *const Module.Fn,
/// Table to save `WValue`'s generated by an `Air.Inst`
values: ValueTable,
/// Mapping from Air.Inst.Index to block ids
blocks: std.AutoArrayHashMapUnmanaged(Air.Inst.Index, struct {
label: u32,
value: WValue,
}) = .{},
/// `bytes` contains the wasm bytecode belonging to the 'code' section.
code: *ArrayList(u8),
/// The index the next local generated will have
/// NOTE: arguments share the index with locals therefore the first variable
/// will have the index that comes after the last argument's index
local_index: u32 = 0,
/// The index of the current argument.
/// Used to track which argument is being referenced in `airArg`.
arg_index: u32 = 0,
/// If codegen fails, an error messages will be allocated and saved in `err_msg`
err_msg: *Module.ErrorMsg,
/// List of all locals' types generated throughout this declaration
/// used to emit locals count at start of 'code' section.
locals: std.ArrayListUnmanaged(u8),
/// The Target we're emitting (used to call intInfo)
target: std.Target,
/// Represents the wasm binary file that is being linked.
bin_file: *link.File.Wasm,
/// List of MIR Instructions
mir_instructions: std.MultiArrayList(Mir.Inst) = .{},
/// Contains extra data for MIR
mir_extra: std.ArrayListUnmanaged(u32) = .{},
/// When a function is executing, we store the the current stack pointer's value within this local.
/// This value is then used to restore the stack pointer to the original value at the return of the function.
initial_stack_value: WValue = .none,
/// The current stack pointer substracted with the stack size. From this value, we will calculate
/// all offsets of the stack values.
bottom_stack_value: WValue = .none,
/// Arguments of this function declaration
/// This will be set after `resolveCallingConventionValues`
args: []WValue = &.{},
/// This will only be `.none` if the function returns void, or returns an immediate.
/// When it returns a pointer to the stack, the `.local` tag will be active and must be populated
/// before this function returns its execution to the caller.
return_value: WValue = .none,
/// The size of the stack this function occupies. In the function prologue
/// we will move the stack pointer by this number, forward aligned with the `stack_alignment`.
stack_size: u32 = 0,
/// The stack alignment, which is 16 bytes by default. This is specified by the
/// tool-conventions: https://github.com/WebAssembly/tool-conventions/blob/main/BasicCABI.md
/// and also what the llvm backend will emit.
/// However, local variables or the usage of `@setAlignStack` can overwrite this default.
stack_alignment: u32 = 16,
// For each individual Wasm valtype we store a seperate free list which
// allows us to re-use locals that are no longer used. e.g. a temporary local.
/// A list of indexes which represents a local of valtype `i32`.
/// It is illegal to store a non-i32 valtype in this list.
free_locals_i32: std.ArrayListUnmanaged(u32) = .{},
/// A list of indexes which represents a local of valtype `i64`.
/// It is illegal to store a non-i32 valtype in this list.
free_locals_i64: std.ArrayListUnmanaged(u32) = .{},
/// A list of indexes which represents a local of valtype `f32`.
/// It is illegal to store a non-i32 valtype in this list.
free_locals_f32: std.ArrayListUnmanaged(u32) = .{},
/// A list of indexes which represents a local of valtype `f64`.
/// It is illegal to store a non-i32 valtype in this list.
free_locals_f64: std.ArrayListUnmanaged(u32) = .{},
const InnerError = error{
OutOfMemory,
/// An error occurred when trying to lower AIR to MIR.
CodegenFail,
/// Can occur when dereferencing a pointer that points to a `Decl` of which the analysis has failed
AnalysisFail,
/// Compiler implementation could not handle a large integer.
Overflow,
};
pub fn deinit(self: *Self) void {
self.values.deinit(self.gpa);
self.blocks.deinit(self.gpa);
self.locals.deinit(self.gpa);
self.mir_instructions.deinit(self.gpa);
self.mir_extra.deinit(self.gpa);
self.* = undefined;
}
/// Sets `err_msg` on `CodeGen` and returns `error.CodegenFail` which is caught in link/Wasm.zig
fn fail(self: *Self, comptime fmt: []const u8, args: anytype) InnerError {
const src = LazySrcLoc.nodeOffset(0);
const src_loc = src.toSrcLoc(self.decl);
self.err_msg = try Module.ErrorMsg.create(self.gpa, src_loc, fmt, args);
return error.CodegenFail;
}
/// Resolves the `WValue` for the given instruction `inst`
/// When the given instruction has a `Value`, it returns a constant instead
fn resolveInst(self: *Self, ref: Air.Inst.Ref) InnerError!WValue {
const gop = try self.values.getOrPut(self.gpa, ref);
if (gop.found_existing) return gop.value_ptr.*;
// when we did not find an existing instruction, it
// means we must generate it from a constant.
const val = self.air.value(ref).?;
const ty = self.air.typeOf(ref);
if (!ty.hasRuntimeBitsIgnoreComptime() and !ty.isInt() and !ty.isError()) {
gop.value_ptr.* = WValue{ .none = {} };
return gop.value_ptr.*;
}
// When we need to pass the value by reference (such as a struct), we will
// leverage `generateSymbol` to lower the constant to bytes and emit it
// to the 'rodata' section. We then return the index into the section as `WValue`.
//
// In the other cases, we will simply lower the constant to a value that fits
// into a single local (such as a pointer, integer, bool, etc).
const result = if (isByRef(ty, self.target)) blk: {
const sym_index = try self.bin_file.lowerUnnamedConst(.{ .ty = ty, .val = val }, self.decl_index);
break :blk WValue{ .memory = sym_index };
} else try self.lowerConstant(val, ty);
gop.value_ptr.* = result;
return result;
}
/// Appends a MIR instruction and returns its index within the list of instructions
fn addInst(self: *Self, inst: Mir.Inst) error{OutOfMemory}!void {
try self.mir_instructions.append(self.gpa, inst);
}
fn addTag(self: *Self, tag: Mir.Inst.Tag) error{OutOfMemory}!void {
try self.addInst(.{ .tag = tag, .data = .{ .tag = {} } });
}
fn addExtended(self: *Self, opcode: wasm.PrefixedOpcode) error{OutOfMemory}!void {
try self.addInst(.{ .tag = .extended, .secondary = @enumToInt(opcode), .data = .{ .tag = {} } });
}
fn addLabel(self: *Self, tag: Mir.Inst.Tag, label: u32) error{OutOfMemory}!void {
try self.addInst(.{ .tag = tag, .data = .{ .label = label } });
}
fn addImm32(self: *Self, imm: i32) error{OutOfMemory}!void {
try self.addInst(.{ .tag = .i32_const, .data = .{ .imm32 = imm } });
}
/// Accepts an unsigned 64bit integer rather than a signed integer to
/// prevent us from having to bitcast multiple times as most values
/// within codegen are represented as unsigned rather than signed.
fn addImm64(self: *Self, imm: u64) error{OutOfMemory}!void {
const extra_index = try self.addExtra(Mir.Imm64.fromU64(imm));
try self.addInst(.{ .tag = .i64_const, .data = .{ .payload = extra_index } });
}
fn addFloat64(self: *Self, float: f64) error{OutOfMemory}!void {
const extra_index = try self.addExtra(Mir.Float64.fromFloat64(float));
try self.addInst(.{ .tag = .f64_const, .data = .{ .payload = extra_index } });
}
/// Inserts an instruction to load/store from/to wasm's linear memory dependent on the given `tag`.
fn addMemArg(self: *Self, tag: Mir.Inst.Tag, mem_arg: Mir.MemArg) error{OutOfMemory}!void {
const extra_index = try self.addExtra(mem_arg);
try self.addInst(.{ .tag = tag, .data = .{ .payload = extra_index } });
}
/// Appends entries to `mir_extra` based on the type of `extra`.
/// Returns the index into `mir_extra`
fn addExtra(self: *Self, extra: anytype) error{OutOfMemory}!u32 {
const fields = std.meta.fields(@TypeOf(extra));
try self.mir_extra.ensureUnusedCapacity(self.gpa, fields.len);
return self.addExtraAssumeCapacity(extra);
}
/// Appends entries to `mir_extra` based on the type of `extra`.
/// Returns the index into `mir_extra`
fn addExtraAssumeCapacity(self: *Self, extra: anytype) error{OutOfMemory}!u32 {
const fields = std.meta.fields(@TypeOf(extra));
const result = @intCast(u32, self.mir_extra.items.len);
inline for (fields) |field| {
self.mir_extra.appendAssumeCapacity(switch (field.field_type) {
u32 => @field(extra, field.name),
else => |field_type| @compileError("Unsupported field type " ++ @typeName(field_type)),
});
}
return result;
}
/// Using a given `Type`, returns the corresponding type
fn typeToValtype(ty: Type, target: std.Target) wasm.Valtype {
return switch (ty.zigTypeTag()) {
.Float => blk: {
const bits = ty.floatBits(target);
if (bits == 16) return wasm.Valtype.i32; // stored/loaded as u16
if (bits == 32) break :blk wasm.Valtype.f32;
if (bits == 64) break :blk wasm.Valtype.f64;
if (bits == 128) break :blk wasm.Valtype.i64;
return wasm.Valtype.i32; // represented as pointer to stack
},
.Int, .Enum => blk: {
const info = ty.intInfo(target);
if (info.bits <= 32) break :blk wasm.Valtype.i32;
if (info.bits > 32 and info.bits <= 128) break :blk wasm.Valtype.i64;
break :blk wasm.Valtype.i32; // represented as pointer to stack
},
else => wasm.Valtype.i32, // all represented as reference/immediate
};
}
/// Using a given `Type`, returns the byte representation of its wasm value type
fn genValtype(ty: Type, target: std.Target) u8 {
return wasm.valtype(typeToValtype(ty, target));
}
/// Using a given `Type`, returns the corresponding wasm value type
/// Differently from `genValtype` this also allows `void` to create a block
/// with no return type
fn genBlockType(ty: Type, target: std.Target) u8 {
return switch (ty.tag()) {
.void, .noreturn => wasm.block_empty,
else => genValtype(ty, target),
};
}
/// Writes the bytecode depending on the given `WValue` in `val`
fn emitWValue(self: *Self, value: WValue) InnerError!void {
switch (value) {
.none, .stack => {}, // no-op
.local => |idx| try self.addLabel(.local_get, idx),
.imm32 => |val| try self.addImm32(@bitCast(i32, val)),
.imm64 => |val| try self.addImm64(val),
.float32 => |val| try self.addInst(.{ .tag = .f32_const, .data = .{ .float32 = val } }),
.float64 => |val| try self.addFloat64(val),
.memory => |ptr| {
const extra_index = try self.addExtra(Mir.Memory{ .pointer = ptr, .offset = 0 });
try self.addInst(.{ .tag = .memory_address, .data = .{ .payload = extra_index } });
},
.memory_offset => |mem_off| {
const extra_index = try self.addExtra(Mir.Memory{ .pointer = mem_off.pointer, .offset = mem_off.offset });
try self.addInst(.{ .tag = .memory_address, .data = .{ .payload = extra_index } });
},
.function_index => |index| try self.addLabel(.function_index, index), // write function index and generate relocation
.stack_offset => try self.addLabel(.local_get, self.bottom_stack_value.local), // caller must ensure to address the offset
}
}
/// Creates one locals for a given `Type`.
/// Returns a corresponding `Wvalue` with `local` as active tag
fn allocLocal(self: *Self, ty: Type) InnerError!WValue {
const valtype = typeToValtype(ty, self.target);
switch (valtype) {
.i32 => if (self.free_locals_i32.popOrNull()) |index| {
return WValue{ .local = index };
},
.i64 => if (self.free_locals_i64.popOrNull()) |index| {
return WValue{ .local = index };
},
.f32 => if (self.free_locals_f32.popOrNull()) |index| {
return WValue{ .local = index };
},
.f64 => if (self.free_locals_f64.popOrNull()) |index| {
return WValue{ .local = index };
},
}
// no local was free to be re-used, so allocate a new local instead
return self.ensureAllocLocal(ty);
}
/// Ensures a new local will be created. This is useful when it's useful
/// to use a zero-initialized local.
fn ensureAllocLocal(self: *Self, ty: Type) InnerError!WValue {
try self.locals.append(self.gpa, genValtype(ty, self.target));
const initial_index = self.local_index;
self.local_index += 1;
return WValue{ .local = initial_index };
}
/// Generates a `wasm.Type` from a given function type.
/// Memory is owned by the caller.
fn genFunctype(gpa: Allocator, cc: std.builtin.CallingConvention, params: []const Type, return_type: Type, target: std.Target) !wasm.Type {
var temp_params = std.ArrayList(wasm.Valtype).init(gpa);
defer temp_params.deinit();
var returns = std.ArrayList(wasm.Valtype).init(gpa);
defer returns.deinit();
if (firstParamSRet(cc, return_type, target)) {
try temp_params.append(.i32); // memory address is always a 32-bit handle
} else if (return_type.hasRuntimeBitsIgnoreComptime()) {
if (cc == .C) {
const res_classes = abi.classifyType(return_type, target);
assert(res_classes[0] == .direct and res_classes[1] == .none);
const scalar_type = abi.scalarType(return_type, target);
try returns.append(typeToValtype(scalar_type, target));
} else {
try returns.append(typeToValtype(return_type, target));
}
} else if (return_type.isError()) {
try returns.append(.i32);
}
// param types
for (params) |param_type| {
if (!param_type.hasRuntimeBitsIgnoreComptime()) continue;
switch (cc) {
.C => {
const param_classes = abi.classifyType(param_type, target);
for (param_classes) |class| {
if (class == .none) continue;
if (class == .direct) {
const scalar_type = abi.scalarType(param_type, target);
try temp_params.append(typeToValtype(scalar_type, target));
} else {
try temp_params.append(typeToValtype(param_type, target));
}
}
},
else => if (isByRef(param_type, target))
try temp_params.append(.i32)
else
try temp_params.append(typeToValtype(param_type, target)),
}
}
return wasm.Type{
.params = temp_params.toOwnedSlice(),
.returns = returns.toOwnedSlice(),
};
}
pub fn generate(
bin_file: *link.File,
src_loc: Module.SrcLoc,
func: *Module.Fn,
air: Air,
liveness: Liveness,
code: *std.ArrayList(u8),
debug_output: codegen.DebugInfoOutput,
) codegen.GenerateSymbolError!codegen.FnResult {
_ = src_loc;
var code_gen: Self = .{
.gpa = bin_file.allocator,
.air = air,
.liveness = liveness,
.values = .{},
.code = code,
.decl_index = func.owner_decl,
.decl = bin_file.options.module.?.declPtr(func.owner_decl),
.err_msg = undefined,
.locals = .{},
.target = bin_file.options.target,
.bin_file = bin_file.cast(link.File.Wasm).?,
.debug_output = debug_output,
.mod_fn = func,
};
defer code_gen.deinit();
genFunc(&code_gen) catch |err| switch (err) {
error.CodegenFail => return codegen.FnResult{ .fail = code_gen.err_msg },
else => |e| return e,
};
return codegen.FnResult{ .appended = {} };
}
fn genFunc(self: *Self) InnerError!void {
const fn_info = self.decl.ty.fnInfo();
var func_type = try genFunctype(self.gpa, fn_info.cc, fn_info.param_types, fn_info.return_type, self.target);
defer func_type.deinit(self.gpa);
self.decl.fn_link.wasm.type_index = try self.bin_file.putOrGetFuncType(func_type);
var cc_result = try self.resolveCallingConventionValues(self.decl.ty);
defer cc_result.deinit(self.gpa);
self.args = cc_result.args;
self.return_value = cc_result.return_value;
try self.addTag(.dbg_prologue_end);
// Generate MIR for function body
try self.genBody(self.air.getMainBody());
// In case we have a return value, but the last instruction is a noreturn (such as a while loop)
// we emit an unreachable instruction to tell the stack validator that part will never be reached.
if (func_type.returns.len != 0 and self.air.instructions.len > 0) {
const inst = @intCast(u32, self.air.instructions.len - 1);
const last_inst_ty = self.air.typeOfIndex(inst);
if (!last_inst_ty.hasRuntimeBitsIgnoreComptime() or last_inst_ty.isNoReturn()) {
try self.addTag(.@"unreachable");
}
}
// End of function body
try self.addTag(.end);
try self.addTag(.dbg_epilogue_begin);
// check if we have to initialize and allocate anything into the stack frame.
// If so, create enough stack space and insert the instructions at the front of the list.
if (self.stack_size > 0) {
var prologue = std.ArrayList(Mir.Inst).init(self.gpa);
defer prologue.deinit();
// load stack pointer
try prologue.append(.{ .tag = .global_get, .data = .{ .label = 0 } });
// store stack pointer so we can restore it when we return from the function
try prologue.append(.{ .tag = .local_tee, .data = .{ .label = self.initial_stack_value.local } });
// get the total stack size
const aligned_stack = std.mem.alignForwardGeneric(u32, self.stack_size, self.stack_alignment);
try prologue.append(.{ .tag = .i32_const, .data = .{ .imm32 = @intCast(i32, aligned_stack) } });
// substract it from the current stack pointer
try prologue.append(.{ .tag = .i32_sub, .data = .{ .tag = {} } });
// Get negative stack aligment
try prologue.append(.{ .tag = .i32_const, .data = .{ .imm32 = @intCast(i32, self.stack_alignment) * -1 } });
// Bitwise-and the value to get the new stack pointer to ensure the pointers are aligned with the abi alignment
try prologue.append(.{ .tag = .i32_and, .data = .{ .tag = {} } });
// store the current stack pointer as the bottom, which will be used to calculate all stack pointer offsets
try prologue.append(.{ .tag = .local_tee, .data = .{ .label = self.bottom_stack_value.local } });
// Store the current stack pointer value into the global stack pointer so other function calls will
// start from this value instead and not overwrite the current stack.
try prologue.append(.{ .tag = .global_set, .data = .{ .label = 0 } });
// reserve space and insert all prologue instructions at the front of the instruction list
// We insert them in reserve order as there is no insertSlice in multiArrayList.
try self.mir_instructions.ensureUnusedCapacity(self.gpa, prologue.items.len);
for (prologue.items) |_, index| {
const inst = prologue.items[prologue.items.len - 1 - index];
self.mir_instructions.insertAssumeCapacity(0, inst);
}
}
var mir: Mir = .{
.instructions = self.mir_instructions.toOwnedSlice(),
.extra = self.mir_extra.toOwnedSlice(self.gpa),
};
defer mir.deinit(self.gpa);
var emit: Emit = .{
.mir = mir,
.bin_file = &self.bin_file.base,
.code = self.code,
.locals = self.locals.items,
.decl = self.decl,
.dbg_output = self.debug_output,
.prev_di_line = 0,
.prev_di_column = 0,
.prev_di_offset = 0,
};
emit.emitMir() catch |err| switch (err) {
error.EmitFail => {
self.err_msg = emit.error_msg.?;
return error.CodegenFail;
},
else => |e| return e,
};
}
const CallWValues = struct {
args: []WValue,
return_value: WValue,
fn deinit(self: *CallWValues, gpa: Allocator) void {
gpa.free(self.args);
self.* = undefined;
}
};
fn resolveCallingConventionValues(self: *Self, fn_ty: Type) InnerError!CallWValues {
const cc = fn_ty.fnCallingConvention();
const param_types = try self.gpa.alloc(Type, fn_ty.fnParamLen());
defer self.gpa.free(param_types);
fn_ty.fnParamTypes(param_types);
var result: CallWValues = .{
.args = &.{},
.return_value = .none,
};
if (cc == .Naked) return result;
var args = std.ArrayList(WValue).init(self.gpa);
defer args.deinit();
// Check if we store the result as a pointer to the stack rather than
// by value
const fn_info = fn_ty.fnInfo();
if (firstParamSRet(fn_info.cc, fn_info.return_type, self.target)) {
// the sret arg will be passed as first argument, therefore we
// set the `return_value` before allocating locals for regular args.
result.return_value = .{ .local = self.local_index };
self.local_index += 1;
}
switch (cc) {
.Unspecified => {
for (param_types) |ty| {
if (!ty.hasRuntimeBitsIgnoreComptime()) {
continue;
}
try args.append(.{ .local = self.local_index });
self.local_index += 1;
}
},
.C => {
for (param_types) |ty| {
const ty_classes = abi.classifyType(ty, self.target);
for (ty_classes) |class| {
if (class == .none) continue;
try args.append(.{ .local = self.local_index });
self.local_index += 1;
}
}
},
else => return self.fail("calling convention '{s}' not supported for Wasm", .{@tagName(cc)}),
}
result.args = args.toOwnedSlice();
return result;
}
fn firstParamSRet(cc: std.builtin.CallingConvention, return_type: Type, target: std.Target) bool {
switch (cc) {
.Unspecified, .Inline => return isByRef(return_type, target),
.C => {
const ty_classes = abi.classifyType(return_type, target);
if (ty_classes[0] == .indirect) return true;
if (ty_classes[0] == .direct and ty_classes[1] == .direct) return true;
return false;
},
else => return false,
}
}
/// For a given `Type`, add debug information to .debug_info at the current position.
/// The actual bytes will be written to the position after relocation.
fn addDbgInfoTypeReloc(self: *Self, ty: Type) !void {
switch (self.debug_output) {
.dwarf => |dwarf| {
assert(ty.hasRuntimeBitsIgnoreComptime());
const dbg_info = &dwarf.dbg_info;
const index = dbg_info.items.len;
try dbg_info.resize(index + 4);
const atom = &self.decl.link.wasm.dbg_info_atom;
try dwarf.addTypeRelocGlobal(atom, ty, @intCast(u32, index));
},
.plan9 => unreachable,
.none => {},
}
}
/// Lowers a Zig type and its value based on a given calling convention to ensure
/// it matches the ABI.
fn lowerArg(self: *Self, cc: std.builtin.CallingConvention, ty: Type, value: WValue) !void {
if (cc != .C) {
return self.lowerToStack(value);
}
const ty_classes = abi.classifyType(ty, self.target);
assert(ty_classes[0] != .none);
switch (ty.zigTypeTag()) {
.Struct, .Union => {
if (ty_classes[0] == .indirect) {
return self.lowerToStack(value);
}
assert(ty_classes[0] == .direct);
const scalar_type = abi.scalarType(ty, self.target);
const abi_size = scalar_type.abiSize(self.target);
const opcode = buildOpcode(.{
.op = .load,
.width = @intCast(u8, abi_size),
.signedness = if (scalar_type.isSignedInt()) .signed else .unsigned,
.valtype1 = typeToValtype(scalar_type, self.target),
});
try self.emitWValue(value);
try self.addMemArg(Mir.Inst.Tag.fromOpcode(opcode), .{
.offset = value.offset(),
.alignment = scalar_type.abiAlignment(self.target),
});
},
.Int, .Float => {
if (ty_classes[1] == .none) {
return self.lowerToStack(value);
}
assert(ty_classes[0] == .direct and ty_classes[1] == .direct);
assert(ty.abiSize(self.target) == 16);
// in this case we have an integer or float that must be lowered as 2 i64's.
try self.emitWValue(value);
try self.addMemArg(.i64_load, .{ .offset = value.offset(), .alignment = 8 });
try self.emitWValue(value);
try self.addMemArg(.i64_load, .{ .offset = value.offset() + 8, .alignment = 8 });
},
else => return self.lowerToStack(value),
}
}
/// Lowers a `WValue` to the stack. This means when the `value` results in
/// `.stack_offset` we calculate the pointer of this offset and use that.
/// The value is left on the stack, and not stored in any temporary.
fn lowerToStack(self: *Self, value: WValue) !void {
switch (value) {
.stack_offset => |offset| {
try self.emitWValue(value);
if (offset > 0) {
switch (self.arch()) {
.wasm32 => {
try self.addImm32(@bitCast(i32, offset));
try self.addTag(.i32_add);
},
.wasm64 => {
try self.addImm64(offset);
try self.addTag(.i64_add);
},
else => unreachable,
}
}
},
else => try self.emitWValue(value),
}
}
/// Creates a local for the initial stack value
/// Asserts `initial_stack_value` is `.none`
fn initializeStack(self: *Self) !void {
assert(self.initial_stack_value == .none);
// Reserve a local to store the current stack pointer
// We can later use this local to set the stack pointer back to the value
// we have stored here.
self.initial_stack_value = try self.ensureAllocLocal(Type.usize);
// Also reserve a local to store the bottom stack value
self.bottom_stack_value = try self.ensureAllocLocal(Type.usize);
}
/// Reads the stack pointer from `Context.initial_stack_value` and writes it
/// to the global stack pointer variable
fn restoreStackPointer(self: *Self) !void {
// only restore the pointer if it was initialized
if (self.initial_stack_value == .none) return;
// Get the original stack pointer's value
try self.emitWValue(self.initial_stack_value);
// save its value in the global stack pointer
try self.addLabel(.global_set, 0);
}
/// From a given type, will create space on the virtual stack to store the value of such type.
/// This returns a `WValue` with its active tag set to `local`, containing the index to the local
/// that points to the position on the virtual stack. This function should be used instead of
/// moveStack unless a local was already created to store the pointer.
///
/// Asserts Type has codegenbits
fn allocStack(self: *Self, ty: Type) !WValue {
assert(ty.hasRuntimeBitsIgnoreComptime());
if (self.initial_stack_value == .none) {
try self.initializeStack();
}
const abi_size = std.math.cast(u32, ty.abiSize(self.target)) orelse {
const module = self.bin_file.base.options.module.?;
return self.fail("Type {} with ABI size of {d} exceeds stack frame size", .{
ty.fmt(module), ty.abiSize(self.target),
});
};
const abi_align = ty.abiAlignment(self.target);
if (abi_align > self.stack_alignment) {
self.stack_alignment = abi_align;
}
const offset = std.mem.alignForwardGeneric(u32, self.stack_size, abi_align);
defer self.stack_size = offset + abi_size;
return WValue{ .stack_offset = offset };
}
/// From a given AIR instruction generates a pointer to the stack where
/// the value of its type will live.
/// This is different from allocStack where this will use the pointer's alignment
/// if it is set, to ensure the stack alignment will be set correctly.
fn allocStackPtr(self: *Self, inst: Air.Inst.Index) !WValue {
const ptr_ty = self.air.typeOfIndex(inst);
const pointee_ty = ptr_ty.childType();
if (self.initial_stack_value == .none) {
try self.initializeStack();
}
if (!pointee_ty.hasRuntimeBitsIgnoreComptime()) {
return self.allocStack(Type.usize); // create a value containing just the stack pointer.
}
const abi_alignment = ptr_ty.ptrAlignment(self.target);
const abi_size = std.math.cast(u32, pointee_ty.abiSize(self.target)) orelse {
const module = self.bin_file.base.options.module.?;
return self.fail("Type {} with ABI size of {d} exceeds stack frame size", .{
pointee_ty.fmt(module), pointee_ty.abiSize(self.target),
});
};
if (abi_alignment > self.stack_alignment) {
self.stack_alignment = abi_alignment;
}
const offset = std.mem.alignForwardGeneric(u32, self.stack_size, abi_alignment);
defer self.stack_size = offset + abi_size;
return WValue{ .stack_offset = offset };
}
/// From given zig bitsize, returns the wasm bitsize
fn toWasmBits(bits: u16) ?u16 {
return for ([_]u16{ 32, 64, 128 }) |wasm_bits| {
if (bits <= wasm_bits) return wasm_bits;
} else null;
}
/// Performs a copy of bytes for a given type. Copying all bytes
/// from rhs to lhs.
fn memcpy(self: *Self, dst: WValue, src: WValue, len: WValue) !void {
// When bulk_memory is enabled, we lower it to wasm's memcpy instruction.
// If not, we lower it ourselves manually
if (std.Target.wasm.featureSetHas(self.target.cpu.features, .bulk_memory)) {
try self.lowerToStack(dst);
try self.lowerToStack(src);
try self.emitWValue(len);
try self.addExtended(.memory_copy);
return;
}
// when the length is comptime-known, rather than a runtime value, we can optimize the generated code by having
// the loop during codegen, rather than inserting a runtime loop into the binary.
switch (len) {
.imm32, .imm64 => {
const length = switch (len) {
.imm32 => |val| val,
.imm64 => |val| val,
else => unreachable,
};
var offset: u32 = 0;
const lhs_base = dst.offset();
const rhs_base = src.offset();
while (offset < length) : (offset += 1) {
// get dst's address to store the result
try self.emitWValue(dst);
// load byte from src's address
try self.emitWValue(src);
switch (self.arch()) {
.wasm32 => {
try self.addMemArg(.i32_load8_u, .{ .offset = rhs_base + offset, .alignment = 1 });
try self.addMemArg(.i32_store8, .{ .offset = lhs_base + offset, .alignment = 1 });
},
.wasm64 => {
try self.addMemArg(.i64_load8_u, .{ .offset = rhs_base + offset, .alignment = 1 });
try self.addMemArg(.i64_store8, .{ .offset = lhs_base + offset, .alignment = 1 });
},
else => unreachable,
}
}
},
else => {
// TODO: We should probably lower this to a call to compiler_rt
// But for now, we implement it manually
var offset = try self.ensureAllocLocal(Type.usize); // local for counter
defer offset.free(self);
// outer block to jump to when loop is done
try self.startBlock(.block, wasm.block_empty);
try self.startBlock(.loop, wasm.block_empty);
// loop condition (offset == length -> break)
{
try self.emitWValue(offset);
try self.emitWValue(len);
switch (self.arch()) {
.wasm32 => try self.addTag(.i32_eq),
.wasm64 => try self.addTag(.i64_eq),
else => unreachable,
}
try self.addLabel(.br_if, 1); // jump out of loop into outer block (finished)
}
// get dst ptr
{
try self.emitWValue(dst);
try self.emitWValue(offset);
switch (self.arch()) {
.wasm32 => try self.addTag(.i32_add),
.wasm64 => try self.addTag(.i64_add),
else => unreachable,
}
}
// get src value and also store in dst
{
try self.emitWValue(src);
try self.emitWValue(offset);
switch (self.arch()) {
.wasm32 => {
try self.addTag(.i32_add);
try self.addMemArg(.i32_load8_u, .{ .offset = src.offset(), .alignment = 1 });
try self.addMemArg(.i32_store8, .{ .offset = dst.offset(), .alignment = 1 });
},
.wasm64 => {
try self.addTag(.i64_add);
try self.addMemArg(.i64_load8_u, .{ .offset = src.offset(), .alignment = 1 });
try self.addMemArg(.i64_store8, .{ .offset = dst.offset(), .alignment = 1 });
},
else => unreachable,
}
}
// increment loop counter
{
try self.emitWValue(offset);
switch (self.arch()) {
.wasm32 => {
try self.addImm32(1);
try self.addTag(.i32_add);
},
.wasm64 => {
try self.addImm64(1);
try self.addTag(.i64_add);
},
else => unreachable,
}
try self.addLabel(.local_set, offset.local);
try self.addLabel(.br, 0); // jump to start of loop
}
try self.endBlock(); // close off loop block
try self.endBlock(); // close off outer block
},
}
}
fn ptrSize(self: *const Self) u16 {
return @divExact(self.target.cpu.arch.ptrBitWidth(), 8);
}
fn arch(self: *const Self) std.Target.Cpu.Arch {
return self.target.cpu.arch;
}
/// For a given `Type`, will return true when the type will be passed
/// by reference, rather than by value
fn isByRef(ty: Type, target: std.Target) bool {
switch (ty.zigTypeTag()) {
.Type,
.ComptimeInt,
.ComptimeFloat,
.EnumLiteral,
.Undefined,
.Null,
.BoundFn,
.Opaque,
=> unreachable,
.NoReturn,
.Void,
.Bool,
.ErrorSet,
.Fn,
.Enum,
.AnyFrame,
=> return false,
.Array,
.Vector,
.Struct,
.Frame,
.Union,
=> return ty.hasRuntimeBitsIgnoreComptime(),
.Int => return ty.intInfo(target).bits > 64,
.Float => return ty.floatBits(target) > 64,
.ErrorUnion => {
const pl_ty = ty.errorUnionPayload();
if (!pl_ty.hasRuntimeBitsIgnoreComptime()) {
return false;
}
return true;
},
.Optional => {
if (ty.optionalReprIsPayload()) return false;
var buf: Type.Payload.ElemType = undefined;
return ty.optionalChild(&buf).hasRuntimeBitsIgnoreComptime();
},
.Pointer => {
// Slices act like struct and will be passed by reference
if (ty.isSlice()) return true;
return false;
},
}
}
/// Creates a new local for a pointer that points to memory with given offset.
/// This can be used to get a pointer to a struct field, error payload, etc.
/// By providing `modify` as action, it will modify the given `ptr_value` instead of making a new
/// local value to store the pointer. This allows for local re-use and improves binary size.
fn buildPointerOffset(self: *Self, ptr_value: WValue, offset: u64, action: enum { modify, new }) InnerError!WValue {
// do not perform arithmetic when offset is 0.
if (offset == 0 and ptr_value.offset() == 0 and action == .modify) return ptr_value;
const result_ptr: WValue = switch (action) {
.new => try self.ensureAllocLocal(Type.usize),
.modify => ptr_value,
};
try self.emitWValue(ptr_value);
if (offset + ptr_value.offset() > 0) {
switch (self.arch()) {
.wasm32 => {
try self.addImm32(@bitCast(i32, @intCast(u32, offset + ptr_value.offset())));
try self.addTag(.i32_add);
},
.wasm64 => {
try self.addImm64(offset + ptr_value.offset());
try self.addTag(.i64_add);
},
else => unreachable,
}
}
try self.addLabel(.local_set, result_ptr.local);
return result_ptr;
}
fn genInst(self: *Self, inst: Air.Inst.Index) !WValue {
const air_tags = self.air.instructions.items(.tag);
return switch (air_tags[inst]) {
.constant => unreachable,
.const_ty => unreachable,
.add => self.airBinOp(inst, .add),
.add_sat => self.airSatBinOp(inst, .add),
.addwrap => self.airWrapBinOp(inst, .add),
.sub => self.airBinOp(inst, .sub),
.sub_sat => self.airSatBinOp(inst, .sub),
.subwrap => self.airWrapBinOp(inst, .sub),
.mul => self.airBinOp(inst, .mul),
.mulwrap => self.airWrapBinOp(inst, .mul),
.div_float,
.div_exact,
.div_trunc,
=> self.airDiv(inst),
.div_floor => self.airDivFloor(inst),
.ceil => self.airCeilFloorTrunc(inst, .ceil),
.floor => self.airCeilFloorTrunc(inst, .floor),
.trunc_float => self.airCeilFloorTrunc(inst, .trunc),
.bit_and => self.airBinOp(inst, .@"and"),
.bit_or => self.airBinOp(inst, .@"or"),
.bool_and => self.airBinOp(inst, .@"and"),
.bool_or => self.airBinOp(inst, .@"or"),
.rem => self.airBinOp(inst, .rem),
.shl => self.airWrapBinOp(inst, .shl),
.shl_exact => self.airBinOp(inst, .shl),
.shl_sat => self.airShlSat(inst),
.shr, .shr_exact => self.airBinOp(inst, .shr),
.xor => self.airBinOp(inst, .xor),
.max => self.airMaxMin(inst, .max),
.min => self.airMaxMin(inst, .min),
.mul_add => self.airMulAdd(inst),
.add_with_overflow => self.airAddSubWithOverflow(inst, .add),
.sub_with_overflow => self.airAddSubWithOverflow(inst, .sub),
.shl_with_overflow => self.airShlWithOverflow(inst),
.mul_with_overflow => self.airMulWithOverflow(inst),
.clz => self.airClz(inst),
.ctz => self.airCtz(inst),
.cmp_eq => self.airCmp(inst, .eq),
.cmp_gte => self.airCmp(inst, .gte),
.cmp_gt => self.airCmp(inst, .gt),
.cmp_lte => self.airCmp(inst, .lte),
.cmp_lt => self.airCmp(inst, .lt),
.cmp_neq => self.airCmp(inst, .neq),
.cmp_vector => self.airCmpVector(inst),
.cmp_lt_errors_len => self.airCmpLtErrorsLen(inst),
.array_elem_val => self.airArrayElemVal(inst),
.array_to_slice => self.airArrayToSlice(inst),
.alloc => self.airAlloc(inst),
.arg => self.airArg(inst),
.bitcast => self.airBitcast(inst),
.block => self.airBlock(inst),
.breakpoint => self.airBreakpoint(inst),
.br => self.airBr(inst),
.bool_to_int => self.airBoolToInt(inst),
.cond_br => self.airCondBr(inst),
.intcast => self.airIntcast(inst),
.fptrunc => self.airFptrunc(inst),
.fpext => self.airFpext(inst),
.float_to_int => self.airFloatToInt(inst),
.int_to_float => self.airIntToFloat(inst),
.get_union_tag => self.airGetUnionTag(inst),
.@"try" => self.airTry(inst),
.try_ptr => self.airTryPtr(inst),
// TODO
.dbg_inline_begin,
.dbg_inline_end,
.dbg_block_begin,
.dbg_block_end,
=> WValue.none,
.dbg_var_ptr => self.airDbgVar(inst, true),
.dbg_var_val => self.airDbgVar(inst, false),
.dbg_stmt => self.airDbgStmt(inst),
.call => self.airCall(inst, .auto),
.call_always_tail => self.airCall(inst, .always_tail),
.call_never_tail => self.airCall(inst, .never_tail),
.call_never_inline => self.airCall(inst, .never_inline),
.is_err => self.airIsErr(inst, .i32_ne),
.is_non_err => self.airIsErr(inst, .i32_eq),
.is_null => self.airIsNull(inst, .i32_eq, .value),
.is_non_null => self.airIsNull(inst, .i32_ne, .value),
.is_null_ptr => self.airIsNull(inst, .i32_eq, .ptr),
.is_non_null_ptr => self.airIsNull(inst, .i32_ne, .ptr),
.load => self.airLoad(inst),
.loop => self.airLoop(inst),
.memset => self.airMemset(inst),
.not => self.airNot(inst),
.optional_payload => self.airOptionalPayload(inst),
.optional_payload_ptr => self.airOptionalPayloadPtr(inst),
.optional_payload_ptr_set => self.airOptionalPayloadPtrSet(inst),
.ptr_add => self.airPtrBinOp(inst, .add),
.ptr_sub => self.airPtrBinOp(inst, .sub),
.ptr_elem_ptr => self.airPtrElemPtr(inst),
.ptr_elem_val => self.airPtrElemVal(inst),
.ptrtoint => self.airPtrToInt(inst),
.ret => self.airRet(inst),
.ret_ptr => self.airRetPtr(inst),
.ret_load => self.airRetLoad(inst),
.splat => self.airSplat(inst),
.select => self.airSelect(inst),
.shuffle => self.airShuffle(inst),
.reduce => self.airReduce(inst),
.aggregate_init => self.airAggregateInit(inst),
.union_init => self.airUnionInit(inst),
.prefetch => self.airPrefetch(inst),
.popcount => self.airPopcount(inst),
.byte_swap => self.airByteSwap(inst),
.slice => self.airSlice(inst),
.slice_len => self.airSliceLen(inst),
.slice_elem_val => self.airSliceElemVal(inst),
.slice_elem_ptr => self.airSliceElemPtr(inst),
.slice_ptr => self.airSlicePtr(inst),
.ptr_slice_len_ptr => self.airPtrSliceFieldPtr(inst, self.ptrSize()),
.ptr_slice_ptr_ptr => self.airPtrSliceFieldPtr(inst, 0),
.store => self.airStore(inst),
.set_union_tag => self.airSetUnionTag(inst),
.struct_field_ptr => self.airStructFieldPtr(inst),
.struct_field_ptr_index_0 => self.airStructFieldPtrIndex(inst, 0),
.struct_field_ptr_index_1 => self.airStructFieldPtrIndex(inst, 1),
.struct_field_ptr_index_2 => self.airStructFieldPtrIndex(inst, 2),
.struct_field_ptr_index_3 => self.airStructFieldPtrIndex(inst, 3),
.struct_field_val => self.airStructFieldVal(inst),
.field_parent_ptr => self.airFieldParentPtr(inst),
.switch_br => self.airSwitchBr(inst),
.trunc => self.airTrunc(inst),
.unreach => self.airUnreachable(inst),
.wrap_optional => self.airWrapOptional(inst),
.unwrap_errunion_payload => self.airUnwrapErrUnionPayload(inst, false),
.unwrap_errunion_payload_ptr => self.airUnwrapErrUnionPayload(inst, true),
.unwrap_errunion_err => self.airUnwrapErrUnionError(inst, false),
.unwrap_errunion_err_ptr => self.airUnwrapErrUnionError(inst, true),
.wrap_errunion_payload => self.airWrapErrUnionPayload(inst),
.wrap_errunion_err => self.airWrapErrUnionErr(inst),
.errunion_payload_ptr_set => self.airErrUnionPayloadPtrSet(inst),
.error_name => self.airErrorName(inst),
.wasm_memory_size => self.airWasmMemorySize(inst),
.wasm_memory_grow => self.airWasmMemoryGrow(inst),
.memcpy => self.airMemcpy(inst),
.mul_sat,
.mod,
.assembly,
.ret_addr,
.frame_addr,
.bit_reverse,
.is_err_ptr,
.is_non_err_ptr,
.sqrt,
.sin,
.cos,
.tan,
.exp,
.exp2,
.log,
.log2,
.log10,
.fabs,
.round,
.neg,
.cmpxchg_weak,
.cmpxchg_strong,
.fence,
.atomic_load,
.atomic_store_unordered,
.atomic_store_monotonic,
.atomic_store_release,
.atomic_store_seq_cst,
.atomic_rmw,
.tag_name,
.err_return_trace,
.set_err_return_trace,
.is_named_enum_value,
.error_set_has_value,
=> |tag| return self.fail("TODO: Implement wasm inst: {s}", .{@tagName(tag)}),
.add_optimized,
.addwrap_optimized,
.sub_optimized,
.subwrap_optimized,
.mul_optimized,
.mulwrap_optimized,
.div_float_optimized,
.div_trunc_optimized,
.div_floor_optimized,
.div_exact_optimized,
.rem_optimized,
.mod_optimized,
.neg_optimized,
.cmp_lt_optimized,
.cmp_lte_optimized,
.cmp_eq_optimized,
.cmp_gte_optimized,
.cmp_gt_optimized,
.cmp_neq_optimized,
.cmp_vector_optimized,
.reduce_optimized,
.float_to_int_optimized,
=> return self.fail("TODO implement optimized float mode", .{}),
};
}
fn genBody(self: *Self, body: []const Air.Inst.Index) InnerError!void {
for (body) |inst| {
const result = try self.genInst(inst);
if (result != .none) {
assert(result != .stack); // not allowed to store stack values as we cannot keep track of where they are on the stack
try self.values.putNoClobber(self.gpa, Air.indexToRef(inst), result);
}
}
}
fn airRet(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
const un_op = self.air.instructions.items(.data)[inst].un_op;
const operand = try self.resolveInst(un_op);
const fn_info = self.decl.ty.fnInfo();
const ret_ty = fn_info.return_type;
// result must be stored in the stack and we return a pointer
// to the stack instead
if (self.return_value != .none) {
try self.store(self.return_value, operand, ret_ty, 0);
} else if (fn_info.cc == .C and ret_ty.hasRuntimeBitsIgnoreComptime()) {
switch (ret_ty.zigTypeTag()) {
// Aggregate types can be lowered as a singular value
.Struct, .Union => {
const scalar_type = abi.scalarType(ret_ty, self.target);
try self.emitWValue(operand);
const opcode = buildOpcode(.{
.op = .load,
.width = @intCast(u8, scalar_type.abiSize(self.target) * 8),
.signedness = if (scalar_type.isSignedInt()) .signed else .unsigned,
.valtype1 = typeToValtype(scalar_type, self.target),
});
try self.addMemArg(Mir.Inst.Tag.fromOpcode(opcode), .{
.offset = operand.offset(),
.alignment = scalar_type.abiAlignment(self.target),
});
},
else => try self.emitWValue(operand),
}
} else {
if (!ret_ty.hasRuntimeBitsIgnoreComptime() and ret_ty.isError()) {
try self.addImm32(0);
} else {
try self.emitWValue(operand);
}
}
try self.restoreStackPointer();
try self.addTag(.@"return");
return WValue{ .none = {} };
}
fn airRetPtr(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
const child_type = self.air.typeOfIndex(inst).childType();
if (!child_type.isFnOrHasRuntimeBitsIgnoreComptime()) {
return self.allocStack(Type.usize); // create pointer to void
}
const fn_info = self.decl.ty.fnInfo();
if (firstParamSRet(fn_info.cc, fn_info.return_type, self.target)) {
return self.return_value;
}
return self.allocStackPtr(inst);
}
fn airRetLoad(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
const un_op = self.air.instructions.items(.data)[inst].un_op;
const operand = try self.resolveInst(un_op);
const ret_ty = self.air.typeOf(un_op).childType();
if (!ret_ty.hasRuntimeBitsIgnoreComptime()) {
if (ret_ty.isError()) {
try self.addImm32(0);
} else {
return WValue.none;
}
}
const fn_info = self.decl.ty.fnInfo();
if (!firstParamSRet(fn_info.cc, fn_info.return_type, self.target)) {
// leave on the stack
_ = try self.load(operand, ret_ty, 0);
}
try self.restoreStackPointer();
try self.addTag(.@"return");
return .none;
}
fn airCall(self: *Self, inst: Air.Inst.Index, modifier: std.builtin.CallOptions.Modifier) InnerError!WValue {
if (modifier == .always_tail) return self.fail("TODO implement tail calls for wasm", .{});
const pl_op = self.air.instructions.items(.data)[inst].pl_op;
const extra = self.air.extraData(Air.Call, pl_op.payload);
const args = self.air.extra[extra.end..][0..extra.data.args_len];
const ty = self.air.typeOf(pl_op.operand);
const fn_ty = switch (ty.zigTypeTag()) {
.Fn => ty,
.Pointer => ty.childType(),
else => unreachable,
};
const ret_ty = fn_ty.fnReturnType();
const fn_info = fn_ty.fnInfo();
const first_param_sret = firstParamSRet(fn_info.cc, fn_info.return_type, self.target);
const callee: ?*Decl = blk: {
const func_val = self.air.value(pl_op.operand) orelse break :blk null;
const module = self.bin_file.base.options.module.?;
if (func_val.castTag(.function)) |func| {
break :blk module.declPtr(func.data.owner_decl);
} else if (func_val.castTag(.extern_fn)) |extern_fn| {
const ext_decl = module.declPtr(extern_fn.data.owner_decl);
const ext_info = ext_decl.ty.fnInfo();
var func_type = try genFunctype(self.gpa, ext_info.cc, ext_info.param_types, ext_info.return_type, self.target);
defer func_type.deinit(self.gpa);
ext_decl.fn_link.wasm.type_index = try self.bin_file.putOrGetFuncType(func_type);
try self.bin_file.addOrUpdateImport(
mem.sliceTo(ext_decl.name, 0),
ext_decl.link.wasm.sym_index,
ext_decl.getExternFn().?.lib_name,
ext_decl.fn_link.wasm.type_index,
);
break :blk ext_decl;
} else if (func_val.castTag(.decl_ref)) |decl_ref| {
break :blk module.declPtr(decl_ref.data);
}
return self.fail("Expected a function, but instead found type '{}'", .{func_val.tag()});
};
const sret = if (first_param_sret) blk: {
const sret_local = try self.allocStack(ret_ty);
try self.lowerToStack(sret_local);
break :blk sret_local;
} else WValue{ .none = {} };
for (args) |arg| {
const arg_ref = @intToEnum(Air.Inst.Ref, arg);
const arg_val = try self.resolveInst(arg_ref);
const arg_ty = self.air.typeOf(arg_ref);
if (!arg_ty.hasRuntimeBitsIgnoreComptime()) continue;
try self.lowerArg(fn_ty.fnInfo().cc, arg_ty, arg_val);
}
if (callee) |direct| {
try self.addLabel(.call, direct.link.wasm.sym_index);
} else {
// in this case we call a function pointer
// so load its value onto the stack
std.debug.assert(ty.zigTypeTag() == .Pointer);
const operand = try self.resolveInst(pl_op.operand);
try self.emitWValue(operand);
var fn_type = try genFunctype(self.gpa, fn_info.cc, fn_info.param_types, fn_info.return_type, self.target);
defer fn_type.deinit(self.gpa);
const fn_type_index = try self.bin_file.putOrGetFuncType(fn_type);
try self.addLabel(.call_indirect, fn_type_index);
}
if (self.liveness.isUnused(inst) or (!ret_ty.hasRuntimeBitsIgnoreComptime() and !ret_ty.isError())) {
return WValue.none;
} else if (ret_ty.isNoReturn()) {
try self.addTag(.@"unreachable");
return WValue.none;
} else if (first_param_sret) {
return sret;
// TODO: Make this less fragile and optimize
} else if (fn_ty.fnInfo().cc == .C and ret_ty.zigTypeTag() == .Struct or ret_ty.zigTypeTag() == .Union) {
const result_local = try self.allocLocal(ret_ty);
try self.addLabel(.local_set, result_local.local);
const scalar_type = abi.scalarType(ret_ty, self.target);
const result = try self.allocStack(scalar_type);
try self.store(result, result_local, scalar_type, 0);
return result;
} else {
const result_local = try self.allocLocal(ret_ty);
try self.addLabel(.local_set, result_local.local);
return result_local;
}
}
fn airAlloc(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
return self.allocStackPtr(inst);
}
fn airStore(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
const bin_op = self.air.instructions.items(.data)[inst].bin_op;
const lhs = try self.resolveInst(bin_op.lhs);
const rhs = try self.resolveInst(bin_op.rhs);
const ty = self.air.typeOf(bin_op.lhs).childType();
try self.store(lhs, rhs, ty, 0);
return WValue{ .none = {} };
}
fn store(self: *Self, lhs: WValue, rhs: WValue, ty: Type, offset: u32) InnerError!void {
assert(!(lhs != .stack and rhs == .stack));
switch (ty.zigTypeTag()) {
.ErrorUnion => {
const pl_ty = ty.errorUnionPayload();
if (!pl_ty.hasRuntimeBitsIgnoreComptime()) {
return self.store(lhs, rhs, Type.anyerror, 0);
}
const len = @intCast(u32, ty.abiSize(self.target));
return self.memcpy(lhs, rhs, .{ .imm32 = len });
},
.Optional => {
if (ty.isPtrLikeOptional()) {
return self.store(lhs, rhs, Type.usize, 0);
}
var buf: Type.Payload.ElemType = undefined;
const pl_ty = ty.optionalChild(&buf);
if (!pl_ty.hasRuntimeBitsIgnoreComptime()) {
return self.store(lhs, rhs, Type.u8, 0);
}
if (pl_ty.zigTypeTag() == .ErrorSet) {
return self.store(lhs, rhs, Type.anyerror, 0);
}
const len = @intCast(u32, ty.abiSize(self.target));
return self.memcpy(lhs, rhs, .{ .imm32 = len });
},
.Struct, .Array, .Union, .Vector => {
const len = @intCast(u32, ty.abiSize(self.target));
return self.memcpy(lhs, rhs, .{ .imm32 = len });
},
.Pointer => {
if (ty.isSlice()) {
// store pointer first
// lower it to the stack so we do not have to store rhs into a local first
try self.emitWValue(lhs);
const ptr_local = try self.load(rhs, Type.usize, 0);
try self.store(.{ .stack = {} }, ptr_local, Type.usize, 0 + lhs.offset());
// retrieve length from rhs, and store that alongside lhs as well
try self.emitWValue(lhs);
const len_local = try self.load(rhs, Type.usize, self.ptrSize());
try self.store(.{ .stack = {} }, len_local, Type.usize, self.ptrSize() + lhs.offset());
return;
}
},
.Int => if (ty.intInfo(self.target).bits > 64) {
try self.emitWValue(lhs);
const lsb = try self.load(rhs, Type.u64, 0);
try self.store(.{ .stack = {} }, lsb, Type.u64, 0 + lhs.offset());
try self.emitWValue(lhs);
const msb = try self.load(rhs, Type.u64, 8);
try self.store(.{ .stack = {} }, msb, Type.u64, 8 + lhs.offset());
return;
},
else => {},
}
try self.emitWValue(lhs);
// In this case we're actually interested in storing the stack position
// into lhs, so we calculate that and emit that instead
try self.lowerToStack(rhs);
const valtype = typeToValtype(ty, self.target);
const abi_size = @intCast(u8, ty.abiSize(self.target));
const opcode = buildOpcode(.{
.valtype1 = valtype,
.width = abi_size * 8,
.op = .store,
});
// store rhs value at stack pointer's location in memory
try self.addMemArg(
Mir.Inst.Tag.fromOpcode(opcode),
.{ .offset = offset + lhs.offset(), .alignment = ty.abiAlignment(self.target) },
);
}
fn airLoad(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
const ty_op = self.air.instructions.items(.data)[inst].ty_op;
const operand = try self.resolveInst(ty_op.operand);
const ty = self.air.getRefType(ty_op.ty);
if (!ty.hasRuntimeBitsIgnoreComptime()) return WValue{ .none = {} };
if (isByRef(ty, self.target)) {
const new_local = try self.allocStack(ty);
try self.store(new_local, operand, ty, 0);
return new_local;
}
const stack_loaded = try self.load(operand, ty, 0);
return stack_loaded.toLocal(self, ty);
}
/// Loads an operand from the linear memory section.
/// NOTE: Leaves the value on the stack.
fn load(self: *Self, operand: WValue, ty: Type, offset: u32) InnerError!WValue {
// load local's value from memory by its stack position
try self.emitWValue(operand);
const abi_size = @intCast(u8, ty.abiSize(self.target));
const opcode = buildOpcode(.{
.valtype1 = typeToValtype(ty, self.target),
.width = abi_size * 8,
.op = .load,
.signedness = .unsigned,
});
try self.addMemArg(
Mir.Inst.Tag.fromOpcode(opcode),
.{ .offset = offset + operand.offset(), .alignment = ty.abiAlignment(self.target) },
);
return WValue{ .stack = {} };
}
fn airArg(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
const arg_index = self.arg_index;
const arg = self.args[arg_index];
const cc = self.decl.ty.fnInfo().cc;
const arg_ty = self.air.typeOfIndex(inst);
if (cc == .C) {
const arg_classes = abi.classifyType(arg_ty, self.target);
for (arg_classes) |class| {
if (class != .none) {
self.arg_index += 1;
}
}
// When we have an argument that's passed using more than a single parameter,
// we combine them into a single stack value
if (arg_classes[0] == .direct and arg_classes[1] == .direct) {
if (arg_ty.zigTypeTag() != .Int) {
return self.fail(
"TODO: Implement C-ABI argument for type '{}'",
.{arg_ty.fmt(self.bin_file.base.options.module.?)},
);
}
const result = try self.allocStack(arg_ty);
try self.store(result, arg, Type.u64, 0);
try self.store(result, self.args[arg_index + 1], Type.u64, 8);
return result;
}
} else {
self.arg_index += 1;
}
switch (self.debug_output) {
.dwarf => |dwarf| {
// TODO: Get the original arg index rather than wasm arg index
const name = self.mod_fn.getParamName(self.bin_file.base.options.module.?, arg_index);
const leb_size = link.File.Wasm.getULEB128Size(arg.local);
const dbg_info = &dwarf.dbg_info;
try dbg_info.ensureUnusedCapacity(3 + leb_size + 5 + name.len + 1);
// wasm locations are encoded as follow:
// DW_OP_WASM_location wasm-op
// where wasm-op is defined as
// wasm-op := wasm-local | wasm-global | wasm-operand_stack
// where each argument is encoded as
// <opcode> i:uleb128
dbg_info.appendSliceAssumeCapacity(&.{
@enumToInt(link.File.Dwarf.AbbrevKind.parameter),
std.dwarf.OP.WASM_location,
std.dwarf.OP.WASM_local,
});
leb.writeULEB128(dbg_info.writer(), arg.local) catch unreachable;
try self.addDbgInfoTypeReloc(arg_ty);
dbg_info.appendSliceAssumeCapacity(name);
dbg_info.appendAssumeCapacity(0);
},
else => {},
}
return arg;
}
fn airBinOp(self: *Self, inst: Air.Inst.Index, op: Op) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const bin_op = self.air.instructions.items(.data)[inst].bin_op;
const lhs = try self.resolveInst(bin_op.lhs);
const rhs = try self.resolveInst(bin_op.rhs);
const ty = self.air.typeOf(bin_op.lhs);
const stack_value = try self.binOp(lhs, rhs, ty, op);
return stack_value.toLocal(self, ty);
}
/// Performs a binary operation on the given `WValue`'s
/// NOTE: THis leaves the value on top of the stack.
fn binOp(self: *Self, lhs: WValue, rhs: WValue, ty: Type, op: Op) InnerError!WValue {
assert(!(lhs != .stack and rhs == .stack));
if (isByRef(ty, self.target)) {
if (ty.zigTypeTag() == .Int) {
return self.binOpBigInt(lhs, rhs, ty, op);
} else {
return self.fail(
"TODO: Implement binary operation for type: {}",
.{ty.fmt(self.bin_file.base.options.module.?)},
);
}
}
if (ty.isAnyFloat() and ty.floatBits(self.target) == 16) {
return self.binOpFloat16(lhs, rhs, op);
}
const opcode: wasm.Opcode = buildOpcode(.{
.op = op,
.valtype1 = typeToValtype(ty, self.target),
.signedness = if (ty.isSignedInt()) .signed else .unsigned,
});
try self.emitWValue(lhs);
try self.emitWValue(rhs);
try self.addTag(Mir.Inst.Tag.fromOpcode(opcode));
return WValue{ .stack = {} };
}
/// Performs a binary operation for 16-bit floats.
/// NOTE: Leaves the result value on the stack
fn binOpFloat16(self: *Self, lhs: WValue, rhs: WValue, op: Op) InnerError!WValue {
const opcode: wasm.Opcode = buildOpcode(.{ .op = op, .valtype1 = .f32, .signedness = .unsigned });
_ = try self.fpext(lhs, Type.f16, Type.f32);
_ = try self.fpext(rhs, Type.f16, Type.f32);
try self.addTag(Mir.Inst.Tag.fromOpcode(opcode));
return self.fptrunc(.{ .stack = {} }, Type.f32, Type.f16);
}
fn binOpBigInt(self: *Self, lhs: WValue, rhs: WValue, ty: Type, op: Op) InnerError!WValue {
if (ty.intInfo(self.target).bits > 128) {
return self.fail("TODO: Implement binary operation for big integer", .{});
}
if (op != .add and op != .sub) {
return self.fail("TODO: Implement binary operation for big integers", .{});
}
const result = try self.allocStack(ty);
var lhs_high_bit = try (try self.load(lhs, Type.u64, 0)).toLocal(self, Type.u64);
defer lhs_high_bit.free(self);
var rhs_high_bit = try (try self.load(rhs, Type.u64, 0)).toLocal(self, Type.u64);
defer rhs_high_bit.free(self);
var high_op_res = try (try self.binOp(lhs_high_bit, rhs_high_bit, Type.u64, op)).toLocal(self, Type.u64);
defer high_op_res.free(self);
const lhs_low_bit = try self.load(lhs, Type.u64, 8);
const rhs_low_bit = try self.load(rhs, Type.u64, 8);
const low_op_res = try self.binOp(lhs_low_bit, rhs_low_bit, Type.u64, op);
const lt = if (op == .add) blk: {
break :blk try self.cmp(high_op_res, rhs_high_bit, Type.u64, .lt);
} else if (op == .sub) blk: {
break :blk try self.cmp(lhs_high_bit, rhs_high_bit, Type.u64, .lt);
} else unreachable;
const tmp = try self.intcast(lt, Type.u32, Type.u64);
var tmp_op = try (try self.binOp(low_op_res, tmp, Type.u64, op)).toLocal(self, Type.u64);
defer tmp_op.free(self);
try self.store(result, high_op_res, Type.u64, 0);
try self.store(result, tmp_op, Type.u64, 8);
return result;
}
fn airWrapBinOp(self: *Self, inst: Air.Inst.Index, op: Op) InnerError!WValue {
const bin_op = self.air.instructions.items(.data)[inst].bin_op;
const lhs = try self.resolveInst(bin_op.lhs);
const rhs = try self.resolveInst(bin_op.rhs);
const ty = self.air.typeOf(bin_op.lhs);
if (ty.zigTypeTag() == .Vector) {
return self.fail("TODO: Implement wrapping arithmetic for vectors", .{});
}
return (try self.wrapBinOp(lhs, rhs, ty, op)).toLocal(self, ty);
}
/// Performs a wrapping binary operation.
/// Asserts rhs is not a stack value when lhs also isn't.
/// NOTE: Leaves the result on the stack when its Type is <= 64 bits
fn wrapBinOp(self: *Self, lhs: WValue, rhs: WValue, ty: Type, op: Op) InnerError!WValue {
const bin_local = try self.binOp(lhs, rhs, ty, op);
return self.wrapOperand(bin_local, ty);
}
/// Wraps an operand based on a given type's bitsize.
/// Asserts `Type` is <= 128 bits.
/// NOTE: When the Type is <= 64 bits, leaves the value on top of the stack.
fn wrapOperand(self: *Self, operand: WValue, ty: Type) InnerError!WValue {
assert(ty.abiSize(self.target) <= 16);
const bitsize = ty.intInfo(self.target).bits;
const wasm_bits = toWasmBits(bitsize) orelse {
return self.fail("TODO: Implement wrapOperand for bitsize '{d}'", .{bitsize});
};
if (wasm_bits == bitsize) return operand;
if (wasm_bits == 128) {
assert(operand != .stack);
const lsb = try self.load(operand, Type.u64, 8);
const result_ptr = try self.allocStack(ty);
try self.emitWValue(result_ptr);
try self.store(.{ .stack = {} }, lsb, Type.u64, 8 + result_ptr.offset());
const result = (@as(u64, 1) << @intCast(u6, 64 - (wasm_bits - bitsize))) - 1;
try self.emitWValue(result_ptr);
_ = try self.load(operand, Type.u64, 0);
try self.addImm64(result);
try self.addTag(.i64_and);
try self.addMemArg(.i64_store, .{ .offset = result_ptr.offset(), .alignment = 8 });
return result_ptr;
}
const result = (@as(u64, 1) << @intCast(u6, bitsize)) - 1;
try self.emitWValue(operand);
if (bitsize <= 32) {
try self.addImm32(@bitCast(i32, @intCast(u32, result)));
try self.addTag(.i32_and);
} else if (bitsize <= 64) {
try self.addImm64(result);
try self.addTag(.i64_and);
} else unreachable;
return WValue{ .stack = {} };
}
fn lowerParentPtr(self: *Self, ptr_val: Value, ptr_child_ty: Type) InnerError!WValue {
switch (ptr_val.tag()) {
.decl_ref_mut => {
const decl_index = ptr_val.castTag(.decl_ref_mut).?.data.decl_index;
return self.lowerParentPtrDecl(ptr_val, decl_index);
},
.decl_ref => {
const decl_index = ptr_val.castTag(.decl_ref).?.data;
return self.lowerParentPtrDecl(ptr_val, decl_index);
},
.variable => {
const decl_index = ptr_val.castTag(.variable).?.data.owner_decl;
return self.lowerParentPtrDecl(ptr_val, decl_index);
},
.field_ptr => {
const field_ptr = ptr_val.castTag(.field_ptr).?.data;
const parent_ty = field_ptr.container_ty;
const parent_ptr = try self.lowerParentPtr(field_ptr.container_ptr, parent_ty);
const offset = switch (parent_ty.zigTypeTag()) {
.Struct => blk: {
const offset = parent_ty.structFieldOffset(field_ptr.field_index, self.target);
break :blk offset;
},
.Union => blk: {
const layout: Module.Union.Layout = parent_ty.unionGetLayout(self.target);
if (layout.payload_size == 0) break :blk 0;
if (layout.payload_align > layout.tag_align) break :blk 0;
// tag is stored first so calculate offset from where payload starts
const offset = @intCast(u32, std.mem.alignForwardGeneric(u64, layout.tag_size, layout.tag_align));
break :blk offset;
},
else => unreachable,
};
return switch (parent_ptr) {
.memory => |ptr| WValue{
.memory_offset = .{
.pointer = ptr,
.offset = @intCast(u32, offset),
},
},
.memory_offset => |mem_off| WValue{
.memory_offset = .{
.pointer = mem_off.pointer,
.offset = @intCast(u32, offset) + mem_off.offset,
},
},
else => unreachable,
};
},
.elem_ptr => {
const elem_ptr = ptr_val.castTag(.elem_ptr).?.data;
const index = elem_ptr.index;
const offset = index * ptr_child_ty.abiSize(self.target);
const array_ptr = try self.lowerParentPtr(elem_ptr.array_ptr, elem_ptr.elem_ty);
return WValue{ .memory_offset = .{
.pointer = array_ptr.memory,
.offset = @intCast(u32, offset),
} };
},
.opt_payload_ptr => {
const payload_ptr = ptr_val.castTag(.opt_payload_ptr).?.data;
const parent_ptr = try self.lowerParentPtr(payload_ptr.container_ptr, payload_ptr.container_ty);
var buf: Type.Payload.ElemType = undefined;
const payload_ty = payload_ptr.container_ty.optionalChild(&buf);
if (!payload_ty.hasRuntimeBitsIgnoreComptime() or payload_ty.optionalReprIsPayload()) {
return parent_ptr;
}
const abi_size = payload_ptr.container_ty.abiSize(self.target);
const offset = abi_size - payload_ty.abiSize(self.target);
return WValue{ .memory_offset = .{
.pointer = parent_ptr.memory,
.offset = @intCast(u32, offset),
} };
},
else => |tag| return self.fail("TODO: Implement lowerParentPtr for tag: {}", .{tag}),
}
}
fn lowerParentPtrDecl(self: *Self, ptr_val: Value, decl_index: Module.Decl.Index) InnerError!WValue {
const module = self.bin_file.base.options.module.?;
const decl = module.declPtr(decl_index);
module.markDeclAlive(decl);
var ptr_ty_payload: Type.Payload.ElemType = .{
.base = .{ .tag = .single_mut_pointer },
.data = decl.ty,
};
const ptr_ty = Type.initPayload(&ptr_ty_payload.base);
return self.lowerDeclRefValue(.{ .ty = ptr_ty, .val = ptr_val }, decl_index);
}
fn lowerDeclRefValue(self: *Self, tv: TypedValue, decl_index: Module.Decl.Index) InnerError!WValue {
if (tv.ty.isSlice()) {
return WValue{ .memory = try self.bin_file.lowerUnnamedConst(tv, decl_index) };
}
const module = self.bin_file.base.options.module.?;
const decl = module.declPtr(decl_index);
if (decl.ty.zigTypeTag() != .Fn and !decl.ty.hasRuntimeBitsIgnoreComptime()) {
return WValue{ .imm32 = 0xaaaaaaaa };
}
module.markDeclAlive(decl);
const target_sym_index = decl.link.wasm.sym_index;
if (decl.ty.zigTypeTag() == .Fn) {
try self.bin_file.addTableFunction(target_sym_index);
return WValue{ .function_index = target_sym_index };
} else return WValue{ .memory = target_sym_index };
}
/// Converts a signed integer to its 2's complement form and returns
/// an unsigned integer instead.
/// Asserts bitsize <= 64
fn toTwosComplement(value: anytype, bits: u7) std.meta.Int(.unsigned, @typeInfo(@TypeOf(value)).Int.bits) {
const T = @TypeOf(value);
comptime assert(@typeInfo(T) == .Int);
comptime assert(@typeInfo(T).Int.signedness == .signed);
assert(bits <= 64);
const WantedT = std.meta.Int(.unsigned, @typeInfo(T).Int.bits);
if (value >= 0) return @bitCast(WantedT, value);
const max_value = @intCast(u64, (@as(u65, 1) << bits) - 1);
const flipped = @intCast(T, (~-@as(i65, value)) + 1);
const result = @bitCast(WantedT, flipped) & max_value;
return @intCast(WantedT, result);
}
fn lowerConstant(self: *Self, val: Value, ty: Type) InnerError!WValue {
if (val.isUndefDeep()) return self.emitUndefined(ty);
if (val.castTag(.decl_ref)) |decl_ref| {
const decl_index = decl_ref.data;
return self.lowerDeclRefValue(.{ .ty = ty, .val = val }, decl_index);
}
if (val.castTag(.decl_ref_mut)) |decl_ref_mut| {
const decl_index = decl_ref_mut.data.decl_index;
return self.lowerDeclRefValue(.{ .ty = ty, .val = val }, decl_index);
}
const target = self.target;
switch (ty.zigTypeTag()) {
.Void => return WValue{ .none = {} },
.Int => {
const int_info = ty.intInfo(self.target);
switch (int_info.signedness) {
.signed => switch (int_info.bits) {
0...32 => return WValue{ .imm32 = @intCast(u32, toTwosComplement(
val.toSignedInt(),
@intCast(u6, int_info.bits),
)) },
33...64 => return WValue{ .imm64 = toTwosComplement(
val.toSignedInt(),
@intCast(u7, int_info.bits),
) },
else => unreachable,
},
.unsigned => switch (int_info.bits) {
0...32 => return WValue{ .imm32 = @intCast(u32, val.toUnsignedInt(target)) },
33...64 => return WValue{ .imm64 = val.toUnsignedInt(target) },
else => unreachable,
},
}
},
.Bool => return WValue{ .imm32 = @intCast(u32, val.toUnsignedInt(target)) },
.Float => switch (ty.floatBits(self.target)) {
16 => return WValue{ .imm32 = @bitCast(u16, val.toFloat(f16)) },
32 => return WValue{ .float32 = val.toFloat(f32) },
64 => return WValue{ .float64 = val.toFloat(f64) },
else => unreachable,
},
.Pointer => switch (val.tag()) {
.field_ptr, .elem_ptr, .opt_payload_ptr => {
return self.lowerParentPtr(val, ty.childType());
},
.int_u64, .one => return WValue{ .imm32 = @intCast(u32, val.toUnsignedInt(target)) },
.zero, .null_value => return WValue{ .imm32 = 0 },
else => return self.fail("Wasm TODO: lowerConstant for other const pointer tag {}", .{val.tag()}),
},
.Enum => {
if (val.castTag(.enum_field_index)) |field_index| {
switch (ty.tag()) {
.enum_simple => return WValue{ .imm32 = field_index.data },
.enum_full, .enum_nonexhaustive => {
const enum_full = ty.cast(Type.Payload.EnumFull).?.data;
if (enum_full.values.count() != 0) {
const tag_val = enum_full.values.keys()[field_index.data];
return self.lowerConstant(tag_val, enum_full.tag_ty);
} else {
return WValue{ .imm32 = field_index.data };
}
},
.enum_numbered => {
const index = field_index.data;
const enum_data = ty.castTag(.enum_numbered).?.data;
const enum_val = enum_data.values.keys()[index];
return self.lowerConstant(enum_val, enum_data.tag_ty);
},
else => return self.fail("TODO: lowerConstant for enum tag: {}", .{ty.tag()}),
}
} else {
var int_tag_buffer: Type.Payload.Bits = undefined;
const int_tag_ty = ty.intTagType(&int_tag_buffer);
return self.lowerConstant(val, int_tag_ty);
}
},
.ErrorSet => switch (val.tag()) {
.@"error" => {
const kv = try self.bin_file.base.options.module.?.getErrorValue(val.getError().?);
return WValue{ .imm32 = kv.value };
},
else => return WValue{ .imm32 = 0 },
},
.ErrorUnion => {
const error_type = ty.errorUnionSet();
const is_pl = val.errorUnionIsPayload();
const err_val = if (!is_pl) val else Value.initTag(.zero);
return self.lowerConstant(err_val, error_type);
},
.Optional => if (ty.optionalReprIsPayload()) {
var buf: Type.Payload.ElemType = undefined;
const pl_ty = ty.optionalChild(&buf);
if (val.castTag(.opt_payload)) |payload| {
return self.lowerConstant(payload.data, pl_ty);
} else if (val.isNull()) {
return WValue{ .imm32 = 0 };
} else {
return self.lowerConstant(val, pl_ty);
}
} else {
const is_pl = val.tag() == .opt_payload;
return WValue{ .imm32 = if (is_pl) @as(u32, 1) else 0 };
},
else => |zig_type| return self.fail("Wasm TODO: LowerConstant for zigTypeTag {}", .{zig_type}),
}
}
fn emitUndefined(self: *Self, ty: Type) InnerError!WValue {
switch (ty.zigTypeTag()) {
.Bool, .ErrorSet => return WValue{ .imm32 = 0xaaaaaaaa },
.Int => switch (ty.intInfo(self.target).bits) {
0...32 => return WValue{ .imm32 = 0xaaaaaaaa },
33...64 => return WValue{ .imm64 = 0xaaaaaaaaaaaaaaaa },
else => unreachable,
},
.Float => switch (ty.floatBits(self.target)) {
16 => return WValue{ .imm32 = 0xaaaaaaaa },
32 => return WValue{ .float32 = @bitCast(f32, @as(u32, 0xaaaaaaaa)) },
64 => return WValue{ .float64 = @bitCast(f64, @as(u64, 0xaaaaaaaaaaaaaaaa)) },
else => unreachable,
},
.Pointer => switch (self.arch()) {
.wasm32 => return WValue{ .imm32 = 0xaaaaaaaa },
.wasm64 => return WValue{ .imm64 = 0xaaaaaaaaaaaaaaaa },
else => unreachable,
},
.Optional => {
var buf: Type.Payload.ElemType = undefined;
const pl_ty = ty.optionalChild(&buf);
if (ty.optionalReprIsPayload()) {
return self.emitUndefined(pl_ty);
}
return WValue{ .imm32 = 0xaaaaaaaa };
},
.ErrorUnion => {
return WValue{ .imm32 = 0xaaaaaaaa };
},
else => return self.fail("Wasm TODO: emitUndefined for type: {}\n", .{ty.zigTypeTag()}),
}
}
/// Returns a `Value` as a signed 32 bit value.
/// It's illegal to provide a value with a type that cannot be represented
/// as an integer value.
fn valueAsI32(self: Self, val: Value, ty: Type) i32 {
const target = self.target;
switch (ty.zigTypeTag()) {
.Enum => {
if (val.castTag(.enum_field_index)) |field_index| {
switch (ty.tag()) {
.enum_simple => return @bitCast(i32, field_index.data),
.enum_full, .enum_nonexhaustive => {
const enum_full = ty.cast(Type.Payload.EnumFull).?.data;
if (enum_full.values.count() != 0) {
const tag_val = enum_full.values.keys()[field_index.data];
return self.valueAsI32(tag_val, enum_full.tag_ty);
} else return @bitCast(i32, field_index.data);
},
.enum_numbered => {
const index = field_index.data;
const enum_data = ty.castTag(.enum_numbered).?.data;
return self.valueAsI32(enum_data.values.keys()[index], enum_data.tag_ty);
},
else => unreachable,
}
} else {
var int_tag_buffer: Type.Payload.Bits = undefined;
const int_tag_ty = ty.intTagType(&int_tag_buffer);
return self.valueAsI32(val, int_tag_ty);
}
},
.Int => switch (ty.intInfo(self.target).signedness) {
.signed => return @truncate(i32, val.toSignedInt()),
.unsigned => return @bitCast(i32, @truncate(u32, val.toUnsignedInt(target))),
},
.ErrorSet => {
const kv = self.bin_file.base.options.module.?.getErrorValue(val.getError().?) catch unreachable; // passed invalid `Value` to function
return @bitCast(i32, kv.value);
},
.Bool => return @intCast(i32, val.toSignedInt()),
.Pointer => return @intCast(i32, val.toSignedInt()),
else => unreachable, // Programmer called this function for an illegal type
}
}
fn airBlock(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
const ty_pl = self.air.instructions.items(.data)[inst].ty_pl;
const block_ty = self.air.getRefType(ty_pl.ty);
const wasm_block_ty = genBlockType(block_ty, self.target);
const extra = self.air.extraData(Air.Block, ty_pl.payload);
const body = self.air.extra[extra.end..][0..extra.data.body_len];
// if wasm_block_ty is non-empty, we create a register to store the temporary value
const block_result: WValue = if (wasm_block_ty != wasm.block_empty) blk: {
const ty: Type = if (isByRef(block_ty, self.target)) Type.u32 else block_ty;
break :blk try self.allocLocal(ty);
} else WValue.none;
try self.startBlock(.block, wasm.block_empty);
// Here we set the current block idx, so breaks know the depth to jump
// to when breaking out.
try self.blocks.putNoClobber(self.gpa, inst, .{
.label = self.block_depth,
.value = block_result,
});
try self.genBody(body);
try self.endBlock();
return block_result;
}
/// appends a new wasm block to the code section and increases the `block_depth` by 1
fn startBlock(self: *Self, block_tag: wasm.Opcode, valtype: u8) !void {
self.block_depth += 1;
try self.addInst(.{
.tag = Mir.Inst.Tag.fromOpcode(block_tag),
.data = .{ .block_type = valtype },
});
}
/// Ends the current wasm block and decreases the `block_depth` by 1
fn endBlock(self: *Self) !void {
try self.addTag(.end);
self.block_depth -= 1;
}
fn airLoop(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
const ty_pl = self.air.instructions.items(.data)[inst].ty_pl;
const loop = self.air.extraData(Air.Block, ty_pl.payload);
const body = self.air.extra[loop.end..][0..loop.data.body_len];
// result type of loop is always 'noreturn', meaning we can always
// emit the wasm type 'block_empty'.
try self.startBlock(.loop, wasm.block_empty);
try self.genBody(body);
// breaking to the index of a loop block will continue the loop instead
try self.addLabel(.br, 0);
try self.endBlock();
return .none;
}
fn airCondBr(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
const pl_op = self.air.instructions.items(.data)[inst].pl_op;
const condition = try self.resolveInst(pl_op.operand);
const extra = self.air.extraData(Air.CondBr, pl_op.payload);
const then_body = self.air.extra[extra.end..][0..extra.data.then_body_len];
const else_body = self.air.extra[extra.end + then_body.len ..][0..extra.data.else_body_len];
// TODO: Handle death instructions for then and else body
// result type is always noreturn, so use `block_empty` as type.
try self.startBlock(.block, wasm.block_empty);
// emit the conditional value
try self.emitWValue(condition);
// we inserted the block in front of the condition
// so now check if condition matches. If not, break outside this block
// and continue with the then codepath
try self.addLabel(.br_if, 0);
try self.genBody(else_body);
try self.endBlock();
// Outer block that matches the condition
try self.genBody(then_body);
return .none;
}
fn airCmp(self: *Self, inst: Air.Inst.Index, op: std.math.CompareOperator) InnerError!WValue {
const bin_op = self.air.instructions.items(.data)[inst].bin_op;
const lhs = try self.resolveInst(bin_op.lhs);
const rhs = try self.resolveInst(bin_op.rhs);
const operand_ty = self.air.typeOf(bin_op.lhs);
return (try self.cmp(lhs, rhs, operand_ty, op)).toLocal(self, Type.u32); // comparison result is always 32 bits
}
/// Compares two operands.
/// Asserts rhs is not a stack value when the lhs isn't a stack value either
/// NOTE: This leaves the result on top of the stack, rather than a new local.
fn cmp(self: *Self, lhs: WValue, rhs: WValue, ty: Type, op: std.math.CompareOperator) InnerError!WValue {
assert(!(lhs != .stack and rhs == .stack));
if (ty.zigTypeTag() == .Optional and !ty.optionalReprIsPayload()) {
var buf: Type.Payload.ElemType = undefined;
const payload_ty = ty.optionalChild(&buf);
if (payload_ty.hasRuntimeBitsIgnoreComptime()) {
// When we hit this case, we must check the value of optionals
// that are not pointers. This means first checking against non-null for
// both lhs and rhs, as well as checking the payload are matching of lhs and rhs
return self.cmpOptionals(lhs, rhs, ty, op);
}
} else if (isByRef(ty, self.target)) {
return self.cmpBigInt(lhs, rhs, ty, op);
} else if (ty.isAnyFloat() and ty.floatBits(self.target) == 16) {
return self.cmpFloat16(lhs, rhs, op);
}
// ensure that when we compare pointers, we emit
// the true pointer of a stack value, rather than the stack pointer.
try self.lowerToStack(lhs);
try self.lowerToStack(rhs);
const signedness: std.builtin.Signedness = blk: {
// by default we tell the operand type is unsigned (i.e. bools and enum values)
if (ty.zigTypeTag() != .Int) break :blk .unsigned;
// incase of an actual integer, we emit the correct signedness
break :blk ty.intInfo(self.target).signedness;
};
const opcode: wasm.Opcode = buildOpcode(.{
.valtype1 = typeToValtype(ty, self.target),
.op = switch (op) {
.lt => .lt,
.lte => .le,
.eq => .eq,
.neq => .ne,
.gte => .ge,
.gt => .gt,
},
.signedness = signedness,
});
try self.addTag(Mir.Inst.Tag.fromOpcode(opcode));
return WValue{ .stack = {} };
}
/// Compares 16-bit floats
/// NOTE: The result value remains on top of the stack.
fn cmpFloat16(self: *Self, lhs: WValue, rhs: WValue, op: std.math.CompareOperator) InnerError!WValue {
const opcode: wasm.Opcode = buildOpcode(.{
.op = switch (op) {
.lt => .lt,
.lte => .le,
.eq => .eq,
.neq => .ne,
.gte => .ge,
.gt => .gt,
},
.valtype1 = .f32,
.signedness = .unsigned,
});
_ = try self.fpext(lhs, Type.f16, Type.f32);
_ = try self.fpext(rhs, Type.f16, Type.f32);
try self.addTag(Mir.Inst.Tag.fromOpcode(opcode));
return WValue{ .stack = {} };
}
fn airCmpVector(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
_ = inst;
return self.fail("TODO implement airCmpVector for wasm", .{});
}
fn airCmpLtErrorsLen(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const un_op = self.air.instructions.items(.data)[inst].un_op;
const operand = try self.resolveInst(un_op);
_ = operand;
return self.fail("TODO implement airCmpLtErrorsLen for wasm", .{});
}
fn airBr(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
const br = self.air.instructions.items(.data)[inst].br;
const block = self.blocks.get(br.block_inst).?;
// if operand has codegen bits we should break with a value
if (self.air.typeOf(br.operand).hasRuntimeBitsIgnoreComptime()) {
const operand = try self.resolveInst(br.operand);
try self.lowerToStack(operand);
if (block.value != .none) {
try self.addLabel(.local_set, block.value.local);
}
}
// We map every block to its block index.
// We then determine how far we have to jump to it by subtracting it from current block depth
const idx: u32 = self.block_depth - block.label;
try self.addLabel(.br, idx);
return .none;
}
fn airNot(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
const ty_op = self.air.instructions.items(.data)[inst].ty_op;
const operand = try self.resolveInst(ty_op.operand);
const operand_ty = self.air.typeOf(ty_op.operand);
if (operand_ty.zigTypeTag() == .Bool) {
try self.emitWValue(operand);
try self.addTag(.i32_eqz);
const not_tmp = try self.allocLocal(operand_ty);
try self.addLabel(.local_set, not_tmp.local);
return not_tmp;
} else {
const operand_bits = operand_ty.intInfo(self.target).bits;
const wasm_bits = toWasmBits(operand_bits) orelse {
return self.fail("TODO: Implement binary NOT for integer with bitsize '{d}'", .{operand_bits});
};
switch (wasm_bits) {
32 => {
const bin_op = try self.binOp(operand, .{ .imm32 = ~@as(u32, 0) }, operand_ty, .xor);
return (try self.wrapOperand(bin_op, operand_ty)).toLocal(self, operand_ty);
},
64 => {
const bin_op = try self.binOp(operand, .{ .imm64 = ~@as(u64, 0) }, operand_ty, .xor);
return (try self.wrapOperand(bin_op, operand_ty)).toLocal(self, operand_ty);
},
128 => {
const result_ptr = try self.allocStack(operand_ty);
try self.emitWValue(result_ptr);
const msb = try self.load(operand, Type.u64, 0);
const msb_xor = try self.binOp(msb, .{ .imm64 = ~@as(u64, 0) }, Type.u64, .xor);
try self.store(.{ .stack = {} }, msb_xor, Type.u64, 0 + result_ptr.offset());
try self.emitWValue(result_ptr);
const lsb = try self.load(operand, Type.u64, 8);
const lsb_xor = try self.binOp(lsb, .{ .imm64 = ~@as(u64, 0) }, Type.u64, .xor);
try self.store(result_ptr, lsb_xor, Type.u64, 8 + result_ptr.offset());
return result_ptr;
},
else => unreachable,
}
}
}
fn airBreakpoint(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
_ = self;
_ = inst;
// unsupported by wasm itself. Can be implemented once we support DWARF
// for wasm
return .none;
}
fn airUnreachable(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
_ = inst;
try self.addTag(.@"unreachable");
return .none;
}
fn airBitcast(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
const ty_op = self.air.instructions.items(.data)[inst].ty_op;
return self.resolveInst(ty_op.operand);
}
fn airStructFieldPtr(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
const ty_pl = self.air.instructions.items(.data)[inst].ty_pl;
const extra = self.air.extraData(Air.StructField, ty_pl.payload);
const struct_ptr = try self.resolveInst(extra.data.struct_operand);
const struct_ty = self.air.typeOf(extra.data.struct_operand).childType();
const offset = std.math.cast(u32, struct_ty.structFieldOffset(extra.data.field_index, self.target)) orelse {
const module = self.bin_file.base.options.module.?;
return self.fail("Field type '{}' too big to fit into stack frame", .{
struct_ty.structFieldType(extra.data.field_index).fmt(module),
});
};
return self.structFieldPtr(struct_ptr, offset);
}
fn airStructFieldPtrIndex(self: *Self, inst: Air.Inst.Index, index: u32) InnerError!WValue {
const ty_op = self.air.instructions.items(.data)[inst].ty_op;
const struct_ptr = try self.resolveInst(ty_op.operand);
const struct_ty = self.air.typeOf(ty_op.operand).childType();
const field_ty = struct_ty.structFieldType(index);
const offset = std.math.cast(u32, struct_ty.structFieldOffset(index, self.target)) orelse {
const module = self.bin_file.base.options.module.?;
return self.fail("Field type '{}' too big to fit into stack frame", .{
field_ty.fmt(module),
});
};
return self.structFieldPtr(struct_ptr, offset);
}
fn structFieldPtr(self: *Self, struct_ptr: WValue, offset: u32) InnerError!WValue {
switch (struct_ptr) {
.stack_offset => |stack_offset| {
return WValue{ .stack_offset = stack_offset + offset };
},
else => return self.buildPointerOffset(struct_ptr, offset, .new),
}
}
fn airStructFieldVal(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const ty_pl = self.air.instructions.items(.data)[inst].ty_pl;
const struct_field = self.air.extraData(Air.StructField, ty_pl.payload).data;
const struct_ty = self.air.typeOf(struct_field.struct_operand);
const operand = try self.resolveInst(struct_field.struct_operand);
const field_index = struct_field.field_index;
const field_ty = struct_ty.structFieldType(field_index);
if (!field_ty.hasRuntimeBitsIgnoreComptime()) return WValue{ .none = {} };
const offset = std.math.cast(u32, struct_ty.structFieldOffset(field_index, self.target)) orelse {
const module = self.bin_file.base.options.module.?;
return self.fail("Field type '{}' too big to fit into stack frame", .{field_ty.fmt(module)});
};
if (isByRef(field_ty, self.target)) {
switch (operand) {
.stack_offset => |stack_offset| {
return WValue{ .stack_offset = stack_offset + offset };
},
else => return self.buildPointerOffset(operand, offset, .new),
}
}
const field = try self.load(operand, field_ty, offset);
return field.toLocal(self, field_ty);
}
fn airSwitchBr(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
// result type is always 'noreturn'
const blocktype = wasm.block_empty;
const pl_op = self.air.instructions.items(.data)[inst].pl_op;
const target = try self.resolveInst(pl_op.operand);
const target_ty = self.air.typeOf(pl_op.operand);
const switch_br = self.air.extraData(Air.SwitchBr, pl_op.payload);
var extra_index: usize = switch_br.end;
var case_i: u32 = 0;
// a list that maps each value with its value and body based on the order inside the list.
const CaseValue = struct { integer: i32, value: Value };
var case_list = try std.ArrayList(struct {
values: []const CaseValue,
body: []const Air.Inst.Index,
}).initCapacity(self.gpa, switch_br.data.cases_len);
defer for (case_list.items) |case| {
self.gpa.free(case.values);
} else case_list.deinit();
var lowest_maybe: ?i32 = null;
var highest_maybe: ?i32 = null;
while (case_i < switch_br.data.cases_len) : (case_i += 1) {
const case = self.air.extraData(Air.SwitchBr.Case, extra_index);
const items = @ptrCast([]const Air.Inst.Ref, self.air.extra[case.end..][0..case.data.items_len]);
const case_body = self.air.extra[case.end + items.len ..][0..case.data.body_len];
extra_index = case.end + items.len + case_body.len;
const values = try self.gpa.alloc(CaseValue, items.len);
errdefer self.gpa.free(values);
for (items) |ref, i| {
const item_val = self.air.value(ref).?;
const int_val = self.valueAsI32(item_val, target_ty);
if (lowest_maybe == null or int_val < lowest_maybe.?) {
lowest_maybe = int_val;
}
if (highest_maybe == null or int_val > highest_maybe.?) {
highest_maybe = int_val;
}
values[i] = .{ .integer = int_val, .value = item_val };
}
case_list.appendAssumeCapacity(.{ .values = values, .body = case_body });
try self.startBlock(.block, blocktype);
}
// When highest and lowest are null, we have no cases and can use a jump table
const lowest = lowest_maybe orelse 0;
const highest = highest_maybe orelse 0;
// When the highest and lowest values are seperated by '50',
// we define it as sparse and use an if/else-chain, rather than a jump table.
// When the target is an integer size larger than u32, we have no way to use the value
// as an index, therefore we also use an if/else-chain for those cases.
// TODO: Benchmark this to find a proper value, LLVM seems to draw the line at '40~45'.
const is_sparse = highest - lowest > 50 or target_ty.bitSize(self.target) > 32;
const else_body = self.air.extra[extra_index..][0..switch_br.data.else_body_len];
const has_else_body = else_body.len != 0;
if (has_else_body) {
try self.startBlock(.block, blocktype);
}
if (!is_sparse) {
// Generate the jump table 'br_table' when the prongs are not sparse.
// The value 'target' represents the index into the table.
// Each index in the table represents a label to the branch
// to jump to.
try self.startBlock(.block, blocktype);
try self.emitWValue(target);
if (lowest < 0) {
// since br_table works using indexes, starting from '0', we must ensure all values
// we put inside, are atleast 0.
try self.addImm32(lowest * -1);
try self.addTag(.i32_add);
} else if (lowest > 0) {
// make the index start from 0 by substracting the lowest value
try self.addImm32(lowest);
try self.addTag(.i32_sub);
}
// Account for default branch so always add '1'
const depth = @intCast(u32, highest - lowest + @boolToInt(has_else_body)) + 1;
const jump_table: Mir.JumpTable = .{ .length = depth };
const table_extra_index = try self.addExtra(jump_table);
try self.addInst(.{ .tag = .br_table, .data = .{ .payload = table_extra_index } });
try self.mir_extra.ensureUnusedCapacity(self.gpa, depth);
var value = lowest;
while (value <= highest) : (value += 1) {
// idx represents the branch we jump to
const idx = blk: {
for (case_list.items) |case, idx| {
for (case.values) |case_value| {
if (case_value.integer == value) break :blk @intCast(u32, idx);
}
}
// error sets are almost always sparse so we use the default case
// for errors that are not present in any branch. This is fine as this default
// case will never be hit for those cases but we do save runtime cost and size
// by using a jump table for this instead of if-else chains.
break :blk if (has_else_body or target_ty.zigTypeTag() == .ErrorSet) case_i else unreachable;
};
self.mir_extra.appendAssumeCapacity(idx);
} else if (has_else_body) {
self.mir_extra.appendAssumeCapacity(case_i); // default branch
}
try self.endBlock();
}
const signedness: std.builtin.Signedness = blk: {
// by default we tell the operand type is unsigned (i.e. bools and enum values)
if (target_ty.zigTypeTag() != .Int) break :blk .unsigned;
// incase of an actual integer, we emit the correct signedness
break :blk target_ty.intInfo(self.target).signedness;
};
for (case_list.items) |case| {
// when sparse, we use if/else-chain, so emit conditional checks
if (is_sparse) {
// for single value prong we can emit a simple if
if (case.values.len == 1) {
try self.emitWValue(target);
const val = try self.lowerConstant(case.values[0].value, target_ty);
try self.emitWValue(val);
const opcode = buildOpcode(.{
.valtype1 = typeToValtype(target_ty, self.target),
.op = .ne, // not equal, because we want to jump out of this block if it does not match the condition.
.signedness = signedness,
});
try self.addTag(Mir.Inst.Tag.fromOpcode(opcode));
try self.addLabel(.br_if, 0);
} else {
// in multi-value prongs we must check if any prongs match the target value.
try self.startBlock(.block, blocktype);
for (case.values) |value| {
try self.emitWValue(target);
const val = try self.lowerConstant(value.value, target_ty);
try self.emitWValue(val);
const opcode = buildOpcode(.{
.valtype1 = typeToValtype(target_ty, self.target),
.op = .eq,
.signedness = signedness,
});
try self.addTag(Mir.Inst.Tag.fromOpcode(opcode));
try self.addLabel(.br_if, 0);
}
// value did not match any of the prong values
try self.addLabel(.br, 1);
try self.endBlock();
}
}
try self.genBody(case.body);
try self.endBlock();
}
if (has_else_body) {
try self.genBody(else_body);
try self.endBlock();
}
return .none;
}
fn airIsErr(self: *Self, inst: Air.Inst.Index, opcode: wasm.Opcode) InnerError!WValue {
const un_op = self.air.instructions.items(.data)[inst].un_op;
const operand = try self.resolveInst(un_op);
const err_union_ty = self.air.typeOf(un_op);
const pl_ty = err_union_ty.errorUnionPayload();
if (err_union_ty.errorUnionSet().errorSetIsEmpty()) {
switch (opcode) {
.i32_ne => return WValue{ .imm32 = 0 },
.i32_eq => return WValue{ .imm32 = 1 },
else => unreachable,
}
}
try self.emitWValue(operand);
if (pl_ty.hasRuntimeBitsIgnoreComptime()) {
try self.addMemArg(.i32_load16_u, .{
.offset = operand.offset() + @intCast(u32, errUnionErrorOffset(pl_ty, self.target)),
.alignment = Type.anyerror.abiAlignment(self.target),
});
}
// Compare the error value with '0'
try self.addImm32(0);
try self.addTag(Mir.Inst.Tag.fromOpcode(opcode));
const is_err_tmp = try self.allocLocal(Type.i32);
try self.addLabel(.local_set, is_err_tmp.local);
return is_err_tmp;
}
fn airUnwrapErrUnionPayload(self: *Self, inst: Air.Inst.Index, op_is_ptr: bool) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const ty_op = self.air.instructions.items(.data)[inst].ty_op;
const operand = try self.resolveInst(ty_op.operand);
const op_ty = self.air.typeOf(ty_op.operand);
const err_ty = if (op_is_ptr) op_ty.childType() else op_ty;
const payload_ty = err_ty.errorUnionPayload();
if (!payload_ty.hasRuntimeBitsIgnoreComptime()) return WValue{ .none = {} };
const pl_offset = @intCast(u32, errUnionPayloadOffset(payload_ty, self.target));
if (op_is_ptr or isByRef(payload_ty, self.target)) {
return self.buildPointerOffset(operand, pl_offset, .new);
}
const payload = try self.load(operand, payload_ty, pl_offset);
return payload.toLocal(self, payload_ty);
}
fn airUnwrapErrUnionError(self: *Self, inst: Air.Inst.Index, op_is_ptr: bool) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const ty_op = self.air.instructions.items(.data)[inst].ty_op;
const operand = try self.resolveInst(ty_op.operand);
const op_ty = self.air.typeOf(ty_op.operand);
const err_ty = if (op_is_ptr) op_ty.childType() else op_ty;
const payload_ty = err_ty.errorUnionPayload();
if (err_ty.errorUnionSet().errorSetIsEmpty()) {
return WValue{ .imm32 = 0 };
}
if (op_is_ptr or !payload_ty.hasRuntimeBitsIgnoreComptime()) {
return operand;
}
const error_val = try self.load(operand, Type.anyerror, @intCast(u32, errUnionErrorOffset(payload_ty, self.target)));
return error_val.toLocal(self, Type.anyerror);
}
fn airWrapErrUnionPayload(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const ty_op = self.air.instructions.items(.data)[inst].ty_op;
const operand = try self.resolveInst(ty_op.operand);
const err_ty = self.air.typeOfIndex(inst);
const pl_ty = self.air.typeOf(ty_op.operand);
if (!pl_ty.hasRuntimeBitsIgnoreComptime()) {
return operand;
}
const err_union = try self.allocStack(err_ty);
const payload_ptr = try self.buildPointerOffset(err_union, @intCast(u32, errUnionPayloadOffset(pl_ty, self.target)), .new);
try self.store(payload_ptr, operand, pl_ty, 0);
// ensure we also write '0' to the error part, so any present stack value gets overwritten by it.
try self.emitWValue(err_union);
try self.addImm32(0);
const err_val_offset = @intCast(u32, errUnionErrorOffset(pl_ty, self.target));
try self.addMemArg(.i32_store16, .{ .offset = err_union.offset() + err_val_offset, .alignment = 2 });
return err_union;
}
fn airWrapErrUnionErr(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const ty_op = self.air.instructions.items(.data)[inst].ty_op;
const operand = try self.resolveInst(ty_op.operand);
const err_ty = self.air.getRefType(ty_op.ty);
const pl_ty = err_ty.errorUnionPayload();
if (!pl_ty.hasRuntimeBitsIgnoreComptime()) {
return operand;
}
const err_union = try self.allocStack(err_ty);
// store error value
try self.store(err_union, operand, Type.anyerror, @intCast(u32, errUnionErrorOffset(pl_ty, self.target)));
// write 'undefined' to the payload
const payload_ptr = try self.buildPointerOffset(err_union, @intCast(u32, errUnionPayloadOffset(pl_ty, self.target)), .new);
const len = @intCast(u32, err_ty.errorUnionPayload().abiSize(self.target));
try self.memset(payload_ptr, .{ .imm32 = len }, .{ .imm32 = 0xaaaaaaaa });
return err_union;
}
fn airIntcast(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const ty_op = self.air.instructions.items(.data)[inst].ty_op;
const ty = self.air.getRefType(ty_op.ty);
const operand = try self.resolveInst(ty_op.operand);
const operand_ty = self.air.typeOf(ty_op.operand);
if (ty.zigTypeTag() == .Vector or operand_ty.zigTypeTag() == .Vector) {
return self.fail("todo Wasm intcast for vectors", .{});
}
if (ty.abiSize(self.target) > 16 or operand_ty.abiSize(self.target) > 16) {
return self.fail("todo Wasm intcast for bitsize > 128", .{});
}
return (try self.intcast(operand, operand_ty, ty)).toLocal(self, ty);
}
/// Upcasts or downcasts an integer based on the given and wanted types,
/// and stores the result in a new operand.
/// Asserts type's bitsize <= 128
/// NOTE: May leave the result on the top of the stack.
fn intcast(self: *Self, operand: WValue, given: Type, wanted: Type) InnerError!WValue {
const given_info = given.intInfo(self.target);
const wanted_info = wanted.intInfo(self.target);
assert(given_info.bits <= 128);
assert(wanted_info.bits <= 128);
const op_bits = toWasmBits(given_info.bits).?;
const wanted_bits = toWasmBits(wanted_info.bits).?;
if (op_bits == wanted_bits) return operand;
if (op_bits > 32 and op_bits <= 64 and wanted_bits == 32) {
try self.emitWValue(operand);
try self.addTag(.i32_wrap_i64);
} else if (op_bits == 32 and wanted_bits > 32 and wanted_bits <= 64) {
try self.emitWValue(operand);
try self.addTag(switch (wanted_info.signedness) {
.signed => .i64_extend_i32_s,
.unsigned => .i64_extend_i32_u,
});
} else if (wanted_bits == 128) {
// for 128bit integers we store the integer in the virtual stack, rather than a local
const stack_ptr = try self.allocStack(wanted);
try self.emitWValue(stack_ptr);
// for 32 bit integers, we first coerce the value into a 64 bit integer before storing it
// meaning less store operations are required.
const lhs = if (op_bits == 32) blk: {
break :blk try self.intcast(operand, given, if (wanted.isSignedInt()) Type.i64 else Type.u64);
} else operand;
// store msb first
try self.store(.{ .stack = {} }, lhs, Type.u64, 0 + stack_ptr.offset());
// For signed integers we shift msb by 63 (64bit integer - 1 sign bit) and store remaining value
if (wanted.isSignedInt()) {
try self.emitWValue(stack_ptr);
const shr = try self.binOp(lhs, .{ .imm64 = 63 }, Type.i64, .shr);
try self.store(.{ .stack = {} }, shr, Type.u64, 8 + stack_ptr.offset());
} else {
// Ensure memory of lsb is zero'd
try self.store(stack_ptr, .{ .imm64 = 0 }, Type.u64, 8);
}
return stack_ptr;
} else return self.load(operand, wanted, 0);
return WValue{ .stack = {} };
}
fn airIsNull(self: *Self, inst: Air.Inst.Index, opcode: wasm.Opcode, op_kind: enum { value, ptr }) InnerError!WValue {
const un_op = self.air.instructions.items(.data)[inst].un_op;
const operand = try self.resolveInst(un_op);
const op_ty = self.air.typeOf(un_op);
const optional_ty = if (op_kind == .ptr) op_ty.childType() else op_ty;
const is_null = try self.isNull(operand, optional_ty, opcode);
return is_null.toLocal(self, optional_ty);
}
/// For a given type and operand, checks if it's considered `null`.
/// NOTE: Leaves the result on the stack
fn isNull(self: *Self, operand: WValue, optional_ty: Type, opcode: wasm.Opcode) InnerError!WValue {
try self.emitWValue(operand);
if (!optional_ty.optionalReprIsPayload()) {
var buf: Type.Payload.ElemType = undefined;
const payload_ty = optional_ty.optionalChild(&buf);
// When payload is zero-bits, we can treat operand as a value, rather than
// a pointer to the stack value
if (payload_ty.hasRuntimeBitsIgnoreComptime()) {
try self.addMemArg(.i32_load8_u, .{ .offset = operand.offset(), .alignment = 1 });
}
}
// Compare the null value with '0'
try self.addImm32(0);
try self.addTag(Mir.Inst.Tag.fromOpcode(opcode));
return WValue{ .stack = {} };
}
fn airOptionalPayload(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const ty_op = self.air.instructions.items(.data)[inst].ty_op;
const operand = try self.resolveInst(ty_op.operand);
const opt_ty = self.air.typeOf(ty_op.operand);
const payload_ty = self.air.typeOfIndex(inst);
if (!payload_ty.hasRuntimeBitsIgnoreComptime()) return WValue{ .none = {} };
if (opt_ty.optionalReprIsPayload()) return operand;
const offset = opt_ty.abiSize(self.target) - payload_ty.abiSize(self.target);
if (isByRef(payload_ty, self.target)) {
return self.buildPointerOffset(operand, offset, .new);
}
const payload = try self.load(operand, payload_ty, @intCast(u32, offset));
return payload.toLocal(self, payload_ty);
}
fn airOptionalPayloadPtr(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const ty_op = self.air.instructions.items(.data)[inst].ty_op;
const operand = try self.resolveInst(ty_op.operand);
const opt_ty = self.air.typeOf(ty_op.operand).childType();
var buf: Type.Payload.ElemType = undefined;
const payload_ty = opt_ty.optionalChild(&buf);
if (!payload_ty.hasRuntimeBitsIgnoreComptime() or opt_ty.optionalReprIsPayload()) {
return operand;
}
const offset = opt_ty.abiSize(self.target) - payload_ty.abiSize(self.target);
return self.buildPointerOffset(operand, offset, .new);
}
fn airOptionalPayloadPtrSet(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
const ty_op = self.air.instructions.items(.data)[inst].ty_op;
const operand = try self.resolveInst(ty_op.operand);
const opt_ty = self.air.typeOf(ty_op.operand).childType();
var buf: Type.Payload.ElemType = undefined;
const payload_ty = opt_ty.optionalChild(&buf);
if (!payload_ty.hasRuntimeBitsIgnoreComptime()) {
return self.fail("TODO: Implement OptionalPayloadPtrSet for optional with zero-sized type {}", .{payload_ty.fmtDebug()});
}
if (opt_ty.optionalReprIsPayload()) {
return operand;
}
const offset = std.math.cast(u32, opt_ty.abiSize(self.target) - payload_ty.abiSize(self.target)) orelse {
const module = self.bin_file.base.options.module.?;
return self.fail("Optional type {} too big to fit into stack frame", .{opt_ty.fmt(module)});
};
try self.emitWValue(operand);
try self.addImm32(1);
try self.addMemArg(.i32_store8, .{ .offset = operand.offset(), .alignment = 1 });
return self.buildPointerOffset(operand, offset, .new);
}
fn airWrapOptional(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const ty_op = self.air.instructions.items(.data)[inst].ty_op;
const payload_ty = self.air.typeOf(ty_op.operand);
if (!payload_ty.hasRuntimeBitsIgnoreComptime()) {
const non_null_bit = try self.allocStack(Type.initTag(.u1));
try self.emitWValue(non_null_bit);
try self.addImm32(1);
try self.addMemArg(.i32_store8, .{ .offset = non_null_bit.offset(), .alignment = 1 });
return non_null_bit;
}
const operand = try self.resolveInst(ty_op.operand);
const op_ty = self.air.typeOfIndex(inst);
if (op_ty.optionalReprIsPayload()) {
return operand;
}
const offset = std.math.cast(u32, op_ty.abiSize(self.target) - payload_ty.abiSize(self.target)) orelse {
const module = self.bin_file.base.options.module.?;
return self.fail("Optional type {} too big to fit into stack frame", .{op_ty.fmt(module)});
};
// Create optional type, set the non-null bit, and store the operand inside the optional type
const result = try self.allocStack(op_ty);
try self.emitWValue(result);
try self.addImm32(1);
try self.addMemArg(.i32_store8, .{ .offset = result.offset(), .alignment = 1 });
const payload_ptr = try self.buildPointerOffset(result, offset, .new);
try self.store(payload_ptr, operand, payload_ty, 0);
return result;
}
fn airSlice(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const ty_pl = self.air.instructions.items(.data)[inst].ty_pl;
const bin_op = self.air.extraData(Air.Bin, ty_pl.payload).data;
const lhs = try self.resolveInst(bin_op.lhs);
const rhs = try self.resolveInst(bin_op.rhs);
const slice_ty = self.air.typeOfIndex(inst);
const slice = try self.allocStack(slice_ty);
try self.store(slice, lhs, Type.usize, 0);
try self.store(slice, rhs, Type.usize, self.ptrSize());
return slice;
}
fn airSliceLen(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const ty_op = self.air.instructions.items(.data)[inst].ty_op;
const operand = try self.resolveInst(ty_op.operand);
const len = try self.load(operand, Type.usize, self.ptrSize());
return len.toLocal(self, Type.usize);
}
fn airSliceElemVal(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const bin_op = self.air.instructions.items(.data)[inst].bin_op;
const slice_ty = self.air.typeOf(bin_op.lhs);
const slice = try self.resolveInst(bin_op.lhs);
const index = try self.resolveInst(bin_op.rhs);
const elem_ty = slice_ty.childType();
const elem_size = elem_ty.abiSize(self.target);
// load pointer onto stack
_ = try self.load(slice, Type.usize, 0);
// calculate index into slice
try self.emitWValue(index);
try self.addImm32(@bitCast(i32, @intCast(u32, elem_size)));
try self.addTag(.i32_mul);
try self.addTag(.i32_add);
const result = try self.allocLocal(elem_ty);
try self.addLabel(.local_set, result.local);
if (isByRef(elem_ty, self.target)) {
return result;
}
const elem_val = try self.load(result, elem_ty, 0);
return elem_val.toLocal(self, elem_ty);
}
fn airSliceElemPtr(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue.none;
const ty_pl = self.air.instructions.items(.data)[inst].ty_pl;
const bin_op = self.air.extraData(Air.Bin, ty_pl.payload).data;
const elem_ty = self.air.getRefType(ty_pl.ty).childType();
const elem_size = elem_ty.abiSize(self.target);
const slice = try self.resolveInst(bin_op.lhs);
const index = try self.resolveInst(bin_op.rhs);
_ = try self.load(slice, Type.usize, 0);
// calculate index into slice
try self.emitWValue(index);
try self.addImm32(@bitCast(i32, @intCast(u32, elem_size)));
try self.addTag(.i32_mul);
try self.addTag(.i32_add);
const result = try self.allocLocal(Type.i32);
try self.addLabel(.local_set, result.local);
return result;
}
fn airSlicePtr(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const ty_op = self.air.instructions.items(.data)[inst].ty_op;
const operand = try self.resolveInst(ty_op.operand);
const ptr = try self.load(operand, Type.usize, 0);
return ptr.toLocal(self, Type.usize);
}
fn airTrunc(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const ty_op = self.air.instructions.items(.data)[inst].ty_op;
const operand = try self.resolveInst(ty_op.operand);
const wanted_ty = self.air.getRefType(ty_op.ty);
const op_ty = self.air.typeOf(ty_op.operand);
const int_info = op_ty.intInfo(self.target);
if (toWasmBits(int_info.bits) == null) {
return self.fail("TODO: Implement wasm integer truncation for integer bitsize: {d}", .{int_info.bits});
}
var result = try self.intcast(operand, op_ty, wanted_ty);
const wanted_bits = wanted_ty.intInfo(self.target).bits;
const wasm_bits = toWasmBits(wanted_bits).?;
if (wasm_bits != wanted_bits) {
result = try self.wrapOperand(result, wanted_ty);
}
return result.toLocal(self, wanted_ty);
}
fn airBoolToInt(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
const un_op = self.air.instructions.items(.data)[inst].un_op;
return self.resolveInst(un_op);
}
fn airArrayToSlice(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
const ty_op = self.air.instructions.items(.data)[inst].ty_op;
const operand = try self.resolveInst(ty_op.operand);
const array_ty = self.air.typeOf(ty_op.operand).childType();
const slice_ty = self.air.getRefType(ty_op.ty);
// create a slice on the stack
const slice_local = try self.allocStack(slice_ty);
// store the array ptr in the slice
if (array_ty.hasRuntimeBitsIgnoreComptime()) {
try self.store(slice_local, operand, Type.usize, 0);
}
// store the length of the array in the slice
const len = WValue{ .imm32 = @intCast(u32, array_ty.arrayLen()) };
try self.store(slice_local, len, Type.usize, self.ptrSize());
return slice_local;
}
fn airPtrToInt(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const un_op = self.air.instructions.items(.data)[inst].un_op;
const operand = try self.resolveInst(un_op);
switch (operand) {
// for stack offset, return a pointer to this offset.
.stack_offset => return self.buildPointerOffset(operand, 0, .new),
else => return operand,
}
}
fn airPtrElemVal(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const bin_op = self.air.instructions.items(.data)[inst].bin_op;
const ptr_ty = self.air.typeOf(bin_op.lhs);
const ptr = try self.resolveInst(bin_op.lhs);
const index = try self.resolveInst(bin_op.rhs);
const elem_ty = ptr_ty.childType();
const elem_size = elem_ty.abiSize(self.target);
// load pointer onto the stack
if (ptr_ty.isSlice()) {
_ = try self.load(ptr, Type.usize, 0);
} else {
try self.lowerToStack(ptr);
}
// calculate index into slice
try self.emitWValue(index);
try self.addImm32(@bitCast(i32, @intCast(u32, elem_size)));
try self.addTag(.i32_mul);
try self.addTag(.i32_add);
var result = try self.allocLocal(elem_ty);
try self.addLabel(.local_set, result.local);
if (isByRef(elem_ty, self.target)) {
return result;
}
defer result.free(self); // only free if it's not returned like above
const elem_val = try self.load(result, elem_ty, 0);
return elem_val.toLocal(self, elem_ty);
}
fn airPtrElemPtr(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const ty_pl = self.air.instructions.items(.data)[inst].ty_pl;
const bin_op = self.air.extraData(Air.Bin, ty_pl.payload).data;
const ptr_ty = self.air.typeOf(bin_op.lhs);
const elem_ty = self.air.getRefType(ty_pl.ty).childType();
const elem_size = elem_ty.abiSize(self.target);
const ptr = try self.resolveInst(bin_op.lhs);
const index = try self.resolveInst(bin_op.rhs);
// load pointer onto the stack
if (ptr_ty.isSlice()) {
_ = try self.load(ptr, Type.usize, 0);
} else {
try self.lowerToStack(ptr);
}
// calculate index into ptr
try self.emitWValue(index);
try self.addImm32(@bitCast(i32, @intCast(u32, elem_size)));
try self.addTag(.i32_mul);
try self.addTag(.i32_add);
const result = try self.allocLocal(Type.i32);
try self.addLabel(.local_set, result.local);
return result;
}
fn airPtrBinOp(self: *Self, inst: Air.Inst.Index, op: Op) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const ty_pl = self.air.instructions.items(.data)[inst].ty_pl;
const bin_op = self.air.extraData(Air.Bin, ty_pl.payload).data;
const ptr = try self.resolveInst(bin_op.lhs);
const offset = try self.resolveInst(bin_op.rhs);
const ptr_ty = self.air.typeOf(bin_op.lhs);
const pointee_ty = switch (ptr_ty.ptrSize()) {
.One => ptr_ty.childType().childType(), // ptr to array, so get array element type
else => ptr_ty.childType(),
};
const valtype = typeToValtype(Type.usize, self.target);
const mul_opcode = buildOpcode(.{ .valtype1 = valtype, .op = .mul });
const bin_opcode = buildOpcode(.{ .valtype1 = valtype, .op = op });
try self.lowerToStack(ptr);
try self.emitWValue(offset);
try self.addImm32(@bitCast(i32, @intCast(u32, pointee_ty.abiSize(self.target))));
try self.addTag(Mir.Inst.Tag.fromOpcode(mul_opcode));
try self.addTag(Mir.Inst.Tag.fromOpcode(bin_opcode));
const result = try self.allocLocal(Type.usize);
try self.addLabel(.local_set, result.local);
return result;
}
fn airMemset(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
const pl_op = self.air.instructions.items(.data)[inst].pl_op;
const bin_op = self.air.extraData(Air.Bin, pl_op.payload).data;
const ptr = try self.resolveInst(pl_op.operand);
const value = try self.resolveInst(bin_op.lhs);
const len = try self.resolveInst(bin_op.rhs);
try self.memset(ptr, len, value);
return WValue{ .none = {} };
}
/// Sets a region of memory at `ptr` to the value of `value`
/// When the user has enabled the bulk_memory feature, we lower
/// this to wasm's memset instruction. When the feature is not present,
/// we implement it manually.
fn memset(self: *Self, ptr: WValue, len: WValue, value: WValue) InnerError!void {
// When bulk_memory is enabled, we lower it to wasm's memset instruction.
// If not, we lower it ourselves
if (std.Target.wasm.featureSetHas(self.target.cpu.features, .bulk_memory)) {
try self.lowerToStack(ptr);
try self.emitWValue(value);
try self.emitWValue(len);
try self.addExtended(.memory_fill);
return;
}
// When the length is comptime-known we do the loop at codegen, rather
// than emitting a runtime loop into the binary
switch (len) {
.imm32, .imm64 => {
const length = switch (len) {
.imm32 => |val| val,
.imm64 => |val| val,
else => unreachable,
};
var offset: u32 = 0;
const base = ptr.offset();
while (offset < length) : (offset += 1) {
try self.emitWValue(ptr);
try self.emitWValue(value);
switch (self.arch()) {
.wasm32 => {
try self.addMemArg(.i32_store8, .{ .offset = base + offset, .alignment = 1 });
},
.wasm64 => {
try self.addMemArg(.i64_store8, .{ .offset = base + offset, .alignment = 1 });
},
else => unreachable,
}
}
},
else => {
// TODO: We should probably lower this to a call to compiler_rt
// But for now, we implement it manually
const offset = try self.ensureAllocLocal(Type.usize); // local for counter
// outer block to jump to when loop is done
try self.startBlock(.block, wasm.block_empty);
try self.startBlock(.loop, wasm.block_empty);
try self.emitWValue(offset);
try self.emitWValue(len);
switch (self.arch()) {
.wasm32 => try self.addTag(.i32_eq),
.wasm64 => try self.addTag(.i64_eq),
else => unreachable,
}
try self.addLabel(.br_if, 1); // jump out of loop into outer block (finished)
try self.emitWValue(ptr);
try self.emitWValue(offset);
switch (self.arch()) {
.wasm32 => try self.addTag(.i32_add),
.wasm64 => try self.addTag(.i64_add),
else => unreachable,
}
try self.emitWValue(value);
const mem_store_op: Mir.Inst.Tag = switch (self.arch()) {
.wasm32 => .i32_store8,
.wasm64 => .i64_store8,
else => unreachable,
};
try self.addMemArg(mem_store_op, .{ .offset = ptr.offset(), .alignment = 1 });
try self.emitWValue(offset);
try self.addImm32(1);
switch (self.arch()) {
.wasm32 => try self.addTag(.i32_add),
.wasm64 => try self.addTag(.i64_add),
else => unreachable,
}
try self.addLabel(.local_set, offset.local);
try self.addLabel(.br, 0); // jump to start of loop
try self.endBlock();
try self.endBlock();
},
}
}
fn airArrayElemVal(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const bin_op = self.air.instructions.items(.data)[inst].bin_op;
const array_ty = self.air.typeOf(bin_op.lhs);
const array = try self.resolveInst(bin_op.lhs);
const index = try self.resolveInst(bin_op.rhs);
const elem_ty = array_ty.childType();
const elem_size = elem_ty.abiSize(self.target);
try self.lowerToStack(array);
try self.emitWValue(index);
try self.addImm32(@bitCast(i32, @intCast(u32, elem_size)));
try self.addTag(.i32_mul);
try self.addTag(.i32_add);
var result = try self.allocLocal(Type.usize);
try self.addLabel(.local_set, result.local);
if (isByRef(elem_ty, self.target)) {
return result;
}
defer result.free(self); // only free if no longer needed and not returned like above
const elem_val = try self.load(result, elem_ty, 0);
return elem_val.toLocal(self, elem_ty);
}
fn airFloatToInt(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const ty_op = self.air.instructions.items(.data)[inst].ty_op;
const operand = try self.resolveInst(ty_op.operand);
const dest_ty = self.air.typeOfIndex(inst);
const op_ty = self.air.typeOf(ty_op.operand);
if (op_ty.abiSize(self.target) > 8) {
return self.fail("TODO: floatToInt for integers/floats with bitsize larger than 64 bits", .{});
}
try self.emitWValue(operand);
const op = buildOpcode(.{
.op = .trunc,
.valtype1 = typeToValtype(dest_ty, self.target),
.valtype2 = typeToValtype(op_ty, self.target),
.signedness = if (dest_ty.isSignedInt()) .signed else .unsigned,
});
try self.addTag(Mir.Inst.Tag.fromOpcode(op));
const wrapped = try self.wrapOperand(.{ .stack = {} }, dest_ty);
return wrapped.toLocal(self, dest_ty);
}
fn airIntToFloat(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const ty_op = self.air.instructions.items(.data)[inst].ty_op;
const operand = try self.resolveInst(ty_op.operand);
const dest_ty = self.air.typeOfIndex(inst);
const op_ty = self.air.typeOf(ty_op.operand);
if (op_ty.abiSize(self.target) > 8) {
return self.fail("TODO: intToFloat for integers/floats with bitsize larger than 64 bits", .{});
}
try self.emitWValue(operand);
const op = buildOpcode(.{
.op = .convert,
.valtype1 = typeToValtype(dest_ty, self.target),
.valtype2 = typeToValtype(op_ty, self.target),
.signedness = if (op_ty.isSignedInt()) .signed else .unsigned,
});
try self.addTag(Mir.Inst.Tag.fromOpcode(op));
const result = try self.allocLocal(dest_ty);
try self.addLabel(.local_set, result.local);
return result;
}
fn airSplat(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const ty_op = self.air.instructions.items(.data)[inst].ty_op;
const operand = try self.resolveInst(ty_op.operand);
_ = operand;
return self.fail("TODO: Implement wasm airSplat", .{});
}
fn airSelect(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const pl_op = self.air.instructions.items(.data)[inst].pl_op;
const operand = try self.resolveInst(pl_op.operand);
_ = operand;
return self.fail("TODO: Implement wasm airSelect", .{});
}
fn airShuffle(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const ty_op = self.air.instructions.items(.data)[inst].ty_op;
const operand = try self.resolveInst(ty_op.operand);
_ = operand;
return self.fail("TODO: Implement wasm airShuffle", .{});
}
fn airReduce(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const reduce = self.air.instructions.items(.data)[inst].reduce;
const operand = try self.resolveInst(reduce.operand);
_ = operand;
return self.fail("TODO: Implement wasm airReduce", .{});
}
fn airAggregateInit(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const ty_pl = self.air.instructions.items(.data)[inst].ty_pl;
const result_ty = self.air.typeOfIndex(inst);
const len = @intCast(usize, result_ty.arrayLen());
const elements = @ptrCast([]const Air.Inst.Ref, self.air.extra[ty_pl.payload..][0..len]);
switch (result_ty.zigTypeTag()) {
.Vector => return self.fail("TODO: Wasm backend: implement airAggregateInit for vectors", .{}),
.Array => {
const result = try self.allocStack(result_ty);
const elem_ty = result_ty.childType();
const elem_size = @intCast(u32, elem_ty.abiSize(self.target));
// When the element type is by reference, we must copy the entire
// value. It is therefore safer to move the offset pointer and store
// each value individually, instead of using store offsets.
if (isByRef(elem_ty, self.target)) {
// copy stack pointer into a temporary local, which is
// moved for each element to store each value in the right position.
const offset = try self.buildPointerOffset(result, 0, .new);
for (elements) |elem, elem_index| {
const elem_val = try self.resolveInst(elem);
try self.store(offset, elem_val, elem_ty, 0);
if (elem_index < elements.len - 1) {
_ = try self.buildPointerOffset(offset, elem_size, .modify);
}
}
} else {
var offset: u32 = 0;
for (elements) |elem| {
const elem_val = try self.resolveInst(elem);
try self.store(result, elem_val, elem_ty, offset);
offset += elem_size;
}
}
return result;
},
.Struct => {
const result = try self.allocStack(result_ty);
const offset = try self.buildPointerOffset(result, 0, .new); // pointer to offset
for (elements) |elem, elem_index| {
if (result_ty.structFieldValueComptime(elem_index) != null) continue;
const elem_ty = result_ty.structFieldType(elem_index);
const elem_size = @intCast(u32, elem_ty.abiSize(self.target));
const value = try self.resolveInst(elem);
try self.store(offset, value, elem_ty, 0);
if (elem_index < elements.len - 1) {
_ = try self.buildPointerOffset(offset, elem_size, .modify);
}
}
return result;
},
else => unreachable,
}
}
fn airUnionInit(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const ty_pl = self.air.instructions.items(.data)[inst].ty_pl;
const extra = self.air.extraData(Air.UnionInit, ty_pl.payload).data;
const union_ty = self.air.typeOfIndex(inst);
const layout = union_ty.unionGetLayout(self.target);
if (layout.payload_size == 0) {
if (layout.tag_size == 0) {
return WValue{ .none = {} };
}
assert(!isByRef(union_ty, self.target));
return WValue{ .imm32 = extra.field_index };
}
assert(isByRef(union_ty, self.target));
const result_ptr = try self.allocStack(union_ty);
const payload = try self.resolveInst(extra.init);
const union_obj = union_ty.cast(Type.Payload.Union).?.data;
assert(union_obj.haveFieldTypes());
const field = union_obj.fields.values()[extra.field_index];
if (layout.tag_align >= layout.payload_align) {
const payload_ptr = try self.buildPointerOffset(result_ptr, layout.tag_size, .new);
try self.store(payload_ptr, payload, field.ty, 0);
} else {
try self.store(result_ptr, payload, field.ty, 0);
}
return result_ptr;
}
fn airPrefetch(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
const prefetch = self.air.instructions.items(.data)[inst].prefetch;
_ = prefetch;
return WValue{ .none = {} };
}
fn airWasmMemorySize(self: *Self, inst: Air.Inst.Index) !WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const pl_op = self.air.instructions.items(.data)[inst].pl_op;
const result = try self.allocLocal(self.air.typeOfIndex(inst));
try self.addLabel(.memory_size, pl_op.payload);
try self.addLabel(.local_set, result.local);
return result;
}
fn airWasmMemoryGrow(self: *Self, inst: Air.Inst.Index) !WValue {
const pl_op = self.air.instructions.items(.data)[inst].pl_op;
const operand = try self.resolveInst(pl_op.operand);
const result = try self.allocLocal(self.air.typeOfIndex(inst));
try self.emitWValue(operand);
try self.addLabel(.memory_grow, pl_op.payload);
try self.addLabel(.local_set, result.local);
return result;
}
fn cmpOptionals(self: *Self, lhs: WValue, rhs: WValue, operand_ty: Type, op: std.math.CompareOperator) InnerError!WValue {
assert(operand_ty.hasRuntimeBitsIgnoreComptime());
assert(op == .eq or op == .neq);
var buf: Type.Payload.ElemType = undefined;
const payload_ty = operand_ty.optionalChild(&buf);
const offset = @intCast(u32, operand_ty.abiSize(self.target) - payload_ty.abiSize(self.target));
// We store the final result in here that will be validated
// if the optional is truly equal.
var result = try self.ensureAllocLocal(Type.initTag(.i32));
defer result.free(self);
try self.startBlock(.block, wasm.block_empty);
_ = try self.isNull(lhs, operand_ty, .i32_eq);
_ = try self.isNull(rhs, operand_ty, .i32_eq);
try self.addTag(.i32_ne); // inverse so we can exit early
try self.addLabel(.br_if, 0);
_ = try self.load(lhs, payload_ty, offset);
_ = try self.load(rhs, payload_ty, offset);
const opcode = buildOpcode(.{ .op = .ne, .valtype1 = typeToValtype(payload_ty, self.target) });
try self.addTag(Mir.Inst.Tag.fromOpcode(opcode));
try self.addLabel(.br_if, 0);
try self.addImm32(1);
try self.addLabel(.local_set, result.local);
try self.endBlock();
try self.emitWValue(result);
try self.addImm32(0);
try self.addTag(if (op == .eq) .i32_ne else .i32_eq);
return WValue{ .stack = {} };
}
/// Compares big integers by checking both its high bits and low bits.
/// NOTE: Leaves the result of the comparison on top of the stack.
/// TODO: Lower this to compiler_rt call when bitsize > 128
fn cmpBigInt(self: *Self, lhs: WValue, rhs: WValue, operand_ty: Type, op: std.math.CompareOperator) InnerError!WValue {
assert(operand_ty.abiSize(self.target) >= 16);
assert(!(lhs != .stack and rhs == .stack));
if (operand_ty.intInfo(self.target).bits > 128) {
return self.fail("TODO: Support cmpBigInt for integer bitsize: '{d}'", .{operand_ty.intInfo(self.target).bits});
}
var lhs_high_bit = try (try self.load(lhs, Type.u64, 0)).toLocal(self, Type.u64);
defer lhs_high_bit.free(self);
var rhs_high_bit = try (try self.load(rhs, Type.u64, 0)).toLocal(self, Type.u64);
defer rhs_high_bit.free(self);
switch (op) {
.eq, .neq => {
const xor_high = try self.binOp(lhs_high_bit, rhs_high_bit, Type.u64, .xor);
const lhs_low_bit = try self.load(lhs, Type.u64, 8);
const rhs_low_bit = try self.load(rhs, Type.u64, 8);
const xor_low = try self.binOp(lhs_low_bit, rhs_low_bit, Type.u64, .xor);
const or_result = try self.binOp(xor_high, xor_low, Type.u64, .@"or");
switch (op) {
.eq => return self.cmp(or_result, .{ .imm64 = 0 }, Type.u64, .eq),
.neq => return self.cmp(or_result, .{ .imm64 = 0 }, Type.u64, .neq),
else => unreachable,
}
},
else => {
const ty = if (operand_ty.isSignedInt()) Type.i64 else Type.u64;
// leave those value on top of the stack for '.select'
const lhs_low_bit = try self.load(lhs, Type.u64, 8);
const rhs_low_bit = try self.load(rhs, Type.u64, 8);
_ = try self.cmp(lhs_low_bit, rhs_low_bit, ty, op);
_ = try self.cmp(lhs_high_bit, rhs_high_bit, ty, op);
_ = try self.cmp(lhs_high_bit, rhs_high_bit, ty, .eq);
try self.addTag(.select);
},
}
return WValue{ .stack = {} };
}
fn airSetUnionTag(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
const bin_op = self.air.instructions.items(.data)[inst].bin_op;
const un_ty = self.air.typeOf(bin_op.lhs).childType();
const tag_ty = self.air.typeOf(bin_op.rhs);
const layout = un_ty.unionGetLayout(self.target);
if (layout.tag_size == 0) return WValue{ .none = {} };
const union_ptr = try self.resolveInst(bin_op.lhs);
const new_tag = try self.resolveInst(bin_op.rhs);
if (layout.payload_size == 0) {
try self.store(union_ptr, new_tag, tag_ty, 0);
return WValue{ .none = {} };
}
// when the tag alignment is smaller than the payload, the field will be stored
// after the payload.
const offset = if (layout.tag_align < layout.payload_align) blk: {
break :blk @intCast(u32, layout.payload_size);
} else @as(u32, 0);
try self.store(union_ptr, new_tag, tag_ty, offset);
return WValue{ .none = {} };
}
fn airGetUnionTag(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const ty_op = self.air.instructions.items(.data)[inst].ty_op;
const un_ty = self.air.typeOf(ty_op.operand);
const tag_ty = self.air.typeOfIndex(inst);
const layout = un_ty.unionGetLayout(self.target);
if (layout.tag_size == 0) return WValue{ .none = {} };
const operand = try self.resolveInst(ty_op.operand);
// when the tag alignment is smaller than the payload, the field will be stored
// after the payload.
const offset = if (layout.tag_align < layout.payload_align) blk: {
break :blk @intCast(u32, layout.payload_size);
} else @as(u32, 0);
const tag = try self.load(operand, tag_ty, offset);
return tag.toLocal(self, tag_ty);
}
fn airFpext(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const ty_op = self.air.instructions.items(.data)[inst].ty_op;
const dest_ty = self.air.typeOfIndex(inst);
const operand = try self.resolveInst(ty_op.operand);
const extended = try self.fpext(operand, self.air.typeOf(ty_op.operand), dest_ty);
return extended.toLocal(self, dest_ty);
}
/// Extends a float from a given `Type` to a larger wanted `Type`
/// NOTE: Leaves the result on the stack
fn fpext(self: *Self, operand: WValue, given: Type, wanted: Type) InnerError!WValue {
const given_bits = given.floatBits(self.target);
const wanted_bits = wanted.floatBits(self.target);
if (wanted_bits == 64 and given_bits == 32) {
try self.emitWValue(operand);
try self.addTag(.f64_promote_f32);
return WValue{ .stack = {} };
} else if (given_bits == 16) {
// call __extendhfsf2(f16) f32
const f32_result = try self.callIntrinsic(
"__extendhfsf2",
&.{Type.f16},
Type.f32,
&.{operand},
);
if (wanted_bits == 32) {
return f32_result;
}
if (wanted_bits == 64) {
try self.addTag(.f64_promote_f32);
return WValue{ .stack = {} };
}
return self.fail("TODO: Implement 'fpext' for floats with bitsize: {d}", .{wanted_bits});
} else {
// TODO: Emit a call to compiler-rt to extend the float. e.g. __extendhfsf2
return self.fail("TODO: Implement 'fpext' for floats with bitsize: {d}", .{wanted_bits});
}
}
fn airFptrunc(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const ty_op = self.air.instructions.items(.data)[inst].ty_op;
const dest_ty = self.air.typeOfIndex(inst);
const operand = try self.resolveInst(ty_op.operand);
const trunc = try self.fptrunc(operand, self.air.typeOf(ty_op.operand), dest_ty);
return trunc.toLocal(self, dest_ty);
}
/// Truncates a float from a given `Type` to its wanted `Type`
/// NOTE: The result value remains on the stack
fn fptrunc(self: *Self, operand: WValue, given: Type, wanted: Type) InnerError!WValue {
const given_bits = given.floatBits(self.target);
const wanted_bits = wanted.floatBits(self.target);
if (wanted_bits == 32 and given_bits == 64) {
try self.emitWValue(operand);
try self.addTag(.f32_demote_f64);
return WValue{ .stack = {} };
} else if (wanted_bits == 16) {
const op: WValue = if (given_bits == 64) blk: {
try self.emitWValue(operand);
try self.addTag(.f32_demote_f64);
break :blk WValue{ .stack = {} };
} else operand;
// call __truncsfhf2(f32) f16
return self.callIntrinsic("__truncsfhf2", &.{Type.f32}, Type.f16, &.{op});
} else {
// TODO: Emit a call to compiler-rt to trunc the float. e.g. __truncdfhf2
return self.fail("TODO: Implement 'fptrunc' for floats with bitsize: {d}", .{wanted_bits});
}
}
fn airErrUnionPayloadPtrSet(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
const ty_op = self.air.instructions.items(.data)[inst].ty_op;
const err_set_ty = self.air.typeOf(ty_op.operand).childType();
const payload_ty = err_set_ty.errorUnionPayload();
const operand = try self.resolveInst(ty_op.operand);
// set error-tag to '0' to annotate error union is non-error
try self.store(
operand,
.{ .imm32 = 0 },
Type.anyerror,
@intCast(u32, errUnionErrorOffset(payload_ty, self.target)),
);
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
if (!payload_ty.hasRuntimeBitsIgnoreComptime()) {
return operand;
}
return self.buildPointerOffset(operand, @intCast(u32, errUnionPayloadOffset(payload_ty, self.target)), .new);
}
fn airFieldParentPtr(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const ty_pl = self.air.instructions.items(.data)[inst].ty_pl;
const extra = self.air.extraData(Air.FieldParentPtr, ty_pl.payload).data;
const field_ptr = try self.resolveInst(extra.field_ptr);
const struct_ty = self.air.getRefType(ty_pl.ty).childType();
const field_offset = struct_ty.structFieldOffset(extra.field_index, self.target);
if (field_offset == 0) {
return field_ptr;
}
const base = try self.buildPointerOffset(field_ptr, 0, .new);
try self.addLabel(.local_get, base.local);
try self.addImm32(@bitCast(i32, @intCast(u32, field_offset)));
try self.addTag(.i32_sub);
try self.addLabel(.local_set, base.local);
return base;
}
fn airMemcpy(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
const pl_op = self.air.instructions.items(.data)[inst].pl_op;
const bin_op = self.air.extraData(Air.Bin, pl_op.payload).data;
const dst = try self.resolveInst(pl_op.operand);
const src = try self.resolveInst(bin_op.lhs);
const len = try self.resolveInst(bin_op.rhs);
try self.memcpy(dst, src, len);
return WValue{ .none = {} };
}
fn airPopcount(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const ty_op = self.air.instructions.items(.data)[inst].ty_op;
const operand = try self.resolveInst(ty_op.operand);
const op_ty = self.air.typeOf(ty_op.operand);
const result_ty = self.air.typeOfIndex(inst);
if (op_ty.zigTypeTag() == .Vector) {
return self.fail("TODO: Implement @popCount for vectors", .{});
}
const int_info = op_ty.intInfo(self.target);
const bits = int_info.bits;
const wasm_bits = toWasmBits(bits) orelse {
return self.fail("TODO: Implement @popCount for integers with bitsize '{d}'", .{bits});
};
switch (wasm_bits) {
128 => {
_ = try self.load(operand, Type.u64, 0);
try self.addTag(.i64_popcnt);
_ = try self.load(operand, Type.u64, 8);
try self.addTag(.i64_popcnt);
try self.addTag(.i64_add);
try self.addTag(.i32_wrap_i64);
},
else => {
try self.emitWValue(operand);
switch (wasm_bits) {
32 => try self.addTag(.i32_popcnt),
64 => {
try self.addTag(.i64_popcnt);
try self.addTag(.i32_wrap_i64);
},
else => unreachable,
}
},
}
const result = try self.allocLocal(result_ty);
try self.addLabel(.local_set, result.local);
return result;
}
fn airErrorName(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const un_op = self.air.instructions.items(.data)[inst].un_op;
const operand = try self.resolveInst(un_op);
// First retrieve the symbol index to the error name table
// that will be used to emit a relocation for the pointer
// to the error name table.
//
// Each entry to this table is a slice (ptr+len).
// The operand in this instruction represents the index within this table.
// This means to get the final name, we emit the base pointer and then perform
// pointer arithmetic to find the pointer to this slice and return that.
//
// As the names are global and the slice elements are constant, we do not have
// to make a copy of the ptr+value but can point towards them directly.
const error_table_symbol = try self.bin_file.getErrorTableSymbol();
const name_ty = Type.initTag(.const_slice_u8_sentinel_0);
const abi_size = name_ty.abiSize(self.target);
const error_name_value: WValue = .{ .memory = error_table_symbol }; // emitting this will create a relocation
try self.emitWValue(error_name_value);
try self.emitWValue(operand);
switch (self.arch()) {
.wasm32 => {
try self.addImm32(@bitCast(i32, @intCast(u32, abi_size)));
try self.addTag(.i32_mul);
try self.addTag(.i32_add);
},
.wasm64 => {
try self.addImm64(abi_size);
try self.addTag(.i64_mul);
try self.addTag(.i64_add);
},
else => unreachable,
}
const result_ptr = try self.allocLocal(Type.usize);
try self.addLabel(.local_set, result_ptr.local);
return result_ptr;
}
fn airPtrSliceFieldPtr(self: *Self, inst: Air.Inst.Index, offset: u32) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const ty_op = self.air.instructions.items(.data)[inst].ty_op;
const slice_ptr = try self.resolveInst(ty_op.operand);
return self.buildPointerOffset(slice_ptr, offset, .new);
}
fn airAddSubWithOverflow(self: *Self, inst: Air.Inst.Index, op: Op) InnerError!WValue {
assert(op == .add or op == .sub);
const ty_pl = self.air.instructions.items(.data)[inst].ty_pl;
const extra = self.air.extraData(Air.Bin, ty_pl.payload).data;
const lhs_op = try self.resolveInst(extra.lhs);
const rhs_op = try self.resolveInst(extra.rhs);
const lhs_ty = self.air.typeOf(extra.lhs);
if (lhs_ty.zigTypeTag() == .Vector) {
return self.fail("TODO: Implement overflow arithmetic for vectors", .{});
}
const int_info = lhs_ty.intInfo(self.target);
const is_signed = int_info.signedness == .signed;
const wasm_bits = toWasmBits(int_info.bits) orelse {
return self.fail("TODO: Implement {{add/sub}}_with_overflow for integer bitsize: {d}", .{int_info.bits});
};
if (wasm_bits == 128) {
return self.airAddSubWithOverflowBigInt(lhs_op, rhs_op, lhs_ty, self.air.typeOfIndex(inst), op);
}
const zero = switch (wasm_bits) {
32 => WValue{ .imm32 = 0 },
64 => WValue{ .imm64 = 0 },
else => unreachable,
};
// for signed integers, we first apply signed shifts by the difference in bits
// to get the signed value, as we store it internally as 2's complement.
var lhs = if (wasm_bits != int_info.bits and is_signed) blk: {
break :blk try (try self.signAbsValue(lhs_op, lhs_ty)).toLocal(self, lhs_ty);
} else lhs_op;
var rhs = if (wasm_bits != int_info.bits and is_signed) blk: {
break :blk try (try self.signAbsValue(rhs_op, lhs_ty)).toLocal(self, lhs_ty);
} else rhs_op;
var bin_op = try (try self.binOp(lhs, rhs, lhs_ty, op)).toLocal(self, lhs_ty);
defer bin_op.free(self);
var result = if (wasm_bits != int_info.bits) blk: {
break :blk try (try self.wrapOperand(bin_op, lhs_ty)).toLocal(self, lhs_ty);
} else bin_op;
defer result.free(self); // no-op when wasm_bits == int_info.bits
const cmp_op: std.math.CompareOperator = if (op == .sub) .gt else .lt;
const overflow_bit: WValue = if (is_signed) blk: {
if (wasm_bits == int_info.bits) {
const cmp_zero = try self.cmp(rhs, zero, lhs_ty, cmp_op);
const lt = try self.cmp(bin_op, lhs, lhs_ty, .lt);
break :blk try self.binOp(cmp_zero, lt, Type.u32, .xor);
}
const abs = try self.signAbsValue(bin_op, lhs_ty);
break :blk try self.cmp(abs, bin_op, lhs_ty, .neq);
} else if (wasm_bits == int_info.bits)
try self.cmp(bin_op, lhs, lhs_ty, cmp_op)
else
try self.cmp(bin_op, result, lhs_ty, .neq);
var overflow_local = try overflow_bit.toLocal(self, Type.u32);
defer overflow_local.free(self);
const result_ptr = try self.allocStack(self.air.typeOfIndex(inst));
try self.store(result_ptr, result, lhs_ty, 0);
const offset = @intCast(u32, lhs_ty.abiSize(self.target));
try self.store(result_ptr, overflow_local, Type.initTag(.u1), offset);
// in this case, we performed a signAbsValue which created a temporary local
// so let's free this so it can be re-used instead.
// In the other case we do not want to free it, because that would free the
// resolved instructions which may be referenced by other instructions.
if (wasm_bits != int_info.bits and is_signed) {
lhs.free(self);
rhs.free(self);
}
return result_ptr;
}
fn airAddSubWithOverflowBigInt(self: *Self, lhs: WValue, rhs: WValue, ty: Type, result_ty: Type, op: Op) InnerError!WValue {
assert(op == .add or op == .sub);
const int_info = ty.intInfo(self.target);
const is_signed = int_info.signedness == .signed;
if (int_info.bits != 128) {
return self.fail("TODO: Implement @{{add/sub}}WithOverflow for integer bitsize '{d}'", .{int_info.bits});
}
var lhs_high_bit = try (try self.load(lhs, Type.u64, 0)).toLocal(self, Type.u64);
defer lhs_high_bit.free(self);
var lhs_low_bit = try (try self.load(lhs, Type.u64, 8)).toLocal(self, Type.u64);
defer lhs_low_bit.free(self);
var rhs_high_bit = try (try self.load(rhs, Type.u64, 0)).toLocal(self, Type.u64);
defer rhs_high_bit.free(self);
var rhs_low_bit = try (try self.load(rhs, Type.u64, 8)).toLocal(self, Type.u64);
defer rhs_low_bit.free(self);
var low_op_res = try (try self.binOp(lhs_low_bit, rhs_low_bit, Type.u64, op)).toLocal(self, Type.u64);
defer low_op_res.free(self);
var high_op_res = try (try self.binOp(lhs_high_bit, rhs_high_bit, Type.u64, op)).toLocal(self, Type.u64);
defer high_op_res.free(self);
var lt = if (op == .add) blk: {
break :blk try (try self.cmp(high_op_res, lhs_high_bit, Type.u64, .lt)).toLocal(self, Type.u32);
} else if (op == .sub) blk: {
break :blk try (try self.cmp(lhs_high_bit, rhs_high_bit, Type.u64, .lt)).toLocal(self, Type.u32);
} else unreachable;
defer lt.free(self);
var tmp = try (try self.intcast(lt, Type.u32, Type.u64)).toLocal(self, Type.u64);
defer tmp.free(self);
var tmp_op = try (try self.binOp(low_op_res, tmp, Type.u64, op)).toLocal(self, Type.u64);
defer tmp_op.free(self);
const overflow_bit = if (is_signed) blk: {
const xor_low = try self.binOp(lhs_low_bit, rhs_low_bit, Type.u64, .xor);
const to_wrap = if (op == .add) wrap: {
break :wrap try self.binOp(xor_low, .{ .imm64 = ~@as(u64, 0) }, Type.u64, .xor);
} else xor_low;
const xor_op = try self.binOp(lhs_low_bit, tmp_op, Type.u64, .xor);
const wrap = try self.binOp(to_wrap, xor_op, Type.u64, .@"and");
break :blk try self.cmp(wrap, .{ .imm64 = 0 }, Type.i64, .lt); // i64 because signed
} else blk: {
const first_arg = if (op == .sub) arg: {
break :arg try self.cmp(high_op_res, lhs_high_bit, Type.u64, .gt);
} else lt;
try self.emitWValue(first_arg);
_ = try self.cmp(tmp_op, lhs_low_bit, Type.u64, if (op == .add) .lt else .gt);
_ = try self.cmp(tmp_op, lhs_low_bit, Type.u64, .eq);
try self.addTag(.select);
break :blk WValue{ .stack = {} };
};
var overflow_local = try overflow_bit.toLocal(self, Type.initTag(.u1));
defer overflow_local.free(self);
const result_ptr = try self.allocStack(result_ty);
try self.store(result_ptr, high_op_res, Type.u64, 0);
try self.store(result_ptr, tmp_op, Type.u64, 8);
try self.store(result_ptr, overflow_local, Type.initTag(.u1), 16);
return result_ptr;
}
fn airShlWithOverflow(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
const ty_pl = self.air.instructions.items(.data)[inst].ty_pl;
const extra = self.air.extraData(Air.Bin, ty_pl.payload).data;
const lhs = try self.resolveInst(extra.lhs);
const rhs = try self.resolveInst(extra.rhs);
const lhs_ty = self.air.typeOf(extra.lhs);
if (lhs_ty.zigTypeTag() == .Vector) {
return self.fail("TODO: Implement overflow arithmetic for vectors", .{});
}
const int_info = lhs_ty.intInfo(self.target);
const is_signed = int_info.signedness == .signed;
const wasm_bits = toWasmBits(int_info.bits) orelse {
return self.fail("TODO: Implement shl_with_overflow for integer bitsize: {d}", .{int_info.bits});
};
var shl = try (try self.binOp(lhs, rhs, lhs_ty, .shl)).toLocal(self, lhs_ty);
defer shl.free(self);
var result = if (wasm_bits != int_info.bits) blk: {
break :blk try (try self.wrapOperand(shl, lhs_ty)).toLocal(self, lhs_ty);
} else shl;
defer result.free(self); // it's a no-op to free the same local twice (when wasm_bits == int_info.bits)
const overflow_bit = if (wasm_bits != int_info.bits and is_signed) blk: {
// emit lhs to stack to we can keep 'wrapped' on the stack also
try self.emitWValue(lhs);
const abs = try self.signAbsValue(shl, lhs_ty);
const wrapped = try self.wrapBinOp(abs, rhs, lhs_ty, .shr);
break :blk try self.cmp(.{ .stack = {} }, wrapped, lhs_ty, .neq);
} else blk: {
try self.emitWValue(lhs);
const shr = try self.binOp(result, rhs, lhs_ty, .shr);
break :blk try self.cmp(.{ .stack = {} }, shr, lhs_ty, .neq);
};
var overflow_local = try overflow_bit.toLocal(self, Type.initTag(.u1));
defer overflow_local.free(self);
const result_ptr = try self.allocStack(self.air.typeOfIndex(inst));
try self.store(result_ptr, result, lhs_ty, 0);
const offset = @intCast(u32, lhs_ty.abiSize(self.target));
try self.store(result_ptr, overflow_local, Type.initTag(.u1), offset);
return result_ptr;
}
fn airMulWithOverflow(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
const ty_pl = self.air.instructions.items(.data)[inst].ty_pl;
const extra = self.air.extraData(Air.Bin, ty_pl.payload).data;
const lhs = try self.resolveInst(extra.lhs);
const rhs = try self.resolveInst(extra.rhs);
const lhs_ty = self.air.typeOf(extra.lhs);
if (lhs_ty.zigTypeTag() == .Vector) {
return self.fail("TODO: Implement overflow arithmetic for vectors", .{});
}
// We store the bit if it's overflowed or not in this. As it's zero-initialized
// we only need to update it if an overflow (or underflow) occurred.
var overflow_bit = try self.ensureAllocLocal(Type.initTag(.u1));
defer overflow_bit.free(self);
const int_info = lhs_ty.intInfo(self.target);
const wasm_bits = toWasmBits(int_info.bits) orelse {
return self.fail("TODO: Implement overflow arithmetic for integer bitsize: {d}", .{int_info.bits});
};
if (wasm_bits > 32) {
return self.fail("TODO: Implement `@mulWithOverflow` for integer bitsize: {d}", .{int_info.bits});
}
const zero = switch (wasm_bits) {
32 => WValue{ .imm32 = 0 },
64 => WValue{ .imm64 = 0 },
else => unreachable,
};
// for 32 bit integers we upcast it to a 64bit integer
const bin_op = if (int_info.bits == 32) blk: {
const new_ty = if (int_info.signedness == .signed) Type.i64 else Type.u64;
const lhs_upcast = try self.intcast(lhs, lhs_ty, new_ty);
const rhs_upcast = try self.intcast(rhs, lhs_ty, new_ty);
const bin_op = try (try self.binOp(lhs_upcast, rhs_upcast, new_ty, .mul)).toLocal(self, new_ty);
if (int_info.signedness == .unsigned) {
const shr = try self.binOp(bin_op, .{ .imm64 = int_info.bits }, new_ty, .shr);
const wrap = try self.intcast(shr, new_ty, lhs_ty);
_ = try self.cmp(wrap, zero, lhs_ty, .neq);
try self.addLabel(.local_set, overflow_bit.local);
break :blk try self.intcast(bin_op, new_ty, lhs_ty);
} else {
const down_cast = try (try self.intcast(bin_op, new_ty, lhs_ty)).toLocal(self, lhs_ty);
var shr = try (try self.binOp(down_cast, .{ .imm32 = int_info.bits - 1 }, lhs_ty, .shr)).toLocal(self, lhs_ty);
defer shr.free(self);
const shr_res = try self.binOp(bin_op, .{ .imm64 = int_info.bits }, new_ty, .shr);
const down_shr_res = try self.intcast(shr_res, new_ty, lhs_ty);
_ = try self.cmp(down_shr_res, shr, lhs_ty, .neq);
try self.addLabel(.local_set, overflow_bit.local);
break :blk down_cast;
}
} else if (int_info.signedness == .signed) blk: {
const lhs_abs = try self.signAbsValue(lhs, lhs_ty);
const rhs_abs = try self.signAbsValue(rhs, lhs_ty);
const bin_op = try (try self.binOp(lhs_abs, rhs_abs, lhs_ty, .mul)).toLocal(self, lhs_ty);
const mul_abs = try self.signAbsValue(bin_op, lhs_ty);
_ = try self.cmp(mul_abs, bin_op, lhs_ty, .neq);
try self.addLabel(.local_set, overflow_bit.local);
break :blk try self.wrapOperand(bin_op, lhs_ty);
} else blk: {
var bin_op = try (try self.binOp(lhs, rhs, lhs_ty, .mul)).toLocal(self, lhs_ty);
defer bin_op.free(self);
const shift_imm = if (wasm_bits == 32)
WValue{ .imm32 = int_info.bits }
else
WValue{ .imm64 = int_info.bits };
const shr = try self.binOp(bin_op, shift_imm, lhs_ty, .shr);
_ = try self.cmp(shr, zero, lhs_ty, .neq);
try self.addLabel(.local_set, overflow_bit.local);
break :blk try self.wrapOperand(bin_op, lhs_ty);
};
var bin_op_local = try bin_op.toLocal(self, lhs_ty);
defer bin_op_local.free(self);
const result_ptr = try self.allocStack(self.air.typeOfIndex(inst));
try self.store(result_ptr, bin_op_local, lhs_ty, 0);
const offset = @intCast(u32, lhs_ty.abiSize(self.target));
try self.store(result_ptr, overflow_bit, Type.initTag(.u1), offset);
return result_ptr;
}
fn airMaxMin(self: *Self, inst: Air.Inst.Index, op: enum { max, min }) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const bin_op = self.air.instructions.items(.data)[inst].bin_op;
const ty = self.air.typeOfIndex(inst);
if (ty.zigTypeTag() == .Vector) {
return self.fail("TODO: `@maximum` and `@minimum` for vectors", .{});
}
if (ty.abiSize(self.target) > 16) {
return self.fail("TODO: `@maximum` and `@minimum` for types larger than 16 bytes", .{});
}
const lhs = try self.resolveInst(bin_op.lhs);
const rhs = try self.resolveInst(bin_op.rhs);
// operands to select from
try self.lowerToStack(lhs);
try self.lowerToStack(rhs);
_ = try self.cmp(lhs, rhs, ty, if (op == .max) .gt else .lt);
// based on the result from comparison, return operand 0 or 1.
try self.addTag(.select);
// store result in local
const result_ty = if (isByRef(ty, self.target)) Type.u32 else ty;
const result = try self.allocLocal(result_ty);
try self.addLabel(.local_set, result.local);
return result;
}
fn airMulAdd(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const pl_op = self.air.instructions.items(.data)[inst].pl_op;
const bin_op = self.air.extraData(Air.Bin, pl_op.payload).data;
const ty = self.air.typeOfIndex(inst);
if (ty.zigTypeTag() == .Vector) {
return self.fail("TODO: `@mulAdd` for vectors", .{});
}
const addend = try self.resolveInst(pl_op.operand);
const lhs = try self.resolveInst(bin_op.lhs);
const rhs = try self.resolveInst(bin_op.rhs);
if (ty.floatBits(self.target) == 16) {
const rhs_ext = try self.fpext(rhs, ty, Type.f32);
const lhs_ext = try self.fpext(lhs, ty, Type.f32);
const addend_ext = try self.fpext(addend, ty, Type.f32);
// call to compiler-rt `fn fmaf(f32, f32, f32) f32`
var result = try self.callIntrinsic(
"fmaf",
&.{ Type.f32, Type.f32, Type.f32 },
Type.f32,
&.{ rhs_ext, lhs_ext, addend_ext },
);
return try (try self.fptrunc(result, Type.f32, ty)).toLocal(self, ty);
}
const mul_result = try self.binOp(lhs, rhs, ty, .mul);
return (try self.binOp(mul_result, addend, ty, .add)).toLocal(self, ty);
}
fn airClz(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const ty_op = self.air.instructions.items(.data)[inst].ty_op;
const ty = self.air.typeOf(ty_op.operand);
const result_ty = self.air.typeOfIndex(inst);
if (ty.zigTypeTag() == .Vector) {
return self.fail("TODO: `@clz` for vectors", .{});
}
const operand = try self.resolveInst(ty_op.operand);
const int_info = ty.intInfo(self.target);
const wasm_bits = toWasmBits(int_info.bits) orelse {
return self.fail("TODO: `@clz` for integers with bitsize '{d}'", .{int_info.bits});
};
switch (wasm_bits) {
32 => {
try self.emitWValue(operand);
try self.addTag(.i32_clz);
},
64 => {
try self.emitWValue(operand);
try self.addTag(.i64_clz);
try self.addTag(.i32_wrap_i64);
},
128 => {
var lsb = try (try self.load(operand, Type.u64, 8)).toLocal(self, Type.u64);
defer lsb.free(self);
try self.emitWValue(lsb);
try self.addTag(.i64_clz);
_ = try self.load(operand, Type.u64, 0);
try self.addTag(.i64_clz);
try self.emitWValue(.{ .imm64 = 64 });
try self.addTag(.i64_add);
_ = try self.cmp(lsb, .{ .imm64 = 0 }, Type.u64, .neq);
try self.addTag(.select);
try self.addTag(.i32_wrap_i64);
},
else => unreachable,
}
if (wasm_bits != int_info.bits) {
try self.emitWValue(.{ .imm32 = wasm_bits - int_info.bits });
try self.addTag(.i32_sub);
}
const result = try self.allocLocal(result_ty);
try self.addLabel(.local_set, result.local);
return result;
}
fn airCtz(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const ty_op = self.air.instructions.items(.data)[inst].ty_op;
const ty = self.air.typeOf(ty_op.operand);
const result_ty = self.air.typeOfIndex(inst);
if (ty.zigTypeTag() == .Vector) {
return self.fail("TODO: `@ctz` for vectors", .{});
}
const operand = try self.resolveInst(ty_op.operand);
const int_info = ty.intInfo(self.target);
const wasm_bits = toWasmBits(int_info.bits) orelse {
return self.fail("TODO: `@clz` for integers with bitsize '{d}'", .{int_info.bits});
};
switch (wasm_bits) {
32 => {
if (wasm_bits != int_info.bits) {
const val: u32 = @as(u32, 1) << @intCast(u5, int_info.bits);
// leave value on the stack
_ = try self.binOp(operand, .{ .imm32 = val }, ty, .@"or");
} else try self.emitWValue(operand);
try self.addTag(.i32_ctz);
},
64 => {
if (wasm_bits != int_info.bits) {
const val: u64 = @as(u64, 1) << @intCast(u6, int_info.bits);
// leave value on the stack
_ = try self.binOp(operand, .{ .imm64 = val }, ty, .@"or");
} else try self.emitWValue(operand);
try self.addTag(.i64_ctz);
try self.addTag(.i32_wrap_i64);
},
128 => {
var msb = try (try self.load(operand, Type.u64, 0)).toLocal(self, Type.u64);
defer msb.free(self);
try self.emitWValue(msb);
try self.addTag(.i64_ctz);
_ = try self.load(operand, Type.u64, 8);
if (wasm_bits != int_info.bits) {
try self.addImm64(@as(u64, 1) << @intCast(u6, int_info.bits - 64));
try self.addTag(.i64_or);
}
try self.addTag(.i64_ctz);
try self.addImm64(64);
if (wasm_bits != int_info.bits) {
try self.addTag(.i64_or);
} else {
try self.addTag(.i64_add);
}
_ = try self.cmp(msb, .{ .imm64 = 0 }, Type.u64, .neq);
try self.addTag(.select);
try self.addTag(.i32_wrap_i64);
},
else => unreachable,
}
const result = try self.allocLocal(result_ty);
try self.addLabel(.local_set, result.local);
return result;
}
fn airDbgVar(self: *Self, inst: Air.Inst.Index, is_ptr: bool) !WValue {
if (self.debug_output != .dwarf) return WValue{ .none = {} };
const pl_op = self.air.instructions.items(.data)[inst].pl_op;
const ty = self.air.typeOf(pl_op.operand);
const operand = try self.resolveInst(pl_op.operand);
const op_ty = if (is_ptr) ty.childType() else ty;
log.debug("airDbgVar: %{d}: {}, {}", .{ inst, op_ty.fmtDebug(), operand });
const name = self.air.nullTerminatedString(pl_op.payload);
log.debug(" var name = ({s})", .{name});
const dbg_info = &self.debug_output.dwarf.dbg_info;
try dbg_info.append(@enumToInt(link.File.Dwarf.AbbrevKind.variable));
switch (operand) {
.local => |local| {
const leb_size = link.File.Wasm.getULEB128Size(local);
try dbg_info.ensureUnusedCapacity(2 + leb_size);
// wasm locals are encoded as follow:
// DW_OP_WASM_location wasm-op
// where wasm-op is defined as
// wasm-op := wasm-local | wasm-global | wasm-operand_stack
// where wasm-local is encoded as
// wasm-local := 0x00 i:uleb128
dbg_info.appendSliceAssumeCapacity(&.{
std.dwarf.OP.WASM_location,
std.dwarf.OP.WASM_local,
});
leb.writeULEB128(dbg_info.writer(), local) catch unreachable;
},
else => {}, // TODO
}
try dbg_info.ensureUnusedCapacity(5 + name.len + 1);
try self.addDbgInfoTypeReloc(op_ty);
dbg_info.appendSliceAssumeCapacity(name);
dbg_info.appendAssumeCapacity(0);
return WValue{ .none = {} };
}
fn airDbgStmt(self: *Self, inst: Air.Inst.Index) !WValue {
if (self.debug_output != .dwarf) return WValue{ .none = {} };
const dbg_stmt = self.air.instructions.items(.data)[inst].dbg_stmt;
try self.addInst(.{ .tag = .dbg_line, .data = .{
.payload = try self.addExtra(Mir.DbgLineColumn{
.line = dbg_stmt.line,
.column = dbg_stmt.column,
}),
} });
return WValue{ .none = {} };
}
fn airTry(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
const pl_op = self.air.instructions.items(.data)[inst].pl_op;
const err_union = try self.resolveInst(pl_op.operand);
const extra = self.air.extraData(Air.Try, pl_op.payload);
const body = self.air.extra[extra.end..][0..extra.data.body_len];
const err_union_ty = self.air.typeOf(pl_op.operand);
return lowerTry(self, err_union, body, err_union_ty, false);
}
fn airTryPtr(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
const ty_pl = self.air.instructions.items(.data)[inst].ty_pl;
const extra = self.air.extraData(Air.TryPtr, ty_pl.payload);
const err_union_ptr = try self.resolveInst(extra.data.ptr);
const body = self.air.extra[extra.end..][0..extra.data.body_len];
const err_union_ty = self.air.typeOf(extra.data.ptr).childType();
return lowerTry(self, err_union_ptr, body, err_union_ty, true);
}
fn lowerTry(
self: *Self,
err_union: WValue,
body: []const Air.Inst.Index,
err_union_ty: Type,
operand_is_ptr: bool,
) InnerError!WValue {
if (operand_is_ptr) {
return self.fail("TODO: lowerTry for pointers", .{});
}
const pl_ty = err_union_ty.errorUnionPayload();
const pl_has_bits = pl_ty.hasRuntimeBitsIgnoreComptime();
if (!err_union_ty.errorUnionSet().errorSetIsEmpty()) {
// Block we can jump out of when error is not set
try self.startBlock(.block, wasm.block_empty);
// check if the error tag is set for the error union.
try self.emitWValue(err_union);
if (pl_has_bits) {
const err_offset = @intCast(u32, errUnionErrorOffset(pl_ty, self.target));
try self.addMemArg(.i32_load16_u, .{
.offset = err_union.offset() + err_offset,
.alignment = Type.anyerror.abiAlignment(self.target),
});
}
try self.addTag(.i32_eqz);
try self.addLabel(.br_if, 0); // jump out of block when error is '0'
try self.genBody(body);
try self.endBlock();
}
// if we reach here it means error was not set, and we want the payload
if (!pl_has_bits) {
return WValue{ .none = {} };
}
const pl_offset = @intCast(u32, errUnionPayloadOffset(pl_ty, self.target));
if (isByRef(pl_ty, self.target)) {
return buildPointerOffset(self, err_union, pl_offset, .new);
}
const payload = try self.load(err_union, pl_ty, pl_offset);
return payload.toLocal(self, pl_ty);
}
fn airByteSwap(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
if (self.liveness.isUnused(inst)) {
return WValue{ .none = {} };
}
const ty_op = self.air.instructions.items(.data)[inst].ty_op;
const ty = self.air.typeOfIndex(inst);
const operand = try self.resolveInst(ty_op.operand);
if (ty.zigTypeTag() == .Vector) {
return self.fail("TODO: @byteSwap for vectors", .{});
}
const int_info = ty.intInfo(self.target);
// bytes are no-op
if (int_info.bits == 8) {
return operand;
}
switch (int_info.bits) {
16 => {
const shl_res = try self.binOp(operand, .{ .imm32 = 8 }, ty, .shl);
const lhs = try self.binOp(shl_res, .{ .imm32 = 0xFF00 }, ty, .@"and");
const shr_res = try self.binOp(operand, .{ .imm32 = 8 }, ty, .shr);
const res = if (int_info.signedness == .signed) blk: {
break :blk try self.wrapOperand(shr_res, Type.u8);
} else shr_res;
return (try self.binOp(lhs, res, ty, .@"or")).toLocal(self, ty);
},
24 => {
var msb = try (try self.wrapOperand(operand, Type.u16)).toLocal(self, Type.u16);
defer msb.free(self);
const shl_res = try self.binOp(msb, .{ .imm32 = 8 }, Type.u16, .shl);
const lhs = try self.binOp(shl_res, .{ .imm32 = 0xFF0000 }, Type.u16, .@"and");
const shr_res = try self.binOp(msb, .{ .imm32 = 8 }, ty, .shr);
const res = if (int_info.signedness == .signed) blk: {
break :blk try self.wrapOperand(shr_res, Type.u8);
} else shr_res;
const lhs_tmp = try self.binOp(lhs, res, ty, .@"or");
const lhs_result = try self.binOp(lhs_tmp, .{ .imm32 = 8 }, ty, .shr);
const rhs_wrap = try self.wrapOperand(msb, Type.u8);
const rhs_result = try self.binOp(rhs_wrap, .{ .imm32 = 16 }, ty, .shl);
const lsb = try self.wrapBinOp(operand, .{ .imm32 = 16 }, Type.u8, .shr);
const tmp = try self.binOp(lhs_result, rhs_result, ty, .@"or");
return (try self.binOp(tmp, lsb, ty, .@"or")).toLocal(self, ty);
},
32 => {
const shl_tmp = try self.binOp(operand, .{ .imm32 = 8 }, ty, .shl);
var lhs = try (try self.binOp(shl_tmp, .{ .imm32 = 0xFF00FF00 }, ty, .@"and")).toLocal(self, ty);
defer lhs.free(self);
const shr_tmp = try self.binOp(operand, .{ .imm32 = 8 }, ty, .shr);
var rhs = try (try self.binOp(shr_tmp, .{ .imm32 = 0xFF00FF }, ty, .@"and")).toLocal(self, ty);
defer rhs.free(self);
var tmp_or = try (try self.binOp(lhs, rhs, ty, .@"or")).toLocal(self, ty);
defer tmp_or.free(self);
const shl = try self.binOp(tmp_or, .{ .imm32 = 16 }, ty, .shl);
const shr = try self.binOp(tmp_or, .{ .imm32 = 16 }, ty, .shr);
const res = if (int_info.signedness == .signed) blk: {
break :blk try self.wrapOperand(shr, Type.u16);
} else shr;
return (try self.binOp(shl, res, ty, .@"or")).toLocal(self, ty);
},
else => return self.fail("TODO: @byteSwap for integers with bitsize {d}", .{int_info.bits}),
}
}
fn airDiv(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const bin_op = self.air.instructions.items(.data)[inst].bin_op;
const ty = self.air.typeOfIndex(inst);
const lhs = try self.resolveInst(bin_op.lhs);
const rhs = try self.resolveInst(bin_op.rhs);
if (ty.isSignedInt()) {
return self.divSigned(lhs, rhs, ty);
}
return (try self.binOp(lhs, rhs, ty, .div)).toLocal(self, ty);
}
fn airDivFloor(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const bin_op = self.air.instructions.items(.data)[inst].bin_op;
const ty = self.air.typeOfIndex(inst);
const lhs = try self.resolveInst(bin_op.lhs);
const rhs = try self.resolveInst(bin_op.rhs);
if (ty.isUnsignedInt()) {
return (try self.binOp(lhs, rhs, ty, .div)).toLocal(self, ty);
} else if (ty.isSignedInt()) {
const int_bits = ty.intInfo(self.target).bits;
const wasm_bits = toWasmBits(int_bits) orelse {
return self.fail("TODO: `@divFloor` for signed integers larger than '{d}' bits", .{int_bits});
};
const lhs_res = if (wasm_bits != int_bits) blk: {
break :blk try (try self.signAbsValue(lhs, ty)).toLocal(self, ty);
} else lhs;
const rhs_res = if (wasm_bits != int_bits) blk: {
break :blk try (try self.signAbsValue(rhs, ty)).toLocal(self, ty);
} else rhs;
const zero = switch (wasm_bits) {
32 => WValue{ .imm32 = 0 },
64 => WValue{ .imm64 = 0 },
else => unreachable,
};
const div_result = try self.allocLocal(ty);
// leave on stack
_ = try self.binOp(lhs_res, rhs_res, ty, .div);
try self.addLabel(.local_tee, div_result.local);
_ = try self.cmp(lhs_res, zero, ty, .lt);
_ = try self.cmp(rhs_res, zero, ty, .lt);
switch (wasm_bits) {
32 => {
try self.addTag(.i32_xor);
try self.addTag(.i32_sub);
},
64 => {
try self.addTag(.i64_xor);
try self.addTag(.i64_sub);
},
else => unreachable,
}
try self.emitWValue(div_result);
// leave value on the stack
_ = try self.binOp(lhs_res, rhs_res, ty, .rem);
try self.addTag(.select);
} else {
const float_bits = ty.floatBits(self.target);
if (float_bits > 64) {
return self.fail("TODO: `@divFloor` for floats with bitsize: {d}", .{float_bits});
}
const is_f16 = float_bits == 16;
const lhs_operand = if (is_f16) blk: {
break :blk try self.fpext(lhs, Type.f16, Type.f32);
} else lhs;
const rhs_operand = if (is_f16) blk: {
break :blk try self.fpext(rhs, Type.f16, Type.f32);
} else rhs;
try self.emitWValue(lhs_operand);
try self.emitWValue(rhs_operand);
switch (float_bits) {
16, 32 => {
try self.addTag(.f32_div);
try self.addTag(.f32_floor);
},
64 => {
try self.addTag(.f64_div);
try self.addTag(.f64_floor);
},
else => unreachable,
}
if (is_f16) {
_ = try self.fptrunc(.{ .stack = {} }, Type.f32, Type.f16);
}
}
const result = try self.allocLocal(ty);
try self.addLabel(.local_set, result.local);
return result;
}
fn divSigned(self: *Self, lhs: WValue, rhs: WValue, ty: Type) InnerError!WValue {
const int_bits = ty.intInfo(self.target).bits;
const wasm_bits = toWasmBits(int_bits) orelse {
return self.fail("TODO: Implement signed division for integers with bitsize '{d}'", .{int_bits});
};
if (wasm_bits == 128) {
return self.fail("TODO: Implement signed division for 128-bit integerrs", .{});
}
if (wasm_bits != int_bits) {
// Leave both values on the stack
_ = try self.signAbsValue(lhs, ty);
_ = try self.signAbsValue(rhs, ty);
} else {
try self.emitWValue(lhs);
try self.emitWValue(rhs);
}
try self.addTag(.i32_div_s);
const result = try self.allocLocal(ty);
try self.addLabel(.local_set, result.local);
return result;
}
/// Retrieves the absolute value of a signed integer
/// NOTE: Leaves the result value on the stack.
fn signAbsValue(self: *Self, operand: WValue, ty: Type) InnerError!WValue {
const int_bits = ty.intInfo(self.target).bits;
const wasm_bits = toWasmBits(int_bits) orelse {
return self.fail("TODO: signAbsValue for signed integers larger than '{d}' bits", .{int_bits});
};
const shift_val = switch (wasm_bits) {
32 => WValue{ .imm32 = wasm_bits - int_bits },
64 => WValue{ .imm64 = wasm_bits - int_bits },
else => return self.fail("TODO: signAbsValue for i128", .{}),
};
try self.emitWValue(operand);
switch (wasm_bits) {
32 => {
try self.emitWValue(shift_val);
try self.addTag(.i32_shl);
try self.emitWValue(shift_val);
try self.addTag(.i32_shr_s);
},
64 => {
try self.emitWValue(shift_val);
try self.addTag(.i64_shl);
try self.emitWValue(shift_val);
try self.addTag(.i64_shr_s);
},
else => unreachable,
}
return WValue{ .stack = {} };
}
fn airCeilFloorTrunc(self: *Self, inst: Air.Inst.Index, op: Op) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const un_op = self.air.instructions.items(.data)[inst].un_op;
const ty = self.air.typeOfIndex(inst);
const float_bits = ty.floatBits(self.target);
const is_f16 = float_bits == 16;
if (ty.zigTypeTag() == .Vector) {
return self.fail("TODO: Implement `@ceil` for vectors", .{});
}
if (float_bits > 64) {
return self.fail("TODO: implement `@ceil`, `@trunc`, `@floor` for floats larger than 64bits", .{});
}
const operand = try self.resolveInst(un_op);
const op_to_lower = if (is_f16) blk: {
break :blk try self.fpext(operand, Type.f16, Type.f32);
} else operand;
try self.emitWValue(op_to_lower);
const opcode = buildOpcode(.{ .op = op, .valtype1 = typeToValtype(ty, self.target) });
try self.addTag(Mir.Inst.Tag.fromOpcode(opcode));
if (is_f16) {
_ = try self.fptrunc(.{ .stack = {} }, Type.f32, Type.f16);
}
const result = try self.allocLocal(ty);
try self.addLabel(.local_set, result.local);
return result;
}
fn airSatBinOp(self: *Self, inst: Air.Inst.Index, op: Op) InnerError!WValue {
assert(op == .add or op == .sub);
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const bin_op = self.air.instructions.items(.data)[inst].bin_op;
const ty = self.air.typeOfIndex(inst);
const lhs = try self.resolveInst(bin_op.lhs);
const rhs = try self.resolveInst(bin_op.rhs);
const int_info = ty.intInfo(self.target);
const is_signed = int_info.signedness == .signed;
if (int_info.bits > 64) {
return self.fail("TODO: saturating arithmetic for integers with bitsize '{d}'", .{int_info.bits});
}
if (is_signed) {
return signedSat(self, lhs, rhs, ty, op);
}
const wasm_bits = toWasmBits(int_info.bits).?;
var bin_result = try (try self.binOp(lhs, rhs, ty, op)).toLocal(self, ty);
defer bin_result.free(self);
if (wasm_bits != int_info.bits and op == .add) {
const val: u64 = @intCast(u64, (@as(u65, 1) << @intCast(u7, int_info.bits)) - 1);
const imm_val = switch (wasm_bits) {
32 => WValue{ .imm32 = @intCast(u32, val) },
64 => WValue{ .imm64 = val },
else => unreachable,
};
try self.emitWValue(bin_result);
try self.emitWValue(imm_val);
_ = try self.cmp(bin_result, imm_val, ty, .lt);
} else {
switch (wasm_bits) {
32 => try self.addImm32(if (op == .add) @as(i32, -1) else 0),
64 => try self.addImm64(if (op == .add) @bitCast(u64, @as(i64, -1)) else 0),
else => unreachable,
}
try self.emitWValue(bin_result);
_ = try self.cmp(bin_result, lhs, ty, if (op == .add) .lt else .gt);
}
try self.addTag(.select);
const result = try self.allocLocal(ty);
try self.addLabel(.local_set, result.local);
return result;
}
fn signedSat(self: *Self, lhs_operand: WValue, rhs_operand: WValue, ty: Type, op: Op) InnerError!WValue {
const int_info = ty.intInfo(self.target);
const wasm_bits = toWasmBits(int_info.bits).?;
const is_wasm_bits = wasm_bits == int_info.bits;
var lhs = if (!is_wasm_bits) lhs: {
break :lhs try (try self.signAbsValue(lhs_operand, ty)).toLocal(self, ty);
} else lhs_operand;
var rhs = if (!is_wasm_bits) rhs: {
break :rhs try (try self.signAbsValue(rhs_operand, ty)).toLocal(self, ty);
} else rhs_operand;
const max_val: u64 = @intCast(u64, (@as(u65, 1) << @intCast(u7, int_info.bits - 1)) - 1);
const min_val: i64 = (-@intCast(i64, @intCast(u63, max_val))) - 1;
const max_wvalue = switch (wasm_bits) {
32 => WValue{ .imm32 = @truncate(u32, max_val) },
64 => WValue{ .imm64 = max_val },
else => unreachable,
};
const min_wvalue = switch (wasm_bits) {
32 => WValue{ .imm32 = @bitCast(u32, @truncate(i32, min_val)) },
64 => WValue{ .imm64 = @bitCast(u64, min_val) },
else => unreachable,
};
var bin_result = try (try self.binOp(lhs, rhs, ty, op)).toLocal(self, ty);
if (!is_wasm_bits) {
defer bin_result.free(self); // not returned in this branch
defer lhs.free(self); // uses temporary local for absvalue
defer rhs.free(self); // uses temporary local for absvalue
try self.emitWValue(bin_result);
try self.emitWValue(max_wvalue);
_ = try self.cmp(bin_result, max_wvalue, ty, .lt);
try self.addTag(.select);
try self.addLabel(.local_set, bin_result.local); // re-use local
try self.emitWValue(bin_result);
try self.emitWValue(min_wvalue);
_ = try self.cmp(bin_result, min_wvalue, ty, .gt);
try self.addTag(.select);
try self.addLabel(.local_set, bin_result.local); // re-use local
return (try self.wrapOperand(bin_result, ty)).toLocal(self, ty);
} else {
const zero = switch (wasm_bits) {
32 => WValue{ .imm32 = 0 },
64 => WValue{ .imm64 = 0 },
else => unreachable,
};
try self.emitWValue(max_wvalue);
try self.emitWValue(min_wvalue);
_ = try self.cmp(bin_result, zero, ty, .lt);
try self.addTag(.select);
try self.emitWValue(bin_result);
// leave on stack
const cmp_zero_result = try self.cmp(rhs, zero, ty, if (op == .add) .lt else .gt);
const cmp_bin_result = try self.cmp(bin_result, lhs, ty, .lt);
_ = try self.binOp(cmp_zero_result, cmp_bin_result, Type.u32, .xor); // comparisons always return i32, so provide u32 as type to xor.
try self.addTag(.select);
try self.addLabel(.local_set, bin_result.local); // re-use local
return bin_result;
}
}
fn airShlSat(self: *Self, inst: Air.Inst.Index) InnerError!WValue {
if (self.liveness.isUnused(inst)) return WValue{ .none = {} };
const bin_op = self.air.instructions.items(.data)[inst].bin_op;
const ty = self.air.typeOfIndex(inst);
const int_info = ty.intInfo(self.target);
const is_signed = int_info.signedness == .signed;
if (int_info.bits > 64) {
return self.fail("TODO: Saturating shifting left for integers with bitsize '{d}'", .{int_info.bits});
}
const lhs = try self.resolveInst(bin_op.lhs);
const rhs = try self.resolveInst(bin_op.rhs);
const wasm_bits = toWasmBits(int_info.bits).?;
const result = try self.allocLocal(ty);
if (wasm_bits == int_info.bits) {
var shl = try (try self.binOp(lhs, rhs, ty, .shl)).toLocal(self, ty);
defer shl.free(self);
var shr = try (try self.binOp(shl, rhs, ty, .shr)).toLocal(self, ty);
defer shr.free(self);
switch (wasm_bits) {
32 => blk: {
if (!is_signed) {
try self.addImm32(-1);
break :blk;
}
try self.addImm32(std.math.minInt(i32));
try self.addImm32(std.math.maxInt(i32));
_ = try self.cmp(lhs, .{ .imm32 = 0 }, ty, .lt);
try self.addTag(.select);
},
64 => blk: {
if (!is_signed) {
try self.addImm64(@bitCast(u64, @as(i64, -1)));
break :blk;
}
try self.addImm64(@bitCast(u64, @as(i64, std.math.minInt(i64))));
try self.addImm64(@bitCast(u64, @as(i64, std.math.maxInt(i64))));
_ = try self.cmp(lhs, .{ .imm64 = 0 }, ty, .lt);
try self.addTag(.select);
},
else => unreachable,
}
try self.emitWValue(shl);
_ = try self.cmp(lhs, shr, ty, .neq);
try self.addTag(.select);
try self.addLabel(.local_set, result.local);
return result;
} else {
const shift_size = wasm_bits - int_info.bits;
const shift_value = switch (wasm_bits) {
32 => WValue{ .imm32 = shift_size },
64 => WValue{ .imm64 = shift_size },
else => unreachable,
};
var shl_res = try (try self.binOp(lhs, shift_value, ty, .shl)).toLocal(self, ty);
defer shl_res.free(self);
var shl = try (try self.binOp(shl_res, rhs, ty, .shl)).toLocal(self, ty);
defer shl.free(self);
var shr = try (try self.binOp(shl, rhs, ty, .shr)).toLocal(self, ty);
defer shr.free(self);
switch (wasm_bits) {
32 => blk: {
if (!is_signed) {
try self.addImm32(-1);
break :blk;
}
try self.addImm32(std.math.minInt(i32));
try self.addImm32(std.math.maxInt(i32));
_ = try self.cmp(shl_res, .{ .imm32 = 0 }, ty, .lt);
try self.addTag(.select);
},
64 => blk: {
if (!is_signed) {
try self.addImm64(@bitCast(u64, @as(i64, -1)));
break :blk;
}
try self.addImm64(@bitCast(u64, @as(i64, std.math.minInt(i64))));
try self.addImm64(@bitCast(u64, @as(i64, std.math.maxInt(i64))));
_ = try self.cmp(shl_res, .{ .imm64 = 0 }, ty, .lt);
try self.addTag(.select);
},
else => unreachable,
}
try self.emitWValue(shl);
_ = try self.cmp(shl_res, shr, ty, .neq);
try self.addTag(.select);
try self.addLabel(.local_set, result.local);
var shift_result = try self.binOp(result, shift_value, ty, .shr);
if (is_signed) {
shift_result = try self.wrapOperand(shift_result, ty);
}
return shift_result.toLocal(self, ty);
}
}
/// Calls a compiler-rt intrinsic by creating an undefined symbol,
/// then lowering the arguments and calling the symbol as a function call.
/// This function call assumes the C-ABI.
/// Asserts arguments are not stack values when the return value is
/// passed as the first parameter.
/// May leave the return value on the stack.
fn callIntrinsic(
self: *Self,
name: []const u8,
param_types: []const Type,
return_type: Type,
args: []const WValue,
) InnerError!WValue {
assert(param_types.len == args.len);
const symbol_index = self.bin_file.base.getGlobalSymbol(name) catch |err| {
return self.fail("Could not find or create global symbol '{s}'", .{@errorName(err)});
};
// Always pass over C-ABI
var func_type = try genFunctype(self.gpa, .C, param_types, return_type, self.target);
defer func_type.deinit(self.gpa);
const func_type_index = try self.bin_file.putOrGetFuncType(func_type);
try self.bin_file.addOrUpdateImport(name, symbol_index, null, func_type_index);
const want_sret_param = firstParamSRet(.C, return_type, self.target);
// if we want return as first param, we allocate a pointer to stack,
// and emit it as our first argument
const sret = if (want_sret_param) blk: {
const sret_local = try self.allocStack(return_type);
try self.lowerToStack(sret_local);
break :blk sret_local;
} else WValue{ .none = {} };
// Lower all arguments to the stack before we call our function
for (args) |arg, arg_i| {
assert(!(want_sret_param and arg == .stack));
assert(param_types[arg_i].hasRuntimeBitsIgnoreComptime());
try self.lowerArg(.C, param_types[arg_i], arg);
}
// Actually call our intrinsic
try self.addLabel(.call, symbol_index);
if (!return_type.hasRuntimeBitsIgnoreComptime()) {
return WValue.none;
} else if (return_type.isNoReturn()) {
try self.addTag(.@"unreachable");
return WValue.none;
} else if (want_sret_param) {
return sret;
} else {
return WValue{ .stack = {} };
}
}
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