zig/lib/std/debug/Dwarf/expression.zig
2025-07-01 16:35:29 -07:00

1674 lines
76 KiB
Zig

const builtin = @import("builtin");
const native_arch = builtin.cpu.arch;
const native_endian = native_arch.endian();
const std = @import("std");
const leb = std.leb;
const OP = std.dwarf.OP;
const abi = std.debug.Dwarf.abi;
const mem = std.mem;
const assert = std.debug.assert;
const Allocator = std.mem.Allocator;
const Writer = std.io.Writer;
/// Expressions can be evaluated in different contexts, each requiring its own set of inputs.
/// Callers should specify all the fields relevant to their context. If a field is required
/// by the expression and it isn't in the context, error.IncompleteExpressionContext is returned.
pub const Context = struct {
/// The dwarf format of the section this expression is in
format: std.dwarf.Format = .@"32",
/// If specified, any addresses will pass through before being accessed
memory_accessor: ?*std.debug.MemoryAccessor = null,
/// The compilation unit this expression relates to, if any
compile_unit: ?*const std.debug.Dwarf.CompileUnit = null,
/// When evaluating a user-presented expression, this is the address of the object being evaluated
object_address: ?*const anyopaque = null,
/// .debug_addr section
debug_addr: ?[]const u8 = null,
/// Thread context
thread_context: ?*std.debug.ThreadContext = null,
reg_context: ?abi.RegisterContext = null,
/// Call frame address, if in a CFI context
cfa: ?usize = null,
/// This expression is a sub-expression from an OP.entry_value instruction
entry_value_context: bool = false,
};
pub const Options = struct {
/// The address size of the target architecture
addr_size: u8 = @sizeOf(usize),
/// Endianness of the target architecture
endian: std.builtin.Endian = native_endian,
/// Restrict the stack machine to a subset of opcodes used in call frame instructions
call_frame_context: bool = false,
};
pub const RunError = error{
UnimplementedExpressionCall,
UnimplementedOpcode,
UnimplementedUserOpcode,
UnimplementedTypedComparison,
UnimplementedTypeConversion,
UnknownExpressionOpcode,
IncompleteExpressionContext,
InvalidCFAOpcode,
InvalidExpression,
InvalidFrameBase,
InvalidIntegralTypeSize,
InvalidRegister,
InvalidSubExpression,
InvalidTypeLength,
TruncatedIntegralType,
OutOfMemory,
EndOfStream,
Overflow,
DivisionByZero,
} || abi.RegBytesError;
/// A stack machine that can decode and run DWARF expressions.
/// Expressions can be decoded for non-native address size and endianness,
/// but can only be executed if the current target matches the configuration.
pub fn StackMachine(comptime options: Options) type {
const Address = switch (options.addr_size) {
2 => u16,
4 => u32,
8 => u64,
else => @compileError("Unsupported address size of " ++ options.addr_size),
};
const SignedAddress = switch (options.addr_size) {
2 => i16,
4 => i32,
8 => i64,
else => @compileError("Unsupported address size of " ++ options.addr_size),
};
return struct {
stack: std.ArrayListUnmanaged(Value) = .empty,
const Self = @This();
const Value = union(enum) {
generic: Address,
// Typed value with a maximum size of a register
regval_type: struct {
// Offset of DW_TAG_base_type DIE
type_offset: Address,
type_size: u8,
value: Address,
},
// Typed value specified directly in the instruction stream
const_type: struct {
// Offset of DW_TAG_base_type DIE
type_offset: Address,
// Backed by the instruction stream
value_bytes: []const u8,
},
fn asIntegral(self: Value) !Address {
return switch (self) {
.generic => |v| v,
// TODO: For these two prongs, look up the type and assert it's integral?
.regval_type => |regval_type| regval_type.value,
.const_type => |const_type| {
const value: u64 = switch (const_type.value_bytes.len) {
1 => mem.readInt(u8, const_type.value_bytes[0..1], native_endian),
2 => mem.readInt(u16, const_type.value_bytes[0..2], native_endian),
4 => mem.readInt(u32, const_type.value_bytes[0..4], native_endian),
8 => mem.readInt(u64, const_type.value_bytes[0..8], native_endian),
else => return error.InvalidIntegralTypeSize,
};
return std.math.cast(Address, value) orelse error.TruncatedIntegralType;
},
};
}
fn fromInt(int: anytype) Value {
const info = @typeInfo(@TypeOf(int)).int;
if (@sizeOf(@TypeOf(int)) > options.addr_size) {
return .{ .generic = switch (info.signedness) {
.signed => @bitCast(@as(SignedAddress, @truncate(int))),
.unsigned => @truncate(int),
} };
} else {
return .{ .generic = switch (info.signedness) {
.signed => @bitCast(@as(SignedAddress, @intCast(int))),
.unsigned => @intCast(int),
} };
}
}
};
pub fn reset(self: *Self) void {
self.stack.clearRetainingCapacity();
}
pub fn deinit(self: *Self, allocator: Allocator) void {
self.stack.deinit(allocator);
}
pub fn run(
self: *Self,
expression: []const u8,
gpa: Allocator,
context: Context,
initial_value: ?usize,
) RunError!?Value {
if (@sizeOf(usize) != @sizeOf(Address) or options.endian != native_endian) {
// This restriction can be removed when the `@ptrFromInt` calls are removed.
@compileError("Execution of non-native address sizes / endianness is not supported");
}
const stack = &self.stack;
if (initial_value) |i| try stack.append(gpa, .{ .generic = i });
var i: usize = 0;
// TODO: https://github.com/ziglang/zig/issues/15556
op: switch (nextOpcode(expression, &i)) {
// 2.5.1.1: Literal Encodings
@intFromEnum(OP.lit0)...@intFromEnum(OP.lit31) => |n| {
try stack.append(gpa, .{ .generic = n - @intFromEnum(OP.lit0) });
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.addr) => {
try stack.append(gpa, .fromInt(try nextInt(expression, &i, Address)));
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.const1u) => {
try stack.append(gpa, .fromInt(try nextInt(expression, &i, u8)));
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.const2u) => {
try stack.append(gpa, .fromInt(try nextInt(expression, &i, u16)));
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.const4u) => {
try stack.append(gpa, .fromInt(try nextInt(expression, &i, u32)));
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.const8u) => {
try stack.append(gpa, .fromInt(try nextInt(expression, &i, u64)));
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.const1s) => {
try stack.append(gpa, .fromInt(try nextInt(expression, &i, i8)));
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.const2s) => {
try stack.append(gpa, .fromInt(try nextInt(expression, &i, i16)));
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.const4s) => {
try stack.append(gpa, .fromInt(try nextInt(expression, &i, i32)));
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.const8s) => {
try stack.append(gpa, .fromInt(try nextInt(expression, &i, i64)));
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.constu) => {
try stack.append(gpa, .fromInt(try nextLeb128(expression, &i, u64)));
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.consts) => {
try stack.append(gpa, .fromInt(try nextLeb128(expression, &i, i64)));
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.const_type) => {
if (options.call_frame_context) return error.InvalidCFAOpcode;
try stack.append(gpa, .{ .const_type = .{
.type_offset = try nextLeb128(expression, &i, Address),
.value_bytes = try nextSlice(expression, &i, try nextInt(expression, &i, u8)),
} });
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.addrx),
@intFromEnum(OP.constx),
=> {
if (options.call_frame_context) return error.InvalidCFAOpcode;
const compile_unit = context.compile_unit orelse return error.IncompleteExpressionContext;
const debug_addr = context.debug_addr orelse return error.IncompleteExpressionContext;
const debug_addr_index = try nextLeb128(expression, &i, u64);
const offset = compile_unit.addr_base + debug_addr_index;
if (offset >= debug_addr.len) return error.InvalidExpression;
const value = mem.readInt(Address, debug_addr[offset..][0..@sizeOf(Address)], options.endian);
try stack.append(gpa, .fromInt(value));
continue :op nextOpcode(expression, &i);
},
// 2.5.1.2: Register Values
@intFromEnum(OP.fbreg) => {
const compile_unit = context.compile_unit orelse return error.IncompleteExpressionContext;
const frame_base = compile_unit.frame_base orelse return error.IncompleteExpressionContext;
const offset = try nextLeb128(expression, &i, i64);
_ = offset;
switch (frame_base.*) {
.exprloc => {
// TODO: Run this expression in a nested stack machine
return error.UnimplementedOpcode;
},
.loclistx => {
// TODO: Read value from .debug_loclists
return error.UnimplementedOpcode;
},
.sec_offset => {
// TODO: Read value from .debug_loclists
return error.UnimplementedOpcode;
},
else => return error.InvalidFrameBase,
}
},
@intFromEnum(OP.breg0)...@intFromEnum(OP.breg31) => |n| {
const thread_context = context.thread_context orelse return error.IncompleteExpressionContext;
const base_register = n - @intFromEnum(OP.breg0);
const offset = try nextLeb128(expression, &i, i64);
const reg_bytes = try abi.regBytes(thread_context, base_register, context.reg_context);
const start_addr = mem.readInt(Address, reg_bytes[0..@sizeOf(Address)], options.endian);
try stack.append(gpa, .{
.generic = std.math.addAny(Address, start_addr, offset) orelse
return error.InvalidExpression,
});
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.bregx) => {
const thread_context = context.thread_context orelse return error.IncompleteExpressionContext;
const base_register = try nextLeb128(expression, &i, u8);
const offset = try nextLeb128(expression, &i, i64);
const reg_bytes = try abi.regBytes(thread_context, base_register, context.reg_context);
const start_addr = mem.readInt(Address, reg_bytes[0..@sizeOf(Address)], options.endian);
try stack.append(gpa, .{
.generic = std.math.addAny(Address, start_addr, offset) orelse
return error.InvalidExpression,
});
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.regval_type) => {
if (options.call_frame_context) return error.InvalidCFAOpcode;
const thread_context = context.thread_context orelse return error.IncompleteExpressionContext;
const register = try nextLeb128(expression, &i, u8);
const type_offset = try nextLeb128(expression, &i, Address);
const reg_bytes = try abi.regBytes(thread_context, register, context.reg_context);
const value = mem.readInt(Address, reg_bytes[0..@sizeOf(Address)], options.endian);
try stack.append(gpa, .{
.regval_type = .{
.type_offset = type_offset,
.type_size = @sizeOf(Address),
.value = value,
},
});
continue :op nextOpcode(expression, &i);
},
// 2.5.1.3: Stack Operations
@intFromEnum(OP.dup) => {
if (stack.items.len == 0) return error.InvalidExpression;
try stack.append(gpa, stack.items[stack.items.len - 1]);
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.drop) => {
_ = stack.pop();
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.pick) => {
const stack_index = try nextInt(expression, &i, u8);
if (stack_index >= stack.items.len) return error.InvalidExpression;
try stack.append(gpa, stack.items[stack.items.len - 1 - stack_index]);
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.over) => {
if (stack.items.len < 2) return error.InvalidExpression;
try stack.append(gpa, stack.items[stack.items.len - 2]);
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.swap) => {
if (stack.items.len < 2) return error.InvalidExpression;
mem.swap(Value, &stack.items[stack.items.len - 1], &stack.items[stack.items.len - 2]);
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.rot) => {
if (stack.items.len < 3) return error.InvalidExpression;
const first = stack.items[stack.items.len - 1];
stack.items[stack.items.len - 1] = stack.items[stack.items.len - 2];
stack.items[stack.items.len - 2] = stack.items[stack.items.len - 3];
stack.items[stack.items.len - 3] = first;
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.deref_type) => {
if (options.call_frame_context) return error.InvalidCFAOpcode;
if (stack.items.len == 0) return error.InvalidExpression;
const size = try nextInt(expression, &i, u8);
const type_offset = try nextLeb128(expression, &i, Address);
const addr = try stack.items[stack.items.len - 1].asIntegral();
const loaded = try accessAddress(size, addr, context.memory_accessor);
stack.items[stack.items.len - 1] = .{
.regval_type = .{
.type_offset = type_offset,
.type_size = size,
.value = loaded,
},
};
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.deref_size) => {
if (stack.items.len == 0) return error.InvalidExpression;
const addr = try stack.items[stack.items.len - 1].asIntegral();
const type_size = try nextInt(expression, &i, u8);
const loaded = try accessAddress(type_size, addr, context.memory_accessor);
stack.items[stack.items.len - 1] = .{ .generic = loaded };
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.xderef_size) => {
if (stack.items.len < 2) return error.InvalidExpression;
const type_size = try nextInt(expression, &i, u8);
const addr = try stack.pop().?.asIntegral();
const addr_space_identifier = try stack.items[stack.items.len - 1].asIntegral();
// Usage of addr_space_identifier in the address calculation is implementation defined.
// This code will need to be updated to handle any architectures that utilize this.
_ = addr_space_identifier;
const loaded = try accessAddress(type_size, addr, context.memory_accessor);
stack.items[stack.items.len - 1] = .{ .generic = loaded };
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.deref) => {
if (stack.items.len == 0) return error.InvalidExpression;
const addr = try stack.items[stack.items.len - 1].asIntegral();
const loaded = try accessAddress(@sizeOf(Address), addr, context.memory_accessor);
stack.items[stack.items.len - 1] = .{ .generic = loaded };
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.xderef) => {
if (stack.items.len < 2) return error.InvalidExpression;
const addr = try stack.pop().?.asIntegral();
const addr_space_identifier = try stack.items[stack.items.len - 1].asIntegral();
// Usage of addr_space_identifier in the address calculation is implementation defined.
// This code will need to be updated to handle any architectures that utilize this.
_ = addr_space_identifier;
const loaded = try accessAddress(@sizeOf(Address), addr, context.memory_accessor);
stack.items[stack.items.len - 1] = .{ .generic = loaded };
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.xderef_type),
=> {
if (stack.items.len < 2) return error.InvalidExpression;
const addr = try stack.pop().?.asIntegral();
const addr_space_identifier = try stack.items[stack.items.len - 1].asIntegral();
// Usage of addr_space_identifier in the address calculation is implementation defined.
// This code will need to be updated to handle any architectures that utilize this.
_ = addr_space_identifier;
const size = try nextInt(expression, &i, u8);
const type_offset = try nextLeb128(expression, &i, Address);
const loaded = try accessAddress(size, addr, context.memory_accessor);
stack.items[stack.items.len - 1] = .{
.regval_type = .{
.type_offset = type_offset,
.type_size = size,
.value = loaded,
},
};
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.push_object_address) => {
if (options.call_frame_context) return error.InvalidCFAOpcode;
// In sub-expressions, `push_object_address` is not meaningful (as per the
// spec), so treat it like a nop
if (!context.entry_value_context) {
if (context.object_address == null) return error.IncompleteExpressionContext;
try stack.append(gpa, .{ .generic = @intFromPtr(context.object_address.?) });
}
},
@intFromEnum(OP.form_tls_address) => {
return error.UnimplementedOpcode;
},
@intFromEnum(OP.call_frame_cfa) => {
if (options.call_frame_context) return error.InvalidCFAOpcode;
if (context.cfa) |cfa| {
try stack.append(gpa, .{ .generic = cfa });
} else return error.IncompleteExpressionContext;
continue :op nextOpcode(expression, &i);
},
// 2.5.1.4: Arithmetic and Logical Operations
@intFromEnum(OP.abs) => {
if (stack.items.len == 0) return error.InvalidExpression;
const value: isize = @bitCast(try stack.items[stack.items.len - 1].asIntegral());
stack.items[stack.items.len - 1] = .{
.generic = @abs(value),
};
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.@"and") => {
if (stack.items.len < 2) return error.InvalidExpression;
const a = try stack.pop().?.asIntegral();
stack.items[stack.items.len - 1] = .{
.generic = a & try stack.items[stack.items.len - 1].asIntegral(),
};
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.div) => {
if (stack.items.len < 2) return error.InvalidExpression;
const a: isize = @bitCast(try stack.pop().?.asIntegral());
const b: isize = @bitCast(try stack.items[stack.items.len - 1].asIntegral());
stack.items[stack.items.len - 1] = .{
.generic = @bitCast(try std.math.divTrunc(isize, b, a)),
};
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.minus) => {
if (stack.items.len < 2) return error.InvalidExpression;
const b = try stack.pop().?.asIntegral();
stack.items[stack.items.len - 1] = .{
.generic = try std.math.sub(Address, try stack.items[stack.items.len - 1].asIntegral(), b),
};
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.mod) => {
if (stack.items.len < 2) return error.InvalidExpression;
const a: isize = @bitCast(try stack.pop().?.asIntegral());
const b: isize = @bitCast(try stack.items[stack.items.len - 1].asIntegral());
stack.items[stack.items.len - 1] = .{
.generic = @bitCast(@mod(b, a)),
};
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.mul) => {
if (stack.items.len < 2) return error.InvalidExpression;
const a: isize = @bitCast(try stack.pop().?.asIntegral());
const b: isize = @bitCast(try stack.items[stack.items.len - 1].asIntegral());
stack.items[stack.items.len - 1] = .{
.generic = @bitCast(@mulWithOverflow(a, b)[0]),
};
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.neg) => {
if (stack.items.len == 0) return error.InvalidExpression;
stack.items[stack.items.len - 1] = .{
.generic = @bitCast(
try std.math.negate(
@as(isize, @bitCast(try stack.items[stack.items.len - 1].asIntegral())),
),
),
};
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.not) => {
if (stack.items.len == 0) return error.InvalidExpression;
stack.items[stack.items.len - 1] = .{
.generic = ~try stack.items[stack.items.len - 1].asIntegral(),
};
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.@"or") => {
if (stack.items.len < 2) return error.InvalidExpression;
const a = try stack.pop().?.asIntegral();
stack.items[stack.items.len - 1] = .{
.generic = a | try stack.items[stack.items.len - 1].asIntegral(),
};
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.plus) => {
if (stack.items.len < 2) return error.InvalidExpression;
const b = try stack.pop().?.asIntegral();
stack.items[stack.items.len - 1] = .{
.generic = try std.math.add(Address, try stack.items[stack.items.len - 1].asIntegral(), b),
};
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.plus_uconst) => {
if (stack.items.len == 0) return error.InvalidExpression;
stack.items[stack.items.len - 1] = .{ .generic = std.math.addAny(
Address,
try nextLeb128(expression, &i, u64),
try stack.items[stack.items.len - 1].asIntegral(),
) orelse return error.Overflow };
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.shl) => {
if (stack.items.len < 2) return error.InvalidExpression;
const a = try stack.pop().?.asIntegral();
const b = try stack.items[stack.items.len - 1].asIntegral();
stack.items[stack.items.len - 1] = .{
.generic = std.math.shl(usize, b, a),
};
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.shr) => {
if (stack.items.len < 2) return error.InvalidExpression;
const a = try stack.pop().?.asIntegral();
const b = try stack.items[stack.items.len - 1].asIntegral();
stack.items[stack.items.len - 1] = .{
.generic = std.math.shr(usize, b, a),
};
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.shra) => {
if (stack.items.len < 2) return error.InvalidExpression;
const a = try stack.pop().?.asIntegral();
const b: isize = @bitCast(try stack.items[stack.items.len - 1].asIntegral());
stack.items[stack.items.len - 1] = .{
.generic = @bitCast(std.math.shr(isize, b, a)),
};
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.xor) => {
if (stack.items.len < 2) return error.InvalidExpression;
const a = try stack.pop().?.asIntegral();
stack.items[stack.items.len - 1] = .{
.generic = a ^ try stack.items[stack.items.len - 1].asIntegral(),
};
continue :op nextOpcode(expression, &i);
},
// 2.5.1.5: Control Flow Operations
@intFromEnum(OP.le) => {
try cmpOp(stack, .lte);
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.ge) => {
try cmpOp(stack, .gte);
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.eq) => {
try cmpOp(stack, .eq);
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.lt) => {
try cmpOp(stack, .lt);
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.gt) => {
try cmpOp(stack, .gt);
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.ne) => {
try cmpOp(stack, .neq);
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.skip) => {
const branch_offset = try nextInt(expression, &i, i16);
i = std.math.addAny(usize, i, branch_offset) orelse return error.InvalidExpression;
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.bra) => {
const branch_offset = try nextInt(expression, &i, i16);
const condition = try (stack.pop() orelse return error.InvalidExpression).asIntegral();
if (condition != 0) {
i = std.math.addAny(usize, i, branch_offset) orelse return error.InvalidExpression;
}
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.call2) => {
if (options.call_frame_context) return error.InvalidCFAOpcode;
const debug_info_offset = nextInt(expression, &i, u16);
_ = debug_info_offset;
// TODO: Load a DIE entry at debug_info_offset in a .debug_info section (the spec says that it
// can be in a separate exe / shared object from the one containing this expression).
// Transfer control to the DW_AT_location attribute, with the current stack as input.
return error.UnimplementedExpressionCall;
},
@intFromEnum(OP.call4) => {
if (options.call_frame_context) return error.InvalidCFAOpcode;
const debug_info_offset = nextInt(expression, &i, u32);
_ = debug_info_offset;
// TODO: Load a DIE entry at debug_info_offset in a .debug_info section (the spec says that it
// can be in a separate exe / shared object from the one containing this expression).
// Transfer control to the DW_AT_location attribute, with the current stack as input.
return error.UnimplementedExpressionCall;
},
@intFromEnum(OP.call_ref) => {
if (options.call_frame_context) return error.InvalidCFAOpcode;
const debug_info_offset: u64 = switch (context.format) {
.@"32" => nextInt(expression, &i, u32),
.@"64" => nextInt(expression, &i, u64),
};
_ = debug_info_offset;
// TODO: Load a DIE entry at debug_info_offset in a .debug_info section (the spec says that it
// can be in a separate exe / shared object from the one containing this expression).
// Transfer control to the DW_AT_location attribute, with the current stack as input.
return error.UnimplementedExpressionCall;
},
// 2.5.1.6: Type Conversions
@intFromEnum(OP.convert) => {
if (options.call_frame_context) return error.InvalidCFAOpcode;
if (stack.items.len == 0) return error.InvalidExpression;
const type_offset = try nextLeb128(expression, &i, u64);
// TODO: Load the DW_TAG_base_type entries in context.compile_unit and verify both types are the same size
const value = stack.items[stack.items.len - 1];
if (type_offset == 0) {
stack.items[stack.items.len - 1] = .{ .generic = try value.asIntegral() };
} else {
// TODO: Load the DW_TAG_base_type entry in context.compile_unit, find a conversion operator
// from the old type to the new type, run it.
return error.UnimplementedTypeConversion;
}
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.reinterpret) => {
if (options.call_frame_context) return error.InvalidCFAOpcode;
if (stack.items.len == 0) return error.InvalidExpression;
const type_offset = try nextLeb128(expression, &i, u64);
// TODO: Load the DW_TAG_base_type entries in context.compile_unit and verify both types are the same size
const value = stack.items[stack.items.len - 1];
if (type_offset == 0) {
stack.items[stack.items.len - 1] = .{ .generic = try value.asIntegral() };
} else {
stack.items[stack.items.len - 1] = switch (value) {
.generic => |v| .{
.regval_type = .{
.type_offset = type_offset,
.type_size = @sizeOf(Address),
.value = v,
},
},
.regval_type => |r| .{
.regval_type = .{
.type_offset = type_offset,
.type_size = r.type_size,
.value = r.value,
},
},
.const_type => |c| .{
.const_type = .{
.type_offset = type_offset,
.value_bytes = c.value_bytes,
},
},
};
}
continue :op nextOpcode(expression, &i);
},
// 2.5.1.7: Special Operations
@intFromEnum(OP.nop) => continue :op nextOpcode(expression, &i),
@intFromEnum(OP.entry_value) => {
const block_len = try nextLeb128(expression, &i, usize);
if (block_len == 0) return error.InvalidSubExpression;
const block = try nextSlice(expression, &i, block_len);
// TODO: The spec states that this sub-expression needs to observe the state (ie. registers)
// as it was upon entering the current subprogram. If this isn't being called at the
// end of a frame unwind operation, an additional ThreadContext with this state will be needed.
switch (block[0]) {
@intFromEnum(OP.reg0)...@intFromEnum(OP.reg31) => |n| {
const thread_context = context.thread_context orelse
return error.IncompleteExpressionContext;
const register = n - @intFromEnum(OP.reg0);
const reg_bytes = try abi.regBytes(thread_context, register, context.reg_context);
const value = mem.readInt(usize, reg_bytes[0..@sizeOf(usize)], options.endian);
try stack.append(gpa, .{ .generic = value });
continue :op nextOpcode(expression, &i);
},
@intFromEnum(OP.regx) => {
const thread_context = context.thread_context orelse
return error.IncompleteExpressionContext;
const register = try nextLeb128(expression, &i, u8);
const reg_bytes = try abi.regBytes(thread_context, register, context.reg_context);
const value = mem.readInt(usize, reg_bytes[0..@sizeOf(usize)], options.endian);
try stack.append(gpa, .{ .generic = value });
continue :op nextOpcode(expression, &i);
},
else => {
var stack_machine: Self = .{};
defer stack_machine.deinit(gpa);
var sub_context = context;
sub_context.entry_value_context = true;
const result = try stack_machine.run(block, gpa, sub_context, null);
try stack.append(gpa, result orelse return error.InvalidSubExpression);
continue :op nextOpcode(expression, &i);
},
}
},
@intFromEnum(OP.lo_user)...@intFromEnum(OP.hi_user) - 1 => return error.UnimplementedUserOpcode,
// Repurposed for exiting the loop.
@intFromEnum(OP.hi_user) => {
if (stack.items.len == 0) return null;
return stack.items[stack.items.len - 1];
},
else => {
//std.debug.print("Unknown DWARF expression opcode: {x}\n", .{opcode});
return error.UnknownExpressionOpcode;
},
}
comptime unreachable;
}
fn nextOpcode(expression: []const u8, i: *usize) u8 {
const index = i.*;
if (expression.len - index == 0) return @intFromEnum(OP.hi_user); // repurposed to indicate end
i.* = index + 1;
return expression[index];
}
fn nextInt(expression: []const u8, i: *usize, comptime I: type) !I {
const n = @divExact(@bitSizeOf(I), 8);
const slice = try nextSlice(expression, i, n);
return mem.readInt(I, slice[0..n], options.endian);
}
fn nextSlice(expression: []const u8, i: *usize, len: usize) ![]const u8 {
const index = i.*;
if (expression.len - index < len) return error.EndOfStream;
i.* = index + len;
return expression[index..][0..len];
}
fn nextLeb128(expression: []const u8, i: *usize, comptime I: type) !I {
var br: std.io.Reader = .fixed(expression);
br.seek = i.*;
assert(br.seek <= br.end);
const result = br.takeLeb128(I) catch |err| switch (err) {
error.ReadFailed => unreachable,
else => |e| return e,
};
i.* = br.seek;
return result;
}
fn accessAddress(size: u8, addr: Address, accessor: ?*std.debug.MemoryAccessor) !Address {
if (accessor) |memory_accessor| {
switch (size) {
1 => if (memory_accessor.load(u8, addr) == null) return error.InvalidExpression,
2 => if (memory_accessor.load(u16, addr) == null) return error.InvalidExpression,
4 => if (memory_accessor.load(u32, addr) == null) return error.InvalidExpression,
8 => if (memory_accessor.load(u64, addr) == null) return error.InvalidExpression,
else => return error.InvalidExpression,
}
}
return switch (size) {
1 => std.math.cast(Address, @as(*const u8, @ptrFromInt(addr)).*),
2 => std.math.cast(Address, @as(*const u16, @ptrFromInt(addr)).*),
4 => std.math.cast(Address, @as(*const u32, @ptrFromInt(addr)).*),
8 => std.math.cast(Address, @as(*const u64, @ptrFromInt(addr)).*),
else => return error.InvalidExpression,
} orelse return error.InvalidExpression;
}
fn cmpOp(stack: *std.ArrayListUnmanaged(Value), op: std.math.CompareOperator) !void {
if (stack.items.len < 2) return error.InvalidExpression;
const a = stack.pop().?;
const b = stack.items[stack.items.len - 1];
const a_int = try a.asIntegral();
const b_int = try b.asIntegral();
stack.items[stack.items.len - 1] = .{ .generic = @intFromBool(std.math.compare(a_int, op, b_int)) };
}
};
}
pub fn Builder(comptime options: Options) type {
const Address = switch (options.addr_size) {
2 => u16,
4 => u32,
8 => u64,
else => @compileError("Unsupported address size of " ++ options.addr_size),
};
return struct {
/// Zero-operand instructions
pub fn writeOpcode(writer: *Writer, comptime opcode: u8) !void {
if (options.call_frame_context and !comptime isOpcodeValidInCFA(opcode)) return error.InvalidCFAOpcode;
switch (opcode) {
OP.dup,
OP.drop,
OP.over,
OP.swap,
OP.rot,
OP.deref,
OP.xderef,
OP.push_object_address,
OP.form_tls_address,
OP.call_frame_cfa,
OP.abs,
OP.@"and",
OP.div,
OP.minus,
OP.mod,
OP.mul,
OP.neg,
OP.not,
OP.@"or",
OP.plus,
OP.shl,
OP.shr,
OP.shra,
OP.xor,
OP.le,
OP.ge,
OP.eq,
OP.lt,
OP.gt,
OP.ne,
OP.nop,
OP.stack_value,
=> try writer.writeByte(opcode),
else => @compileError("This opcode requires operands, use `write<Opcode>()` instead"),
}
}
// 2.5.1.1: Literal Encodings
pub fn writeLiteral(writer: *Writer, literal: u8) !void {
switch (literal) {
0...31 => |n| try writer.writeByte(n + OP.lit0),
else => return error.InvalidLiteral,
}
}
pub fn writeConst(writer: *Writer, comptime T: type, value: T) !void {
if (@typeInfo(T) != .int) @compileError("Constants must be integers");
switch (T) {
u8, i8, u16, i16, u32, i32, u64, i64 => {
try writer.writeByte(switch (T) {
u8 => OP.const1u,
i8 => OP.const1s,
u16 => OP.const2u,
i16 => OP.const2s,
u32 => OP.const4u,
i32 => OP.const4s,
u64 => OP.const8u,
i64 => OP.const8s,
else => unreachable,
});
try writer.writeInt(T, value, options.endian);
},
else => switch (@typeInfo(T).int.signedness) {
.unsigned => {
try writer.writeByte(OP.constu);
try leb.writeUleb128(writer, value);
},
.signed => {
try writer.writeByte(OP.consts);
try leb.writeIleb128(writer, value);
},
},
}
}
pub fn writeConstx(writer: *Writer, debug_addr_offset: anytype) !void {
try writer.writeByte(OP.constx);
try leb.writeUleb128(writer, debug_addr_offset);
}
pub fn writeConstType(writer: *Writer, die_offset: anytype, value_bytes: []const u8) !void {
if (options.call_frame_context) return error.InvalidCFAOpcode;
if (value_bytes.len > 0xff) return error.InvalidTypeLength;
try writer.writeByte(OP.const_type);
try leb.writeUleb128(writer, die_offset);
try writer.writeByte(@intCast(value_bytes.len));
try writer.writeAll(value_bytes);
}
pub fn writeAddr(writer: *Writer, value: Address) !void {
try writer.writeByte(OP.addr);
try writer.writeInt(Address, value, options.endian);
}
pub fn writeAddrx(writer: *Writer, debug_addr_offset: anytype) !void {
if (options.call_frame_context) return error.InvalidCFAOpcode;
try writer.writeByte(OP.addrx);
try leb.writeUleb128(writer, debug_addr_offset);
}
// 2.5.1.2: Register Values
pub fn writeFbreg(writer: *Writer, offset: anytype) !void {
try writer.writeByte(OP.fbreg);
try leb.writeIleb128(writer, offset);
}
pub fn writeBreg(writer: *Writer, register: u8, offset: anytype) !void {
if (register > 31) return error.InvalidRegister;
try writer.writeByte(OP.breg0 + register);
try leb.writeIleb128(writer, offset);
}
pub fn writeBregx(writer: *Writer, register: anytype, offset: anytype) !void {
try writer.writeByte(OP.bregx);
try leb.writeUleb128(writer, register);
try leb.writeIleb128(writer, offset);
}
pub fn writeRegvalType(writer: *Writer, register: anytype, offset: anytype) !void {
if (options.call_frame_context) return error.InvalidCFAOpcode;
try writer.writeByte(OP.regval_type);
try leb.writeUleb128(writer, register);
try leb.writeUleb128(writer, offset);
}
// 2.5.1.3: Stack Operations
pub fn writePick(writer: *Writer, index: u8) !void {
try writer.writeByte(OP.pick);
try writer.writeByte(index);
}
pub fn writeDerefSize(writer: *Writer, size: u8) !void {
try writer.writeByte(OP.deref_size);
try writer.writeByte(size);
}
pub fn writeXDerefSize(writer: *Writer, size: u8) !void {
try writer.writeByte(OP.xderef_size);
try writer.writeByte(size);
}
pub fn writeDerefType(writer: *Writer, size: u8, die_offset: anytype) !void {
if (options.call_frame_context) return error.InvalidCFAOpcode;
try writer.writeByte(OP.deref_type);
try writer.writeByte(size);
try leb.writeUleb128(writer, die_offset);
}
pub fn writeXDerefType(writer: *Writer, size: u8, die_offset: anytype) !void {
try writer.writeByte(OP.xderef_type);
try writer.writeByte(size);
try leb.writeUleb128(writer, die_offset);
}
// 2.5.1.4: Arithmetic and Logical Operations
pub fn writePlusUconst(writer: *Writer, uint_value: anytype) !void {
try writer.writeByte(OP.plus_uconst);
try leb.writeUleb128(writer, uint_value);
}
// 2.5.1.5: Control Flow Operations
pub fn writeSkip(writer: *Writer, offset: i16) !void {
try writer.writeByte(OP.skip);
try writer.writeInt(i16, offset, options.endian);
}
pub fn writeBra(writer: *Writer, offset: i16) !void {
try writer.writeByte(OP.bra);
try writer.writeInt(i16, offset, options.endian);
}
pub fn writeCall(writer: *Writer, comptime T: type, offset: T) !void {
if (options.call_frame_context) return error.InvalidCFAOpcode;
switch (T) {
u16 => try writer.writeByte(OP.call2),
u32 => try writer.writeByte(OP.call4),
else => @compileError("Call operand must be a 2 or 4 byte offset"),
}
try writer.writeInt(T, offset, options.endian);
}
pub fn writeCallRef(writer: *Writer, comptime is_64: bool, value: if (is_64) u64 else u32) !void {
if (options.call_frame_context) return error.InvalidCFAOpcode;
try writer.writeByte(OP.call_ref);
try writer.writeInt(if (is_64) u64 else u32, value, options.endian);
}
pub fn writeConvert(writer: *Writer, die_offset: anytype) !void {
if (options.call_frame_context) return error.InvalidCFAOpcode;
try writer.writeByte(OP.convert);
try leb.writeUleb128(writer, die_offset);
}
pub fn writeReinterpret(writer: *Writer, die_offset: anytype) !void {
if (options.call_frame_context) return error.InvalidCFAOpcode;
try writer.writeByte(OP.reinterpret);
try leb.writeUleb128(writer, die_offset);
}
// 2.5.1.7: Special Operations
pub fn writeEntryValue(writer: *Writer, expression: []const u8) !void {
try writer.writeByte(OP.entry_value);
try leb.writeUleb128(writer, expression.len);
try writer.writeAll(expression);
}
// 2.6: Location Descriptions
pub fn writeReg(writer: *Writer, register: u8) !void {
try writer.writeByte(OP.reg0 + register);
}
pub fn writeRegx(writer: *Writer, register: anytype) !void {
try writer.writeByte(OP.regx);
try leb.writeUleb128(writer, register);
}
pub fn writeImplicitValue(writer: *Writer, value_bytes: []const u8) !void {
try writer.writeByte(OP.implicit_value);
try leb.writeUleb128(writer, value_bytes.len);
try writer.writeAll(value_bytes);
}
};
}
/// Certain opcodes are not allowed in a CFA context, see 6.4.2
fn isOpcodeValidInCFA(opcode: OP) bool {
return switch (opcode) {
.addrx,
.call2,
.call4,
.call_ref,
.const_type,
.constx,
.convert,
.deref_type,
.regval_type,
.reinterpret,
.push_object_address,
.call_frame_cfa,
=> false,
else => true,
};
}
fn isOpcodeRegisterLocation(opcode: u8) bool {
return switch (opcode) {
OP.reg0...OP.reg31, OP.regx => true,
else => false,
};
}
const testing = std.testing;
test "DWARF expressions" {
const allocator = std.testing.allocator;
const options = Options{};
var stack_machine = StackMachine(options){};
defer stack_machine.deinit(allocator);
const b = Builder(options);
var program = std.ArrayList(u8).init(allocator);
defer program.deinit();
const writer = program.writer();
// Literals
{
const context = Context{};
for (0..32) |i| {
try b.writeLiteral(writer, @intCast(i));
}
_ = try stack_machine.run(program.items, allocator, context, 0);
for (0..32) |i| {
const expected = 31 - i;
try testing.expectEqual(expected, stack_machine.stack.pop().?.generic);
}
}
// Constants
{
stack_machine.reset();
program.clearRetainingCapacity();
const input = [_]comptime_int{
1,
-1,
@as(usize, @truncate(0x0fff)),
@as(isize, @truncate(-0x0fff)),
@as(usize, @truncate(0x0fffffff)),
@as(isize, @truncate(-0x0fffffff)),
@as(usize, @truncate(0x0fffffffffffffff)),
@as(isize, @truncate(-0x0fffffffffffffff)),
@as(usize, @truncate(0x8000000)),
@as(isize, @truncate(-0x8000000)),
@as(usize, @truncate(0x12345678_12345678)),
@as(usize, @truncate(0xffffffff_ffffffff)),
@as(usize, @truncate(0xeeeeeeee_eeeeeeee)),
};
try b.writeConst(writer, u8, input[0]);
try b.writeConst(writer, i8, input[1]);
try b.writeConst(writer, u16, input[2]);
try b.writeConst(writer, i16, input[3]);
try b.writeConst(writer, u32, input[4]);
try b.writeConst(writer, i32, input[5]);
try b.writeConst(writer, u64, input[6]);
try b.writeConst(writer, i64, input[7]);
try b.writeConst(writer, u28, input[8]);
try b.writeConst(writer, i28, input[9]);
try b.writeAddr(writer, input[10]);
var mock_compile_unit: std.debug.Dwarf.CompileUnit = undefined;
mock_compile_unit.addr_base = 1;
var mock_debug_addr = std.ArrayList(u8).init(allocator);
defer mock_debug_addr.deinit();
try mock_debug_addr.writer().writeInt(u16, 0, native_endian);
try mock_debug_addr.writer().writeInt(usize, input[11], native_endian);
try mock_debug_addr.writer().writeInt(usize, input[12], native_endian);
const context = Context{
.compile_unit = &mock_compile_unit,
.debug_addr = mock_debug_addr.items,
};
try b.writeConstx(writer, @as(usize, 1));
try b.writeAddrx(writer, @as(usize, 1 + @sizeOf(usize)));
const die_offset: usize = @truncate(0xaabbccdd);
const type_bytes: []const u8 = &.{ 1, 2, 3, 4 };
try b.writeConstType(writer, die_offset, type_bytes);
_ = try stack_machine.run(program.items, allocator, context, 0);
const const_type = stack_machine.stack.pop().?.const_type;
try testing.expectEqual(die_offset, const_type.type_offset);
try testing.expectEqualSlices(u8, type_bytes, const_type.value_bytes);
const expected = .{
.{ usize, input[12], usize },
.{ usize, input[11], usize },
.{ usize, input[10], usize },
.{ isize, input[9], isize },
.{ usize, input[8], usize },
.{ isize, input[7], isize },
.{ usize, input[6], usize },
.{ isize, input[5], isize },
.{ usize, input[4], usize },
.{ isize, input[3], isize },
.{ usize, input[2], usize },
.{ isize, input[1], isize },
.{ usize, input[0], usize },
};
inline for (expected) |e| {
try testing.expectEqual(@as(e[0], e[1]), @as(e[2], @bitCast(stack_machine.stack.pop().?.generic)));
}
}
// Register values
if (@sizeOf(std.debug.ThreadContext) != 0) {
stack_machine.reset();
program.clearRetainingCapacity();
const reg_context = abi.RegisterContext{
.eh_frame = true,
.is_macho = builtin.os.tag == .macos,
};
var thread_context: std.debug.ThreadContext = undefined;
std.debug.relocateContext(&thread_context);
const context = Context{
.thread_context = &thread_context,
.reg_context = reg_context,
};
// Only test register operations on arch / os that have them implemented
if (abi.regBytes(&thread_context, 0, reg_context)) |reg_bytes| {
// TODO: Test fbreg (once implemented): mock a DIE and point compile_unit.frame_base at it
mem.writeInt(usize, reg_bytes[0..@sizeOf(usize)], 0xee, native_endian);
(try abi.regValueNative(&thread_context, abi.fpRegNum(native_arch, reg_context), reg_context)).* = 1;
(try abi.regValueNative(&thread_context, abi.spRegNum(native_arch, reg_context), reg_context)).* = 2;
(try abi.regValueNative(&thread_context, abi.ipRegNum(native_arch).?, reg_context)).* = 3;
try b.writeBreg(writer, abi.fpRegNum(native_arch, reg_context), @as(usize, 100));
try b.writeBreg(writer, abi.spRegNum(native_arch, reg_context), @as(usize, 200));
try b.writeBregx(writer, abi.ipRegNum(native_arch).?, @as(usize, 300));
try b.writeRegvalType(writer, @as(u8, 0), @as(usize, 400));
_ = try stack_machine.run(program.items, allocator, context, 0);
const regval_type = stack_machine.stack.pop().?.regval_type;
try testing.expectEqual(@as(usize, 400), regval_type.type_offset);
try testing.expectEqual(@as(u8, @sizeOf(usize)), regval_type.type_size);
try testing.expectEqual(@as(usize, 0xee), regval_type.value);
try testing.expectEqual(@as(usize, 303), stack_machine.stack.pop().?.generic);
try testing.expectEqual(@as(usize, 202), stack_machine.stack.pop().?.generic);
try testing.expectEqual(@as(usize, 101), stack_machine.stack.pop().?.generic);
} else |err| {
switch (err) {
error.UnimplementedArch,
error.UnimplementedOs,
error.ThreadContextNotSupported,
=> {},
else => return err,
}
}
}
// Stack operations
{
var context = Context{};
stack_machine.reset();
program.clearRetainingCapacity();
try b.writeConst(writer, u8, 1);
try b.writeOpcode(writer, OP.dup);
_ = try stack_machine.run(program.items, allocator, context, null);
try testing.expectEqual(@as(usize, 1), stack_machine.stack.pop().?.generic);
try testing.expectEqual(@as(usize, 1), stack_machine.stack.pop().?.generic);
stack_machine.reset();
program.clearRetainingCapacity();
try b.writeConst(writer, u8, 1);
try b.writeOpcode(writer, OP.drop);
_ = try stack_machine.run(program.items, allocator, context, null);
try testing.expect(stack_machine.stack.pop() == null);
stack_machine.reset();
program.clearRetainingCapacity();
try b.writeConst(writer, u8, 4);
try b.writeConst(writer, u8, 5);
try b.writeConst(writer, u8, 6);
try b.writePick(writer, 2);
_ = try stack_machine.run(program.items, allocator, context, null);
try testing.expectEqual(@as(usize, 4), stack_machine.stack.pop().?.generic);
stack_machine.reset();
program.clearRetainingCapacity();
try b.writeConst(writer, u8, 4);
try b.writeConst(writer, u8, 5);
try b.writeConst(writer, u8, 6);
try b.writeOpcode(writer, OP.over);
_ = try stack_machine.run(program.items, allocator, context, null);
try testing.expectEqual(@as(usize, 5), stack_machine.stack.pop().?.generic);
stack_machine.reset();
program.clearRetainingCapacity();
try b.writeConst(writer, u8, 5);
try b.writeConst(writer, u8, 6);
try b.writeOpcode(writer, OP.swap);
_ = try stack_machine.run(program.items, allocator, context, null);
try testing.expectEqual(@as(usize, 5), stack_machine.stack.pop().?.generic);
try testing.expectEqual(@as(usize, 6), stack_machine.stack.pop().?.generic);
stack_machine.reset();
program.clearRetainingCapacity();
try b.writeConst(writer, u8, 4);
try b.writeConst(writer, u8, 5);
try b.writeConst(writer, u8, 6);
try b.writeOpcode(writer, OP.rot);
_ = try stack_machine.run(program.items, allocator, context, null);
try testing.expectEqual(@as(usize, 5), stack_machine.stack.pop().?.generic);
try testing.expectEqual(@as(usize, 4), stack_machine.stack.pop().?.generic);
try testing.expectEqual(@as(usize, 6), stack_machine.stack.pop().?.generic);
const deref_target: usize = @truncate(0xffeeffee_ffeeffee);
stack_machine.reset();
program.clearRetainingCapacity();
try b.writeAddr(writer, @intFromPtr(&deref_target));
try b.writeOpcode(writer, OP.deref);
_ = try stack_machine.run(program.items, allocator, context, null);
try testing.expectEqual(deref_target, stack_machine.stack.pop().?.generic);
stack_machine.reset();
program.clearRetainingCapacity();
try b.writeLiteral(writer, 0);
try b.writeAddr(writer, @intFromPtr(&deref_target));
try b.writeOpcode(writer, OP.xderef);
_ = try stack_machine.run(program.items, allocator, context, null);
try testing.expectEqual(deref_target, stack_machine.stack.pop().?.generic);
stack_machine.reset();
program.clearRetainingCapacity();
try b.writeAddr(writer, @intFromPtr(&deref_target));
try b.writeDerefSize(writer, 1);
_ = try stack_machine.run(program.items, allocator, context, null);
try testing.expectEqual(@as(usize, @as(*const u8, @ptrCast(&deref_target)).*), stack_machine.stack.pop().?.generic);
stack_machine.reset();
program.clearRetainingCapacity();
try b.writeLiteral(writer, 0);
try b.writeAddr(writer, @intFromPtr(&deref_target));
try b.writeXDerefSize(writer, 1);
_ = try stack_machine.run(program.items, allocator, context, null);
try testing.expectEqual(@as(usize, @as(*const u8, @ptrCast(&deref_target)).*), stack_machine.stack.pop().?.generic);
const type_offset: usize = @truncate(0xaabbaabb_aabbaabb);
stack_machine.reset();
program.clearRetainingCapacity();
try b.writeAddr(writer, @intFromPtr(&deref_target));
try b.writeDerefType(writer, 1, type_offset);
_ = try stack_machine.run(program.items, allocator, context, null);
const deref_type = stack_machine.stack.pop().?.regval_type;
try testing.expectEqual(type_offset, deref_type.type_offset);
try testing.expectEqual(@as(u8, 1), deref_type.type_size);
try testing.expectEqual(@as(usize, @as(*const u8, @ptrCast(&deref_target)).*), deref_type.value);
stack_machine.reset();
program.clearRetainingCapacity();
try b.writeLiteral(writer, 0);
try b.writeAddr(writer, @intFromPtr(&deref_target));
try b.writeXDerefType(writer, 1, type_offset);
_ = try stack_machine.run(program.items, allocator, context, null);
const xderef_type = stack_machine.stack.pop().?.regval_type;
try testing.expectEqual(type_offset, xderef_type.type_offset);
try testing.expectEqual(@as(u8, 1), xderef_type.type_size);
try testing.expectEqual(@as(usize, @as(*const u8, @ptrCast(&deref_target)).*), xderef_type.value);
context.object_address = &deref_target;
stack_machine.reset();
program.clearRetainingCapacity();
try b.writeOpcode(writer, OP.push_object_address);
_ = try stack_machine.run(program.items, allocator, context, null);
try testing.expectEqual(@as(usize, @intFromPtr(context.object_address.?)), stack_machine.stack.pop().?.generic);
// TODO: Test OP.form_tls_address
context.cfa = @truncate(0xccddccdd_ccddccdd);
stack_machine.reset();
program.clearRetainingCapacity();
try b.writeOpcode(writer, OP.call_frame_cfa);
_ = try stack_machine.run(program.items, allocator, context, null);
try testing.expectEqual(context.cfa.?, stack_machine.stack.pop().?.generic);
}
// Arithmetic and Logical Operations
{
const context = Context{};
stack_machine.reset();
program.clearRetainingCapacity();
try b.writeConst(writer, i16, -4096);
try b.writeOpcode(writer, OP.abs);
_ = try stack_machine.run(program.items, allocator, context, null);
try testing.expectEqual(@as(usize, 4096), stack_machine.stack.pop().?.generic);
stack_machine.reset();
program.clearRetainingCapacity();
try b.writeConst(writer, u16, 0xff0f);
try b.writeConst(writer, u16, 0xf0ff);
try b.writeOpcode(writer, OP.@"and");
_ = try stack_machine.run(program.items, allocator, context, null);
try testing.expectEqual(@as(usize, 0xf00f), stack_machine.stack.pop().?.generic);
stack_machine.reset();
program.clearRetainingCapacity();
try b.writeConst(writer, i16, -404);
try b.writeConst(writer, i16, 100);
try b.writeOpcode(writer, OP.div);
_ = try stack_machine.run(program.items, allocator, context, null);
try testing.expectEqual(@as(isize, -404 / 100), @as(isize, @bitCast(stack_machine.stack.pop().?.generic)));
stack_machine.reset();
program.clearRetainingCapacity();
try b.writeConst(writer, u16, 200);
try b.writeConst(writer, u16, 50);
try b.writeOpcode(writer, OP.minus);
_ = try stack_machine.run(program.items, allocator, context, null);
try testing.expectEqual(@as(usize, 150), stack_machine.stack.pop().?.generic);
stack_machine.reset();
program.clearRetainingCapacity();
try b.writeConst(writer, u16, 123);
try b.writeConst(writer, u16, 100);
try b.writeOpcode(writer, OP.mod);
_ = try stack_machine.run(program.items, allocator, context, null);
try testing.expectEqual(@as(usize, 23), stack_machine.stack.pop().?.generic);
stack_machine.reset();
program.clearRetainingCapacity();
try b.writeConst(writer, u16, 0xff);
try b.writeConst(writer, u16, 0xee);
try b.writeOpcode(writer, OP.mul);
_ = try stack_machine.run(program.items, allocator, context, null);
try testing.expectEqual(@as(usize, 0xed12), stack_machine.stack.pop().?.generic);
stack_machine.reset();
program.clearRetainingCapacity();
try b.writeConst(writer, u16, 5);
try b.writeOpcode(writer, OP.neg);
try b.writeConst(writer, i16, -6);
try b.writeOpcode(writer, OP.neg);
_ = try stack_machine.run(program.items, allocator, context, null);
try testing.expectEqual(@as(usize, 6), stack_machine.stack.pop().?.generic);
try testing.expectEqual(@as(isize, -5), @as(isize, @bitCast(stack_machine.stack.pop().?.generic)));
stack_machine.reset();
program.clearRetainingCapacity();
try b.writeConst(writer, u16, 0xff0f);
try b.writeOpcode(writer, OP.not);
_ = try stack_machine.run(program.items, allocator, context, null);
try testing.expectEqual(~@as(usize, 0xff0f), stack_machine.stack.pop().?.generic);
stack_machine.reset();
program.clearRetainingCapacity();
try b.writeConst(writer, u16, 0xff0f);
try b.writeConst(writer, u16, 0xf0ff);
try b.writeOpcode(writer, OP.@"or");
_ = try stack_machine.run(program.items, allocator, context, null);
try testing.expectEqual(@as(usize, 0xffff), stack_machine.stack.pop().?.generic);
stack_machine.reset();
program.clearRetainingCapacity();
try b.writeConst(writer, i16, 402);
try b.writeConst(writer, i16, 100);
try b.writeOpcode(writer, OP.plus);
_ = try stack_machine.run(program.items, allocator, context, null);
try testing.expectEqual(@as(usize, 502), stack_machine.stack.pop().?.generic);
stack_machine.reset();
program.clearRetainingCapacity();
try b.writeConst(writer, u16, 4096);
try b.writePlusUconst(writer, @as(usize, 8192));
_ = try stack_machine.run(program.items, allocator, context, null);
try testing.expectEqual(@as(usize, 4096 + 8192), stack_machine.stack.pop().?.generic);
stack_machine.reset();
program.clearRetainingCapacity();
try b.writeConst(writer, u16, 0xfff);
try b.writeConst(writer, u16, 1);
try b.writeOpcode(writer, OP.shl);
_ = try stack_machine.run(program.items, allocator, context, null);
try testing.expectEqual(@as(usize, 0xfff << 1), stack_machine.stack.pop().?.generic);
stack_machine.reset();
program.clearRetainingCapacity();
try b.writeConst(writer, u16, 0xfff);
try b.writeConst(writer, u16, 1);
try b.writeOpcode(writer, OP.shr);
_ = try stack_machine.run(program.items, allocator, context, null);
try testing.expectEqual(@as(usize, 0xfff >> 1), stack_machine.stack.pop().?.generic);
stack_machine.reset();
program.clearRetainingCapacity();
try b.writeConst(writer, u16, 0xfff);
try b.writeConst(writer, u16, 1);
try b.writeOpcode(writer, OP.shr);
_ = try stack_machine.run(program.items, allocator, context, null);
try testing.expectEqual(@as(usize, @bitCast(@as(isize, 0xfff) >> 1)), stack_machine.stack.pop().?.generic);
stack_machine.reset();
program.clearRetainingCapacity();
try b.writeConst(writer, u16, 0xf0ff);
try b.writeConst(writer, u16, 0xff0f);
try b.writeOpcode(writer, OP.xor);
_ = try stack_machine.run(program.items, allocator, context, null);
try testing.expectEqual(@as(usize, 0x0ff0), stack_machine.stack.pop().?.generic);
}
// Control Flow Operations
{
const context = Context{};
const expected = .{
.{ OP.le, 1, 1, 0 },
.{ OP.ge, 1, 0, 1 },
.{ OP.eq, 1, 0, 0 },
.{ OP.lt, 0, 1, 0 },
.{ OP.gt, 0, 0, 1 },
.{ OP.ne, 0, 1, 1 },
};
inline for (expected) |e| {
stack_machine.reset();
program.clearRetainingCapacity();
try b.writeConst(writer, u16, 0);
try b.writeConst(writer, u16, 0);
try b.writeOpcode(writer, e[0]);
try b.writeConst(writer, u16, 0);
try b.writeConst(writer, u16, 1);
try b.writeOpcode(writer, e[0]);
try b.writeConst(writer, u16, 1);
try b.writeConst(writer, u16, 0);
try b.writeOpcode(writer, e[0]);
_ = try stack_machine.run(program.items, allocator, context, null);
try testing.expectEqual(@as(usize, e[3]), stack_machine.stack.pop().?.generic);
try testing.expectEqual(@as(usize, e[2]), stack_machine.stack.pop().?.generic);
try testing.expectEqual(@as(usize, e[1]), stack_machine.stack.pop().?.generic);
}
stack_machine.reset();
program.clearRetainingCapacity();
try b.writeLiteral(writer, 2);
try b.writeSkip(writer, 1);
try b.writeLiteral(writer, 3);
_ = try stack_machine.run(program.items, allocator, context, null);
try testing.expectEqual(@as(usize, 2), stack_machine.stack.pop().?.generic);
stack_machine.reset();
program.clearRetainingCapacity();
try b.writeLiteral(writer, 2);
try b.writeBra(writer, 1);
try b.writeLiteral(writer, 3);
try b.writeLiteral(writer, 0);
try b.writeBra(writer, 1);
try b.writeLiteral(writer, 4);
try b.writeLiteral(writer, 5);
_ = try stack_machine.run(program.items, allocator, context, null);
try testing.expectEqual(@as(usize, 5), stack_machine.stack.pop().?.generic);
try testing.expectEqual(@as(usize, 4), stack_machine.stack.pop().?.generic);
try testing.expect(stack_machine.stack.pop() == null);
// TODO: Test call2, call4, call_ref once implemented
}
// Type conversions
{
const context = Context{};
stack_machine.reset();
program.clearRetainingCapacity();
// TODO: Test typed OP.convert once implemented
const value: usize = @truncate(0xffeeffee_ffeeffee);
var value_bytes: [options.addr_size]u8 = undefined;
mem.writeInt(usize, &value_bytes, value, native_endian);
// Convert to generic type
stack_machine.reset();
program.clearRetainingCapacity();
try b.writeConstType(writer, @as(usize, 0), &value_bytes);
try b.writeConvert(writer, @as(usize, 0));
_ = try stack_machine.run(program.items, allocator, context, null);
try testing.expectEqual(value, stack_machine.stack.pop().?.generic);
// Reinterpret to generic type
stack_machine.reset();
program.clearRetainingCapacity();
try b.writeConstType(writer, @as(usize, 0), &value_bytes);
try b.writeReinterpret(writer, @as(usize, 0));
_ = try stack_machine.run(program.items, allocator, context, null);
try testing.expectEqual(value, stack_machine.stack.pop().?.generic);
// Reinterpret to new type
const die_offset: usize = 0xffee;
stack_machine.reset();
program.clearRetainingCapacity();
try b.writeConstType(writer, @as(usize, 0), &value_bytes);
try b.writeReinterpret(writer, die_offset);
_ = try stack_machine.run(program.items, allocator, context, null);
const const_type = stack_machine.stack.pop().?.const_type;
try testing.expectEqual(die_offset, const_type.type_offset);
stack_machine.reset();
program.clearRetainingCapacity();
try b.writeLiteral(writer, 0);
try b.writeReinterpret(writer, die_offset);
_ = try stack_machine.run(program.items, allocator, context, null);
const regval_type = stack_machine.stack.pop().?.regval_type;
try testing.expectEqual(die_offset, regval_type.type_offset);
}
// Special operations
{
var context = Context{};
stack_machine.reset();
program.clearRetainingCapacity();
try b.writeOpcode(writer, OP.nop);
_ = try stack_machine.run(program.items, allocator, context, null);
try testing.expect(stack_machine.stack.pop() == null);
// Sub-expression
{
var sub_program = std.ArrayList(u8).init(allocator);
defer sub_program.deinit();
const sub_writer = sub_program.writer();
try b.writeLiteral(sub_writer, 3);
stack_machine.reset();
program.clearRetainingCapacity();
try b.writeEntryValue(writer, sub_program.items);
_ = try stack_machine.run(program.items, allocator, context, null);
try testing.expectEqual(@as(usize, 3), stack_machine.stack.pop().?.generic);
}
// Register location description
const reg_context = abi.RegisterContext{
.eh_frame = true,
.is_macho = builtin.os.tag == .macos,
};
var thread_context: std.debug.ThreadContext = undefined;
std.debug.relocateContext(&thread_context);
context = Context{
.thread_context = &thread_context,
.reg_context = reg_context,
};
if (abi.regBytes(&thread_context, 0, reg_context)) |reg_bytes| {
mem.writeInt(usize, reg_bytes[0..@sizeOf(usize)], 0xee, native_endian);
var sub_program = std.ArrayList(u8).init(allocator);
defer sub_program.deinit();
const sub_writer = sub_program.writer();
try b.writeReg(sub_writer, 0);
stack_machine.reset();
program.clearRetainingCapacity();
try b.writeEntryValue(writer, sub_program.items);
_ = try stack_machine.run(program.items, allocator, context, null);
try testing.expectEqual(@as(usize, 0xee), stack_machine.stack.pop().?.generic);
} else |err| {
switch (err) {
error.UnimplementedArch,
error.UnimplementedOs,
error.ThreadContextNotSupported,
=> {},
else => return err,
}
}
}
}