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stage2/wasm: implement trivial codegen

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We now generate code for returning constants of any of the basic types.
This commit is contained in:
Isaac Freund 2020-08-16 01:10:08 +02:00
parent 3370b5f109
commit 97300896ed
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GPG Key ID: 86DED400DDFD7A11
1 changed files with 53 additions and 4 deletions
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57
src-self-hosted/codegen/wasm.zig
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@ -3,9 +3,12 @@ const Allocator = std.mem.Allocator;
const ArrayList = std.ArrayList;
const assert = std.debug.assert;
const leb = std.debug.leb;
const mem = std.mem;
const Decl = @import("../Module.zig").Decl;
const Inst = @import("../ir.zig").Inst;
const Type = @import("../type.zig").Type;
const Value = @import("../value.zig").Value;
fn genValtype(ty: Type) u8 {
return switch (ty.tag()) {
@ -56,10 +59,10 @@ pub fn genCode(buf: *ArrayList(u8), decl: *Decl) !void {
try leb.writeULEB128(writer, @as(u32, 0));
// Write instructions
// TODO: actually implement codegen
try writer.writeByte(0x41); // i32.const
try leb.writeILEB128(writer, @as(i32, 42));
// TODO: check for and handle death of instructions
const tv = decl.typed_value.most_recent.typed_value;
const mod_fn = tv.val.cast(Value.Payload.Function).?.func;
for (mod_fn.analysis.success.instructions) |inst| try genInst(writer, inst);
// Write 'end' opcode
try writer.writeByte(0x0B);
@ -68,3 +71,49 @@ pub fn genCode(buf: *ArrayList(u8), decl: *Decl) !void {
// beginning of the buffer.
leb.writeUnsignedFixed(5, buf.items[0..5], @intCast(u32, buf.items.len - 5));
}
fn genInst(writer: ArrayList(u8).Writer, inst: *Inst) !void {
return switch (inst.tag) {
.dbg_stmt => {},
.ret => genRet(writer, inst.castTag(.ret).?),
else => error.TODOImplementMoreWasmCodegen,
};
}
fn genRet(writer: ArrayList(u8).Writer, inst: *Inst.UnOp) !void {
switch (inst.operand.tag) {
.constant => {
const constant = inst.operand.castTag(.constant).?;
switch (inst.operand.ty.tag()) {
.u32 => {
try writer.writeByte(0x41); // i32.const
try leb.writeILEB128(writer, constant.val.toUnsignedInt());
},
.i32 => {
try writer.writeByte(0x41); // i32.const
try leb.writeILEB128(writer, constant.val.toSignedInt());
},
.u64 => {
try writer.writeByte(0x42); // i64.const
try leb.writeILEB128(writer, constant.val.toUnsignedInt());
},
.i64 => {
try writer.writeByte(0x42); // i64.const
try leb.writeILEB128(writer, constant.val.toSignedInt());
},
.f32 => {
try writer.writeByte(0x43); // f32.const
// TODO: enforce LE byte order
try writer.writeAll(mem.asBytes(&constant.val.toFloat(f32)));
},
.f64 => {
try writer.writeByte(0x44); // f64.const
// TODO: enforce LE byte order
try writer.writeAll(mem.asBytes(&constant.val.toFloat(f64)));
},
else => return error.TODOImplementMoreWasmCodegen,
}
},
else => return error.TODOImplementMoreWasmCodegen,
}
}