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wasm: memcpy support elem abi-size > 1

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Previously it was incorrectly assumed that all memcopy's generated by
the `memcpy` AIR instruction had an element size of 1 byte. However,
this would result in miscompilations for pointer's to arrays where
the element size of the array was larger than 1 byte. We now corectly
calculate this size.
This commit is contained in:
Luuk de Gram 2023-05-21 15:16:48 +02:00
parent cd1417dbdf
commit 00dedabc41
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1 changed files with 14 additions and 2 deletions
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16
src/arch/wasm/CodeGen.zig
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@ -5295,11 +5295,23 @@ fn airMemcpy(func: *CodeGen, inst: Air.Inst.Index) InnerError!void {
const bin_op = func.air.instructions.items(.data)[inst].bin_op;
const dst = try func.resolveInst(bin_op.lhs);
const dst_ty = func.air.typeOf(bin_op.lhs);
const ptr_elem_ty = dst_ty.childType();
const src = try func.resolveInst(bin_op.rhs);
const src_ty = func.air.typeOf(bin_op.rhs);
const len = switch (dst_ty.ptrSize()) {
.Slice => try func.sliceLen(dst),
.One => @as(WValue, .{ .imm32 = @intCast(u32, dst_ty.childType().arrayLen()) }),
.Slice => blk: {
const slice_len = try func.sliceLen(dst);
if (ptr_elem_ty.abiSize(func.target) != 1) {
try func.emitWValue(slice_len);
try func.emitWValue(.{ .imm32 = @intCast(u32, ptr_elem_ty.abiSize(func.target)) });
try func.addTag(.i32_mul);
try func.addLabel(.local_set, slice_len.local.value);
}
break :blk slice_len;
},
.One => @as(WValue, .{
.imm32 = @intCast(u32, ptr_elem_ty.arrayLen() * ptr_elem_ty.childType().abiSize(func.target)),
}),
.C, .Many => unreachable,
};
const dst_ptr = try func.sliceOrArrayPtr(dst, dst_ty);