motiejus/zig
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x64: fix ptr_add

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However, still missing is taking into account pointer alignment
when performing arithmetic.
This commit is contained in:
Jakub Konka
2022-02-11 16:13:05 +01:00
parent c7775a9f62
commit 78e6f9c44c
3 changed files with 27 additions and 3 deletions
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28
src/arch/x86_64/CodeGen.zig
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@@ -2217,7 +2217,26 @@ fn genBinMathOp(self: *Self, inst: Air.Inst.Index, op_lhs: Air.Inst.Ref, op_rhs:
// Now for step 2, we assing an MIR instruction
const air_tags = self.air.instructions.items(.tag);
switch (air_tags[inst]) {
.add, .addwrap, .ptr_add => try self.genBinMathOpMir(.add, dst_ty, dst_mcv, src_mcv),
.ptr_add => {
// TODO clean this up
// TODO take into account alignment
const elem_size = dst_ty.elemType2().abiSize(self.target.*);
const dst_reg = blk: {
switch (dst_mcv) {
.register => |reg| break :blk reg,
else => {
src_mcv.freezeIfRegister(&self.register_manager);
defer src_mcv.freezeIfRegister(&self.register_manager);
const reg = try self.copyToTmpRegister(dst_ty, dst_mcv);
break :blk reg;
},
}
};
try self.genIMulOpMir(dst_ty, .{ .register = dst_reg }, .{ .immediate = elem_size });
dst_mcv = MCValue{ .register = dst_reg };
try self.genBinMathOpMir(.add, dst_ty, dst_mcv, src_mcv);
},
.add, .addwrap => try self.genBinMathOpMir(.add, dst_ty, dst_mcv, src_mcv),
.bool_or, .bit_or => try self.genBinMathOpMir(.@"or", dst_ty, dst_mcv, src_mcv),
.bool_and, .bit_and => try self.genBinMathOpMir(.@"and", dst_ty, dst_mcv, src_mcv),
.sub, .subwrap => try self.genBinMathOpMir(.sub, dst_ty, dst_mcv, src_mcv),
@@ -2244,8 +2263,11 @@ fn genBinMathOpMir(self: *Self, mir_tag: Mir.Inst.Tag, dst_ty: Type, dst_mcv: MC
.none => unreachable,
.undef => try self.genSetReg(dst_ty, dst_reg, .undef),
.dead, .unreach => unreachable,
.ptr_stack_offset => |off| {
return self.genBinMathOpMir(mir_tag, dst_ty, dst_mcv, .{ .immediate = @bitCast(u32, off) });
.ptr_stack_offset => {
self.register_manager.freezeRegs(&.{dst_reg});
defer self.register_manager.unfreezeRegs(&.{dst_reg});
const reg = try self.copyToTmpRegister(dst_ty, src_mcv);
return self.genBinMathOpMir(mir_tag, dst_ty, dst_mcv, .{ .register = reg });
},
.ptr_embedded_in_code => unreachable,
.register => |src_reg| {

1
test/behavior/align.zig
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@@ -106,6 +106,7 @@ fn fnWithAlignedStack() i32 {
test "implicitly decreasing slice alignment" {
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
const a: u32 align(4) = 3;
const b: u32 align(8) = 4;

1
test/behavior/array.zig
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@@ -8,6 +8,7 @@ const expectEqual = testing.expectEqual;
test "array to slice" {
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
const a: u32 align(4) = 3;
const b: u32 align(8) = 4;