Commit 110c18588688e4c03010e372668bbb0ab90e4735 | zig

author	Jakub Konka <kubkon@jakubkonka.com> 2021-11-21 17:00:00+01:00
committer	Jakub Konka <kubkon@jakubkonka.com> 2021-11-21 20:43:10+01:00
log	110c18588688e4c03010e372668bbb0ab90e4735
tree	94b6ff036bb2c2c723fdd258cf3a7280e49348c1
parent	c6b4fe00660d00d0748dc01f660ed7ac24f54db0

If we don't touch the stack, ellide `sub rsp, imm32` to `nop`.

3 files changed, 15 insertions(+), 0 deletions(-)

src/arch/x86_64/CodeGen.zig+6

...	...	@@ -405,6 +405,12 @@ fn gen(self: *Self) InnerError!void {
405	405	const aligned_stack_end = mem.alignForward(stack_end, self.stack_align);
406	406	if (aligned_stack_end > 0) {
407	407	self.mir_instructions.items(.data)[backpatch_reloc].imm = @intCast(i32, aligned_stack_end);
	408	} else {
	409	self.mir_instructions.set(backpatch_reloc, .{
	410	.tag = .nop,
	411	.ops = undefined,
	412	.data = undefined,
	413	});
408	414	}
409	415
410	416	if (self.exitlude_jump_relocs.items.len == 1) {

src/arch/x86_64/Emit.zig+6

...	...	@@ -134,6 +134,7 @@ pub fn emitMir(emit: *Emit) InnerError!void {
134	134	.@"test" => try emit.mirTest(inst),
135	135
136	136	.brk => try emit.mirBrk(),
	137	.nop => try emit.mirNop(),
137	138
138	139	.call_extern => try emit.mirCallExtern(inst),
139	140
...	...	@@ -185,6 +186,11 @@ fn mirBrk(emit: *Emit) InnerError!void {
185	186	encoder.opcode_1byte(0xcc);
186	187	}
187	188
	189	fn mirNop(emit: *Emit) InnerError!void {
	190	const encoder = try Encoder.init(emit.code, 1);
	191	encoder.opcode_1byte(0x90);
	192	}
	193
188	194	fn mirSyscall(emit: *Emit) InnerError!void {
189	195	const encoder = try Encoder.init(emit.code, 2);
190	196	encoder.opcode_2byte(0x0f, 0x05);

src/arch/x86_64/Mir.zig+3