authorgravatar for kubkon@jakubkonka.comJakub Konka <kubkon@jakubkonka.com> 2021-11-21 17:00:00+01:00
committergravatar for kubkon@jakubkonka.comJakub Konka <kubkon@jakubkonka.com> 2021-11-21 20:43:10+01:00
log110c18588688e4c03010e372668bbb0ab90e4735
tree94b6ff036bb2c2c723fdd258cf3a7280e49348c1
parentc6b4fe00660d00d0748dc01f660ed7ac24f54db0

stage2: add x86_64 NOP MIR inst and lowering

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 {...@@ -405,6 +405,12 @@ fn gen(self: *Self) InnerError!void {
405 const aligned_stack_end = mem.alignForward(stack_end, self.stack_align);405 const aligned_stack_end = mem.alignForward(stack_end, self.stack_align);
406 if (aligned_stack_end > 0) {406 if (aligned_stack_end > 0) {
407 self.mir_instructions.items(.data)[backpatch_reloc].imm = @intCast(i32, aligned_stack_end);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 }
409415
410 if (self.exitlude_jump_relocs.items.len == 1) {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 {...@@ -134,6 +134,7 @@ pub fn emitMir(emit: *Emit) InnerError!void {
134 .@"test" => try emit.mirTest(inst),134 .@"test" => try emit.mirTest(inst),
135135
136 .brk => try emit.mirBrk(),136 .brk => try emit.mirBrk(),
137 .nop => try emit.mirNop(),
137138
138 .call_extern => try emit.mirCallExtern(inst),139 .call_extern => try emit.mirCallExtern(inst),
139140
...@@ -185,6 +186,11 @@ fn mirBrk(emit: *Emit) InnerError!void {...@@ -185,6 +186,11 @@ fn mirBrk(emit: *Emit) InnerError!void {
185 encoder.opcode_1byte(0xcc);186 encoder.opcode_1byte(0xcc);
186}187}
187188
189fn mirNop(emit: *Emit) InnerError!void {
190 const encoder = try Encoder.init(emit.code, 1);
191 encoder.opcode_1byte(0x90);
192}
193
188fn mirSyscall(emit: *Emit) InnerError!void {194fn mirSyscall(emit: *Emit) InnerError!void {
189 const encoder = try Encoder.init(emit.code, 2);195 const encoder = try Encoder.init(emit.code, 2);
190 encoder.opcode_2byte(0x0f, 0x05);196 encoder.opcode_2byte(0x0f, 0x05);
src/arch/x86_64/Mir.zig+3
...@@ -247,6 +247,9 @@ pub const Inst = struct {...@@ -247,6 +247,9 @@ pub const Inst = struct {
247 /// Breakpoint247 /// Breakpoint
248 brk,248 brk,
249249
250 /// Nop
251 nop,
252
250 /// Pseudo-instructions253 /// Pseudo-instructions
251 /// call extern function254 /// call extern function
252 /// Notes:255 /// Notes: