Commit bc3324365090f3c9077df147b52fbc0c3c19b753 | zig

author	Cody Tapscott <topolarity@tapscott.me> 2022-11-10 14:02:05-07:00
committer	Andrew Kelley <andrew@ziglang.org> 2023-01-09 14:00:11-07:00
log	bc3324365090f3c9077df147b52fbc0c3c19b753
tree	2df30175dbb4430ac32694add75597e4845f46d9
parent	48798da29b368cf934ed81eb19a6fbf5c5aa3de9

stage2: Support modifiers in inline asm

These are supported using %[ident:mod] syntax. This allows requesting,
e.g., the "w" (32-bit) vs. "x" (64-bit) views of AArch64 registers.

See https://llvm.org/docs/LangRef.html#asm-template-argument-modifiers

2 files changed, 33 insertions(+), 3 deletions(-)

src
- codegen
  - llvm.zig
test
- behavior
  - asm.zig

src/codegen/llvm.zig+20-3

 @@ -6290,11 +6290,12 @@ pub const FuncGen = struct {
         var rendered_template = std.ArrayList(u8).init(self.gpa);
         defer rendered_template.deinit();
-        const State = enum { start, percent, input };
+        const State = enum { start, percent, input, modifier };
         var state: State = .start;
         var name_start: usize = undefined;
+        var modifier_start: usize = undefined;
         for (asm_source) |byte, i| {
             switch (state) {
                 .start => switch (byte) {
 @@ -6309,6 +6310,7 @@ pub const FuncGen = struct {
                     },
                     '[' => {
                         try rendered_template.append('$');
+                        try rendered_template.append('{');
                         name_start = i + 1;
                         state = .input;
                     },
 @@ -6319,15 +6321,30 @@ pub const FuncGen = struct {
                     },
                 },
                 .input => switch (byte) {
-                    ']' => {
+                    ']', ':' => {
                         const name = asm_source[name_start..i];
-                        state = .start;
                         const index = name_map.get(name) orelse {
                             // we should validate the assembly in Sema; by now it is too late
                             return self.todo("unknown input or output name: '{s}'", .{name});
                         };
                         try rendered_template.writer().print("{d}", .{index});
+                        if (byte == ':') {
+                            try rendered_template.append(':');
+                            modifier_start = i + 1;
+                            state = .modifier;
+                        } else {
+                            try rendered_template.append('}');
+                            state = .start;
+                        }
+                    },
+                    else => {},
+                },
+                .modifier => switch (byte) {
+                    ']' => {
+                        try rendered_template.appendSlice(asm_source[modifier_start..i]);
+                        try rendered_template.append('}');
+                        state = .start;
                     },
                     else => {},
                 },

test/behavior/asm.zig+13

...	@@ -136,3 +136,16 @@ extern fn this_is_my_alias() i32;	...	@@ -136,3 +136,16 @@ extern fn this_is_my_alias() i32;
136	export fn derp() i32 {	136	export fn derp() i32 {
137	return 1234;	137	return 1234;
138	}	138	}
		139
		140	test "asm modifiers (AArch64)" {
		141	if (builtin.target.cpu.arch != .aarch64) return error.SkipZigTest;
		142	if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
		143	if (builtin.zig_backend == .stage2_c) return error.SkipZigTest; // TODO
		144
		145	var x: u32 = 15;
		146	const double = asm ("add %[ret:w], %[in:w], %[in:w]"
		147	: [ret] "=r" (-> u32),
		148	: [in] "r" (x),
		149	);
		150	try expect(double == 2 * x);
		151	}