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stage2: Support modifiers in inline asm

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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
This commit is contained in:
Cody Tapscott 2022-11-10 14:02:05 -07:00 committed by Andrew Kelley
parent 48798da29b
commit bc33243650
2 changed files with 33 additions and 3 deletions
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23
src/codegen/llvm.zig
View File

@ -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 => {},
},

13
test/behavior/asm.zig
View File

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