5f444aae26
Extends lowerAsmExpr with a pinnedRegister(constraint) helper and two §II.5
operand-naming checks, in the compile path before the codegen bail:
- reject the echo form `[eax] "={eax}"` — a label identical to the register its
own constraint pins is redundant (the operand is already auto-named after the
register); the useful form is a label that differs (`[quot] "={rax}"`);
- reject duplicate operand names (ambiguous %[name] / result field).
Locked with 1643-platform-asm-echo-name and 1644-platform-asm-duplicate-name.
zig build test green (652 corpus, 445 unit).
7 lines
430 B
Plaintext
7 lines
430 B
Plaintext
// ASM stream Phase B — operand naming rule (§II.5): an explicit `[name]` that
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// just echoes the register its own constraint pins (`[eax] "={eax}"`) carries
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// no information — the operand is already auto-named after the register. Reject
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// it. The useful form is a label that DIFFERS (e.g. `[quot] "={rax}"`).
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f :: () -> u32 { return asm volatile { "cpuid", [eax] "={eax}" -> u32, "{eax}" = 1 }; }
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main :: () { x := f(); }
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