feat(lint): abi0 register-args rule and go-asm width model

2026-08-29 13:36:28 +02:00
parent 6699ebd34f
commit d75e6bcae6
5 changed files with 244 additions and 21 deletions
@@ -335,3 +335,79 @@ TEXT ·f(SB), NOSPLIT, $0
 		t.Fatalf("correct width must not be flagged: %+v", diags)
 	}
 }
+
+func TestABI0RegisterArgs(t *testing.T) {
+	// A kernel with a // func signature whose parameters are never read from
+	// the FP frame: the classic register-args port bug.
+	diags := lintSrc(t, `
+// func kernel(text *byte, n int)
+TEXT ·kernel(SB), NOSPLIT, $0-16
+	MOVQ DI, R10
+	MOVQ R9, AX
+	RET
+`)
+	if codes(diags)[CodeABI0RegisterArgs] != 1 {
+		t.Fatalf("want one abi0-register-args, got %+v", diags)
+	}
+
+	// Reading every parameter from the frame is correct.
+	diags = lintSrc(t, `
+// func kernel(text *byte, n int)
+TEXT ·kernel(SB), NOSPLIT, $0-16
+	MOVQ text+0(FP), AX
+	MOVQ n+8(FP), BX
+	RET
+`)
+	if codes(diags)[CodeABI0RegisterArgs] != 0 {
+		t.Fatalf("frame-reading kernel must not be flagged: %+v", diags)
+	}
+
+	// Only a result write to FP, no parameter read: still flagged.
+	diags = lintSrc(t, `
+// func top(sa []int32) int
+TEXT ·top(SB), NOSPLIT, $0-24
+	MOVQ SI, R10
+	MOVQ R10, ret+16(FP)
+	RET
+`)
+	if codes(diags)[CodeABI0RegisterArgs] != 1 {
+		t.Fatalf("result-only FP write must still be flagged: %+v", diags)
+	}
+
+	// No signature: stay silent.
+	diags = lintSrc(t, `
+TEXT ·bare(SB), NOSPLIT, $0-16
+	MOVQ DI, AX
+	RET
+`)
+	if codes(diags)[CodeABI0RegisterArgs] != 0 {
+		t.Fatalf("signature-less function must not be flagged: %+v", diags)
+	}
+}
+
+func TestRegisterWidthCanonicalNames(t *testing.T) {
+	// Canonical Go asm names with an L operation: the correct spelling for a
+	// 32-bit operation, never a width mismatch.
+	diags := lintSrc(t, `
+#include "textflag.h"
+TEXT ·f(SB), NOSPLIT, $0
+	MOVL (BX)(R9*4), SI
+	XORL R9, R9
+	MOVL 128(BX)(R9*4), R12
+	RET
+`)
+	if codes(diags)[CodeRegisterWidthMismatch] != 0 {
+		t.Fatalf("canonical 64-bit names with L ops must not be flagged: %+v", diags)
+	}
+
+	// A byte register in an L operation stays a mismatch.
+	diags = lintSrc(t, `
+#include "textflag.h"
+TEXT ·f(SB), NOSPLIT, $0
+	MOVL AL, DX
+	RET
+`)
+	if codes(diags)[CodeRegisterWidthMismatch] != 1 {
+		t.Fatalf("byte register in L op must be flagged: %+v", diags)
+	}
+}