cmd/vet: teach asmdecl check about NOFRAME

Change-Id: I3f71228e391f122f9cc5656ca6835fdf51a424b7
Reviewed-on: https://go-review.googlesource.com/92435
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

src/cmd/vet/asmdecl.go

@@ -240,17 +240,17 @@ Files:
 						continue
 					}
 				}
+				flag := m[3]
 				fn = knownFunc[fnName][arch]
 				if fn != nil {
 					size, _ := strconv.Atoi(m[5])
-					flag := m[3]
 					if size != fn.size && (flag != "7" && !strings.Contains(flag, "NOSPLIT") || size != 0) {
 						badf("wrong argument size %d; expected $...-%d", size, fn.size)
 					}
 				}
 				localSize, _ = strconv.Atoi(m[4])
 				localSize += archDef.intSize
-				if archDef.lr {
+				if archDef.lr && !strings.Contains(flag, "NOFRAME") {
 					// Account for caller's saved LR
 					localSize += archDef.intSize
 				}

src/cmd/vet/testdata/asm/asm.go

@@ -43,3 +43,6 @@ func wrapper(x int)
 
 func f15271() (x uint32)
 func f17584(x float32, y complex64)
+
+func noframe1(x int32)
+func noframe2(x int32)

src/cmd/vet/testdata/asm/asm3.s

@@ -176,3 +176,17 @@ TEXT ·leaf(SB),0,$-4-12
 	MOVW	y+4(FP), AX
 	MOVW	AX, ret+8(FP)
 	RET
+
+TEXT ·noframe1(SB),0,$0-4
+	MOVW	0(R13), AX // Okay; our saved LR
+	MOVW	4(R13), AX // Okay; caller's saved LR
+	MOVW	x+8(R13), AX // Okay; x argument
+	MOVW	12(R13), AX // ERROR "use of 12\(R13\) points beyond argument frame"
+	RET
+
+TEXT ·noframe2(SB),NOFRAME,$0-4
+	MOVW	0(R13), AX // Okay; caller's saved LR
+	MOVW	x+4(R13), AX // Okay; x argument
+	MOVW	8(R13), AX // ERROR "use of 8\(R13\) points beyond argument frame"
+	MOVW	12(R13), AX // ERROR "use of 12\(R13\) points beyond argument frame"
+	RET