cmd/compile: conditional on -race, disable inline of go:norace

Adds the appropriate check to inl.go.
Includes tests of both -race+go:norace and plain go:norace.

Fixes golang#24651.

Change-Id: Id806342430c20baf4679a985d12eea3b677092e0
Reviewed-on: https://go-review.googlesource.com/119195
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

src/cmd/compile/internal/gc/inl.go

@@ -132,6 +132,12 @@ func caninl(fn *Node) {
 		return
 	}
 
+	// If marked "go:norace" and -race compilation, don't inline.
+	if flag_race && fn.Func.Pragma&Norace != 0 {
+		reason = "marked go:norace with -race compilation"
+		return
+	}
+
 	// If marked "go:cgo_unsafe_args", don't inline, since the
 	// function makes assumptions about its argument frame layout.
 	if fn.Func.Pragma&CgoUnsafeArgs != 0 {

test/fixedbugs/issue24651a.go

@@ -0,0 +1,24 @@
+//errorcheck -0 -race -m -m
+
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+//go:norace
+func Foo(x int) int { // ERROR "cannot inline Foo: marked go:norace with -race compilation$"
+	return x * (x + 1) * (x + 2)
+}
+
+func Bar(x int) int { // ERROR "can inline Bar as: func\(int\) int { return x \* \(x \+ 1\) \* \(x \+ 2\) }$"
+	return x * (x + 1) * (x + 2)
+}
+
+var x = 5
+
+//go:noinline Provide a clean, constant reason for not inlining main
+func main() { // ERROR "cannot inline main: marked go:noinline$"
+	println("Foo(", x, ")=", Foo(x))
+	println("Bar(", x, ")=", Bar(x)) // ERROR "inlining call to Bar func\(int\) int { return x \* \(x \+ 1\) \* \(x \+ 2\) }$"
+}

test/fixedbugs/issue24651b.go

@@ -0,0 +1,24 @@
+//errorcheck -0 -m -m
+
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+//go:norace
+func Foo(x int) int { // ERROR "can inline Foo as: func\(int\) int { return x \* \(x \+ 1\) \* \(x \+ 2\) }$"
+	return x * (x + 1) * (x + 2)
+}
+
+func Bar(x int) int { // ERROR "can inline Bar as: func\(int\) int { return x \* \(x \+ 1\) \* \(x \+ 2\) }$"
+	return x * (x + 1) * (x + 2)
+}
+
+var x = 5
+
+//go:noinline Provide a clean, constant reason for not inlining main
+func main() { // ERROR "cannot inline main: marked go:noinline$"
+	println("Foo(", x, ")=", Foo(x)) // ERROR "inlining call to Foo func\(int\) int { return x \* \(x \+ 1\) \* \(x \+ 2\) }$"
+	println("Bar(", x, ")=", Bar(x)) // ERROR "inlining call to Bar func\(int\) int { return x \* \(x \+ 1\) \* \(x \+ 2\) }$"
+}