cmd/compile: generalize racewalk to instrument (naming change)

This is mechanical change that is a step toward reusing the racewalk
pass for a more general instrumentation pass.  The first use will be to
add support for the memory sanitizer.

Change-Id: I75b93b814ac60c1db1660e0b9a9a7d7977d86939
Reviewed-on: https://go-review.googlesource.com/16105
Reviewed-by: Hyang-Ah Hana Kim <[email protected]>
Reviewed-by: David Crawshaw <[email protected]>

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

@@ -647,6 +647,10 @@ var flag_race int
 
 var flag_largemodel int
 
+// Whether we are adding any sort of code instrumentation, such as
+// when the race detector is enabled.
+var instrumenting bool
+
 // Pending annotations for next func declaration.
 var (
 	noescape       bool

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

@@ -124,13 +124,13 @@ func caninl(fn *Node) {
 		}
 	}
 
-	// Runtime package must not be race instrumented.
-	// Racewalk skips runtime package. However, some runtime code can be
+	// Runtime package must not be instrumented.
+	// Instrument skips runtime package. However, some runtime code can be
 	// inlined into other packages and instrumented there. To avoid this,
-	// we disable inlining of runtime functions in race mode.
+	// we disable inlining of runtime functions when instrumenting.
 	// The example that we observed is inlining of LockOSThread,
 	// which lead to false race reports on m contents.
-	if flag_race != 0 && myimportpath == "runtime" {
+	if instrumenting && myimportpath == "runtime" {
 		return
 	}
 

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

@@ -249,6 +249,7 @@ func Main() {
 	if flag_race != 0 {
 		racepkg = mkpkg("runtime/race")
 		racepkg.Name = "race"
+		instrumenting = true
 	}
 
 	// parse -d argument

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

@@ -434,7 +434,7 @@ func ordermapassign(n *Node, order *Order) {
 				a = Nod(OAS, m, l.N)
 				typecheck(&a, Etop)
 				post = list(post, a)
-			} else if flag_race != 0 && n.Op == OAS2FUNC && !isblank(l.N) {
+			} else if instrumenting && n.Op == OAS2FUNC && !isblank(l.N) {
 				m = l.N
 				l.N = ordertemp(m.Type, order, false)
 				a = Nod(OAS, m, l.N)
@@ -1093,7 +1093,7 @@ func orderexpr(np **Node, order *Order, lhs *Node) {
 		OREAL,
 		ORECOVER:
 		ordercall(n, order)
-		if lhs == nil || lhs.Op != ONAME || flag_race != 0 {
+		if lhs == nil || lhs.Op != ONAME || instrumenting {
 			n = ordercopyexpr(n, n.Type, order, 0)
 		}
 
@@ -1153,7 +1153,7 @@ func orderexpr(np **Node, order *Order, lhs *Node) {
 		// TODO(rsc): The Isfat is for consistency with componentgen and walkexpr.
 		// It needs to be removed in all three places.
 		// That would allow inlining x.(struct{*int}) the same as x.(*int).
-		if !isdirectiface(n.Type) || Isfat(n.Type) || flag_race != 0 {
+		if !isdirectiface(n.Type) || Isfat(n.Type) || instrumenting {
 			n = ordercopyexpr(n, n.Type, order, 1)
 		}
 

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

@@ -399,8 +399,8 @@ func compile(fn *Node) {
 	if nerrors != 0 {
 		goto ret
 	}
-	if flag_race != 0 {
-		racewalk(Curfn)
+	if instrumenting {
+		instrument(Curfn)
 	}
 	if nerrors != 0 {
 		goto ret