From 3be794cdc2c7fc78a43b6a619ddf281b7271b520 Mon Sep 17 00:00:00 2001
From: =?utf8?q?R=C3=A9my=20Oudompheng?= <oudomphe@phare.normalesup.org>
Date: Fri, 14 Jun 2013 11:14:45 +0200
Subject: [PATCH] cmd/gc: instrument arrays properly in race detector.

The previous implementation would only record access to
the address of the array but the memory access to the whole
memory range must be recorded instead.

R=golang-dev, dvyukov, r
CC=golang-dev
https://golang.org/cl/8053044
---
 src/cmd/gc/builtin.c                      |  2 ++
 src/cmd/gc/racewalk.c                     | 37 +++++------------------
 src/cmd/gc/runtime.go                     |  2 ++
 src/pkg/runtime/race.c                    | 22 ++++++++++++++
 src/pkg/runtime/race/testdata/mop_test.go | 21 +++++++++++--
 5 files changed, 52 insertions(+), 32 deletions(-)

diff --git a/src/cmd/gc/builtin.c b/src/cmd/gc/builtin.c
index 9053dfe108..baa7d7845a 100644
--- a/src/cmd/gc/builtin.c
+++ b/src/cmd/gc/builtin.c
@@ -113,6 +113,8 @@ char *runtimeimport =
 	"func @\"\".racefuncexit ()\n"
 	"func @\"\".raceread (? uintptr)\n"
 	"func @\"\".racewrite (? uintptr)\n"
+	"func @\"\".racereadrange (@\"\".addr·1 uintptr, @\"\".size·2 uintptr)\n"
+	"func @\"\".racewriterange (@\"\".addr·1 uintptr, @\"\".size·2 uintptr)\n"
 	"\n"
 	"$$\n";
 char *unsafeimport =
diff --git a/src/cmd/gc/racewalk.c b/src/cmd/gc/racewalk.c
index 74d8522580..0c847d8bb8 100644
--- a/src/cmd/gc/racewalk.c
+++ b/src/cmd/gc/racewalk.c
@@ -439,8 +439,8 @@ static int
 callinstr(Node **np, NodeList **init, int wr, int skip)
 {
 	Node *f, *b, *n;
-	Type *t, *t1;
-	int class, res, hascalls;
+	Type *t;
+	int class, hascalls;
 
 	n = *np;
 	//print("callinstr for %+N [ %O ] etype=%E class=%d\n",
@@ -451,33 +451,6 @@ callinstr(Node **np, NodeList **init, int wr, int skip)
 	t = n->type;
 	if(isartificial(n))
 		return 0;
-	if(t->etype == TSTRUCT) {
-		// TODO: instrument arrays similarly.
-		// PARAMs w/o PHEAP are not interesting.
-		if(n->class == PPARAM || n->class == PPARAMOUT)
-			return 0;
-		res = 0;
-		hascalls = 0;
-		foreach(n, hascallspred, &hascalls);
-		if(hascalls) {
-			n = detachexpr(n, init);
-			*np = n;
-		}
-		for(t1=t->type; t1; t1=t1->down) {
-			if(t1->sym && strcmp(t1->sym->name, "_")) {
-				n = treecopy(n);
-				f = nod(OXDOT, n, newname(t1->sym));
-				f->type = t1;
-				if(f->type->etype == TFIELD)
-					f->type = f->type->type;
-				if(callinstr(&f, init, wr, 0)) {
-					typecheck(&f, Erv);
-					res = 1;
-				}
-			}
-		}
-		return res;
-	}
 
 	b = basenod(n);
 	// it skips e.g. stores to ... parameter array
@@ -498,7 +471,11 @@ callinstr(Node **np, NodeList **init, int wr, int skip)
 		}
 		n = treecopy(n);
 		makeaddable(n);
-		f = mkcall(wr ? "racewrite" : "raceread", T, init, uintptraddr(n));
+		if(t->etype == TSTRUCT || isfixedarray(t)) {
+			f = mkcall(wr ? "racewriterange" : "racereadrange", T, init, uintptraddr(n),
+					nodintconst(t->width));
+		} else
+			f = mkcall(wr ? "racewrite" : "raceread", T, init, uintptraddr(n));
 		*init = list(*init, f);
 		return 1;
 	}
diff --git a/src/cmd/gc/runtime.go b/src/cmd/gc/runtime.go
index 2139a95d93..d7032957b1 100644
--- a/src/cmd/gc/runtime.go
+++ b/src/cmd/gc/runtime.go
@@ -149,3 +149,5 @@ func racefuncenter(uintptr)
 func racefuncexit()
 func raceread(uintptr)
 func racewrite(uintptr)
+func racereadrange(addr, size uintptr)
+func racewriterange(addr, size uintptr)
diff --git a/src/pkg/runtime/race.c b/src/pkg/runtime/race.c
index 765a4b5502..557da6f8e3 100644
--- a/src/pkg/runtime/race.c
+++ b/src/pkg/runtime/race.c
@@ -77,6 +77,17 @@ runtime·racewrite(uintptr addr)
 	}
 }
 
+#pragma textflag 7
+void
+runtime·racewriterange(uintptr addr, uintptr sz)
+{
+	if(!onstack(addr)) {
+		m->racecall = true;
+		runtime∕race·WriteRange(g->racectx, (void*)addr, sz, runtime·getcallerpc(&addr));
+		m->racecall = false;
+	}
+}
+
 // Called from instrumented code.
 // If we split stack, getcallerpc() can return runtime·lessstack().
 #pragma textflag 7
@@ -90,6 +101,17 @@ runtime·raceread(uintptr addr)
 	}
 }
 
+#pragma textflag 7
+void
+runtime·racereadrange(uintptr addr, uintptr sz)
+{
+	if(!onstack(addr)) {
+		m->racecall = true;
+		runtime∕race·ReadRange(g->racectx, (void*)addr, sz, runtime·getcallerpc(&addr));
+		m->racecall = false;
+	}
+}
+
 // Called from runtime·racefuncenter (assembly).
 #pragma textflag 7
 void
diff --git a/src/pkg/runtime/race/testdata/mop_test.go b/src/pkg/runtime/race/testdata/mop_test.go
index 620b7ab6e4..9a0cb81f53 100644
--- a/src/pkg/runtime/race/testdata/mop_test.go
+++ b/src/pkg/runtime/race/testdata/mop_test.go
@@ -600,8 +600,7 @@ func TestRaceSprint(t *testing.T) {
 	<-ch
 }
 
-// Not implemented.
-func TestRaceFailingArrayCopy(t *testing.T) {
+func TestRaceArrayCopy(t *testing.T) {
 	ch := make(chan bool, 1)
 	var a [5]int
 	go func() {
@@ -612,6 +611,24 @@ func TestRaceFailingArrayCopy(t *testing.T) {
 	<-ch
 }
 
+// Blows up a naive compiler.
+func TestRaceNestedArrayCopy(t *testing.T) {
+	ch := make(chan bool, 1)
+	type (
+		Point32   [2][2][2][2][2]Point
+		Point1024 [2][2][2][2][2]Point32
+		Point32k  [2][2][2][2][2]Point1024
+		Point1M   [2][2][2][2][2]Point32k
+	)
+	var a, b Point1M
+	go func() {
+		a[0][1][0][1][0][1][0][1][0][1][0][1][0][1][0][1][0][1][0][1].y = 1
+		ch <- true
+	}()
+	a = b
+	<-ch
+}
+
 func TestRaceStructRW(t *testing.T) {
 	p := Point{0, 0}
 	ch := make(chan bool, 1)
-- 
2.48.1