diff mbox

libgo patch committed: Don't assume that _ = *s will panic if s is nil

Message ID CAOyqgcVnO9jmhQkifLVFSX7_R88wGagdK_6TJgOOXM5PvPGWtQ@mail.gmail.com
State New
Headers show

Commit Message

Ian Lance Taylor June 22, 2017, 2:46 p.m. UTC 
With the gc toolchain apparently
    var s *string
    _ = *s
is enough to panic with a nil pointer dereference. The gccgo compiler
will simply discard the dereference, which I think is a reasonable and
acceptable optimization. Change the tests to use an exported variable
instead. The tests are not currently run, but they will be with a
later patch to gotools.

Bootstrapped and ran Go testsuite on x86_64-pc-linux-gnu.  Committed
to mainline.

Ian
diff mbox

Patch

Index: gcc/go/gofrontend/MERGE
===================================================================
--- gcc/go/gofrontend/MERGE	(revision 249561)
+++ gcc/go/gofrontend/MERGE	(working copy)
@@ -1,4 +1,4 @@ 
-b5c9fe259ec43f8079581c3bea0f1d12d85213a7
+8804c912363320e0c229c5a471fb6f4b9e5965e6
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.
Index: libgo/go/runtime/testdata/testprog/crash.go
===================================================================
--- libgo/go/runtime/testdata/testprog/crash.go	(revision 249205)
+++ libgo/go/runtime/testdata/testprog/crash.go	(working copy)
@@ -13,6 +13,8 @@  func init() {
 	register("Crash", Crash)
 }
 
+var NilPointer *string
+
 func test(name string) {
 	defer func() {
 		if x := recover(); x != nil {
@@ -21,8 +23,7 @@  func test(name string) {
 		fmt.Printf(" done\n")
 	}()
 	fmt.Printf("%s:", name)
-	var s *string
-	_ = *s
+	*NilPointer = name
 	fmt.Print("SHOULD NOT BE HERE")
 }
 
Index: libgo/go/runtime/testdata/testprogcgo/crash.go
===================================================================
--- libgo/go/runtime/testdata/testprogcgo/crash.go	(revision 249205)
+++ libgo/go/runtime/testdata/testprogcgo/crash.go	(working copy)
@@ -13,6 +13,8 @@  func init() {
 	register("Crash", Crash)
 }
 
+var NilPointer *string
+
 func test(name string) {
 	defer func() {
 		if x := recover(); x != nil {
@@ -21,8 +23,7 @@  func test(name string) {
 		fmt.Printf(" done\n")
 	}()
 	fmt.Printf("%s:", name)
-	var s *string
-	_ = *s
+	*NilPointer = name
 	fmt.Print("SHOULD NOT BE HERE")
 }