backport: PR c/90737 - [8/9/10 Regression] inconsistent address of a local converted...

Backport from mainline

PR c/90737 - [8/9/10 Regression] inconsistent address of a local converted to intptr_t between callee and caller

gcc/c/ChangeLog:

	PR c/90737
	* c-typeck.c (c_finish_return): Only consider functions returning
	pointers as candidates for -Wreturn-local-addr.

gcc/cp/ChangeLog:

	PR c/90737
	* typeck.c (maybe_warn_about_returning_address_of_local): Only
	consider functions returning pointers as candidates for
	-Wreturn-local-addr.

gcc/testsuite/ChangeLog:

	PR c/90737
	* c-c++-common/Wreturn-local-addr.c: New test.
	* g++.dg/warn/Wreturn-local-addr-6.C: New test.

From-SVN: r274022

diff --git a/gcc/c/ChangeLog b/gcc/c/ChangeLog
index 9455a8f68e103e0d86a0843f24145197f7f6409f..d635177740111843fae08442a2d3da6da63db27b 100644 (file)
--- a/gcc/c/ChangeLog
+++ b/gcc/c/ChangeLog
@@ -1,3 +1,12 @@
+2019-08-02  Martin Sebor  <msebor@redhat.com>
+
+       Backport from mainline
+       2019-06-05  Martin Sebor  <msebor@redhat.com>
+
+       PR c/90737
+       * c-typeck.c (c_finish_return): Only consider functions returning
+       pointers as candidates for -Wreturn-local-addr.
+
 2019-08-01  Jakub Jelinek  <jakub@redhat.com>
 
        Backported from mainline

diff --git a/gcc/c/c-typeck.c b/gcc/c/c-typeck.c
index 4e4437540028ee53110aeeb89c6f8c5812097687..4a4eb08b73f94984d036a2792647fec67f641fcd 100644 (file)
--- a/gcc/c/c-typeck.c
+++ b/gcc/c/c-typeck.c
@@ -10627,7 +10627,8 @@ c_finish_return (location_t loc, tree retval, tree origtype)
              if (DECL_P (inner)
                  && !DECL_EXTERNAL (inner)
                  && !TREE_STATIC (inner)
-                 && DECL_CONTEXT (inner) == current_function_decl)
+                 && DECL_CONTEXT (inner) == current_function_decl
+                 && POINTER_TYPE_P (TREE_TYPE (TREE_TYPE (current_function_decl))))
                {
                  if (TREE_CODE (inner) == LABEL_DECL)
                    warning_at (loc, OPT_Wreturn_local_addr,

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 4f04385b59062f5a80ed4f2d8e97f95eb317bc0d..af1dfe322b7d86d7d3e5a82fc7dfc543e1c2ff38 100644 (file)
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,13 @@
+2019-08-02  Martin Sebor  <msebor@redhat.com>
+
+       Backport from mainline
+       2019-06-05  Martin Sebor  <msebor@redhat.com>
+
+       PR c/90737
+       * typeck.c (maybe_warn_about_returning_address_of_local): Only
+       consider functions returning pointers as candidates for
+       -Wreturn-local-addr.
+
 2019-08-02  Marek Polacek  <polacek@redhat.com>
 
        Backported from mainline

diff --git a/gcc/cp/typeck.c b/gcc/cp/typeck.c
index 71daf32733a302a674f03a0f6647e8033cdbbb0c..3255af58a25eacfedb260102e68682e05e31ace7 100644 (file)
--- a/gcc/cp/typeck.c
+++ b/gcc/cp/typeck.c
@@ -9311,11 +9311,12 @@ maybe_warn_about_returning_address_of_local (tree retval)
                        "returning local initializer_list variable %qD "
                        "does not extend the lifetime of the underlying array",
                        whats_returned);
-      else if (TREE_CODE (whats_returned) == LABEL_DECL)
+      else if (POINTER_TYPE_P (valtype)
+              && TREE_CODE (whats_returned) == LABEL_DECL)
        w = warning_at (loc, OPT_Wreturn_local_addr,
                        "address of label %qD returned",
                        whats_returned);
-      else
+      else if (POINTER_TYPE_P (valtype))
        w = warning_at (loc, OPT_Wreturn_local_addr,
                        "address of local variable %qD returned",
                        whats_returned);

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index ec03b2ca47cde6ae3e141983b86791ccda20ef30..4371fc7226805847cdc99af6f3abb5af70cfe323 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,12 @@
+2019-08-02  Martin Sebor  <msebor@redhat.com>
+
+       Backport from mainline
+       2019-06-05  Martin Sebor  <msebor@redhat.com>
+
+       PR c/90737
+       * c-c++-common/Wreturn-local-addr.c: New test.
+       * g++.dg/warn/Wreturn-local-addr-6.C: New test.
+
 2019-08-02  Martin Sebor  <msebor@redhat.com>
 
        Backport from mainline

diff --git a/gcc/testsuite/c-c++-common/Wreturn-local-addr.c b/gcc/testsuite/c-c++-common/Wreturn-local-addr.c
new file mode 100644 (file)
index 0000000..c8c3b90
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/Wreturn-local-addr.c
@@ -0,0 +1,47 @@
+/* PR c/90737 - inconsistent address of a local converted to intptr_t
+   between callee and caller
+   { dg-do compile }
+   { dg-options "-O1 -Wall -Wreturn-local-addr -fdump-tree-optimized" } */
+
+typedef __INTPTR_TYPE__ intptr_t;
+
+static inline intptr_t
+return_addr_local_as_int (void)
+{
+  int i;
+  if ((intptr_t)&i == 0)
+    __builtin_abort ();
+
+  return (intptr_t)&i;
+}
+
+void get_addr_local_as_int (void)
+{
+  intptr_t i = return_addr_local_as_int ();
+  if (i == 0)
+    __builtin_abort ();
+}
+
+
+static inline intptr_t
+return_addr_label_as_int (void)
+{
+ label:
+  if ((intptr_t)&&label == 0)
+    __builtin_abort ();
+
+  return (intptr_t)&&label;
+}
+
+void get_addr_label_as_int (void)
+{
+  intptr_t i = return_addr_label_as_int ();
+  if (i == 0)
+    __builtin_abort ();
+}
+
+/* Verify that the functions that return the address of the label
+   or local variable have been optimized away and so have the calls
+   to abort.
+  { dg-final { scan-tree-dump-not "return_addr_" "optimized" } }
+  { dg-final { scan-tree-dump-not "abort" "optimized" } } */

diff --git a/gcc/testsuite/g++.dg/warn/Wreturn-local-addr-6.C b/gcc/testsuite/g++.dg/warn/Wreturn-local-addr-6.C
new file mode 100644 (file)
index 0000000..bfe1445
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/Wreturn-local-addr-6.C
@@ -0,0 +1,29 @@
+/* PR c/90737 - inconsistent address of a local converted to intptr_t
+   between callee and caller
+   { dg-do compile }
+   { dg-options "-O1 -Wall -Wreturn-local-addr -fdump-tree-optimized" } */
+
+typedef __INTPTR_TYPE__ intptr_t;
+
+const intptr_t&
+return_addr_label_as_intref (void)
+{
+ label:
+  if ((const intptr_t*)&&label == 0)
+    __builtin_exit (1);
+
+  return *(const intptr_t*)&&label;   // { dg-warning "\\\[-Wreturn-local-addr]" } */
+}
+
+const intptr_t&
+return_addr_local_as_intref (void)
+{
+  int a[1];
+  if ((const intptr_t*)a == 0)
+    __builtin_exit (1);
+
+  return (const intptr_t&)a;   // { dg-warning "\\\[-Wreturn-local-addr]" } */
+}
+
+/* Verify that the return value has been replaced with zero:
+  { dg-final { scan-tree-dump-times "return 0;" 2 "optimized" } } */