PR c/90737 - [8/9/10 Regression] inconsistent address of a local converted to…

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: r271985

gcc/c/ChangeLog

 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.
+
+2019-06-05  Martin Sebor  <msebor@redhat.com>
+
 	* c-decl.c (start_decl): Adjust quoting and hyphenation
 	in diagnostics.
 	(finish_decl): Same.

gcc/c/c-typeck.c

@@ -10628,7 +10628,8 @@ 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,

gcc/cp/ChangeLog

+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.
+
 2019-06-05  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	* decl.c (smallest_type_location): New.

gcc/cp/typeck.c

@@ -9307,11 +9307,12 @@ 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);

gcc/testsuite/ChangeLog

+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.
+
 2019-06-05  Hongtao Liu  <hongtao.liu@intel.com>
 
 	* gcc.target/i386/avx512dq-vfpclasspd-1.c: Adjust scan assember

gcc/testsuite/c-c++-common/Wreturn-local-addr.c

+/* 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" } } */

gcc/testsuite/g++.dg/warn/Wreturn-local-addr-6.C

+/* 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" } } */