re PR middle-end/64242 (Longjmp expansion incorrect)

	PR middle-end/64242
	* builtins.c (expand_builtin_longjmp): Use a temporary when restoring
	the frame pointer.
	(expand_builtin_nonlocal_goto): Likewise.

	* gcc.c-torture/execute/pr64242.c: New test.

From-SVN: r266697

gcc/ChangeLog

+2018-11-30  Wilco Dijkstra  <wdijkstr@arm.com>
+
+	PR middle-end/64242
+	* builtins.c (expand_builtin_longjmp): Use a temporary when restoring
+	the frame pointer.
+	(expand_builtin_nonlocal_goto): Likewise.
+
 2018-11-30  David Malcolm  <dmalcolm@redhat.com>
 
 	* diagnostic-core.h (emit_diagnostic): New decl.

gcc/builtins.c

@@ -1143,8 +1143,11 @@ expand_builtin_longjmp (rtx buf_addr, rtx value)
 	  emit_clobber (gen_rtx_MEM (BLKmode, gen_rtx_SCRATCH (VOIDmode)));
 	  emit_clobber (gen_rtx_MEM (BLKmode, hard_frame_pointer_rtx));
 
-	  emit_move_insn (hard_frame_pointer_rtx, fp);
+	  /* Restore the frame pointer and stack pointer.  We must use a
+	     temporary since the setjmp buffer may be a local.  */
+	  fp = copy_to_reg (fp);
 	  emit_stack_restore (SAVE_NONLOCAL, stack);
+	  emit_move_insn (hard_frame_pointer_rtx, fp);
 
 	  emit_use (hard_frame_pointer_rtx);
 	  emit_use (stack_pointer_rtx);
@@ -1287,9 +1290,11 @@ expand_builtin_nonlocal_goto (tree exp)
       emit_clobber (gen_rtx_MEM (BLKmode, gen_rtx_SCRATCH (VOIDmode)));
       emit_clobber (gen_rtx_MEM (BLKmode, hard_frame_pointer_rtx));
 
-      /* Restore frame pointer for containing function.  */
-      emit_move_insn (hard_frame_pointer_rtx, r_fp);
+      /* Restore the frame pointer and stack pointer.  We must use a
+	 temporary since the setjmp buffer may be a local.  */
+      r_fp = copy_to_reg (r_fp);
       emit_stack_restore (SAVE_NONLOCAL, r_sp);
+      emit_move_insn (hard_frame_pointer_rtx, r_fp);
 
       /* USE of hard_frame_pointer_rtx added for consistency;
 	 not clear if really needed.  */

gcc/testsuite/ChangeLog

+2018-11-30  Wilco Dijkstra  <wdijkstr@arm.com>
+
+	PR middle-end/64242
+	* gcc.c-torture/execute/pr64242.c: New test.
+
 2018-11-30  David Malcolm  <dmalcolm@redhat.com>
 
 	* g++.dg/parse/missing-parens-fixit.C: New test.

gcc/testsuite/gcc.c-torture/execute/pr64242.c

+/* { dg-require-effective-target indirect_jumps } */
+
+extern void abort (void);
+
+__attribute ((noinline)) void
+broken_longjmp(void *p)
+{
+  void *buf[5];
+  __builtin_memcpy (buf, p, 5 * sizeof (void*));
+  /* Corrupts stack pointer...  */
+  __builtin_longjmp (buf, 1);
+}
+
+volatile int x = 0;
+volatile void *p;
+int
+main (void)
+{
+  void *buf[5];
+  p = __builtin_alloca (x);
+
+  if (!__builtin_setjmp (buf))
+    broken_longjmp (buf);
+
+  /* Fails if stack pointer corrupted.  */
+  if (p != __builtin_alloca (x))
+    abort();
+
+  return 0;
+}