Re: [PATCH] Fix -Wreturn-type with -fsanitize=return (PR c++/81212)

[Richard Biener <rguenther@suse.de>]

On December 2, 2017 1:14:10 AM GMT+01:00, Jakub Jelinek <jakub@redhat.com> wrote:
>Hi!
>
>With -fsanitize=return, we add __builtin_ubsan_handle_missing_return
>instead of __builtin_unreachable with BUILTINS_LOCATION locus,
>the following patch teaches warn function return pass to handle that
>too.
>
>Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

OK. 

Richard. 

>2017-12-01  Jakub Jelinek  <jakub@redhat.com>
>
>	PR c++/81212
>	* tree-cfg.c (pass_warn_function_return::execute): Handle
>	__builtin_ubsan_handle_missing_return like __builtin_unreachable
>	with BUILTINS_LOCATION.
>
>	* g++.dg/ubsan/pr81212.C: New test.
>	* g++.dg/ubsan/return-1.C: Add -Wno-return-type to dg-options.
>	* g++.dg/ubsan/return-2.C: Add -Wno-return-type to dg-options.
>	* g++.dg/ubsan/return-7.C: Add -Wno-return-type to dg-options.
>
>--- gcc/tree-cfg.c.jj	2017-12-01 09:10:12.000000000 +0100
>+++ gcc/tree-cfg.c	2017-12-01 19:38:21.933049446 +0100
>@@ -9151,10 +9151,13 @@ pass_warn_function_return::execute (func
> 	  if (EDGE_COUNT (bb->succs) == 0)
> 	    {
> 	      gimple *last = last_stmt (bb);
>+	      const enum built_in_function ubsan_missing_ret
>+		= BUILT_IN_UBSAN_HANDLE_MISSING_RETURN;
> 	      if (last
>-		  && (LOCATION_LOCUS (gimple_location (last))
>-		      == BUILTINS_LOCATION)
>-		  && gimple_call_builtin_p (last, BUILT_IN_UNREACHABLE))
>+		  && ((LOCATION_LOCUS (gimple_location (last))
>+		       == BUILTINS_LOCATION
>+		       && gimple_call_builtin_p (last, BUILT_IN_UNREACHABLE))
>+		      || gimple_call_builtin_p (last, ubsan_missing_ret)))
> 		{
> 		  gimple_stmt_iterator gsi = gsi_for_stmt (last);
> 		  gsi_prev_nondebug (&gsi);
>--- gcc/testsuite/g++.dg/ubsan/pr81212.C.jj	2017-12-01
>19:30:43.251747933 +0100
>+++ gcc/testsuite/g++.dg/ubsan/pr81212.C	2017-12-01 19:30:25.000000000
>+0100
>@@ -0,0 +1,16 @@
>+// PR c++/81212
>+// { dg-do compile }
>+// { dg-options "-Wreturn-type -fsanitize=return" }
>+
>+struct S
>+{
>+  S (void *);
>+  void *s;
>+};
>+
>+S
>+foo (bool x, void *y)
>+{
>+  if (x)
>+    return S (y);
>+}	// { dg-warning "control reaches end of non-void function" }
>--- gcc/testsuite/g++.dg/ubsan/return-1.C.jj	2013-11-22
>21:05:59.000000000 +0100
>+++ gcc/testsuite/g++.dg/ubsan/return-1.C	2017-12-01 22:23:17.053866660
>+0100
>@@ -1,5 +1,5 @@
> // { dg-do run }
>-// { dg-options "-fsanitize=return" }
>+// { dg-options "-fsanitize=return -Wno-return-type" }
> // { dg-shouldfail "ubsan" }
> 
> struct S { S (); ~S (); };
>--- gcc/testsuite/g++.dg/ubsan/return-2.C.jj	2014-10-22
>15:52:16.000000000 +0200
>+++ gcc/testsuite/g++.dg/ubsan/return-2.C	2017-12-01 22:23:32.059679081
>+0100
>@@ -1,5 +1,5 @@
> // { dg-do run }
>-// { dg-options "-fsanitize=return -fno-sanitize-recover=return" }
>+// { dg-options "-fsanitize=return -fno-sanitize-recover=return
>-Wno-return-type" }
> 
> struct S { S (); ~S (); };
> 
>--- gcc/testsuite/g++.dg/ubsan/return-7.C.jj	2016-11-23
>20:50:51.000000000 +0100
>+++ gcc/testsuite/g++.dg/ubsan/return-7.C	2017-12-01 22:24:03.894281135
>+0100
>@@ -1,5 +1,5 @@
> // { dg-do run }
>-// { dg-options "-fsanitize=undefined" }
>+// { dg-options "-fsanitize=undefined -Wno-return-type" }
> // { dg-shouldfail "ubsan" }
> 
> struct S { S (); ~S (); };
>
>	Jakub