Re: [PATCH] Do not sanitize in lower_omp_target context (PR, sanitizer/78815).

[Martin Liška <mliska at suse dot cz>]

On 01/04/2017 10:31 AM, Jakub Jelinek wrote:
> On Wed, Jan 04, 2017 at 10:19:28AM +0100, Martin Liška wrote:
>> PING^1
>>
>> On 12/16/2016 01:04 PM, Martin Liška wrote:
>>> Currently, use-after-scope relies on fact that entry point of gimplify_decl_expr
>>> is gimplify_function_tree. Fixed by checking if asan_poisoned_variables is non-null.
>>>
>>> Patch can bootstrap on ppc64le-redhat-linux and survives regression tests.
>>>
>>> Ready to be installed?
> 
> Looking at asan_poisoned_variables, my preference would be to guard:
>   asan_poisoned_variables = new hash_set<tree> ();
> with
> if (asan_sanitize_use_after_scope ()
>     && !asan_no_sanitize_address_p ())
> the delete asan_poisoned_variables; with if (asan_poisoned_variables)
> and all the poisoning stuff in the gimplifier also with if
> (asan_poisoned_variables) and no need to repeat there the asan_sanitize_use_after_scope
> () and !asan_no_sanitize_address_p () tests.
>       if (asan_poisoned_variables != NULL
>           && asan_poisoned_variables->contains (t))
> is already fine,
>       if (asan_sanitize_use_after_scope ()
>           && !asan_no_sanitize_address_p ()
>           && !is_vla
>           && TREE_ADDRESSABLE (decl)
>           && !TREE_STATIC (decl)
>           && !DECL_HAS_VALUE_EXPR_P (decl)
>           && dbg_cnt (asan_use_after_scope))
> should replace the first 2 conditions with asan_poisoned_variables,
>           if (asan_sanitize_use_after_scope ()
>               && asan_used_labels != NULL
>               && asan_used_labels->contains (label))
>             asan_poison_variables (asan_poisoned_variables, false, pre_p);
> should replace asan_sanitize_use_after_scope () with
> asan_poisoned_variables.  IMHO no need to add comments, especially not one
> mentioning omp lowering - the gimplifier is called from lots of various
> places.
> 
> 	Jakub
> 

I like your approach, I'm sending updated patch which bootstraps and survives
regression tests.

Ready to be installed?
Martin

>From 42887cf5fe7d94709ee5356fb6534c7a4fc26bff Mon Sep 17 00:00:00 2001
From: marxin <mliska@suse.cz>
Date: Wed, 4 Jan 2017 16:43:49 +0100
Subject: [PATCH] Do not sanitize in an abnormal context (PR sanitizer/78815).

gcc/ChangeLog:

2017-01-04  Martin Liska  <mliska@suse.cz>

	PR sanitizer/78815
	* gimplify.c (gimplify_decl_expr): Compare to
	asan_poisoned_variables instread of checking flags.
	(gimplify_target_expr): Likewise.
	(gimplify_expr): Likewise.
	(gimplify_function_tree): Conditionally initialize
	asan_poisoned_variables.
---
 gcc/gimplify.c | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/gcc/gimplify.c b/gcc/gimplify.c
index 14e79b4b3f3..e1e9ce9e903 100644
--- a/gcc/gimplify.c
+++ b/gcc/gimplify.c
@@ -1620,8 +1620,7 @@ gimplify_decl_expr (tree *stmt_p, gimple_seq *seq_p)
 	  is_vla = true;
 	}
 
-      if (asan_sanitize_use_after_scope ()
-	  && !asan_no_sanitize_address_p ()
+      if (asan_poisoned_variables
 	  && !is_vla
 	  && TREE_ADDRESSABLE (decl)
 	  && !TREE_STATIC (decl)
@@ -6413,8 +6412,7 @@ gimplify_target_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p)
 	      else
 		cleanup = clobber;
 	    }
-	  if (asan_sanitize_use_after_scope ()
-	      && dbg_cnt (asan_use_after_scope))
+	  if (asan_poisoned_variables && dbg_cnt (asan_use_after_scope))
 	    {
 	      tree asan_cleanup = build_asan_poison_call_expr (temp);
 	      if (asan_cleanup)
@@ -11426,7 +11424,7 @@ gimplify_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p,
 	  /* If the label is used in a goto statement, or address of the label
 	     is taken, we need to unpoison all variables that were seen so far.
 	     Doing so would prevent us from reporting a false positives.  */
-	  if (asan_sanitize_use_after_scope ()
+	  if (asan_poisoned_variables
 	      && asan_used_labels != NULL
 	      && asan_used_labels->contains (label))
 	    asan_poison_variables (asan_poisoned_variables, false, pre_p);
@@ -12531,10 +12529,14 @@ gimplify_function_tree (tree fndecl)
       && !needs_to_live_in_memory (ret))
     DECL_GIMPLE_REG_P (ret) = 1;
 
-  asan_poisoned_variables = new hash_set<tree> ();
+  if (asan_sanitize_use_after_scope () && !asan_no_sanitize_address_p ())
+    asan_poisoned_variables = new hash_set<tree> ();
   bind = gimplify_body (fndecl, true);
-  delete asan_poisoned_variables;
-  asan_poisoned_variables = NULL;
+  if (asan_poisoned_variables)
+    {
+      delete asan_poisoned_variables;
+      asan_poisoned_variables = NULL;
+    }
 
   /* The tree body of the function is no longer needed, replace it
      with the new GIMPLE body.  */
-- 
2.11.0