Patchwork [RFC] Implement Undefined Behavior Sanitizer (take 2)

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Submitter Marek Polacek
Date June 12, 2013, 3:17 p.m.
Message ID <20130612151745.GA20883@redhat.com>
Download mbox | patch
Permalink /patch/250810/
State New
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Comments

Marek Polacek - June 12, 2013, 3:17 p.m.
On Wed, Jun 12, 2013 at 03:52:08PM +0200, Jakub Jelinek wrote:
> No, you really need to use the cp_save_expr/c_save_expr, especially for
> C it e.g. fully folds etc.  You want to call that in
> cp_build_binary_op etc., also because you want both the instrument_expr
> itself, but also the original binary expression to use the SAVE_EXPRs if
> they are created.

I see.  Here's somewhat tweaked version; it uses
c_save_expr/cp_save_expr + contains a few fixes suggested by Marc.
How does it look now?  Jason, does the cp/typeck.c part look sane?
Thanks.

2013-06-12  Marek Polacek  <polacek@redhat.com>

	* Makefile.in: Add ubsan.c.
	* common.opt: Add -fsanitize=undefined option.
	* doc/invoke.texi: Document the new flag.
	* sanitizer.def (DEF_SANITIZER_BUILTIN): Define.
	* builtin-attrs.def (ATTR_COLD): Define.
	* asan.c (initialize_sanitizer_builtins): Build
	BT_FN_VOID_PTR_PTR_PTR.
	* builtins.def (BUILT_IN_UBSAN_HANDLE_DIVREM_OVERFLOW,
	BUILT_IN_UBSAN_HANDLE_SHIFT_OUT_OF_BOUNDS): Define.

c-family/
	* c-ubsan.c: New file.
	* c-ubsan.h: New file.

cp/
	* typeck.c (cp_build_binary_op): Add division by zero and shift
	instrumentation.

c/
	* c-typeck.c (build_binary_op): Add division by zero and shift
	instrumentation.



	Marek
Jakub Jelinek - June 12, 2013, 3:29 p.m.
On Wed, Jun 12, 2013 at 05:17:45PM +0200, Marek Polacek wrote:
> @@ -3867,6 +3868,7 @@ cp_build_binary_op (location_t location,
>    tree final_type = 0;
>  
>    tree result;
> +  tree orig_type = NULL;
>  
>    /* Nonzero if this is an operation like MIN or MAX which can
>       safely be computed in short if both args are promoted shorts.
> @@ -3891,6 +3893,15 @@ cp_build_binary_op (location_t location,
>    op0 = orig_op0;
>    op1 = orig_op1;
>  
> +  /* Remember whether we're doing / or %.  */
> +  bool doing_div_or_mod = false;
> +
> +  /* Remember whether we're doing << or >>.  */
> +  bool doing_shift = false;
> +
> +  /* Tree holding instrumentation expression.  */
> +  tree instrument_expr = NULL;
> +
>    if (code == TRUTH_AND_EXPR || code == TRUTH_ANDIF_EXPR
>        || code == TRUTH_OR_EXPR || code == TRUTH_ORIF_EXPR
>        || code == TRUTH_XOR_EXPR)
> @@ -4070,8 +4081,12 @@ cp_build_binary_op (location_t location,
>  	{
>  	  enum tree_code tcode0 = code0, tcode1 = code1;
>  	  tree cop1 = fold_non_dependent_expr_sfinae (op1, tf_none);
> +	  cop1 = maybe_constant_value (cop1);
>  
> -	  warn_for_div_by_zero (location, maybe_constant_value (cop1));
> +	  if (!processing_template_decl && tcode0 == INTEGER_TYPE)
> +	    doing_div_or_mod = true;

Either the !processing_template_decl here is unneeded, or
if you'd check it (and perhaps flag_ubsan too) in this part of code,
then you wouldn't need to check it later.

> @@ -4832,6 +4853,31 @@ cp_build_binary_op (location_t location,
>    if (build_type == NULL_TREE)
>      build_type = result_type;
>  
> +  if (flag_ubsan && !processing_template_decl)

But, I'd certainly avoid doing the cp_save_expr/maybe_constant_value
etc. for all the binary operations you don't want to instrument
(thus check (doing_div_or_mod || doing_shift) also).
- 
> +    {
> +      /* OP0 and/or OP1 might have side-effects.  */
> +      op0 = cp_save_expr (op0);
> +      op1 = cp_save_expr (op1);
> +      op0 = maybe_constant_value (fold_non_dependent_expr_sfinae (op0,
> +								  tf_none));
> +      op1 = maybe_constant_value (fold_non_dependent_expr_sfinae (op1,
> +								  tf_none));
> +      if (doing_div_or_mod)
> +	{
> +	  /* For diagnostics we want to use the promoted types without
> +	     shorten_binary_op.  So convert the arguments to the
> +	     original result_type.  */
> +	  if (orig_type != NULL && result_type != orig_type)
> +	    {
> +	      op0 = cp_convert (orig_type, op0, complain);
> +	      op1 = cp_convert (orig_type, op1, complain);

And you don't want to change op0/op1, have your own tree vars, assign
op{0,1} to them and change here if result_type is not orig_type,
then pass those vars to ubsan_instrument_division.

	Jakub

Patch

--- gcc/c-family/c-ubsan.c.mp	2013-06-11 19:51:55.555492466 +0200
+++ gcc/c-family/c-ubsan.c	2013-06-12 17:05:20.800370083 +0200
@@ -0,0 +1,127 @@ 
+/* UndefinedBehaviorSanitizer, undefined behavior detector.
+   Copyright (C) 2013 Free Software Foundation, Inc.
+   Contributed by Marek Polacek <polacek@redhat.com>
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "tree.h"
+#include "c-family/c-common.h"
+#include "c-family/c-ubsan.h"
+
+/* Instrument division by zero and INT_MIN / -1.  If not instrumenting,
+   return NULL_TREE.  */
+
+tree
+ubsan_instrument_division (location_t loc, tree op0, tree op1)
+{
+  tree t, tt;
+  tree type = TREE_TYPE (op0);
+
+  /* At this point both operands should have the same type,
+     because they are already converted to RESULT_TYPE.  */
+  gcc_assert (type == TREE_TYPE (op1));
+
+  if (TREE_CODE (type) != INTEGER_TYPE)
+    return NULL_TREE;
+
+  /* If we *know* that the divisor is not -1 or 0, we don't have to
+     instrument this expression.
+     ??? We could use decl_constant_value to cover up more cases.  */
+  if (TREE_CODE (op1) == INTEGER_CST
+      && integer_nonzerop (op1)
+      && !integer_minus_onep (op1))
+    return NULL_TREE;
+
+  t = fold_build2 (EQ_EXPR, boolean_type_node,
+		    op1, build_int_cst (type, 0));
+
+  /* We check INT_MIN / -1 only for signed types.  */
+  if (!TYPE_UNSIGNED (type))
+    {
+      tree x;
+      tt = fold_build2 (EQ_EXPR, boolean_type_node, op1,
+			build_int_cst (type, -1));
+      x = fold_build2 (EQ_EXPR, boolean_type_node, op0,
+		       TYPE_MIN_VALUE (type));
+      x = fold_build2 (TRUTH_AND_EXPR, boolean_type_node, x, tt);
+      t = fold_build2 (TRUTH_OR_EXPR, boolean_type_node, t, x);
+    }
+  tt = builtin_decl_explicit (BUILT_IN_UBSAN_HANDLE_DIVREM_OVERFLOW);
+  tt = build_call_expr_loc (loc, tt, 0);
+  t = fold_build3 (COND_EXPR, void_type_node, t, tt, void_zero_node);
+
+  return t;
+}
+
+/* Instrument left and right shifts.  If not instrumenting, return
+   NULL_TREE.  */
+
+tree
+ubsan_instrument_shift (location_t loc, enum tree_code code,
+			tree op0, tree op1)
+{
+  tree t, tt = NULL_TREE;
+  tree op1_utype = unsigned_type_for (TREE_TYPE (op1));
+  HOST_WIDE_INT op0_prec = TYPE_PRECISION (TREE_TYPE (op0));
+  tree uprecm1 = build_int_cst (op1_utype, op0_prec - 1);
+  tree precm1 = build_int_cst (TREE_TYPE (op1), op0_prec - 1);
+
+  t = fold_convert_loc (loc, op1_utype, op1);
+  t = fold_build2 (GT_EXPR, boolean_type_node, t, uprecm1);
+
+  /* For signed x << y, in C99/C11, the following:
+     (unsigned) x >> (precm1 - y)
+     if non-zero, is undefined.  */
+  if (code == LSHIFT_EXPR
+      && !TYPE_UNSIGNED (TREE_TYPE (op0))
+      && flag_isoc99)
+    {
+      tree x = fold_build2 (MINUS_EXPR, integer_type_node, precm1, op1);
+      tt = fold_convert_loc (loc, unsigned_type_for (TREE_TYPE (op0)), op0);
+      tt = fold_build2 (RSHIFT_EXPR, TREE_TYPE (tt), tt, x);
+      tt = fold_build2 (NE_EXPR, boolean_type_node, tt,
+			build_int_cst (TREE_TYPE (tt), 0));
+    }
+
+  /* For signed x << y, in C++11/C++14, the following:
+     x < 0 || ((unsigned) x >> (precm1 - y))
+     if > 1, is undefined.  */
+  if (code == LSHIFT_EXPR
+      && !TYPE_UNSIGNED (TREE_TYPE (op0))
+      && (cxx_dialect == cxx11 || cxx_dialect == cxx1y))
+    {
+      tree x = fold_build2 (MINUS_EXPR, integer_type_node, precm1, op1);
+      tt = fold_convert_loc (loc, unsigned_type_for (TREE_TYPE (op0)), op0);
+      tt = fold_build2 (RSHIFT_EXPR, TREE_TYPE (tt), tt, x);
+      tt = fold_build2 (GT_EXPR, boolean_type_node, tt,
+			build_int_cst (TREE_TYPE (tt), 1));
+      x = fold_build2 (LT_EXPR, boolean_type_node, op0,
+		       build_int_cst (TREE_TYPE (op0), 0));
+      tt = fold_build2 (TRUTH_OR_EXPR, boolean_type_node, x, tt);
+    }
+
+  t = fold_build2 (TRUTH_OR_EXPR, boolean_type_node, t,
+		   tt ? tt : integer_zero_node);
+  tt = builtin_decl_explicit (BUILT_IN_UBSAN_HANDLE_SHIFT_OUT_OF_BOUNDS);
+  tt = build_call_expr_loc (loc, tt, 0);
+  t = fold_build3 (COND_EXPR, void_type_node, t, tt, void_zero_node);
+
+  return t;
+}
--- gcc/c-family/c-ubsan.h.mp	2013-06-11 19:51:50.616457500 +0200
+++ gcc/c-family/c-ubsan.h	2013-06-11 16:51:38.297942275 +0200
@@ -0,0 +1,27 @@ 
+/* UndefinedBehaviorSanitizer, undefined behavior detector.
+   Copyright (C) 2013 Free Software Foundation, Inc.
+   Contributed by Marek Polacek <polacek@redhat.com>
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
+#ifndef GCC_UBSAN_H
+#define GCC_UBSAN_H
+
+extern tree ubsan_instrument_division (location_t, tree, tree);
+extern tree ubsan_instrument_shift (location_t, enum tree_code, tree, tree);
+
+#endif  /* GCC_UBSAN_H  */
--- gcc/sanitizer.def.mp	2013-06-11 19:51:43.781408808 +0200
+++ gcc/sanitizer.def	2013-06-11 19:53:37.768224970 +0200
@@ -283,3 +283,13 @@  DEF_SANITIZER_BUILTIN(BUILT_IN_TSAN_ATOM
 DEF_SANITIZER_BUILTIN(BUILT_IN_TSAN_ATOMIC_SIGNAL_FENCE,
 		      "__tsan_atomic_signal_fence",
 		      BT_FN_VOID_INT, ATTR_NOTHROW_LEAF_LIST)
+
+/* Undefined Behavior Sanitizer */
+DEF_SANITIZER_BUILTIN(BUILT_IN_UBSAN_HANDLE_DIVREM_OVERFLOW,
+		      "__ubsan_handle_divrem_overflow",
+		      BT_FN_VOID_PTR_PTR_PTR,
+		      ATTR_COLD_NORETURN_NOTHROW_LEAF_LIST)
+DEF_SANITIZER_BUILTIN(BUILT_IN_UBSAN_HANDLE_SHIFT_OUT_OF_BOUNDS,
+		      "__ubsan_handle_shift_out_of_bounds",
+		      BT_FN_VOID_PTR_PTR_PTR,
+		      ATTR_COLD_NORETURN_NOTHROW_LEAF_LIST)
--- gcc/builtins.def.mp	2013-06-11 19:51:43.790408877 +0200
+++ gcc/builtins.def	2013-06-11 19:53:37.721224606 +0200
@@ -155,7 +155,7 @@  along with GCC; see the file COPYING3.
 #define DEF_SANITIZER_BUILTIN(ENUM, NAME, TYPE, ATTRS) \
   DEF_BUILTIN (ENUM, "__builtin_" NAME, BUILT_IN_NORMAL, TYPE, TYPE,    \
 	       true, true, true, ATTRS, true, \
-	       (flag_asan || flag_tsan))
+	       (flag_asan || flag_tsan || flag_ubsan))
 
 #undef DEF_CILKPLUS_BUILTIN
 #define DEF_CILKPLUS_BUILTIN(ENUM, NAME, TYPE, ATTRS) \
--- gcc/Makefile.in.mp	2013-06-11 19:51:43.780408801 +0200
+++ gcc/Makefile.in	2013-06-11 19:53:37.710224521 +0200
@@ -1150,7 +1150,7 @@  C_COMMON_OBJS = c-family/c-common.o c-fa
   c-family/c-omp.o c-family/c-opts.o c-family/c-pch.o \
   c-family/c-ppoutput.o c-family/c-pragma.o c-family/c-pretty-print.o \
   c-family/c-semantics.o c-family/c-ada-spec.o tree-mudflap.o \
-  c-family/array-notation-common.o
+  c-family/array-notation-common.o c-family/c-ubsan.o
 
 # Language-independent object files.
 # We put the insn-*.o files first so that a parallel make will build
@@ -2021,6 +2021,9 @@  c-family/array-notation-common.o : c-fam
 c-family/stub-objc.o : c-family/stub-objc.c $(CONFIG_H) $(SYSTEM_H) \
 	coretypes.h $(TREE_H) $(C_COMMON_H) c-family/c-objc.h
 
+c-family/c-ubsan.o : c-family/c-ubsan.c $(CONFIG_H) $(SYSTEM_H) \
+	coretypes.h $(TREE_H) $(C_COMMON_H) c-family/c-ubsan.h
+
 default-c.o: config/default-c.c $(CONFIG_H) $(SYSTEM_H) coretypes.h \
   $(C_TARGET_H) $(C_TARGET_DEF_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) \
--- gcc/doc/invoke.texi.mp	2013-06-11 19:51:43.784408831 +0200
+++ gcc/doc/invoke.texi	2013-06-11 19:53:37.761224914 +0200
@@ -5143,6 +5143,11 @@  Memory access instructions will be instr
 data race bugs.
 See @uref{http://code.google.com/p/data-race-test/wiki/ThreadSanitizer} for more details.
 
+@item -fsanitize=undefined
+Enable UndefinedBehaviorSanitizer, a fast undefined behavior detector
+Various computations will be instrumented to detect
+undefined behavior, e.g.@: division by zero or various overflows.
+
 @item -fdump-final-insns@r{[}=@var{file}@r{]}
 @opindex fdump-final-insns
 Dump the final internal representation (RTL) to @var{file}.  If the
--- gcc/cp/typeck.c.mp	2013-06-11 19:51:43.785408839 +0200
+++ gcc/cp/typeck.c	2013-06-12 17:03:19.635943275 +0200
@@ -37,6 +37,7 @@  along with GCC; see the file COPYING3.
 #include "convert.h"
 #include "c-family/c-common.h"
 #include "c-family/c-objc.h"
+#include "c-family/c-ubsan.h"
 #include "params.h"
 
 static tree pfn_from_ptrmemfunc (tree);
@@ -3867,6 +3868,7 @@  cp_build_binary_op (location_t location,
   tree final_type = 0;
 
   tree result;
+  tree orig_type = NULL;
 
   /* Nonzero if this is an operation like MIN or MAX which can
      safely be computed in short if both args are promoted shorts.
@@ -3891,6 +3893,15 @@  cp_build_binary_op (location_t location,
   op0 = orig_op0;
   op1 = orig_op1;
 
+  /* Remember whether we're doing / or %.  */
+  bool doing_div_or_mod = false;
+
+  /* Remember whether we're doing << or >>.  */
+  bool doing_shift = false;
+
+  /* Tree holding instrumentation expression.  */
+  tree instrument_expr = NULL;
+
   if (code == TRUTH_AND_EXPR || code == TRUTH_ANDIF_EXPR
       || code == TRUTH_OR_EXPR || code == TRUTH_ORIF_EXPR
       || code == TRUTH_XOR_EXPR)
@@ -4070,8 +4081,12 @@  cp_build_binary_op (location_t location,
 	{
 	  enum tree_code tcode0 = code0, tcode1 = code1;
 	  tree cop1 = fold_non_dependent_expr_sfinae (op1, tf_none);
+	  cop1 = maybe_constant_value (cop1);
 
-	  warn_for_div_by_zero (location, maybe_constant_value (cop1));
+	  if (!processing_template_decl && tcode0 == INTEGER_TYPE)
+	    doing_div_or_mod = true;
+
+	  warn_for_div_by_zero (location, cop1);
 
 	  if (tcode0 == COMPLEX_TYPE || tcode0 == VECTOR_TYPE)
 	    tcode0 = TREE_CODE (TREE_TYPE (TREE_TYPE (op0)));
@@ -4109,8 +4124,11 @@  cp_build_binary_op (location_t location,
     case FLOOR_MOD_EXPR:
       {
 	tree cop1 = fold_non_dependent_expr_sfinae (op1, tf_none);
+	cop1 = maybe_constant_value (cop1);
 
-	warn_for_div_by_zero (location, maybe_constant_value (cop1));
+	if (!processing_template_decl && code0 == INTEGER_TYPE)
+	  doing_div_or_mod = true;
+	warn_for_div_by_zero (location, cop1);
       }
 
       if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
@@ -4164,6 +4182,7 @@  cp_build_binary_op (location_t location,
 	  if (TREE_CODE (const_op1) != INTEGER_CST)
 	    const_op1 = op1;
 	  result_type = type0;
+	  doing_shift = true;
 	  if (TREE_CODE (const_op1) == INTEGER_CST)
 	    {
 	      if (tree_int_cst_lt (const_op1, integer_zero_node))
@@ -4211,6 +4230,7 @@  cp_build_binary_op (location_t location,
 	  if (TREE_CODE (const_op1) != INTEGER_CST)
 	    const_op1 = op1;
 	  result_type = type0;
+	  doing_shift = true;
 	  if (TREE_CODE (const_op1) == INTEGER_CST)
 	    {
 	      if (tree_int_cst_lt (const_op1, integer_zero_node))
@@ -4765,8 +4785,9 @@  cp_build_binary_op (location_t location,
 
       if (shorten && none_complex)
 	{
+	  orig_type = result_type;
 	  final_type = result_type;
-	  result_type = shorten_binary_op (result_type, op0, op1, 
+	  result_type = shorten_binary_op (result_type, op0, op1,
 					   shorten == -1);
 	}
 
@@ -4832,6 +4853,31 @@  cp_build_binary_op (location_t location,
   if (build_type == NULL_TREE)
     build_type = result_type;
 
+  if (flag_ubsan && !processing_template_decl)
+    {
+      /* OP0 and/or OP1 might have side-effects.  */
+      op0 = cp_save_expr (op0);
+      op1 = cp_save_expr (op1);
+      op0 = maybe_constant_value (fold_non_dependent_expr_sfinae (op0,
+								  tf_none));
+      op1 = maybe_constant_value (fold_non_dependent_expr_sfinae (op1,
+								  tf_none));
+      if (doing_div_or_mod)
+	{
+	  /* For diagnostics we want to use the promoted types without
+	     shorten_binary_op.  So convert the arguments to the
+	     original result_type.  */
+	  if (orig_type != NULL && result_type != orig_type)
+	    {
+	      op0 = cp_convert (orig_type, op0, complain);
+	      op1 = cp_convert (orig_type, op1, complain);
+	    }
+	  instrument_expr = ubsan_instrument_division (location, op0, op1);
+	}
+      else if (doing_shift)
+	instrument_expr = ubsan_instrument_shift (location, code, op0, op1);
+    }
+
   result = build2 (resultcode, build_type, op0, op1);
   result = fold_if_not_in_template (result);
   if (final_type != 0)
@@ -4842,6 +4888,10 @@  cp_build_binary_op (location_t location,
       && !TREE_OVERFLOW_P (op1))
     overflow_warning (location, result);
 
+  if (flag_ubsan && instrument_expr != NULL)
+    result = fold_build2 (COMPOUND_EXPR, TREE_TYPE (result),
+			  instrument_expr, result);
+
   return result;
 }
 
--- gcc/common.opt.mp	2013-06-11 19:51:43.787408855 +0200
+++ gcc/common.opt	2013-06-11 19:53:37.742224768 +0200
@@ -858,6 +858,10 @@  fsanitize=thread
 Common Report Var(flag_tsan)
 Enable ThreadSanitizer, a data race detector
 
+fsanitize=undefined
+Common Report Var(flag_ubsan)
+Enable UndefinedBehaviorSanitizer, an undefined behavior detector
+
 fasynchronous-unwind-tables
 Common Report Var(flag_asynchronous_unwind_tables) Optimization
 Generate unwind tables that are exact at each instruction boundary
--- gcc/builtin-attrs.def.mp	2013-06-11 19:51:43.791408885 +0200
+++ gcc/builtin-attrs.def	2013-06-11 19:53:37.717224576 +0200
@@ -83,6 +83,7 @@  DEF_LIST_INT_INT (5,6)
 #undef DEF_LIST_INT_INT
 
 /* Construct trees for identifiers.  */
+DEF_ATTR_IDENT (ATTR_COLD, "cold")
 DEF_ATTR_IDENT (ATTR_CONST, "const")
 DEF_ATTR_IDENT (ATTR_FORMAT, "format")
 DEF_ATTR_IDENT (ATTR_FORMAT_ARG, "format_arg")
@@ -130,6 +131,8 @@  DEF_ATTR_TREE_LIST (ATTR_NORETURN_NOTHRO
 			ATTR_NULL, ATTR_NOTHROW_LIST)
 DEF_ATTR_TREE_LIST (ATTR_NORETURN_NOTHROW_LEAF_LIST, ATTR_NORETURN,\
 			ATTR_NULL, ATTR_NOTHROW_LEAF_LIST)
+DEF_ATTR_TREE_LIST (ATTR_COLD_NORETURN_NOTHROW_LEAF_LIST, ATTR_COLD,\
+			ATTR_NULL, ATTR_NORETURN_NOTHROW_LEAF_LIST)
 DEF_ATTR_TREE_LIST (ATTR_CONST_NORETURN_NOTHROW_LEAF_LIST, ATTR_CONST,\
 			ATTR_NULL, ATTR_NORETURN_NOTHROW_LEAF_LIST)
 DEF_ATTR_TREE_LIST (ATTR_MALLOC_NOTHROW_LIST, ATTR_MALLOC,	\
--- gcc/c/c-typeck.c.mp	2013-06-11 19:51:43.789408869 +0200
+++ gcc/c/c-typeck.c	2013-06-12 17:03:32.582989258 +0200
@@ -39,6 +39,7 @@  along with GCC; see the file COPYING3.
 #include "gimple.h"
 #include "c-family/c-objc.h"
 #include "c-family/c-common.h"
+#include "c-family/c-ubsan.h"
 
 /* Possible cases of implicit bad conversions.  Used to select
    diagnostic messages in convert_for_assignment.  */
@@ -9527,6 +9528,15 @@  build_binary_op (location_t location, en
      operands to truth-values.  */
   bool boolean_op = false;
 
+  /* Remember whether we're doing / or %.  */
+  bool doing_div_or_mod = false;
+
+  /* Remember whether we're doing << or >>.  */
+  bool doing_shift = false;
+
+  /* Tree holding instrumentation expression.  */
+  tree instrument_expr = NULL;
+
   if (location == UNKNOWN_LOCATION)
     location = input_location;
 
@@ -9728,6 +9738,7 @@  build_binary_op (location_t location, en
     case FLOOR_DIV_EXPR:
     case ROUND_DIV_EXPR:
     case EXACT_DIV_EXPR:
+      doing_div_or_mod = true;
       warn_for_div_by_zero (location, op1);
 
       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
@@ -9775,6 +9786,7 @@  build_binary_op (location_t location, en
 
     case TRUNC_MOD_EXPR:
     case FLOOR_MOD_EXPR:
+      doing_div_or_mod = true;
       warn_for_div_by_zero (location, op1);
 
       if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE
@@ -9873,6 +9885,7 @@  build_binary_op (location_t location, en
       else if ((code0 == INTEGER_TYPE || code0 == FIXED_POINT_TYPE)
 	  && code1 == INTEGER_TYPE)
 	{
+	  doing_shift = true;
 	  if (TREE_CODE (op1) == INTEGER_CST)
 	    {
 	      if (tree_int_cst_sgn (op1) < 0)
@@ -9925,6 +9938,7 @@  build_binary_op (location_t location, en
       else if ((code0 == INTEGER_TYPE || code0 == FIXED_POINT_TYPE)
 	  && code1 == INTEGER_TYPE)
 	{
+	  doing_shift = true;
 	  if (TREE_CODE (op1) == INTEGER_CST)
 	    {
 	      if (tree_int_cst_sgn (op1) < 0)
@@ -10469,6 +10483,17 @@  build_binary_op (location_t location, en
 	return error_mark_node;
     }
 
+  if (flag_ubsan)
+    {
+      /* OP0 and/or OP1 might have side-effects.  */
+      op0 = c_save_expr (op0);
+      op1 = c_save_expr (op1);
+      if (doing_div_or_mod)
+	instrument_expr = ubsan_instrument_division (location, op0, op1);
+      else if (doing_shift)
+	instrument_expr = ubsan_instrument_shift (location, code, op0, op1);
+    }
+
   /* Treat expressions in initializers specially as they can't trap.  */
   if (int_const_or_overflow)
     ret = (require_constant_value
@@ -10492,6 +10517,11 @@  build_binary_op (location_t location, en
   if (semantic_result_type)
     ret = build1 (EXCESS_PRECISION_EXPR, semantic_result_type, ret);
   protected_set_expr_location (ret, location);
+
+  if (flag_ubsan && instrument_expr != NULL)
+    ret = fold_build2 (COMPOUND_EXPR, TREE_TYPE (ret),
+		       instrument_expr, ret);
+
   return ret;
 }
 
--- gcc/asan.c.mp	2013-06-11 19:51:43.793408901 +0200
+++ gcc/asan.c	2013-06-11 19:53:37.713224545 +0200
@@ -2034,6 +2034,9 @@  initialize_sanitizer_builtins (void)
   tree BT_FN_VOID = build_function_type_list (void_type_node, NULL_TREE);
   tree BT_FN_VOID_PTR
     = build_function_type_list (void_type_node, ptr_type_node, NULL_TREE);
+  tree BT_FN_VOID_PTR_PTR_PTR
+    = build_function_type_list (void_type_node, ptr_type_node,
+				ptr_type_node, ptr_type_node, NULL_TREE);
   tree BT_FN_VOID_PTR_PTRMODE
     = build_function_type_list (void_type_node, ptr_type_node,
 				build_nonstandard_integer_type (POINTER_SIZE,
@@ -2099,6 +2102,9 @@  initialize_sanitizer_builtins (void)
 #undef ATTR_TMPURE_NORETURN_NOTHROW_LEAF_LIST
 #define ATTR_TMPURE_NORETURN_NOTHROW_LEAF_LIST \
   ECF_TM_PURE | ATTR_NORETURN_NOTHROW_LEAF_LIST
+#undef ATTR_COLD_NORETURN_NOTHROW_LEAF_LIST
+#define ATTR_COLD_NORETURN_NOTHROW_LEAF_LIST \
+  /* ECF_COLD missing */ ATTR_NORETURN_NOTHROW_LEAF_LIST
 #undef DEF_SANITIZER_BUILTIN
 #define DEF_SANITIZER_BUILTIN(ENUM, NAME, TYPE, ATTRS) \
   decl = add_builtin_function ("__builtin_" NAME, TYPE, ENUM,		\