5 files changed, 235 insertions, 7 deletions
diff --git a/gcc-4.7/gcc/cfgexpand.c b/gcc-4.7/gcc/cfgexpand.c
index bde15f696..53066e031 100644
--- a/gcc-4.7/gcc/cfgexpand.c
+++ b/gcc-4.7/gcc/cfgexpand.c
@@ -1508,15 +1508,39 @@ estimated_stack_frame_size (struct cgraph_node *node)
   return size;
 }
 
+/* Helper routine to check if a record or union contains an array field. */
+
+static int
+record_or_union_type_has_array_p (const_tree tree_type)
+{
+  tree fields = TYPE_FIELDS (tree_type);
+  tree f;
+
+  for (f = fields; f; f = DECL_CHAIN (f))
+    {
+      if (TREE_CODE (f) == FIELD_DECL)
+	{
+	  tree field_type = TREE_TYPE (f);
+	  if (RECORD_OR_UNION_TYPE_P (field_type))
+	    return record_or_union_type_has_array_p (field_type);
+	  if (TREE_CODE (field_type) == ARRAY_TYPE)
+	    return 1;
+	}
+    }
+  return 0;
+}
+
 /* Expand all variables used in the function.  */
 
 static void
 expand_used_vars (void)
 {
   tree var, outer_block = DECL_INITIAL (current_function_decl);
+  referenced_var_iterator rvi;
   VEC(tree,heap) *maybe_local_decls = NULL;
   unsigned i;
   unsigned len;
+  int gen_stack_protect_signal = 0;
 
   /* Compute the phase of the stack frame for this function.  */
   {
@@ -1549,6 +1573,23 @@ expand_used_vars (void)
 	}
     }
 
+  FOR_EACH_REFERENCED_VAR (cfun, var, rvi)
+    if (!is_global_var (var))
+      {
+	tree var_type = TREE_TYPE (var);
+	/* Examine local referenced variables that have their addresses taken,
+	   contain an array, or are arrays.  */
+	if (TREE_CODE (var) == VAR_DECL
+	    && (TREE_CODE (var_type) == ARRAY_TYPE
+		|| TREE_ADDRESSABLE (var)
+		|| (RECORD_OR_UNION_TYPE_P (var_type)
+		    && record_or_union_type_has_array_p (var_type))))
+	  {
+	    ++gen_stack_protect_signal;
+	    break;
+	  }
+      }
+
   /* At this point all variables on the local_decls with TREE_USED
      set are not associated with any block scope.  Lay them out.  */
 
@@ -1639,11 +1680,18 @@ expand_used_vars (void)
 	dump_stack_var_partition ();
     }
 
-  /* There are several conditions under which we should create a
-     stack guard: protect-all, alloca used, protected decls present.  */
-  if (flag_stack_protect == 2
-      || (flag_stack_protect
-	  && (cfun->calls_alloca || has_protected_decls)))
+  /* Create stack guard, if
+     a) "-fstack-protector-all" - always;
+     b) "-fstack-protector-strong" - if there are arrays, memory
+     references to local variables, alloca used, or protected decls present;
+     c) "-fstack-protector" - if alloca used, or protected decls present  */
+  if (flag_stack_protect == 3  /* -fstack-protector-all  */
+      || (flag_stack_protect == 2  /* -fstack-protector-strong  */
+	  && (gen_stack_protect_signal || cfun->calls_alloca
+	      || has_protected_decls))
+      || (flag_stack_protect == 1  /* -fstack-protector  */
+	  && (cfun->calls_alloca
+	      || has_protected_decls)))
     create_stack_guard ();
 
   /* Assign rtl to each variable based on these partitions.  */
diff --git a/gcc-4.7/gcc/common.opt b/gcc-4.7/gcc/common.opt
index ba1cf5ba8..97ab0f8af 100644
--- a/gcc-4.7/gcc/common.opt
+++ b/gcc-4.7/gcc/common.opt
@@ -1832,8 +1832,12 @@ fstack-protector
 Common Report Var(flag_stack_protect, 1)
 Use propolice as a stack protection method
 
-fstack-protector-all
+fstack-protector-strong
 Common Report RejectNegative Var(flag_stack_protect, 2)
+Use a smart stack protection method for certain functions
+
+fstack-protector-all
+Common Report RejectNegative Var(flag_stack_protect, 3)
 Use a stack protection method for every function
 
 fstack-usage
diff --git a/gcc-4.7/gcc/doc/invoke.texi b/gcc-4.7/gcc/doc/invoke.texi
index 5d676481e..135cc2944 100644
--- a/gcc-4.7/gcc/doc/invoke.texi
+++ b/gcc-4.7/gcc/doc/invoke.texi
@@ -401,7 +401,7 @@ Objective-C and Objective-C++ Dialects}.
 -fsel-sched-pipelining -fsel-sched-pipelining-outer-loops @gol
 -fshrink-wrap -fsignaling-nans -fsingle-precision-constant @gol
 -fsplit-ivs-in-unroller -fsplit-wide-types -fstack-protector @gol
--fstack-protector-all -fstrict-aliasing -fstrict-overflow @gol
+-fstack-protector-all -fstack-protector-strong -fstrict-aliasing -fstrict-overflow @gol
 -fthread-jumps -ftracer -ftree-bit-ccp @gol
 -ftree-builtin-call-dce -ftree-ccp -ftree-ch -ftree-copy-prop @gol
 -ftree-copyrename -ftree-dce -ftree-dominator-opts -ftree-dse @gol
@@ -8489,6 +8489,12 @@ If a guard check fails, an error message is printed and the program exits.
 @opindex fstack-protector-all
 Like @option{-fstack-protector} except that all functions are protected.
 
+@item -fstack-protector-strong
+@opindex fstack-protector-strong
+Like @option{-fstack-protector} but includes additional functions to be
+protected - those that have local array definitions, or have references to
+local frame addresses.
+
 @item -fsection-anchors
 @opindex fsection-anchors
 Try to reduce the number of symbolic address calculations by using
diff --git a/gcc-4.7/gcc/testsuite/g++.dg/fstack-protector-strong.C b/gcc-4.7/gcc/testsuite/g++.dg/fstack-protector-strong.C
new file mode 100644
index 000000000..a4f0f8163
--- /dev/null
+++ b/gcc-4.7/gcc/testsuite/g++.dg/fstack-protector-strong.C
@@ -0,0 +1,35 @@
+/* Test that stack protection is done on chosen functions. */
+
+/* { dg-do compile { target i?86-*-* x86_64-*-* } } */
+/* { dg-options "-O2 -fstack-protector-strong" } */
+
+class A
+{
+public:
+  A() {}
+  ~A() {}
+  void method();
+  int state;
+};
+
+/* Frame address exposed to A::method via "this". */
+int
+foo1 ()
+{
+  A a;
+  a.method ();
+  return a.state;
+}
+
+/* Possible destroying foo2's stack via &a. */
+int
+global_func (A& a);
+
+/* Frame address exposed to global_func. */
+int foo2 ()
+{
+  A a;
+  return global_func (a);
+}
+
+/* { dg-final { scan-assembler-times "stack_chk_fail" 2 } } */
diff --git a/gcc-4.7/gcc/testsuite/gcc.dg/fstack-protector-strong.c b/gcc-4.7/gcc/testsuite/gcc.dg/fstack-protector-strong.c
new file mode 100644
index 000000000..5a5cf98a7
--- /dev/null
+++ b/gcc-4.7/gcc/testsuite/gcc.dg/fstack-protector-strong.c
@@ -0,0 +1,135 @@
+/* Test that stack protection is done on chosen functions. */
+
+/* { dg-do compile { target i?86-*-* x86_64-*-* } } */
+/* { dg-options "-O2 -fstack-protector-strong" } */
+
+#include<string.h>
+#include<stdlib.h>
+
+extern int g0;
+extern int* pg0;
+int
+goo (int *);
+int
+hoo (int);
+
+/* Function frame address escaped function call. */
+int
+foo1 ()
+{
+  int i;
+  return goo (&i);
+}
+
+struct ArrayStruct
+{
+  int a;
+  int array[10];
+};
+
+struct AA
+{
+  int b;
+  struct ArrayStruct as;
+};
+
+/* Function frame contains array. */
+int
+foo2 ()
+{
+  struct AA aa;
+  int i;
+  for (i = 0; i < 10; ++i)
+    {
+      aa.as.array[i] = i * (i-1) + i / 2;
+    }
+  return aa.as.array[5];
+}
+
+/* Address computation based on a function frame address. */
+int
+foo3 ()
+{
+  int a;
+  int *p;
+  p = &a + 5;
+  return goo (p);
+}
+
+/* Address cast based on a function frame address. */
+int
+foo4 ()
+{
+  int a;
+  return goo (g0 << 2 ? (int *)(3 * (long)(void *)(&a)) : 0);
+}
+
+/* Address cast based on a local array. */
+int
+foo5 ()
+{
+  short array[10];
+  return goo ((int *)(array + 5));
+}
+
+struct BB
+{
+  int one;
+  int two;
+  int three;
+};
+
+/* Address computaton based on a function frame address.*/
+int
+foo6 ()
+{
+  struct BB bb;
+  return goo (&bb.one + sizeof(int));
+}
+
+/* Function frame address escaped via global variable. */
+int
+foo7 ()
+{
+  int a;
+  pg0 = &a;
+  goo (pg0);
+  return *pg0;
+}
+
+/* Check that this covers -fstack-protector. */
+int
+foo8 ()
+{
+  char base[100];
+  memcpy ((void *)base, (const void *)pg0, 105);
+  return (int)(base[32]);
+}
+
+/* Check that this covers -fstack-protector. */
+int
+foo9 ()
+{
+  char* p = alloca (100);
+  return goo ((int *)(p + 50));
+}
+
+int
+global2 (struct BB* pbb);
+
+/* Address taken on struct. */
+int
+foo10 ()
+{
+  struct BB bb;
+  int i;
+  bb.one = global2 (&bb);
+  for (i = 0; i < 10; ++i)
+    {
+      bb.two = bb.one + bb.two;
+      bb.three = bb.one + bb.two + bb.three;
+    }
+  return bb.three;
+}
+
+/* { dg-final { scan-assembler-times "stack_chk_fail" 10 } } */