Hi, David and Rong, thanks a lot! Modified code uploaded as patch 8
and is also included at the end of email body.
Ref - http://codereview.appspot.com/5461043
Regards,
-Han
== Patch start
diff --git a/gcc/cfgexpand.c b/gcc/cfgexpand.c
index 6d31e90..131c1b9 100644
--- a/gcc/cfgexpand.c
+++ b/gcc/cfgexpand.c
@@ -1524,15 +1524,39 @@ 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. */
{
@@ -1565,6 +1589,23 @@ 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. */
@@ -1655,11 +1696,18 @@ 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_protector == 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/common.opt b/gcc/common.opt
index ec1dbd1..b79b8cc 100644
--- a/gcc/common.opt
+++ b/gcc/common.opt
@@ -1835,8 +1835,12 @@ 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/doc/invoke.texi b/gcc/doc/invoke.texi
index e3d3789..607a7a5 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -400,8 +400,8 @@ 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
--fthread-jumps -ftracer -ftree-bit-ccp @gol
+-fstack-protector-strong -fstack-protector-all -fstrict-aliasing @gol
+-fstrict-overflow -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
-ftree-forwprop -ftree-fre -ftree-loop-if-convert @gol
@@ -8443,6 +8443,12 @@ functions with buffers larger than 8 bytes.
The guards are initialized
when a function is entered and then checked when the function exits.
If a guard check fails, an error message is printed and the program exits.
+@item -fstack-protector-strong
+@opindex fstack-protector-strong
+Like @option{-fstack-protector} but includes
