[4.8] Add -mstack-protector-guard= to x86 compilers

To choose between "global" (default) and "tls" (new)
for -fstack-protector, -fstack-protector-all, and
-fstack-protector-strong (GCC 4.6+).

Note that this alone doesn't enable any -fstack-protector*

For NDK: The default "global" generates code backward
compatible with older bionic

For AOSP: build may add "-mstack-protector-guard=tls" to
build platform code with new bionic (*1)

Related CL:
  ad88a0863110798cef5169dcf917e18b967a7cf6 (*1)
  e804643b6dfcfb5842dea4b714601c6dd89f4944

Change-Id: I341c9022530b37ca289d94e1174dfa86a8eaa1bf

4 files changed, 29 insertions, 4 deletions

diff --git a/gcc-4.8/gcc/config/i386/i386-opts.h b/gcc-4.8/gcc/config/i386/i386-opts.h
index 11c08457d..3f3ce13be 100644
--- a/gcc-4.8/gcc/config/i386/i386-opts.h
+++ b/gcc-4.8/gcc/config/i386/i386-opts.h
@@ -85,4 +85,9 @@ enum ix86_veclibabi {
   ix86_veclibabi_type_acml
 };
 
+enum stack_protector_guard {
+  SSP_TLS,      /* per-thread canary at %gs:20 */
+  SSP_GLOBAL,   /* global canary */
+};
+
 #endif
diff --git a/gcc-4.8/gcc/config/i386/i386.c b/gcc-4.8/gcc/config/i386/i386.c
index b835c5da2..a8212f54b 100644
--- a/gcc-4.8/gcc/config/i386/i386.c
+++ b/gcc-4.8/gcc/config/i386/i386.c
@@ -3922,6 +3922,12 @@ ix86_option_override_internal (bool main_args_p)
   if (main_args_p)
     target_option_default_node = target_option_current_node
       = build_target_option_node ();
+
+  /* Handle stack protector */
+  if (!global_options_set.x_ix86_stack_protector_guard)
+    {
+      ix86_stack_protector_guard = TARGET_HAS_BIONIC? SSP_GLOBAL : SSP_TLS;
+    }
 }
 
 /* Implement the TARGET_OPTION_OVERRIDE hook.  */
diff --git a/gcc-4.8/gcc/config/i386/i386.md b/gcc-4.8/gcc/config/i386/i386.md
index 24d1012d5..247e6f9ec 100644
--- a/gcc-4.8/gcc/config/i386/i386.md
+++ b/gcc-4.8/gcc/config/i386/i386.md
@@ -17599,7 +17599,7 @@
 (define_expand "stack_protect_set"
   [(match_operand 0 "memory_operand")
    (match_operand 1 "memory_operand")]
-  "!TARGET_HAS_BIONIC"
+  "ix86_stack_protector_guard == SSP_TLS"
 {
   rtx (*insn)(rtx, rtx);
 
@@ -17624,7 +17624,7 @@
 		    UNSPEC_SP_SET))
    (set (match_scratch:PTR 2 "=&r") (const_int 0))
    (clobber (reg:CC FLAGS_REG))]
-  "!TARGET_HAS_BIONIC"
+  "ix86_stack_protector_guard == SSP_TLS"
   "mov{<imodesuffix>}\t{%1, %2|%2, %1}\;mov{<imodesuffix>}\t{%2, %0|%0, %2}\;xor{l}\t%k2, %k2"
   [(set_attr "type" "multi")])
 
@@ -17642,7 +17642,7 @@
   [(match_operand 0 "memory_operand")
    (match_operand 1 "memory_operand")
    (match_operand 2)]
-  "!TARGET_HAS_BIONIC"
+  "ix86_stack_protector_guard == SSP_TLS"
 {
   rtx flags = gen_rtx_REG (CCZmode, FLAGS_REG);
 
@@ -17672,7 +17672,7 @@
 		     (match_operand:PTR 2 "memory_operand" "m")]
 		    UNSPEC_SP_TEST))
    (clobber (match_scratch:PTR 3 "=&r"))]
-  "!TARGET_HAS_BIONIC"
+  "ix86_stack_protector_guard == SSP_TLS"
   "mov{<imodesuffix>}\t{%1, %3|%3, %1}\;xor{<imodesuffix>}\t{%2, %3|%3, %2}"
   [(set_attr "type" "multi")])
 
diff --git a/gcc-4.8/gcc/config/i386/i386.opt b/gcc-4.8/gcc/config/i386/i386.opt
index 084a24863..f5ad69e26 100644
--- a/gcc-4.8/gcc/config/i386/i386.opt
+++ b/gcc-4.8/gcc/config/i386/i386.opt
@@ -626,3 +626,17 @@ Split 32-byte AVX unaligned store
 mrtm
 Target Report Mask(ISA_RTM) Var(ix86_isa_flags) Save
 Support RTM built-in functions and code generation
+
+mstack-protector-guard=
+Target RejectNegative Joined Enum(stack_protector_guard) Var(ix86_stack_protector_guard) Init(SSP_TLS)
+Use given stack-protector guard
+
+Enum
+Name(stack_protector_guard) Type(enum stack_protector_guard)
+Known stack protector guard (for use with the -mstack-protector-guard= option):
+
+EnumValue
+Enum(stack_protector_guard) String(tls) Value(SSP_TLS)
+
+EnumValue
+Enum(stack_protector_guard) String(global) Value(SSP_GLOBAL)