[stackprotector] Add command line option -fstack-protector-strong

This option has the following effects:
 * It adds the sspstrong IR attribute to each function within the CU.
 * It defines the macro __SSP_STRONG__ with the value of 2.

Differential Revision: http://llvm-reviews.chandlerc.com/D2717

llvm-svn: 201120

9 files changed, 36 insertions, 10 deletions

diff --git a/clang/include/clang/Basic/LangOptions.h b/clang/include/clang/Basic/LangOptions.h
index d4e8b4eb5ba..7b2b18d5774 100644
--- a/clang/include/clang/Basic/LangOptions.h
+++ b/clang/include/clang/Basic/LangOptions.h
@@ -58,7 +58,7 @@ public:
   typedef clang::Visibility Visibility;
   
   enum GCMode { NonGC, GCOnly, HybridGC };
-  enum StackProtectorMode { SSPOff, SSPOn, SSPReq };
+  enum StackProtectorMode { SSPOff, SSPOn, SSPStrong, SSPReq };
   
   enum SignedOverflowBehaviorTy {
     SOB_Undefined,  // Default C standard behavior.
diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index d860d8f7dbc..de31361b25e 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -675,7 +675,8 @@ def fno_show_source_location : Flag<["-"], "fno-show-source-location">, Group<f_
   Flags<[CC1Option]>, HelpText<"Do not include source location information with diagnostics">;
 def fno_spell_checking : Flag<["-"], "fno-spell-checking">, Group<f_Group>,
   Flags<[CC1Option]>, HelpText<"Disable spell-checking">;
-def fno_stack_protector : Flag<["-"], "fno-stack-protector">, Group<f_Group>;
+def fno_stack_protector : Flag<["-"], "fno-stack-protector">, Group<f_Group>,
+  HelpText<"Disable the use of stack protectors">;
 def fno_strict_aliasing : Flag<["-"], "fno-strict-aliasing">, Group<f_Group>;
 def fstruct_path_tbaa : Flag<["-"], "fstruct-path-tbaa">, Group<f_Group>;
 def fno_struct_path_tbaa : Flag<["-"], "fno-struct-path-tbaa">, Group<f_Group>;
@@ -773,8 +774,12 @@ def fsigned_char : Flag<["-"], "fsigned-char">, Group<f_Group>;
 def fno_signed_char : Flag<["-"], "fno-signed-char">, Flags<[CC1Option]>,
     Group<clang_ignored_f_Group>, HelpText<"Char is unsigned">;
 def fsplit_stack : Flag<["-"], "fsplit-stack">, Group<f_Group>;
-def fstack_protector_all : Flag<["-"], "fstack-protector-all">, Group<f_Group>;
-def fstack_protector : Flag<["-"], "fstack-protector">, Group<f_Group>;
+def fstack_protector_all : Flag<["-"], "fstack-protector-all">, Group<f_Group>,
+  HelpText<"Force the usage of stack protectors for all functions">;
+def fstack_protector_strong : Flag<["-"], "fstack-protector-strong">, Group<f_Group>,
+  HelpText<"Use a strong heuristic to apply stack protectors to functions">;
+def fstack_protector : Flag<["-"], "fstack-protector">, Group<f_Group>,
+  HelpText<"Enable stack protectors for functions potentially vulnerable to stack smashing">;
 def fstandalone_debug : Flag<["-"], "fstandalone-debug">, Group<f_Group>, Flags<[CC1Option]>,
   HelpText<"Emit full debug info for all types used by the program">;
 def fno_standalone_debug : Flag<["-"], "fno-standalone-debug">, Group<f_Group>, Flags<[CC1Option]>,
diff --git a/clang/include/clang/Driver/ToolChain.h b/clang/include/clang/Driver/ToolChain.h
index ceb1c76e65d..e775f630e10 100644
--- a/clang/include/clang/Driver/ToolChain.h
+++ b/clang/include/clang/Driver/ToolChain.h
@@ -196,7 +196,7 @@ public:
   virtual bool UseObjCMixedDispatch() const { return false; }
 
   /// GetDefaultStackProtectorLevel - Get the default stack protector level for
-  /// this tool chain (0=off, 1=on, 2=all).
+  /// this tool chain (0=off, 1=on, 2=strong, 3=all).
   virtual unsigned GetDefaultStackProtectorLevel(bool KernelOrKext) const {
     return 0;
   }
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index c0c1219f8d2..7b1eab9721d 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -651,6 +651,8 @@ void CodeGenModule::SetLLVMFunctionAttributesForDefinition(const Decl *D,
 
   if (LangOpts.getStackProtector() == LangOptions::SSPOn)
     B.addAttribute(llvm::Attribute::StackProtect);
+  else if (LangOpts.getStackProtector() == LangOptions::SSPStrong)
+    B.addAttribute(llvm::Attribute::StackProtectStrong);
   else if (LangOpts.getStackProtector() == LangOptions::SSPReq)
     B.addAttribute(llvm::Attribute::StackProtectReq);
 
diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index d2bb9ba5327..5792f42b6fc 100644
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -10,6 +10,7 @@
 #include "Tools.h"
 #include "InputInfo.h"
 #include "ToolChains.h"
+#include "clang/Basic/LangOptions.h"
 #include "clang/Basic/ObjCRuntime.h"
 #include "clang/Basic/Version.h"
 #include "clang/Driver/Action.h"
@@ -3114,11 +3115,14 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
   unsigned StackProtectorLevel = 0;
   if (Arg *A = Args.getLastArg(options::OPT_fno_stack_protector,
                                options::OPT_fstack_protector_all,
+                               options::OPT_fstack_protector_strong,
                                options::OPT_fstack_protector)) {
     if (A->getOption().matches(options::OPT_fstack_protector))
-      StackProtectorLevel = 1;
+      StackProtectorLevel = LangOptions::SSPOn;
+    else if (A->getOption().matches(options::OPT_fstack_protector_strong))
+      StackProtectorLevel = LangOptions::SSPStrong;
     else if (A->getOption().matches(options::OPT_fstack_protector_all))
-      StackProtectorLevel = 2;
+      StackProtectorLevel = LangOptions::SSPReq;
   } else {
     StackProtectorLevel =
       getToolChain().GetDefaultStackProtectorLevel(KernelOrKext);
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 3c75dd5249e..034730fe187 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -1435,7 +1435,8 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
     break;
   case 0: Opts.setStackProtector(LangOptions::SSPOff); break;
   case 1: Opts.setStackProtector(LangOptions::SSPOn);  break;
-  case 2: Opts.setStackProtector(LangOptions::SSPReq); break;
+  case 2: Opts.setStackProtector(LangOptions::SSPStrong); break;
+  case 3: Opts.setStackProtector(LangOptions::SSPReq); break;
   }
 
   // Parse -fsanitize= arguments.
diff --git a/clang/lib/Frontend/InitPreprocessor.cpp b/clang/lib/Frontend/InitPreprocessor.cpp
index 7b3166da081..f975c9f6955 100644
--- a/clang/lib/Frontend/InitPreprocessor.cpp
+++ b/clang/lib/Frontend/InitPreprocessor.cpp
@@ -695,8 +695,10 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
 
   if (LangOpts.getStackProtector() == LangOptions::SSPOn)
     Builder.defineMacro("__SSP__");
+  else if (LangOpts.getStackProtector() == LangOptions::SSPStrong)
+    Builder.defineMacro("__SSP_STRONG__", "2");
   else if (LangOpts.getStackProtector() == LangOptions::SSPReq)
-    Builder.defineMacro("__SSP_ALL__", "2");
+    Builder.defineMacro("__SSP_ALL__", "3");
 
   if (FEOpts.ProgramAction == frontend::RewriteObjC)
     Builder.defineMacro("__weak", "__attribute__((objc_gc(weak)))");
diff --git a/clang/test/CodeGen/stack-protector.c b/clang/test/CodeGen/stack-protector.c
index e47e5b321b6..2fb9b2cf7e6 100644
--- a/clang/test/CodeGen/stack-protector.c
+++ b/clang/test/CodeGen/stack-protector.c
@@ -2,7 +2,9 @@
 // NOSSP: define void @test1(i8* %msg) #0 {
 // RUN: %clang_cc1 -emit-llvm -o - %s -stack-protector 1 | FileCheck -check-prefix=WITHSSP %s
 // WITHSSP: define void @test1(i8* %msg) #0 {
-// RUN: %clang_cc1 -emit-llvm -o - %s -stack-protector 2 | FileCheck -check-prefix=SSPREQ %s
+// RUN: %clang_cc1 -emit-llvm -o - %s -stack-protector 2 | FileCheck -check-prefix=SSPSTRONG %s
+// SSPSTRONG: define void @test1(i8* %msg) #0 {
+// RUN: %clang_cc1 -emit-llvm -o - %s -stack-protector 3 | FileCheck -check-prefix=SSPREQ %s
 // SSPREQ: define void @test1(i8* %msg) #0 {
 
 typedef __SIZE_TYPE__ size_t;
@@ -21,4 +23,6 @@ void test1(const char *msg) {
 
 // WITHSSP: attributes #{{.*}} = { nounwind ssp{{.*}} }
 
+// SSPSTRONG: attributes #{{.*}} = { nounwind sspstrong{{.*}} }
+
 // SSPREQ: attributes #{{.*}} = { nounwind sspreq{{.*}} }
diff --git a/clang/test/Driver/stack-protector.c b/clang/test/Driver/stack-protector.c
index 2eb0f53530a..e6212acf3a1 100644
--- a/clang/test/Driver/stack-protector.c
+++ b/clang/test/Driver/stack-protector.c
@@ -15,3 +15,11 @@
 
 // RUN: %clang -target i386-pc-openbsd -fno-stack-protector -### %s 2>&1 | FileCheck %s -check-prefix=OPENBSD_OFF
 // OPENBSD_OFF-NOT: "-stack-protector"
+
+// RUN: %clang -fstack-protector-strong -### %s 2>&1 | FileCheck %s -check-prefix=SSP-STRONG
+// SSP-STRONG: "-stack-protector" "2"
+// SSP-STRONG-NOT: "-stack-protector-buffer-size" 
+
+// RUN: %clang -fstack-protector-all -### %s 2>&1 | FileCheck %s -check-prefix=SSP-ALL
+// SSP-ALL: "-stack-protector" "3"
+// SSP-ALL-NOT: "-stack-protector-buffer-size"