Added tests for __attribute__((no_safe_stack)).

http://reviews.llvm.org/D6095

Files:
  include/clang/Basic/Attr.td
  include/clang/Basic/AttrDocs.td
  include/clang/Basic/LangOptions.def
  include/clang/Basic/LangOptions.h
  include/clang/Driver/Options.td
  lib/CodeGen/CodeGenModule.cpp
  lib/Driver/ToolChains.cpp
  lib/Driver/Tools.cpp
  lib/Frontend/CompilerInvocation.cpp
  lib/Frontend/InitPreprocessor.cpp
  lib/Sema/SemaDeclAttr.cpp
  runtime/compiler-rt/Makefile
  test/CodeGen/safestack-attr.cpp
  test/CodeGen/stack-protector.c
  test/Driver/safestack.c
  test/SemaCXX/attr-no-safestack.cpp
Index: include/clang/Basic/Attr.td
===================================================================
--- include/clang/Basic/Attr.td
+++ include/clang/Basic/Attr.td
@@ -1317,6 +1317,13 @@
   let Documentation = [Undocumented];
 }
 
+// Attribute to disable SafeStack (or equivalent) instrumentation.
+def NoSafeStack : InheritableAttr {
+  let Spellings = [GCC<"no_safe_stack">];
+  let Subjects = SubjectList<[Function], ErrorDiag>;
+  let Documentation = [NoSafeStackDocs];
+}
+
 // Attribute to disable AddressSanitizer (or equivalent) checks.
 def NoSanitizeAddress : InheritableAttr {
   let Spellings = [GCC<"no_address_safety_analysis">,
Index: include/clang/Basic/AttrDocs.td
===================================================================
--- include/clang/Basic/AttrDocs.td
+++ include/clang/Basic/AttrDocs.td
@@ -860,6 +860,17 @@
   }];
 }
 
+def NoSafeStackDocs : Documentation {
+  let Category = DocCatFunction;
+  let Content = [{
+Use ``__attribute__((no_safe_stack))`` on a function declaration to specify
+that the safe stack instrumentation should not be applied to that function,
+even if enabled globally (see -fsafe-stack flag). This attribute may be
+required for functions that make assumptions about the exact layout of their
+stack frames.
+  }];
+}
+
 def NoSanitizeAddressDocs : Documentation {
   let Category = DocCatFunction;
   // This function has multiple distinct spellings, and so it requires a custom
Index: include/clang/Basic/LangOptions.def
===================================================================
--- include/clang/Basic/LangOptions.def
+++ include/clang/Basic/LangOptions.def
@@ -192,7 +192,7 @@
              "value symbol visibility")
 ENUM_LANGOPT(TypeVisibilityMode, Visibility, 3, DefaultVisibility,
              "type symbol visibility")
-ENUM_LANGOPT(StackProtector, StackProtectorMode, 2, SSPOff,
+ENUM_LANGOPT(StackProtector, StackProtectorMode, 3, SSPOff,
              "stack protector mode")
 ENUM_LANGOPT(SignedOverflowBehavior, SignedOverflowBehaviorTy, 2, SOB_Undefined,
              "signed integer overflow handling")
Index: include/clang/Basic/LangOptions.h
===================================================================
--- include/clang/Basic/LangOptions.h
+++ include/clang/Basic/LangOptions.h
@@ -66,7 +66,7 @@
   typedef clang::Visibility Visibility;
   
   enum GCMode { NonGC, GCOnly, HybridGC };
-  enum StackProtectorMode { SSPOff, SSPOn, SSPStrong, SSPReq };
+  enum StackProtectorMode { SSPOff, SSPOn, SSPStrong, SSPReq, SSPSafeStack };
   
   enum SignedOverflowBehaviorTy {
     SOB_Undefined,  // Default C standard behavior.
Index: include/clang/Driver/Options.td
===================================================================
--- include/clang/Driver/Options.td
+++ include/clang/Driver/Options.td
@@ -864,6 +864,10 @@
   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 fsafe_stack : Flag<["-"], "fsafe-stack">, Group<f_Group>,
+  HelpText<"Enable safe stack protection against stack-based memory corruption errors">;
+def fno_safe_stack : Flag<["-"], "fno-safe-stack">, Group<f_Group>,
+  HelpText<"Disable safe stack protection against stack-based memory corruption errors">;
 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]>,
Index: lib/CodeGen/CodeGenModule.cpp
===================================================================
--- lib/CodeGen/CodeGenModule.cpp
+++ lib/CodeGen/CodeGenModule.cpp
@@ -738,6 +738,9 @@
     B.addAttribute(llvm::Attribute::StackProtectStrong);
   else if (LangOpts.getStackProtector() == LangOptions::SSPReq)
     B.addAttribute(llvm::Attribute::StackProtectReq);
+  else if (LangOpts.getStackProtector() == LangOptions::SSPSafeStack)
+    if (!D->hasAttr<NoSafeStackAttr>())
+      B.addAttribute(llvm::Attribute::SafeStack);
 
   // Add sanitizer attributes if function is not blacklisted.
   if (!isInSanitizerBlacklist(F, D->getLocation())) {
Index: lib/Driver/ToolChains.cpp
===================================================================
--- lib/Driver/ToolChains.cpp
+++ lib/Driver/ToolChains.cpp
@@ -10,6 +10,7 @@
 #include "ToolChains.h"
 #include "clang/Basic/ObjCRuntime.h"
 #include "clang/Basic/Version.h"
+#include "clang/Basic/LangOptions.h"
 #include "clang/Config/config.h" // for GCC_INSTALL_PREFIX
 #include "clang/Driver/Compilation.h"
 #include "clang/Driver/Driver.h"
Index: lib/Driver/Tools.cpp
===================================================================
--- lib/Driver/Tools.cpp
+++ lib/Driver/Tools.cpp
@@ -2172,6 +2172,30 @@
   CmdArgs.push_back(Args.MakeArgString(LibProfile));
 }
 
+static void addSafeStackRT(
+    const ToolChain &TC, const ArgList &Args, ArgStringList &CmdArgs) {
+  if (!Args.hasFlag(options::OPT_fsafe_stack,
+                    options::OPT_fno_safe_stack, false))
+    return;
+
+  const char *LibBaseName = "libclang_rt.safestack-";
+  SmallString<128> LibName = getCompilerRTLibDir(TC);
+  llvm::sys::path::append(LibName,
+      Twine(LibBaseName) + getArchNameForCompilerRTLib(TC) + ".a");
+
+  CmdArgs.push_back(Args.MakeArgString(LibName));
+
+  // Safestack runtime requires dl on Linux
+  if (TC.getTriple().isOSLinux())
+    CmdArgs.push_back("-ldl");
+
+  // We need to ensure that the safe stack init function from the safestack
+  // runtime library is linked in, even though it might not be referenced by
+  // any code in the module before LTO optimizations are applied.
+  CmdArgs.push_back("-u");
+  CmdArgs.push_back("__llvm__safestack_init");
+}
+
 static SmallString<128> getSanitizerRTLibName(const ToolChain &TC,
                                               StringRef Sanitizer,
                                               bool Shared) {
@@ -3675,7 +3699,14 @@
 
   // -stack-protector=0 is default.
   unsigned StackProtectorLevel = 0;
-  if (Arg *A = Args.getLastArg(options::OPT_fno_stack_protector,
+  if (Args.hasFlag(options::OPT_fsafe_stack,
+                   options::OPT_fno_safe_stack, false)) {
+    StackProtectorLevel = LangOptions::SSPSafeStack;
+    Args.ClaimAllArgs(options::OPT_fno_stack_protector);
+    Args.ClaimAllArgs(options::OPT_fstack_protector_all);
+    Args.ClaimAllArgs(options::OPT_fstack_protector_strong);
+    Args.ClaimAllArgs(options::OPT_fstack_protector);
+  } else if (Arg *A = Args.getLastArg(options::OPT_fno_stack_protector,
                                options::OPT_fstack_protector_all,
                                options::OPT_fstack_protector_strong,
                                options::OPT_fstack_protector)) {
@@ -5843,6 +5874,21 @@
       !Args.hasArg(options::OPT_nostartfiles))
     getMachOToolChain().addStartObjectFileArgs(Args, CmdArgs);
 
+  // SafeStack requires its own runtime libraries
+  // These libraries should be linked first, to make sure the
+  // __llvm__safestack_init constructor executes before everything else
+  if (Args.hasFlag(options::OPT_fsafe_stack,
+                   options::OPT_fno_safe_stack, false)) {
+    getMachOToolChain().AddLinkRuntimeLib(Args, CmdArgs,
+                                          "libclang_rt.safestack_osx.a");
+
+    // We need to ensure that the safe stack init function from the safestack
+    // runtime library is linked in, even though it might not be referenced by
+    // any code in the module before LTO optimizations are applied.
+    CmdArgs.push_back("-u");
+    CmdArgs.push_back("___llvm__safestack_init");
+  }
+
   Args.AddAllArgs(CmdArgs, options::OPT_L);
 
   LibOpenMP UsedOpenMPLib = LibUnknown;
@@ -6092,6 +6138,8 @@
 
   CmdArgs.push_back(Args.MakeArgString("-L" + GCCLibPath));
 
+  addSafeStackRT(getToolChain(), Args, CmdArgs);
+
   Args.AddAllArgs(CmdArgs, options::OPT_L);
   Args.AddAllArgs(CmdArgs, options::OPT_T_Group);
   Args.AddAllArgs(CmdArgs, options::OPT_e);
@@ -6638,6 +6686,8 @@
     CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath(crtbegin)));
   }
 
+  addSafeStackRT(getToolChain(), Args, CmdArgs);
+
   Args.AddAllArgs(CmdArgs, options::OPT_L);
   const ToolChain::path_list &Paths = ToolChain.getFilePaths();
   for (const auto &Path : Paths)
@@ -6932,6 +6982,8 @@
     }
   }
 
+  addSafeStackRT(getToolChain(), Args, CmdArgs);
+
   Args.AddAllArgs(CmdArgs, options::OPT_L);
   Args.AddAllArgs(CmdArgs, options::OPT_T_Group);
   Args.AddAllArgs(CmdArgs, options::OPT_e);
@@ -7471,6 +7523,8 @@
     ToolChain.AddFastMathRuntimeIfAvailable(Args, CmdArgs);
   }
 
+  addSafeStackRT(getToolChain(), Args, CmdArgs);
+
   Args.AddAllArgs(CmdArgs, options::OPT_L);
   Args.AddAllArgs(CmdArgs, options::OPT_u);
 
@@ -7613,6 +7667,8 @@
       CmdArgs.push_back(Args.MakeArgString(getToolChain().GetFilePath("crtn.o")));
   }
 
+  addSafeStackRT(getToolChain(), Args, CmdArgs);
+
   Args.AddAllArgs(CmdArgs, options::OPT_L);
   Args.AddAllArgs(CmdArgs, options::OPT_T_Group);
   Args.AddAllArgs(CmdArgs, options::OPT_e);
@@ -7738,6 +7794,8 @@
                               getToolChain().GetFilePath("crtbegin.o")));
   }
 
+  addSafeStackRT(getToolChain(), Args, CmdArgs);
+
   Args.AddAllArgs(CmdArgs, options::OPT_L);
   Args.AddAllArgs(CmdArgs, options::OPT_T_Group);
   Args.AddAllArgs(CmdArgs, options::OPT_e);
Index: lib/Frontend/CompilerInvocation.cpp
===================================================================
--- lib/Frontend/CompilerInvocation.cpp
+++ lib/Frontend/CompilerInvocation.cpp
@@ -1606,6 +1606,7 @@
   case 1: Opts.setStackProtector(LangOptions::SSPOn);  break;
   case 2: Opts.setStackProtector(LangOptions::SSPStrong); break;
   case 3: Opts.setStackProtector(LangOptions::SSPReq); break;
+  case 4: Opts.setStackProtector(LangOptions::SSPSafeStack); break;
   }
 
   // Parse -fsanitize= arguments.
Index: lib/Frontend/InitPreprocessor.cpp
===================================================================
--- lib/Frontend/InitPreprocessor.cpp
+++ lib/Frontend/InitPreprocessor.cpp
@@ -826,6 +826,8 @@
     Builder.defineMacro("__SSP_STRONG__", "2");
   else if (LangOpts.getStackProtector() == LangOptions::SSPReq)
     Builder.defineMacro("__SSP_ALL__", "3");
+  else if (LangOpts.getStackProtector() == LangOptions::SSPSafeStack)
+    Builder.defineMacro("__SAFESTACK__", "4");
 
   if (FEOpts.ProgramAction == frontend::RewriteObjC)
     Builder.defineMacro("__weak", "__attribute__((objc_gc(weak)))");
Index: lib/Sema/SemaDeclAttr.cpp
===================================================================
--- lib/Sema/SemaDeclAttr.cpp
+++ lib/Sema/SemaDeclAttr.cpp
@@ -4593,6 +4593,9 @@
   case AttributeList::AT_ScopedLockable:
     handleSimpleAttribute<ScopedLockableAttr>(S, D, Attr);
     break;
+  case AttributeList::AT_NoSafeStack:
+    handleSimpleAttribute<NoSafeStackAttr>(S, D, Attr);
+    break;
   case AttributeList::AT_NoSanitizeAddress:
     handleSimpleAttribute<NoSanitizeAddressAttr>(S, D, Attr);
     break;
Index: runtime/compiler-rt/Makefile
===================================================================
--- runtime/compiler-rt/Makefile
+++ runtime/compiler-rt/Makefile
@@ -83,7 +83,7 @@
 	eprintf.a 10.4.a osx.a ios.a cc_kext.a cc_kext_ios5.a \
 	asan_osx_dynamic.dylib \
 	profile_osx.a profile_ios.a \
-	ubsan_osx.a
+	ubsan_osx.a safestack_osx.a
 
 RuntimeLibrary.macho_embedded.Configs := \
 	hard_static.a hard_pic.a
@@ -127,7 +127,7 @@
 # We try to build 32-bit runtimes both on 32-bit hosts and 64-bit hosts.
 Runtime32BitConfigs = \
 	builtins-i386.a profile-i386.a san-i386.a asan-i386.a asan_cxx-i386.a \
-	ubsan-i386.a ubsan_cxx-i386.a
+	ubsan-i386.a ubsan_cxx-i386.a safestack-i386.a
 
 # We currently only try to generate runtime libraries on x86.
 ifeq ($(ARCH),x86)
@@ -138,7 +138,7 @@
 RuntimeLibrary.linux.Configs += \
 	builtins-x86_64.a profile-x86_64.a san-x86_64.a asan-x86_64.a \
 	asan_cxx-x86_64.a tsan-x86_64.a msan-x86_64.a ubsan-x86_64.a \
-	ubsan_cxx-x86_64.a dfsan-x86_64.a lsan-x86_64.a
+	ubsan_cxx-x86_64.a dfsan-x86_64.a lsan-x86_64.a safestack-x86_64.a
 # We need to build 32-bit ASan/UBsan libraries on 64-bit platform, and add them
 # to the list of runtime libraries to make
 # "clang -fsanitize=(address|undefined) -m32" work.
Index: test/CodeGen/safestack-attr.cpp
===================================================================
--- /dev/null
+++ test/CodeGen/safestack-attr.cpp
@@ -0,0 +1,6 @@
+// RUN: %clang_cc1 -triple x86_64-linux-unknown -emit-llvm -o - %s -stack-protector 4 | FileCheck -check-prefix=SP %s
+
+__attribute__((no_safe_stack))
+int foo(int *a) {  return *a; }
+
+// SP-NOT: attributes #{{.*}} = { nounwind safestack{{.*}} }
Index: test/CodeGen/stack-protector.c
===================================================================
--- test/CodeGen/stack-protector.c
+++ test/CodeGen/stack-protector.c
@@ -6,6 +6,8 @@
 // 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 {
+// RUN: %clang_cc1 -emit-llvm -o - %s -stack-protector 4 | FileCheck -check-prefix=SAFESTACK %s
+// SAFESTACK: define void @test1(i8* %msg) #0 {
 
 typedef __SIZE_TYPE__ size_t;
 
@@ -26,3 +28,5 @@
 // SSPSTRONG: attributes #{{.*}} = { nounwind sspstrong{{.*}} }
 
 // SSPREQ: attributes #{{.*}} = { nounwind sspreq{{.*}} }
+
+// SAFESTACK: attributes #{{.*}} = { nounwind safestack{{.*}} }
Index: test/Driver/safestack.c
===================================================================
--- /dev/null
+++ test/Driver/safestack.c
@@ -0,0 +1,6 @@
+// RUN: %clang -fno-safe-stack -### %s 2>&1 | FileCheck %s -check-prefix=NOSP
+// NOSP-NOT: "-stack-protector" "4"
+
+// RUN: %clang -fsafe-stack -### %s 2>&1 | FileCheck %s -check-prefix=SP
+// RUN: %clang -fsanatizer=address -fsafe-stack -### %s 2>&1 | FileCheck %s -check-prefix=SP
+// SP: "-stack-protector" "4"
Index: test/SemaCXX/attr-no-safestack.cpp
===================================================================
--- /dev/null
+++ test/SemaCXX/attr-no-safestack.cpp
@@ -0,0 +1,37 @@
+// RUN: %clang_cc1 -fsyntax-only -verify  %s
+
+#define NO_SAFE_STACK __attribute__((no_safe_stack))
+
+#if !__has_attribute(no_safe_stack)
+#error "Should support no_safe_stack"
+#endif
+
+void nosp_fun() NO_SAFE_STACK;
+
+void nosp_fun_args() __attribute__((no_safe_stack(1))); // \
+  // expected-error {{'no_safe_stack' attribute takes no arguments}}
+
+int nosp_testfn(int y) NO_SAFE_STACK;
+
+int nosp_testfn(int y) {
+  int x NO_SAFE_STACK = y; // \
+    // expected-error {{'no_safe_stack' attribute only applies to functions}}
+  return x;
+}
+
+int nosp_test_var NO_SAFE_STACK; // \
+  // expected-error {{'no_safe_stack' attribute only applies to functions}}
+
+class NoSPFoo {
+ private:
+  int test_field NO_SAFE_STACK; // \
+    // expected-error {{'no_safe_stack' attribute only applies to functions}}
+  void test_method() NO_SAFE_STACK;
+};
+
+class NO_SAFE_STACK NoSPTestClass { // \
+  // expected-error {{'no_safe_stack' attribute only applies to functions}}
+};
+
+void nosp_fun_params(int lvar NO_SAFE_STACK); // \
+  // expected-error {{'no_safe_stack' attribute only applies to functions}}
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