This patch aims to match the changes introduced

in gcc by https://gcc.gnu.org/ml/gcc-cvs/2018-04/msg00534.html.
The -mibt feature flag is being removed, and the -fcf-protection
option now also defines a CET macro and causes errors when used
on non-X86 targets, while X86 targets no longer check for -mibt
and -mshstk to determine if -fcf-protection is supported. -mshstk
is now used only to determine availability of shadow stack intrinsics.

Comes with an LLVM patch (D46882).

Patch by mike.dvoretsky

Differential Revision: https://reviews.llvm.org/D46881

llvm-svn: 332704

2 files changed, 7 insertions, 28 deletions

diff --git a/clang/lib/Basic/Targets/X86.cpp b/clang/lib/Basic/Targets/X86.cpp
index 41c4179ec64..1f8de5b599b 100644
--- a/clang/lib/Basic/Targets/X86.cpp
+++ b/clang/lib/Basic/Targets/X86.cpp
@@ -102,26 +102,6 @@ bool X86TargetInfo::setFPMath(StringRef Name) {
   return false;
 }
 
-bool X86TargetInfo::checkCFProtectionReturnSupported(
-    DiagnosticsEngine &Diags) const {
-  if (HasSHSTK)
-    return true;
-
-  Diags.Report(diag::err_opt_not_valid_without_opt) << "cf-protection=return"
-                                                    << "-mshstk";
-  return false;
-}
-
-bool X86TargetInfo::checkCFProtectionBranchSupported(
-    DiagnosticsEngine &Diags) const {
-  if (HasIBT)
-    return true;
-
-  Diags.Report(diag::err_opt_not_valid_without_opt) << "cf-protection=branch"
-                                                    << "-mibt";
-  return false;
-}
-
 bool X86TargetInfo::initFeatureMap(
     llvm::StringMap<bool> &Features, DiagnosticsEngine &Diags, StringRef CPU,
     const std::vector<std::string> &FeaturesVec) const {
@@ -781,8 +761,6 @@ bool X86TargetInfo::handleTargetFeatures(std::vector<std::string> &Features,
       HasMPX = true;
     } else if (Feature == "+shstk") {
       HasSHSTK = true;
-    } else if (Feature == "+ibt") {
-      HasIBT = true;
     } else if (Feature == "+movbe") {
       HasMOVBE = true;
     } else if (Feature == "+sgx") {
@@ -1175,8 +1153,6 @@ void X86TargetInfo::getTargetDefines(const LangOptions &Opts,
     Builder.defineMacro("__MPX__");
   if (HasSHSTK)
     Builder.defineMacro("__SHSTK__");
-  if (HasIBT)
-    Builder.defineMacro("__IBT__");
   if (HasSGX)
     Builder.defineMacro("__SGX__");
   if (HasPREFETCHWT1)
@@ -1394,7 +1370,6 @@ bool X86TargetInfo::hasFeature(StringRef Feature) const {
       .Case("fsgsbase", HasFSGSBASE)
       .Case("fxsr", HasFXSR)
       .Case("gfni", HasGFNI)
-      .Case("ibt", HasIBT)
       .Case("lwp", HasLWP)
       .Case("lzcnt", HasLZCNT)
       .Case("mm3dnow", MMX3DNowLevel >= AMD3DNow)
diff --git a/clang/lib/Basic/Targets/X86.h b/clang/lib/Basic/Targets/X86.h
index c995ec1f61f..2db115cd11e 100644
--- a/clang/lib/Basic/Targets/X86.h
+++ b/clang/lib/Basic/Targets/X86.h
@@ -81,7 +81,6 @@ class LLVM_LIBRARY_VISIBILITY X86TargetInfo : public TargetInfo {
   bool HasSHA = false;
   bool HasMPX = false;
   bool HasSHSTK = false;
-  bool HasIBT = false;
   bool HasSGX = false;
   bool HasCX16 = false;
   bool HasFXSR = false;
@@ -171,10 +170,15 @@ public:
   bool validateInputSize(StringRef Constraint, unsigned Size) const override;
 
   virtual bool
-  checkCFProtectionReturnSupported(DiagnosticsEngine &Diags) const override;
+  checkCFProtectionReturnSupported(DiagnosticsEngine &Diags) const override {
+    return true;
+  };
 
   virtual bool
-  checkCFProtectionBranchSupported(DiagnosticsEngine &Diags) const override;
+  checkCFProtectionBranchSupported(DiagnosticsEngine &Diags) const override {
+    return true;
+  };
+
 
   virtual bool validateOperandSize(StringRef Constraint, unsigned Size) const;