Added Control Flow Protection Flag

Cf-protection is a target independent flag that instructs the back-end to instrument control flow mechanisms like: Branch, Return, etc.
For example in X86 this flag will be used to instrument Indirect Branch Tracking instructions.

Differential Revision: https://reviews.llvm.org/D40478

Change-Id: I5126e766c0e6b84118cae0ee8a20fe78cc373dea
llvm-svn: 322063

2 files changed, 26 insertions, 0 deletions

diff --git a/clang/lib/Basic/Targets/X86.cpp b/clang/lib/Basic/Targets/X86.cpp
index 5d4dfcb8441..268b3590117 100644
--- a/clang/lib/Basic/Targets/X86.cpp
+++ b/clang/lib/Basic/Targets/X86.cpp
@@ -101,6 +101,26 @@ 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 {
diff --git a/clang/lib/Basic/Targets/X86.h b/clang/lib/Basic/Targets/X86.h
index 58b7a09c9ab..290d3db3504 100644
--- a/clang/lib/Basic/Targets/X86.h
+++ b/clang/lib/Basic/Targets/X86.h
@@ -158,6 +158,12 @@ public:
 
   bool validateInputSize(StringRef Constraint, unsigned Size) const override;
 
+  virtual bool
+  checkCFProtectionReturnSupported(DiagnosticsEngine &Diags) const override;
+
+  virtual bool
+  checkCFProtectionBranchSupported(DiagnosticsEngine &Diags) const override;
+
   virtual bool validateOperandSize(StringRef Constraint, unsigned Size) const;
 
   std::string convertConstraint(const char *&Constraint) const override;