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

1 files changed, 11 insertions, 0 deletions

diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 05e5196e32d..849e3ba9f27 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -2829,6 +2829,17 @@ static void ParsePreprocessorArgs(PreprocessorOptions &Opts, ArgList &Args,
     }
   }
 
+  // Add the __CET__ macro if a CFProtection option is set.
+  if (const Arg *A = Args.getLastArg(OPT_fcf_protection_EQ)) {
+    StringRef Name = A->getValue();
+    if (Name == "branch")
+      Opts.addMacroDef("__CET__=1");
+    else if (Name == "return")
+      Opts.addMacroDef("__CET__=2");
+    else if (Name == "full")
+      Opts.addMacroDef("__CET__=3");
+  }
+
   // Add macros from the command line.
   for (const auto *A : Args.filtered(OPT_D, OPT_U)) {
     if (A->getOption().matches(OPT_D))