Add Windows Control Flow Guard checks (/guard:cf).

Summary:
A new function pass (Transforms/CFGuard/CFGuard.cpp) inserts CFGuard checks on
indirect function calls, using either the check mechanism (X86, ARM, AArch64) or
or the dispatch mechanism (X86-64). The check mechanism requires a new calling
convention for the supported targets. The dispatch mechanism adds the target as
an operand bundle, which is processed by SelectionDAG. Another pass
(CodeGen/CFGuardLongjmp.cpp) identifies and emits valid longjmp targets, as
required by /guard:cf. This feature is enabled using the `cfguard` CC1 option.

Reviewers: thakis, rnk, theraven, pcc

Subscribers: ychen, hans, metalcanine, dmajor, tomrittervg, alex, mehdi_amini, mgorny, javed.absar, kristof.beyls, hiraditya, steven_wu, dexonsmith, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D65761

1 files changed, 9 insertions, 0 deletions

diff --git a/llvm/lib/Target/ARM/ARMTargetMachine.cpp b/llvm/lib/Target/ARM/ARMTargetMachine.cpp
index 5c8007f101d..7f85b93beac 100644
--- a/llvm/lib/Target/ARM/ARMTargetMachine.cpp
+++ b/llvm/lib/Target/ARM/ARMTargetMachine.cpp
@@ -46,6 +46,7 @@
 #include "llvm/Support/TargetRegistry.h"
 #include "llvm/Target/TargetLoweringObjectFile.h"
 #include "llvm/Target/TargetOptions.h"
+#include "llvm/Transforms/CFGuard.h"
 #include "llvm/Transforms/Scalar.h"
 #include <cassert>
 #include <memory>
@@ -420,6 +421,10 @@ void ARMPassConfig::addIRPasses() {
   // Match interleaved memory accesses to ldN/stN intrinsics.
   if (TM->getOptLevel() != CodeGenOpt::None)
     addPass(createInterleavedAccessPass());
+
+  // Add Control Flow Guard checks.
+  if (TM->getTargetTriple().isOSWindows())
+    addPass(createCFGuardCheckPass());
 }
 
 void ARMPassConfig::addCodeGenPrepare() {
@@ -534,4 +539,8 @@ void ARMPassConfig::addPreEmitPass() {
 
   addPass(createARMConstantIslandPass());
   addPass(createARMLowOverheadLoopsPass());
+
+  // Identify valid longjmp targets for Windows Control Flow Guard.
+  if (TM->getTargetTriple().isOSWindows())
+    addPass(createCFGuardLongjmpPass());
 }