Add Forward Control-Flow Integrity.

[oota-llvm.git] / lib / Analysis / JumpInstrTableInfo.cpp

diff --git a/lib/Analysis/JumpInstrTableInfo.cpp b/lib/Analysis/JumpInstrTableInfo.cpp
index b5b426533ff3430432a6dacb7360992dfa15d449..7aae2a5592e96175e4d800b881c777a75050cc3f 100644 (file)
--- a/lib/Analysis/JumpInstrTableInfo.cpp
+++ b/lib/Analysis/JumpInstrTableInfo.cpp
@@ -17,6 +17,7 @@
 #include "llvm/Analysis/Passes.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/Type.h"
+#include "llvm/Support/MathExtras.h"
 
 using namespace llvm;
 
@@ -28,7 +29,21 @@ ImmutablePass *llvm::createJumpInstrTableInfoPass() {
   return new JumpInstrTableInfo();
 }
 
-JumpInstrTableInfo::JumpInstrTableInfo() : ImmutablePass(ID), Tables() {
+ModulePass *llvm::createJumpInstrTableInfoPass(unsigned Bound) {
+  // This cast is always safe, since Bound is always in a subset of uint64_t.
+  uint64_t B = static_cast<uint64_t>(Bound);
+  return new JumpInstrTableInfo(B);
+}
+
+JumpInstrTableInfo::JumpInstrTableInfo(uint64_t ByteAlign)
+    : ImmutablePass(ID), Tables(), ByteAlignment(ByteAlign) {
+  if (!llvm::isPowerOf2_64(ByteAlign)) {
+    // Note that we don't explicitly handle overflow here, since we handle the 0
+    // case explicitly when a caller actually tries to create jumptable entries,
+    // and this is the return value on overflow.
+    ByteAlignment = llvm::NextPowerOf2(ByteAlign);
+  }
+
   initializeJumpInstrTableInfoPass(*PassRegistry::getPassRegistry());
 }