X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FStackProtector.cpp;h=f0a44abaf5cda1b4d4267752a46fc73f18a2a492;hb=2b33f4cbad43dcaca944d02a6ea67991ff9db9cf;hp=ca5c28ce010cb29d3fe16759fe515dc8d53e2fd9;hpb=f8bd392dce26226249b99bc1fa8d112602da3e63;p=oota-llvm.git

diff --git a/lib/CodeGen/StackProtector.cpp b/lib/CodeGen/StackProtector.cpp
index ca5c28ce010..f0a44abaf5c 100644
--- a/lib/CodeGen/StackProtector.cpp
+++ b/lib/CodeGen/StackProtector.cpp
@@ -16,6 +16,7 @@
 
 #define DEBUG_TYPE "stack-protector"
 #include "llvm/CodeGen/Passes.h"
+#include "llvm/Analysis/Dominators.h"
 #include "llvm/Attributes.h"
 #include "llvm/Constants.h"
 #include "llvm/DerivedTypes.h"
@@ -45,6 +46,8 @@ namespace {
     Function *F;
     Module *M;
 
+    DominatorTree* DT;
+
     /// InsertStackProtectors - Insert code into the prologue and epilogue of
     /// the function.
     ///
@@ -62,17 +65,25 @@ namespace {
     bool RequiresStackProtector() const;
   public:
     static char ID;             // Pass identification, replacement for typeid.
-    StackProtector() : FunctionPass(&ID), TLI(0) {}
+    StackProtector() : FunctionPass(ID), TLI(0) {
+      initializeStackProtectorPass(*PassRegistry::getPassRegistry());
+    }
     StackProtector(const TargetLowering *tli)
-      : FunctionPass(&ID), TLI(tli) {}
+      : FunctionPass(ID), TLI(tli) {
+        initializeStackProtectorPass(*PassRegistry::getPassRegistry());
+      }
+
+    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+      AU.addPreserved<DominatorTree>();
+    }
 
     virtual bool runOnFunction(Function &Fn);
   };
 } // end anonymous namespace
 
 char StackProtector::ID = 0;
-static RegisterPass<StackProtector>
-X("stack-protector", "Insert stack protectors");
+INITIALIZE_PASS(StackProtector, "stack-protector",
+                "Insert stack protectors", false, false)
 
 FunctionPass *llvm::createStackProtectorPass(const TargetLowering *tli) {
   return new StackProtector(tli);
@@ -81,6 +92,7 @@ FunctionPass *llvm::createStackProtectorPass(const TargetLowering *tli) {
 bool StackProtector::runOnFunction(Function &Fn) {
   F = &Fn;
   M = F->getParent();
+  DT = getAnalysisIfAvailable<DominatorTree>();
 
   if (!RequiresStackProtector()) return false;
   
@@ -135,12 +147,12 @@ bool StackProtector::RequiresStackProtector() const {
 ///    value. It calls __stack_chk_fail if they differ.
 bool StackProtector::InsertStackProtectors() {
   BasicBlock *FailBB = 0;       // The basic block to jump to if check fails.
+  BasicBlock *FailBBDom = 0;    // FailBB's dominator.
   AllocaInst *AI = 0;           // Place on stack that stores the stack guard.
   Value *StackGuardVar = 0;  // The stack guard variable.
 
   for (Function::iterator I = F->begin(), E = F->end(); I != E; ) {
     BasicBlock *BB = I++;
-
     ReturnInst *RI = dyn_cast<ReturnInst>(BB->getTerminator());
     if (!RI) continue;
 
@@ -205,6 +217,11 @@ bool StackProtector::InsertStackProtectors() {
     // Split the basic block before the return instruction.
     BasicBlock *NewBB = BB->splitBasicBlock(RI, "SP_return");
 
+    if (DT && DT->isReachableFromEntry(BB)) {
+      DT->addNewBlock(NewBB, BB);
+      FailBBDom = FailBBDom ? DT->findNearestCommonDominator(FailBBDom, BB) :BB;
+    }
+
     // Remove default branch instruction to the new BB.
     BB->getTerminator()->eraseFromParent();
 
@@ -223,6 +240,9 @@ bool StackProtector::InsertStackProtectors() {
   // statements in the function.
   if (!FailBB) return false;
 
+  if (DT && FailBBDom)
+    DT->addNewBlock(FailBB, FailBBDom);
+
   return true;
 }