X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FStackProtector.cpp;h=f0a44abaf5cda1b4d4267752a46fc73f18a2a492;hb=2b33f4cbad43dcaca944d02a6ea67991ff9db9cf;hp=c333acd42a8b543e2ba23f33a266b16ef4a5d568;hpb=5601699d7c36b819179a7d89270100c34b3d0a32;p=oota-llvm.git

diff --git a/lib/CodeGen/StackProtector.cpp b/lib/CodeGen/StackProtector.cpp
index c333acd42a8..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"
@@ -37,7 +38,7 @@ SSPBufferSize("stack-protector-buffer-size", cl::init(8),
                        "stack protection"));
 
 namespace {
-  class VISIBILITY_HIDDEN StackProtector : public FunctionPass {
+  class StackProtector : public FunctionPass {
     /// TLI - Keep a pointer of a TargetLowering to consult for determining
     /// target type sizes.
     const TargetLowering *TLI;
@@ -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;
   
@@ -111,11 +123,16 @@ bool StackProtector::RequiresStackProtector() const {
           // protectors.
           return true;
 
-        if (const ArrayType *AT = dyn_cast<ArrayType>(AI->getAllocatedType()))
+        if (const ArrayType *AT = dyn_cast<ArrayType>(AI->getAllocatedType())) {
+          // We apparently only care about character arrays.
+          if (!AT->getElementType()->isIntegerTy(8))
+            continue;
+
           // If an array has more than SSPBufferSize bytes of allocated space,
           // then we emit stack protectors.
-          if (SSPBufferSize <= TD->getTypePaddedSize(AT))
+          if (SSPBufferSize <= TD->getTypeAllocSize(AT))
             return true;
+        }
       }
   }
 
@@ -130,12 +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.
-  Constant *StackGuardVar = 0;  // The stack guard variable.
+  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;
 
@@ -148,8 +165,17 @@ bool StackProtector::InsertStackProtectors() {
       //     StackGuard = load __stack_chk_guard
       //     call void @llvm.stackprotect.create(StackGuard, StackGuardSlot)
       // 
-      PointerType *PtrTy = PointerType::getUnqual(Type::Int8Ty);
-      StackGuardVar = M->getOrInsertGlobal("__stack_chk_guard", PtrTy);
+      const PointerType *PtrTy = Type::getInt8PtrTy(RI->getContext());
+      unsigned AddressSpace, Offset;
+      if (TLI->getStackCookieLocation(AddressSpace, Offset)) {
+        Constant *OffsetVal =
+          ConstantInt::get(Type::getInt32Ty(RI->getContext()), Offset);
+        
+        StackGuardVar = ConstantExpr::getIntToPtr(OffsetVal,
+                                      PointerType::get(PtrTy, AddressSpace));
+      } else {
+        StackGuardVar = M->getOrInsertGlobal("__stack_chk_guard", PtrTy); 
+      }
 
       BasicBlock &Entry = F->getEntryBlock();
       Instruction *InsPt = &Entry.front();
@@ -191,6 +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();
 
@@ -201,7 +232,7 @@ bool StackProtector::InsertStackProtectors() {
     // Generate the stack protector instructions in the old basic block.
     LoadInst *LI1 = new LoadInst(StackGuardVar, "", false, BB);
     LoadInst *LI2 = new LoadInst(AI, "", true, BB);
-    ICmpInst *Cmp = new ICmpInst(CmpInst::ICMP_EQ, LI1, LI2, "", BB);
+    ICmpInst *Cmp = new ICmpInst(*BB, CmpInst::ICMP_EQ, LI1, LI2, "");
     BranchInst::Create(NewBB, FailBB, Cmp, BB);
   }
 
@@ -209,16 +240,21 @@ bool StackProtector::InsertStackProtectors() {
   // statements in the function.
   if (!FailBB) return false;
 
+  if (DT && FailBBDom)
+    DT->addNewBlock(FailBB, FailBBDom);
+
   return true;
 }
 
 /// CreateFailBB - Create a basic block to jump to when the stack protector
 /// check fails.
 BasicBlock *StackProtector::CreateFailBB() {
-  BasicBlock *FailBB = BasicBlock::Create("CallStackCheckFailBlk", F);
+  BasicBlock *FailBB = BasicBlock::Create(F->getContext(),
+                                          "CallStackCheckFailBlk", F);
   Constant *StackChkFail =
-    M->getOrInsertFunction("__stack_chk_fail", Type::VoidTy, NULL);
+    M->getOrInsertFunction("__stack_chk_fail",
+                           Type::getVoidTy(F->getContext()), NULL);
   CallInst::Create(StackChkFail, "", FailBB);
-  new UnreachableInst(FailBB);
+  new UnreachableInst(F->getContext(), FailBB);
   return FailBB;
 }