+/// ContainsProtectableArray - Check whether the type either is an array or
+/// contains a char array of sufficient size so that we need stack protectors
+/// for it.
+bool StackProtector::ContainsProtectableArray(Type *Ty, bool InStruct) const {
+ if (!Ty) return false;
+ if (ArrayType *AT = dyn_cast<ArrayType>(Ty)) {
+ const TargetMachine &TM = TLI->getTargetMachine();
+ if (!AT->getElementType()->isIntegerTy(8)) {
+ Triple Trip(TM.getTargetTriple());
+
+ // If we're on a non-Darwin platform or we're inside of a structure, don't
+ // add stack protectors unless the array is a character array.
+ if (InStruct || !Trip.isOSDarwin())
+ return false;
+ }
+
+ // If an array has more than SSPBufferSize bytes of allocated space, then we
+ // emit stack protectors.
+ if (TM.Options.SSPBufferSize <= TLI->getDataLayout()->getTypeAllocSize(AT))
+ return true;
+ }
+
+ const StructType *ST = dyn_cast<StructType>(Ty);
+ if (!ST) return false;
+
+ for (StructType::element_iterator I = ST->element_begin(),
+ E = ST->element_end(); I != E; ++I)
+ if (ContainsProtectableArray(*I, true))
+ return true;
+
+ return false;
+}
+
+/// RequiresStackProtector - Check whether or not this function needs a stack
+/// protector based upon the stack protector level. The heuristic we use is to
+/// add a guard variable to functions that call alloca, and functions with
+/// buffers larger than SSPBufferSize bytes.
+bool StackProtector::RequiresStackProtector() const {
+ if (F->getFnAttributes().hasAttribute(Attributes::StackProtectReq))
+ return true;
+
+ if (!F->getFnAttributes().hasAttribute(Attributes::StackProtect))
+ return false;
+
+ for (Function::iterator I = F->begin(), E = F->end(); I != E; ++I) {
+ BasicBlock *BB = I;
+
+ for (BasicBlock::iterator
+ II = BB->begin(), IE = BB->end(); II != IE; ++II)
+ if (AllocaInst *AI = dyn_cast<AllocaInst>(II)) {
+ if (AI->isArrayAllocation())
+ // This is a call to alloca with a variable size. Emit stack
+ // protectors.
+ return true;
+
+ if (ContainsProtectableArray(AI->getAllocatedType()))
+ return true;
+ }
+ }
+
+ return false;
+}
+