1 files changed, 49 insertions, 21 deletions

diff --git a/lib/CodeGen/StackProtector.cpp b/lib/CodeGen/StackProtector.cpp
index 43a6ad8c97..a04ac3fbc1 100644
--- a/lib/CodeGen/StackProtector.cpp
+++ b/lib/CodeGen/StackProtector.cpp
@@ -28,15 +28,10 @@
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Target/TargetData.h"
 #include "llvm/Target/TargetLowering.h"
+#include "llvm/Target/TargetOptions.h"
+#include "llvm/ADT/Triple.h"
 using namespace llvm;
 
-// SSPBufferSize - The lower bound for a buffer to be considered for stack
-// smashing protection.
-static cl::opt<unsigned>
-SSPBufferSize("stack-protector-buffer-size", cl::init(8),
-              cl::desc("Lower bound for a buffer to be considered for "
-                       "stack protection"));
-
 namespace {
   class StackProtector : public FunctionPass {
     /// TLI - Keep a pointer of a TargetLowering to consult for determining
@@ -46,7 +41,7 @@ namespace {
     Function *F;
     Module *M;
 
-    DominatorTree* DT;
+    DominatorTree *DT;
 
     /// InsertStackProtectors - Insert code into the prologue and epilogue of
     /// the function.
@@ -60,6 +55,11 @@ namespace {
     /// check fails.
     BasicBlock *CreateFailBB();
 
+    /// ContainsProtectableArray - Check whether the type either is an array or
+    /// contains an array of sufficient size so that we need stack protectors
+    /// for it.
+    bool ContainsProtectableArray(Type *Ty, bool InStruct = false) const;
+
     /// RequiresStackProtector - Check whether or not this function needs a
     /// stack protector based upon the stack protector level.
     bool RequiresStackProtector() const;
@@ -70,8 +70,8 @@ namespace {
     }
     StackProtector(const TargetLowering *tli)
       : FunctionPass(ID), TLI(tli) {
-        initializeStackProtectorPass(*PassRegistry::getPassRegistry());
-      }
+      initializeStackProtectorPass(*PassRegistry::getPassRegistry());
+    }
 
     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
       AU.addPreserved<DominatorTree>();
@@ -95,10 +95,43 @@ bool StackProtector::runOnFunction(Function &Fn) {
   DT = getAnalysisIfAvailable<DominatorTree>();
 
   if (!RequiresStackProtector()) return false;
-  
+
   return InsertStackProtectors();
 }
 
+/// 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->getTargetData()->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
@@ -110,8 +143,6 @@ bool StackProtector::RequiresStackProtector() const {
   if (!F->hasFnAttr(Attribute::StackProtect))
     return false;
 
-  const TargetData *TD = TLI->getTargetData();
-
   for (Function::iterator I = F->begin(), E = F->end(); I != E; ++I) {
     BasicBlock *BB = I;
 
@@ -123,11 +154,8 @@ bool StackProtector::RequiresStackProtector() const {
           // protectors.
           return true;
 
-        if (ArrayType *AT = dyn_cast<ArrayType>(AI->getAllocatedType()))
-          // If an array has more than SSPBufferSize bytes of allocated space,
-          // then we emit stack protectors.
-          if (SSPBufferSize <= TD->getTypeAllocSize(AT))
-            return true;
+        if (ContainsProtectableArray(AI->getAllocatedType()))
+          return true;
       }
   }
 
@@ -159,17 +187,17 @@ bool StackProtector::InsertStackProtectors() {
       //     StackGuardSlot = alloca i8*
       //     StackGuard = load __stack_chk_guard
       //     call void @llvm.stackprotect.create(StackGuard, StackGuardSlot)
-      // 
+      //
       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); 
+        StackGuardVar = M->getOrInsertGlobal("__stack_chk_guard", PtrTy);
       }
 
       BasicBlock &Entry = F->getEntryBlock();