3 files changed, 42 insertions, 2 deletions
diff --git a/lib/CodeGen/StackProtector.cpp b/lib/CodeGen/StackProtector.cpp
index 8a6a727a1f..e318afe2b5 100644
--- a/lib/CodeGen/StackProtector.cpp
+++ b/lib/CodeGen/StackProtector.cpp
@@ -136,7 +136,7 @@ bool StackProtector::RequiresStackProtector() const {
 bool StackProtector::InsertStackProtectors() {
   BasicBlock *FailBB = 0;       // The basic block to jump to if check fails.
   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++;
@@ -155,7 +155,20 @@ bool StackProtector::InsertStackProtectors() {
       // 
       PointerType *PtrTy = PointerType::getUnqual(
           Type::getInt8Ty(RI->getContext()));
-      StackGuardVar = M->getOrInsertGlobal("__stack_chk_guard", PtrTy);
+
+      unsigned AddressSpace, Offset;
+      if (TLI->getStackCookieLocation(AddressSpace, Offset)) {
+        Constant *ASPtr = Constant::getNullValue(
+            PointerType::get(Type::getInt8Ty(RI->getContext()), AddressSpace));
+        APInt OffsetInt(32, Offset);
+        Constant *OffsetVal = Constant::getIntegerValue(
+            Type::getInt32Ty(RI->getContext()), OffsetInt);
+        StackGuardVar = ConstantExpr::getPointerCast(
+            ConstantExpr::getGetElementPtr(ASPtr, &OffsetVal, 1),
+            PointerType::get(PtrTy, AddressSpace));
+      } else {
+          StackGuardVar = M->getOrInsertGlobal("__stack_chk_guard", PtrTy); 
+      }
 
       BasicBlock &Entry = F->getEntryBlock();
       Instruction *InsPt = &Entry.front();
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 423a076e7d..8a0a04ee22 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -1189,6 +1189,27 @@ unsigned X86TargetLowering::getFunctionAlignment(const Function *F) const {
   return F->hasFnAttr(Attribute::OptimizeForSize) ? 0 : 4;
 }
 
+bool X86TargetLowering::getStackCookieLocation(unsigned &AddressSpace,
+                                               unsigned &Offset) const {
+  if (!Subtarget->isTargetLinux())
+    return false;
+
+  if (Subtarget->is64Bit()) {
+    // %fs:0x28, unless we're using a Kernel code model, in which case it's %gs:
+    Offset = 0x28;
+    if (getTargetMachine().getCodeModel() == CodeModel::Kernel)
+      AddressSpace = 256;
+    else
+      AddressSpace = 257;
+  } else {
+    // %gs:0x14 on i386
+    Offset = 0x14;
+    AddressSpace = 256;
+  }
+  return true;
+}
+
+
 //===----------------------------------------------------------------------===//
 //               Return Value Calling Convention Implementation
 //===----------------------------------------------------------------------===//
diff --git a/lib/Target/X86/X86ISelLowering.h b/lib/Target/X86/X86ISelLowering.h
index a7de0b1166..82cef27a63 100644
--- a/lib/Target/X86/X86ISelLowering.h
+++ b/lib/Target/X86/X86ISelLowering.h
@@ -593,6 +593,12 @@ namespace llvm {
     /// getFunctionAlignment - Return the Log2 alignment of this function.
     virtual unsigned getFunctionAlignment(const Function *F) const;
 
+    /// getStackCookieLocation - Return true if the target stores stack
+    /// protector cookies at a fixed offset in some non-standard address
+    /// space, and populates the address space and offset as
+    /// appropriate.
+    virtual bool getStackCookieLocation(unsigned &AddressSpace, unsigned &Offset) const;
+
   private:
     /// Subtarget - Keep a pointer to the X86Subtarget around so that we can
     /// make the right decision when generating code for different targets.