diff --git a/clang/test/Frontend/stack-usage-safestack.c b/clang/test/Frontend/stack-usage-safestack.c
new file mode 100644
--- /dev/null
+++ b/clang/test/Frontend/stack-usage-safestack.c
@@ -0,0 +1,20 @@
+/// Check that stack frame size warnings behave the same when safe stack is enabled
+
+// RUN: %clang_cc1 %s -fwarn-stack-size=48 -S -o - -triple=i386-apple-darwin 2>&1 | FileCheck --check-prefix=REGULAR %s
+// RUN: %clang_cc1 %s -fwarn-stack-size=1060 -S -o - -triple=i386-apple-darwin 2>&1 | FileCheck --check-prefix=IGNORE %s
+
+// RUN: %clang_cc1 %s -fsanitize=safe-stack -fwarn-stack-size=48 -S -o - -triple=i386-apple-darwin 2>&1 | FileCheck --check-prefix=SAFESTACK %s
+// RUN: %clang_cc1 %s -fsanitize=safe-stack -fwarn-stack-size=1060 -S -o - -triple=i386-apple-darwin 2>&1 | FileCheck --check-prefix=IGNORE %s
+
+extern void init(int *buf, int size);
+extern int use_buf(int *buf, int size);
+
+// REGULAR: warning: stack frame size ([[#]]) exceeds limit ([[#]]) in 'stackSizeWarning'
+// SAFESTACK: warning: stack frame size ([[#]]) exceeds limit ([[#]]) in 'stackSizeWarning'
+// IGNORE-NOT: stack frame size ([[#]]) exceeds limit ([[#]]) in 'stackSizeWarning'
+void stackSizeWarning() {
+  int buf[256];
+  init(buf, sizeof(buf));
+  if (buf[0] < 42)
+    use_buf(buf, sizeof(buf));
+}
diff --git a/llvm/include/llvm/CodeGen/MachineFrameInfo.h b/llvm/include/llvm/CodeGen/MachineFrameInfo.h
--- a/llvm/include/llvm/CodeGen/MachineFrameInfo.h
+++ b/llvm/include/llvm/CodeGen/MachineFrameInfo.h
@@ -335,6 +335,9 @@
   /// Not null, if shrink-wrapping found a better place for the epilogue.
   MachineBasicBlock *Restore = nullptr;
 
+  /// Size of the UnsafeStack Frame
+  uint64_t UnsafeStackSize = 0;
+
 public:
   explicit MachineFrameInfo(unsigned StackAlignment, bool StackRealignable,
                             bool ForcedRealign)
@@ -773,6 +776,9 @@
   MachineBasicBlock *getRestorePoint() const { return Restore; }
   void setRestorePoint(MachineBasicBlock *NewRestore) { Restore = NewRestore; }
 
+  uint64_t getUnsafeStackSize() const { return UnsafeStackSize; }
+  void setUnsafeStackSize(uint64_t Size) { UnsafeStackSize = Size; }
+
   /// Return a set of physical registers that are pristine.
   ///
   /// Pristine registers hold a value that is useless to the current function,
diff --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
--- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -1208,7 +1208,8 @@
     return;
 
   const MachineFrameInfo &FrameInfo = MF.getFrameInfo();
-  uint64_t StackSize = FrameInfo.getStackSize();
+  uint64_t StackSize =
+      FrameInfo.getStackSize() + FrameInfo.getUnsafeStackSize();
 
   if (StackUsageStream == nullptr) {
     std::error_code EC;
diff --git a/llvm/lib/CodeGen/MachineFunction.cpp b/llvm/lib/CodeGen/MachineFunction.cpp
--- a/llvm/lib/CodeGen/MachineFunction.cpp
+++ b/llvm/lib/CodeGen/MachineFunction.cpp
@@ -109,6 +109,27 @@
   llvm_unreachable("Invalid machine function property");
 }
 
+void setUnsafeStackSize(const Function &F, MachineFrameInfo &FrameInfo) {
+  if (!F.hasFnAttribute(Attribute::SafeStack))
+    return;
+
+  auto *Existing =
+      dyn_cast_or_null<MDTuple>(F.getMetadata(LLVMContext::MD_annotation));
+
+  if (!Existing || Existing->getNumOperands() != 2)
+    return;
+
+  auto *MetadataName = "unsafe-stack-size";
+  if (auto &N = Existing->getOperand(0)) {
+    if (cast<MDString>(N.get())->getString() == MetadataName) {
+      if (auto &Op = Existing->getOperand(1)) {
+        auto Val = mdconst::extract<ConstantInt>(Op)->getZExtValue();
+        FrameInfo.setUnsafeStackSize(Val);
+      }
+    }
+  }
+}
+
 // Pin the vtable to this file.
 void MachineFunction::Delegate::anchor() {}
 
@@ -177,6 +198,8 @@
       /*ForcedRealign=*/CanRealignSP &&
           F.hasFnAttribute(Attribute::StackAlignment));
 
+  setUnsafeStackSize(F, *FrameInfo);
+
   if (F.hasFnAttribute(Attribute::StackAlignment))
     FrameInfo->ensureMaxAlignment(*F.getFnStackAlign());
 
diff --git a/llvm/lib/CodeGen/PrologEpilogInserter.cpp b/llvm/lib/CodeGen/PrologEpilogInserter.cpp
--- a/llvm/lib/CodeGen/PrologEpilogInserter.cpp
+++ b/llvm/lib/CodeGen/PrologEpilogInserter.cpp
@@ -285,6 +285,9 @@
     assert(!Failed && "Invalid warn-stack-size fn attr value");
     (void)Failed;
   }
+  if (MF.getFunction().hasFnAttribute(Attribute::SafeStack)) {
+    StackSize += MFI.getUnsafeStackSize();
+  }
   if (StackSize > Threshold) {
     DiagnosticInfoStackSize DiagStackSize(F, StackSize, Threshold, DS_Warning);
     F.getContext().diagnose(DiagStackSize);
diff --git a/llvm/lib/CodeGen/SafeStack.cpp b/llvm/lib/CodeGen/SafeStack.cpp
--- a/llvm/lib/CodeGen/SafeStack.cpp
+++ b/llvm/lib/CodeGen/SafeStack.cpp
@@ -49,6 +49,7 @@
 #include "llvm/IR/IntrinsicInst.h"
 #include "llvm/IR/Intrinsics.h"
 #include "llvm/IR/MDBuilder.h"
+#include "llvm/IR/Metadata.h"
 #include "llvm/IR/Module.h"
 #include "llvm/IR/Type.h"
 #include "llvm/IR/Use.h"
@@ -645,6 +646,13 @@
   // FIXME: no need to update BasePointer in leaf functions.
   unsigned FrameSize = alignTo(SSL.getFrameSize(), StackAlignment);
 
+  MDBuilder MDB(F.getContext());
+  SmallVector<Metadata *, 2> Data;
+  Data.push_back(MDB.createString("unsafe-stack-size"));
+  Data.push_back(MDB.createConstant(ConstantInt::get(Int32Ty, FrameSize)));
+  MDNode *MD = MDTuple::get(F.getContext(), Data);
+  F.setMetadata(LLVMContext::MD_annotation, MD);
+
   // Update shadow stack pointer in the function epilogue.
   IRB.SetInsertPoint(BasePointer->getNextNode());