diff --git a/clang/include/clang/Basic/DiagnosticFrontendKinds.td b/clang/include/clang/Basic/DiagnosticFrontendKinds.td
--- a/clang/include/clang/Basic/DiagnosticFrontendKinds.td
+++ b/clang/include/clang/Basic/DiagnosticFrontendKinds.td
@@ -26,7 +26,7 @@
 def warn_fe_linking_module : Warning<"linking module '%0': %1">, InGroup<LinkerWarnings>;
 def note_fe_linking_module : Note<"linking module '%0': %1">;
 
-def warn_fe_frame_larger_than : Warning<"stack frame size (%0) exceeds limit (%1) in %q2">,
+def warn_fe_frame_larger_than : Warning<"stack frame size (%0) exceeds limit (%1) in '%2'">,
     BackendInfo, InGroup<BackendFrameLargerThan>;
 def warn_fe_backend_frame_larger_than: Warning<"%0">,
     BackendInfo, InGroup<BackendFrameLargerThan>;
diff --git a/clang/lib/CodeGen/CodeGenAction.cpp b/clang/lib/CodeGen/CodeGenAction.cpp
--- a/clang/lib/CodeGen/CodeGenAction.cpp
+++ b/clang/lib/CodeGen/CodeGenAction.cpp
@@ -25,6 +25,7 @@
 #include "clang/Frontend/CompilerInstance.h"
 #include "clang/Frontend/FrontendDiagnostic.h"
 #include "clang/Lex/Preprocessor.h"
+#include "llvm/ADT/Hashing.h"
 #include "llvm/Bitcode/BitcodeReader.h"
 #include "llvm/CodeGen/MachineOptimizationRemarkEmitter.h"
 #include "llvm/Demangle/Demangle.h"
@@ -125,6 +126,8 @@
     std::unique_ptr<CodeGenerator> Gen;
 
     SmallVector<LinkModule, 4> LinkModules;
+    std::vector<std::pair<llvm::hash_code, FullSourceLoc>>
+        ManglingFullSourceLocs;
 
     // This is here so that the diagnostic printer knows the module a diagnostic
     // refers to.
@@ -330,6 +333,14 @@
       if (LinkInModules())
         return;
 
+      for (auto &F : getModule()->functions()) {
+        if (const Decl *FD = Gen->GetDeclForMangledName(F.getName())) {
+          auto Loc = FD->getASTContext().getFullLoc(FD->getLocation());
+          auto NameHash = llvm::hash_value(F.getName());
+          ManglingFullSourceLocs.push_back(std::make_pair(NameHash, Loc));
+        }
+      }
+
       EmbedBitcode(getModule(), CodeGenOpts, llvm::MemoryBufferRef());
 
       EmitBackendOutput(Diags, HeaderSearchOpts, CodeGenOpts, TargetOpts,
@@ -376,6 +387,8 @@
                                 bool &BadDebugInfo, StringRef &Filename,
                                 unsigned &Line, unsigned &Column) const;
 
+    Optional<FullSourceLoc> getFunctionSourceLocation(const Function &F) const;
+
     void DiagnosticHandlerImpl(const llvm::DiagnosticInfo &DI);
     /// Specialized handler for InlineAsm diagnostic.
     /// \return True if the diagnostic has been successfully reported, false
@@ -569,17 +582,16 @@
     // We do not know how to format other severities.
     return false;
 
-  if (const Decl *ND = Gen->GetDeclForMangledName(D.getFunction().getName())) {
-    // FIXME: Shouldn't need to truncate to uint32_t
-    Diags.Report(ND->getASTContext().getFullLoc(ND->getLocation()),
-                 diag::warn_fe_frame_larger_than)
-        << static_cast<uint32_t>(D.getStackSize())
-        << static_cast<uint32_t>(D.getStackLimit())
-        << Decl::castToDeclContext(ND);
-    return true;
-  }
+  auto Loc = getFunctionSourceLocation(D.getFunction());
+  if (!Loc)
+    return false;
 
-  return false;
+  // FIXME: Shouldn't need to truncate to uint32_t
+  Diags.Report(*Loc, diag::warn_fe_frame_larger_than)
+      << static_cast<uint32_t>(D.getStackSize())
+      << static_cast<uint32_t>(D.getStackLimit())
+      << llvm::demangle(D.getFunction().getName().str());
+  return true;
 }
 
 const FullSourceLoc BackendConsumer::getBestLocationFromDebugLoc(
@@ -608,9 +620,10 @@
   // function definition. We use the definition's right brace to differentiate
   // from diagnostics that genuinely relate to the function itself.
   FullSourceLoc Loc(DILoc, SourceMgr);
-  if (Loc.isInvalid())
-    if (const Decl *FD = Gen->GetDeclForMangledName(D.getFunction().getName()))
-      Loc = FD->getASTContext().getFullLoc(FD->getLocation());
+  if (Loc.isInvalid()) {
+    if (auto MaybeLoc = getFunctionSourceLocation(D.getFunction()))
+      Loc = *MaybeLoc;
+  }
 
   if (DILoc.isInvalid() && D.isLocationAvailable())
     // If we were not able to translate the file:line:col information
@@ -623,6 +636,16 @@
   return Loc;
 }
 
+Optional<FullSourceLoc>
+BackendConsumer::getFunctionSourceLocation(const Function &F) const {
+  auto Hash = llvm::hash_value(F.getName());
+  for (const auto &Pair : ManglingFullSourceLocs) {
+    if (Pair.first == Hash)
+      return Pair.second;
+  }
+  return Optional<FullSourceLoc>();
+}
+
 void BackendConsumer::UnsupportedDiagHandler(
     const llvm::DiagnosticInfoUnsupported &D) {
   // We only support warnings or errors.
diff --git a/clang/test/Frontend/backend-diagnostic.c b/clang/test/Frontend/backend-diagnostic.c
--- a/clang/test/Frontend/backend-diagnostic.c
+++ b/clang/test/Frontend/backend-diagnostic.c
@@ -15,9 +15,9 @@
 
 extern void doIt(char *);
 
-// REGULAR: warning: stack frame size ([[#]]) exceeds limit ([[#]]) in function 'stackSizeWarning'
-// PROMOTE: error: stack frame size ([[#]]) exceeds limit ([[#]]) in function 'stackSizeWarning'
-// IGNORE-NOT: stack frame size ([[#]]) exceeds limit ([[#]]) in function 'stackSizeWarning'
+// REGULAR: warning: stack frame size ([[#]]) exceeds limit ([[#]]) in 'stackSizeWarning'
+// PROMOTE: error: stack frame size ([[#]]) exceeds limit ([[#]]) in 'stackSizeWarning'
+// IGNORE-NOT: stack frame size ([[#]]) exceeds limit ([[#]]) in 'stackSizeWarning'
 void stackSizeWarning() {
   char buffer[80];
   doIt(buffer);
diff --git a/clang/test/Misc/backend-stack-frame-diagnostics-fallback.cpp b/clang/test/Misc/backend-stack-frame-diagnostics-fallback.cpp
--- a/clang/test/Misc/backend-stack-frame-diagnostics-fallback.cpp
+++ b/clang/test/Misc/backend-stack-frame-diagnostics-fallback.cpp
@@ -12,7 +12,7 @@
     virtual void f();
   };
 
-  // CHECK: warning: stack frame size ([[#]]) exceeds limit ([[#]]) in function 'frameSizeThunkWarning::B::f'
+  // CHECK: warning: stack frame size ([[#]]) exceeds limit ([[#]]) in 'frameSizeThunkWarning::B::f()'
   // CHECK: warning: stack frame size ([[#]]) exceeds limit ([[#]]) in function '_ZTv0_n12_N21frameSizeThunkWarning1B1fEv'
   void B::f() {
     volatile int x = 0; // Ensure there is stack usage.
diff --git a/clang/test/Misc/backend-stack-frame-diagnostics.cpp b/clang/test/Misc/backend-stack-frame-diagnostics.cpp
--- a/clang/test/Misc/backend-stack-frame-diagnostics.cpp
+++ b/clang/test/Misc/backend-stack-frame-diagnostics.cpp
@@ -26,7 +26,7 @@
 
 void frameSizeWarning();
 
-void frameSizeWarning() { // expected-warning-re {{stack frame size ({{[0-9]+}}) exceeds limit ({{[0-9]+}}) in function 'frameSizeWarning'}}
+void frameSizeWarning() { // expected-warning-re {{stack frame size ({{[0-9]+}}) exceeds limit ({{[0-9]+}}) in 'frameSizeWarning()'}}
   char buffer[80];
   doIt(buffer);
 }
@@ -45,7 +45,7 @@
 
 void frameSizeLocalClassWarning() {
   struct S {
-    S() { // expected-warning-re {{stack frame size ({{[0-9]+}}) exceeds limit ({{[0-9]+}}) in function 'frameSizeLocalClassWarning()::S::S'}}
+    S() { // expected-warning-re {{stack frame size ({{[0-9]+}}) exceeds limit ({{[0-9]+}}) in 'frameSizeLocalClassWarning()::S::S()'}}
       char buffer[80];
       doIt(buffer);
     }
@@ -55,7 +55,7 @@
 
 void frameSizeLambdaWarning() {
   auto fn =
-      []() { // expected-warning-re {{stack frame size ({{[0-9]+}}) exceeds limit ({{[0-9]+}}) in lambda expression}}
+      []() { // expected-warning-re {{stack frame size ({{[0-9]+}}) exceeds limit ({{[0-9]+}}) in 'frameSizeLambdaWarning()::$_0::operator()() const'}}
     char buffer[80];
     doIt(buffer);
   };
@@ -64,7 +64,7 @@
 
 void frameSizeBlocksWarning() {
   auto fn =
-      ^() { // expected-warning-re {{stack frame size ({{[0-9]+}}) exceeds limit ({{[0-9]+}}) in block literal}}
+      ^() { // expected-warning-re {{stack frame size ({{[0-9]+}}) exceeds limit ({{[0-9]+}}) in 'invocation function for block in frameSizeBlocksWarning()'}}
     char buffer[80];
     doIt(buffer);
   };