Merging r259874:

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r259874 | compnerd | 2016-02-04 20:12:40 -0800 (Thu, 04 Feb 2016) | 8 lines

CodeGen: correct Windows ARM C++ assertion

Because the Decl is explicitly passed as nullptr further up the call chain, it
is possible to invoke isa on a nullptr, which will assert.  Guard against the
nullptr.

Take the opportunity to reuse the helper method rather than re-implementing this
logic.
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git-svn-id: https://llvm.org/svn/llvm-project/cfe/branches/release_38@261158 91177308-0d34-0410-b5e6-96231b3b80d8

Author: zmodem

lib/CodeGen/TargetInfo.cpp

@@ -4868,9 +4868,6 @@ class ARMTargetCodeGenInfo : public TargetCodeGenInfo {
 };
 
 class WindowsARMTargetCodeGenInfo : public ARMTargetCodeGenInfo {
-  void addStackProbeSizeTargetAttribute(const Decl *D, llvm::GlobalValue *GV,
-                                        CodeGen::CodeGenModule &CGM) const;
-
 public:
   WindowsARMTargetCodeGenInfo(CodeGenTypes &CGT, ARMABIInfo::ABIKind K)
       : ARMTargetCodeGenInfo(CGT, K) {}
@@ -4879,18 +4876,6 @@ class WindowsARMTargetCodeGenInfo : public ARMTargetCodeGenInfo {
                            CodeGen::CodeGenModule &CGM) const override;
 };
 
-void WindowsARMTargetCodeGenInfo::addStackProbeSizeTargetAttribute(
-    const Decl *D, llvm::GlobalValue *GV, CodeGen::CodeGenModule &CGM) const {
-  if (!isa<FunctionDecl>(D))
-    return;
-  if (CGM.getCodeGenOpts().StackProbeSize == 4096)
-    return;
-
-  llvm::Function *F = cast<llvm::Function>(GV);
-  F->addFnAttr("stack-probe-size",
-               llvm::utostr(CGM.getCodeGenOpts().StackProbeSize));
-}
-
 void WindowsARMTargetCodeGenInfo::setTargetAttributes(
     const Decl *D, llvm::GlobalValue *GV, CodeGen::CodeGenModule &CGM) const {
   ARMTargetCodeGenInfo::setTargetAttributes(D, GV, CGM);

test/CodeGenCXX/windows-on-arm-stack-probe-size.cpp

@@ -0,0 +1,13 @@
+// RUN: %clang_cc1 -triple thumbv7--windows-msvc -S -emit-llvm -o - -x c++ %s | FileCheck %s
+// RUN: %clang_cc1 -triple thumbv7--windows-itanium -fno-use-cxa-atexit -S -emit-llvm -o - -x c++ %s | FileCheck %s
+
+class C {
+public:
+  ~C();
+};
+
+static C sc;
+void f(const C &ci) { sc = ci; }
+
+// CHECK: atexit
+