[MS] Mangle a hash of the main file path into anonymous namespaces

[rnk]

Summary

This is needed to avoid conflicts in mangled names for codeview types in
anonymous namespaces. In CodeView, types refer to each other typically
through forward declarations, which contain mangled names. These names
have to be unique, otherwise the debugger will look up the mangled name
and find the wrong definition.

Furthermore, ThinLTO will deduplicate the types, and debug info
verification can fail when the types have the wrong sizes. This is
PR38608.

Fixes PR38609.

[majnemer]

How does MSVC handle this case? What mangled name does it generate?

[zturner]

IIRC it’s ?A0xABCDABCD@ where the hex value is some kind of hash

[inglorion]

clang/lib/AST/MicrosoftMangle.cpp

390

Instead of MD5, can we use xxhash (or whatever the fastest hash algorithm in LLVM is these days)? I don't think we need a particular hash algorithm, so we might as well go with the fastest one we have (as long as it does a good job avoiding collisions, of course).

[rnk]

• Use xxHash64

[rnk]

Exactly, this makes our names match MSVC more closely. Their hash depends on the path to the main source file. It doesn't care if the file is in a header. However, they use the absolute path to the file instead of the (probably relative) path to the file passed by the build system on the command line. I think my approach of using the spelling of the path on the command line will play better with distributed build systems, since you can imagine multiple distributed workers compiling at different absolute paths.

clang/lib/AST/MicrosoftMangle.cpp

390

Sure. It's not visible in the ABI, so we're free to change it at any point later.

[thakis]

Can you explicitly mention that this intentionally doesn't use an absolute path in MicrosoftMangleContextImpl() or similar?

[rnk]

• improve comment

[rnk]

In D50877#1204609, @thakis wrote:

Can you explicitly mention that this intentionally doesn't use an absolute path in MicrosoftMangleContextImpl() or similar?

Sure. I also described the issue with codeview that motivates why we want unique names.

I think I sent this out hastily at the end of the day yesterday, and I didn't write enough comments to answer all of your questions. Hopefully with these changes it makes more sense.

clang/lib/AST/MicrosoftMangle.cpp

 #include "clang/AST/Expr.h"
 #include "clang/AST/ExprCXX.h"
 #include "clang/AST/VTableBuilder.h"
 #include "clang/Basic/ABI.h"
 #include "clang/Basic/DiagnosticOptions.h"
 #include "clang/Basic/TargetInfo.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/Support/JamCRC.h"
+#include "llvm/Support/xxhash.h"
 #include "llvm/Support/MD5.h"
 #include "llvm/Support/MathExtras.h"
 
 using namespace clang;
 
 namespace {
 
 struct msvc_hashing_ostream : public llvm::raw_svector_ostream {

 /// Microsoft Visual C++ ABI.
 class MicrosoftMangleContextImpl : public MicrosoftMangleContext {
   typedef std::pair<const DeclContext *, IdentifierInfo *> DiscriminatorKeyTy;
   llvm::DenseMap<DiscriminatorKeyTy, unsigned> Discriminator;
   llvm::DenseMap<const NamedDecl *, unsigned> Uniquifier;
   llvm::DenseMap<const CXXRecordDecl *, unsigned> LambdaIds;
   llvm::DenseMap<const NamedDecl *, unsigned> SEHFilterIds;
   llvm::DenseMap<const NamedDecl *, unsigned> SEHFinallyIds;
+  SmallString<16> AnonymousNamespaceHash;
 
 public:
-  MicrosoftMangleContextImpl(ASTContext &Context, DiagnosticsEngine &Diags)
-      : MicrosoftMangleContext(Context, Diags) {}
+  MicrosoftMangleContextImpl(ASTContext &Context, DiagnosticsEngine &Diags);
   bool shouldMangleCXXName(const NamedDecl *D) override;
   bool shouldMangleStringLiteral(const StringLiteral *SL) override;
   void mangleCXXName(const NamedDecl *D, raw_ostream &Out) override;
   void mangleVirtualMemPtrThunk(const CXXMethodDecl *MD,
                                 const MethodVFTableLocation &ML,
                                 raw_ostream &Out) override;
   void mangleThunk(const CXXMethodDecl *MD, const ThunkInfo &Thunk,
                    raw_ostream &) override;
unsigned getLambdaId(const CXXRecordDecl *RD) {
     assert(!RD->isExternallyVisible() && "RD must not be visible!");
     assert(RD->getLambdaManglingNumber() == 0 &&
            "RD must not have a mangling number!");
     std::pair<llvm::DenseMap<const CXXRecordDecl *, unsigned>::iterator, bool>
         Result = LambdaIds.insert(std::make_pair(RD, LambdaIds.size()));
     return Result.first->second;
   }
 
+  /// Return a character sequence that is (somewhat) unique to the TU suitable
+  /// for mangling anonymous namespaces.
+  StringRef getAnonymousNamespaceHash() const {
+    return AnonymousNamespaceHash;
+  }
+
 private:
   void mangleInitFiniStub(const VarDecl *D, char CharCode, raw_ostream &Out);
 };
 
 /// MicrosoftCXXNameMangler - Manage the mangling of a single name for the
 /// Microsoft Visual C++ ABI.
 class MicrosoftCXXNameMangler {
   MicrosoftMangleContextImpl &Context;
void mangleTemplateArg(const TemplateDecl *TD, const TemplateArgument &TA,
                          const NamedDecl *Parm);
 
   void mangleObjCProtocol(const ObjCProtocolDecl *PD);
   void mangleObjCLifetime(const QualType T, Qualifiers Quals,
                           SourceRange Range);
 };
 }
 
+MicrosoftMangleContextImpl::MicrosoftMangleContextImpl(ASTContext &Context,
+                                                       DiagnosticsEngine &Diags)
+    : MicrosoftMangleContext(Context, Diags) {
+  // To mangle anonymous namespaces, hash the path to the main source file. The
+  // path should be whatever (probably relative) path was passed on the command
+  // line. The goal is for the compiler to produce the same output regardless of
+  // working directory, so use the uncanonicalized relative path.
+  //
+  // It's important to make the mangled names unique because, when CodeView
+  // debug info is in use, the debugger uses mangled type names to distinguish
+  // between otherwise identically named types in anonymous namespaces.
+  //
+  // These symbols are always internal, so there is no need for the hash to
+  // match what MSVC produces. For the same reason, clang is free to change the
+  // hash at any time without breaking compatibility with old versions of clang.
+  // The generated names are intended to look similar to what MSVC generates,
+  // which are something like "?A0x01234567@".
+  SourceManager &SM = Context.getSourceManager();
+  if (const FileEntry *FE = SM.getFileEntryForID(SM.getMainFileID())) {
+    // Truncate the hash so we get 8 characters of hexadecimal.
+    uint32_t TruncatedHash = uint32_t(xxHash64(FE->getName()));
+    AnonymousNamespaceHash = llvm::utohexstr(TruncatedHash);
+  } else {
+    // If we don't have a path to the main file, we'll just use 0.
+    AnonymousNamespaceHash = "0";
+  }
+}
+
 bool MicrosoftMangleContextImpl::shouldMangleCXXName(const NamedDecl *D) {
   if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
     LanguageLinkage L = FD->getLanguageLinkage();
     // Overloadable functions need mangling.
     if (FD->hasAttr<OverloadableAttr>())
       return true;
 
     // The ABI expects that we would never mangle "typical" user-defined entry
case DeclarationName::Identifier: {
         break;
       }
 
       // Otherwise, an anonymous entity.  We must have a declaration.
       assert(ND && "mangling empty name without declaration");
 
       if (const NamespaceDecl *NS = dyn_cast<NamespaceDecl>(ND)) {
         if (NS->isAnonymousNamespace()) {
-          Out << "?A@";
+          Out << "?A0x" << Context.getAnonymousNamespaceHash() << '@';
           break;
         }
       }
 
       if (const DecompositionDecl *DD = dyn_cast<DecompositionDecl>(ND)) {
         // FIXME: Invented mangling for decomposition declarations:
         //   [X,Y,Z]
         // where X,Y,Z are the names of the bindings.

clang/test/CodeGenCXX/cfi-cross-dso.cpp

 void B::f() {}
 } // namespace
 
 void g() {
   B b;
   b.f();
 }
 
-// MS: @[[B_VTABLE:.*]] = private unnamed_addr constant { [2 x i8*] } {{.*}}@"??_R4B@?A@@6B@"{{.*}}@"?f@B@?A@@UEAAXXZ"
+// MS: @[[B_VTABLE:.*]] = private unnamed_addr constant { [2 x i8*] } {{.*}}@"??_R4B@?A0x{{[^@]*}}@@6B@"{{.*}}@"?f@B@?A0x{{[^@]*}}@@UEAAXXZ"
 
 // CHECK:   %[[VT:.*]] = load void (%struct.A*)**, void (%struct.A*)***
 // CHECK:   %[[VT2:.*]] = bitcast {{.*}}%[[VT]] to i8*, !nosanitize
 // ITANIUM:   %[[TEST:.*]] = call i1 @llvm.type.test(i8* %[[VT2]], metadata !"_ZTS1A"), !nosanitize
 // MS:   %[[TEST:.*]] = call i1 @llvm.type.test(i8* %[[VT2]], metadata !"?AUA@@"), !nosanitize
 // CHECK:   br i1 %[[TEST]], label %[[CONT:.*]], label %[[SLOW:.*]], {{.*}} !nosanitize
 // CHECK: [[SLOW]]
 // ITANIUM:   call void @__cfi_slowpath_diag(i64 7004155349499253778, i8* %[[VT2]], {{.*}}) {{.*}} !nosanitize
 // MS:   call void @__cfi_slowpath_diag(i64 -8005289897957287421, i8* %[[VT2]], {{.*}}) {{.*}} !nosanitize
 // CHECK:   br label %[[CONT]], !nosanitize
 // CHECK: [[CONT]]
 // CHECK:   call void %{{.*}}(%struct.A* %{{.*}})
 
 // No hash-based bit set entry for (anonymous namespace)::B
 // ITANIUM-NOT: !{i64 {{.*}}, [3 x i8*]* @_ZTVN12_GLOBAL__N_11BE,
 // MS-NOT: !{i64 {{.*}}, [2 x i8*]* @[[B_VTABLE]],

clang/test/CodeGenCXX/cfi-icall.cpp

 void g() {
   struct S s;
   void (*fp)(S) = f;
   // CHECK: call i1 @llvm.type.test(i8* {{.*}}, metadata [[VOIDS1:![0-9]+]])
   fp(s);
 }
 
 // ITANIUM: define internal void @_ZN12_GLOBAL__N_11fENS_1SE({{.*}} !type [[TS1:![0-9]+]] !type [[TS2:![0-9]+]]
-// MS: define internal void @"?f@?A@@YAXUS@?A@@@Z"({{.*}} !type [[TS1:![0-9]+]] !type [[TS2:![0-9]+]]
+// MS: define internal void @"?f@?A0x{{[^@]*}}@@YAXUS@?A0x{{[^@]*}}@@@Z"({{.*}} !type [[TS1:![0-9]+]] !type [[TS2:![0-9]+]]
 
 // CHECK: [[VOIDS1]] = distinct !{}
 // CHECK: [[TS1]] = !{i64 0, [[VOIDS1]]}
 // CHECK: [[TS2]] = !{i64 0, [[VOIDS2:![0-9]+]]}
 // CHECK: [[VOIDS2]] = distinct !{}

clang/test/CodeGenCXX/debug-info-thunk.cpp

namespace Test4 {
 
   namespace {
     struct C : A, B {
       virtual void c();
       virtual void f();
     };
   }
   void C::c() {}
-// CHECK-DAG: DISubprogram{{.*}}linkageName: "?f@C@?A@Test4@@W7EAAXXZ"{{.*}} flags: {{.*}}DIFlagThunk
+// CHECK-DAG: DISubprogram{{.*}}linkageName: "?f@C@?A0x{{[^@]*}}@Test4@@W7EAAXXZ"{{.*}} flags: {{.*}}DIFlagThunk
   void C::f() {}
 
   // Force C::f to be used.
   void f() { 
     C c; 
     c.f();
   }
 }

clang/test/CodeGenCXX/dllexport.cpp

 // G32-DAG: define weak_odr dso_local x86_thiscallcc void @_ZN69ImplicitInstantiationExportedExplicitInstantiationDefExportedTemplateIiE1fEv
 
 namespace { struct InternalLinkageType {}; }
 struct __declspec(dllexport) PR23308 {
   void f(InternalLinkageType*);
 };
 void PR23308::f(InternalLinkageType*) {}
 long use(PR23308* p) { p->f(nullptr); }
-// M32-DAG: define internal x86_thiscallcc void @"?f@PR23308@@QAEXPAUInternalLinkageType@?A@@@Z"
+// M32-DAG: define internal x86_thiscallcc void @"?f@PR23308@@QAEXPAUInternalLinkageType@?A0x{{[^@]*}}@@@Z"
 
 template <typename T> struct PR23770BaseTemplate { void f() {} };
 template <typename T> struct PR23770DerivedTemplate : PR23770BaseTemplate<int> {};
 extern template struct PR23770DerivedTemplate<int>;
 template struct __declspec(dllexport) PR23770DerivedTemplate<int>;
 // M32-DAG: define weak_odr dso_local dllexport x86_thiscallcc void @"?f@?$PR23770BaseTemplate@H@@QAEXXZ"
 
 namespace InClassInits {

clang/test/CodeGenCXX/mangle-ms.cpp

 }
 
 namespace N {
   int b;
 // CHECK-DAG: @"?b@N@@3HA"
 
   namespace {
     int anonymous;
-// CHECK-DAG: @"?anonymous@?A@N@@3HA"
+// CHECK-DAG: @"?anonymous@?A0x{{[^@]*}}@N@@3HA"
   }
 }
 
 static int c;
 // CHECK-DAG: @c
 
 int _c(void) {return N::anonymous + c;}
 // CHECK-DAG: @"?_c@@YAHXZ"

clang/test/CodeGenCXX/microsoft-abi-structors.cpp

 namespace {
 struct A {
   virtual ~A() { }
 };
 }
 void *getA() {
   return (void*)new A();
 }
-// CHECK: define internal x86_thiscallcc i8* @"??_GA@?A@@UAEPAXI@Z"
+// CHECK: define internal x86_thiscallcc i8* @"??_GA@?A0x{{[^@]*}}@@UAEPAXI@Z"
 // CHECK:               (%"struct.(anonymous namespace)::A"* %this, i32 %should_call_delete)
-// CHECK: define internal x86_thiscallcc void @"??1A@?A@@UAE@XZ"
+// CHECK: define internal x86_thiscallcc void @"??1A@?A0x{{[^@]*}}@@UAE@XZ"
 // CHECK:               (%"struct.(anonymous namespace)::A"* %this)
 
 // Check that we correctly transform __stdcall to __thiscall for ctors and
 // dtors.
 class G {
  public:
   __stdcall G() {};
 // DTORS4: define linkonce_odr dso_local x86_thiscallcc %class.G* @"??0G@@QAE@XZ"
   __stdcall ~G() {};
 // DTORS4: define linkonce_odr dso_local x86_thiscallcc void @"??1G@@QAE@XZ"
 };
 
 extern void testG() {
   G g;
 }

clang/test/CodeGenCXX/microsoft-abi-throw.cpp

 // CHECK-DAG: @"_CT??_R0?AUVariadic@@@8??_OVariadic@@QAEXAAU0@@Z1" = linkonce_odr unnamed_addr constant %eh.CatchableType { i32 0, i8* bitcast (%rtti.TypeDescriptor14* @"??_R0?AUVariadic@@@8" to i8*), i32 0, i32 -1, i32 0, i32 1, i8* bitcast (void (%struct.Variadic*, %struct.Variadic*)* @"??_OVariadic@@QAEXAAU0@@Z" to i8*) }, section ".xdata", comdat
 // CHECK-DAG: @"_CT??_R0?AUTemplateWithDefault@@@8??$?_OH@TemplateWithDefault@@QAEXAAU0@@Z1" = linkonce_odr unnamed_addr constant %eh.CatchableType { i32 0, i8* bitcast (%rtti.TypeDescriptor25* @"??_R0?AUTemplateWithDefault@@@8" to i8*), i32 0, i32 -1, i32 0, i32 1, i8* bitcast (void (%struct.TemplateWithDefault*, %struct.TemplateWithDefault*)* @"??$?_OH@TemplateWithDefault@@QAEXAAU0@@Z" to i8*) }, section ".xdata", comdat
 // CHECK-DAG: @"_CTA2$$T" = linkonce_odr unnamed_addr constant %eh.CatchableTypeArray.2 { i32 2, [2 x %eh.CatchableType*] [%eh.CatchableType* @"_CT??_R0$$T@84", %eh.CatchableType* @"_CT??_R0PAX@84"] }, section ".xdata", comdat
 // CHECK-DAG: @"_CT??_R0P6AXXZ@84" = linkonce_odr unnamed_addr constant %eh.CatchableType { i32 1, i8* bitcast (%rtti.TypeDescriptor7* @"??_R0P6AXXZ@8" to i8*), i32 0, i32 -1, i32 0, i32 4, i8* null }, section ".xdata", comdat
 // CHECK-DAG: @_CTA1P6AXXZ = linkonce_odr unnamed_addr constant %eh.CatchableTypeArray.1 { i32 1, [1 x %eh.CatchableType*] [%eh.CatchableType* @"_CT??_R0P6AXXZ@84"] }, section ".xdata", comdat
 // CHECK-DAG: @_TI1P6AXXZ = linkonce_odr unnamed_addr constant %eh.ThrowInfo { i32 0, i8* null, i8* null, i8* bitcast (%eh.CatchableTypeArray.1* @_CTA1P6AXXZ to i8*) }, section ".xdata", comdat
 // CHECK-DAG: @_TIU2PAPFAH = linkonce_odr unnamed_addr constant %eh.ThrowInfo { i32 4, i8* null, i8* null, i8* bitcast (%eh.CatchableTypeArray.2* @_CTA2PAPFAH to i8*) }, section ".xdata", comdat
 // CHECK-DAG: @_CTA2PAPFAH = linkonce_odr unnamed_addr constant %eh.CatchableTypeArray.2 { i32 2, [2 x %eh.CatchableType*] [%eh.CatchableType* @"_CT??_R0PAPFAH@84", %eh.CatchableType* @"_CT??_R0PAX@84"] }, section ".xdata", comdat
-// CHECK-DAG: @"_TI1?AUFoo@?A@@" = internal unnamed_addr constant %eh.ThrowInfo { i32 0, i8* null, i8* null, i8* bitcast (%eh.CatchableTypeArray.1* @"_CTA1?AUFoo@?A@@" to i8*) }, section ".xdata"
+// CHECK-DAG: @"_TI1?AUFoo@?A0x{{[^@]*}}@@" = internal unnamed_addr constant %eh.ThrowInfo { i32 0, i8* null, i8* null, i8* bitcast (%eh.CatchableTypeArray.1* @"_CTA1?AUFoo@?A0x{{[^@]*}}@@" to i8*) }, section ".xdata"
 
 
 struct N { ~N(); };
 struct M : private N {};
 struct X {};
 struct Z {};
 struct V : private X {};
 struct W : M, virtual V {};
// CHECK:  ret i8* bitcast (%eh.ThrowInfo* @_TI1P6AXXZ to i8*)
   return __GetExceptionInfo<void (*)()>(&h);
 }
 
 // PR36327: Try an exception type with no linkage.
 namespace { struct Foo { } foo_exc; }
 
 void *GetExceptionInfo_test2() {
 // CHECK-LABEL: @"?GetExceptionInfo_test2@@YAPAXXZ"
-// CHECK:  ret i8* bitcast (%eh.ThrowInfo* @"_TI1?AUFoo@?A@@" to i8*)
+// CHECK:  ret i8* bitcast (%eh.ThrowInfo* @"_TI1?AUFoo@?A0x{{[^@]*}}@@" to i8*)
   return __GetExceptionInfo(foo_exc);
 }

clang/test/CodeGenCXX/microsoft-abi-thunks.cpp

 namespace {
 struct E : D {
   E();
   virtual C* goo();
 };
 E::E() {}
 E e;
 // Class with internal linkage has internal linkage thunks.
-// CODEGEN: define internal x86_thiscallcc %struct.C* @"?goo@E@?A@@QAEPAUB@@XZ"
+// CODEGEN: define internal x86_thiscallcc %struct.C* @"?goo@E@?A0x{{[^@]*}}@@QAEPAUB@@XZ"
 }

clang/test/CodeGenCXX/microsoft-abi-vftables.cpp

 
 // NO-RTTI-DAG: @"??_7V@@6B@" = weak_odr dllexport unnamed_addr constant { [1 x i8*] } { [1 x i8*] [i8* bitcast ({{.*}} @"??_GV@@UAEPAXI@Z" to i8*)] }
 
 namespace {
 struct W {
   virtual ~W() {}
 } w;
 }
-// RTTI-DAG: [[VTABLE_W:@.*]] = private unnamed_addr constant { [2 x i8*] } { [2 x i8*] [i8* bitcast ({{.*}} @"??_R4W@?A@@6B@" to i8*), i8* bitcast ({{.*}} @"??_GW@?A@@UAEPAXI@Z" to i8*)] }
-// RTTI-DAG: @"??_7W@?A@@6B@" = internal unnamed_addr alias i8*, getelementptr inbounds ({ [2 x i8*] }, { [2 x i8*] }* [[VTABLE_W]], i32 0, i32 0, i32 1)
+// RTTI-DAG: [[VTABLE_W:@.*]] = private unnamed_addr constant { [2 x i8*] } { [2 x i8*] [i8* bitcast ({{.*}} @"??_R4W@?A0x{{[^@]*}}@@6B@" to i8*), i8* bitcast ({{.*}} @"??_GW@?A0x{{[^@]*}}@@UAEPAXI@Z" to i8*)] }
+// RTTI-DAG: @"??_7W@?A0x{{[^@]*}}@@6B@" = internal unnamed_addr alias i8*, getelementptr inbounds ({ [2 x i8*] }, { [2 x i8*] }* [[VTABLE_W]], i32 0, i32 0, i32 1)
 
-// NO-RTTI-DAG: @"??_7W@?A@@6B@" = internal unnamed_addr constant { [1 x i8*] } { [1 x i8*] [i8* bitcast ({{.*}} @"??_GW@?A@@UAEPAXI@Z" to i8*)] }
+// NO-RTTI-DAG: @"??_7W@?A0x{{[^@]*}}@@6B@" = internal unnamed_addr constant { [1 x i8*] } { [1 x i8*] [i8* bitcast ({{.*}} @"??_GW@?A0x{{[^@]*}}@@UAEPAXI@Z" to i8*)] }
 
 struct X {};
 template <class> struct Y : virtual X {
   Y() {}
   virtual ~Y();
 };
 
 extern template class Y<int>;
 template Y<int>::Y();
 // RTTI-DAG: [[VTABLE_Y:@.*]] = private unnamed_addr constant { [2 x i8*] } { [2 x i8*] [i8* bitcast (%rtti.CompleteObjectLocator* @"??_R4?$Y@H@@6B@" to i8*), i8* bitcast (i8* (%struct.Y*, i32)* @"??_G?$Y@H@@UAEPAXI@Z" to i8*)] }, comdat($"??_7?$Y@H@@6B@")
 // RTTI-DAG: @"??_7?$Y@H@@6B@" = unnamed_addr alias i8*, getelementptr inbounds ({ [2 x i8*] }, { [2 x i8*] }* [[VTABLE_Y]], i32 0, i32 0, i32 1)
 
 // NO-RTTI-DAG: @"??_7?$Y@H@@6B@" = linkonce_odr unnamed_addr constant { [1 x i8*] } { [1 x i8*] [i8* bitcast (i8* (%struct.Y*, i32)* @"??_G?$Y@H@@UAEPAXI@Z" to i8*)] }, comdat

clang/test/CodeGenCXX/microsoft-abi-virtual-member-pointers.cpp

void f() {
 
   auto ptr7 = &C::plugh;
 
 
 // CHECK32-LABEL: define dso_local void @"?f@@YAXXZ"()
 // CHECK32: store i8* bitcast (void (%struct.C*, ...)* @"??_9C@@$BA@AE" to i8*), i8** %ptr
 // CHECK32: store i8* bitcast (void (%struct.C*, ...)* @"??_9C@@$B3AE" to i8*), i8** %ptr2
 // CHECK32: store i8* bitcast (void (%struct.C*, ...)* @"??_9C@@$B7AE" to i8*), i8** %ptr3
-// CHECK32: store i8* bitcast (void (%"struct.(anonymous namespace)::D"*, ...)* @"??_9D@?A@@$BA@AE" to i8*), i8** %ptr4
+// CHECK32: store i8* bitcast (void (%"struct.(anonymous namespace)::D"*, ...)* @"??_9D@?A0x{{[^@]*}}@@$BA@AE" to i8*), i8** %ptr4
 // CHECK32: }
 //
 // CHECK64-LABEL: define dso_local void @"?f@@YAXXZ"()
 // CHECK64: store i8* bitcast (void (%struct.C*, ...)* @"??_9C@@$BA@AA" to i8*), i8** %ptr
 // CHECK64: store i8* bitcast (void (%struct.C*, ...)* @"??_9C@@$B7AA" to i8*), i8** %ptr2
 // CHECK64: store i8* bitcast (void (%struct.C*, ...)* @"??_9C@@$BBA@AA" to i8*), i8** %ptr3
-// CHECK64: store i8* bitcast (void (%"struct.(anonymous namespace)::D"*, ...)* @"??_9D@?A@@$BA@AA" to i8*), i8** %ptr
+// CHECK64: store i8* bitcast (void (%"struct.(anonymous namespace)::D"*, ...)* @"??_9D@?A0x{{[^@]*}}@@$BA@AA" to i8*), i8** %ptr
 // CHECK64: }
 }
 
 
 // Thunk for calling the 1st virtual function in C with no parameters.
 // CHECK32-LABEL: define linkonce_odr x86_thiscallcc void @"??_9C@@$BA@AE"(%struct.C* %this, ...)
 // CHECK32: #[[ATTR:[0-9]+]]
 // CHECK32-NOT:             unnamed_addr

 // CHECK64: #[[ATTR]] comdat
 // CHECK64: [[VPTR:%.*]] = getelementptr inbounds void (%struct.C*, ...)*, void (%struct.C*, ...)** %{{.*}}, i64 2
 // CHECK64: [[CALLEE:%.*]] = load void (%struct.C*, ...)*, void (%struct.C*, ...)** [[VPTR]]
 // CHECK64: musttail call void (%struct.C*, ...) [[CALLEE]](%struct.C* %{{.*}}, ...)
 // CHECK64-NEXT: ret void
 // CHECK64: }
 
 // Thunk for calling the virtual function in internal class D.
-// CHECK32-LABEL: define internal x86_thiscallcc void @"??_9D@?A@@$BA@AE"(%"struct.(anonymous namespace)::D"* %this, ...)
+// CHECK32-LABEL: define internal x86_thiscallcc void @"??_9D@?A0x{{[^@]*}}@@$BA@AE"(%"struct.(anonymous namespace)::D"* %this, ...)
 // CHECK32: #[[ATTR]]
 // CHECK32: [[VPTR:%.*]] = getelementptr inbounds void (%"struct.(anonymous namespace)::D"*, ...)*, void (%"struct.(anonymous namespace)::D"*, ...)** %{{.*}}, i64 0
 // CHECK32: [[CALLEE:%.*]] = load void (%"struct.(anonymous namespace)::D"*, ...)*, void (%"struct.(anonymous namespace)::D"*, ...)** [[VPTR]]
 // CHECK32: musttail call x86_thiscallcc void (%"struct.(anonymous namespace)::D"*, ...) [[CALLEE]](%"struct.(anonymous namespace)::D"* %{{.*}}, ...)
 // CHECK32-NEXT: ret void
 // CHECK32: }
 //
-// CHECK64-LABEL: define internal void @"??_9D@?A@@$BA@AA"(%"struct.(anonymous namespace)::D"* %this, ...)
+// CHECK64-LABEL: define internal void @"??_9D@?A0x{{[^@]*}}@@$BA@AA"(%"struct.(anonymous namespace)::D"* %this, ...)
 // CHECK64: #[[ATTR]]
 // CHECK64: [[VPTR:%.*]] = getelementptr inbounds void (%"struct.(anonymous namespace)::D"*, ...)*, void (%"struct.(anonymous namespace)::D"*, ...)** %{{.*}}, i64 0
 // CHECK64: [[CALLEE:%.*]] = load void (%"struct.(anonymous namespace)::D"*, ...)*, void (%"struct.(anonymous namespace)::D"*, ...)** [[VPTR]]
 // CHECK64: musttail call void (%"struct.(anonymous namespace)::D"*, ...) [[CALLEE]](%"struct.(anonymous namespace)::D"* %{{.*}}, ...)
 // CHECK64-NEXT: ret void
 // CHECK64: }
 
 // Thunk for calling the fourth virtual function in C, taking a struct parameter

clang/test/CodeGenCXX/msabi-swiftcall-cc.cpp

 // RUN: %clang_cc1 -triple i686-unknown-windows-msvc -fdeclspec -emit-llvm %s -o - | FileCheck %s
 // RUN: %clang_cc1 -triple x86_64-unknown-windows-msvc -fdeclspec -emit-llvm %s -o - | FileCheck %s -check-prefix CHECK-64
 
 void __attribute__((__swiftcall__)) f() {}
 // CHECK-DAG: @"?f@@YSXXZ"
 // CHECK-64-DAG: @"?f@@YSXXZ"
 
 void (__attribute__((__swiftcall__)) *p)();
 // CHECK-DAG: @"?p@@3P6SXXZA"
 // CHECK-64-DAG: @"?p@@3P6SXXZEA
 
 namespace {
 void __attribute__((__swiftcall__)) __attribute__((__used__)) f() { }
 }
-// CHECK-DAG: @"?f@?A@@YSXXZ"
-// CHECK-64-DAG: @"?f@?A@@YSXXZ"
+// CHECK-DAG: @"?f@?A0x{{[^@]*}}@@YSXXZ"
+// CHECK-64-DAG: @"?f@?A0x{{[^@]*}}@@YSXXZ"
 
 namespace n {
 void __attribute__((__swiftcall__)) f() {}
 }
 // CHECK-DAG: @"?f@n@@YSXXZ"
 // CHECK-64-DAG: @"?f@n@@YSXXZ"
 
 struct __declspec(dllexport) S {

 
 void (__attribute__((__preserve_most__)) *q)();
 // CHECK-DAG: @"?q@@3P6UXXZA"
 // CHECK-64-DAG: @"?q@@3P6UXXZEA"
 
 namespace {
 void __attribute__((__preserve_most__)) __attribute__((__used__)) g() {}
 }
-// CHECK-DAG: @"?g@?A@@YUXXZ"
-// CHECK-64-DAG: @"?g@?A@@YUXXZ"
+// CHECK-DAG: @"?g@?A0x{{[^@]*}}@@YUXXZ"
+// CHECK-64-DAG: @"?g@?A0x{{[^@]*}}@@YUXXZ"
 
 namespace n {
 void __attribute__((__preserve_most__)) g() {}
 }
 // CHECK-DAG: @"?g@n@@YUXXZ"
 // CHECK-64-DAG: @"?g@n@@YUXXZ"
 
 struct __declspec(dllexport) T {

clang/test/CodeGenCXX/pragma-init_seg.cpp

 // No function pointer!  This one goes on @llvm.global_ctors.
 }
 
 #pragma init_seg(".asdf")
 
 namespace internal_init {
 namespace {
 int x = f();
-// CHECK: @"?x@?A@internal_init@@3HA" = internal global i32 0, align 4
-// CHECK: @__cxx_init_fn_ptr.2 = private constant void ()* @"??__Ex@?A@internal_init@@YAXXZ", section ".asdf"
+// CHECK: @"?x@?A0x{{[^@]*}}@internal_init@@3HA" = internal global i32 0, align 4
+// CHECK: @__cxx_init_fn_ptr.2 = private constant void ()* @"??__Ex@?A0x{{[^@]*}}@internal_init@@YAXXZ", section ".asdf"
 }
 }
 
 namespace selectany_init {
 int __declspec(selectany) x = f();
 // CHECK: @"?x@selectany_init@@3HA" = weak_odr dso_local global i32 0, comdat, align 4
 // CHECK: @__cxx_init_fn_ptr.3 = private constant void ()* @"??__Ex@selectany_init@@YAXXZ", section ".asdf", comdat($"?x@selectany_init@@3HA")
 }

clang/test/CodeGenCXX/type-metadata.cpp

 // ITANIUM-SAME: !type [[FA16:![0-9]+]]
 // ITANIUM-DIAG-SAME: !type [[ALL16]]
 // ITANIUM-SAME: !type [[FAF16:![0-9]+]]
 
 // MS: comdat($"??_7A@@6B@"), !type [[A8:![0-9]+]]
 // MS: comdat($"??_7B@@6B0@@"), !type [[B8:![0-9]+]]
 // MS: comdat($"??_7B@@6BA@@@"), !type [[A8]]
 // MS: comdat($"??_7C@@6B@"), !type [[A8]]
-// MS: comdat($"??_7D@?A@@6BB@@@"), !type [[B8]], !type [[D8:![0-9]+]]
-// MS: comdat($"??_7D@?A@@6BA@@@"), !type [[A8]]
+// MS: comdat($"??_7D@?A0x{{[^@]*}}@@6BB@@@"), !type [[B8]], !type [[D8:![0-9]+]]
+// MS: comdat($"??_7D@?A0x{{[^@]*}}@@6BA@@@"), !type [[A8]]
 // MS: comdat($"??_7FA@?1??foo@@YAXXZ@6B@"), !type [[A8]], !type [[FA8:![0-9]+]]
 
 struct A {
   A();
   virtual void f();
 };
 
 struct B : virtual A {
void af(A *a) {
   // CFI-VT: [[PTRI8:%[^ ]*]] = extractvalue { i8*, i1 } [[PAIR]], 0
   // CFI-VT: [[PTR:%[^ ]*]] = bitcast i8* [[PTRI8]] to
   // CFI: call void [[PTR]]
 #line 123
   a->f();
 }
 
 // ITANIUM: define internal void @_Z3df1PN12_GLOBAL__N_11DE
-// MS: define internal void @"?df1@@YAXPEAUD@?A@@@Z"
+// MS: define internal void @"?df1@@YAXPEAUD@?A0x{{[^@]*}}@@@Z"
 void df1(D *d) {
   // TT-ITANIUM: {{%[^ ]*}} = call i1 @llvm.type.test(i8* {{%[^ ]*}}, metadata ![[DTYPE:[0-9]+]])
   // TT-MS: {{%[^ ]*}} = call i1 @llvm.type.test(i8* {{%[^ ]*}}, metadata !"?AUA@@")
   // TC-ITANIUM: {{%[^ ]*}} = call { i8*, i1 } @llvm.type.checked.load(i8* {{%[^ ]*}}, i32 0, metadata ![[DTYPE:[0-9]+]])
   // TC-MS: {{%[^ ]*}} = call { i8*, i1 } @llvm.type.checked.load(i8* {{%[^ ]*}}, i32 0, metadata !"?AUA@@")
   d->f();
 }
 
 // ITANIUM: define internal void @_Z3dg1PN12_GLOBAL__N_11DE
-// MS: define internal void @"?dg1@@YAXPEAUD@?A@@@Z"
+// MS: define internal void @"?dg1@@YAXPEAUD@?A0x{{[^@]*}}@@@Z"
 void dg1(D *d) {
   // TT-ITANIUM: {{%[^ ]*}} = call i1 @llvm.type.test(i8* {{%[^ ]*}}, metadata !"_ZTS1B")
   // TT-MS: {{%[^ ]*}} = call i1 @llvm.type.test(i8* {{%[^ ]*}}, metadata !"?AUB@@")
   // TC-ITANIUM: {{%[^ ]*}} = call { i8*, i1 } @llvm.type.checked.load(i8* {{%[^ ]*}}, i32 8, metadata !"_ZTS1B")
   // TC-MS: {{%[^ ]*}} = call { i8*, i1 } @llvm.type.checked.load(i8* {{%[^ ]*}}, i32 0, metadata !"?AUB@@")
   d->g();
 }
 
 // ITANIUM: define internal void @_Z3dh1PN12_GLOBAL__N_11DE
-// MS: define internal void @"?dh1@@YAXPEAUD@?A@@@Z"
+// MS: define internal void @"?dh1@@YAXPEAUD@?A0x{{[^@]*}}@@@Z"
 void dh1(D *d) {
   // TT-ITANIUM: {{%[^ ]*}} = call i1 @llvm.type.test(i8* {{%[^ ]*}}, metadata ![[DTYPE]])
   // TT-MS: {{%[^ ]*}} = call i1 @llvm.type.test(i8* {{%[^ ]*}}, metadata ![[DTYPE:[0-9]+]])
   // TC-ITANIUM: {{%[^ ]*}} = call { i8*, i1 } @llvm.type.checked.load(i8* {{%[^ ]*}}, i32 16, metadata ![[DTYPE]])
   // TC-MS: {{%[^ ]*}} = call { i8*, i1 } @llvm.type.checked.load(i8* {{%[^ ]*}}, i32 8, metadata ![[DTYPE:[0-9]+]])
   d->h();
 }
 
 // ITANIUM: define internal void @_Z3df2PN12_GLOBAL__N_11DE
-// MS: define internal void @"?df2@@YAXPEAUD@?A@@@Z"
+// MS: define internal void @"?df2@@YAXPEAUD@?A0x{{[^@]*}}@@@Z"
 __attribute__((no_sanitize("cfi")))
 void df2(D *d) {
   // CFI-NVT-NOT: call i1 @llvm.type.test
   // CFI-VT: [[P:%[^ ]*]] = call i1 @llvm.type.test
   // CFI-VT: call void @llvm.assume(i1 [[P]])
   d->f();
 }
 
 // ITANIUM: define internal void @_Z3df3PN12_GLOBAL__N_11DE
-// MS: define internal void @"?df3@@YAXPEAUD@?A@@@Z"
+// MS: define internal void @"?df3@@YAXPEAUD@?A0x{{[^@]*}}@@@Z"
 __attribute__((no_sanitize("address"))) __attribute__((no_sanitize("cfi-vcall")))
 void df3(D *d) {
   // CFI-NVT-NOT: call i1 @llvm.type.test
   // CFI-VT: [[P:%[^ ]*]] = call i1 @llvm.type.test
   // CFI-VT: call void @llvm.assume(i1 [[P]])
   d->f();
 }