IR: Give function GlobalValue::getRealLinkageName() a less misleading…

… name: dropLLVMManglingEscape().

This function gives the wrong answer on some non-ELF platforms in some
cases. The function that does the right thing lives in Mangler.h. To try to
discourage people from using this function, give it a different name.

Differential Revision: https://reviews.llvm.org/D33162

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@303134 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/IR/GlobalValue.h

@@ -441,10 +441,14 @@ class GlobalValue : public Constant {
   void copyAttributesFrom(const GlobalValue *Src);
 
 public:
-  /// If special LLVM prefix that is used to inform the asm printer to not emit
-  /// usual symbol prefix before the symbol name is used then return linkage
-  /// name after skipping this special LLVM prefix.
-  static StringRef getRealLinkageName(StringRef Name) {
+  /// If the given string begins with the GlobalValue name mangling escape
+  /// character '\1', drop it.
+  ///
+  /// This function applies a specific mangling that is used in PGO profiles,
+  /// among other things. If you're trying to get a symbol name for an
+  /// arbitrary GlobalValue, this is not the function you're looking for; see
+  /// Mangler.h.
+  static StringRef dropLLVMManglingEscape(StringRef Name) {
     if (!Name.empty() && Name[0] == '\1')
       return Name.substr(1);
     return Name;

lib/Analysis/OptimizationDiagnosticInfo.cpp

@@ -101,7 +101,7 @@ void MappingTraits<DiagnosticInfoOptimizationBase *>::mapping(
   // These are read-only for now.
   DiagnosticLocation DL = OptDiag->getLocation();
   StringRef FN =
-      GlobalValue::getRealLinkageName(OptDiag->getFunction().getName());
+      GlobalValue::dropLLVMManglingEscape(OptDiag->getFunction().getName());
 
   StringRef PassName(OptDiag->PassName);
   io.mapRequired("Pass", PassName);

lib/Analysis/TargetLibraryInfo.cpp

@@ -540,7 +540,7 @@ static StringRef sanitizeFunctionName(StringRef funcName) {
 
   // Check for \01 prefix that is used to mangle __asm declarations and
   // strip it if present.
-  return GlobalValue::getRealLinkageName(funcName);
+  return GlobalValue::dropLLVMManglingEscape(funcName);
 }
 
 bool TargetLibraryInfoImpl::getLibFunc(StringRef funcName,

lib/CodeGen/AsmPrinter/CodeViewDebug.cpp

@@ -767,7 +767,7 @@ void CodeViewDebug::emitDebugInfoForFunction(const Function *GV,
 
   // If our DISubprogram name is empty, use the mangled name.
   if (FuncName.empty())
-    FuncName = GlobalValue::getRealLinkageName(GV->getName());
+    FuncName = GlobalValue::dropLLVMManglingEscape(GV->getName());
 
   // Emit a symbol subsection, required by VS2012+ to find function boundaries.
   OS.AddComment("Symbol subsection for " + Twine(FuncName));
@@ -2202,7 +2202,7 @@ void CodeViewDebug::emitDebugInfoForGlobals() {
         if (GV->hasComdat()) {
           MCSymbol *GVSym = Asm->getSymbol(GV);
           OS.AddComment("Symbol subsection for " +
-                        Twine(GlobalValue::getRealLinkageName(GV->getName())));
+                        Twine(GlobalValue::dropLLVMManglingEscape(GV->getName())));
           switchToDebugSectionForSymbol(GVSym);
           EndLabel = beginCVSubsection(ModuleDebugFragmentKind::Symbols);
           // FIXME: emitDebugInfoForGlobal() doesn't handle DIExpressions.

lib/CodeGen/AsmPrinter/DwarfUnit.cpp

@@ -647,7 +647,7 @@ void DwarfUnit::addLinkageName(DIE &Die, StringRef LinkageName) {
     addString(Die,
               DD->getDwarfVersion() >= 4 ? dwarf::DW_AT_linkage_name
                                          : dwarf::DW_AT_MIPS_linkage_name,
-              GlobalValue::getRealLinkageName(LinkageName));
+              GlobalValue::dropLLVMManglingEscape(LinkageName));
 }
 
 void DwarfUnit::addTemplateParams(DIE &Buffer, DINodeArray TParams) {

lib/CodeGen/AsmPrinter/WinException.cpp

@@ -101,7 +101,7 @@ void WinException::beginFunction(const MachineFunction *MF) {
       // functions may still refer to it.
       const WinEHFuncInfo &FuncInfo = *MF->getWinEHFuncInfo();
       StringRef FLinkageName =
-          GlobalValue::getRealLinkageName(MF->getFunction()->getName());
+          GlobalValue::dropLLVMManglingEscape(MF->getFunction()->getName());
       emitEHRegistrationOffsetLabel(FuncInfo, FLinkageName);
     }
     shouldEmitLSDA = hasEHFunclets;
@@ -174,7 +174,7 @@ static MCSymbol *getMCSymbolForMBB(AsmPrinter *Asm,
   // their funclet entry block's number.
   const MachineFunction *MF = MBB->getParent();
   const Function *F = MF->getFunction();
-  StringRef FuncLinkageName = GlobalValue::getRealLinkageName(F->getName());
+  StringRef FuncLinkageName = GlobalValue::dropLLVMManglingEscape(F->getName());
   MCContext &Ctx = MF->getContext();
   StringRef HandlerPrefix = MBB->isCleanupFuncletEntry() ? "dtor" : "catch";
   return Ctx.getOrCreateSymbol("?" + HandlerPrefix + "$" +
@@ -252,7 +252,7 @@ void WinException::endFunclet() {
         !CurrentFuncletEntry->isCleanupFuncletEntry()) {
       // If this is a C++ catch funclet (or the parent function),
       // emit a reference to the LSDA for the parent function.
-      StringRef FuncLinkageName = GlobalValue::getRealLinkageName(F->getName());
+      StringRef FuncLinkageName = GlobalValue::dropLLVMManglingEscape(F->getName());
       MCSymbol *FuncInfoXData = Asm->OutContext.getOrCreateSymbol(
           Twine("$cppxdata$", FuncLinkageName));
       Asm->OutStreamer->EmitValue(create32bitRef(FuncInfoXData), 4);
@@ -536,7 +536,7 @@ void WinException::emitCSpecificHandlerTable(const MachineFunction *MF) {
   // Emit a label assignment with the SEH frame offset so we can use it for
   // llvm.x86.seh.recoverfp.
   StringRef FLinkageName =
-      GlobalValue::getRealLinkageName(MF->getFunction()->getName());
+      GlobalValue::dropLLVMManglingEscape(MF->getFunction()->getName());
   MCSymbol *ParentFrameOffset =
       Ctx.getOrCreateParentFrameOffsetSymbol(FLinkageName);
   const MCExpr *MCOffset =
@@ -635,7 +635,7 @@ void WinException::emitCXXFrameHandler3Table(const MachineFunction *MF) {
   auto &OS = *Asm->OutStreamer;
   const WinEHFuncInfo &FuncInfo = *MF->getWinEHFuncInfo();
 
-  StringRef FuncLinkageName = GlobalValue::getRealLinkageName(F->getName());
+  StringRef FuncLinkageName = GlobalValue::dropLLVMManglingEscape(F->getName());
 
   SmallVector<std::pair<const MCExpr *, int>, 4> IPToStateTable;
   MCSymbol *FuncInfoXData = nullptr;
@@ -942,7 +942,7 @@ void WinException::emitEHRegistrationOffsetLabel(const WinEHFuncInfo &FuncInfo,
 void WinException::emitExceptHandlerTable(const MachineFunction *MF) {
   MCStreamer &OS = *Asm->OutStreamer;
   const Function *F = MF->getFunction();
-  StringRef FLinkageName = GlobalValue::getRealLinkageName(F->getName());
+  StringRef FLinkageName = GlobalValue::dropLLVMManglingEscape(F->getName());
 
   bool VerboseAsm = OS.isVerboseAsm();
   auto AddComment = [&](const Twine &Comment) {

lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp

@@ -5645,7 +5645,7 @@ SelectionDAGBuilder::visitIntrinsicCall(const CallInst &I, unsigned Intrinsic) {
       int FI = FuncInfo.StaticAllocaMap[Slot];
       MCSymbol *FrameAllocSym =
           MF.getMMI().getContext().getOrCreateFrameAllocSymbol(
-              GlobalValue::getRealLinkageName(MF.getName()), Idx);
+              GlobalValue::dropLLVMManglingEscape(MF.getName()), Idx);
       BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, dl,
               TII->get(TargetOpcode::LOCAL_ESCAPE))
           .addSym(FrameAllocSym)
@@ -5666,7 +5666,7 @@ SelectionDAGBuilder::visitIntrinsicCall(const CallInst &I, unsigned Intrinsic) {
     unsigned IdxVal = unsigned(Idx->getLimitedValue(INT_MAX));
     MCSymbol *FrameAllocSym =
         MF.getMMI().getContext().getOrCreateFrameAllocSymbol(
-            GlobalValue::getRealLinkageName(Fn->getName()), IdxVal);
+            GlobalValue::dropLLVMManglingEscape(Fn->getName()), IdxVal);
 
     // Create a MCSymbol for the label to avoid any target lowering
     // that would make this PC relative.

lib/IR/DiagnosticInfo.cpp

@@ -204,7 +204,7 @@ DiagnosticInfoOptimizationBase::Argument::Argument(StringRef Key, const Value *V
   // Only include names that correspond to user variables.  FIXME: we should use
   // debug info if available to get the name of the user variable.
   if (isa<llvm::Argument>(V) || isa<GlobalValue>(V))
-    Val = GlobalValue::getRealLinkageName(V->getName());
+    Val = GlobalValue::dropLLVMManglingEscape(V->getName());
   else if (isa<Constant>(V)) {
     raw_string_ostream OS(Val);
     V->printAsOperand(OS, /*PrintType=*/false);

lib/LTO/LTO.cpp

@@ -973,7 +973,7 @@ Error LTO::runThinLTO(AddStreamFn AddStream, NativeObjectCache Cache,
           // this value. If not, no need to preserve any ThinLTO copies.
           !Res.second.IRName.empty())
         GUIDPreservedSymbols.insert(GlobalValue::getGUID(
-            GlobalValue::getRealLinkageName(Res.second.IRName)));
+            GlobalValue::dropLLVMManglingEscape(Res.second.IRName)));
     }
 
     auto DeadSymbols =
@@ -993,7 +993,7 @@ Error LTO::runThinLTO(AddStreamFn AddStream, NativeObjectCache Cache,
       if (Res.second.IRName.empty())
         continue;
       auto GUID = GlobalValue::getGUID(
-          GlobalValue::getRealLinkageName(Res.second.IRName));
+          GlobalValue::dropLLVMManglingEscape(Res.second.IRName));
       // Mark exported unless index-based analysis determined it to be dead.
       if (!DeadSymbols.count(GUID))
         ExportedGUIDs.insert(GUID);

lib/Target/X86/X86ISelLowering.cpp

@@ -19119,7 +19119,7 @@ static SDValue recoverFramePointer(SelectionDAG &DAG, const Function *Fn,
   // registration, or the .set_setframe offset.
   MCSymbol *OffsetSym =
       MF.getMMI().getContext().getOrCreateParentFrameOffsetSymbol(
-          GlobalValue::getRealLinkageName(Fn->getName()));
+          GlobalValue::dropLLVMManglingEscape(Fn->getName()));
   SDValue OffsetSymVal = DAG.getMCSymbol(OffsetSym, PtrVT);
   SDValue ParentFrameOffset =
       DAG.getNode(ISD::LOCAL_RECOVER, dl, PtrVT, OffsetSymVal);
@@ -19964,7 +19964,7 @@ static SDValue LowerINTRINSIC_WO_CHAIN(SDValue Op, const X86Subtarget &Subtarget
     SDValue Op1 = Op.getOperand(1);
     auto *Fn = cast<Function>(cast<GlobalAddressSDNode>(Op1)->getGlobal());
     MCSymbol *LSDASym = MF.getMMI().getContext().getOrCreateLSDASymbol(
-        GlobalValue::getRealLinkageName(Fn->getName()));
+        GlobalValue::dropLLVMManglingEscape(Fn->getName()));
 
     // Generate a simple absolute symbol reference. This intrinsic is only
     // supported on 32-bit Windows, which isn't PIC.

lib/Target/X86/X86WinEHState.cpp

@@ -398,7 +398,7 @@ Function *WinEHStatePass::generateLSDAInEAXThunk(Function *ParentFunc) {
                         /*isVarArg=*/false);
   Function *Trampoline =
       Function::Create(TrampolineTy, GlobalValue::InternalLinkage,
-                       Twine("__ehhandler$") + GlobalValue::getRealLinkageName(
+                       Twine("__ehhandler$") + GlobalValue::dropLLVMManglingEscape(
                                                    ParentFunc->getName()),
                        TheModule);
   BasicBlock *EntryBB = BasicBlock::Create(Context, "entry", Trampoline);

lib/Transforms/Instrumentation/AddressSanitizer.cpp

@@ -1686,7 +1686,7 @@ AddressSanitizerModule::CreateMetadataGlobal(Module &M, Constant *Initializer,
                      : GlobalVariable::PrivateLinkage;
   GlobalVariable *Metadata = new GlobalVariable(
       M, Initializer->getType(), false, Linkage, Initializer,
-      Twine("__asan_global_") + GlobalValue::getRealLinkageName(OriginalName));
+      Twine("__asan_global_") + GlobalValue::dropLLVMManglingEscape(OriginalName));
   Metadata->setSection(getGlobalMetadataSection());
   return Metadata;
 }