[NFC] Move storage of dispatch-version to GlobalDecl

As suggested by Richard Smith, and initially put up for review here:
https://reviews.llvm.org/D53341, this patch removes a hack that was used
to ensure that proper target-feature lists were used when emitting
cpu-dispatch (and eventually, target-clones) implementations. As a part
of this, the GlobalDecl object is proliferated to a bunch more
locations.

Originally, this was put up for review (see above) to get acceptance on
the approach, though discussion with Richard in San Diego showed he
approved of the approach taken here.  Thus, I believe this is acceptable
for Review-After-commit

Differential Revision: https://reviews.llvm.org/D53341

Change-Id: I0a0bd673340d334d93feac789d653e03d9f6b1d5
llvm-svn: 346757

1 files changed, 46 insertions, 47 deletions

diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index d62d8be195d..7b9af628de1 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -891,11 +891,12 @@ static std::string getCPUSpecificMangling(const CodeGenModule &CGM,
 
 static void AppendCPUSpecificCPUDispatchMangling(const CodeGenModule &CGM,
                                                  const CPUSpecificAttr *Attr,
+                                                 unsigned CPUIndex,
                                                  raw_ostream &Out) {
   // cpu_specific gets the current name, dispatch gets the resolver if IFunc is
   // supported.
   if (Attr)
-    Out << getCPUSpecificMangling(CGM, Attr->getCurCPUName()->getName());
+    Out << getCPUSpecificMangling(CGM, Attr->getCPUName(CPUIndex)->getName());
   else if (CGM.getTarget().supportsIFunc())
     Out << ".resolver";
 }
@@ -963,8 +964,9 @@ static std::string getMangledNameImpl(const CodeGenModule &CGM, GlobalDecl GD,
   if (const auto *FD = dyn_cast<FunctionDecl>(ND))
     if (FD->isMultiVersion() && !OmitMultiVersionMangling) {
       if (FD->isCPUDispatchMultiVersion() || FD->isCPUSpecificMultiVersion())
-        AppendCPUSpecificCPUDispatchMangling(
-            CGM, FD->getAttr<CPUSpecificAttr>(), Out);
+        AppendCPUSpecificCPUDispatchMangling(CGM,
+                                             FD->getAttr<CPUSpecificAttr>(),
+                                             GD.getMultiVersionIndex(), Out);
       else
         AppendTargetMangling(CGM, FD->getAttr<TargetAttr>(), Out);
     }
@@ -1024,26 +1026,6 @@ StringRef CodeGenModule::getMangledName(GlobalDecl GD) {
     }
   }
 
-  const auto *FD = dyn_cast<FunctionDecl>(GD.getDecl());
-  // Since CPUSpecific can require multiple emits per decl, store the manglings
-  // separately.
-  if (FD &&
-      (FD->isCPUDispatchMultiVersion() || FD->isCPUSpecificMultiVersion())) {
-    const auto *SD = FD->getAttr<CPUSpecificAttr>();
-
-    std::pair<GlobalDecl, unsigned> SpecCanonicalGD{
-        CanonicalGD,
-        SD ? SD->ActiveArgIndex : std::numeric_limits<unsigned>::max()};
-
-    auto FoundName = CPUSpecificMangledDeclNames.find(SpecCanonicalGD);
-    if (FoundName != CPUSpecificMangledDeclNames.end())
-      return FoundName->second;
-
-    auto Result = CPUSpecificManglings.insert(
-        std::make_pair(getMangledNameImpl(*this, GD, FD), SpecCanonicalGD));
-    return CPUSpecificMangledDeclNames[SpecCanonicalGD] = Result.first->first();
-  }
-
   auto FoundName = MangledDeclNames.find(CanonicalGD);
   if (FoundName != MangledDeclNames.end())
     return FoundName->second;
@@ -1166,12 +1148,12 @@ llvm::ConstantInt *CodeGenModule::CreateCrossDsoCfiTypeId(llvm::Metadata *MD) {
   return llvm::ConstantInt::get(Int64Ty, llvm::MD5Hash(MDS->getString()));
 }
 
-void CodeGenModule::SetLLVMFunctionAttributes(const Decl *D,
+void CodeGenModule::SetLLVMFunctionAttributes(GlobalDecl GD,
                                               const CGFunctionInfo &Info,
                                               llvm::Function *F) {
   unsigned CallingConv;
   llvm::AttributeList PAL;
-  ConstructAttributeList(F->getName(), Info, D, PAL, CallingConv, false);
+  ConstructAttributeList(F->getName(), Info, GD, PAL, CallingConv, false);
   F->setAttributes(PAL);
   F->setCallingConv(static_cast<llvm::CallingConv::ID>(CallingConv));
 }
@@ -1393,21 +1375,21 @@ void CodeGenModule::SetCommonAttributes(GlobalDecl GD, llvm::GlobalValue *GV) {
   }
 }
 
-bool CodeGenModule::GetCPUAndFeaturesAttributes(const Decl *D,
+bool CodeGenModule::GetCPUAndFeaturesAttributes(GlobalDecl GD,
                                                 llvm::AttrBuilder &Attrs) {
   // Add target-cpu and target-features attributes to functions. If
   // we have a decl for the function and it has a target attribute then
   // parse that and add it to the feature set.
   StringRef TargetCPU = getTarget().getTargetOpts().CPU;
   std::vector<std::string> Features;
-  const auto *FD = dyn_cast_or_null<FunctionDecl>(D);
+  const auto *FD = dyn_cast_or_null<FunctionDecl>(GD.getDecl());
   FD = FD ? FD->getMostRecentDecl() : FD;
   const auto *TD = FD ? FD->getAttr<TargetAttr>() : nullptr;
   const auto *SD = FD ? FD->getAttr<CPUSpecificAttr>() : nullptr;
   bool AddedAttr = false;
   if (TD || SD) {
     llvm::StringMap<bool> FeatureMap;
-    getFunctionFeatureMap(FeatureMap, FD);
+    getFunctionFeatureMap(FeatureMap, GD);
 
     // Produce the canonical string for this set of features.
     for (const llvm::StringMap<bool>::value_type &Entry : FeatureMap)
@@ -1463,7 +1445,7 @@ void CodeGenModule::setNonAliasAttributes(GlobalDecl GD,
           F->addFnAttr("implicit-section-name", SA->getName());
 
       llvm::AttrBuilder Attrs;
-      if (GetCPUAndFeaturesAttributes(D, Attrs)) {
+      if (GetCPUAndFeaturesAttributes(GD, Attrs)) {
         // We know that GetCPUAndFeaturesAttributes will always have the
         // newest set, since it has the newest possible FunctionDecl, so the
         // new ones should replace the old.
@@ -1486,7 +1468,7 @@ void CodeGenModule::SetInternalFunctionAttributes(GlobalDecl GD,
                                                   llvm::Function *F,
                                                   const CGFunctionInfo &FI) {
   const Decl *D = GD.getDecl();
-  SetLLVMFunctionAttributes(D, FI, F);
+  SetLLVMFunctionAttributes(GD, FI, F);
   SetLLVMFunctionAttributesForDefinition(D, F);
 
   F->setLinkage(llvm::Function::InternalLinkage);
@@ -1548,7 +1530,7 @@ void CodeGenModule::SetFunctionAttributes(GlobalDecl GD, llvm::Function *F,
   const auto *FD = cast<FunctionDecl>(GD.getDecl());
 
   if (!IsIncompleteFunction) {
-    SetLLVMFunctionAttributes(FD, getTypes().arrangeGlobalDeclaration(GD), F);
+    SetLLVMFunctionAttributes(GD, getTypes().arrangeGlobalDeclaration(GD), F);
     // Setup target-specific attributes.
     if (F->isDeclaration())
       getTargetCodeGenInfo().setTargetAttributes(FD, F, *this);
@@ -2424,6 +2406,19 @@ bool CodeGenModule::shouldOpportunisticallyEmitVTables() {
   return CodeGenOpts.OptimizationLevel > 0;
 }
 
+void CodeGenModule::EmitMultiVersionFunctionDefinition(GlobalDecl GD,
+                                                       llvm::GlobalValue *GV) {
+  const auto *FD = cast<FunctionDecl>(GD.getDecl());
+
+  if (FD->isCPUSpecificMultiVersion()) {
+    auto *Spec = FD->getAttr<CPUSpecificAttr>();
+    for (unsigned I = 0; I < Spec->cpus_size(); ++I)
+      EmitGlobalFunctionDefinition(GD.getWithMultiVersionIndex(I), nullptr);
+    // Requires multiple emits.
+  } else
+    EmitGlobalFunctionDefinition(GD, GV);
+}
+
 void CodeGenModule::EmitGlobalDefinition(GlobalDecl GD, llvm::GlobalValue *GV) {
   const auto *D = cast<ValueDecl>(GD.getDecl());
 
@@ -2431,7 +2426,7 @@ void CodeGenModule::EmitGlobalDefinition(GlobalDecl GD, llvm::GlobalValue *GV) {
                                  Context.getSourceManager(),
                                  "Generating code for declaration");
 
-  if (isa<FunctionDecl>(D)) {
+  if (const auto *FD = dyn_cast<FunctionDecl>(D)) {
     // At -O0, don't generate IR for functions with available_externally
     // linkage.
     if (!shouldEmitFunction(GD))
@@ -2444,6 +2439,8 @@ void CodeGenModule::EmitGlobalDefinition(GlobalDecl GD, llvm::GlobalValue *GV) {
         ABI->emitCXXStructor(CD, getFromCtorType(GD.getCtorType()));
       else if (const auto *DD = dyn_cast<CXXDestructorDecl>(Method))
         ABI->emitCXXStructor(DD, getFromDtorType(GD.getDtorType()));
+      else if (FD->isMultiVersion())
+        EmitMultiVersionFunctionDefinition(GD, GV);
       else
         EmitGlobalFunctionDefinition(GD, GV);
 
@@ -2453,6 +2450,8 @@ void CodeGenModule::EmitGlobalDefinition(GlobalDecl GD, llvm::GlobalValue *GV) {
       return;
     }
 
+    if (FD->isMultiVersion())
+      return EmitMultiVersionFunctionDefinition(GD, GV);
     return EmitGlobalFunctionDefinition(GD, GV);
   }
 
@@ -2566,13 +2565,20 @@ void CodeGenModule::emitCPUDispatchDefinition(GlobalDecl GD) {
 
   SmallVector<CodeGenFunction::MultiVersionResolverOption, 10> Options;
   const TargetInfo &Target = getTarget();
+  unsigned Index = 0;
   for (const IdentifierInfo *II : DD->cpus()) {
     // Get the name of the target function so we can look it up/create it.
     std::string MangledName = getMangledNameImpl(*this, GD, FD, true) +
                               getCPUSpecificMangling(*this, II->getName());
-    llvm::Constant *Func = GetOrCreateLLVMFunction(
-        MangledName, DeclTy, GD, /*ForVTable=*/false, /*DontDefer=*/true,
-        /*IsThunk=*/false, llvm::AttributeList(), ForDefinition);
+
+    llvm::Constant *Func = GetGlobalValue(MangledName);
+
+    if (!Func)
+      Func = GetOrCreateLLVMFunction(
+          MangledName, DeclTy, GD.getWithMultiVersionIndex(Index),
+          /*ForVTable=*/false, /*DontDefer=*/true,
+          /*IsThunk=*/false, llvm::AttributeList(), ForDefinition);
+
     llvm::SmallVector<StringRef, 32> Features;
     Target.getCPUSpecificCPUDispatchFeatures(II->getName(), Features);
     llvm::transform(Features, Features.begin(),
@@ -2582,6 +2588,7 @@ void CodeGenModule::emitCPUDispatchDefinition(GlobalDecl GD) {
           return !Target.validateCpuSupports(Feat);
         }), Features.end());
     Options.emplace_back(cast<llvm::Function>(Func), StringRef{}, Features);
+    ++Index;
   }
 
   llvm::sort(
@@ -3974,15 +3981,6 @@ void CodeGenModule::EmitGlobalFunctionDefinition(GlobalDecl GD,
     AddGlobalDtor(Fn, DA->getPriority());
   if (D->hasAttr<AnnotateAttr>())
     AddGlobalAnnotations(D, Fn);
-
-  if (D->isCPUSpecificMultiVersion()) {
-    auto *Spec = D->getAttr<CPUSpecificAttr>();
-    // If there is another specific version we need to emit, do so here.
-    if (Spec->ActiveArgIndex + 1 < Spec->cpus_size()) {
-      ++Spec->ActiveArgIndex;
-      EmitGlobalFunctionDefinition(GD, nullptr);
-    }
-  }
 }
 
 void CodeGenModule::EmitAliasDefinition(GlobalDecl GD) {
@@ -5404,8 +5402,9 @@ TargetAttr::ParsedTargetAttr CodeGenModule::filterFunctionTargetAttrs(const Targ
 // Fills in the supplied string map with the set of target features for the
 // passed in function.
 void CodeGenModule::getFunctionFeatureMap(llvm::StringMap<bool> &FeatureMap,
-                                          const FunctionDecl *FD) {
+                                          GlobalDecl GD) {
   StringRef TargetCPU = Target.getTargetOpts().CPU;
+  const FunctionDecl *FD = GD.getDecl()->getAsFunction();
   if (const auto *TD = FD->getAttr<TargetAttr>()) {
     TargetAttr::ParsedTargetAttr ParsedAttr = filterFunctionTargetAttrs(TD);
 
@@ -5427,8 +5426,8 @@ void CodeGenModule::getFunctionFeatureMap(llvm::StringMap<bool> &FeatureMap,
                           ParsedAttr.Features);
   } else if (const auto *SD = FD->getAttr<CPUSpecificAttr>()) {
     llvm::SmallVector<StringRef, 32> FeaturesTmp;
-    Target.getCPUSpecificCPUDispatchFeatures(SD->getCurCPUName()->getName(),
-                                             FeaturesTmp);
+    Target.getCPUSpecificCPUDispatchFeatures(
+        SD->getCPUName(GD.getMultiVersionIndex())->getName(), FeaturesTmp);
     std::vector<std::string> Features(FeaturesTmp.begin(), FeaturesTmp.end());
     Target.initFeatureMap(FeatureMap, getDiags(), TargetCPU, Features);
   } else {