1 files changed, 124 insertions, 8 deletions

diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 59f3e0270571..9ba1a5c25e81 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -710,10 +710,25 @@ void CodeGenModule::Release() {
                               1);
   }
 
-  if (Arch == llvm::Triple::aarch64 || Arch == llvm::Triple::aarch64_32 ||
+  // Add module metadata for return address signing (ignoring
+  // non-leaf/all) and stack tagging. These are actually turned on by function
+  // attributes, but we use module metadata to emit build attributes. This is
+  // needed for LTO, where the function attributes are inside bitcode
+  // serialised into a global variable by the time build attributes are
+  // emitted, so we can't access them.
+  if (Context.getTargetInfo().hasFeature("ptrauth") &&
+      LangOpts.getSignReturnAddressScope() !=
+          LangOptions::SignReturnAddressScopeKind::None)
+    getModule().addModuleFlag(llvm::Module::Override,
+                              "sign-return-address-buildattr", 1);
+  if (LangOpts.Sanitize.has(SanitizerKind::MemTag))
+    getModule().addModuleFlag(llvm::Module::Override,
+                              "tag-stack-memory-buildattr", 1);
+
+  if (Arch == llvm::Triple::thumb || Arch == llvm::Triple::thumbeb ||
+      Arch == llvm::Triple::aarch64 || Arch == llvm::Triple::aarch64_32 ||
       Arch == llvm::Triple::aarch64_be) {
-    getModule().addModuleFlag(llvm::Module::Error,
-                              "branch-target-enforcement",
+    getModule().addModuleFlag(llvm::Module::Error, "branch-target-enforcement",
                               LangOpts.BranchTargetEnforcement);
 
     getModule().addModuleFlag(llvm::Module::Error, "sign-return-address",
@@ -722,9 +737,11 @@ void CodeGenModule::Release() {
     getModule().addModuleFlag(llvm::Module::Error, "sign-return-address-all",
                               LangOpts.isSignReturnAddressScopeAll());
 
-    getModule().addModuleFlag(llvm::Module::Error,
-                              "sign-return-address-with-bkey",
-                              !LangOpts.isSignReturnAddressWithAKey());
+    if (Arch != llvm::Triple::thumb && Arch != llvm::Triple::thumbeb) {
+      getModule().addModuleFlag(llvm::Module::Error,
+                                "sign-return-address-with-bkey",
+                                !LangOpts.isSignReturnAddressWithAKey());
+    }
   }
 
   if (!CodeGenOpts.MemoryProfileOutput.empty()) {
@@ -1266,6 +1283,20 @@ static bool isUniqueInternalLinkageDecl(GlobalDecl GD,
          (CGM.getFunctionLinkage(GD) == llvm::GlobalValue::InternalLinkage);
 }
 
+static void AppendTargetClonesMangling(const CodeGenModule &CGM,
+                                       const TargetClonesAttr *Attr,
+                                       unsigned VersionIndex,
+                                       raw_ostream &Out) {
+  Out << '.';
+  StringRef FeatureStr = Attr->getFeatureStr(VersionIndex);
+  if (FeatureStr.startswith("arch="))
+    Out << "arch_" << FeatureStr.substr(sizeof("arch=") - 1);
+  else
+    Out << FeatureStr;
+
+  Out << '.' << Attr->getMangledIndex(VersionIndex);
+}
+
 static std::string getMangledNameImpl(CodeGenModule &CGM, GlobalDecl GD,
                                       const NamedDecl *ND,
                                       bool OmitMultiVersionMangling = false) {
@@ -1319,6 +1350,10 @@ static std::string getMangledNameImpl(CodeGenModule &CGM, GlobalDecl GD,
       case MultiVersionKind::Target:
         AppendTargetMangling(CGM, FD->getAttr<TargetAttr>(), Out);
         break;
+      case MultiVersionKind::TargetClones:
+        AppendTargetClonesMangling(CGM, FD->getAttr<TargetClonesAttr>(),
+                                   GD.getMultiVersionIndex(), Out);
+        break;
       case MultiVersionKind::None:
         llvm_unreachable("None multiversion type isn't valid here");
       }
@@ -1983,8 +2018,9 @@ bool CodeGenModule::GetCPUAndFeaturesAttributes(GlobalDecl GD,
   FD = FD ? FD->getMostRecentDecl() : FD;
   const auto *TD = FD ? FD->getAttr<TargetAttr>() : nullptr;
   const auto *SD = FD ? FD->getAttr<CPUSpecificAttr>() : nullptr;
+  const auto *TC = FD ? FD->getAttr<TargetClonesAttr>() : nullptr;
   bool AddedAttr = false;
-  if (TD || SD) {
+  if (TD || SD || TC) {
     llvm::StringMap<bool> FeatureMap;
     getContext().getFunctionFeatureMap(FeatureMap, GD);
 
@@ -3226,6 +3262,12 @@ void CodeGenModule::EmitMultiVersionFunctionDefinition(GlobalDecl GD,
     for (unsigned I = 0; I < Spec->cpus_size(); ++I)
       EmitGlobalFunctionDefinition(GD.getWithMultiVersionIndex(I), nullptr);
     // Requires multiple emits.
+  } else if (FD->isTargetClonesMultiVersion()) {
+    auto *Clone = FD->getAttr<TargetClonesAttr>();
+    for (unsigned I = 0; I < Clone->featuresStrs_size(); ++I)
+      if (Clone->isFirstOfVersion(I))
+        EmitGlobalFunctionDefinition(GD.getWithMultiVersionIndex(I), nullptr);
+    EmitTargetClonesResolver(GD);
   } else
     EmitGlobalFunctionDefinition(GD, GV);
 }
@@ -3307,6 +3349,63 @@ llvm::GlobalValue::LinkageTypes getMultiversionLinkage(CodeGenModule &CGM,
   return llvm::GlobalValue::WeakODRLinkage;
 }
 
+void CodeGenModule::EmitTargetClonesResolver(GlobalDecl GD) {
+  const auto *FD = cast<FunctionDecl>(GD.getDecl());
+  assert(FD && "Not a FunctionDecl?");
+  const auto *TC = FD->getAttr<TargetClonesAttr>();
+  assert(TC && "Not a target_clones Function?");
+
+  QualType CanonTy = Context.getCanonicalType(FD->getType());
+  llvm::Type *DeclTy = getTypes().ConvertType(CanonTy);
+
+  if (const auto *CXXFD = dyn_cast<CXXMethodDecl>(FD)) {
+    const CGFunctionInfo &FInfo = getTypes().arrangeCXXMethodDeclaration(CXXFD);
+    DeclTy = getTypes().GetFunctionType(FInfo);
+  }
+
+  llvm::Function *ResolverFunc;
+  if (getTarget().supportsIFunc()) {
+    auto *IFunc = cast<llvm::GlobalIFunc>(
+        GetOrCreateMultiVersionResolver(GD, DeclTy, FD));
+    ResolverFunc = cast<llvm::Function>(IFunc->getResolver());
+  } else
+    ResolverFunc =
+        cast<llvm::Function>(GetOrCreateMultiVersionResolver(GD, DeclTy, FD));
+
+  SmallVector<CodeGenFunction::MultiVersionResolverOption, 10> Options;
+  for (unsigned VersionIndex = 0; VersionIndex < TC->featuresStrs_size();
+       ++VersionIndex) {
+    if (!TC->isFirstOfVersion(VersionIndex))
+      continue;
+    StringRef Version = TC->getFeatureStr(VersionIndex);
+    StringRef MangledName =
+        getMangledName(GD.getWithMultiVersionIndex(VersionIndex));
+    llvm::Constant *Func = GetGlobalValue(MangledName);
+    assert(Func &&
+           "Should have already been created before calling resolver emit");
+
+    StringRef Architecture;
+    llvm::SmallVector<StringRef, 1> Feature;
+
+    if (Version.startswith("arch="))
+      Architecture = Version.drop_front(sizeof("arch=") - 1);
+    else if (Version != "default")
+      Feature.push_back(Version);
+
+    Options.emplace_back(cast<llvm::Function>(Func), Architecture, Feature);
+  }
+
+  const TargetInfo &TI = getTarget();
+  std::stable_sort(
+      Options.begin(), Options.end(),
+      [&TI](const CodeGenFunction::MultiVersionResolverOption &LHS,
+            const CodeGenFunction::MultiVersionResolverOption &RHS) {
+        return TargetMVPriority(TI, LHS) > TargetMVPriority(TI, RHS);
+      });
+  CodeGenFunction CGF(*this);
+  CGF.EmitMultiVersionResolver(ResolverFunc, Options);
+}
+
 void CodeGenModule::emitMultiVersionFunctions() {
   std::vector<GlobalDecl> MVFuncsToEmit;
   MultiVersionFuncs.swap(MVFuncsToEmit);
@@ -3511,8 +3610,25 @@ llvm::Constant *CodeGenModule::GetOrCreateMultiVersionResolver(
   // Since this is the first time we've created this IFunc, make sure
   // that we put this multiversioned function into the list to be
   // replaced later if necessary (target multiversioning only).
-  if (!FD->isCPUDispatchMultiVersion() && !FD->isCPUSpecificMultiVersion())
+  if (FD->isTargetMultiVersion())
     MultiVersionFuncs.push_back(GD);
+  else if (FD->isTargetClonesMultiVersion()) {
+    // In target_clones multiversioning, make sure we emit this if used.
+    auto DDI =
+        DeferredDecls.find(getMangledName(GD.getWithMultiVersionIndex(0)));
+    if (DDI != DeferredDecls.end()) {
+      addDeferredDeclToEmit(GD);
+      DeferredDecls.erase(DDI);
+    } else {
+      // Emit the symbol of the 1st variant, so that the deferred decls know we
+      // need it, otherwise the only global value will be the resolver/ifunc,
+      // which end up getting broken if we search for them with GetGlobalValue'.
+      GetOrCreateLLVMFunction(
+          getMangledName(GD.getWithMultiVersionIndex(0)), DeclTy, FD,
+          /*ForVTable=*/false, /*DontDefer=*/true,
+          /*IsThunk=*/false, llvm::AttributeList(), ForDefinition);
+    }
+  }
 
   if (getTarget().supportsIFunc()) {
     llvm::Type *ResolverType = llvm::FunctionType::get(