Simplify AttrBuilder storage for target dependent attributes

[serge-sans-paille]

Summary

Using and std::map<SmallString, SmallString> for target dependent attributes is inefficient: it makes its constructor slightly heavier, and involves extra allocation for each new string attribute. Storing the attribute key/value as strings implies extra allocation/copy step.

Use a sorted vector instead. Given the low number of attributes generally involved, this is cheaper, as showcased by https://llvm-compile-time-tracker.com/compare.php?from=5de322295f4ade692dc4f1823ae4450ad3c48af2&to=05bc480bf641a9e3b466619af43a2d123ee3f71d&stat=instructions

[serge-sans-paille]

upload correct patch version

[nikic]

I'm generally on board with this change. After D116110, the AttrBuilder is only used in situations where we actually expect all the added attributes to be converted to Attributes in any case, so we don't lose anything by storing them directly in that form. At the same time, we don't need to do expensive conversions from Attribute to internal AttrBuilder representation and back to Attribute (involving FoldingSet lookups) when AttrBuilder is constructed from an existing AttributeList/AttributeSet. This is common, because the general approach to attribute modification is "dump everything into AttrBuilder, add new attributes, convert back to AttributeSet".

The main externality here is that AttrBuilder now requires an LLVMContext, but it doesn't look like obtaining one is a problem for any existing usage. I do think it would be good to land the LLVMContext constructor argument addition in a separate patch from the internal representation change, as that one is essentially just busywork.

I've left some implementation nits...

llvm/include/llvm/IR/Attributes.h

1006

Don't think this needs to be in the header.

1008

LLVMContext &Ctx here and elsewhere.

llvm/lib/AsmParser/LLParser.cpp

1240–1241

I'd split the if here and store the AttrBuilder in a variable and then reuse below. Getting a bit hard to read.

llvm/lib/IR/Attributes.cpp

1626

This method move looks a bit weird, I'd leave it where it was so we don't mix add/remove.

1771

Could be more specific here, e.g. TODO: Could merge both lists in one loop.

1778–1779

Unrelated to this change, but with AttributeMask this FIXME no longer makes sense.

1838

I'd combine the Attrs == B.Attrs check into this return as well, so it doesn't feel lonely :)

[rnk]

Nice!

[serge-sans-paille]

Take advice into account

[nikic]

LG from my side, but I'd like a second opinion for the "require LLVMContext in AttrBuilder" part of the change, as that's the main API impact.

llvm/lib/AsmParser/LLParser.cpp

136

These M->getContext() can be replaced by just Context, as LLParser stores a reference to that.

1246

Is the separate find call here to avoid constructing AttrBuilder if it's already in the map?

I was going to suggest that you can write this as R = NumberedAttrBuilders.emplace(VarID, M->getContext()).first; and leave the construction of AttrBuilder to emplace(), but it turns out that emplace() still unconditionally constructs the object (because C++) and the sensible replacement for this (try_emplace) has only been introduced in C++17.

llvm/lib/IR/Attributes.cpp

1789–1790

We might as well directly resolve this TODO, I think it should be as simple as:

erase_if(TargetDepAttrs, [&](Attribute A) { return AM.contains(A); });

[rnk]

In D116599#3221724, @nikic wrote:

LG from my side, but I'd like a second opinion for the "require LLVMContext in AttrBuilder" part of the change, as that's the main API impact.

I think every non-toy frontend for LLVM probably uses the AttrBuilder API to construct attributes, so it's a pretty broad impact. However, I don't see a good way around it, and I think the improvements to string attribute handling are worth taking the API break.

I will say that the Google was recently affected by the opaque pointer IRBuilder API removal (rG89eb85ac6ea), and the ability to pre-migrate code to the new API was very valuable. At least in our usage, where we progressively pick new LLVM versions, it would be helpful to land a no-op AttrBuilder constructor that takes and ignores an LLVMContext. I don't know how common that usage model is for others.

[serge-sans-paille]

Minor updates

clang/lib/CodeGen/CGAtomic.cpp

 
 static RValue emitAtomicLibcall(CodeGenFunction &CGF,
                                 StringRef fnName,
                                 QualType resultType,
                                 CallArgList &args) {
   const CGFunctionInfo &fnInfo =
     CGF.CGM.getTypes().arrangeBuiltinFunctionCall(resultType, args);
   llvm::FunctionType *fnTy = CGF.CGM.getTypes().GetFunctionType(fnInfo);
-  llvm::AttrBuilder fnAttrB;
+  llvm::AttrBuilder fnAttrB(CGF.getLLVMContext());
   fnAttrB.addAttribute(llvm::Attribute::NoUnwind);
   fnAttrB.addAttribute(llvm::Attribute::WillReturn);
   llvm::AttributeList fnAttrs = llvm::AttributeList::get(
       CGF.getLLVMContext(), llvm::AttributeList::FunctionIndex, fnAttrB);
 
   llvm::FunctionCallee fn =
       CGF.CGM.CreateRuntimeFunction(fnTy, fnName, fnAttrs);
   auto callee = CGCallee::forDirect(fn);

clang/lib/CodeGen/CGBuiltin.cpp

if (NumArgs == 4) {
 
       auto Info =
           CGM.getOpenCLRuntime().emitOpenCLEnqueuedBlock(*this, E->getArg(3));
       llvm::Value *Kernel =
           Builder.CreatePointerCast(Info.Kernel, GenericVoidPtrTy);
       llvm::Value *Block =
           Builder.CreatePointerCast(Info.BlockArg, GenericVoidPtrTy);
 
-      AttrBuilder B;
+      AttrBuilder B(Builder.getContext());
       B.addByValAttr(NDRangeL.getAddress(*this).getElementType());
       llvm::AttributeList ByValAttrSet =
           llvm::AttributeList::get(CGM.getModule().getContext(), 3U, B);
 
       auto RTCall =
           EmitRuntimeCall(CGM.CreateRuntimeFunction(FTy, Name, ByValAttrSet),
                           {Queue, Flags, Range, Kernel, Block});
       RTCall->setAttributes(ByValAttrSet);

clang/lib/CodeGen/CGCall.cpp

void CodeGenModule::getDefaultFunctionAttributes(StringRef Name,
   for (StringRef Attr : CodeGenOpts.DefaultFunctionAttrs) {
     StringRef Var, Value;
     std::tie(Var, Value) = Attr.split('=');
     FuncAttrs.addAttribute(Var, Value);
   }
 }
 
 void CodeGenModule::addDefaultFunctionDefinitionAttributes(llvm::Function &F) {
-  llvm::AttrBuilder FuncAttrs;
+  llvm::AttrBuilder FuncAttrs(F.getContext());
   getDefaultFunctionAttributes(F.getName(), F.hasOptNone(),
                                /* AttrOnCallSite = */ false, FuncAttrs);
   // TODO: call GetCPUAndFeaturesAttributes?
   F.addFnAttrs(FuncAttrs);
 }
 
 void CodeGenModule::addDefaultFunctionDefinitionAttributes(
                                                    llvm::AttrBuilder &attrs) {

 ///     added here rather than getDefaultFunctionAttributes.
 ///
 void CodeGenModule::ConstructAttributeList(StringRef Name,
                                            const CGFunctionInfo &FI,
                                            CGCalleeInfo CalleeInfo,
                                            llvm::AttributeList &AttrList,
                                            unsigned &CallingConv,
                                            bool AttrOnCallSite, bool IsThunk) {
-  llvm::AttrBuilder FuncAttrs;
-  llvm::AttrBuilder RetAttrs;
+  llvm::AttrBuilder FuncAttrs(getLLVMContext());
+  llvm::AttrBuilder RetAttrs(getLLVMContext());
 
   // Collect function IR attributes from the CC lowering.
   // We'll collect the paramete and result attributes later.
   CallingConv = FI.getEffectiveCallingConvention();
   if (FI.isNoReturn())
     FuncAttrs.addAttribute(llvm::Attribute::NoReturn);
   if (FI.isCmseNSCall())
     FuncAttrs.addAttribute("cmse_nonsecure_call");
if (!IsThunk) {
     }
   }
 
   bool hasUsedSRet = false;
   SmallVector<llvm::AttributeSet, 4> ArgAttrs(IRFunctionArgs.totalIRArgs());
 
   // Attach attributes to sret.
   if (IRFunctionArgs.hasSRetArg()) {
-    llvm::AttrBuilder SRETAttrs;
+    llvm::AttrBuilder SRETAttrs(getLLVMContext());
     SRETAttrs.addStructRetAttr(getTypes().ConvertTypeForMem(RetTy));
     hasUsedSRet = true;
     if (RetAI.getInReg())
       SRETAttrs.addAttribute(llvm::Attribute::InReg);
     SRETAttrs.addAlignmentAttr(RetAI.getIndirectAlign().getQuantity());
     ArgAttrs[IRFunctionArgs.getSRetArgNo()] =
         llvm::AttributeSet::get(getLLVMContext(), SRETAttrs);
   }
 
   // Attach attributes to inalloca argument.
   if (IRFunctionArgs.hasInallocaArg()) {
-    llvm::AttrBuilder Attrs;
+    llvm::AttrBuilder Attrs(getLLVMContext());
     Attrs.addInAllocaAttr(FI.getArgStruct());
     ArgAttrs[IRFunctionArgs.getInallocaArgNo()] =
         llvm::AttributeSet::get(getLLVMContext(), Attrs);
   }
 
   // Apply `nonnull`, `dereferencable(N)` and `align N` to the `this` argument,
   // unless this is a thunk function.
   // FIXME: fix this properly, https://reviews.llvm.org/D100388
   if (FI.isInstanceMethod() && !IRFunctionArgs.hasInallocaArg() &&
       !FI.arg_begin()->type->isVoidPointerType() && !IsThunk) {
     auto IRArgs = IRFunctionArgs.getIRArgs(0);
 
     assert(IRArgs.second == 1 && "Expected only a single `this` pointer.");
 
-    llvm::AttrBuilder Attrs;
+    llvm::AttrBuilder Attrs(getLLVMContext());
 
     QualType ThisTy =
         FI.arg_begin()->type.castAs<PointerType>()->getPointeeType();
 
     if (!CodeGenOpts.NullPointerIsValid &&
         getContext().getTargetAddressSpace(FI.arg_begin()->type) == 0) {
       Attrs.addAttribute(llvm::Attribute::NonNull);
       Attrs.addDereferenceableAttr(getMinimumObjectSize(ThisTy).getQuantity());
void CodeGenModule::ConstructAttributeList(StringRef Name,
   }
 
   unsigned ArgNo = 0;
   for (CGFunctionInfo::const_arg_iterator I = FI.arg_begin(),
                                           E = FI.arg_end();
        I != E; ++I, ++ArgNo) {
     QualType ParamType = I->type;
     const ABIArgInfo &AI = I->info;
-    llvm::AttrBuilder Attrs;
+    llvm::AttrBuilder Attrs(getLLVMContext());
 
     // Add attribute for padding argument, if necessary.
     if (IRFunctionArgs.hasPaddingArg(ArgNo)) {
       if (AI.getPaddingInReg()) {
         ArgAttrs[IRFunctionArgs.getPaddingArgNo(ArgNo)] =
             llvm::AttributeSet::get(
                 getLLVMContext(),
-                llvm::AttrBuilder().addAttribute(llvm::Attribute::InReg));
+                llvm::AttrBuilder(getLLVMContext()).addAttribute(llvm::Attribute::InReg));
       }
     }
 
     // Decide whether the argument we're handling could be partially undef
     bool ArgNoUndef = DetermineNoUndef(ParamType, getTypes(), DL, AI);
     if (CodeGenOpts.EnableNoundefAttrs && ArgNoUndef)
       Attrs.addAttribute(llvm::Attribute::NoUndef);
 
case ABIArgInfo::Direct: {
             // A C99 array parameter declaration with the static keyword also
             // indicates dereferenceability, and if the size is constant we can
             // use the dereferenceable attribute (which requires the size in
             // bytes).
             if (ArrTy->getSizeModifier() == ArrayType::Static) {
               QualType ETy = ArrTy->getElementType();
               llvm::Align Alignment =
                   CGM.getNaturalTypeAlignment(ETy).getAsAlign();
-              AI->addAttrs(llvm::AttrBuilder().addAlignmentAttr(Alignment));
+              AI->addAttrs(llvm::AttrBuilder(getLLVMContext()).addAlignmentAttr(Alignment));
               uint64_t ArrSize = ArrTy->getSize().getZExtValue();
               if (!ETy->isIncompleteType() && ETy->isConstantSizeType() &&
                   ArrSize) {
-                llvm::AttrBuilder Attrs;
+                llvm::AttrBuilder Attrs(getLLVMContext());
                 Attrs.addDereferenceableAttr(
                     getContext().getTypeSizeInChars(ETy).getQuantity() *
                     ArrSize);
                 AI->addAttrs(Attrs);
               } else if (getContext().getTargetInfo().getNullPointerValue(
                              ETy.getAddressSpace()) == 0 &&
                          !CGM.getCodeGenOpts().NullPointerIsValid) {
                 AI->addAttr(llvm::Attribute::NonNull);
               }
             }
           } else if (const auto *ArrTy =
                      getContext().getAsVariableArrayType(OTy)) {
             // For C99 VLAs with the static keyword, we don't know the size so
             // we can't use the dereferenceable attribute, but in addrspace(0)
             // we know that it must be nonnull.
             if (ArrTy->getSizeModifier() == VariableArrayType::Static) {
               QualType ETy = ArrTy->getElementType();
               llvm::Align Alignment =
                   CGM.getNaturalTypeAlignment(ETy).getAsAlign();
-              AI->addAttrs(llvm::AttrBuilder().addAlignmentAttr(Alignment));
+              AI->addAttrs(llvm::AttrBuilder(getLLVMContext()).addAlignmentAttr(Alignment));
               if (!getContext().getTargetAddressSpace(ETy) &&
                   !CGM.getCodeGenOpts().NullPointerIsValid)
                 AI->addAttr(llvm::Attribute::NonNull);
             }
           }
 
           // Set `align` attribute if any.
           const auto *AVAttr = PVD->getAttr<AlignValueAttr>();
           if (!AVAttr)
             if (const auto *TOTy = dyn_cast<TypedefType>(OTy))
               AVAttr = TOTy->getDecl()->getAttr<AlignValueAttr>();
           if (AVAttr && !SanOpts.has(SanitizerKind::Alignment)) {
             // If alignment-assumption sanitizer is enabled, we do *not* add
             // alignment attribute here, but emit normal alignment assumption,
             // so the UBSAN check could function.
             llvm::ConstantInt *AlignmentCI =
                 cast<llvm::ConstantInt>(EmitScalarExpr(AVAttr->getAlignment()));
             uint64_t AlignmentInt =
                 AlignmentCI->getLimitedValue(llvm::Value::MaximumAlignment);
             if (AI->getParamAlign().valueOrOne() < AlignmentInt) {
               AI->removeAttr(llvm::Attribute::AttrKind::Alignment);
-              AI->addAttrs(llvm::AttrBuilder().addAlignmentAttr(
+              AI->addAttrs(llvm::AttrBuilder(getLLVMContext()).addAlignmentAttr(
                   llvm::Align(AlignmentInt)));
             }
           }
         }
 
         // Set 'noalias' if an argument type has the `restrict` qualifier.
         if (Arg->getType().isRestrictQualified())
           AI->addAttr(llvm::Attribute::NoAlias);

clang/lib/CodeGen/CGExpr.cpp

if (CheckInfo.Version && !MinimalRuntime)
     FnName += "_v" + llvm::utostr(CheckInfo.Version);
   if (MinimalRuntime)
     FnName += "_minimal";
   if (NeedsAbortSuffix)
     FnName += "_abort";
   bool MayReturn =
       !IsFatal || RecoverKind == CheckRecoverableKind::AlwaysRecoverable;
 
-  llvm::AttrBuilder B;
+  llvm::AttrBuilder B(CGF.getLLVMContext());
   if (!MayReturn) {
     B.addAttribute(llvm::Attribute::NoReturn)
         .addAttribute(llvm::Attribute::NoUnwind);
   }
   B.addAttribute(llvm::Attribute::UWTable);
 
   llvm::FunctionCallee Fn = CGF.CGM.CreateRuntimeFunction(
       FnType, FnName,

clang/lib/CodeGen/CodeGenModule.cpp

for (const CXXBaseSpecifier &B : RD->bases())
       CollectMostBases(B.getType()->getAsCXXRecordDecl());
   };
   CollectMostBases(RD);
   return MostBases.takeVector();
 }
 
 void CodeGenModule::SetLLVMFunctionAttributesForDefinition(const Decl *D,
                                                            llvm::Function *F) {
-  llvm::AttrBuilder B;
+  llvm::AttrBuilder B(F->getContext());
 
   if (CodeGenOpts.UnwindTables)
     B.addAttribute(llvm::Attribute::UWTable);
 
   if (CodeGenOpts.StackClashProtector)
     B.addAttribute("probe-stack", "inline-asm");
 
   if (!hasUnwindExceptions(LangOpts))
for (const CXXRecordDecl *Base : getMostBaseClasses(MD->getParent())) {
       F->addTypeMetadata(0, Id);
     }
   }
 }
 
 void CodeGenModule::setLLVMFunctionFEnvAttributes(const FunctionDecl *D,
                                                   llvm::Function *F) {
   if (D->hasAttr<StrictFPAttr>()) {
-    llvm::AttrBuilder FuncAttrs;
+    llvm::AttrBuilder FuncAttrs(F->getContext());
     FuncAttrs.addAttribute("strictfp");
     F->addFnAttrs(FuncAttrs);
   }
 }
 
 void CodeGenModule::SetCommonAttributes(GlobalDecl GD, llvm::GlobalValue *GV) {
   const Decl *D = GD.getDecl();
   if (isa_and_nonnull<NamedDecl>(D))
if (D) {
 
     if (auto *F = dyn_cast<llvm::Function>(GO)) {
       if (D->hasAttr<RetainAttr>())
         addUsedGlobal(F);
       if (auto *SA = D->getAttr<PragmaClangTextSectionAttr>())
         if (!D->getAttr<SectionAttr>())
           F->addFnAttr("implicit-section-name", SA->getName());
 
-      llvm::AttrBuilder Attrs;
+      llvm::AttrBuilder Attrs(F->getContext());
       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.
         llvm::AttributeMask RemoveAttrs;
         RemoveAttrs.addAttribute("target-cpu");
         RemoveAttrs.addAttribute("target-features");
         RemoveAttrs.addAttribute("tune-cpu");
llvm::Constant *BC = llvm::ConstantExpr::getBitCast(
         F, Entry->getValueType()->getPointerTo());
     addGlobalValReplacement(Entry, BC);
   }
 
   assert(F->getName() == MangledName && "name was uniqued!");
   if (D)
     SetFunctionAttributes(GD, F, IsIncompleteFunction, IsThunk);
   if (ExtraAttrs.hasFnAttrs()) {
-    llvm::AttrBuilder B(ExtraAttrs, llvm::AttributeList::FunctionIndex);
+    llvm::AttrBuilder B(F->getContext(), ExtraAttrs, llvm::AttributeList::FunctionIndex);
     F->addFnAttrs(B);
   }
 
   if (!DontDefer) {
     // All MSVC dtors other than the base dtor are linkonce_odr and delegate to
     // each other bottoming out with the base dtor.  Therefore we emit non-base
     // dtors on usage, even if there is no dtor definition in the TU.
     if (D && isa<CXXDestructorDecl>(D) &&

clang/lib/CodeGen/TargetInfo.cpp

explicit WebAssemblyTargetCodeGenInfo(CodeGen::CodeGenTypes &CGT,
       : TargetCodeGenInfo(std::make_unique<WebAssemblyABIInfo>(CGT, K)) {}
 
   void setTargetAttributes(const Decl *D, llvm::GlobalValue *GV,
                            CodeGen::CodeGenModule &CGM) const override {
     TargetCodeGenInfo::setTargetAttributes(D, GV, CGM);
     if (const auto *FD = dyn_cast_or_null<FunctionDecl>(D)) {
       if (const auto *Attr = FD->getAttr<WebAssemblyImportModuleAttr>()) {
         llvm::Function *Fn = cast<llvm::Function>(GV);
-        llvm::AttrBuilder B;
+        llvm::AttrBuilder B(GV->getContext());
         B.addAttribute("wasm-import-module", Attr->getImportModule());
         Fn->addFnAttrs(B);
       }
       if (const auto *Attr = FD->getAttr<WebAssemblyImportNameAttr>()) {
         llvm::Function *Fn = cast<llvm::Function>(GV);
-        llvm::AttrBuilder B;
+        llvm::AttrBuilder B(GV->getContext());
         B.addAttribute("wasm-import-name", Attr->getImportName());
         Fn->addFnAttrs(B);
       }
       if (const auto *Attr = FD->getAttr<WebAssemblyExportNameAttr>()) {
         llvm::Function *Fn = cast<llvm::Function>(GV);
-        llvm::AttrBuilder B;
+        llvm::AttrBuilder B(GV->getContext());
         B.addAttribute("wasm-export-name", Attr->getExportName());
         Fn->addFnAttrs(B);
       }
     }
 
     if (auto *FD = dyn_cast_or_null<FunctionDecl>(D)) {
       llvm::Function *Fn = cast<llvm::Function>(GV);
       if (!FD->doesThisDeclarationHaveABody() && !FD->hasPrototype())
void setTargetAttributes(const Decl *D, llvm::GlobalValue *GV,
 
     ARMABIInfo::ABIKind ABI = cast<ARMABIInfo>(getABIInfo()).getABIKind();
     if (ABI == ARMABIInfo::APCS)
       return;
 
     // AAPCS guarantees that sp will be 8-byte aligned on any public interface,
     // however this is not necessarily true on taking any interrupt. Instruct
     // the backend to perform a realignment as part of the function prologue.
-    llvm::AttrBuilder B;
+    llvm::AttrBuilder B(Fn->getContext());
     B.addStackAlignmentAttr(8);
     Fn->addFnAttrs(B);
   }
 };
 
 class WindowsARMTargetCodeGenInfo : public ARMTargetCodeGenInfo {
 public:
   WindowsARMTargetCodeGenInfo(CodeGenTypes &CGT, ARMABIInfo::ABIKind K)

llvm/include/llvm/CodeGen/IndirectThunks.h

Function *F = Function::Create(Type,
                                  Name, &M);
   if (Comdat) {
     F->setVisibility(GlobalValue::HiddenVisibility);
     F->setComdat(M.getOrInsertComdat(Name));
   }
 
   // Add Attributes so that we don't create a frame, unwind information, or
   // inline.
-  AttrBuilder B;
+  AttrBuilder B(Ctx);
   B.addAttribute(llvm::Attribute::NoUnwind);
   B.addAttribute(llvm::Attribute::Naked);
   F->addFnAttrs(B);
 
   // Populate our function a bit so that we can verify.
   BasicBlock *Entry = BasicBlock::Create(Ctx, "entry", F);
   IRBuilder<> Builder(Entry);
 

llvm/include/llvm/IR/Attributes.h

 
 //===----------------------------------------------------------------------===//
 /// \class
 /// This class is used in conjunction with the Attribute::get method to
 /// create an Attribute object. The object itself is uniquified. The Builder's
 /// value, however, is not. So this can be used as a quick way to test for
 /// equality, presence of attributes, etc.
 class AttrBuilder {
+  LLVMContext &Ctx;
   std::bitset<Attribute::EndAttrKinds> Attrs;
-  std::map<SmallString<32>, SmallString<32>, std::less<>> TargetDepAttrs;
+  SmallVector<Attribute, 8> TargetDepAttrs;
   std::array<uint64_t, Attribute::NumIntAttrKinds> IntAttrs = {};
   std::array<Type *, Attribute::NumTypeAttrKinds> TypeAttrs = {};
 
   Optional<unsigned> kindToIntIndex(Attribute::AttrKind Kind) const;
   Optional<unsigned> kindToTypeIndex(Attribute::AttrKind Kind) const;
 
 public:
-  AttrBuilder() = default;
+  AttrBuilder(LLVMContext &Ctx) : Ctx(Ctx) {}
   AttrBuilder(const AttrBuilder &) = delete;
   AttrBuilder(AttrBuilder &&) = default;
 
-  AttrBuilder(const Attribute &A) {
+  AttrBuilder(LLVMContext &Ctx, const Attribute &A) : Ctx(Ctx) {
     addAttribute(A);
   }
 
-  AttrBuilder(AttributeList AS, unsigned Idx);
-  AttrBuilder(AttributeSet AS);
+  AttrBuilder(LLVMContext &Ctx, AttributeList AS, unsigned Idx);
+  AttrBuilder(LLVMContext &Ctx, AttributeSet AS);
 
   void clear();
 
   /// Add an attribute to the builder.
   AttrBuilder &addAttribute(Attribute::AttrKind Val) {
     assert((unsigned)Val < Attribute::EndAttrKinds &&
            "Attribute out of range!");
     assert(Attribute::isEnumAttrKind(Val) &&

llvm/lib/AsmParser/LLParser.cpp

 /// end of the module.
 bool LLParser::validateEndOfModule(bool UpgradeDebugInfo) {
   if (!M)
     return false;
   // Handle any function attribute group forward references.
   for (const auto &RAG : ForwardRefAttrGroups) {
     Value *V = RAG.first;
     const std::vector<unsigned> &Attrs = RAG.second;
-    AttrBuilder B;
+    AttrBuilder B(Context);
 
-    for (const auto &Attr : Attrs)
-      B.merge(NumberedAttrBuilders[Attr]);
+    for (const auto &Attr : Attrs) {
+      auto R = NumberedAttrBuilders.find(Attr);
+      if (R != NumberedAttrBuilders.end())
+        B.merge(R->second);
+    }
 
     if (Function *Fn = dyn_cast<Function>(V)) {
       AttributeList AS = Fn->getAttributes();
-      AttrBuilder FnAttrs(AS.getFnAttrs());
+      AttrBuilder FnAttrs(M->getContext(), AS.getFnAttrs());
       AS = AS.removeFnAttributes(Context);
 
       FnAttrs.merge(B);
 
       // If the alignment was parsed as an attribute, move to the alignment
       // field.
       if (FnAttrs.hasAlignmentAttr()) {
         Fn->setAlignment(FnAttrs.getAlignment());
         FnAttrs.removeAttribute(Attribute::Alignment);
       }
 
       AS = AS.addFnAttributes(Context, FnAttrs);
       Fn->setAttributes(AS);
     } else if (CallInst *CI = dyn_cast<CallInst>(V)) {
       AttributeList AS = CI->getAttributes();
-      AttrBuilder FnAttrs(AS.getFnAttrs());
+      AttrBuilder FnAttrs(M->getContext(), AS.getFnAttrs());
       AS = AS.removeFnAttributes(Context);
       FnAttrs.merge(B);
       AS = AS.addFnAttributes(Context, FnAttrs);
       CI->setAttributes(AS);
     } else if (InvokeInst *II = dyn_cast<InvokeInst>(V)) {
       AttributeList AS = II->getAttributes();
-      AttrBuilder FnAttrs(AS.getFnAttrs());
+      AttrBuilder FnAttrs(M->getContext(), AS.getFnAttrs());
       AS = AS.removeFnAttributes(Context);
       FnAttrs.merge(B);
       AS = AS.addFnAttributes(Context, FnAttrs);
       II->setAttributes(AS);
     } else if (CallBrInst *CBI = dyn_cast<CallBrInst>(V)) {
       AttributeList AS = CBI->getAttributes();
-      AttrBuilder FnAttrs(AS.getFnAttrs());
+      AttrBuilder FnAttrs(M->getContext(), AS.getFnAttrs());
       AS = AS.removeFnAttributes(Context);
       FnAttrs.merge(B);
       AS = AS.addFnAttributes(Context, FnAttrs);
       CBI->setAttributes(AS);
     } else if (auto *GV = dyn_cast<GlobalVariable>(V)) {
-      AttrBuilder Attrs(GV->getAttributes());
+      AttrBuilder Attrs(M->getContext(), GV->getAttributes());
       Attrs.merge(B);
       GV->setAttributes(AttributeSet::get(Context,Attrs));
     } else {
       llvm_unreachable("invalid object with forward attribute group reference");
     }
   }
 
   // If there are entries in ForwardRefBlockAddresses at this point, the
if (Lex.getKind() == lltok::kw_section) {
         return true;
       if (C)
         GV->setComdat(C);
       else
         return tokError("unknown global variable property!");
     }
   }
 
-  AttrBuilder Attrs;
+  AttrBuilder Attrs(M->getContext());
   LocTy BuiltinLoc;
   std::vector<unsigned> FwdRefAttrGrps;
   if (parseFnAttributeValuePairs(Attrs, FwdRefAttrGrps, false, BuiltinLoc))
     return true;
   if (Attrs.hasAttributes() || !FwdRefAttrGrps.empty()) {
     GV->setAttributes(AttributeSet::get(Context, Attrs));
     ForwardRefAttrGroups[GV] = FwdRefAttrGrps;
   }
bool LLParser::parseUnnamedAttrGrp() {
   if (Lex.getKind() != lltok::AttrGrpID)
     return tokError("expected attribute group id");
 
   unsigned VarID = Lex.getUIntVal();
   std::vector<unsigned> unused;
   LocTy BuiltinLoc;
   Lex.Lex();
 
   if (parseToken(lltok::equal, "expected '=' here") ||
-      parseToken(lltok::lbrace, "expected '{' here") ||
-      parseFnAttributeValuePairs(NumberedAttrBuilders[VarID], unused, true,
-                                 BuiltinLoc) ||
+      parseToken(lltok::lbrace, "expected '{' here"))
+    return true;
+
+  auto R = NumberedAttrBuilders.find(VarID);
+  if (R == NumberedAttrBuilders.end())
+    R = NumberedAttrBuilders.emplace(VarID, AttrBuilder(M->getContext())).first;
+
+  if (parseFnAttributeValuePairs(R->second, unused, true, BuiltinLoc) ||
       parseToken(lltok::rbrace, "expected end of attribute group"))
     return true;
 
-  if (!NumberedAttrBuilders[VarID].hasAttributes())
+  if (!R->second.hasAttributes())
     return error(AttrGrpLoc, "attribute group has no attributes");
 
   return false;
 }
 
 static Attribute::AttrKind tokenToAttribute(lltok::Kind Kind) {
   switch (Kind) {
 #define GET_ATTR_NAMES
if (Lex.getKind() == lltok::dotdotdot) {
         return tokError(Twine(Msg) + "musttail call in non-varargs function");
       Lex.Lex();  // Lex the '...', it is purely for readability.
       return parseToken(lltok::rparen, "expected ')' at end of argument list");
     }
 
     // parse the argument.
     LocTy ArgLoc;
     Type *ArgTy = nullptr;
-    AttrBuilder ArgAttrs;
     Value *V;
     if (parseType(ArgTy, ArgLoc))
       return true;
 
+    AttrBuilder ArgAttrs(M->getContext());
+
     if (ArgTy->isMetadataTy()) {
       if (parseMetadataAsValue(V, PFS))
         return true;
     } else {
       // Otherwise, handle normal operands.
       if (parseOptionalParamAttrs(ArgAttrs) || parseValue(ArgTy, V, PFS))
         return true;
     }
bool LLParser::parseArgumentList(SmallVectorImpl<ArgInfo> &ArgList,
   if (Lex.getKind() == lltok::rparen) {
     // empty
   } else if (Lex.getKind() == lltok::dotdotdot) {
     IsVarArg = true;
     Lex.Lex();
   } else {
     LocTy TypeLoc = Lex.getLoc();
     Type *ArgTy = nullptr;
-    AttrBuilder Attrs;
+    AttrBuilder Attrs(M->getContext());
     std::string Name;
 
     if (parseType(ArgTy) || parseOptionalParamAttrs(Attrs))
       return true;
 
     if (ArgTy->isVoidTy())
       return error(TypeLoc, "argument can not have void type");
 

 ///       OptGC OptionalPrefix OptionalPrologue OptPersonalityFn
 bool LLParser::parseFunctionHeader(Function *&Fn, bool IsDefine) {
   // parse the linkage.
   LocTy LinkageLoc = Lex.getLoc();
   unsigned Linkage;
   unsigned Visibility;
   unsigned DLLStorageClass;
   bool DSOLocal;
-  AttrBuilder RetAttrs;
+  AttrBuilder RetAttrs(M->getContext());
   unsigned CC;
   bool HasLinkage;
   Type *RetType = nullptr;
   LocTy RetTypeLoc = Lex.getLoc();
   if (parseOptionalLinkage(Linkage, HasLinkage, Visibility, DLLStorageClass,
                            DSOLocal) ||
       parseOptionalCallingConv(CC) || parseOptionalReturnAttrs(RetAttrs) ||
       parseType(RetType, RetTypeLoc, true /*void allowed*/))
bool LLParser::parseFunctionHeader(Function *&Fn, bool IsDefine) {
 
   Lex.Lex();
 
   if (Lex.getKind() != lltok::lparen)
     return tokError("expected '(' in function argument list");
 
   SmallVector<ArgInfo, 8> ArgList;
   bool IsVarArg;
-  AttrBuilder FuncAttrs;
+  AttrBuilder FuncAttrs(M->getContext());
   std::vector<unsigned> FwdRefAttrGrps;
   LocTy BuiltinLoc;
   std::string Section;
   std::string Partition;
   MaybeAlign Alignment;
   std::string GC;
   GlobalValue::UnnamedAddr UnnamedAddr = GlobalValue::UnnamedAddr::None;
   unsigned AddrSpace = 0;
bool LLParser::parseIndirectBr(Instruction *&Inst, PerFunctionState &PFS) {
   return false;
 }
 
 /// parseInvoke
 ///   ::= 'invoke' OptionalCallingConv OptionalAttrs Type Value ParamList
 ///       OptionalAttrs 'to' TypeAndValue 'unwind' TypeAndValue
 bool LLParser::parseInvoke(Instruction *&Inst, PerFunctionState &PFS) {
   LocTy CallLoc = Lex.getLoc();
-  AttrBuilder RetAttrs, FnAttrs;
+  AttrBuilder RetAttrs(M->getContext()), FnAttrs(M->getContext());
   std::vector<unsigned> FwdRefAttrGrps;
   LocTy NoBuiltinLoc;
   unsigned CC;
   unsigned InvokeAddrSpace;
   Type *RetType = nullptr;
   LocTy RetTypeLoc;
   ValID CalleeID;
   SmallVector<ParamInfo, 16> ArgList;

 }
 
 /// parseCallBr
 ///   ::= 'callbr' OptionalCallingConv OptionalAttrs Type Value ParamList
 ///       OptionalAttrs OptionalOperandBundles 'to' TypeAndValue
 ///       '[' LabelList ']'
 bool LLParser::parseCallBr(Instruction *&Inst, PerFunctionState &PFS) {
   LocTy CallLoc = Lex.getLoc();
-  AttrBuilder RetAttrs, FnAttrs;
+  AttrBuilder RetAttrs(M->getContext()), FnAttrs(M->getContext());
   std::vector<unsigned> FwdRefAttrGrps;
   LocTy NoBuiltinLoc;
   unsigned CC;
   Type *RetType = nullptr;
   LocTy RetTypeLoc;
   ValID CalleeID;
   SmallVector<ParamInfo, 16> ArgList;
   SmallVector<OperandBundleDef, 2> BundleList;

 ///   ::= 'tail' 'call' OptionalFastMathFlags OptionalCallingConv
 ///           OptionalAttrs Type Value ParameterList OptionalAttrs
 ///   ::= 'musttail' 'call' OptionalFastMathFlags OptionalCallingConv
 ///           OptionalAttrs Type Value ParameterList OptionalAttrs
 ///   ::= 'notail' 'call'  OptionalFastMathFlags OptionalCallingConv
 ///           OptionalAttrs Type Value ParameterList OptionalAttrs
 bool LLParser::parseCall(Instruction *&Inst, PerFunctionState &PFS,
                          CallInst::TailCallKind TCK) {
-  AttrBuilder RetAttrs, FnAttrs;
+  AttrBuilder RetAttrs(M->getContext()), FnAttrs(M->getContext());
   std::vector<unsigned> FwdRefAttrGrps;
   LocTy BuiltinLoc;
   unsigned CallAddrSpace;
   unsigned CC;
   Type *RetType = nullptr;
   LocTy RetTypeLoc;
   ValID CalleeID;
   SmallVector<ParamInfo, 16> ArgList;

llvm/lib/Bitcode/Reader/BitcodeReader.cpp

while (true) {
     default:  // Default behavior: ignore.
       break;
     case bitc::PARAMATTR_CODE_ENTRY_OLD: // ENTRY: [paramidx0, attr0, ...]
       // Deprecated, but still needed to read old bitcode files.
       if (Record.size() & 1)
         return error("Invalid record");
 
       for (unsigned i = 0, e = Record.size(); i != e; i += 2) {
-        AttrBuilder B;
+        AttrBuilder B(Context);
         decodeLLVMAttributesForBitcode(B, Record[i+1]);
         Attrs.push_back(AttributeList::get(Context, Record[i], B));
       }
 
       MAttributes.push_back(AttributeList::get(Context, Attrs));
       Attrs.clear();
       break;
     case bitc::PARAMATTR_CODE_ENTRY: // ENTRY: [attrgrp0, attrgrp1, ...]
default:  // Default behavior: ignore.
       break;
     case bitc::PARAMATTR_GRP_CODE_ENTRY: { // ENTRY: [grpid, idx, a0, a1, ...]
       if (Record.size() < 3)
         return error("Invalid record");
 
       uint64_t GrpID = Record[0];
       uint64_t Idx = Record[1]; // Index of the object this attribute refers to.
 
-      AttrBuilder B;
+      AttrBuilder B(Context);
       for (unsigned i = 2, e = Record.size(); i != e; ++i) {
         if (Record[i] == 0) {        // Enum attribute
           Attribute::AttrKind Kind;
           if (Error Err = parseAttrKind(Record[++i], &Kind))
             return Err;
 
           // Upgrade old-style byval attribute to one with a type, even if it's
           // nullptr. We will have to insert the real type when we associate

llvm/lib/CodeGen/Analysis.cpp

bool llvm::attributesPermitTailCall(const Function *F, const Instruction *I,
                                     const ReturnInst *Ret,
                                     const TargetLoweringBase &TLI,
                                     bool *AllowDifferingSizes) {
   // ADS may be null, so don't write to it directly.
   bool DummyADS;
   bool &ADS = AllowDifferingSizes ? *AllowDifferingSizes : DummyADS;
   ADS = true;
 
-  AttrBuilder CallerAttrs(F->getAttributes(), AttributeList::ReturnIndex);
-  AttrBuilder CalleeAttrs(cast<CallInst>(I)->getAttributes(),
+  AttrBuilder CallerAttrs(F->getContext(), F->getAttributes(), AttributeList::ReturnIndex);
+  AttrBuilder CalleeAttrs(F->getContext(), cast<CallInst>(I)->getAttributes(),
                           AttributeList::ReturnIndex);
 
   // Following attributes are completely benign as far as calling convention
   // goes, they shouldn't affect whether the call is a tail call.
   for (const auto &Attr : {Attribute::Alignment, Attribute::Dereferenceable,
                            Attribute::DereferenceableOrNull, Attribute::NoAlias,
                            Attribute::NonNull}) {
     CallerAttrs.removeAttribute(Attr);

llvm/lib/CodeGen/CommandFlags.cpp

#define HANDLE_BOOL_ATTR(CL, AttrName)                                         \
   } while (0)
 
 /// Set function attributes of function \p F based on CPU, Features, and command
 /// line flags.
 void codegen::setFunctionAttributes(StringRef CPU, StringRef Features,
                                     Function &F) {
   auto &Ctx = F.getContext();
   AttributeList Attrs = F.getAttributes();
-  AttrBuilder NewAttrs;
+  AttrBuilder NewAttrs(Ctx);
 
   if (!CPU.empty() && !F.hasFnAttribute("target-cpu"))
     NewAttrs.addAttribute("target-cpu", CPU);
   if (!Features.empty()) {
     // Append the command line features to any that are already on the function.
     StringRef OldFeatures =
         F.getFnAttribute("target-features").getValueAsString();
     if (OldFeatures.empty())

llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp

static bool isLibCallInTailPosition(MachineInstr &MI,
                                     MachineRegisterInfo &MRI) {
   MachineBasicBlock &MBB = *MI.getParent();
   const Function &F = MBB.getParent()->getFunction();
 
   // Conservatively require the attributes of the call to match those of
   // the return. Ignore NoAlias and NonNull because they don't affect the
   // call sequence.
   AttributeList CallerAttrs = F.getAttributes();
-  if (AttrBuilder(CallerAttrs, AttributeList::ReturnIndex)
+  if (AttrBuilder(F.getContext(), CallerAttrs, AttributeList::ReturnIndex)
           .removeAttribute(Attribute::NoAlias)
           .removeAttribute(Attribute::NonNull)
           .hasAttributes())
     return false;
 
   // It's not safe to eliminate the sign / zero extension of the return value.
   if (CallerAttrs.hasRetAttr(Attribute::ZExt) ||
       CallerAttrs.hasRetAttr(Attribute::SExt))

llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp

bool TargetLowering::isInTailCallPosition(SelectionDAG &DAG, SDNode *Node,
 
   // First, check if tail calls have been disabled in this function.
   if (F.getFnAttribute("disable-tail-calls").getValueAsBool())
     return false;
 
   // Conservatively require the attributes of the call to match those of
   // the return. Ignore following attributes because they don't affect the
   // call sequence.
-  AttrBuilder CallerAttrs(F.getAttributes(), AttributeList::ReturnIndex);
+  AttrBuilder CallerAttrs(F.getContext(), F.getAttributes(), AttributeList::ReturnIndex);
   for (const auto &Attr : {Attribute::Alignment, Attribute::Dereferenceable,
                            Attribute::DereferenceableOrNull, Attribute::NoAlias,
                            Attribute::NonNull})
     CallerAttrs.removeAttribute(Attr);
 
   if (CallerAttrs.hasAttributes())
     return false;
 

llvm/lib/IR/Attributes.cpp

 
 AttributeSet AttributeSet::get(LLVMContext &C, ArrayRef<Attribute> Attrs) {
   return AttributeSet(AttributeSetNode::get(C, Attrs));
 }
 
 AttributeSet AttributeSet::addAttribute(LLVMContext &C,
                                         Attribute::AttrKind Kind) const {
   if (hasAttribute(Kind)) return *this;
-  AttrBuilder B;
+  AttrBuilder B(C);
   B.addAttribute(Kind);
   return addAttributes(C, AttributeSet::get(C, B));
 }
 
 AttributeSet AttributeSet::addAttribute(LLVMContext &C, StringRef Kind,
                                         StringRef Value) const {
-  AttrBuilder B;
+  AttrBuilder B(C);
   B.addAttribute(Kind, Value);
   return addAttributes(C, AttributeSet::get(C, B));
 }
 
 AttributeSet AttributeSet::addAttributes(LLVMContext &C,
                                          const AttributeSet AS) const {
   if (!hasAttributes())
     return AS;
 
   if (!AS.hasAttributes())
     return *this;
 
-  AttrBuilder B(AS);
+  AttrBuilder B(C, AS);
   for (const auto &I : *this)
     B.addAttribute(I);
 
  return get(C, B);
 }
 
 AttributeSet AttributeSet::removeAttribute(LLVMContext &C,
                                              Attribute::AttrKind Kind) const {
   if (!hasAttribute(Kind)) return *this;
-  AttrBuilder B(*this);
+  AttrBuilder B(C, *this);
   B.removeAttribute(Kind);
   return get(C, B);
 }
 
 AttributeSet AttributeSet::removeAttribute(LLVMContext &C,
                                              StringRef Kind) const {
   if (!hasAttribute(Kind)) return *this;
-  AttrBuilder B(*this);
+  AttrBuilder B(C, *this);
   B.removeAttribute(Kind);
   return get(C, B);
 }
 
 AttributeSet AttributeSet::removeAttributes(LLVMContext &C,
                                             const AttributeMask &Attrs) const {
-  AttrBuilder B(*this);
+  AttrBuilder B(C, *this);
   // If there is nothing to remove, directly return the original set.
   if (!B.overlaps(Attrs))
     return *this;
 
   B.remove(Attrs);
   return get(C, B);
 }
 
else if (Attribute::isIntAttrKind(Kind))
       Attr = Attribute::get(C, Kind, B.getRawIntAttr(Kind));
     else
       Attr = Attribute::get(C, Kind);
     Attrs.push_back(Attr);
   }
 
   // Add target-dependent (string) attributes.
   for (const auto &TDA : B.td_attrs())
-    Attrs.emplace_back(Attribute::get(C, TDA.first, TDA.second));
+    Attrs.push_back(TDA);
 
   return getSorted(C, Attrs);
 }
 
 bool AttributeSetNode::hasAttribute(StringRef Kind) const {
   return StringAttrs.count(Kind);
 }
 
for (const auto &List : Attrs)
     MaxSize = std::max(MaxSize, List.getNumAttrSets());
 
   // If every list was empty, there is no point in merging the lists.
   if (MaxSize == 0)
     return {};
 
   SmallVector<AttributeSet, 8> NewAttrSets(MaxSize);
   for (unsigned I = 0; I < MaxSize; ++I) {
-    AttrBuilder CurBuilder;
+    AttrBuilder CurBuilder(C);
     for (const auto &List : Attrs)
-      CurBuilder.merge(List.getAttributes(I - 1));
+      CurBuilder.merge(AttrBuilder(C, List.getAttributes(I - 1)));
     NewAttrSets[I] = AttributeSet::get(C, CurBuilder);
   }
 
   return getImpl(C, NewAttrSets);
 }
 
 AttributeList
 AttributeList::addAttributeAtIndex(LLVMContext &C, unsigned Index,
                                    Attribute::AttrKind Kind) const {
   if (hasAttributeAtIndex(Index, Kind))
     return *this;
   AttributeSet Attrs = getAttributes(Index);
   // TODO: Insert at correct position and avoid sort.
   SmallVector<Attribute, 8> NewAttrs(Attrs.begin(), Attrs.end());
   NewAttrs.push_back(Attribute::get(C, Kind));
   return setAttributesAtIndex(C, Index, AttributeSet::get(C, NewAttrs));
 }
 
 AttributeList AttributeList::addAttributeAtIndex(LLVMContext &C, unsigned Index,
                                                  StringRef Kind,
                                                  StringRef Value) const {
-  AttrBuilder B;
+  AttrBuilder B(C);
   B.addAttribute(Kind, Value);
   return addAttributesAtIndex(C, Index, B);
 }
 
 AttributeList AttributeList::addAttributeAtIndex(LLVMContext &C, unsigned Index,
                                                  Attribute A) const {
-  AttrBuilder B;
+  AttrBuilder B(C);
   B.addAttribute(A);
   return addAttributesAtIndex(C, Index, B);
 }
 
 AttributeList AttributeList::setAttributesAtIndex(LLVMContext &C,
                                                   unsigned Index,
                                                   AttributeSet Attrs) const {
   Index = attrIdxToArrayIdx(Index);
#ifndef NDEBUG
   // FIXME it is not obvious how this should work for alignment. For now, say
   // we can't change a known alignment.
   const MaybeAlign OldAlign = getAttributes(Index).getAlignment();
   const MaybeAlign NewAlign = B.getAlignment();
   assert((!OldAlign || !NewAlign || OldAlign == NewAlign) &&
          "Attempt to change alignment!");
 #endif
 
-  AttrBuilder Merged(getAttributes(Index));
+  AttrBuilder Merged(C, getAttributes(Index));
   Merged.merge(B);
   return setAttributesAtIndex(C, Index, AttributeSet::get(C, Merged));
 }
 
 AttributeList AttributeList::addParamAttribute(LLVMContext &C,
                                                ArrayRef<unsigned> ArgNos,
                                                Attribute A) const {
   assert(llvm::is_sorted(ArgNos));
 
   SmallVector<AttributeSet, 4> AttrSets(this->begin(), this->end());
   unsigned MaxIndex = attrIdxToArrayIdx(ArgNos.back() + FirstArgIndex);
   if (MaxIndex >= AttrSets.size())
     AttrSets.resize(MaxIndex + 1);
 
   for (unsigned ArgNo : ArgNos) {
     unsigned Index = attrIdxToArrayIdx(ArgNo + FirstArgIndex);
-    AttrBuilder B(AttrSets[Index]);
+    AttrBuilder B(C, AttrSets[Index]);
     B.addAttribute(A);
     AttrSets[Index] = AttributeSet::get(C, B);
   }
 
   return getImpl(C, AttrSets);
 }
 
 AttributeList
if (WithoutIndex >= getNumAttrSets())
     return *this;
   SmallVector<AttributeSet, 4> AttrSets(this->begin(), this->end());
   AttrSets[WithoutIndex] = AttributeSet();
   return getImpl(C, AttrSets);
 }
 
 AttributeList AttributeList::addDereferenceableRetAttr(LLVMContext &C,
                                                        uint64_t Bytes) const {
-  AttrBuilder B;
+  AttrBuilder B(C);
   B.addDereferenceableAttr(Bytes);
   return addRetAttributes(C, B);
 }
 
 AttributeList AttributeList::addDereferenceableParamAttr(LLVMContext &C,
                                                          unsigned Index,
                                                          uint64_t Bytes) const {
-  AttrBuilder B;
+  AttrBuilder B(C);
   B.addDereferenceableAttr(Bytes);
   return addParamAttributes(C, Index, B);
 }
 
 AttributeList
 AttributeList::addDereferenceableOrNullParamAttr(LLVMContext &C, unsigned Index,
                                                  uint64_t Bytes) const {
-  AttrBuilder B;
+  AttrBuilder B(C);
   B.addDereferenceableOrNullAttr(Bytes);
   return addParamAttributes(C, Index, B);
 }
 
 AttributeList
 AttributeList::addAllocSizeParamAttr(LLVMContext &C, unsigned Index,
                                      unsigned ElemSizeArg,
                                      const Optional<unsigned> &NumElemsArg) {
-  AttrBuilder B;
+  AttrBuilder B(C);
   B.addAllocSizeAttr(ElemSizeArg, NumElemsArg);
   return addParamAttributes(C, Index, B);
 }
 
 //===----------------------------------------------------------------------===//
 // AttributeList Accessor Methods
 //===----------------------------------------------------------------------===//
 

 LLVM_DUMP_METHOD void AttributeList::dump() const { print(dbgs()); }
 #endif
 
 //===----------------------------------------------------------------------===//
 // AttrBuilder Method Implementations
 //===----------------------------------------------------------------------===//
 
 // FIXME: Remove this ctor, use AttributeSet.
-AttrBuilder::AttrBuilder(AttributeList AL, unsigned Index) {
+AttrBuilder::AttrBuilder(LLVMContext &Ctx, AttributeList AL, unsigned Index)
+    : Ctx(Ctx) {
   AttributeSet AS = AL.getAttributes(Index);
   for (const auto &A : AS)
     addAttribute(A);
 }
 
-AttrBuilder::AttrBuilder(AttributeSet AS) {
+AttrBuilder::AttrBuilder(LLVMContext &Ctx, AttributeSet AS) : Ctx(Ctx) {
   for (const auto &A : AS)
     addAttribute(A);
 }
 
 void AttrBuilder::clear() {
   Attrs.reset();
   TargetDepAttrs.clear();
   IntAttrs = {};

 
 Optional<unsigned>
 AttrBuilder::kindToTypeIndex(Attribute::AttrKind Kind) const {
   if (Attribute::isTypeAttrKind(Kind))
     return Kind - Attribute::FirstTypeAttr;
   return None;
 }
 
+struct StringAttributeComparator {
+  bool operator()(Attribute A0, Attribute A1) const {
+    return A0.getKindAsString() < A1.getKindAsString();
+  }
+  bool operator()(Attribute A0, StringRef Kind) const {
+    return A0.getKindAsString() < Kind;
+  }
+};
+
 AttrBuilder &AttrBuilder::addAttribute(Attribute Attr) {
   if (Attr.isStringAttribute()) {
-    addAttribute(Attr.getKindAsString(), Attr.getValueAsString());
+    auto It = lower_bound(TargetDepAttrs, Attr, StringAttributeComparator());
+    if (It != TargetDepAttrs.end() && It->hasAttribute(Attr.getKindAsString()))
+      std::swap(*It, Attr);
+    else
+      TargetDepAttrs.insert(It, Attr);
     return *this;
   }
 
   Attribute::AttrKind Kind = Attr.getKindAsEnum();
   Attrs[Kind] = true;
 
   if (Optional<unsigned> TypeIndex = kindToTypeIndex(Kind))
     TypeAttrs[*TypeIndex] = Attr.getValueAsType();
   else if (Optional<unsigned> IntIndex = kindToIntIndex(Kind))
     IntAttrs[*IntIndex] = Attr.getValueAsInt();
 
   return *this;
 }
 
 AttrBuilder &AttrBuilder::addAttribute(StringRef A, StringRef V) {
-  TargetDepAttrs[A] = V;
-  return *this;
+  return addAttribute(Attribute::get(Ctx, A, V));
 }
 
 AttrBuilder &AttrBuilder::removeAttributes(AttributeList AL, uint64_t Index) {
   remove(AttributeMask(AL.getAttributes(Index)));
   return *this;
 }
 
 AttrBuilder &AttrBuilder::removeAttribute(Attribute::AttrKind Val) {
   assert((unsigned)Val < Attribute::EndAttrKinds && "Attribute out of range!");
   Attrs[Val] = false;
 
   if (Optional<unsigned> TypeIndex = kindToTypeIndex(Val))
     TypeAttrs[*TypeIndex] = nullptr;
   else if (Optional<unsigned> IntIndex = kindToIntIndex(Val))
     IntAttrs[*IntIndex] = 0;
 
   return *this;
 }
 
 AttrBuilder &AttrBuilder::removeAttribute(StringRef A) {
-  TargetDepAttrs.erase(A);
+  auto It = lower_bound(TargetDepAttrs, A, StringAttributeComparator());
+  if (It != TargetDepAttrs.end() && It->hasAttribute(A))
+    TargetDepAttrs.erase(It);
   return *this;
 }
 
 uint64_t AttrBuilder::getRawIntAttr(Attribute::AttrKind Kind) const {
   Optional<unsigned> IntIndex = kindToIntIndex(Kind);
   assert(IntIndex && "Not an int attribute");
   return IntAttrs[*IntIndex];
 }
if (!IntAttrs[Index])
       IntAttrs[Index] = B.IntAttrs[Index];
 
   for (unsigned Index = 0; Index < Attribute::NumTypeAttrKinds; ++Index)
     if (!TypeAttrs[Index])
       TypeAttrs[Index] = B.TypeAttrs[Index];
 
   Attrs |= B.Attrs;
 
+  // TODO: could merge both lists in one loop
   for (const auto &I : B.td_attrs())
-    TargetDepAttrs[I.first] = I.second;
+    addAttribute(I);
 
   return *this;
 }
 
 AttrBuilder &AttrBuilder::remove(const AttributeMask &AM) {
-  // FIXME: What if both have an int/type attribute, but they don't match?!
   for (unsigned Index = 0; Index < Attribute::NumIntAttrKinds; ++Index)
     if (AM.contains((Attribute::AttrKind)Index))
       IntAttrs[Index] = 0;
 
   for (unsigned Index = 0; Index < Attribute::NumTypeAttrKinds; ++Index)
     if (AM.contains((Attribute::AttrKind)Index))
       TypeAttrs[Index] = nullptr;
 
   Attrs &= ~AM.attrs();
 
-  for (const auto &I : AM.td_attrs())
-    TargetDepAttrs.erase(I);
+  erase_if(TargetDepAttrs,
+           [&AM](Attribute A) { return AM.contains(A.getKindAsString()); });
 
   return *this;
 }
 
 bool AttrBuilder::overlaps(const AttributeMask &AM) const {
   // First check if any of the target independent attributes overlap.
   if ((Attrs & AM.attrs()).any())
     return true;
 
   // Then check if any target dependent ones do.
   for (const auto &I : td_attrs())
-    if (AM.contains(I.first))
+    if (AM.contains(I.getKindAsString()))
       return true;
   return false;
 }
 
 bool AttrBuilder::contains(StringRef A) const {
-  return TargetDepAttrs.find(A) != TargetDepAttrs.end();
+  auto It = lower_bound(TargetDepAttrs, A, StringAttributeComparator());
+  return It != TargetDepAttrs.end() && It->hasAttribute(A);
 }
 
 bool AttrBuilder::hasAttributes() const {
   return !Attrs.none() || !TargetDepAttrs.empty();
 }
 
 bool AttrBuilder::hasAttributes(AttributeList AL, uint64_t Index) const {
   AttributeSet AS = AL.getAttributes(Index);
bool AttrBuilder::hasAttributes(AttributeList AL, uint64_t Index) const {
   return false;
 }
 
 bool AttrBuilder::hasAlignmentAttr() const {
   return getRawIntAttr(Attribute::Alignment) != 0;
 }
 
 bool AttrBuilder::operator==(const AttrBuilder &B) const {
-  if (Attrs != B.Attrs)
-    return false;
-
-  for (const auto &TDA : TargetDepAttrs)
-    if (B.TargetDepAttrs.find(TDA.first) == B.TargetDepAttrs.end())
-      return false;
-
-  return IntAttrs == B.IntAttrs && TypeAttrs == B.TypeAttrs;
+  return Attrs == B.Attrs && IntAttrs == B.IntAttrs &&
+         TypeAttrs == B.TypeAttrs && TargetDepAttrs == B.TargetDepAttrs;
 }
 
 //===----------------------------------------------------------------------===//
 // AttributeFuncs Function Defintions
 //===----------------------------------------------------------------------===//
 
 /// Which attributes cannot be applied to a type.
 AttributeMask AttributeFuncs::typeIncompatible(Type *Ty) {

llvm/lib/IR/AutoUpgrade.cpp

std::string llvm::UpgradeDataLayoutString(StringRef DL, StringRef TT) {
 
   return (Groups[1] + AddrSpaces + Groups[3]).str();
 }
 
 void llvm::UpgradeAttributes(AttrBuilder &B) {
   StringRef FramePointer;
   if (B.contains("no-frame-pointer-elim")) {
     // The value can be "true" or "false".
-    for (const auto &I : B.td_attrs())
-      if (I.first == "no-frame-pointer-elim")
-        FramePointer = I.second == "true" ? "all" : "none";
+    for (const auto &A : B.td_attrs())
+      if (A.getKindAsString() == "no-frame-pointer-elim")
+        FramePointer = A.getValueAsString() == "true" ? "all" : "none";
     B.removeAttribute("no-frame-pointer-elim");
   }
   if (B.contains("no-frame-pointer-elim-non-leaf")) {
     // The value is ignored. "no-frame-pointer-elim"="true" takes priority.
     if (FramePointer != "all")
       FramePointer = "non-leaf";
     B.removeAttribute("no-frame-pointer-elim-non-leaf");
   }
   if (!FramePointer.empty())
     B.addAttribute("frame-pointer", FramePointer);
 
   if (B.contains("null-pointer-is-valid")) {
     // The value can be "true" or "false".
     bool NullPointerIsValid = false;
-    for (const auto &I : B.td_attrs())
-      if (I.first == "null-pointer-is-valid")
-        NullPointerIsValid = I.second == "true";
+    for (const auto &A : B.td_attrs())
+      if (A.getKindAsString() == "null-pointer-is-valid")
+        NullPointerIsValid = A.getValueAsString() == "true";
     B.removeAttribute("null-pointer-is-valid");
     if (NullPointerIsValid)
       B.addAttribute(Attribute::NullPointerIsValid);
   }
 }

llvm/lib/IR/Function.cpp

Function *Function::Create(FunctionType *Ty, LinkageTypes Linkage,
   return Create(Ty, Linkage, M.getDataLayout().getProgramAddressSpace(), N, &M);
 }
 
 Function *Function::createWithDefaultAttr(FunctionType *Ty,
                                           LinkageTypes Linkage,
                                           unsigned AddrSpace, const Twine &N,
                                           Module *M) {
   auto *F = new Function(Ty, Linkage, AddrSpace, N, M);
-  AttrBuilder B;
+  AttrBuilder B(F->getContext());
   if (M->getUwtable())
     B.addAttribute(Attribute::UWTable);
   switch (M->getFramePointer()) {
   case FramePointerKind::None:
     // 0 ("none") is the default.
     break;
   case FramePointerKind::NonLeaf:
     B.addAttribute("frame-pointer", "non-leaf");

llvm/lib/IR/Verifier.cpp

if (L == R)
     return true;
   PointerType *PL = dyn_cast<PointerType>(L);
   PointerType *PR = dyn_cast<PointerType>(R);
   if (!PL || !PR)
     return false;
   return PL->getAddressSpace() == PR->getAddressSpace();
 }
 
-static AttrBuilder getParameterABIAttributes(unsigned I, AttributeList Attrs) {
+static AttrBuilder getParameterABIAttributes(LLVMContext& C, unsigned I, AttributeList Attrs) {
   static const Attribute::AttrKind ABIAttrs[] = {
       Attribute::StructRet,  Attribute::ByVal,          Attribute::InAlloca,
       Attribute::InReg,      Attribute::StackAlignment, Attribute::SwiftSelf,
       Attribute::SwiftAsync, Attribute::SwiftError,     Attribute::Preallocated,
       Attribute::ByRef};
-  AttrBuilder Copy;
+  AttrBuilder Copy(C);
   for (auto AK : ABIAttrs) {
     Attribute Attr = Attrs.getParamAttrs(I).getAttribute(AK);
     if (Attr.isValid())
       Copy.addAttribute(Attr);
   }
 
   // `align` is ABI-affecting only in combination with `byval` or `byref`.
   if (Attrs.hasParamAttr(I, Attribute::Alignment) &&
void Verifier::verifyMustTailCall(CallInst &CI) {
   if (CI.getCallingConv() == CallingConv::SwiftTail ||
       CI.getCallingConv() == CallingConv::Tail) {
     StringRef CCName =
         CI.getCallingConv() == CallingConv::Tail ? "tailcc" : "swifttailcc";
 
     // - Only sret, byval, swiftself, and swiftasync ABI-impacting attributes
     //   are allowed in swifttailcc call
     for (unsigned I = 0, E = CallerTy->getNumParams(); I != E; ++I) {
-      AttrBuilder ABIAttrs = getParameterABIAttributes(I, CallerAttrs);
+      AttrBuilder ABIAttrs = getParameterABIAttributes(F->getContext(), I, CallerAttrs);
       SmallString<32> Context{CCName, StringRef(" musttail caller")};
       verifyTailCCMustTailAttrs(ABIAttrs, Context);
     }
     for (unsigned I = 0, E = CalleeTy->getNumParams(); I != E; ++I) {
-      AttrBuilder ABIAttrs = getParameterABIAttributes(I, CalleeAttrs);
+      AttrBuilder ABIAttrs = getParameterABIAttributes(F->getContext(), I, CalleeAttrs);
       SmallString<32> Context{CCName, StringRef(" musttail callee")};
       verifyTailCCMustTailAttrs(ABIAttrs, Context);
     }
     // - Varargs functions are not allowed
     Assert(!CallerTy->isVarArg(), Twine("cannot guarantee ") + CCName +
                                       " tail call for varargs function");
     return;
   }
 
for (unsigned I = 0, E = CallerTy->getNumParams(); I != E; ++I) {
           isTypeCongruent(CallerTy->getParamType(I), CalleeTy->getParamType(I)),
           "cannot guarantee tail call due to mismatched parameter types", &CI);
     }
   }
 
   // - All ABI-impacting function attributes, such as sret, byval, inreg,
   //   returned, preallocated, and inalloca, must match.
   for (unsigned I = 0, E = CallerTy->getNumParams(); I != E; ++I) {
-    AttrBuilder CallerABIAttrs = getParameterABIAttributes(I, CallerAttrs);
-    AttrBuilder CalleeABIAttrs = getParameterABIAttributes(I, CalleeAttrs);
+    AttrBuilder CallerABIAttrs = getParameterABIAttributes(F->getContext(), I, CallerAttrs);
+    AttrBuilder CalleeABIAttrs = getParameterABIAttributes(F->getContext(), I, CalleeAttrs);
     Assert(CallerABIAttrs == CalleeABIAttrs,
            "cannot guarantee tail call due to mismatched ABI impacting "
            "function attributes",
            &CI, CI.getOperand(I));
   }
 }
 
 void Verifier::visitCallInst(CallInst &CI) {

llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp

 }
 
 static Function *getEmscriptenFunction(FunctionType *Ty, const Twine &Name,
                                        Module *M) {
   Function* F = Function::Create(Ty, GlobalValue::ExternalLinkage, Name, M);
   // Tell the linker that this function is expected to be imported from the
   // 'env' module.
   if (!F->hasFnAttribute("wasm-import-module")) {
-    llvm::AttrBuilder B;
+    llvm::AttrBuilder B(M->getContext());
     B.addAttribute("wasm-import-module", "env");
     F->addFnAttrs(B);
   }
   if (!F->hasFnAttribute("wasm-import-name")) {
-    llvm::AttrBuilder B;
+    llvm::AttrBuilder B(M->getContext());
     B.addAttribute("wasm-import-name", F->getName());
     F->addFnAttrs(B);
   }
   return F;
 }
 
 // Returns an integer type for the target architecture's address space.
 // i32 for wasm32 and i64 for wasm64.
Value *WebAssemblyLowerEmscriptenEHSjLj::wrapInvoke(CallBase *CI) {
   const AttributeList &InvokeAL = CI->getAttributes();
 
   // No attributes for the callee pointer.
   ArgAttributes.push_back(AttributeSet());
   // Copy the argument attributes from the original
   for (unsigned I = 0, E = CI->arg_size(); I < E; ++I)
     ArgAttributes.push_back(InvokeAL.getParamAttrs(I));
 
-  AttrBuilder FnAttrs(InvokeAL.getFnAttrs());
+  AttrBuilder FnAttrs(CI->getContext(), InvokeAL.getFnAttrs());
   if (FnAttrs.contains(Attribute::AllocSize)) {
     // The allocsize attribute (if any) referes to parameters by index and needs
     // to be adjusted.
     unsigned SizeArg;
     Optional<unsigned> NEltArg;
     std::tie(SizeArg, NEltArg) = FnAttrs.getAllocSizeArgs();
     SizeArg += 1;
     if (NEltArg.hasValue())

llvm/lib/Transforms/Coroutines/CoroSplit.cpp

Value *CoroCloner::deriveNewFramePointer() {
   }
   }
   llvm_unreachable("bad ABI");
 }
 
 static void addFramePointerAttrs(AttributeList &Attrs, LLVMContext &Context,
                                  unsigned ParamIndex,
                                  uint64_t Size, Align Alignment) {
-  AttrBuilder ParamAttrs;
+  AttrBuilder ParamAttrs(Context);
   ParamAttrs.addAttribute(Attribute::NonNull);
   ParamAttrs.addAttribute(Attribute::NoAlias);
   ParamAttrs.addAlignmentAttr(Alignment);
   ParamAttrs.addDereferenceableAttr(Size);
   Attrs = Attrs.addParamAttributes(Context, ParamIndex, ParamAttrs);
 }
 
 static void addAsyncContextAttrs(AttributeList &Attrs, LLVMContext &Context,
                                  unsigned ParamIndex) {
-  AttrBuilder ParamAttrs;
+  AttrBuilder ParamAttrs(Context);
   ParamAttrs.addAttribute(Attribute::SwiftAsync);
   Attrs = Attrs.addParamAttributes(Context, ParamIndex, ParamAttrs);
 }
 
 static void addSwiftSelfAttrs(AttributeList &Attrs, LLVMContext &Context,
                               unsigned ParamIndex) {
-  AttrBuilder ParamAttrs;
+  AttrBuilder ParamAttrs(Context);
   ParamAttrs.addAttribute(Attribute::SwiftSelf);
   Attrs = Attrs.addParamAttributes(Context, ParamIndex, ParamAttrs);
 }
 
 /// Clone the body of the original function into a resume function of
 /// some sort.
 void CoroCloner::create() {
   // Create the new function if we don't already have one.
void CoroCloner::create() {
   // Replace the attributes of the new function:
   auto OrigAttrs = NewF->getAttributes();
   auto NewAttrs = AttributeList();
 
   switch (Shape.ABI) {
   case coro::ABI::Switch:
     // Bootstrap attributes by copying function attributes from the
     // original function.  This should include optimization settings and so on.
-    NewAttrs = NewAttrs.addFnAttributes(Context, OrigAttrs.getFnAttrs());
+    NewAttrs = NewAttrs.addFnAttributes(Context, AttrBuilder(Context, OrigAttrs.getFnAttrs()));
 
     addFramePointerAttrs(NewAttrs, Context, 0,
                          Shape.FrameSize, Shape.FrameAlign);
     break;
   case coro::ABI::Async: {
     auto *ActiveAsyncSuspend = cast<CoroSuspendAsyncInst>(ActiveSuspend);
     if (OrigF.hasParamAttribute(Shape.AsyncLowering.ContextArgNo,
                                 Attribute::SwiftAsync)) {
       uint32_t ArgAttributeIndices =
           ActiveAsyncSuspend->getStorageArgumentIndex();
       auto ContextArgIndex = ArgAttributeIndices & 0xff;
       addAsyncContextAttrs(NewAttrs, Context, ContextArgIndex);
 
       // `swiftasync` must preceed `swiftself` so 0 is not a valid index for
       // `swiftself`.
       auto SwiftSelfIndex = ArgAttributeIndices >> 8;
       if (SwiftSelfIndex)
         addSwiftSelfAttrs(NewAttrs, Context, SwiftSelfIndex);
     }
 
     // Transfer the original function's attributes.
     auto FnAttrs = OrigF.getAttributes().getFnAttrs();
-    NewAttrs = NewAttrs.addFnAttributes(Context, FnAttrs);
+    NewAttrs = NewAttrs.addFnAttributes(Context, AttrBuilder(Context, FnAttrs));
     break;
   }
   case coro::ABI::Retcon:
   case coro::ABI::RetconOnce:
     // If we have a continuation prototype, just use its attributes,
     // full-stop.
     NewAttrs = Shape.RetconLowering.ResumePrototype->getAttributes();
 

llvm/lib/Transforms/IPO/DeadArgumentElimination.cpp

if (RetTy->isVoidTy() || HasLiveReturnedArg) {
     else if (RetTypes.empty())
       // No return types? Make it void, but only if we didn't use to return {}.
       NRetTy = Type::getVoidTy(F->getContext());
   }
 
   assert(NRetTy && "No new return type found?");
 
   // The existing function return attributes.
-  AttrBuilder RAttrs(PAL.getRetAttrs());
+  AttrBuilder RAttrs(F->getContext(), PAL.getRetAttrs());
 
   // Remove any incompatible attributes, but only if we removed all return
   // values. Otherwise, ensure that we don't have any conflicting attributes
   // here. Currently, this should not be possible, but special handling might be
   // required when new return value attributes are added.
   if (NRetTy->isVoidTy())
     RAttrs.remove(AttributeFuncs::typeIncompatible(NRetTy));
   else
bool DeadArgumentEliminationPass::RemoveDeadStuffFromFunction(Function *F) {
   while (!F->use_empty()) {
     CallBase &CB = cast<CallBase>(*F->user_back());
 
     ArgAttrVec.clear();
     const AttributeList &CallPAL = CB.getAttributes();
 
     // Adjust the call return attributes in case the function was changed to
     // return void.
-    AttrBuilder RAttrs(CallPAL.getRetAttrs());
+    AttrBuilder RAttrs(F->getContext(), CallPAL.getRetAttrs());
     RAttrs.remove(AttributeFuncs::typeIncompatible(NRetTy));
     AttributeSet RetAttrs = AttributeSet::get(F->getContext(), RAttrs);
 
     // Declare these outside of the loops, so we can reuse them for the second
     // loop, which loops the varargs.
     auto I = CB.arg_begin();
     unsigned Pi = 0;
     // Loop over those operands, corresponding to the normal arguments to the
     // original function, and add those that are still alive.
     for (unsigned E = FTy->getNumParams(); Pi != E; ++I, ++Pi)
       if (ArgAlive[Pi]) {
         Args.push_back(*I);
         // Get original parameter attributes, but skip return attributes.
         AttributeSet Attrs = CallPAL.getParamAttrs(Pi);
         if (NRetTy != RetTy && Attrs.hasAttribute(Attribute::Returned)) {
           // If the return type has changed, then get rid of 'returned' on the
           // call site. The alternative is to make all 'returned' attributes on
           // call sites keep the return value alive just like 'returned'
           // attributes on function declaration but it's less clearly a win and
           // this is not an expected case anyway
           ArgAttrVec.push_back(AttributeSet::get(
               F->getContext(),
-              AttrBuilder(Attrs).removeAttribute(Attribute::Returned)));
+              AttrBuilder(F->getContext(), Attrs).removeAttribute(Attribute::Returned)));
         } else {
           // Otherwise, use the original attributes.
           ArgAttrVec.push_back(Attrs);
         }
       }
 
     // Push any varargs arguments on the list. Don't forget their attributes.
     for (auto E = CB.arg_end(); I != E; ++I, ++Pi) {

llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp

if (!CastInst::isBitOrNoopPointerCastable(NewRetTy, OldRetTy, DL)) {
 
       if (!Caller->use_empty() &&
           // void -> non-void is handled specially
           !NewRetTy->isVoidTy())
         return false;   // Cannot transform this return value.
     }
 
     if (!CallerPAL.isEmpty() && !Caller->use_empty()) {
-      AttrBuilder RAttrs(CallerPAL, AttributeList::ReturnIndex);
+      AttrBuilder RAttrs(FT->getContext(), CallerPAL, AttributeList::ReturnIndex);
       if (RAttrs.overlaps(AttributeFuncs::typeIncompatible(NewRetTy)))
         return false;   // Attribute not compatible with transformed value.
     }
 
     // If the callbase is an invoke/callbr instruction, and the return value is
     // used by a PHI node in a successor, we cannot change the return type of
     // the call because there is no place to put the cast instruction (without
     // breaking the critical edge).  Bail out in this case.
bool InstCombinerImpl::transformConstExprCastCall(CallBase &Call) {
   auto AI = Call.arg_begin();
   for (unsigned i = 0, e = NumCommonArgs; i != e; ++i, ++AI) {
     Type *ParamTy = FT->getParamType(i);
     Type *ActTy = (*AI)->getType();
 
     if (!CastInst::isBitOrNoopPointerCastable(ActTy, ParamTy, DL))
       return false;   // Cannot transform this parameter value.
 
-    if (AttrBuilder(CallerPAL.getParamAttrs(i))
+    if (AttrBuilder(FT->getContext(), CallerPAL.getParamAttrs(i))
             .overlaps(AttributeFuncs::typeIncompatible(ParamTy)))
       return false;   // Attribute not compatible with transformed value.
 
     if (Call.isInAllocaArgument(i))
       return false;   // Cannot transform to and from inalloca.
 
     if (CallerPAL.hasParamAttr(i, Attribute::SwiftError))
       return false;
bool InstCombinerImpl::transformConstExprCastCall(CallBase &Call) {
   // Okay, we decided that this is a safe thing to do: go ahead and start
   // inserting cast instructions as necessary.
   SmallVector<Value *, 8> Args;
   SmallVector<AttributeSet, 8> ArgAttrs;
   Args.reserve(NumActualArgs);
   ArgAttrs.reserve(NumActualArgs);
 
   // Get any return attributes.
-  AttrBuilder RAttrs(CallerPAL, AttributeList::ReturnIndex);
+  AttrBuilder RAttrs(FT->getContext(), CallerPAL, AttributeList::ReturnIndex);
 
   // If the return value is not being used, the type may not be compatible
   // with the existing attributes.  Wipe out any problematic attributes.
   RAttrs.remove(AttributeFuncs::typeIncompatible(NewRetTy));
 
   LLVMContext &Ctx = Call.getContext();
   AI = Call.arg_begin();
   for (unsigned i = 0; i != NumCommonArgs; ++i, ++AI) {
     Type *ParamTy = FT->getParamType(i);
 
     Value *NewArg = *AI;
     if ((*AI)->getType() != ParamTy)
       NewArg = Builder.CreateBitOrPointerCast(*AI, ParamTy);
     Args.push_back(NewArg);
 
     // Add any parameter attributes.
     if (CallerPAL.hasParamAttr(i, Attribute::ByVal)) {
-      AttrBuilder AB(CallerPAL.getParamAttrs(i));
+      AttrBuilder AB(FT->getContext(), CallerPAL.getParamAttrs(i));
       AB.addByValAttr(NewArg->getType()->getPointerElementType());
       ArgAttrs.push_back(AttributeSet::get(Ctx, AB));
     } else
       ArgAttrs.push_back(CallerPAL.getParamAttrs(i));
   }
 
   // If the function takes more arguments than the call was taking, add them
   // now.

llvm/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp

 // Create new attribute set containing only attributes which can be transferred
 // from original call to the safepoint.
 static AttributeList legalizeCallAttributes(LLVMContext &Ctx,
                                             AttributeList AL) {
   if (AL.isEmpty())
     return AL;
 
   // Remove the readonly, readnone, and statepoint function attributes.
-  AttrBuilder FnAttrs = AL.getFnAttrs();
+  AttrBuilder FnAttrs(Ctx, AL.getFnAttrs());
   for (auto Attr : FnAttrsToStrip)
     FnAttrs.removeAttribute(Attr);
 
   for (Attribute A : AL.getFnAttrs()) {
     if (isStatepointDirectiveAttr(A))
       FnAttrs.removeAttribute(A);
   }
 

llvm/lib/Transforms/Utils/CallPromotionUtils.cpp

for (unsigned ArgNo = 0; ArgNo < CalleeParamNum; ++ArgNo) {
     auto *Arg = CB.getArgOperand(ArgNo);
     Type *FormalTy = CalleeType->getParamType(ArgNo);
     Type *ActualTy = Arg->getType();
     if (FormalTy != ActualTy) {
       auto *Cast = CastInst::CreateBitOrPointerCast(Arg, FormalTy, "", &CB);
       CB.setArgOperand(ArgNo, Cast);
 
       // Remove any incompatible attributes for the argument.
-      AttrBuilder ArgAttrs(CallerPAL.getParamAttrs(ArgNo));
+      AttrBuilder ArgAttrs(Ctx, CallerPAL.getParamAttrs(ArgNo));
       ArgAttrs.remove(AttributeFuncs::typeIncompatible(FormalTy));
 
       // We may have a different byval/inalloca type.
       if (ArgAttrs.getByValType())
         ArgAttrs.addByValAttr(Callee->getParamByValType(ArgNo));
       if (ArgAttrs.getInAllocaType())
         ArgAttrs.addInAllocaAttr(Callee->getParamInAllocaType(ArgNo));
 
       NewArgAttrs.push_back(AttributeSet::get(Ctx, ArgAttrs));
       AttributeChanged = true;
     } else
       NewArgAttrs.push_back(CallerPAL.getParamAttrs(ArgNo));
   }
 
   // If the return type of the call site doesn't match that of the callee, cast
   // the returned value to the appropriate type.
   // Remove any incompatible return value attribute.
-  AttrBuilder RAttrs(CallerPAL, AttributeList::ReturnIndex);
+  AttrBuilder RAttrs(Ctx, CallerPAL, AttributeList::ReturnIndex);
   if (!CallSiteRetTy->isVoidTy() && CallSiteRetTy != CalleeRetTy) {
     createRetBitCast(CB, CallSiteRetTy, RetBitCast);
     RAttrs.remove(AttributeFuncs::typeIncompatible(CalleeRetTy));
     AttributeChanged = true;
   }
 
   // Set the new callsite attribute.
   if (AttributeChanged)

llvm/lib/Transforms/Utils/InlineFunction.cpp

static bool MayContainThrowingOrExitingCall(Instruction *Begin,
   assert(Begin->getParent() == End->getParent() &&
          "Expected to be in same basic block!");
   return !llvm::isGuaranteedToTransferExecutionToSuccessor(
       Begin->getIterator(), End->getIterator(), InlinerAttributeWindow + 1);
 }
 
 static AttrBuilder IdentifyValidAttributes(CallBase &CB) {
 
-  AttrBuilder AB(CB.getAttributes(), AttributeList::ReturnIndex);
+  AttrBuilder AB(CB.getContext(), CB.getAttributes(), AttributeList::ReturnIndex);
   if (AB.empty())
     return AB;
-  AttrBuilder Valid;
+  AttrBuilder Valid(CB.getContext());
   // Only allow these white listed attributes to be propagated back to the
   // callee. This is because other attributes may only be valid on the call
   // itself, i.e. attributes such as signext and zeroext.
   if (auto DerefBytes = AB.getDereferenceableBytes())
     Valid.addDereferenceableAttr(DerefBytes);
   if (auto DerefOrNullBytes = AB.getDereferenceableOrNullBytes())
     Valid.addDereferenceableOrNullAttr(DerefOrNullBytes);
   if (AB.contains(Attribute::NoAlias))

llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp

if (SrcLen) {
     return nullptr;
   }
 
   if (SrcLen == 0) {
     // strncpy(x, "", y) -> memset(x, '\0', y)
     Align MemSetAlign =
         CI->getAttributes().getParamAttrs(0).getAlignment().valueOrOne();
     CallInst *NewCI = B.CreateMemSet(Dst, B.getInt8('\0'), Size, MemSetAlign);
-    AttrBuilder ArgAttrs(CI->getAttributes().getParamAttrs(0));
+    AttrBuilder ArgAttrs(CI->getContext(), CI->getAttributes().getParamAttrs(0));
     NewCI->setAttributes(NewCI->getAttributes().addParamAttributes(
         CI->getContext(), 0, ArgAttrs));
     copyFlags(*CI, NewCI);
     return Dst;
   }
 
   // strncpy(a, "a", 4) - > memcpy(a, "a\0\0\0", 4)
   if (Len > SrcLen + 1) {

llvm/tools/bugpoint/CrashDebugger.cpp

 bool ReduceCrashingFunctionAttributes::TestFuncAttrs(
     std::vector<Attribute> &Attrs) {
   // Clone the program to try hacking it apart...
   std::unique_ptr<Module> M = CloneModule(BD.getProgram());
   Function *F = M->getFunction(FnName);
 
   // Build up an AttributeList from the attributes we've been given by the
   // reducer.
-  AttrBuilder AB;
+  AttrBuilder AB(M->getContext());
   for (auto A : Attrs)
     AB.addAttribute(A);
   AttributeList NewAttrs;
   NewAttrs = NewAttrs.addFnAttributes(BD.getContext(), AB);
 
   // Set this new list of attributes on the function.
   F->setAttributes(NewAttrs);
 

llvm/tools/llvm-reduce/deltas/ReduceAttributes.cpp

struct AttributeCounter : public InstVisitor<AttributeCounter> {
   }
 };
 
 } // namespace
 
 AttributeSet
 convertAttributeRefToAttributeSet(LLVMContext &C,
                                   ArrayRef<const Attribute *> Attributes) {
-  AttrBuilder B;
+  AttrBuilder B(C);
   for (const Attribute *A : Attributes)
     B.addAttribute(*A);
   return AttributeSet::get(C, B);
 }
 
 AttributeList convertAttributeRefVecToAttributeList(
     LLVMContext &C, ArrayRef<AttrPtrIdxVecVecTy> AttributeSets) {
   std::vector<std::pair<unsigned, AttributeSet>> SetVec;

llvm/unittests/ExecutionEngine/Orc/IndirectionUtilsTest.cpp

TEST(IndirectionUtilsTest, MakeStub) {
   LLVMContext Context;
   ModuleBuilder MB(Context, "x86_64-apple-macosx10.10", "");
   StructType *ArgTy = getDummyStructTy(Context);
   Type *ArgPtrTy = PointerType::getUnqual(ArgTy);
   FunctionType *FTy = FunctionType::get(
       Type::getVoidTy(Context), {ArgPtrTy, ArgPtrTy}, false);
   Function *F = MB.createFunctionDecl(FTy, "");
   AttributeSet FnAttrs = AttributeSet::get(
-      Context, AttrBuilder().addAttribute(Attribute::NoUnwind));
+      Context, AttrBuilder(Context).addAttribute(Attribute::NoUnwind));
   AttributeSet RetAttrs; // None
   AttributeSet ArgAttrs[2] = {
-      AttributeSet::get(Context, AttrBuilder().addStructRetAttr(ArgTy)),
-      AttributeSet::get(Context, AttrBuilder().addByValAttr(ArgTy)),
+      AttributeSet::get(Context, AttrBuilder(Context).addStructRetAttr(ArgTy)),
+      AttributeSet::get(Context, AttrBuilder(Context).addByValAttr(ArgTy)),
   };
   F->setAttributes(AttributeList::get(Context, FnAttrs, RetAttrs, ArgAttrs));
 
   auto ImplPtr = orc::createImplPointer(*F->getType(), *MB.getModule(), "", nullptr);
   orc::makeStub(*F, *ImplPtr);
 
   auto II = F->getEntryBlock().begin();
   EXPECT_TRUE(isa<LoadInst>(*II)) << "First instruction of stub should be a load.";

llvm/unittests/IR/AttributesTest.cpp

TEST(Attributes, Ordering) {
   AttributeList SetB =
       SetA.removeParamAttributes(C, 0, ASs[1].getParamAttrs(0));
   EXPECT_NE(SetA, SetB);
 }
 
 TEST(Attributes, AddAttributes) {
   LLVMContext C;
   AttributeList AL;
-  AttrBuilder B;
+  AttrBuilder B(C);
   B.addAttribute(Attribute::NoReturn);
-  AL = AL.addFnAttributes(C, AttributeSet::get(C, B));
+  AL = AL.addFnAttributes(C, AttrBuilder(C, AttributeSet::get(C, B)));
   EXPECT_TRUE(AL.hasFnAttr(Attribute::NoReturn));
   B.clear();
   B.addAttribute(Attribute::SExt);
   AL = AL.addRetAttributes(C, B);
   EXPECT_TRUE(AL.hasRetAttr(Attribute::SExt));
   EXPECT_TRUE(AL.hasFnAttr(Attribute::NoReturn));
 }
 
 TEST(Attributes, RemoveAlign) {
   LLVMContext C;
 
   Attribute AlignAttr = Attribute::getWithAlignment(C, Align(8));
   Attribute StackAlignAttr = Attribute::getWithStackAlignment(C, Align(32));
-  AttrBuilder B_align_readonly;
+  AttrBuilder B_align_readonly(C);
   B_align_readonly.addAttribute(AlignAttr);
   B_align_readonly.addAttribute(Attribute::ReadOnly);
   AttributeMask B_align;
   B_align.addAttribute(AlignAttr);
-  AttrBuilder B_stackalign_optnone;
+  AttrBuilder B_stackalign_optnone(C);
   B_stackalign_optnone.addAttribute(StackAlignAttr);
   B_stackalign_optnone.addAttribute(Attribute::OptimizeNone);
   AttributeMask B_stackalign;
   B_stackalign.addAttribute(StackAlignAttr);
 
   AttributeSet AS = AttributeSet::get(C, B_align_readonly);
   EXPECT_TRUE(AS.getAlignment() == 8);
   EXPECT_TRUE(AS.hasAttribute(Attribute::ReadOnly));

 TEST(Attributes, AddMatchingAlignAttr) {
   LLVMContext C;
   AttributeList AL;
   AL = AL.addParamAttribute(C, 0, Attribute::getWithAlignment(C, Align(8)));
   AL = AL.addParamAttribute(C, 1, Attribute::getWithAlignment(C, Align(32)));
   EXPECT_EQ(Align(8), AL.getParamAlignment(0));
   EXPECT_EQ(Align(32), AL.getParamAlignment(1));
 
-  AttrBuilder B;
+  AttrBuilder B(C);
   B.addAttribute(Attribute::NonNull);
   B.addAlignmentAttr(8);
   AL = AL.addParamAttributes(C, 0, B);
   EXPECT_EQ(Align(8), AL.getParamAlignment(0));
   EXPECT_EQ(Align(32), AL.getParamAlignment(1));
   EXPECT_TRUE(AL.hasParamAttr(0, Attribute::NonNull));
 }
 

llvm/unittests/IR/InstructionsTest.cpp

for (CallInst::TailCallKind TCK : Kinds) {
     Call->setTailCallKind(TCK);
     std::unique_ptr<CallInst> Clone(cast<CallInst>(Call->clone()));
     EXPECT_EQ(Call->getTailCallKind(), Clone->getTailCallKind());
   }
   Call->setTailCallKind(CallInst::TCK_None);
 
   // Test cloning an attribute.
   {
-    AttrBuilder AB;
+    AttrBuilder AB(C);
     AB.addAttribute(Attribute::ReadOnly);
     Call->setAttributes(
         AttributeList::get(C, AttributeList::FunctionIndex, AB));
     std::unique_ptr<CallInst> Clone(cast<CallInst>(Call->clone()));
     EXPECT_TRUE(Clone->onlyReadsMemory());
   }
 }
 
 TEST(InstructionsTest, AlterCallBundles) {
   LLVMContext C;
   Type *Int32Ty = Type::getInt32Ty(C);
   FunctionType *FnTy = FunctionType::get(Int32Ty, Int32Ty, /*isVarArg=*/false);
   Value *Callee = Constant::getNullValue(FnTy->getPointerTo());
   Value *Args[] = {ConstantInt::get(Int32Ty, 42)};
   OperandBundleDef OldBundle("before", UndefValue::get(Int32Ty));
   std::unique_ptr<CallInst> Call(
       CallInst::Create(FnTy, Callee, Args, OldBundle, "result"));
   Call->setTailCallKind(CallInst::TailCallKind::TCK_NoTail);
-  AttrBuilder AB;
+  AttrBuilder AB(C);
   AB.addAttribute(Attribute::Cold);
   Call->setAttributes(AttributeList::get(C, AttributeList::FunctionIndex, AB));
   Call->setDebugLoc(DebugLoc(MDNode::get(C, None)));
 
   OperandBundleDef NewBundle("after", ConstantInt::get(Int32Ty, 7));
   std::unique_ptr<CallInst> Clone(CallInst::Create(Call.get(), NewBundle));
   EXPECT_EQ(Call->arg_size(), Clone->arg_size());
   EXPECT_EQ(Call->getArgOperand(0), Clone->getArgOperand(0));
TEST(InstructionsTest, AlterInvokeBundles) {
   Value *Callee = Constant::getNullValue(FnTy->getPointerTo());
   Value *Args[] = {ConstantInt::get(Int32Ty, 42)};
   std::unique_ptr<BasicBlock> NormalDest(BasicBlock::Create(C));
   std::unique_ptr<BasicBlock> UnwindDest(BasicBlock::Create(C));
   OperandBundleDef OldBundle("before", UndefValue::get(Int32Ty));
   std::unique_ptr<InvokeInst> Invoke(
       InvokeInst::Create(FnTy, Callee, NormalDest.get(), UnwindDest.get(), Args,
                          OldBundle, "result"));
-  AttrBuilder AB;
+  AttrBuilder AB(C);
   AB.addAttribute(Attribute::Cold);
   Invoke->setAttributes(
       AttributeList::get(C, AttributeList::FunctionIndex, AB));
   Invoke->setDebugLoc(DebugLoc(MDNode::get(C, None)));
 
   OperandBundleDef NewBundle("after", ConstantInt::get(Int32Ty, 7));
   std::unique_ptr<InvokeInst> Clone(
       InvokeInst::Create(Invoke.get(), NewBundle));

mlir/lib/Target/LLVMIR/ModuleTranslation.cpp

if (auto attr = func.getArgAttrOfType<IntegerAttr>(
             argIdx, LLVMDialect::getAlignAttrName())) {
       // NB: Attribute already verified to be int, so check if we can indeed
       // attach the attribute to this argument, based on its type.
       auto argTy = mlirArg.getType();
       if (!argTy.isa<LLVM::LLVMPointerType>())
         return func.emitError(
             "llvm.align attribute attached to LLVM non-pointer argument");
       llvmArg.addAttrs(
-          llvm::AttrBuilder().addAlignmentAttr(llvm::Align(attr.getInt())));
+          llvm::AttrBuilder(llvmArg.getContext()).addAlignmentAttr(llvm::Align(attr.getInt())));
     }
 
     if (auto attr = func.getArgAttrOfType<UnitAttr>(argIdx, "llvm.sret")) {
       auto argTy = mlirArg.getType();
       if (!argTy.isa<LLVM::LLVMPointerType>())
         return func.emitError(
             "llvm.sret attribute attached to LLVM non-pointer argument");
-      llvmArg.addAttrs(llvm::AttrBuilder().addStructRetAttr(
+      llvmArg.addAttrs(llvm::AttrBuilder(llvmArg.getContext()).addStructRetAttr(
           llvmArg.getType()->getPointerElementType()));
     }
 
     if (auto attr = func.getArgAttrOfType<UnitAttr>(argIdx, "llvm.byval")) {
       auto argTy = mlirArg.getType();
       if (!argTy.isa<LLVM::LLVMPointerType>())
         return func.emitError(
             "llvm.byval attribute attached to LLVM non-pointer argument");
-      llvmArg.addAttrs(llvm::AttrBuilder().addByValAttr(
+      llvmArg.addAttrs(llvm::AttrBuilder(llvmArg.getContext()).addByValAttr(
           llvmArg.getType()->getPointerElementType()));
     }
 
     mapValue(mlirArg, &llvmArg);
     argIdx++;
   }
 
   // Check the personality and set it.
   if (func.getPersonality().hasValue()) {
     llvm::Type *ty = llvm::Type::getInt8PtrTy(llvmFunc->getContext());
     if (llvm::Constant *pfunc = getLLVMConstant(ty, func.getPersonalityAttr(),
                                                 func.getLoc(), *this))
       llvmFunc->setPersonalityFn(pfunc);
   }