Use a sorted array instead of a map to store AttrBuilder string attributes

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

Differential Revision: https://reviews.llvm.org/D116599

1 files changed, 4 insertions, 4 deletions

diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 79e7197d0e0a..6d6f154f45bf 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -1819,7 +1819,7 @@ CodeGenModule::getMostBaseClasses(const CXXRecordDecl *RD) {
 
 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);
@@ -1982,7 +1982,7 @@ void CodeGenModule::SetLLVMFunctionAttributesForDefinition(const Decl *D,
 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);
   }
@@ -2092,7 +2092,7 @@ void CodeGenModule::setNonAliasAttributes(GlobalDecl GD,
         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
@@ -3785,7 +3785,7 @@ llvm::Constant *CodeGenModule::GetOrCreateLLVMFunction(
   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);
   }