[NFC][Clang] Use StringSwitch instead of array for parsing attribute scope

Change-Id: Iacfabcfd3a1cedeb7c864b3b59bad88b2177e7a8

Author: chinmaydd

clang/include/clang/Basic/AttributeCommonInfo.h

@@ -67,7 +67,7 @@ class AttributeCommonInfo {
     IgnoredAttribute,
     UnknownAttribute,
   };
-  enum class Scope { NONE, CLANG, GNU, MSVC, OMP, HLSL, GSL, RISCV };
+  enum class Scope { NONE, CLANG, GNU, MSVC, OMP, HLSL, GSL, RISCV, INVALID };
 
 private:
   const IdentifierInfo *AttrName = nullptr;

clang/lib/Basic/Attributes.cpp

@@ -18,6 +18,7 @@
 #include "clang/Basic/TargetInfo.h"
 
 #include "llvm/ADT/StringMap.h"
+#include "llvm/ADT/StringSwitch.h"
 
 using namespace clang;
 
@@ -155,26 +156,23 @@ std::string AttributeCommonInfo::getNormalizedFullName() const {
       normalizeName(getAttrName(), getScopeName(), getSyntax()));
 }
 
-// Sorted list of attribute scope names
-static constexpr std::pair<StringRef, AttributeCommonInfo::Scope> ScopeList[] =
-    {{"", AttributeCommonInfo::Scope::NONE},
-     {"clang", AttributeCommonInfo::Scope::CLANG},
-     {"gnu", AttributeCommonInfo::Scope::GNU},
-     {"gsl", AttributeCommonInfo::Scope::GSL},
-     {"hlsl", AttributeCommonInfo::Scope::HLSL},
-     {"msvc", AttributeCommonInfo::Scope::MSVC},
-     {"omp", AttributeCommonInfo::Scope::OMP},
-     {"riscv", AttributeCommonInfo::Scope::RISCV}};
-
 AttributeCommonInfo::Scope
 getScopeFromNormalizedScopeName(StringRef ScopeName) {
-  auto It = std::lower_bound(
-      std::begin(ScopeList), std::end(ScopeList), ScopeName,
-      [](const std::pair<StringRef, AttributeCommonInfo::Scope> &Element,
-         StringRef Value) { return Element.first < Value; });
-  assert(It != std::end(ScopeList) && It->first == ScopeName);
-
-  return It->second;
+  AttributeCommonInfo::Scope ParsedScope =
+      llvm::StringSwitch<AttributeCommonInfo::Scope>(ScopeName)
+          .Case("", AttributeCommonInfo::Scope::NONE)
+          .Case("clang", AttributeCommonInfo::Scope::CLANG)
+          .Case("gnu", AttributeCommonInfo::Scope::GNU)
+          .Case("gsl", AttributeCommonInfo::Scope::GSL)
+          .Case("hlsl", AttributeCommonInfo::Scope::HLSL)
+          .Case("msvc", AttributeCommonInfo::Scope::MSVC)
+          .Case("omp", AttributeCommonInfo::Scope::OMP)
+          .Case("riscv", AttributeCommonInfo::Scope::RISCV)
+          .Default(AttributeCommonInfo::Scope::INVALID);
+
+  assert(ParsedScope != AttributeCommonInfo::Scope::INVALID);
+
+  return ParsedScope;
 }
 
 unsigned AttributeCommonInfo::calculateAttributeSpellingListIndex() const {