[clang] Use a StringRef instead of a raw char pointer to store builtin and call information

This avoids recomputing string length that is already known at compile
time.

It has a slight impact on preprocessing / compile time, see

https://llvm-compile-time-tracker.com/compare.php?from=3f36d2d579d8b0e8824d9dd99bfa79f456858f88&to=e49640c507ddc6615b5e503144301c8e41f8f434&stat=instructions:u

Differential Revision: https://reviews.llvm.org/D139881

Author: serge-sans-paille

clang-tools-extra/clangd/CompileCommands.cpp

@@ -466,8 +466,10 @@ llvm::ArrayRef<ArgStripper::Rule> ArgStripper::rulesFor(llvm::StringRef Arg) {
       NextAlias[T] = Self;
     };
     // Also grab prefixes for each option, these are not fully exposed.
-    const char *const *Prefixes[DriverID::LastOption] = {nullptr};
-#define PREFIX(NAME, VALUE) static const char *const NAME[] = VALUE;
+    std::initializer_list<llvm::StringLiteral> Prefixes[DriverID::LastOption];
+
+#define PREFIX(NAME, VALUE)                                                    \
+  static constexpr std::initializer_list<llvm::StringLiteral> NAME = VALUE;
 #define OPTION(PREFIX, NAME, ID, KIND, GROUP, ALIAS, ALIASARGS, FLAGS, PARAM,  \
                HELP, METAVAR, VALUES)                                          \
   Prefixes[DriverID::OPT_##ID] = PREFIX;
@@ -499,7 +501,7 @@ llvm::ArrayRef<ArgStripper::Rule> ArgStripper::rulesFor(llvm::StringRef Arg) {
       llvm::SmallVector<Rule> Rules;
       // Iterate over each alias, to add rules for parsing it.
       for (unsigned A = ID; A != DriverID::OPT_INVALID; A = NextAlias[A]) {
-        if (Prefixes[A] == nullptr) // option groups.
+        if (!Prefixes[A].size()) // option groups.
           continue;
         auto Opt = DriverTable.getOption(A);
         // Exclude - and -foo pseudo-options.
@@ -508,8 +510,8 @@ llvm::ArrayRef<ArgStripper::Rule> ArgStripper::rulesFor(llvm::StringRef Arg) {
         auto Modes = getModes(Opt);
         std::pair<unsigned, unsigned> ArgCount = getArgCount(Opt);
         // Iterate over each spelling of the alias, e.g. -foo vs --foo.
-        for (auto *Prefix = Prefixes[A]; *Prefix != nullptr; ++Prefix) {
-          llvm::SmallString<64> Buf(*Prefix);
+        for (StringRef Prefix : Prefixes[A]) {
+          llvm::SmallString<64> Buf(Prefix);
           Buf.append(Opt.getName());
           llvm::StringRef Spelling = Result->try_emplace(Buf).first->getKey();
           Rules.emplace_back();

clang/include/clang/Basic/Builtins.h

@@ -57,7 +57,8 @@ enum ID {
 };
 
 struct Info {
-  const char *Name, *Type, *Attributes, *HeaderName;
+  llvm::StringRef Name;
+  const char *Type, *Attributes, *HeaderName;
   LanguageID Langs;
   const char *Features;
 };
@@ -86,9 +87,7 @@ class Context {
 
   /// Return the identifier name for the specified builtin,
   /// e.g. "__builtin_abs".
-  const char *getName(unsigned ID) const {
-    return getRecord(ID).Name;
-  }
+  llvm::StringRef getName(unsigned ID) const { return getRecord(ID).Name; }
 
   /// Get the type descriptor string for the specified builtin.
   const char *getTypeString(unsigned ID) const {

clang/include/clang/StaticAnalyzer/Core/PathSensitive/CallDescription.h

@@ -63,13 +63,12 @@ class CallDescription {
   /// @param RequiredArgs The number of arguments that is expected to match a
   /// call. Omit this parameter to match every occurrence of call with a given
   /// name regardless the number of arguments.
-  CallDescription(CallDescriptionFlags Flags,
-                  ArrayRef<const char *> QualifiedName,
+  CallDescription(CallDescriptionFlags Flags, ArrayRef<StringRef> QualifiedName,
                   MaybeCount RequiredArgs = std::nullopt,
                   MaybeCount RequiredParams = std::nullopt);
 
   /// Construct a CallDescription with default flags.
-  CallDescription(ArrayRef<const char *> QualifiedName,
+  CallDescription(ArrayRef<StringRef> QualifiedName,
                   MaybeCount RequiredArgs = std::nullopt,
                   MaybeCount RequiredParams = std::nullopt);
 

clang/lib/AST/ExprConstant.cpp

@@ -9242,8 +9242,8 @@ bool PointerExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E,
   case Builtin::BIwmemchr:
     if (Info.getLangOpts().CPlusPlus11)
       Info.CCEDiag(E, diag::note_constexpr_invalid_function)
-        << /*isConstexpr*/0 << /*isConstructor*/0
-        << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'");
+          << /*isConstexpr*/ 0 << /*isConstructor*/ 0
+          << ("'" + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'").str();
     else
       Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr);
     [[fallthrough]];
@@ -9288,7 +9288,7 @@ bool PointerExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E,
     // FIXME: We can compare the bytes in the correct order.
     if (IsRawByte && !isOneByteCharacterType(CharTy)) {
       Info.FFDiag(E, diag::note_constexpr_memchr_unsupported)
-          << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'")
+          << ("'" + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'").str()
           << CharTy;
       return false;
     }
@@ -9350,8 +9350,8 @@ bool PointerExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E,
   case Builtin::BIwmemmove:
     if (Info.getLangOpts().CPlusPlus11)
       Info.CCEDiag(E, diag::note_constexpr_invalid_function)
-        << /*isConstexpr*/0 << /*isConstructor*/0
-        << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'");
+          << /*isConstexpr*/ 0 << /*isConstructor*/ 0
+          << ("'" + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'").str();
     else
       Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr);
     [[fallthrough]];
@@ -12209,8 +12209,8 @@ bool IntExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E,
     // A call to strlen is not a constant expression.
     if (Info.getLangOpts().CPlusPlus11)
       Info.CCEDiag(E, diag::note_constexpr_invalid_function)
-        << /*isConstexpr*/0 << /*isConstructor*/0
-        << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'");
+          << /*isConstexpr*/ 0 << /*isConstructor*/ 0
+          << ("'" + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'").str();
     else
       Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr);
     [[fallthrough]];
@@ -12234,8 +12234,8 @@ bool IntExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E,
     // A call to strlen is not a constant expression.
     if (Info.getLangOpts().CPlusPlus11)
       Info.CCEDiag(E, diag::note_constexpr_invalid_function)
-        << /*isConstexpr*/0 << /*isConstructor*/0
-        << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'");
+          << /*isConstexpr*/ 0 << /*isConstructor*/ 0
+          << ("'" + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'").str();
     else
       Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr);
     [[fallthrough]];
@@ -12290,7 +12290,7 @@ bool IntExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E,
         !(isOneByteCharacterType(CharTy1) && isOneByteCharacterType(CharTy2))) {
       // FIXME: Consider using our bit_cast implementation to support this.
       Info.FFDiag(E, diag::note_constexpr_memcmp_unsupported)
-          << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'")
+          << ("'" + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'").str()
           << CharTy1 << CharTy2;
       return false;
     }

clang/lib/Basic/Builtins.cpp

@@ -18,8 +18,9 @@
 #include "llvm/ADT/StringRef.h"
 using namespace clang;
 
-static const Builtin::Info BuiltinInfo[] = {
-  { "not a builtin function", nullptr, nullptr, nullptr, ALL_LANGUAGES,nullptr},
+static constexpr Builtin::Info BuiltinInfo[] = {
+    {"not a builtin function", nullptr, nullptr, nullptr, ALL_LANGUAGES,
+     nullptr},
 #define BUILTIN(ID, TYPE, ATTRS)                                               \
   { #ID, TYPE, ATTRS, nullptr, ALL_LANGUAGES, nullptr },
 #define LANGBUILTIN(ID, TYPE, ATTRS, LANGS)                                    \

clang/lib/CodeGen/CGBuiltin.cpp

@@ -134,7 +134,7 @@ llvm::Constant *CodeGenModule::getBuiltinLibFunction(const FunctionDecl *FD,
                  AIXLongDouble64Builtins.end())
       Name = AIXLongDouble64Builtins[BuiltinID];
     else
-      Name = Context.BuiltinInfo.getName(BuiltinID) + 10;
+      Name = Context.BuiltinInfo.getName(BuiltinID).substr(10);
   }
 
   llvm::FunctionType *Ty =
@@ -5302,7 +5302,7 @@ RValue CodeGenFunction::EmitBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID,
     LargestVectorWidth = std::max(LargestVectorWidth, VectorWidth);
 
   // See if we have a target specific intrinsic.
-  const char *Name = getContext().BuiltinInfo.getName(BuiltinID);
+  StringRef Name = getContext().BuiltinInfo.getName(BuiltinID);
   Intrinsic::ID IntrinsicID = Intrinsic::not_intrinsic;
   StringRef Prefix =
       llvm::Triple::getArchTypePrefix(getTarget().getTriple().getArch());

clang/lib/Driver/DriverOptions.cpp

@@ -16,11 +16,12 @@ using namespace clang::driver;
 using namespace clang::driver::options;
 using namespace llvm::opt;
 
-#define PREFIX(NAME, VALUE) static const char *const NAME[] = VALUE;
+#define PREFIX(NAME, VALUE)                                                    \
+  static constexpr std::initializer_list<llvm::StringLiteral> NAME = VALUE;
 #include "clang/Driver/Options.inc"
 #undef PREFIX
 
-static constexpr  OptTable::Info InfoTable[] = {
+static constexpr std::initializer_list<OptTable::Info> InfoTable = {
 #define OPTION(PREFIX, NAME, ID, KIND, GROUP, ALIAS, ALIASARGS, FLAGS, PARAM,  \
                HELPTEXT, METAVAR, VALUES)                                      \
   {PREFIX, NAME,  HELPTEXT,    METAVAR,     OPT_##ID,  Option::KIND##Class,    \

clang/lib/Sema/SemaChecking.cpp

@@ -6956,7 +6956,7 @@ Sema::SemaBuiltinAtomicOverloaded(ExprResult TheCallResult) {
   // Get the decl for the concrete builtin from this, we can tell what the
   // concrete integer type we should convert to is.
   unsigned NewBuiltinID = BuiltinIndices[BuiltinIndex][SizeIndex];
-  const char *NewBuiltinName = Context.BuiltinInfo.getName(NewBuiltinID);
+  StringRef NewBuiltinName = Context.BuiltinInfo.getName(NewBuiltinID);
   FunctionDecl *NewBuiltinDecl;
   if (NewBuiltinID == BuiltinID)
     NewBuiltinDecl = FDecl;
@@ -11008,7 +11008,7 @@ static void emitReplacement(Sema &S, SourceLocation Loc, SourceRange Range,
                             unsigned AbsKind, QualType ArgType) {
   bool EmitHeaderHint = true;
   const char *HeaderName = nullptr;
-  const char *FunctionName = nullptr;
+  StringRef FunctionName;
   if (S.getLangOpts().CPlusPlus && !ArgType->isAnyComplexType()) {
     FunctionName = "std::abs";
     if (ArgType->isIntegralOrEnumerationType()) {
@@ -11116,7 +11116,7 @@ void Sema::CheckAbsoluteValueFunction(const CallExpr *Call,
   // Unsigned types cannot be negative.  Suggest removing the absolute value
   // function call.
   if (ArgType->isUnsignedIntegerType()) {
-    const char *FunctionName =
+    StringRef FunctionName =
         IsStdAbs ? "std::abs" : Context.BuiltinInfo.getName(AbsKind);
     Diag(Call->getExprLoc(), diag::warn_unsigned_abs) << ArgType << ParamType;
     Diag(Call->getExprLoc(), diag::note_remove_abs)

clang/lib/StaticAnalyzer/Checkers/BasicObjCFoundationChecks.cpp

@@ -532,10 +532,10 @@ namespace {
 class CFRetainReleaseChecker : public Checker<check::PreCall> {
   mutable APIMisuse BT{this, "null passed to CF memory management function"};
   const CallDescriptionSet ModelledCalls = {
-      {"CFRetain", 1},
-      {"CFRelease", 1},
-      {"CFMakeCollectable", 1},
-      {"CFAutorelease", 1},
+      {{"CFRetain"}, 1},
+      {{"CFRelease"}, 1},
+      {{"CFMakeCollectable"}, 1},
+      {{"CFAutorelease"}, 1},
   };
 
 public:

clang/lib/StaticAnalyzer/Checkers/BlockInCriticalSectionChecker.cpp

@@ -64,19 +64,15 @@ class BlockInCriticalSectionChecker : public Checker<check::PostCall> {
 REGISTER_TRAIT_WITH_PROGRAMSTATE(MutexCounter, unsigned)
 
 BlockInCriticalSectionChecker::BlockInCriticalSectionChecker()
-    : IILockGuard(nullptr), IIUniqueLock(nullptr),
-      LockFn("lock"), UnlockFn("unlock"), SleepFn("sleep"), GetcFn("getc"),
-      FgetsFn("fgets"), ReadFn("read"), RecvFn("recv"),
-      PthreadLockFn("pthread_mutex_lock"),
-      PthreadTryLockFn("pthread_mutex_trylock"),
-      PthreadUnlockFn("pthread_mutex_unlock"),
-      MtxLock("mtx_lock"),
-      MtxTimedLock("mtx_timedlock"),
-      MtxTryLock("mtx_trylock"),
-      MtxUnlock("mtx_unlock"),
-      ClassLockGuard("lock_guard"),
-      ClassUniqueLock("unique_lock"),
-      IdentifierInfoInitialized(false) {
+    : IILockGuard(nullptr), IIUniqueLock(nullptr), LockFn({"lock"}),
+      UnlockFn({"unlock"}), SleepFn({"sleep"}), GetcFn({"getc"}),
+      FgetsFn({"fgets"}), ReadFn({"read"}), RecvFn({"recv"}),
+      PthreadLockFn({"pthread_mutex_lock"}),
+      PthreadTryLockFn({"pthread_mutex_trylock"}),
+      PthreadUnlockFn({"pthread_mutex_unlock"}), MtxLock({"mtx_lock"}),
+      MtxTimedLock({"mtx_timedlock"}), MtxTryLock({"mtx_trylock"}),
+      MtxUnlock({"mtx_unlock"}), ClassLockGuard("lock_guard"),
+      ClassUniqueLock("unique_lock"), IdentifierInfoInitialized(false) {
   // Initialize the bug type.
   BlockInCritSectionBugType.reset(
       new BugType(this, "Call to blocking function in critical section",