[Driver] Use StringRef::operator== instead of StringRef::equals (NFC) (#91698)

I'm planning to remove StringRef::equals in favor of
StringRef::operator==.

- StringRef::operator==/!= outnumber StringRef::equals by a factor of
  13 under clang/ in terms of their usage.

- The elimination of StringRef::equals brings StringRef closer to
  std::string_view, which has operator== but not equals.

- S == "foo" is more readable than S.equals("foo"), especially for
  !Long.Expression.equals("str") vs Long.Expression != "str".

Author: kazutakahirata

clang/lib/Driver/Driver.cpp

@@ -564,9 +564,9 @@ static llvm::Triple computeTargetTriple(const Driver &D,
       StringRef ObjectMode = *ObjectModeValue;
       llvm::Triple::ArchType AT = llvm::Triple::UnknownArch;
 
-      if (ObjectMode.equals("64")) {
+      if (ObjectMode == "64") {
         AT = Target.get64BitArchVariant().getArch();
-      } else if (ObjectMode.equals("32")) {
+      } else if (ObjectMode == "32") {
         AT = Target.get32BitArchVariant().getArch();
       } else {
         D.Diag(diag::err_drv_invalid_object_mode) << ObjectMode;
@@ -6694,7 +6694,7 @@ llvm::StringRef clang::driver::getDriverMode(StringRef ProgName,
   return Opt.consume_front(OptName) ? Opt : "";
 }
 
-bool driver::IsClangCL(StringRef DriverMode) { return DriverMode.equals("cl"); }
+bool driver::IsClangCL(StringRef DriverMode) { return DriverMode == "cl"; }
 
 llvm::Error driver::expandResponseFiles(SmallVectorImpl<const char *> &Args,
                                         bool ClangCLMode,

clang/lib/Driver/ToolChains/AIX.cpp

@@ -481,8 +481,8 @@ static void addTocDataOptions(const llvm::opt::ArgList &Args,
 
   // Currently only supported for small code model.
   if (TOCDataGloballyinEffect &&
-      (Args.getLastArgValue(options::OPT_mcmodel_EQ).equals("large") ||
-       Args.getLastArgValue(options::OPT_mcmodel_EQ).equals("medium"))) {
+      (Args.getLastArgValue(options::OPT_mcmodel_EQ) == "large" ||
+       Args.getLastArgValue(options::OPT_mcmodel_EQ) == "medium")) {
     D.Diag(clang::diag::warn_drv_unsupported_tocdata);
     return;
   }

clang/lib/Driver/ToolChains/AMDGPU.cpp

@@ -732,7 +732,7 @@ AMDGPUToolChain::TranslateArgs(const DerivedArgList &Args, StringRef BoundArch,
 
   checkTargetID(*DAL);
 
-  if (!Args.getLastArgValue(options::OPT_x).equals("cl"))
+  if (Args.getLastArgValue(options::OPT_x) != "cl")
     return DAL;
 
   // Phase 1 (.cl -> .bc)

clang/lib/Driver/ToolChains/Clang.cpp

@@ -1526,7 +1526,7 @@ static void CollectARMPACBTIOptions(const ToolChain &TC, const ArgList &Args,
 
   CmdArgs.push_back(
       Args.MakeArgString(Twine("-msign-return-address=") + Scope));
-  if (!Scope.equals("none"))
+  if (Scope != "none")
     CmdArgs.push_back(
         Args.MakeArgString(Twine("-msign-return-address-key=") + Key));
   if (BranchProtectionPAuthLR)
@@ -1719,10 +1719,9 @@ void Clang::AddAArch64TargetArgs(const ArgList &Args,
   if (Arg *A = Args.getLastArg(options::OPT_msve_vector_bits_EQ)) {
     StringRef Val = A->getValue();
     const Driver &D = getToolChain().getDriver();
-    if (Val.equals("128") || Val.equals("256") || Val.equals("512") ||
-        Val.equals("1024") || Val.equals("2048") || Val.equals("128+") ||
-        Val.equals("256+") || Val.equals("512+") || Val.equals("1024+") ||
-        Val.equals("2048+")) {
+    if (Val == "128" || Val == "256" || Val == "512" || Val == "1024" ||
+        Val == "2048" || Val == "128+" || Val == "256+" || Val == "512+" ||
+        Val == "1024+" || Val == "2048+") {
       unsigned Bits = 0;
       if (!Val.consume_back("+")) {
         bool Invalid = Val.getAsInteger(10, Bits); (void)Invalid;
@@ -1736,7 +1735,7 @@ void Clang::AddAArch64TargetArgs(const ArgList &Args,
       CmdArgs.push_back(
           Args.MakeArgString("-mvscale-min=" + llvm::Twine(Bits / 128)));
     // Silently drop requests for vector-length agnostic code as it's implied.
-    } else if (!Val.equals("scalable"))
+    } else if (Val != "scalable")
       // Handle the unsupported values passed to msve-vector-bits.
       D.Diag(diag::err_drv_unsupported_option_argument)
           << A->getSpelling() << Val;
@@ -2098,7 +2097,7 @@ void Clang::AddRISCVTargetArgs(const ArgList &Args,
     // If the value is "zvl", use MinVLen from march. Otherwise, try to parse
     // as integer as long as we have a MinVLen.
     unsigned Bits = 0;
-    if (Val.equals("zvl") && MinVLen >= llvm::RISCV::RVVBitsPerBlock) {
+    if (Val == "zvl" && MinVLen >= llvm::RISCV::RVVBitsPerBlock) {
       Bits = MinVLen;
     } else if (!Val.getAsInteger(10, Bits)) {
       // Only accept power of 2 values beteen RVVBitsPerBlock and 65536 that
@@ -2115,7 +2114,7 @@ void Clang::AddRISCVTargetArgs(const ArgList &Args,
           Args.MakeArgString("-mvscale-max=" + llvm::Twine(VScaleMin)));
       CmdArgs.push_back(
           Args.MakeArgString("-mvscale-min=" + llvm::Twine(VScaleMin)));
-    } else if (!Val.equals("scalable")) {
+    } else if (Val != "scalable") {
       // Handle the unsupported values passed to mrvv-vector-bits.
       D.Diag(diag::err_drv_unsupported_option_argument)
           << A->getSpelling() << Val;
@@ -2865,13 +2864,13 @@ static void RenderFloatingPointOptions(const ToolChain &TC, const Driver &D,
     case options::OPT_fcomplex_arithmetic_EQ: {
       LangOptions::ComplexRangeKind RangeVal;
       StringRef Val = A->getValue();
-      if (Val.equals("full"))
+      if (Val == "full")
         RangeVal = LangOptions::ComplexRangeKind::CX_Full;
-      else if (Val.equals("improved"))
+      else if (Val == "improved")
         RangeVal = LangOptions::ComplexRangeKind::CX_Improved;
-      else if (Val.equals("promoted"))
+      else if (Val == "promoted")
         RangeVal = LangOptions::ComplexRangeKind::CX_Promoted;
-      else if (Val.equals("basic"))
+      else if (Val == "basic")
         RangeVal = LangOptions::ComplexRangeKind::CX_Basic;
       else {
         D.Diag(diag::err_drv_unsupported_option_argument)
@@ -2910,24 +2909,24 @@ static void RenderFloatingPointOptions(const ToolChain &TC, const Driver &D,
       FPContract = "on";
 
       StringRef Val = A->getValue();
-      if (OFastEnabled && !Val.equals("fast")) {
-          // Only -ffp-model=fast is compatible with OFast, ignore.
+      if (OFastEnabled && Val != "fast") {
+        // Only -ffp-model=fast is compatible with OFast, ignore.
         D.Diag(clang::diag::warn_drv_overriding_option)
             << Args.MakeArgString("-ffp-model=" + Val) << "-Ofast";
         break;
       }
       StrictFPModel = false;
-      if (!FPModel.empty() && !FPModel.equals(Val))
+      if (!FPModel.empty() && FPModel != Val)
         D.Diag(clang::diag::warn_drv_overriding_option)
             << Args.MakeArgString("-ffp-model=" + FPModel)
             << Args.MakeArgString("-ffp-model=" + Val);
-      if (Val.equals("fast")) {
+      if (Val == "fast") {
         FPModel = Val;
         applyFastMath();
-      } else if (Val.equals("precise")) {
+      } else if (Val == "precise") {
         FPModel = Val;
         FPContract = "on";
-      } else if (Val.equals("strict")) {
+      } else if (Val == "strict") {
         StrictFPModel = true;
         FPExceptionBehavior = "strict";
         FPModel = Val;
@@ -2957,7 +2956,7 @@ static void RenderFloatingPointOptions(const ToolChain &TC, const Driver &D,
     case options::OPT_fno_signed_zeros:     SignedZeros = false;      break;
     case options::OPT_ftrapping_math:
       if (!TrappingMathPresent && !FPExceptionBehavior.empty() &&
-          !FPExceptionBehavior.equals("strict"))
+          FPExceptionBehavior != "strict")
         // Warn that previous value of option is overridden.
         D.Diag(clang::diag::warn_drv_overriding_option)
             << Args.MakeArgString("-ffp-exception-behavior=" +
@@ -2969,7 +2968,7 @@ static void RenderFloatingPointOptions(const ToolChain &TC, const Driver &D,
       break;
     case options::OPT_fno_trapping_math:
       if (!TrappingMathPresent && !FPExceptionBehavior.empty() &&
-          !FPExceptionBehavior.equals("ignore"))
+          FPExceptionBehavior != "ignore")
         // Warn that previous value of option is overridden.
         D.Diag(clang::diag::warn_drv_overriding_option)
             << Args.MakeArgString("-ffp-exception-behavior=" +
@@ -3008,8 +3007,8 @@ static void RenderFloatingPointOptions(const ToolChain &TC, const Driver &D,
     // Validate and pass through -ffp-contract option.
     case options::OPT_ffp_contract: {
       StringRef Val = A->getValue();
-      if (Val.equals("fast") || Val.equals("on") || Val.equals("off") ||
-          Val.equals("fast-honor-pragmas")) {
+      if (Val == "fast" || Val == "on" || Val == "off" ||
+          Val == "fast-honor-pragmas") {
         FPContract = Val;
         LastSeenFfpContractOption = Val;
       } else
@@ -3022,16 +3021,16 @@ static void RenderFloatingPointOptions(const ToolChain &TC, const Driver &D,
     case options::OPT_ffp_exception_behavior_EQ: {
       StringRef Val = A->getValue();
       if (!TrappingMathPresent && !FPExceptionBehavior.empty() &&
-          !FPExceptionBehavior.equals(Val))
+          FPExceptionBehavior != Val)
         // Warn that previous value of option is overridden.
         D.Diag(clang::diag::warn_drv_overriding_option)
             << Args.MakeArgString("-ffp-exception-behavior=" +
                                   FPExceptionBehavior)
             << Args.MakeArgString("-ffp-exception-behavior=" + Val);
       TrappingMath = TrappingMathPresent = false;
-      if (Val.equals("ignore") || Val.equals("maytrap"))
+      if (Val == "ignore" || Val == "maytrap")
         FPExceptionBehavior = Val;
-      else if (Val.equals("strict")) {
+      else if (Val == "strict") {
         FPExceptionBehavior = Val;
         TrappingMath = TrappingMathPresent = true;
       } else
@@ -3043,8 +3042,7 @@ static void RenderFloatingPointOptions(const ToolChain &TC, const Driver &D,
     // Validate and pass through -ffp-eval-method option.
     case options::OPT_ffp_eval_method_EQ: {
       StringRef Val = A->getValue();
-      if (Val.equals("double") || Val.equals("extended") ||
-          Val.equals("source"))
+      if (Val == "double" || Val == "extended" || Val == "source")
         FPEvalMethod = Val;
       else
         D.Diag(diag::err_drv_unsupported_option_argument)
@@ -3056,18 +3054,18 @@ static void RenderFloatingPointOptions(const ToolChain &TC, const Driver &D,
       StringRef Val = A->getValue();
       const llvm::Triple::ArchType Arch = TC.getArch();
       if (Arch == llvm::Triple::x86 || Arch == llvm::Triple::x86_64) {
-        if (Val.equals("standard") || Val.equals("fast"))
+        if (Val == "standard" || Val == "fast")
           Float16ExcessPrecision = Val;
         // To make it GCC compatible, allow the value of "16" which
         // means disable excess precision, the same meaning than clang's
         // equivalent value "none".
-        else if (Val.equals("16"))
+        else if (Val == "16")
           Float16ExcessPrecision = "none";
         else
           D.Diag(diag::err_drv_unsupported_option_argument)
               << A->getSpelling() << Val;
       } else {
-        if (!(Val.equals("standard") || Val.equals("fast")))
+        if (!(Val == "standard" || Val == "fast"))
           D.Diag(diag::err_drv_unsupported_option_argument)
               << A->getSpelling() << Val;
       }
@@ -3149,7 +3147,7 @@ static void RenderFloatingPointOptions(const ToolChain &TC, const Driver &D,
       // subsequent options conflict then emit warning diagnostic.
       if (HonorINFs && HonorNaNs && !AssociativeMath && !ReciprocalMath &&
           SignedZeros && TrappingMath && RoundingFPMath && !ApproxFunc &&
-          FPContract.equals("off"))
+          FPContract == "off")
         // OK: Current Arg doesn't conflict with -ffp-model=strict
         ;
       else {
@@ -3195,7 +3193,7 @@ static void RenderFloatingPointOptions(const ToolChain &TC, const Driver &D,
 
   if (TrappingMath) {
     // FP Exception Behavior is also set to strict
-    assert(FPExceptionBehavior.equals("strict"));
+    assert(FPExceptionBehavior == "strict");
   }
 
   // The default is IEEE.
@@ -3244,8 +3242,8 @@ static void RenderFloatingPointOptions(const ToolChain &TC, const Driver &D,
   if (!HonorINFs && !HonorNaNs && !MathErrno && AssociativeMath && ApproxFunc &&
       ReciprocalMath && !SignedZeros && !TrappingMath && !RoundingFPMath) {
     CmdArgs.push_back("-ffast-math");
-    if (FPModel.equals("fast")) {
-      if (FPContract.equals("fast"))
+    if (FPModel == "fast") {
+      if (FPContract == "fast")
         // All set, do nothing.
         ;
       else if (FPContract.empty())

clang/lib/Driver/ToolChains/CommonArgs.cpp

@@ -346,7 +346,7 @@ void tools::addDirectoryList(const ArgList &Args, ArgStringList &CmdArgs,
     return; // Nothing to do.
 
   StringRef Name(ArgName);
-  if (Name.equals("-I") || Name.equals("-L") || Name.empty())
+  if (Name == "-I" || Name == "-L" || Name.empty())
     CombinedArg = true;
 
   StringRef Dirs(DirList);

clang/lib/Driver/ToolChains/Flang.cpp

@@ -170,10 +170,9 @@ void Flang::AddAArch64TargetArgs(const ArgList &Args,
   if (Arg *A = Args.getLastArg(options::OPT_msve_vector_bits_EQ)) {
     StringRef Val = A->getValue();
     const Driver &D = getToolChain().getDriver();
-    if (Val.equals("128") || Val.equals("256") || Val.equals("512") ||
-        Val.equals("1024") || Val.equals("2048") || Val.equals("128+") ||
-        Val.equals("256+") || Val.equals("512+") || Val.equals("1024+") ||
-        Val.equals("2048+")) {
+    if (Val == "128" || Val == "256" || Val == "512" || Val == "1024" ||
+        Val == "2048" || Val == "128+" || Val == "256+" || Val == "512+" ||
+        Val == "1024+" || Val == "2048+") {
       unsigned Bits = 0;
       if (!Val.consume_back("+")) {
         [[maybe_unused]] bool Invalid = Val.getAsInteger(10, Bits);
@@ -187,7 +186,7 @@ void Flang::AddAArch64TargetArgs(const ArgList &Args,
       CmdArgs.push_back(
           Args.MakeArgString("-mvscale-min=" + llvm::Twine(Bits / 128)));
       // Silently drop requests for vector-length agnostic code as it's implied.
-    } else if (!Val.equals("scalable"))
+    } else if (Val != "scalable")
       // Handle the unsupported values passed to msve-vector-bits.
       D.Diag(diag::err_drv_unsupported_option_argument)
           << A->getSpelling() << Val;
@@ -214,7 +213,7 @@ void Flang::AddRISCVTargetArgs(const ArgList &Args,
     // If the value is "zvl", use MinVLen from march. Otherwise, try to parse
     // as integer as long as we have a MinVLen.
     unsigned Bits = 0;
-    if (Val.equals("zvl") && MinVLen >= llvm::RISCV::RVVBitsPerBlock) {
+    if (Val == "zvl" && MinVLen >= llvm::RISCV::RVVBitsPerBlock) {
       Bits = MinVLen;
     } else if (!Val.getAsInteger(10, Bits)) {
       // Only accept power of 2 values beteen RVVBitsPerBlock and 65536 that
@@ -231,7 +230,7 @@ void Flang::AddRISCVTargetArgs(const ArgList &Args,
           Args.MakeArgString("-mvscale-max=" + llvm::Twine(VScaleMin)));
       CmdArgs.push_back(
           Args.MakeArgString("-mvscale-min=" + llvm::Twine(VScaleMin)));
-    } else if (!Val.equals("scalable")) {
+    } else if (Val != "scalable") {
       // Handle the unsupported values passed to mrvv-vector-bits.
       D.Diag(diag::err_drv_unsupported_option_argument)
           << A->getSpelling() << Val;