[llvm] Prefer StringRef::substr to StringRef::slice (NFC) (#106190)

S.substr(N, M) is simpler than S.slice(N, N + M).  Also, substr is
probably better recognizable than slice thanks to
std::string_view::substr.

Author: kazutakahirata

llvm/lib/MC/MCParser/AsmParser.cpp

@@ -5784,7 +5784,7 @@ bool AsmParser::parseDirectiveIrpc(SMLoc DirectiveLoc) {
                                                   : A[0][0].getString();
   for (std::size_t I = 0, End = Values.size(); I != End; ++I) {
     MCAsmMacroArgument Arg;
-    Arg.emplace_back(AsmToken::Identifier, Values.slice(I, I + 1));
+    Arg.emplace_back(AsmToken::Identifier, Values.substr(I, 1));
 
     // Note that the AtPseudoVariable is enabled for instantiations of .irpc.
     // This is undocumented, but GAS seems to support it.

llvm/lib/MC/MCParser/MasmParser.cpp

@@ -7125,7 +7125,7 @@ bool MasmParser::parseDirectiveForc(SMLoc DirectiveLoc, StringRef Directive) {
   StringRef Values(Argument);
   for (std::size_t I = 0, End = Values.size(); I != End; ++I) {
     MCAsmMacroArgument Arg;
-    Arg.emplace_back(AsmToken::Identifier, Values.slice(I, I + 1));
+    Arg.emplace_back(AsmToken::Identifier, Values.substr(I, 1));
 
     if (expandMacro(OS, M->Body, Parameter, Arg, M->Locals, getTok().getLoc()))
       return true;

llvm/lib/Object/COFFObjectFile.cpp

@@ -2369,7 +2369,7 @@ ResourceSectionRef::getContents(const coff_resource_data_entry &Entry) {
         Expected<StringRef> Contents = S.getContents();
         if (!Contents)
           return Contents.takeError();
-        return Contents->slice(Offset, Offset + Entry.DataSize);
+        return Contents->substr(Offset, Entry.DataSize);
       }
     }
     return createStringError(object_error::parse_failed,

llvm/lib/Object/MachOObjectFile.cpp

@@ -2099,7 +2099,7 @@ ArrayRef<uint8_t> getSegmentContents(const MachOObjectFile &Obj,
   }
   auto &Segment = SegmentOrErr.get();
   return arrayRefFromStringRef(
-      Obj.getData().slice(Segment.fileoff, Segment.fileoff + Segment.filesize));
+      Obj.getData().substr(Segment.fileoff, Segment.filesize));
 }
 } // namespace
 
@@ -2454,9 +2454,8 @@ StringRef MachOObjectFile::guessLibraryShortName(StringRef Name,
     Idx = 0;
   else
     Idx = b+1;
-  F = Name.slice(Idx, Idx + Foo.size());
-  DotFramework = Name.slice(Idx + Foo.size(),
-                            Idx + Foo.size() + sizeof(".framework/")-1);
+  F = Name.substr(Idx, Foo.size());
+  DotFramework = Name.substr(Idx + Foo.size(), sizeof(".framework/") - 1);
   if (F == Foo && DotFramework == ".framework/") {
     isFramework = true;
     return Foo;
@@ -2476,9 +2475,8 @@ StringRef MachOObjectFile::guessLibraryShortName(StringRef Name,
     Idx = 0;
   else
     Idx = d+1;
-  F = Name.slice(Idx, Idx + Foo.size());
-  DotFramework = Name.slice(Idx + Foo.size(),
-                            Idx + Foo.size() + sizeof(".framework/")-1);
+  F = Name.substr(Idx, Foo.size());
+  DotFramework = Name.substr(Idx + Foo.size(), sizeof(".framework/") - 1);
   if (F == Foo && DotFramework == ".framework/") {
     isFramework = true;
     return Foo;
@@ -2495,7 +2493,7 @@ StringRef MachOObjectFile::guessLibraryShortName(StringRef Name,
 
   // First pull off the version letter for the form Foo.A.dylib if any.
   if (a >= 3) {
-    Dot = Name.slice(a-2, a-1);
+    Dot = Name.substr(a - 2, 1);
     if (Dot == ".")
       a = a - 2;
   }
@@ -2520,7 +2518,7 @@ StringRef MachOObjectFile::guessLibraryShortName(StringRef Name,
   // There are incorrect library names of the form:
   // libATS.A_profile.dylib so check for these.
   if (Lib.size() >= 3) {
-    Dot = Lib.slice(Lib.size()-2, Lib.size()-1);
+    Dot = Lib.substr(Lib.size() - 2, 1);
     if (Dot == ".")
       Lib = Lib.slice(0, Lib.size()-2);
   }
@@ -2537,7 +2535,7 @@ StringRef MachOObjectFile::guessLibraryShortName(StringRef Name,
     Lib = Name.slice(b+1, a);
   // There are library names of the form: QT.A.qtx so check for these.
   if (Lib.size() >= 3) {
-    Dot = Lib.slice(Lib.size()-2, Lib.size()-1);
+    Dot = Lib.substr(Lib.size() - 2, 1);
     if (Dot == ".")
       Lib = Lib.slice(0, Lib.size()-2);
   }

llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp

@@ -1956,7 +1956,7 @@ bool X86AsmParser::ParseIntelExpression(IntelExprStateMachine &SM, SMLoc &End) {
         if (DotOffset != StringRef::npos) {
           consumeToken();
           StringRef LHS = Identifier.slice(0, DotOffset);
-          StringRef Dot = Identifier.slice(DotOffset, DotOffset + 1);
+          StringRef Dot = Identifier.substr(DotOffset, 1);
           StringRef RHS = Identifier.substr(DotOffset + 1);
           if (!RHS.empty()) {
             getLexer().UnLex(AsmToken(AsmToken::Identifier, RHS));

llvm/utils/TableGen/AsmMatcherEmitter.cpp

@@ -1013,7 +1013,7 @@ void MatchableInfo::tokenizeAsmString(const AsmMatcherInfo &Info,
         InTok = false;
         IsIsolatedToken = false;
       }
-      addAsmOperand(String.slice(i, i + 1), IsIsolatedToken);
+      addAsmOperand(String.substr(i, 1), IsIsolatedToken);
       Prev = i + 1;
       IsIsolatedToken = true;
       continue;
@@ -1037,7 +1037,7 @@ void MatchableInfo::tokenizeAsmString(const AsmMatcherInfo &Info,
       }
       ++i;
       assert(i != String.size() && "Invalid quoted character");
-      addAsmOperand(String.slice(i, i + 1), IsIsolatedToken);
+      addAsmOperand(String.substr(i, 1), IsIsolatedToken);
       Prev = i + 1;
       IsIsolatedToken = false;
       break;