[ELF] Replace inExpr with lexState. NFC

We may add another state State::Wild to behave more lik GNU ld.

Author: MaskRay

lld/ELF/ScriptLexer.cpp

@@ -105,7 +105,7 @@ void ScriptLexer::lex() {
       curBuf = buffers.pop_back_val();
       continue;
     }
-    curTokState = inExpr;
+    curTokState = lexState;
 
     // Quoted token. Note that double-quote characters are parts of a token
     // because, in a glob match context, only unquoted tokens are interpreted
@@ -142,18 +142,21 @@ void ScriptLexer::lex() {
     // C-like languages, so that you can write "file-name.cpp" as one bare
     // token.
     size_t pos;
-    if (inExpr) {
+    switch (lexState) {
+    case State::Script:
+      pos = s.find_first_not_of(
+          "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
+          "0123456789_.$/\\~=+[]*?-!^:");
+      break;
+    case State::Expr:
       pos = s.find_first_not_of(
           "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
           "0123456789_.$");
       if (pos == 0 && s.size() >= 2 &&
           ((s[0] == s[1] && strchr("<>&|", s[0])) ||
            is_contained({"==", "!=", "<=", ">=", "<<", ">>"}, s.substr(0, 2))))
         pos = 2;
-    } else {
-      pos = s.find_first_not_of(
-          "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
-          "0123456789_.$/\\~=+[]*?-!^:");
+      break;
     }
 
     if (pos == 0)
@@ -208,8 +211,8 @@ StringRef ScriptLexer::next() {
 }
 
 StringRef ScriptLexer::peek() {
-  // curTok is invalid if curTokState and inExpr mismatch.
-  if (curTok.size() && curTokState != inExpr) {
+  // curTok is invalid if curTokState and lexState mismatch.
+  if (curTok.size() && curTokState != lexState) {
     curBuf.s = StringRef(curTok.data(), curBuf.s.end() - curTok.data());
     curTok = {};
   }

lld/ELF/ScriptLexer.h

@@ -41,6 +41,11 @@ class ScriptLexer {
   // Used to detect INCLUDE() cycles.
   llvm::DenseSet<StringRef> activeFilenames;
 
+  enum class State {
+    Script,
+    Expr,
+  };
+
   struct Token {
     StringRef str;
     explicit operator bool() const { return !str.empty(); }
@@ -54,8 +59,9 @@ class ScriptLexer {
   // expression state changes.
   StringRef curTok;
   size_t prevTokLine = 1;
-  // The inExpr state when curTok is cached.
-  bool curTokState = false;
+  // The lex state when curTok is cached.
+  State curTokState = State::Script;
+  State lexState = State::Script;
   bool eof = false;
 
 public:
@@ -75,7 +81,6 @@ class ScriptLexer {
   MemoryBufferRef getCurrentMB();
 
   std::vector<MemoryBufferRef> mbs;
-  bool inExpr = false;
 
 private:
   StringRef getLine();

lld/ELF/ScriptParser.cpp

@@ -289,7 +289,7 @@ void ScriptParser::readLinkerScript() {
 void ScriptParser::readDefsym() {
   if (errCount(ctx))
     return;
-  inExpr = true;
+  SaveAndRestore saved(lexState, State::Expr);
   StringRef name = readName();
   expect("=");
   Expr e = readExpr();
@@ -954,8 +954,8 @@ bool ScriptParser::readSectionDirective(OutputSection *cmd, StringRef tok) {
 // https://sourceware.org/binutils/docs/ld/Output-Section-Type.html
 void ScriptParser::readSectionAddressType(OutputSection *cmd) {
   if (consume("(")) {
-    // Temporarily set inExpr to support TYPE=<value> without spaces.
-    SaveAndRestore saved(inExpr, true);
+    // Temporarily set lexState to support TYPE=<value> without spaces.
+    SaveAndRestore saved(lexState, State::Expr);
     if (readSectionDirective(cmd, peek()))
       return;
     cmd->addrExpr = readExpr();
@@ -965,7 +965,7 @@ void ScriptParser::readSectionAddressType(OutputSection *cmd) {
   }
 
   if (consume("(")) {
-    SaveAndRestore saved(inExpr, true);
+    SaveAndRestore saved(lexState, State::Expr);
     StringRef tok = peek();
     if (!readSectionDirective(cmd, tok))
       setError("unknown section directive: " + tok);
@@ -1087,10 +1087,10 @@ OutputDesc *ScriptParser::readOutputSectionDescription(StringRef outSec) {
   osec->phdrs = readOutputSectionPhdrs();
 
   if (peek() == "=" || peek().starts_with("=")) {
-    inExpr = true;
+    lexState = State::Expr;
     consume("=");
     osec->filler = readFill();
-    inExpr = false;
+    lexState = State::Script;
   }
 
   // Consume optional comma following output section command.
@@ -1162,7 +1162,7 @@ SymbolAssignment *ScriptParser::readAssignment(StringRef tok) {
   bool savedSeenRelroEnd = ctx.script->seenRelroEnd;
   const StringRef op = peek();
   {
-    SaveAndRestore saved(inExpr, true);
+    SaveAndRestore saved(lexState, State::Expr);
     if (op.starts_with("=")) {
       // Support = followed by an expression without whitespace.
       cmd = readSymbolAssignment(unquote(tok));
@@ -1235,7 +1235,7 @@ SymbolAssignment *ScriptParser::readSymbolAssignment(StringRef name) {
 Expr ScriptParser::readExpr() {
   // Our lexer is context-aware. Set the in-expression bit so that
   // they apply different tokenization rules.
-  SaveAndRestore saved(inExpr, true);
+  SaveAndRestore saved(lexState, State::Expr);
   Expr e = readExpr1(readPrimary(), 0);
   return e;
 }
@@ -1452,12 +1452,11 @@ std::pair<uint64_t, uint64_t> ScriptParser::readInputSectionFlags() {
 
 StringRef ScriptParser::readParenName() {
   expect("(");
-  bool orig = inExpr;
-  inExpr = false;
-  StringRef tok = readName();
-  inExpr = orig;
+  auto saved = std::exchange(lexState, State::Script);
+  StringRef name = readName();
+  lexState = saved;
   expect(")");
-  return tok;
+  return name;
 }
 
 static void checkIfExists(LinkerScript &script, const OutputSection &osec,