[PATCH] D137960: [Lexer] Speedup LexTokenInternal

[serge via Phabricator via cfe-commits]

serge-sans-paille created this revision.
serge-sans-paille added reviewers: lattner, nikic.
Herald added a project: All.
serge-sans-paille requested review of this revision.
Herald added a project: clang.
Herald added a subscriber: cfe-commits.

Only reset "NeedsCleaning" flag in case of re-entrant call.
Do not needlessly blank IdentifierInfo. This information will be set
once the token type is picked.

This yields a nice 1% speedup when pre-processing sqlite amalgamation
through:

valgrind --tool=callgrind ./bin/clang -E sqlite3.c -o/dev/null


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D137960

Files:
  clang/lib/Lex/Lexer.cpp


Index: clang/lib/Lex/Lexer.cpp
===================================================================
--- clang/lib/Lex/Lexer.cpp
+++ clang/lib/Lex/Lexer.cpp
@@ -3516,10 +3516,8 @@
 /// token, not a normal token, as such, it is an internal interface.  It assumes
 /// that the Flags of result have been cleared before calling this.
 bool Lexer::LexTokenInternal(Token &Result, bool TokAtPhysicalStartOfLine) {
-LexNextToken:
-  // New token, can't need cleaning yet.
-  Result.clearFlag(Token::NeedsCleaning);
-  Result.setIdentifierInfo(nullptr);
+LexStart:
+  assert(!Result.needsCleaning() && "Result doesn't need cleaning");
 
   // CurPtr - Cache BufferPtr in an automatic variable.
   const char *CurPtr = BufferPtr;
@@ -4141,8 +4139,9 @@
       CurPtr = ConsumeChar(CurPtr, SizeTmp, Result);
     } else if (Char == '|') {
       // If this is '|||||||' and we're in a conflict marker, ignore it.
-      if (CurPtr[1] == '|' && HandleEndOfConflictMarker(CurPtr-1))
+      if (CurPtr[1] == '|' && HandleEndOfConflictMarker(CurPtr - 1)) {
         goto LexNextToken;
+      }
       Kind = tok::pipepipe;
       CurPtr = ConsumeChar(CurPtr, SizeTmp, Result);
     } else {
@@ -4170,8 +4169,9 @@
     Char = getCharAndSize(CurPtr, SizeTmp);
     if (Char == '=') {
       // If this is '====' and we're in a conflict marker, ignore it.
-      if (CurPtr[1] == '=' && HandleEndOfConflictMarker(CurPtr-1))
+      if (CurPtr[1] == '=' && HandleEndOfConflictMarker(CurPtr - 1)) {
         goto LexNextToken;
+      }
 
       Kind = tok::equalequal;
       CurPtr = ConsumeChar(CurPtr, SizeTmp, Result);
@@ -4301,6 +4301,10 @@
 
   // We parsed the directive; lex a token with the new state.
   return false;
+
+LexNextToken:
+  Result.clearFlag(Token::NeedsCleaning);
+  goto LexStart;
 }
 
 const char *Lexer::convertDependencyDirectiveToken(


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D137960.475181.patch
Type: text/x-patch
Size: 1842 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/cfe-commits/attachments/20221114/7dc9691a/attachment.bin>