From 5e79ee087e9eacc311d4abca736c734fb1012f18 Mon Sep 17 00:00:00 2001 From: Craig Topper Date: Fri, 19 Oct 2012 04:40:38 +0000 Subject: [PATCH] Teach getColumnNumber to use the line cache to get the start of the line if its on the same line as the last call to getLineNumber. Prevents needing to scan backwards for the new line. Fixes PR14106. llvm-svn: 166265 --- clang/lib/Basic/SourceManager.cpp | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/clang/lib/Basic/SourceManager.cpp b/clang/lib/Basic/SourceManager.cpp index eefaacc..603b385 100644 --- a/clang/lib/Basic/SourceManager.cpp +++ b/clang/lib/Basic/SourceManager.cpp @@ -1029,6 +1029,17 @@ unsigned SourceManager::getColumnNumber(FileID FID, unsigned FilePos, return 1; } + // See if we just calculated the line number for this FilePos and can use + // that to lookup the start of the line instead of searching for it. + if (LastLineNoFileIDQuery == FID && + LastLineNoContentCache->SourceLineCache != 0) { + unsigned *SourceLineCache = LastLineNoContentCache->SourceLineCache; + unsigned LineStart = SourceLineCache[LastLineNoResult - 1]; + unsigned LineEnd = SourceLineCache[LastLineNoResult]; + if (FilePos >= LineStart && FilePos < LineEnd) + return FilePos - LineStart + 1; + } + const char *Buf = MemBuf->getBufferStart(); unsigned LineStart = FilePos; while (LineStart && Buf[LineStart-1] != '\n' && Buf[LineStart-1] != '\r') -- 2.7.4