From d9cad403c0f76cbbcc53efbfeee3d59f9f0b6e09 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. git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@166265 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Basic/SourceManager.cpp | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/lib/Basic/SourceManager.cpp b/lib/Basic/SourceManager.cpp index eefaacc7c3..603b385926 100644 --- a/lib/Basic/SourceManager.cpp +++ b/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') -- 2.50.1