Add a new Preprocessor::AdvanceToTokenCharacter method which, given a sloc
specifying the start of a token and a logical (phase 3) character number,
returns a sloc representing the input character corresponding to it.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@39905 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/Lex/Preprocessor.cpp b/Lex/Preprocessor.cpp
index 8376b9f..9301793 100644
--- a/Lex/Preprocessor.cpp
+++ b/Lex/Preprocessor.cpp
@@ -36,6 +36,7 @@
#include "clang/Basic/SourceManager.h"
#include "clang/Basic/TargetInfo.h"
#include "llvm/ADT/SmallVector.h"
+#include "llvm/Support/MemoryBuffer.h"
#include <iostream>
using namespace clang;
@@ -253,6 +254,42 @@
}
+/// AdvanceToTokenCharacter - Given a location that specifies the start of a
+/// token, return a new location that specifies a character within the token.
+SourceLocation Preprocessor::AdvanceToTokenCharacter(SourceLocation TokStart,
+ unsigned CharNo) {
+ // If they request the first char of the token, we're trivially done.
+ if (CharNo == 0) return TokStart;
+
+ // Figure out how many physical characters away the specified logical
+ // character is. This needs to take into consideration newlines and
+ // trigraphs.
+ const char *TokStartPtr = SourceMgr.getCharacterData(TokStart);
+ const char *TokPtr = TokStartPtr;
+
+ // The usual case is that tokens don't contain anything interesting. Skip
+ // over the uninteresting characters. If a token only consists of simple
+ // chars, this method is extremely fast.
+ while (CharNo && Lexer::isObviouslySimpleCharacter(*TokPtr))
+ ++TokPtr, --CharNo;
+
+ // If we have a character that may be a trigraph or escaped newline, create a
+ // lexer to parse it correctly.
+ unsigned FileID = TokStart.getFileID();
+ const llvm::MemoryBuffer *SrcBuf = SourceMgr.getBuffer(FileID);
+ if (CharNo != 0) {
+ // Create a lexer starting at this token position.
+ Lexer TheLexer(SrcBuf, FileID, *this, TokPtr);
+ LexerToken Tok;
+ // Skip over characters the remaining characters.
+ for (; CharNo; --CharNo)
+ TheLexer.getAndAdvanceChar(TokPtr, Tok);
+ }
+ return SourceLocation(FileID, TokPtr-SrcBuf->getBufferStart());
+}
+
+
+
//===----------------------------------------------------------------------===//
// Source File Location Methods.
//===----------------------------------------------------------------------===//