Next step toward making string diagnostics correct: handle
escapes in the string for subtoken positioning. This gives
us working examples like:
t.m:5:16: warning: field width should have type 'int', but argument has type 'unsigned int'
printf("\n\n%*d", (unsigned) 1, 1);
^ ~~~~~~~~~~~~
where before the caret pointed two spaces to the left.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@64940 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Lex/LiteralSupport.cpp b/lib/Lex/LiteralSupport.cpp
index 93b653a..9815f9b 100644
--- a/lib/Lex/LiteralSupport.cpp
+++ b/lib/Lex/LiteralSupport.cpp
@@ -798,3 +798,49 @@
return;
}
}
+
+
+/// getOffsetOfStringByte - This function returns the offset of the
+/// specified byte of the string data represented by Token. This handles
+/// advancing over escape sequences in the string.
+unsigned StringLiteralParser::getOffsetOfStringByte(const Token &Tok,
+ unsigned ByteNo,
+ Preprocessor &PP) {
+ // Get the spelling of the token.
+ llvm::SmallString<16> SpellingBuffer;
+ SpellingBuffer.resize(Tok.getLength());
+
+ const char *SpellingPtr = &SpellingBuffer[0];
+ unsigned TokLen = PP.getSpelling(Tok, SpellingPtr);
+
+ assert(SpellingPtr[0] != 'L' && "Doesn't handle wide strings yet");
+
+
+ const char *SpellingStart = SpellingPtr;
+ const char *SpellingEnd = SpellingPtr+TokLen;
+
+ // Skip over the leading quote.
+ assert(SpellingPtr[0] == '"' && "Should be a string literal!");
+ ++SpellingPtr;
+
+ // Skip over bytes until we find the offset we're looking for.
+ while (ByteNo) {
+ assert(SpellingPtr < SpellingEnd && "Didn't find byte offset!");
+
+ // Step over non-escapes simply.
+ if (*SpellingPtr != '\\') {
+ ++SpellingPtr;
+ --ByteNo;
+ continue;
+ }
+
+ // Otherwise, this is an escape character. Advance over it.
+ bool HadError = false;
+ ProcessCharEscape(SpellingPtr, SpellingEnd, HadError,
+ Tok.getLocation(), false, PP);
+ assert(!HadError && "This method isn't valid on erroneous strings");
+ --ByteNo;
+ }
+
+ return SpellingPtr-SpellingStart;
+}