Author: Kevin Cadieux Date: 2022-06-29T10:20:46-07:00 New Revision: a9bef0707db101bb72d000a1f09686d97fb2d35d
URL: https://github.com/llvm/llvm-project/commit/a9bef0707db101bb72d000a1f09686d97fb2d35d DIFF: https://github.com/llvm/llvm-project/commit/a9bef0707db101bb72d000a1f09686d97fb2d35d.diff LOG: [clang-format] Fix incorrect isspace input (NFC) This change fixes a clang-format unit test failure introduced by [D124748](https://reviews.llvm.org/D124748). The `countLeadingWhitespace` function was calling `isspace` with values that could fall outside the valid input range. The valid input range for `isspace` is unsigned 0-255. Values outside this range produce undefined behavior, which on Windows manifests as an assertion being raised in the debug runtime libraries. `countLeadingWhitespace` was calling `isspace` with a signed char that could produce a negative value if the underlying byte's value was 128 or above, which can happen for non-ASCII encodings. The fix is to use `StringRef`'s `bytes_begin` and `bytes_end` iterators to read the values as unsigned chars instead. This bug can be reproduced by building the `check-clang-unit` target with a DEBUG configuration under Windows. This change is already covered by existing unit tests. Reviewed By: MyDeveloperDay Differential Revision: https://reviews.llvm.org/D128786 Added: Modified: clang/lib/Format/FormatTokenLexer.cpp Removed: ################################################################################ diff --git a/clang/lib/Format/FormatTokenLexer.cpp b/clang/lib/Format/FormatTokenLexer.cpp index 88b0d3b1970f7..66f03dcb53a12 100644 --- a/clang/lib/Format/FormatTokenLexer.cpp +++ b/clang/lib/Format/FormatTokenLexer.cpp @@ -864,8 +864,10 @@ static size_t countLeadingWhitespace(StringRef Text) { // Directly using the regex turned out to be slow. With the regex // version formatting all files in this directory took about 1.25 // seconds. This version took about 0.5 seconds. - const char *Cur = Text.begin(); - while (Cur < Text.end()) { + const unsigned char *const Begin = Text.bytes_begin(); + const unsigned char *const End = Text.bytes_end(); + const unsigned char *Cur = Begin; + while (Cur < End) { if (isspace(Cur[0])) { ++Cur; } else if (Cur[0] == '\\' && (Cur[1] == '\n' || Cur[1] == '\r')) { @@ -874,20 +876,20 @@ static size_t countLeadingWhitespace(StringRef Text) { // The source has a null byte at the end. So the end of the entire input // isn't reached yet. Also the lexer doesn't break apart an escaped // newline. - assert(Text.end() - Cur >= 2); + assert(End - Cur >= 2); Cur += 2; } else if (Cur[0] == '?' && Cur[1] == '?' && Cur[2] == '/' && (Cur[3] == '\n' || Cur[3] == '\r')) { // Newlines can also be escaped by a '?' '?' '/' trigraph. By the way, the // characters are quoted individually in this comment because if we write // them together some compilers warn that we have a trigraph in the code. - assert(Text.end() - Cur >= 4); + assert(End - Cur >= 4); Cur += 4; } else { break; } } - return Cur - Text.begin(); + return Cur - Begin; } FormatToken *FormatTokenLexer::getNextToken() { _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
