llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-clang @llvm/pr-subscribers-clang-format Author: Naveen Seth Hanig (naveen-seth) <details> <summary>Changes</summary> Fixes #<!-- -->145226. Implement [P2223R2](https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2021/p2223r2.pdf) in clang-format to correctly handle cases where a backslash '\\' is followed by trailing whitespace before the newline. Previously, `clang-format` failed to properly detect and handle such cases, leading to misformatted code. With this, `clang-format` matches the behavior already implemented in Clang's lexer and `DependencyDirectivesScanner.cpp`, which allow trailing whitespace after a line continuation in any C++ standard. --- Full diff: https://github.com/llvm/llvm-project/pull/145243.diff 3 Files Affected: - (modified) clang/docs/ReleaseNotes.rst (+3) - (modified) clang/lib/Format/FormatTokenLexer.cpp (+23-8) - (added) clang/test/Format/splice-trailing-whitespace-p2223r2.cpp (+14) ``````````diff diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index 96477ef6ddc9a..7c8e231655e86 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -1025,6 +1025,9 @@ clang-format ``enum`` enumerator lists. - Add ``OneLineFormatOffRegex`` option for turning formatting off for one line. - Add ``SpaceAfterOperatorKeyword`` option. +- Support trailing whitespace in line splicing. + (P2223R2 <https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2021/p2223r2.pdf>_, #GH145226) + clang-refactor -------------- diff --git a/clang/lib/Format/FormatTokenLexer.cpp b/clang/lib/Format/FormatTokenLexer.cpp index 4cc4f5f22db0d..bcc8e6ffd91ab 100644 --- a/clang/lib/Format/FormatTokenLexer.cpp +++ b/clang/lib/Format/FormatTokenLexer.cpp @@ -14,6 +14,7 @@ #include "FormatTokenLexer.h" #include "FormatToken.h" +#include "clang/Basic/CharInfo.h" #include "clang/Basic/SourceLocation.h" #include "clang/Basic/SourceManager.h" #include "clang/Format/Format.h" @@ -1205,14 +1206,23 @@ static size_t countLeadingWhitespace(StringRef Text) { while (Cur < End) { if (isspace(Cur[0])) { ++Cur; - } else if (Cur[0] == '\\' && (Cur[1] == '\n' || Cur[1] == '\r')) { - // A '\' followed by a newline always escapes the newline, regardless - // of whether there is another '\' before it. + } else if (Cur[0] == '\\') { + // A '\' followed by a optional horizontal whitespace (P22232R2) and then + // newline always escapes the newline, regardless of whether there is + // another '\' before it. // 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(End - Cur >= 2); - Cur += 2; + const unsigned char *Lookahead = Cur + 1; + while (isHorizontalWhitespace(*Lookahead)) + ++Lookahead; + if (*Lookahead == '\n' || *Lookahead == '\r') { + // Splice found, consume it. + Cur = Lookahead + 1; + continue; + } + // No line splice found; the '\' is a token. + break; } 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 @@ -1295,13 +1305,18 @@ FormatToken *FormatTokenLexer::getNextToken() { case '/': // The text was entirely whitespace when this loop was entered. Thus // this has to be an escape sequence. - assert(Text.substr(i, 2) == "\\\r" || Text.substr(i, 2) == "\\\n" || - Text.substr(i, 4) == "\?\?/\r" || + assert(Text.substr(i, 4) == "\?\?/\r" || Text.substr(i, 4) == "\?\?/\n" || (i >= 1 && (Text.substr(i - 1, 4) == "\?\?/\r" || Text.substr(i - 1, 4) == "\?\?/\n")) || (i >= 2 && (Text.substr(i - 2, 4) == "\?\?/\r" || - Text.substr(i - 2, 4) == "\?\?/\n"))); + Text.substr(i - 2, 4) == "\?\?/\n")) || + (Text[i] == '\\' && [&]() -> bool { + size_t j = i + 1; + while (j < Text.size() && isHorizontalWhitespace(Text[j])) + ++j; + return j < Text.size() && (Text[j] == '\n' || Text[j] == '\r'); + }())); InEscape = true; break; default: diff --git a/clang/test/Format/splice-trailing-whitespace-p2223r2.cpp b/clang/test/Format/splice-trailing-whitespace-p2223r2.cpp new file mode 100644 index 0000000000000..3cc08cc631965 --- /dev/null +++ b/clang/test/Format/splice-trailing-whitespace-p2223r2.cpp @@ -0,0 +1,14 @@ +// RUN: grep -Ev "// *[A-Z-]+:" %s \ +// RUN: | clang-format -style='{BasedOnStyle: LLVM, AlignEscapedNewlines: DontAlign}' \ +// RUN: | FileCheck -strict-whitespace %s + +// CHECK: {{^#define TAG\(\.\.\.\) \\}} +// CHECK: {{^ struct a \{\};}} +// There is whitespace following v this backslash! +#define TAG(...) struct a { \ + }; + +// CHECK: {{^int i;}} +// The comment below eats its following line because of the line splice. +// I also have trailing whitespace. Nom nom nom \ +int i; `````````` </details> https://github.com/llvm/llvm-project/pull/145243 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
