Author: Naveen Seth Hanig Date: 2025-06-25T18:13:00+02:00 New Revision: dd47b845a62cdaf4a1b0aba354cd80a4eabd9570
URL: https://github.com/llvm/llvm-project/commit/dd47b845a62cdaf4a1b0aba354cd80a4eabd9570 DIFF: https://github.com/llvm/llvm-project/commit/dd47b845a62cdaf4a1b0aba354cd80a4eabd9570.diff LOG: [clang-format] Handle Trailing Whitespace After Line Continuation (P2223R2) (#145243) 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. Added: Modified: clang/lib/Format/FormatTokenLexer.cpp clang/unittests/Format/FormatTest.cpp Removed: ################################################################################ diff --git a/clang/lib/Format/FormatTokenLexer.cpp b/clang/lib/Format/FormatTokenLexer.cpp index 4cc4f5f22db0d..06f68ec8b0fc1 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" @@ -1203,16 +1204,22 @@ static size_t countLeadingWhitespace(StringRef Text) { const unsigned char *const End = Text.bytes_end(); const unsigned char *Cur = Begin; while (Cur < End) { - if (isspace(Cur[0])) { + if (isWhitespace(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 backslash followed by optional horizontal whitespaces (P22232R2) and + // then a newline always escapes the newline. // 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 auto *Lookahead = Cur + 1; + while (isHorizontalWhitespace(*Lookahead)) + ++Lookahead; + // No line splice found; the backslash is a token. + if (!isVerticalWhitespace(*Lookahead)) + break; + // Splice found, consume it. + Cur = Lookahead + 1; } 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 +1302,18 @@ 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/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp index c0633ba3c29b3..a05bf8305716b 100644 --- a/clang/unittests/Format/FormatTest.cpp +++ b/clang/unittests/Format/FormatTest.cpp @@ -25768,6 +25768,21 @@ TEST_F(FormatTest, OperatorPassedAsAFunctionPtr) { verifyFormat("foo(operator, , -42);", Style); } +TEST_F(FormatTest, LineSpliceWithTrailingWhitespace) { + auto Style = getLLVMStyle(); + Style.AlignEscapedNewlines = FormatStyle::ENAS_DontAlign; + Style.UseTab = FormatStyle::UT_Never; + + verifyFormat("int i;", " \\ \n" + " int i;"); + verifyFormat("#define FOO(args) \\\n" + " struct a {};", + "#define FOO( args ) \\ \n" + "struct a{\\\t\t\t\n" + " };", + Style); +} + TEST_F(FormatTest, WhitespaceSensitiveMacros) { FormatStyle Style = getLLVMStyle(); Style.WhitespaceSensitiveMacros.push_back("FOO"); _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
