[clang] 449cdfa - Suppress pedantic diagnostic for a file not ending in EOL (#131794)
via cfe-commits
cfe-commits at lists.llvm.org
Wed Mar 19 04:49:20 PDT 2025
Author: Aaron Ballman
Date: 2025-03-19T07:49:16-04:00
New Revision: 449cdfacc07bd365d49a637196ce8f8067cf845c
URL: https://github.com/llvm/llvm-project/commit/449cdfacc07bd365d49a637196ce8f8067cf845c
DIFF: https://github.com/llvm/llvm-project/commit/449cdfacc07bd365d49a637196ce8f8067cf845c.diff
LOG: Suppress pedantic diagnostic for a file not ending in EOL (#131794)
WG14 added N3411 to the list of papers which apply to older versions of
C in C2y, and WG21 adopted CWG787 as a Defect Report in C++11. So we no
longer should be issuing a pedantic diagnostic about a file which does
not end with a newline character.
We do, however, continue to support -Wnewline-eof as an opt-in
diagnostic.
Added:
clang/test/CXX/drs/cwg787.cpp
Modified:
clang-tools-extra/clangd/Preamble.cpp
clang/docs/ReleaseNotes.rst
clang/include/clang/Basic/DiagnosticLexKinds.td
clang/lib/Lex/Lexer.cpp
clang/test/C/C2y/n3411.c
clang/test/Lexer/newline-eof.c
Removed:
clang/test/Lexer/newline-eof-c++98-compat.cpp
################################################################################
diff --git a/clang-tools-extra/clangd/Preamble.cpp b/clang-tools-extra/clangd/Preamble.cpp
index b634981bb46bd..6fab3e2191426 100644
--- a/clang-tools-extra/clangd/Preamble.cpp
+++ b/clang-tools-extra/clangd/Preamble.cpp
@@ -627,10 +627,8 @@ buildPreamble(PathRef FileName, CompilerInvocation CI,
return DiagnosticsEngine::Ignored;
switch (Info.getID()) {
case diag::warn_no_newline_eof:
- case diag::warn_cxx98_compat_no_newline_eof:
- case diag::ext_no_newline_eof:
// If the preamble doesn't span the whole file, drop the no newline at
- // eof warnings.
+ // eof warning.
return Bounds.Size != ContentsBuffer->getBufferSize()
? DiagnosticsEngine::Level::Ignored
: DiagLevel;
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 867ce60207b9d..075bcc64b1c59 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -130,8 +130,10 @@ C2y Feature Support
that ``_Generic`` selection associations may now have ``void`` type, but it
also removes UB with code like ``(void)(void)1;``.
- Implemented `WG14 N3411 <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3411.pdf>`_
- which allows a source file to not end with a newline character. This is still
- reported as a conforming extension in earlier language modes.
+ which allows a source file to not end with a newline character. Note,
+ ``-pedantic`` will no longer diagnose this in either C or C++ modes. This
+ feature was adopted as applying to obsolete versions of C in WG14 and as a
+ defect report in WG21 (CWG787).
- Implemented `WG14 N3353 <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3353.htm>_`
which adds the new ``0o`` and ``0O`` ocal literal prefixes and deprecates
octal literals other than ``0`` which do not start with the new prefix. This
diff --git a/clang/include/clang/Basic/DiagnosticLexKinds.td b/clang/include/clang/Basic/DiagnosticLexKinds.td
index bdb7e9350b5f7..912b8bd46e194 100644
--- a/clang/include/clang/Basic/DiagnosticLexKinds.td
+++ b/clang/include/clang/Basic/DiagnosticLexKinds.td
@@ -52,15 +52,9 @@ def ext_multi_line_line_comment : Extension<"multi-line // comment">,
def ext_line_comment : Extension<
"// comments are not allowed in this language">,
InGroup<Comment>;
-def ext_no_newline_eof : Extension<"no newline at end of file">,
- InGroup<NewlineEOF>;
def warn_no_newline_eof : Warning<"no newline at end of file">,
InGroup<NewlineEOF>, DefaultIgnore;
-def warn_cxx98_compat_no_newline_eof : Warning<
- "C++98 requires newline at end of file">,
- InGroup<CXX98CompatPedantic>, DefaultIgnore;
-
def ext_dollar_in_identifier : Extension<"'$' in identifier">,
InGroup<DiagGroup<"dollar-in-identifier-extension">>;
def ext_charize_microsoft : Extension<
diff --git a/clang/lib/Lex/Lexer.cpp b/clang/lib/Lex/Lexer.cpp
index 96d5d4f440768..3128627490e28 100644
--- a/clang/lib/Lex/Lexer.cpp
+++ b/clang/lib/Lex/Lexer.cpp
@@ -3187,28 +3187,12 @@ bool Lexer::LexEndOfFile(Token &Result, const char *CurPtr) {
ConditionalStack.pop_back();
}
- // C99 5.1.1.2p2: If the file is non-empty and didn't end in a newline, issue
- // a pedwarn.
- if (CurPtr != BufferStart && (CurPtr[-1] != '\n' && CurPtr[-1] != '\r')) {
- DiagnosticsEngine &Diags = PP->getDiagnostics();
- SourceLocation EndLoc = getSourceLocation(BufferEnd);
- unsigned DiagID = diag::warn_no_newline_eof;
-
- if (LangOpts.CPlusPlus11) {
- // C++11 [lex.phases] 2.2 p2
- // Prefer the C++98 pedantic compatibility warning over the generic,
- // non-extension, user-requested "missing newline at EOF" warning.
- if (!Diags.isIgnored(diag::warn_cxx98_compat_no_newline_eof, EndLoc))
- DiagID = diag::warn_cxx98_compat_no_newline_eof;
- } else {
- // This is conforming in C2y, but is an extension in earlier language
- // modes.
- if (!LangOpts.C2y)
- DiagID = diag::ext_no_newline_eof;
- }
-
- Diag(BufferEnd, DiagID) << FixItHint::CreateInsertion(EndLoc, "\n");
- }
+ // Before C++11 and C2y, a file not ending with a newline was UB. Both
+ // standards changed this behavior (as a DR or equivalent), but we still have
+ // an opt-in diagnostic to warn about it.
+ if (CurPtr != BufferStart && (CurPtr[-1] != '\n' && CurPtr[-1] != '\r'))
+ Diag(BufferEnd, diag::warn_no_newline_eof)
+ << FixItHint::CreateInsertion(getSourceLocation(BufferEnd), "\n");
BufferPtr = CurPtr;
diff --git a/clang/test/C/C2y/n3411.c b/clang/test/C/C2y/n3411.c
index 934a7c70fa67e..0fea769e30460 100644
--- a/clang/test/C/C2y/n3411.c
+++ b/clang/test/C/C2y/n3411.c
@@ -1,7 +1,8 @@
// RUN: %clang_cc1 -verify=good -std=c2y -Wall -pedantic %s
// RUN: %clang_cc1 -verify -Wnewline-eof -std=c2y -Wall -pedantic %s
-// RUN: %clang_cc1 -verify -std=c23 -Wall -pedantic %s
+// RUN: %clang_cc1 -verify=good -std=c23 -Wall -pedantic %s
// RUN: %clang_cc1 -verify=good -std=c23 %s
+// RUN: %clang_cc1 -verify -Wnewline-eof -std=c23 %s
/* WG14 N3411: Yes
* Slay Some Earthly Demons XII
diff --git a/clang/test/CXX/drs/cwg787.cpp b/clang/test/CXX/drs/cwg787.cpp
new file mode 100644
index 0000000000000..4b5aeb6487a00
--- /dev/null
+++ b/clang/test/CXX/drs/cwg787.cpp
@@ -0,0 +1,13 @@
+// RUN: %clang_cc1 -triple %itanium_abi_triple -std=c++98 %s -verify -fexceptions -fcxx-exceptions -pedantic-errors
+// RUN: %clang_cc1 -triple %itanium_abi_triple -std=c++11 %s -verify -fexceptions -fcxx-exceptions -pedantic-errors
+// RUN: %clang_cc1 -triple %itanium_abi_triple -std=c++14 %s -verify -fexceptions -fcxx-exceptions -pedantic-errors
+// RUN: %clang_cc1 -triple %itanium_abi_triple -std=c++17 %s -verify -fexceptions -fcxx-exceptions -pedantic-errors
+// RUN: %clang_cc1 -triple %itanium_abi_triple -std=c++20 %s -verify -fexceptions -fcxx-exceptions -pedantic-errors
+// RUN: %clang_cc1 -triple %itanium_abi_triple -std=c++23 %s -verify -fexceptions -fcxx-exceptions -pedantic-errors
+// RUN: %clang_cc1 -triple %itanium_abi_triple -std=c++2c %s -verify -fexceptions -fcxx-exceptions -pedantic-errors
+// expected-no-diagnostics
+
+// This file intentionally does not end with a newline. CWG787 made this
+// well-defined behavior.
+
+// cwg787: 21
\ No newline at end of file
diff --git a/clang/test/Lexer/newline-eof-c++98-compat.cpp b/clang/test/Lexer/newline-eof-c++98-compat.cpp
deleted file mode 100644
index 9af0b889537b8..0000000000000
--- a/clang/test/Lexer/newline-eof-c++98-compat.cpp
+++ /dev/null
@@ -1,5 +0,0 @@
-// RUN: %clang_cc1 -fsyntax-only -Wc++98-compat-pedantic -std=c++11 -verify %s
-// RUN: %clang_cc1 -fsyntax-only -Wc++98-compat-pedantic -Wnewline-eof -std=c++11 -verify %s
-
-// The following line isn't terminated, don't fix it.
-void foo() {} // expected-warning{{C++98 requires newline at end of file}}
\ No newline at end of file
diff --git a/clang/test/Lexer/newline-eof.c b/clang/test/Lexer/newline-eof.c
index 9f5033384e16f..22245ac357efc 100644
--- a/clang/test/Lexer/newline-eof.c
+++ b/clang/test/Lexer/newline-eof.c
@@ -1,11 +1,16 @@
-// RUN: %clang_cc1 -fsyntax-only -Wnewline-eof -verify %s
-// RUN: %clang_cc1 -fsyntax-only -pedantic -verify %s
-// RUN: %clang_cc1 -fsyntax-only -x c++ -std=c++03 -pedantic -verify %s
-// RUN: %clang_cc1 -fsyntax-only -Wnewline-eof %s 2>&1 | FileCheck %s
+// Allowing a file to end without a newline was adopted as a Defect Report in
+// WG21 (CWG787) and in WG14 (added to the list of changes which apply to
+// earlier revisions of C in C2y). So it should not issue a pedantic diagnostic
+// in any language mode.
-// In C++11 mode, this is allowed, so don't warn in pedantic mode.
+// RUN: %clang_cc1 -fsyntax-only -Wnewline-eof -verify %s
+// RUN: %clang_cc1 -fsyntax-only -pedantic -verify=good %s
+// RUN: %clang_cc1 -fsyntax-only -std=c89 -pedantic -Wno-comment -verify=good %s
+// RUN: %clang_cc1 -fsyntax-only -x c++ -std=c++03 -pedantic -verify=good %s
// RUN: %clang_cc1 -fsyntax-only -x c++ -std=c++11 -Wnewline-eof -verify %s
// RUN: %clang_cc1 -fsyntax-only -x c++ -std=c++11 -Werror -pedantic %s
+// RUN: %clang_cc1 -fsyntax-only -Wnewline-eof %s 2>&1 | FileCheck %s
+// good-no-diagnostics
// Make sure the diagnostic shows up properly at the end of the last line.
// CHECK: newline-eof.c:[[@LINE+3]]:67
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