[clang][lex] Fix lexing malformed pragma within include directive

[sweiglbosker]

fixes: #138094
this patch fixes a crash triggered by lexing past eof when emitting a diagnostic for a malformed _Pragma directive within an include directive.
Fixed by by preventing the lexer from eating a tok::eod.

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[llvmbot]

@llvm/pr-subscribers-clang

Author: Stefan (sweiglbosker)

Changes

fixes: #138094
this patch fixes a crash triggered by Lexing past eof when emitting a diagnostic for a malformed _Pragma directive within an include directive.
Fixed by by preventing the lexer from eating a tok::eod.

---

Full diff: https://github.com/llvm/llvm-project/pull/138165.diff

1 Files Affected:

• (modified) clang/lib/Lex/Pragma.cpp (+3-2)

diff --git a/clang/lib/Lex/Pragma.cpp b/clang/lib/Lex/Pragma.cpp
index 5b6a29bdad910..607e7b6a7dceb 100644
--- a/clang/lib/Lex/Pragma.cpp
+++ b/clang/lib/Lex/Pragma.cpp
@@ -220,11 +220,12 @@ void Preprocessor::Handle_Pragma(Token &Tok) {
   if (!tok::isStringLiteral(Tok.getKind())) {
     Diag(PragmaLoc, diag::err__Pragma_malformed);
     // Skip bad tokens, and the ')', if present.
-    if (Tok.isNot(tok::r_paren) && Tok.isNot(tok::eof))
+    if (Tok.isNot(tok::r_paren) && Tok.isNot(tok::eof) && Tok.isNot(tok::eod))
       Lex(Tok);
     while (Tok.isNot(tok::r_paren) &&
            !Tok.isAtStartOfLine() &&
-           Tok.isNot(tok::eof))
+           Tok.isNot(tok::eof) &&
+           Tok.isNot(tok::eod))
       Lex(Tok);
     if (Tok.is(tok::r_paren))
       Lex(Tok);

[github-actions]

⚠️ C/C++ code formatter, clang-format found issues in your code. ⚠️

You can test this locally with the following command:

git-clang-format --diff HEAD~1 HEAD --extensions cpp -- clang/lib/Lex/Pragma.cpp

View the diff from clang-format here.

diff --git a/clang/lib/Lex/Pragma.cpp b/clang/lib/Lex/Pragma.cpp
index 607e7b6a7..ea7eda0d0 100644
--- a/clang/lib/Lex/Pragma.cpp
+++ b/clang/lib/Lex/Pragma.cpp
@@ -222,10 +222,8 @@ void Preprocessor::Handle_Pragma(Token &Tok) {
     // Skip bad tokens, and the ')', if present.
     if (Tok.isNot(tok::r_paren) && Tok.isNot(tok::eof) && Tok.isNot(tok::eod))
       Lex(Tok);
-    while (Tok.isNot(tok::r_paren) &&
-           !Tok.isAtStartOfLine() &&
-           Tok.isNot(tok::eof) &&
-           Tok.isNot(tok::eod))
+    while (Tok.isNot(tok::r_paren) && !Tok.isAtStartOfLine() &&
+           Tok.isNot(tok::eof) && Tok.isNot(tok::eod))
       Lex(Tok);
     if (Tok.is(tok::r_paren))
       Lex(Tok);

[shafik]

Thank you for the fix, this needs a test and release note.

Release notes for clang are in clang/docs/ReleaseNotes.rst.

I am not sure what the right file for testing is though @AaronBallman

[AaronBallman]

Thanks for the fix! Given the nature of the issue, I would probably introduce a new test file rather than modify an existing one. But I think it should live in clang/test/Preprocessor.

[AaronBallman]

Generally LGTM, though a few suggested changes.

[sweiglbosker]

Done

[github-actions]

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