https://github.com/chenmiaoming created https://github.com/llvm/llvm-project/pull/215082
CXXNewExpr::getArraySize() returns std::nullopt even when isArray() is true, e.g. when there is no array size expression, as in 'new int[]()'. The hasArraySize matcher dereferenced the optional unconditionally, triggering undefined behavior (an assertion failure in assert-enabled builds). Check the optional for engagement before matching. Since getArraySize() already returns std::nullopt when isArray() is false, the redundant isArray() check can be dropped. Add a clang-tidy regression test that runs clang-tidy on a translation unit containing 'new int[]()', which emits a compiler diagnostic but must not crash the tool, and document the fix in the release notes. Fixes #214281 >From 3ca8576afc8dc0a55000f211666c564f5073f9df Mon Sep 17 00:00:00 2001 From: MiaoMing Chen <[email protected]> Date: Sun, 9 Aug 2026 14:14:02 +0800 Subject: [PATCH] [clang][ASTMatchers] Fix `hasArraySize` crash without a size expression CXXNewExpr::getArraySize() returns std::nullopt even when isArray() is true, e.g. when there is no array size expression, as in 'new int[]()'. The hasArraySize matcher dereferenced the optional unconditionally, triggering undefined behavior (an assertion failure in assert-enabled builds). Check the optional for engagement before matching. Since getArraySize() already returns std::nullopt when isArray() is false, the redundant isArray() check can be dropped. Add a clang-tidy regression test that runs clang-tidy on a translation unit containing 'new int[]()', which emits a compiler diagnostic but must not crash the tool, and document the fix in the release notes. Fixes #214281 --- clang-tools-extra/docs/ReleaseNotes.md | 4 ++++ .../misplaced-operator-in-strlen-in-alloc-no-crash.cpp | 4 ++++ clang/include/clang/ASTMatchers/ASTMatchers.h | 4 ++-- 3 files changed, 10 insertions(+), 2 deletions(-) create mode 100644 clang-tools-extra/test/clang-tidy/checkers/bugprone/misplaced-operator-in-strlen-in-alloc-no-crash.cpp diff --git a/clang-tools-extra/docs/ReleaseNotes.md b/clang-tools-extra/docs/ReleaseNotes.md index 5ded07934d906..4fc25558ae42a 100644 --- a/clang-tools-extra/docs/ReleaseNotes.md +++ b/clang-tools-extra/docs/ReleaseNotes.md @@ -102,6 +102,10 @@ infrastructure are described first, followed by tool-specific sections. #### Changes in existing checks +- Fixed a crash in {doc}`bugprone-misplaced-operator-in-strlen-in-alloc + <clang-tidy/checks/bugprone/misplaced-operator-in-strlen-in-alloc>` when + checking an array new expression without a size expression. + - Fixed a crash in {doc}`bugprone-std-namespace-modification <clang-tidy/checks/bugprone/std-namespace-modification>` when checking lambda closure types used as template arguments. diff --git a/clang-tools-extra/test/clang-tidy/checkers/bugprone/misplaced-operator-in-strlen-in-alloc-no-crash.cpp b/clang-tools-extra/test/clang-tidy/checkers/bugprone/misplaced-operator-in-strlen-in-alloc-no-crash.cpp new file mode 100644 index 0000000000000..c7b60100e0763 --- /dev/null +++ b/clang-tools-extra/test/clang-tidy/checkers/bugprone/misplaced-operator-in-strlen-in-alloc-no-crash.cpp @@ -0,0 +1,4 @@ +// RUN: %check_clang_tidy -expect-clang-tidy-error %s bugprone-misplaced-operator-in-strlen-in-alloc %t + +void *f() { return new int[](); } +// CHECK-MESSAGES: :[[@LINE-1]]:24: error: cannot determine allocated array size from initializer [clang-diagnostic-error] diff --git a/clang/include/clang/ASTMatchers/ASTMatchers.h b/clang/include/clang/ASTMatchers/ASTMatchers.h index 02d52b51a45c9..c168937d3641c 100644 --- a/clang/include/clang/ASTMatchers/ASTMatchers.h +++ b/clang/include/clang/ASTMatchers/ASTMatchers.h @@ -8652,8 +8652,8 @@ AST_MATCHER_P(CXXNewExpr, hasAnyPlacementArg, internal::Matcher<Expr>, /// cxxNewExpr(hasArraySize(integerLiteral(equals(10)))) /// matches the expression 'new MyClass[10]'. AST_MATCHER_P(CXXNewExpr, hasArraySize, internal::Matcher<Expr>, InnerMatcher) { - return Node.isArray() && *Node.getArraySize() && - InnerMatcher.matches(**Node.getArraySize(), Finder, Builder); + const auto ArraySize = Node.getArraySize(); + return ArraySize && InnerMatcher.matches(**ArraySize, Finder, Builder); } /// Matches a class declaration that is defined. _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
