https://github.com/akash-manna-sky updated https://github.com/llvm/llvm-project/pull/226691
>From 1a9aaafd8e29101e5db9fadac9527f09b4d56928 Mon Sep 17 00:00:00 2001 From: Akash Manna <[email protected]> Date: Sat, 26 Sep 2026 18:25:33 +0530 Subject: [PATCH] [clang][OpenMP] Fix crash on global reference in target region inside a namespace-scope lambda SemaOpenMP::isOpenMPCapturedDecl figures out whether a global must be captured for a target region by walking the function scope stack down to the innermost OpenMP captured region, and it stops as soon as it meets an ordinary function scope. When a directive is finished, the capture initializers of its outermost region are built after every region has been popped, while the directive is still on the DSA stack. Inside a function that walk simply ends at the function's scope. A lambda or block at namespace scope has no scope underneath it at all, so the walk ran off the end of the stack and tripped the assertion. The self-referential declaration in the report is incidental: plain `int &r = x; auto l = [] { #pragma omp target r = 1; };` crashes the same way, and so do lambdas in default arguments and in variable template instantiations. Running out of scopes now means the same thing as reaching a function scope: the variable is not captured from the current scope, so the walk returns null. That is exactly what the same lambda already gets when it sits inside a function, and it matches what the neighbouring walk for the CheckScopeInfo case already does when it finds no OpenMP region. Fixes #223397 --- clang/docs/ReleaseNotes.md | 1 + clang/lib/Sema/SemaOpenMP.cpp | 6 +- ...rget_global_ref_namespace_scope_lambda.cpp | 55 +++++++++++++++++++ 3 files changed, 61 insertions(+), 1 deletion(-) create mode 100644 clang/test/OpenMP/target_global_ref_namespace_scope_lambda.cpp diff --git a/clang/docs/ReleaseNotes.md b/clang/docs/ReleaseNotes.md index f4a34a37aff52e..4164ab1da17f2c 100644 --- a/clang/docs/ReleaseNotes.md +++ b/clang/docs/ReleaseNotes.md @@ -544,6 +544,7 @@ features cannot lower the translation-unit ABI level; - Fixed a crash when declaring a member template within a local class inside an OpenMP region. (#GH216052) - Fixed a bug where repeated #imports of modular headers in non-modular compilation were translated to #pragma clang module import. (#GH216924) - Fixed an assertion when `#pragma omp declare simd` or `#pragma omp declare variant` is followed by another OpenMP declarative directive containing a qualified identifier. (#GH217204) +- Fixed a crash when a reference variable with static storage duration, such as a global reference, was used in an OpenMP `target` region inside a lambda or block at namespace scope. (#GH223397) - Fixed a crash when an `asm` label names the register for a global variable of incomplete type. (#GH219746) - Fixed an ICE hat occurred when using `__imag int/float` as lvalue in assignment. (#GH119498) - Fixed an assertion failure in `-Wsign-compare` when a negated or complemented vector of unsigned integers was compared against a signed constant. (#GH203575) diff --git a/clang/lib/Sema/SemaOpenMP.cpp b/clang/lib/Sema/SemaOpenMP.cpp index 2e4d9f2f82f0b7..6cbfe113902a3e 100644 --- a/clang/lib/Sema/SemaOpenMP.cpp +++ b/clang/lib/Sema/SemaOpenMP.cpp @@ -2473,7 +2473,11 @@ VarDecl *SemaOpenMP::isOpenMPCapturedDecl(ValueDecl *D, bool CheckScopeInfo, break; } } - assert(CSI && "Failed to find CapturedRegionScopeInfo"); + // A lambda or block at namespace scope has no enclosing function scope, + // so the walk can run out of scopes once all captured regions of the + // directive have been left. + if (!CSI) + return nullptr; SmallVector<OpenMPDirectiveKind, 4> Regions; getOpenMPCaptureRegions(Regions, DSAStack->getDirective(CSI->OpenMPLevel)); diff --git a/clang/test/OpenMP/target_global_ref_namespace_scope_lambda.cpp b/clang/test/OpenMP/target_global_ref_namespace_scope_lambda.cpp new file mode 100644 index 00000000000000..32a7e6dfd74e4b --- /dev/null +++ b/clang/test/OpenMP/target_global_ref_namespace_scope_lambda.cpp @@ -0,0 +1,55 @@ +// RUN: %clang_cc1 -verify -fopenmp -fblocks -fsyntax-only %s +// RUN: %clang_cc1 -verify -fopenmp-simd -fblocks -fsyntax-only %s + +// A reference without local storage used in a target region inside a lambda or +// block at namespace scope used to assert in SemaOpenMP::isOpenMPCapturedDecl. + +int x; +int &ref = x; + +auto lambda = []() { +#pragma omp target + ref = 42; +}; + +auto nested_lambda = []() { + return []() { +#pragma omp target + ref = 42; + }; +}; + +auto combined_directive = []() { +#pragma omp target teams + ref = 42; +}; + +auto static_local = []() { + static int &local_ref = x; +#pragma omp target + local_ref = 42; +}; + +void (^block)() = ^{ +#pragma omp target + ref = 42; +}; + +void default_argument(int = []() { +#pragma omp target + ref = 42; + return 0; +}()); + +template <int N> int variable_template = []() { +#pragma omp target + ref = N; + return 0; +}(); +int instantiation = variable_template<1>; + +// Reproducer from GH223397. +int &foo = []() { // expected-error {{non-const lvalue reference to type 'int' cannot bind to a temporary of type '(lambda at}} +#pragma omp target + foo(42); // expected-error {{called object type 'int' is not a function or function pointer}} +}; _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
