Author: serge-sans-paille Date: 2022-07-10T08:40:03+02:00 New Revision: da6a14b91ad999327b41a9040577273591e4ad1d
URL: https://github.com/llvm/llvm-project/commit/da6a14b91ad999327b41a9040577273591e4ad1d DIFF: https://github.com/llvm/llvm-project/commit/da6a14b91ad999327b41a9040577273591e4ad1d.diff LOG: [clang] Enforce instantiation of constexpr template functions during non-constexpr evaluation Otherwise these functions are not instantiated and we end up with an undefined symbol. Fix #55560 Differential Revision: https://reviews.llvm.org/D128119 Added: clang/test/CodeGenCXX/constexpr-late-instantiation.cpp clang/test/SemaCXX/constexpr-late-instantiation.cpp Modified: clang/docs/ReleaseNotes.rst clang/lib/Sema/SemaTemplateInstantiateDecl.cpp Removed: ################################################################################ diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index 5dae6205efa05..27ba4f1c6a422 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -181,6 +181,8 @@ Bug Fixes emitted as a dynamic initializer. Previously the variable would incorrectly be zero-initialized. In contexts where a dynamic initializer is not allowed this is now diagnosed as an error. +- Clang now correctly emits symbols for implicitly instantiated constexpr + template function. Fixes `Issue 55560 <https://github.com/llvm/llvm-project/issues/55560>`_. Improvements to Clang's diagnostics ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ diff --git a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp index d7558017948a2..10dc04b7e09a4 100644 --- a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp +++ b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp @@ -4840,7 +4840,8 @@ void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation, /*Complain*/DefinitionRequired)) { if (DefinitionRequired) Function->setInvalidDecl(); - else if (TSK == TSK_ExplicitInstantiationDefinition) { + else if (TSK == TSK_ExplicitInstantiationDefinition || + (Function->isConstexpr() && !Recursive)) { // Try again at the end of the translation unit (at which point a // definition will be required). assert(!Recursive); @@ -4855,7 +4856,7 @@ void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation, Diag(PatternDecl->getLocation(), diag::note_forward_template_decl); if (getLangOpts().CPlusPlus11) Diag(PointOfInstantiation, diag::note_inst_declaration_hint) - << Function; + << Function; } } diff --git a/clang/test/CodeGenCXX/constexpr-late-instantiation.cpp b/clang/test/CodeGenCXX/constexpr-late-instantiation.cpp new file mode 100644 index 0000000000000..1c8eef73f2dda --- /dev/null +++ b/clang/test/CodeGenCXX/constexpr-late-instantiation.cpp @@ -0,0 +1,17 @@ +// Make sure foo is instantiated and we don't get a link error +// RUN: %clang_cc1 -S -emit-llvm -triple %itanium_abi_triple %s -o- | FileCheck %s + +template <typename T> +constexpr T foo(T a); + +// CHECK-LABEL: define {{.*}} @main +int main() { + // CHECK: call {{.*}} @_Z3fooIiET_S0_ + int k = foo<int>(5); +} +// CHECK: } + +template <typename T> +constexpr T foo(T a) { + return a; +} diff --git a/clang/test/SemaCXX/constexpr-late-instantiation.cpp b/clang/test/SemaCXX/constexpr-late-instantiation.cpp new file mode 100644 index 0000000000000..ec8e071217c1d --- /dev/null +++ b/clang/test/SemaCXX/constexpr-late-instantiation.cpp @@ -0,0 +1,15 @@ +// RUN: %clang_cc1 %s -fsyntax-only -verify + +template <typename T> +constexpr T foo(T a); // expected-note {{declared here}} + +int main() { + int k = foo<int>(5); // Ok + constexpr int j = // expected-error {{constexpr variable 'j' must be initialized by a constant expression}} + foo<int>(5); // expected-note {{undefined function 'foo<int>' cannot be used in a constant expression}} +} + +template <typename T> +constexpr T foo(T a) { + return a; +} _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
