llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-clang-modules Author: Haojian Wu (hokein) <details> <summary>Changes</summary> See discussion in https://github.com/llvm/llvm-project/issues/125071. Makes the note clear for unreachable case: Before: ``` ./hoge.h:5:12: warning: instantiation of function 'x<int>' required here, but no definition is available [-Wundefined-func-template] 5 | void f() { x<int>(); } | ^ ./shared_ptr2.h:4:6: note: forward declaration of template entity is here 4 | void x() { T t; (void)t; } | ^ ./hoge.h:5:12: note: add an explicit instantiation declaration to suppress this warning if 'x<int>' is explicitly instantiated in another translation unit 5 | void f() { x<int>(); } | ``` After: ``` ./hoge.h:5:12: warning: instantiation of function 'x<int>' required here, but no definition is available [-Wundefined-func-template] 5 | void f() { x<int>(); } | ^ ./shared_ptr2.h:4:6: note: declaration of template entity is unreachable here 4 | void x() { T t; (void)t; } | ^ 1 warning generated. ``` --- Full diff: https://github.com/llvm/llvm-project/pull/129031.diff 8 Files Affected: - (modified) clang/include/clang/Basic/DiagnosticSemaKinds.td (+2) - (modified) clang/include/clang/Sema/Sema.h (+5-7) - (modified) clang/lib/Sema/SemaTemplate.cpp (+7-7) - (modified) clang/lib/Sema/SemaTemplateInstantiateDecl.cpp (+19-9) - (added) clang/test/Modules/Inputs/undefined-template/hoge.h (+7) - (added) clang/test/Modules/Inputs/undefined-template/module.modulemap (+7) - (added) clang/test/Modules/Inputs/undefined-template/shared_ptr2.h (+4) - (added) clang/test/Modules/diag-undefined-template.cpp (+10) ``````````diff diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td index f10af8f5bd6b2..80f2d54c8a893 100644 --- a/clang/include/clang/Basic/DiagnosticSemaKinds.td +++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td @@ -5654,6 +5654,8 @@ def warn_func_template_missing : Warning<"instantiation of function %q0 " InGroup<UndefinedFuncTemplate>, DefaultIgnore; def note_forward_template_decl : Note< "forward declaration of template entity is here">; +def note_unreachable_template_decl + : Note<"unreachable declaration of template entity is here">; def note_inst_declaration_hint : Note<"add an explicit instantiation " "declaration to suppress this warning if %q0 is explicitly instantiated in " "another translation unit">; diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h index a501b901862b6..dfe1c0342252f 100644 --- a/clang/include/clang/Sema/Sema.h +++ b/clang/include/clang/Sema/Sema.h @@ -11183,13 +11183,11 @@ class Sema final : public SemaBase { /// Determine whether we would be unable to instantiate this template (because /// it either has no definition, or is in the process of being instantiated). - bool DiagnoseUninstantiableTemplate(SourceLocation PointOfInstantiation, - NamedDecl *Instantiation, - bool InstantiatedFromMember, - const NamedDecl *Pattern, - const NamedDecl *PatternDef, - TemplateSpecializationKind TSK, - bool Complain = true); + bool DiagnoseUninstantiableTemplate( + SourceLocation PointOfInstantiation, NamedDecl *Instantiation, + bool InstantiatedFromMember, const NamedDecl *Pattern, + const NamedDecl *PatternDef, TemplateSpecializationKind TSK, + bool Complain = true, bool *Unreachable = nullptr); /// DiagnoseTemplateParameterShadow - Produce a diagnostic complaining /// that the template parameter 'PrevDecl' is being shadowed by a new diff --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp index 38fa3ff3ab5b4..9a0e37f344287 100644 --- a/clang/lib/Sema/SemaTemplate.cpp +++ b/clang/lib/Sema/SemaTemplate.cpp @@ -759,13 +759,11 @@ Sema::BuildDependentDeclRefExpr(const CXXScopeSpec &SS, TemplateArgs); } -bool Sema::DiagnoseUninstantiableTemplate(SourceLocation PointOfInstantiation, - NamedDecl *Instantiation, - bool InstantiatedFromMember, - const NamedDecl *Pattern, - const NamedDecl *PatternDef, - TemplateSpecializationKind TSK, - bool Complain /*= true*/) { +bool Sema::DiagnoseUninstantiableTemplate( + SourceLocation PointOfInstantiation, NamedDecl *Instantiation, + bool InstantiatedFromMember, const NamedDecl *Pattern, + const NamedDecl *PatternDef, TemplateSpecializationKind TSK, + bool Complain /*= true*/, bool *Unreachable) { assert(isa<TagDecl>(Instantiation) || isa<FunctionDecl>(Instantiation) || isa<VarDecl>(Instantiation)); @@ -778,6 +776,8 @@ bool Sema::DiagnoseUninstantiableTemplate(SourceLocation PointOfInstantiation, if (!hasReachableDefinition(const_cast<NamedDecl *>(PatternDef), &SuggestedDef, /*OnlyNeedComplete*/ false)) { + if (Unreachable) + *Unreachable = true; // If we're allowed to diagnose this and recover, do so. bool Recover = Complain && !isSFINAEContext(); if (Complain) diff --git a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp index 1f42f9500959e..398e41b236ae4 100644 --- a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp +++ b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp @@ -5052,12 +5052,15 @@ void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation, PatternDef = nullptr; } + // True is the template definition is unreachable, otherwise false. + bool Unreachable = false; // FIXME: We need to track the instantiation stack in order to know which // definitions should be visible within this instantiation. - if (DiagnoseUninstantiableTemplate(PointOfInstantiation, Function, - Function->getInstantiatedFromMemberFunction(), - PatternDecl, PatternDef, TSK, - /*Complain*/DefinitionRequired)) { + if (DiagnoseUninstantiableTemplate( + PointOfInstantiation, Function, + Function->getInstantiatedFromMemberFunction(), PatternDecl, + PatternDef, TSK, + /*Complain*/ DefinitionRequired, &Unreachable)) { if (DefinitionRequired) Function->setInvalidDecl(); else if (TSK == TSK_ExplicitInstantiationDefinition || @@ -5082,11 +5085,18 @@ void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation, if (AtEndOfTU && !getDiagnostics().hasErrorOccurred() && !getSourceManager().isInSystemHeader(PatternDecl->getBeginLoc())) { Diag(PointOfInstantiation, diag::warn_func_template_missing) - << Function; - Diag(PatternDecl->getLocation(), diag::note_forward_template_decl); - if (getLangOpts().CPlusPlus11) - Diag(PointOfInstantiation, diag::note_inst_declaration_hint) - << Function; + << Function; + if (Unreachable) { + // FIXME: would be nice to mention which module the function template + // comes from. + Diag(PatternDecl->getLocation(), + diag::note_unreachable_template_decl); + } else { + Diag(PatternDecl->getLocation(), diag::note_forward_template_decl); + if (getLangOpts().CPlusPlus11) + Diag(PointOfInstantiation, diag::note_inst_declaration_hint) + << Function; + } } } diff --git a/clang/test/Modules/Inputs/undefined-template/hoge.h b/clang/test/Modules/Inputs/undefined-template/hoge.h new file mode 100644 index 0000000000000..c67e85ed06734 --- /dev/null +++ b/clang/test/Modules/Inputs/undefined-template/hoge.h @@ -0,0 +1,7 @@ +#pragma once + +#include "shared_ptr2.h" + +inline void f() { + x<int>(); +} diff --git a/clang/test/Modules/Inputs/undefined-template/module.modulemap b/clang/test/Modules/Inputs/undefined-template/module.modulemap new file mode 100644 index 0000000000000..89cc78cd5a2de --- /dev/null +++ b/clang/test/Modules/Inputs/undefined-template/module.modulemap @@ -0,0 +1,7 @@ +module hoge { + header "hoge.h" +} + +module shared_ptr2 { + header "shared_ptr2.h" +} diff --git a/clang/test/Modules/Inputs/undefined-template/shared_ptr2.h b/clang/test/Modules/Inputs/undefined-template/shared_ptr2.h new file mode 100644 index 0000000000000..495cc6fe539c1 --- /dev/null +++ b/clang/test/Modules/Inputs/undefined-template/shared_ptr2.h @@ -0,0 +1,4 @@ +#pragma once + +template<class T> +void x() { } diff --git a/clang/test/Modules/diag-undefined-template.cpp b/clang/test/Modules/diag-undefined-template.cpp new file mode 100644 index 0000000000000..027984c3125f3 --- /dev/null +++ b/clang/test/Modules/diag-undefined-template.cpp @@ -0,0 +1,10 @@ +// RUN: rm -rf %t +// RUN: %clang_cc1 -std=c++20 -fmodules -fmodules-cache-path=%t -I%S/Inputs/undefined-template \ +// RUN: -Wundefined-func-template \ +// RUN: -fimplicit-module-maps %s 2>&1 | grep "unreachable declaration of template entity is her" + +#include "hoge.h" + +int main() { + f(); +} `````````` </details> https://github.com/llvm/llvm-project/pull/129031 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
