From: Richard Smith Date: Mon, 22 Jun 2015 21:15:01 +0000 (+0000) Subject: [modules] Add a flag to disable the feature that permits conflicting redefinitions... X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=5fa53a9a30272bf4dd18c7d33d1c3a0b0c696212;p=clang [modules] Add a flag to disable the feature that permits conflicting redefinitions of internal-linkage symbols that are not visible. Such conflicts are an accident waiting to happen, and this feature conflicts with the desire to include existing headers into multiple modules and merge the results. (In an ideal world, it should not be possible to export internal linkage symbols from a module, but sadly the glibc and libstdc++ headers provide 'static inline' functions in a few cases.) git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@240335 91177308-0d34-0410-b5e6-96231b3b80d8 --- diff --git a/include/clang/Basic/LangOptions.def b/include/clang/Basic/LangOptions.def index bef122f093..b27605b15d 100644 --- a/include/clang/Basic/LangOptions.def +++ b/include/clang/Basic/LangOptions.def @@ -130,6 +130,7 @@ COMPATIBLE_LANGOPT(ModulesStrictDeclUse, 1, 0, "require declaration of module us BENIGN_LANGOPT(ModulesErrorRecovery, 1, 1, "automatically import modules as needed when performing error recovery") BENIGN_LANGOPT(ImplicitModules, 1, 1, "build modules that are not specified via -fmodule-file") COMPATIBLE_LANGOPT(ModulesLocalVisibility, 1, 0, "local submodule visibility") +COMPATIBLE_LANGOPT(ModulesHideInternalLinkage, 1, 1, "hiding non-visible internal linkage declarations from redeclaration lookup") COMPATIBLE_LANGOPT(Optimize , 1, 0, "__OPTIMIZE__ predefined macro") COMPATIBLE_LANGOPT(OptimizeSize , 1, 0, "__OPTIMIZE_SIZE__ predefined macro") LANGOPT(Static , 1, 0, "__STATIC__ predefined macro (as opposed to __DYNAMIC__)") diff --git a/include/clang/Driver/CC1Options.td b/include/clang/Driver/CC1Options.td index f2ef71e2f9..60cc6ec115 100644 --- a/include/clang/Driver/CC1Options.td +++ b/include/clang/Driver/CC1Options.td @@ -369,6 +369,10 @@ def fmodules_local_submodule_visibility : Flag<["-"], "fmodules-local-submodule-visibility">, HelpText<"Enforce name visibility rules across submodules of the same " "top-level module.">; +def fno_modules_hide_internal_linkage : + Flag<["-"], "fno-modules-hide-internal-linkage">, + HelpText<"Make all declarations visible to redeclaration lookup, " + "even if they have internal linkage.">; def fconcepts_ts : Flag<["-"], "fconcepts-ts">, HelpText<"Enable C++ Extensions for Concepts.">; diff --git a/include/clang/Sema/Sema.h b/include/clang/Sema/Sema.h index 4d81526259..df5182b52f 100644 --- a/include/clang/Sema/Sema.h +++ b/include/clang/Sema/Sema.h @@ -277,7 +277,9 @@ class Sema { // it will keep having external linkage. If it has internal linkage, we // will not link it. Since it has no previous decls, it will remain // with internal linkage. - return isVisible(Old) || New->isExternallyVisible(); + if (getLangOpts().ModulesHideInternalLinkage) + return isVisible(Old) || New->isExternallyVisible(); + return true; } public: diff --git a/lib/Frontend/CompilerInvocation.cpp b/lib/Frontend/CompilerInvocation.cpp index 7a3391685a..2d26548db3 100644 --- a/lib/Frontend/CompilerInvocation.cpp +++ b/lib/Frontend/CompilerInvocation.cpp @@ -1521,6 +1521,8 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK, Args.hasArg(OPT_fmodules_decluse) || Opts.ModulesStrictDeclUse; Opts.ModulesLocalVisibility = Args.hasArg(OPT_fmodules_local_submodule_visibility); + Opts.ModulesHideInternalLinkage = + !Args.hasArg(OPT_fno_modules_hide_internal_linkage); Opts.ModulesSearchAll = Opts.Modules && !Args.hasArg(OPT_fno_modules_search_all) && Args.hasArg(OPT_fmodules_search_all); diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp index cb1be8d505..ee03994058 100644 --- a/lib/Sema/SemaDecl.cpp +++ b/lib/Sema/SemaDecl.cpp @@ -1804,7 +1804,8 @@ static void filterNonConflictingPreviousDecls(Sema &S, NamedDecl *decl, LookupResult &previous){ // This is only interesting when modules are enabled. - if (!S.getLangOpts().Modules && !S.getLangOpts().ModulesLocalVisibility) + if ((!S.getLangOpts().Modules && !S.getLangOpts().ModulesLocalVisibility) || + !S.getLangOpts().ModulesHideInternalLinkage) return; // Empty sets are uninteresting. @@ -3453,8 +3454,9 @@ void Sema::MergeVarDecl(VarDecl *New, LookupResult &Previous) { New->isThisDeclarationADefinition() == VarDecl::Definition && (Def = Old->getDefinition())) { NamedDecl *Hidden = nullptr; - if (!hasVisibleDefinition(Def, &Hidden) && - (New->getDescribedVarTemplate() || + if (!hasVisibleDefinition(Def, &Hidden) && + (New->getFormalLinkage() == InternalLinkage || + New->getDescribedVarTemplate() || New->getNumTemplateParameterLists() || New->getDeclContext()->isDependentContext())) { // The previous definition is hidden, and multiple definitions are @@ -8946,7 +8948,8 @@ void Sema::AddInitializerToDecl(Decl *RealDecl, Expr *Init, if ((Def = VDecl->getDefinition()) && Def != VDecl) { NamedDecl *Hidden = nullptr; if (!hasVisibleDefinition(Def, &Hidden) && - (VDecl->getDescribedVarTemplate() || + (VDecl->getFormalLinkage() == InternalLinkage || + VDecl->getDescribedVarTemplate() || VDecl->getNumTemplateParameterLists() || VDecl->getDeclContext()->isDependentContext())) { // The previous definition is hidden, and multiple definitions are @@ -10367,7 +10370,8 @@ Sema::CheckForFunctionRedefinition(FunctionDecl *FD, // in this case? That may be necessary for functions that return local types // through a deduced return type, or instantiate templates with local types. if (!hasVisibleDefinition(Definition) && - (Definition->isInlineSpecified() || + (Definition->getFormalLinkage() == InternalLinkage || + Definition->isInlineSpecified() || Definition->getDescribedFunctionTemplate() || Definition->getNumTemplateParameterLists())) return; diff --git a/test/Modules/submodules-merge-defs.cpp b/test/Modules/submodules-merge-defs.cpp index 94c0fd354c..6f2754be46 100644 --- a/test/Modules/submodules-merge-defs.cpp +++ b/test/Modules/submodules-merge-defs.cpp @@ -3,7 +3,7 @@ // RUN: %clang_cc1 -x c++ -std=c++11 -fmodules-cache-path=%t -fmodules -fimplicit-module-maps -I %S/Inputs/submodules-merge-defs %s -verify -fno-modules-error-recovery // RUN: %clang_cc1 -x c++ -std=c++11 -fmodules-cache-path=%t -fmodules -fimplicit-module-maps -I %S/Inputs/submodules-merge-defs %s -verify -fno-modules-error-recovery -fmodules-local-submodule-visibility -DTEXTUAL // RUN: %clang_cc1 -x c++ -std=c++11 -fmodules-cache-path=%t -fmodules -fimplicit-module-maps -I %S/Inputs/submodules-merge-defs %s -verify -fno-modules-error-recovery -fmodules-local-submodule-visibility -// RUN: %clang_cc1 -x c++ -std=c++11 -fmodules-cache-path=%t -fimplicit-module-maps -I %S/Inputs/submodules-merge-defs %s -verify -fno-modules-error-recovery -fmodules-local-submodule-visibility -DTEXTUAL -DEARLY_INDIRECT_INCLUDE +// RUN: %clang_cc1 -x c++ -std=c++11 -fmodules-cache-path=%t -fimplicit-module-maps -I %S/Inputs/submodules-merge-defs %s -verify -fno-modules-error-recovery -fmodules-local-submodule-visibility -DTEXTUAL -DEARLY_INDIRECT_INCLUDE -fno-modules-hide-internal-linkage // RUN: %clang_cc1 -x c++ -std=c++11 -fmodules-cache-path=%t -fmodules -fimplicit-module-maps -I %S/Inputs/submodules-merge-defs %s -verify -fno-modules-error-recovery -fmodules-local-submodule-visibility -fmodule-feature use_defs_twice -DIMPORT_USE_2 // Trigger import of definitions, but don't make them visible. @@ -92,3 +92,8 @@ template class K> struct J; J<> post_j2; FriendDefArg::Y friend_def_arg; FriendDefArg::D<> friend_def_arg_d; + +#ifdef TEXTUAL +#include "use-defs.h" +void use_static_inline() { StaticInline::g({}); } +#endif