Author: phosek Date: Mon Dec 3 19:25:25 2018 New Revision: 348234 URL: http://llvm.org/viewvc/llvm-project?rev=348234&view=rev Log: [Sema] Provide -fvisibility-global-new-delete-hidden option
When the global new and delete operators aren't declared, Clang provides and implicit declaration, but this declaration currently always uses the default visibility. This is a problem when the C++ library itself is being built with non-default visibility because the implicit declaration will force the new and delete operators to have the default visibility unlike the rest of the library. The existing workaround is to use assembly to enforce the visiblity: https://fuchsia.googlesource.com/zircon/+/master/system/ulib/zxcpp/new.cpp#108 but that solution is not always available, e.g. in the case of of libFuzzer which is using an internal version of libc++ that's also built with -fvisibility=hidden where the existing behavior is causing issues. This change introduces a new option -fvisibility-global-new-delete-hidden which makes the implicit declaration of the global new and delete operators hidden. Differential Revision: https://reviews.llvm.org/D53787 Modified: cfe/trunk/include/clang/Basic/LangOptions.def cfe/trunk/include/clang/Driver/Options.td cfe/trunk/lib/Driver/ToolChains/Clang.cpp cfe/trunk/lib/Frontend/CompilerInvocation.cpp cfe/trunk/lib/Sema/SemaExprCXX.cpp Modified: cfe/trunk/include/clang/Basic/LangOptions.def URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/LangOptions.def?rev=348234&r1=348233&r2=348234&view=diff ============================================================================== --- cfe/trunk/include/clang/Basic/LangOptions.def (original) +++ cfe/trunk/include/clang/Basic/LangOptions.def Mon Dec 3 19:25:25 2018 @@ -227,7 +227,8 @@ BENIGN_LANGOPT(DumpRecordLayouts , 1, 0, BENIGN_LANGOPT(DumpRecordLayoutsSimple , 1, 0, "dumping the layout of IRgen'd records in a simple form") BENIGN_LANGOPT(DumpVTableLayouts , 1, 0, "dumping the layouts of emitted vtables") LANGOPT(NoConstantCFStrings , 1, 0, "no constant CoreFoundation strings") -BENIGN_LANGOPT(InlineVisibilityHidden , 1, 0, "hidden default visibility for inline C++ methods") +BENIGN_LANGOPT(InlineVisibilityHidden , 1, 0, "hidden visibility for inline C++ methods") +LANGOPT(GlobalAllocationFunctionVisibilityHidden , 1, 0, "hidden visibility for global operator new and delete declaration") BENIGN_LANGOPT(ParseUnknownAnytype, 1, 0, "__unknown_anytype") BENIGN_LANGOPT(DebuggerSupport , 1, 0, "debugger support") BENIGN_LANGOPT(DebuggerCastResultToId, 1, 0, "for 'po' in the debugger, cast the result to id if it is of unknown type") Modified: cfe/trunk/include/clang/Driver/Options.td URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Driver/Options.td?rev=348234&r1=348233&r2=348234&view=diff ============================================================================== --- cfe/trunk/include/clang/Driver/Options.td (original) +++ cfe/trunk/include/clang/Driver/Options.td Mon Dec 3 19:25:25 2018 @@ -1734,6 +1734,8 @@ def fvisibility_inlines_hidden : Flag<[" def fvisibility_ms_compat : Flag<["-"], "fvisibility-ms-compat">, Group<f_Group>, HelpText<"Give global types 'default' visibility and global functions and " "variables 'hidden' visibility by default">; +def fvisibility_global_new_delete_hidden : Flag<["-"], "fvisibility-global-new-delete-hidden">, Group<f_Group>, + HelpText<"Give global C++ operator new and delete declarations hidden visibility">, Flags<[CC1Option]>; def fwhole_program_vtables : Flag<["-"], "fwhole-program-vtables">, Group<f_Group>, Flags<[CoreOption, CC1Option]>, HelpText<"Enables whole-program vtable optimization. Requires -flto">; Modified: cfe/trunk/lib/Driver/ToolChains/Clang.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Driver/ToolChains/Clang.cpp?rev=348234&r1=348233&r2=348234&view=diff ============================================================================== --- cfe/trunk/lib/Driver/ToolChains/Clang.cpp (original) +++ cfe/trunk/lib/Driver/ToolChains/Clang.cpp Mon Dec 3 19:25:25 2018 @@ -4329,6 +4329,7 @@ void Clang::ConstructJob(Compilation &C, } Args.AddLastArg(CmdArgs, options::OPT_fvisibility_inlines_hidden); + Args.AddLastArg(CmdArgs, options::OPT_fvisibility_global_new_delete_hidden); Args.AddLastArg(CmdArgs, options::OPT_ftlsmodel_EQ); Modified: cfe/trunk/lib/Frontend/CompilerInvocation.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Frontend/CompilerInvocation.cpp?rev=348234&r1=348233&r2=348234&view=diff ============================================================================== --- cfe/trunk/lib/Frontend/CompilerInvocation.cpp (original) +++ cfe/trunk/lib/Frontend/CompilerInvocation.cpp Mon Dec 3 19:25:25 2018 @@ -2487,6 +2487,9 @@ static void ParseLangArgs(LangOptions &O if (Args.hasArg(OPT_fvisibility_inlines_hidden)) Opts.InlineVisibilityHidden = 1; + if (Args.hasArg(OPT_fvisibility_global_new_delete_hidden)) + Opts.GlobalAllocationFunctionVisibilityHidden = 1; + if (Args.hasArg(OPT_ftrapv)) { Opts.setSignedOverflowBehavior(LangOptions::SOB_Trapping); // Set the handler, if one is specified. Modified: cfe/trunk/lib/Sema/SemaExprCXX.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExprCXX.cpp?rev=348234&r1=348233&r2=348234&view=diff ============================================================================== --- cfe/trunk/lib/Sema/SemaExprCXX.cpp (original) +++ cfe/trunk/lib/Sema/SemaExprCXX.cpp Mon Dec 3 19:25:25 2018 @@ -2816,9 +2816,10 @@ void Sema::DeclareGlobalAllocationFuncti // Global allocation functions should always be visible. Alloc->setVisibleDespiteOwningModule(); - // Implicit sized deallocation functions always have default visibility. - Alloc->addAttr( - VisibilityAttr::CreateImplicit(Context, VisibilityAttr::Default)); + Alloc->addAttr(VisibilityAttr::CreateImplicit( + Context, LangOpts.GlobalAllocationFunctionVisibilityHidden + ? VisibilityAttr::Hidden + : VisibilityAttr::Default)); llvm::SmallVector<ParmVarDecl *, 3> ParamDecls; for (QualType T : Params) { _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
