コード例 #1
0
void Cse523AsmPrinter::EmitEndOfAsmFile(Module &M) {
    if (Subtarget->isTargetMacho()) {
        // All darwin targets use mach-o.
        MachineModuleInfoMachO &MMIMacho =
            MMI->getObjFileInfo<MachineModuleInfoMachO>();

        // Output stubs for dynamically-linked functions.
        MachineModuleInfoMachO::SymbolListTy Stubs;

        Stubs = MMIMacho.GetFnStubList();
        if (!Stubs.empty()) {
            const MCSection *TheSection =
                OutContext.getMachOSection("__IMPORT", "__jump_table",
                        MCSectionMachO::S_SYMBOL_STUBS |
                        MCSectionMachO::S_ATTR_SELF_MODIFYING_CODE |
                        MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
                        5, SectionKind::getMetadata());
            OutStreamer.SwitchSection(TheSection);

            for (unsigned i = 0, e = Stubs.size(); i != e; ++i) {
                // L_foo$stub:
                OutStreamer.EmitLabel(Stubs[i].first);
                //   .indirect_symbol _foo
                OutStreamer.EmitSymbolAttribute(Stubs[i].second.getPointer(),
                        MCSA_IndirectSymbol);
                // hlt; hlt; hlt; hlt; hlt     hlt = 0xf4.
                const char HltInsts[] = "\xf4\xf4\xf4\xf4\xf4";
                OutStreamer.EmitBytes(StringRef(HltInsts, 5));
            }

            Stubs.clear();
            OutStreamer.AddBlankLine();
        }

        // Output stubs for external and common global variables.
        Stubs = MMIMacho.GetGVStubList();
        if (!Stubs.empty()) {
            const MCSection *TheSection =
                OutContext.getMachOSection("__IMPORT", "__pointers",
                        MCSectionMachO::S_NON_LAZY_SYMBOL_POINTERS,
                        SectionKind::getMetadata());
            OutStreamer.SwitchSection(TheSection);

            for (unsigned i = 0, e = Stubs.size(); i != e; ++i) {
                // L_foo$non_lazy_ptr:
                OutStreamer.EmitLabel(Stubs[i].first);
                // .indirect_symbol _foo
                MachineModuleInfoImpl::StubValueTy &MCSym = Stubs[i].second;
                OutStreamer.EmitSymbolAttribute(MCSym.getPointer(),
                        MCSA_IndirectSymbol);
                // .long 0
                if (MCSym.getInt())
                    // External to current translation unit.
                    OutStreamer.EmitIntValue(0, 4/*size*/);
                else
                    // Internal to current translation unit.
                    //
                    // When we place the LSDA into the TEXT section, the type info
                    // pointers need to be indirect and pc-rel. We accomplish this by
                    // using NLPs.  However, sometimes the types are local to the file. So
                    // we need to fill in the value for the NLP in those cases.
                    OutStreamer.EmitValue(MCSymbolRefExpr::Create(MCSym.getPointer(),
                                OutContext), 4/*size*/);
            }
            Stubs.clear();
            OutStreamer.AddBlankLine();
        }

        Stubs = MMIMacho.GetHiddenGVStubList();
        if (!Stubs.empty()) {
            OutStreamer.SwitchSection(getObjFileLowering().getDataSection());
            EmitAlignment(2);

            for (unsigned i = 0, e = Stubs.size(); i != e; ++i) {
                // L_foo$non_lazy_ptr:
                OutStreamer.EmitLabel(Stubs[i].first);
                // .long _foo
                OutStreamer.EmitValue(MCSymbolRefExpr::
                        Create(Stubs[i].second.getPointer(),
                            OutContext), 4/*size*/);
            }
            Stubs.clear();
            OutStreamer.AddBlankLine();
        }

        SM.serializeToStackMapSection();

        // Funny Darwin hack: This flag tells the linker that no global symbols
        // contain code that falls through to other global symbols (e.g. the obvious
        // implementation of multiple entry points).  If this doesn't occur, the
        // linker can safely perform dead code stripping.  Since LLVM never
        // generates code that does this, it is always safe to set.
        OutStreamer.EmitAssemblerFlag(MCAF_SubsectionsViaSymbols);
    }

    if (Subtarget->isTargetWindows() && !Subtarget->isTargetCygMing() &&
            MMI->usesVAFloatArgument()) {
        StringRef SymbolName = Subtarget->is64Bit() ? "_fltused" : "__fltused";
        MCSymbol *S = MMI->getContext().GetOrCreateSymbol(SymbolName);
        OutStreamer.EmitSymbolAttribute(S, MCSA_Global);
    }

    if (Subtarget->isTargetCOFF()) {
        Cse523COFFMachineModuleInfo &COFFMMI =
            MMI->getObjFileInfo<Cse523COFFMachineModuleInfo>();

        // Emit type information for external functions
        typedef Cse523COFFMachineModuleInfo::externals_iterator externals_iterator;
        for (externals_iterator I = COFFMMI.externals_begin(),
                E = COFFMMI.externals_end();
                I != E; ++I) {
            OutStreamer.BeginCOFFSymbolDef(CurrentFnSym);
            OutStreamer.EmitCOFFSymbolStorageClass(COFF::IMAGE_SYM_CLASS_EXTERNAL);
            OutStreamer.EmitCOFFSymbolType(COFF::IMAGE_SYM_DTYPE_FUNCTION
                    << COFF::SCT_COMPLEX_TYPE_SHIFT);
            OutStreamer.EndCOFFSymbolDef();
        }

        // Necessary for dllexport support
        std::vector<const MCSymbol*> DLLExportedFns, DLLExportedGlobals;

        for (Module::const_iterator I = M.begin(), E = M.end(); I != E; ++I)
            if (I->hasDLLExportStorageClass())
                DLLExportedFns.push_back(getSymbol(I));

        for (Module::const_global_iterator I = M.global_begin(),
                E = M.global_end(); I != E; ++I)
            if (I->hasDLLExportStorageClass())
                DLLExportedGlobals.push_back(getSymbol(I));

        for (Module::const_alias_iterator I = M.alias_begin(), E = M.alias_end();
                I != E; ++I) {
            const GlobalValue *GV = I;
            if (!GV->hasDLLExportStorageClass())
                continue;

            while (const GlobalAlias *A = dyn_cast<GlobalAlias>(GV))
                GV = A->getAliasedGlobal();

            if (isa<Function>(GV))
                DLLExportedFns.push_back(getSymbol(I));
            else if (isa<GlobalVariable>(GV))
                DLLExportedGlobals.push_back(getSymbol(I));
        }

        // Output linker support code for dllexported globals on windows.
        if (!DLLExportedGlobals.empty() || !DLLExportedFns.empty()) {
            const TargetLoweringObjectFileCOFF &TLOFCOFF =
                static_cast<const TargetLoweringObjectFileCOFF&>(getObjFileLowering());

            OutStreamer.SwitchSection(TLOFCOFF.getDrectveSection());
            SmallString<128> name;
            for (unsigned i = 0, e = DLLExportedGlobals.size(); i != e; ++i) {
                if (Subtarget->isTargetWindows())
                    name = " /EXPORT:";
                else
                    name = " -export:";
                name += DLLExportedGlobals[i]->getName();
                if (Subtarget->isTargetWindows())
                    name += ",DATA";
                else
                    name += ",data";
                OutStreamer.EmitBytes(name);
            }

            for (unsigned i = 0, e = DLLExportedFns.size(); i != e; ++i) {
                if (Subtarget->isTargetWindows())
                    name = " /EXPORT:";
                else
                    name = " -export:";
                name += DLLExportedFns[i]->getName();
                OutStreamer.EmitBytes(name);
            }
        }
    }

    if (Subtarget->isTargetELF()) {
        const TargetLoweringObjectFileELF &TLOFELF =
            static_cast<const TargetLoweringObjectFileELF &>(getObjFileLowering());

        MachineModuleInfoELF &MMIELF = MMI->getObjFileInfo<MachineModuleInfoELF>();

        // Output stubs for external and common global variables.
        MachineModuleInfoELF::SymbolListTy Stubs = MMIELF.GetGVStubList();
        if (!Stubs.empty()) {
            OutStreamer.SwitchSection(TLOFELF.getDataRelSection());
            const DataLayout *TD = TM.getDataLayout();

            for (unsigned i = 0, e = Stubs.size(); i != e; ++i) {
                OutStreamer.EmitLabel(Stubs[i].first);
                OutStreamer.EmitSymbolValue(Stubs[i].second.getPointer(),
                        TD->getPointerSize());
            }
            Stubs.clear();
        }
    }
}