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Diffstat (limited to 'lib/ReaderWriter/PECOFF/LinkerGeneratedSymbolFile.h')
| -rw-r--r-- | lib/ReaderWriter/PECOFF/LinkerGeneratedSymbolFile.h | 309 |
1 files changed, 0 insertions, 309 deletions
diff --git a/lib/ReaderWriter/PECOFF/LinkerGeneratedSymbolFile.h b/lib/ReaderWriter/PECOFF/LinkerGeneratedSymbolFile.h deleted file mode 100644 index b9764d70bb3bf..0000000000000 --- a/lib/ReaderWriter/PECOFF/LinkerGeneratedSymbolFile.h +++ /dev/null @@ -1,309 +0,0 @@ -//===- lib/ReaderWriter/PECOFF/LinkerGeneratedSymbolFile.h ----------------===// -// -// The LLVM Linker -// -// This file is distributed under the University of Illinois Open Source -// License. See LICENSE.TXT for details. -// -//===----------------------------------------------------------------------===// - -#include "Atoms.h" -#include "lld/Core/Simple.h" -#include "lld/ReaderWriter/PECOFFLinkingContext.h" -#include "llvm/Support/Allocator.h" -#include <algorithm> -#include <mutex> - -using llvm::COFF::WindowsSubsystem; - -namespace lld { -namespace pecoff { - -bool findDecoratedSymbol(PECOFFLinkingContext *ctx, - std::string sym, std::string &res); - -namespace impl { - -/// The defined atom for dllexported symbols with __imp_ prefix. -class ImpPointerAtom : public COFFLinkerInternalAtom { -public: - ImpPointerAtom(const File &file, StringRef symbolName, uint64_t ordinal) - : COFFLinkerInternalAtom(file, /*oridnal*/ 0, std::vector<uint8_t>(4), - symbolName), - _ordinal(ordinal) {} - - uint64_t ordinal() const override { return _ordinal; } - Scope scope() const override { return scopeGlobal; } - ContentType contentType() const override { return typeData; } - Alignment alignment() const override { return Alignment(4); } - ContentPermissions permissions() const override { return permR__; } - -private: - uint64_t _ordinal; -}; - -class ImpSymbolFile : public SimpleFile { -public: - ImpSymbolFile(StringRef defsym, StringRef undefsym, uint64_t ordinal, - bool is64) - : SimpleFile(defsym), _undefined(*this, undefsym), - _defined(*this, defsym, ordinal) { - SimpleReference *ref; - if (is64) { - ref = new SimpleReference(Reference::KindNamespace::COFF, - Reference::KindArch::x86_64, - llvm::COFF::IMAGE_REL_AMD64_ADDR32, - 0, &_undefined, 0); - } else { - ref = new SimpleReference(Reference::KindNamespace::COFF, - Reference::KindArch::x86, - llvm::COFF::IMAGE_REL_I386_DIR32, - 0, &_undefined, 0); - } - _defined.addReference(std::unique_ptr<SimpleReference>(ref)); - addAtom(_defined); - addAtom(_undefined); - }; - -private: - SimpleUndefinedAtom _undefined; - ImpPointerAtom _defined; -}; - -// A file to make Resolver to resolve a symbol TO instead of a symbol FROM, -// using fallback mechanism for an undefined symbol. One can virtually rename an -// undefined symbol using this file. -class SymbolRenameFile : public SimpleFile { -public: - SymbolRenameFile(StringRef from, StringRef to) - : SimpleFile("<symbol-rename>"), _fromSym(from), _toSym(to), - _from(*this, _fromSym, &_to), _to(*this, _toSym) { - addAtom(_from); - }; - -private: - std::string _fromSym; - std::string _toSym; - COFFUndefinedAtom _from; - COFFUndefinedAtom _to; -}; - -} // namespace impl - -// A virtual file containing absolute symbol __ImageBase. __ImageBase (or -// ___ImageBase on x86) is a linker-generated symbol whose address is the same -// as the image base address. -class LinkerGeneratedSymbolFile : public SimpleFile { -public: - LinkerGeneratedSymbolFile(const PECOFFLinkingContext &ctx) - : SimpleFile("<linker-internal-file>"), - _imageBaseAtom(*this, ctx.decorateSymbol("__ImageBase"), - Atom::scopeGlobal, ctx.getBaseAddress()) { - addAtom(_imageBaseAtom); - }; - -private: - SimpleAbsoluteAtom _imageBaseAtom; -}; - -// A LocallyImporteSymbolFile is an archive file containing __imp_ -// symbols for local use. -// -// For each defined symbol, linker creates an implicit defined symbol -// by appending "__imp_" prefix to the original name. The content of -// the implicit symbol is a pointer to the original symbol -// content. This feature allows one to compile and link the following -// code without error, although _imp__hello is not defined in the -// code. (the leading "_" in this example is automatically appended, -// assuming it's x86.) -// -// void hello() { printf("Hello\n"); } -// extern void (*_imp__hello)(); -// int main() { -// _imp__hello(); -// return 0; -// } -// -// This odd feature is for the compatibility with MSVC link.exe. -class LocallyImportedSymbolFile : public SimpleArchiveLibraryFile { -public: - LocallyImportedSymbolFile(const PECOFFLinkingContext &ctx) - : SimpleArchiveLibraryFile("__imp_"), _is64(ctx.is64Bit()), - _ordinal(0) {} - - File *find(StringRef sym, bool dataSymbolOnly) override { - std::string prefix = "__imp_"; - if (!sym.startswith(prefix)) - return nullptr; - StringRef undef = sym.substr(prefix.size()); - return new (_alloc) impl::ImpSymbolFile(sym, undef, _ordinal++, _is64); - } - -private: - bool _is64; - uint64_t _ordinal; - llvm::BumpPtrAllocator _alloc; -}; - -// A ExportedSymbolRenameFile is a virtual archive file for dllexported symbols. -// -// One usually has to specify the exact symbol name to resolve it. That's true -// in most cases for PE/COFF, except the one described below. -// -// DLLExported symbols can be specified using a module definition file. In a -// file, one can write an EXPORT directive followed by symbol names. Such -// symbols may not be fully decorated. -// -// If a symbol FOO is specified to be dllexported by a module definition file, -// linker has to search not only for /FOO/ but also for /FOO@[0-9]+/ for stdcall -// and for /\?FOO@@.+/ for C++. This ambiguous matching semantics does not fit -// well with Resolver. -// -// We could probably modify Resolver to resolve ambiguous symbols, but I think -// we don't want to do that because it'd be rarely used, and only this Windows -// specific feature would use it. It's probably not a good idea to make the core -// linker to be able to deal with it. -// -// So, instead of tweaking Resolver, we chose to do some hack here. An -// ExportedSymbolRenameFile maintains a set containing all possibly defined -// symbol names. That set would be a union of (1) all the defined symbols that -// are already parsed and read and (2) all the defined symbols in archive files -// that are not yet be parsed. -// -// If Resolver asks this file to return an atom for a dllexported symbol, find() -// looks up the set, doing ambiguous matching. If there's a symbol with @ -// prefix, it returns an atom to rename the dllexported symbol, hoping that -// Resolver will find the new symbol with atsign from an archive file at the -// next visit. -class ExportedSymbolRenameFile : public SimpleArchiveLibraryFile { -public: - ExportedSymbolRenameFile(const PECOFFLinkingContext &ctx) - : SimpleArchiveLibraryFile("<export>"), - _ctx(const_cast<PECOFFLinkingContext *>(&ctx)) { - for (PECOFFLinkingContext::ExportDesc &desc : _ctx->getDllExports()) - _exportedSyms.insert(desc.name); - } - - File *find(StringRef sym, bool dataSymbolOnly) override { - typedef PECOFFLinkingContext::ExportDesc ExportDesc; - if (_exportedSyms.count(sym) == 0) - return nullptr; - std::string replace; - if (!findDecoratedSymbol(_ctx, sym.str(), replace)) - return nullptr; - - for (ExportDesc &exp : _ctx->getDllExports()) - if (exp.name == sym) - exp.mangledName = replace; - if (_ctx->deadStrip()) - _ctx->addDeadStripRoot(_ctx->allocate(replace)); - return new (_alloc) impl::SymbolRenameFile(sym, replace); - } - -private: - std::set<std::string> _exportedSyms; - llvm::BumpPtrAllocator _alloc; - PECOFFLinkingContext *_ctx; -}; - -// Windows has not only one but many entry point functions. The -// appropriate one is automatically selected based on the subsystem -// setting and the user-supplied entry point function. -// -// http://msdn.microsoft.com/en-us/library/f9t8842e.aspx -class EntryPointFile : public SimpleFile { -public: - EntryPointFile(const PECOFFLinkingContext &ctx) - : SimpleFile("<entry>"), _ctx(const_cast<PECOFFLinkingContext *>(&ctx)), - _firstTime(true) {} - - const atom_collection<UndefinedAtom> &undefined() const override { - return const_cast<EntryPointFile *>(this)->getUndefinedAtoms(); - } - -private: - const atom_collection<UndefinedAtom> &getUndefinedAtoms() { - std::lock_guard<std::mutex> lock(_mutex); - if (!_firstTime) - return _undefinedAtoms; - _firstTime = false; - - if (_ctx->hasEntry()) { - StringRef entrySym = _ctx->allocate(getEntry()); - _undefinedAtoms._atoms.push_back( - new (_alloc) SimpleUndefinedAtom(*this, entrySym)); - _ctx->setHasEntry(true); - _ctx->setEntrySymbolName(entrySym); - if (_ctx->deadStrip()) - _ctx->addDeadStripRoot(entrySym); - } - return _undefinedAtoms; - } - - // Returns the entry point function name. - std::string getEntry() const { - StringRef opt = _ctx->getEntrySymbolName(); - if (!opt.empty()) { - std::string mangled; - if (findDecoratedSymbol(_ctx, opt, mangled)) - return mangled; - return _ctx->decorateSymbol(opt); - } - return _ctx->decorateSymbol(getDefaultEntry()); - } - - std::string getDefaultEntry() const { - const std::string wWinMainCRTStartup = "wWinMainCRTStartup"; - const std::string WinMainCRTStartup = "WinMainCRTStartup"; - const std::string wmainCRTStartup = "wmainCRTStartup"; - const std::string mainCRTStartup = "mainCRTStartup"; - - if (_ctx->isDll()) { - if (_ctx->getMachineType() == llvm::COFF::IMAGE_FILE_MACHINE_I386) - return "_DllMainCRTStartup@12"; - return "_DllMainCRTStartup"; - } - - // Returns true if a given name exists in an input object file. - auto defined = [&](StringRef name) -> bool { - StringRef sym = _ctx->decorateSymbol(name); - if (_ctx->definedSymbols().count(sym)) - return true; - std::string ignore; - return findDecoratedSymbol(_ctx, sym, ignore); - }; - - switch (_ctx->getSubsystem()) { - case WindowsSubsystem::IMAGE_SUBSYSTEM_UNKNOWN: { - if (defined("wWinMain")) - return wWinMainCRTStartup; - if (defined("WinMain")) - return WinMainCRTStartup; - if (defined("wmain")) - return wmainCRTStartup; - if (!defined("main")) - llvm::errs() << "Cannot infer subsystem; assuming /subsystem:console\n"; - return mainCRTStartup; - } - case WindowsSubsystem::IMAGE_SUBSYSTEM_WINDOWS_GUI: - if (defined("WinMain")) - return WinMainCRTStartup; - return wWinMainCRTStartup; - case WindowsSubsystem::IMAGE_SUBSYSTEM_WINDOWS_CUI: - if (defined("wmain")) - return wmainCRTStartup; - return mainCRTStartup; - default: - return mainCRTStartup; - } - } - - PECOFFLinkingContext *_ctx; - atom_collection_vector<UndefinedAtom> _undefinedAtoms; - std::mutex _mutex; - llvm::BumpPtrAllocator _alloc; - bool _firstTime; -}; - -} // end namespace pecoff -} // end namespace lld |