diff options
Diffstat (limited to 'wasm/Driver.cpp')
| -rw-r--r-- | wasm/Driver.cpp | 619 |
1 files changed, 0 insertions, 619 deletions
diff --git a/wasm/Driver.cpp b/wasm/Driver.cpp deleted file mode 100644 index fab4c0c4ed8b..000000000000 --- a/wasm/Driver.cpp +++ /dev/null @@ -1,619 +0,0 @@ -//===- Driver.cpp ---------------------------------------------------------===// -// -// The LLVM Linker -// -// This file is distributed under the University of Illinois Open Source -// License. See LICENSE.TXT for details. -// -//===----------------------------------------------------------------------===// - -#include "lld/Common/Driver.h" -#include "Config.h" -#include "InputChunks.h" -#include "InputGlobal.h" -#include "MarkLive.h" -#include "SymbolTable.h" -#include "Writer.h" -#include "lld/Common/Args.h" -#include "lld/Common/ErrorHandler.h" -#include "lld/Common/Memory.h" -#include "lld/Common/Strings.h" -#include "lld/Common/Threads.h" -#include "lld/Common/Version.h" -#include "llvm/ADT/Twine.h" -#include "llvm/Object/Wasm.h" -#include "llvm/Option/ArgList.h" -#include "llvm/Support/CommandLine.h" -#include "llvm/Support/Path.h" -#include "llvm/Support/Process.h" -#include "llvm/Support/TargetSelect.h" - -#define DEBUG_TYPE "lld" - -using namespace llvm; -using namespace llvm::object; -using namespace llvm::sys; -using namespace llvm::wasm; - -using namespace lld; -using namespace lld::wasm; - -Configuration *lld::wasm::Config; - -namespace { - -// Create enum with OPT_xxx values for each option in Options.td -enum { - OPT_INVALID = 0, -#define OPTION(_1, _2, ID, _4, _5, _6, _7, _8, _9, _10, _11, _12) OPT_##ID, -#include "Options.inc" -#undef OPTION -}; - -// This function is called on startup. We need this for LTO since -// LTO calls LLVM functions to compile bitcode files to native code. -// Technically this can be delayed until we read bitcode files, but -// we don't bother to do lazily because the initialization is fast. -static void initLLVM() { - InitializeAllTargets(); - InitializeAllTargetMCs(); - InitializeAllAsmPrinters(); - InitializeAllAsmParsers(); -} - -class LinkerDriver { -public: - void link(ArrayRef<const char *> ArgsArr); - -private: - void createFiles(opt::InputArgList &Args); - void addFile(StringRef Path); - void addLibrary(StringRef Name); - - // True if we are in --whole-archive and --no-whole-archive. - bool InWholeArchive = false; - - std::vector<InputFile *> Files; -}; -} // anonymous namespace - -bool lld::wasm::link(ArrayRef<const char *> Args, bool CanExitEarly, - raw_ostream &Error) { - errorHandler().LogName = args::getFilenameWithoutExe(Args[0]); - errorHandler().ErrorOS = &Error; - errorHandler().ColorDiagnostics = Error.has_colors(); - errorHandler().ErrorLimitExceededMsg = - "too many errors emitted, stopping now (use " - "-error-limit=0 to see all errors)"; - - Config = make<Configuration>(); - Symtab = make<SymbolTable>(); - - initLLVM(); - LinkerDriver().link(Args); - - // Exit immediately if we don't need to return to the caller. - // This saves time because the overhead of calling destructors - // for all globally-allocated objects is not negligible. - if (CanExitEarly) - exitLld(errorCount() ? 1 : 0); - - freeArena(); - return !errorCount(); -} - -// Create prefix string literals used in Options.td -#define PREFIX(NAME, VALUE) const char *const NAME[] = VALUE; -#include "Options.inc" -#undef PREFIX - -// Create table mapping all options defined in Options.td -static const opt::OptTable::Info OptInfo[] = { -#define OPTION(X1, X2, ID, KIND, GROUP, ALIAS, X7, X8, X9, X10, X11, X12) \ - {X1, X2, X10, X11, OPT_##ID, opt::Option::KIND##Class, \ - X9, X8, OPT_##GROUP, OPT_##ALIAS, X7, X12}, -#include "Options.inc" -#undef OPTION -}; - -namespace { -class WasmOptTable : public llvm::opt::OptTable { -public: - WasmOptTable() : OptTable(OptInfo) {} - opt::InputArgList parse(ArrayRef<const char *> Argv); -}; -} // namespace - -// Set color diagnostics according to -color-diagnostics={auto,always,never} -// or -no-color-diagnostics flags. -static void handleColorDiagnostics(opt::InputArgList &Args) { - auto *Arg = Args.getLastArg(OPT_color_diagnostics, OPT_color_diagnostics_eq, - OPT_no_color_diagnostics); - if (!Arg) - return; - if (Arg->getOption().getID() == OPT_color_diagnostics) { - errorHandler().ColorDiagnostics = true; - } else if (Arg->getOption().getID() == OPT_no_color_diagnostics) { - errorHandler().ColorDiagnostics = false; - } else { - StringRef S = Arg->getValue(); - if (S == "always") - errorHandler().ColorDiagnostics = true; - else if (S == "never") - errorHandler().ColorDiagnostics = false; - else if (S != "auto") - error("unknown option: --color-diagnostics=" + S); - } -} - -// Find a file by concatenating given paths. -static Optional<std::string> findFile(StringRef Path1, const Twine &Path2) { - SmallString<128> S; - path::append(S, Path1, Path2); - if (fs::exists(S)) - return S.str().str(); - return None; -} - -opt::InputArgList WasmOptTable::parse(ArrayRef<const char *> Argv) { - SmallVector<const char *, 256> Vec(Argv.data(), Argv.data() + Argv.size()); - - unsigned MissingIndex; - unsigned MissingCount; - - // Expand response files (arguments in the form of @<filename>) - cl::ExpandResponseFiles(Saver, cl::TokenizeGNUCommandLine, Vec); - - opt::InputArgList Args = this->ParseArgs(Vec, MissingIndex, MissingCount); - - handleColorDiagnostics(Args); - for (auto *Arg : Args.filtered(OPT_UNKNOWN)) - error("unknown argument: " + Arg->getSpelling()); - return Args; -} - -// Currently we allow a ".imports" to live alongside a library. This can -// be used to specify a list of symbols which can be undefined at link -// time (imported from the environment. For example libc.a include an -// import file that lists the syscall functions it relies on at runtime. -// In the long run this information would be better stored as a symbol -// attribute/flag in the object file itself. -// See: https://github.com/WebAssembly/tool-conventions/issues/35 -static void readImportFile(StringRef Filename) { - if (Optional<MemoryBufferRef> Buf = readFile(Filename)) - for (StringRef Sym : args::getLines(*Buf)) - Config->AllowUndefinedSymbols.insert(Sym); -} - -// Returns slices of MB by parsing MB as an archive file. -// Each slice consists of a member file in the archive. -std::vector<MemoryBufferRef> static getArchiveMembers(MemoryBufferRef MB) { - std::unique_ptr<Archive> File = - CHECK(Archive::create(MB), - MB.getBufferIdentifier() + ": failed to parse archive"); - - std::vector<MemoryBufferRef> V; - Error Err = Error::success(); - for (const ErrorOr<Archive::Child> &COrErr : File->children(Err)) { - Archive::Child C = - CHECK(COrErr, MB.getBufferIdentifier() + - ": could not get the child of the archive"); - MemoryBufferRef MBRef = - CHECK(C.getMemoryBufferRef(), - MB.getBufferIdentifier() + - ": could not get the buffer for a child of the archive"); - V.push_back(MBRef); - } - if (Err) - fatal(MB.getBufferIdentifier() + - ": Archive::children failed: " + toString(std::move(Err))); - - // Take ownership of memory buffers created for members of thin archives. - for (std::unique_ptr<MemoryBuffer> &MB : File->takeThinBuffers()) - make<std::unique_ptr<MemoryBuffer>>(std::move(MB)); - - return V; -} - -void LinkerDriver::addFile(StringRef Path) { - Optional<MemoryBufferRef> Buffer = readFile(Path); - if (!Buffer.hasValue()) - return; - MemoryBufferRef MBRef = *Buffer; - - switch (identify_magic(MBRef.getBuffer())) { - case file_magic::archive: { - // Handle -whole-archive. - if (InWholeArchive) { - for (MemoryBufferRef &M : getArchiveMembers(MBRef)) - Files.push_back(createObjectFile(M)); - return; - } - - SmallString<128> ImportFile = Path; - path::replace_extension(ImportFile, ".imports"); - if (fs::exists(ImportFile)) - readImportFile(ImportFile.str()); - - Files.push_back(make<ArchiveFile>(MBRef)); - return; - } - case file_magic::bitcode: - case file_magic::wasm_object: - Files.push_back(createObjectFile(MBRef)); - break; - default: - error("unknown file type: " + MBRef.getBufferIdentifier()); - } -} - -// Add a given library by searching it from input search paths. -void LinkerDriver::addLibrary(StringRef Name) { - for (StringRef Dir : Config->SearchPaths) { - if (Optional<std::string> S = findFile(Dir, "lib" + Name + ".a")) { - addFile(*S); - return; - } - } - - error("unable to find library -l" + Name); -} - -void LinkerDriver::createFiles(opt::InputArgList &Args) { - for (auto *Arg : Args) { - switch (Arg->getOption().getUnaliasedOption().getID()) { - case OPT_l: - addLibrary(Arg->getValue()); - break; - case OPT_INPUT: - addFile(Arg->getValue()); - break; - case OPT_whole_archive: - InWholeArchive = true; - break; - case OPT_no_whole_archive: - InWholeArchive = false; - break; - } - } -} - -static StringRef getEntry(opt::InputArgList &Args, StringRef Default) { - auto *Arg = Args.getLastArg(OPT_entry, OPT_no_entry); - if (!Arg) - return Default; - if (Arg->getOption().getID() == OPT_no_entry) - return ""; - return Arg->getValue(); -} - -static const uint8_t UnreachableFn[] = { - 0x03 /* ULEB length */, 0x00 /* ULEB num locals */, - 0x00 /* opcode unreachable */, 0x0b /* opcode end */ -}; - -// For weak undefined functions, there may be "call" instructions that reference -// the symbol. In this case, we need to synthesise a dummy/stub function that -// will abort at runtime, so that relocations can still provided an operand to -// the call instruction that passes Wasm validation. -static void handleWeakUndefines() { - for (Symbol *Sym : Symtab->getSymbols()) { - if (!Sym->isUndefined() || !Sym->isWeak()) - continue; - auto *FuncSym = dyn_cast<FunctionSymbol>(Sym); - if (!FuncSym) - continue; - - // It is possible for undefined functions not to have a signature (eg. if - // added via "--undefined"), but weak undefined ones do have a signature. - assert(FuncSym->Signature); - const WasmSignature &Sig = *FuncSym->Signature; - - // Add a synthetic dummy for weak undefined functions. These dummies will - // be GC'd if not used as the target of any "call" instructions. - std::string SymName = toString(*Sym); - StringRef DebugName = Saver.save("undefined function " + SymName); - auto *Func = make<SyntheticFunction>(Sig, Sym->getName(), DebugName); - Func->setBody(UnreachableFn); - // Ensure it compares equal to the null pointer, and so that table relocs - // don't pull in the stub body (only call-operand relocs should do that). - Func->setTableIndex(0); - Symtab->SyntheticFunctions.emplace_back(Func); - // Hide our dummy to prevent export. - uint32_t Flags = WASM_SYMBOL_VISIBILITY_HIDDEN; - replaceSymbol<DefinedFunction>(Sym, Sym->getName(), Flags, nullptr, Func); - } -} - -// Some Config members do not directly correspond to any particular -// command line options, but computed based on other Config values. -// This function initialize such members. See Config.h for the details -// of these values. -static void setConfigs(opt::InputArgList &Args) { - Config->AllowUndefined = Args.hasArg(OPT_allow_undefined); - Config->CompressRelocations = Args.hasArg(OPT_compress_relocations); - Config->Demangle = Args.hasFlag(OPT_demangle, OPT_no_demangle, true); - Config->DisableVerify = Args.hasArg(OPT_disable_verify); - Config->Entry = getEntry(Args, Args.hasArg(OPT_relocatable) ? "" : "_start"); - Config->ExportAll = Args.hasArg(OPT_export_all); - Config->ExportDynamic = Args.hasFlag(OPT_export_dynamic, - OPT_no_export_dynamic, false); - Config->ExportTable = Args.hasArg(OPT_export_table); - errorHandler().FatalWarnings = - Args.hasFlag(OPT_fatal_warnings, OPT_no_fatal_warnings, false); - Config->ImportMemory = Args.hasArg(OPT_import_memory); - Config->SharedMemory = Args.hasArg(OPT_shared_memory); - Config->ImportTable = Args.hasArg(OPT_import_table); - Config->LTOO = args::getInteger(Args, OPT_lto_O, 2); - Config->LTOPartitions = args::getInteger(Args, OPT_lto_partitions, 1); - Config->Optimize = args::getInteger(Args, OPT_O, 0); - Config->OutputFile = Args.getLastArgValue(OPT_o); - Config->Relocatable = Args.hasArg(OPT_relocatable); - Config->GcSections = - Args.hasFlag(OPT_gc_sections, OPT_no_gc_sections, !Config->Relocatable); - Config->MergeDataSegments = - Args.hasFlag(OPT_merge_data_segments, OPT_no_merge_data_segments, - !Config->Relocatable); - Config->Pie = Args.hasFlag(OPT_pie, OPT_no_pie, false); - Config->PrintGcSections = - Args.hasFlag(OPT_print_gc_sections, OPT_no_print_gc_sections, false); - Config->SaveTemps = Args.hasArg(OPT_save_temps); - Config->SearchPaths = args::getStrings(Args, OPT_L); - Config->Shared = Args.hasArg(OPT_shared); - Config->StripAll = Args.hasArg(OPT_strip_all); - Config->StripDebug = Args.hasArg(OPT_strip_debug); - Config->StackFirst = Args.hasArg(OPT_stack_first); - Config->ThinLTOCacheDir = Args.getLastArgValue(OPT_thinlto_cache_dir); - Config->ThinLTOCachePolicy = CHECK( - parseCachePruningPolicy(Args.getLastArgValue(OPT_thinlto_cache_policy)), - "--thinlto-cache-policy: invalid cache policy"); - Config->ThinLTOJobs = args::getInteger(Args, OPT_thinlto_jobs, -1u); - errorHandler().Verbose = Args.hasArg(OPT_verbose); - ThreadsEnabled = Args.hasFlag(OPT_threads, OPT_no_threads, true); - - Config->InitialMemory = args::getInteger(Args, OPT_initial_memory, 0); - Config->GlobalBase = args::getInteger(Args, OPT_global_base, 1024); - Config->MaxMemory = args::getInteger(Args, OPT_max_memory, 0); - Config->ZStackSize = - args::getZOptionValue(Args, OPT_z, "stack-size", WasmPageSize); -} - -// Some command line options or some combinations of them are not allowed. -// This function checks for such errors. -static void checkOptions(opt::InputArgList &Args) { - if (!Config->StripDebug && !Config->StripAll && Config->CompressRelocations) - error("--compress-relocations is incompatible with output debug" - " information. Please pass --strip-debug or --strip-all"); - - if (Config->LTOO > 3) - error("invalid optimization level for LTO: " + Twine(Config->LTOO)); - if (Config->LTOPartitions == 0) - error("--lto-partitions: number of threads must be > 0"); - if (Config->ThinLTOJobs == 0) - error("--thinlto-jobs: number of threads must be > 0"); - - if (Config->Pie && Config->Shared) - error("-shared and -pie may not be used together"); - - if (Config->OutputFile.empty()) - error("no output file specified"); - - if (Config->ImportTable && Config->ExportTable) - error("--import-table and --export-table may not be used together"); - - if (Config->Relocatable) { - if (!Config->Entry.empty()) - error("entry point specified for relocatable output file"); - if (Config->GcSections) - error("-r and --gc-sections may not be used together"); - if (Config->CompressRelocations) - error("-r -and --compress-relocations may not be used together"); - if (Args.hasArg(OPT_undefined)) - error("-r -and --undefined may not be used together"); - if (Config->Pie) - error("-r and -pie may not be used together"); - } -} - -// Force Sym to be entered in the output. Used for -u or equivalent. -static Symbol *handleUndefined(StringRef Name) { - Symbol *Sym = Symtab->find(Name); - if (!Sym) - return nullptr; - - // Since symbol S may not be used inside the program, LTO may - // eliminate it. Mark the symbol as "used" to prevent it. - Sym->IsUsedInRegularObj = true; - - if (auto *LazySym = dyn_cast<LazySymbol>(Sym)) - LazySym->fetch(); - - return Sym; -} - -static UndefinedGlobal * -createUndefinedGlobal(StringRef Name, llvm::wasm::WasmGlobalType *Type) { - auto *Sym = - cast<UndefinedGlobal>(Symtab->addUndefinedGlobal(Name, 0, nullptr, Type)); - Config->AllowUndefinedSymbols.insert(Sym->getName()); - Sym->IsUsedInRegularObj = true; - return Sym; -} - -// Create ABI-defined synthetic symbols -static void createSyntheticSymbols() { - static WasmSignature NullSignature = {{}, {}}; - static llvm::wasm::WasmGlobalType GlobalTypeI32 = {WASM_TYPE_I32, false}; - static llvm::wasm::WasmGlobalType MutableGlobalTypeI32 = {WASM_TYPE_I32, - true}; - - if (!Config->Relocatable) - WasmSym::CallCtors = Symtab->addSyntheticFunction( - "__wasm_call_ctors", WASM_SYMBOL_VISIBILITY_HIDDEN, - make<SyntheticFunction>(NullSignature, "__wasm_call_ctors")); - - // The __stack_pointer is imported in the shared library case, and exported - // in the non-shared (executable) case. - if (Config->Shared) { - WasmSym::StackPointer = - createUndefinedGlobal("__stack_pointer", &MutableGlobalTypeI32); - } else { - llvm::wasm::WasmGlobal Global; - Global.Type = {WASM_TYPE_I32, true}; - Global.InitExpr.Value.Int32 = 0; - Global.InitExpr.Opcode = WASM_OPCODE_I32_CONST; - Global.SymbolName = "__stack_pointer"; - auto *StackPointer = make<InputGlobal>(Global, nullptr); - StackPointer->Live = true; - // For non-PIC code - // TODO(sbc): Remove WASM_SYMBOL_VISIBILITY_HIDDEN when the mutable global - // spec proposal is implemented in all major browsers. - // See: https://github.com/WebAssembly/mutable-global - WasmSym::StackPointer = Symtab->addSyntheticGlobal( - "__stack_pointer", WASM_SYMBOL_VISIBILITY_HIDDEN, StackPointer); - WasmSym::HeapBase = Symtab->addSyntheticDataSymbol("__heap_base", 0); - WasmSym::DataEnd = Symtab->addSyntheticDataSymbol("__data_end", 0); - - // These two synthetic symbols exist purely for the embedder so we always - // want to export them. - WasmSym::HeapBase->ForceExport = true; - WasmSym::DataEnd->ForceExport = true; - } - - if (Config->Pic) { - // For PIC code, we import two global variables (__memory_base and - // __table_base) from the environment and use these as the offset at - // which to load our static data and function table. - // See: - // https://github.com/WebAssembly/tool-conventions/blob/master/DynamicLinking.md - WasmSym::MemoryBase = - createUndefinedGlobal("__memory_base", &GlobalTypeI32); - WasmSym::TableBase = createUndefinedGlobal("__table_base", &GlobalTypeI32); - WasmSym::MemoryBase->markLive(); - WasmSym::TableBase->markLive(); - } - - WasmSym::DsoHandle = Symtab->addSyntheticDataSymbol( - "__dso_handle", WASM_SYMBOL_VISIBILITY_HIDDEN); -} - -void LinkerDriver::link(ArrayRef<const char *> ArgsArr) { - WasmOptTable Parser; - opt::InputArgList Args = Parser.parse(ArgsArr.slice(1)); - - // Handle --help - if (Args.hasArg(OPT_help)) { - Parser.PrintHelp(outs(), - (std::string(ArgsArr[0]) + " [options] file...").c_str(), - "LLVM Linker", false); - return; - } - - // Handle --version - if (Args.hasArg(OPT_version) || Args.hasArg(OPT_v)) { - outs() << getLLDVersion() << "\n"; - return; - } - - // Parse and evaluate -mllvm options. - std::vector<const char *> V; - V.push_back("wasm-ld (LLVM option parsing)"); - for (auto *Arg : Args.filtered(OPT_mllvm)) - V.push_back(Arg->getValue()); - cl::ParseCommandLineOptions(V.size(), V.data()); - - errorHandler().ErrorLimit = args::getInteger(Args, OPT_error_limit, 20); - - setConfigs(Args); - checkOptions(Args); - - if (auto *Arg = Args.getLastArg(OPT_allow_undefined_file)) - readImportFile(Arg->getValue()); - - if (!Args.hasArg(OPT_INPUT)) { - error("no input files"); - return; - } - - Config->Pic = Config->Pie || Config->Shared; - - if (Config->Pic) { - if (Config->ExportTable) - error("-shared/-pie is incompatible with --export-table"); - Config->ImportTable = true; - } - - if (Config->Shared) { - Config->ExportDynamic = true; - Config->AllowUndefined = true; - } - - if (!Config->Relocatable) - createSyntheticSymbols(); - - createFiles(Args); - if (errorCount()) - return; - - // Add all files to the symbol table. This will add almost all - // symbols that we need to the symbol table. - for (InputFile *F : Files) - Symtab->addFile(F); - if (errorCount()) - return; - - // Handle the `--undefined <sym>` options. - for (auto *Arg : Args.filtered(OPT_undefined)) - handleUndefined(Arg->getValue()); - - // Handle the `--export <sym>` options - // This works like --undefined but also exports the symbol if its found - for (auto *Arg : Args.filtered(OPT_export)) { - Symbol *Sym = handleUndefined(Arg->getValue()); - if (Sym && Sym->isDefined()) - Sym->ForceExport = true; - else if (!Config->AllowUndefined) - error(Twine("symbol exported via --export not found: ") + - Arg->getValue()); - } - - Symbol *EntrySym = nullptr; - if (!Config->Relocatable) { - // Add synthetic dummies for weak undefined functions. - handleWeakUndefines(); - - if (!Config->Shared && !Config->Entry.empty()) { - EntrySym = handleUndefined(Config->Entry); - if (EntrySym && EntrySym->isDefined()) - EntrySym->ForceExport = true; - else - error("entry symbol not defined (pass --no-entry to supress): " + - Config->Entry); - } - - // Make sure we have resolved all symbols. - if (!Config->AllowUndefined) - Symtab->reportRemainingUndefines(); - } - - if (errorCount()) - return; - - // Do link-time optimization if given files are LLVM bitcode files. - // This compiles bitcode files into real object files. - Symtab->addCombinedLTOObject(); - if (errorCount()) - return; - - if (EntrySym) - EntrySym->setHidden(false); - - if (errorCount()) - return; - - // Do size optimizations: garbage collection - markLive(); - - // Write the result to the file. - writeResult(); -} |