diff options
Diffstat (limited to 'tools/gold/gold-plugin.cpp')
| -rw-r--r-- | tools/gold/gold-plugin.cpp | 782 |
1 files changed, 560 insertions, 222 deletions
diff --git a/tools/gold/gold-plugin.cpp b/tools/gold/gold-plugin.cpp index b908510..cfda6d2 100644 --- a/tools/gold/gold-plugin.cpp +++ b/tools/gold/gold-plugin.cpp @@ -13,33 +13,35 @@ //===----------------------------------------------------------------------===// #include "llvm/Config/config.h" // plugin-api.h requires HAVE_STDINT_H -#include "llvm-c/lto.h" +#include "llvm/ADT/DenseSet.h" #include "llvm/ADT/StringSet.h" +#include "llvm/Bitcode/ReaderWriter.h" +#include "llvm/CodeGen/Analysis.h" #include "llvm/CodeGen/CommandFlags.h" -#include "llvm/LTO/LTOCodeGenerator.h" -#include "llvm/LTO/LTOModule.h" -#include "llvm/Support/Errno.h" -#include "llvm/Support/FileSystem.h" +#include "llvm/IR/Constants.h" +#include "llvm/IR/LLVMContext.h" +#include "llvm/IR/Module.h" +#include "llvm/IR/Verifier.h" +#include "llvm/Linker/Linker.h" +#include "llvm/MC/SubtargetFeature.h" +#include "llvm/Object/IRObjectFile.h" +#include "llvm/PassManager.h" +#include "llvm/Support/FormattedStream.h" +#include "llvm/Support/Host.h" #include "llvm/Support/MemoryBuffer.h" -#include "llvm/Support/Path.h" -#include "llvm/Support/Program.h" +#include "llvm/Support/TargetRegistry.h" #include "llvm/Support/TargetSelect.h" -#include "llvm/Support/ToolOutputFile.h" -#include <cerrno> -#include <cstdlib> -#include <cstring> +#include "llvm/Target/TargetLibraryInfo.h" +#include "llvm/Transforms/IPO.h" +#include "llvm/Transforms/IPO/PassManagerBuilder.h" +#include "llvm/Transforms/Utils/GlobalStatus.h" +#include "llvm/Transforms/Utils/ModuleUtils.h" +#include "llvm/Transforms/Utils/ValueMapper.h" #include <list> #include <plugin-api.h> #include <system_error> #include <vector> -// Support Windows/MinGW crazyness. -#ifdef _WIN32 -# include <io.h> -# define lseek _lseek -# define read _read -#endif - #ifndef LDPO_PIE // FIXME: remove this declaration when we stop maintaining Ubuntu Quantal and // Precise and Debian Wheezy (binutils 2.23 is required) @@ -61,25 +63,24 @@ static ld_plugin_status discard_message(int level, const char *format, ...) { abort(); } -static ld_plugin_add_symbols add_symbols = NULL; -static ld_plugin_get_symbols get_symbols = NULL; -static ld_plugin_add_input_file add_input_file = NULL; -static ld_plugin_set_extra_library_path set_extra_library_path = NULL; -static ld_plugin_get_view get_view = NULL; +static ld_plugin_get_input_file get_input_file = nullptr; +static ld_plugin_release_input_file release_input_file = nullptr; +static ld_plugin_add_symbols add_symbols = nullptr; +static ld_plugin_get_symbols get_symbols = nullptr; +static ld_plugin_add_input_file add_input_file = nullptr; +static ld_plugin_set_extra_library_path set_extra_library_path = nullptr; +static ld_plugin_get_view get_view = nullptr; static ld_plugin_message message = discard_message; -static lto_codegen_model output_type = LTO_CODEGEN_PIC_MODEL_STATIC; +static Reloc::Model RelocationModel = Reloc::Default; static std::string output_name = ""; static std::list<claimed_file> Modules; static std::vector<std::string> Cleanup; -static LTOCodeGenerator *CodeGen = nullptr; -static StringSet<> CannotBeHidden; static llvm::TargetOptions TargetOpts; namespace options { - enum generate_bc { BC_NO, BC_ALSO, BC_ONLY }; + enum generate_bc { BC_NO, BC_ONLY, BC_SAVE_TEMPS }; static bool generate_api_file = false; static generate_bc generate_bc_file = BC_NO; - static std::string bc_path; static std::string obj_path; static std::string extra_library_path; static std::string triple; @@ -89,11 +90,11 @@ namespace options { // as plugin exclusive to pass to the code generator. // For example, "generate-api-file" and "as"options are for the plugin // use only and will not be passed. - static std::vector<std::string> extra; + static std::vector<const char *> extra; static void process_plugin_option(const char* opt_) { - if (opt_ == NULL) + if (opt_ == nullptr) return; llvm::StringRef opt = opt_; @@ -109,20 +110,16 @@ namespace options { obj_path = opt.substr(strlen("obj-path=")); } else if (opt == "emit-llvm") { generate_bc_file = BC_ONLY; - } else if (opt == "also-emit-llvm") { - generate_bc_file = BC_ALSO; - } else if (opt.startswith("also-emit-llvm=")) { - llvm::StringRef path = opt.substr(strlen("also-emit-llvm=")); - generate_bc_file = BC_ALSO; - if (!bc_path.empty()) { - (*message)(LDPL_WARNING, "Path to the output IL file specified twice. " - "Discarding %s", opt_); - } else { - bc_path = path; - } + } else if (opt == "save-temps") { + generate_bc_file = BC_SAVE_TEMPS; } else { // Save this option to pass to the code generator. - extra.push_back(opt); + // ParseCommandLineOptions() expects argv[0] to be program name. Lazily + // add that. + if (extra.empty()) + extra.push_back("LLVMgold"); + + extra.push_back(opt_); } } } @@ -159,14 +156,13 @@ ld_plugin_status onload(ld_plugin_tv *tv) { case LDPO_REL: // .o case LDPO_DYN: // .so case LDPO_PIE: // position independent executable - output_type = LTO_CODEGEN_PIC_MODEL_DYNAMIC; + RelocationModel = Reloc::PIC_; break; case LDPO_EXEC: // .exe - output_type = LTO_CODEGEN_PIC_MODEL_STATIC; + RelocationModel = Reloc::Static; break; default: - (*message)(LDPL_ERROR, "Unknown output file type %d", - tv->tv_u.tv_val); + message(LDPL_ERROR, "Unknown output file type %d", tv->tv_u.tv_val); return LDPS_ERR; } break; @@ -177,7 +173,7 @@ ld_plugin_status onload(ld_plugin_tv *tv) { ld_plugin_register_claim_file callback; callback = tv->tv_u.tv_register_claim_file; - if ((*callback)(claim_file_hook) != LDPS_OK) + if (callback(claim_file_hook) != LDPS_OK) return LDPS_ERR; registeredClaimFile = true; @@ -186,7 +182,7 @@ ld_plugin_status onload(ld_plugin_tv *tv) { ld_plugin_register_all_symbols_read callback; callback = tv->tv_u.tv_register_all_symbols_read; - if ((*callback)(all_symbols_read_hook) != LDPS_OK) + if (callback(all_symbols_read_hook) != LDPS_OK) return LDPS_ERR; RegisteredAllSymbolsRead = true; @@ -195,9 +191,15 @@ ld_plugin_status onload(ld_plugin_tv *tv) { ld_plugin_register_cleanup callback; callback = tv->tv_u.tv_register_cleanup; - if ((*callback)(cleanup_hook) != LDPS_OK) + if (callback(cleanup_hook) != LDPS_OK) return LDPS_ERR; } break; + case LDPT_GET_INPUT_FILE: + get_input_file = tv->tv_u.tv_get_input_file; + break; + case LDPT_RELEASE_INPUT_FILE: + release_input_file = tv->tv_u.tv_release_input_file; + break; case LDPT_ADD_SYMBOLS: add_symbols = tv->tv_u.tv_add_symbols; break; @@ -222,56 +224,50 @@ ld_plugin_status onload(ld_plugin_tv *tv) { } if (!registeredClaimFile) { - (*message)(LDPL_ERROR, "register_claim_file not passed to LLVMgold."); + message(LDPL_ERROR, "register_claim_file not passed to LLVMgold."); return LDPS_ERR; } if (!add_symbols) { - (*message)(LDPL_ERROR, "add_symbols not passed to LLVMgold."); + message(LDPL_ERROR, "add_symbols not passed to LLVMgold."); return LDPS_ERR; } if (!RegisteredAllSymbolsRead) return LDPS_OK; - CodeGen = new LTOCodeGenerator(); - - // Pass through extra options to the code generator. - if (!options::extra.empty()) { - for (std::vector<std::string>::iterator it = options::extra.begin(); - it != options::extra.end(); ++it) { - CodeGen->setCodeGenDebugOptions((*it).c_str()); - } + if (!get_input_file) { + message(LDPL_ERROR, "get_input_file not passed to LLVMgold."); + return LDPS_ERR; } - - CodeGen->parseCodeGenDebugOptions(); - if (MAttrs.size()) { - std::string Attrs; - for (unsigned I = 0; I < MAttrs.size(); ++I) { - if (I > 0) - Attrs.append(","); - Attrs.append(MAttrs[I]); - } - CodeGen->setAttr(Attrs.c_str()); + if (!release_input_file) { + message(LDPL_ERROR, "relesase_input_file not passed to LLVMgold."); + return LDPS_ERR; } - TargetOpts = InitTargetOptionsFromCodeGenFlags(); - CodeGen->setTargetOptions(TargetOpts); - return LDPS_OK; } +static const GlobalObject *getBaseObject(const GlobalValue &GV) { + if (auto *GA = dyn_cast<GlobalAlias>(&GV)) + return GA->getBaseObject(); + return cast<GlobalObject>(&GV); +} + /// Called by gold to see whether this file is one that our plugin can handle. /// We'll try to open it and register all the symbols with add_symbol if /// possible. static ld_plugin_status claim_file_hook(const ld_plugin_input_file *file, int *claimed) { - const void *view; - std::unique_ptr<MemoryBuffer> buffer; + LLVMContext Context; + MemoryBufferRef BufferRef; + std::unique_ptr<MemoryBuffer> Buffer; if (get_view) { + const void *view; if (get_view(file->handle, &view) != LDPS_OK) { - (*message)(LDPL_ERROR, "Failed to get a view of %s", file->name); + message(LDPL_ERROR, "Failed to get a view of %s", file->name); return LDPS_ERR; } + BufferRef = MemoryBufferRef(StringRef((const char *)view, file->filesize), ""); } else { int64_t offset = 0; // Gold has found what might be IR part-way inside of a file, such as @@ -283,225 +279,567 @@ static ld_plugin_status claim_file_hook(const ld_plugin_input_file *file, MemoryBuffer::getOpenFileSlice(file->fd, file->name, file->filesize, offset); if (std::error_code EC = BufferOrErr.getError()) { - (*message)(LDPL_ERROR, EC.message().c_str()); + message(LDPL_ERROR, EC.message().c_str()); return LDPS_ERR; } - buffer = std::move(BufferOrErr.get()); - view = buffer->getBufferStart(); + Buffer = std::move(BufferOrErr.get()); + BufferRef = Buffer->getMemBufferRef(); } - if (!LTOModule::isBitcodeFile(view, file->filesize)) + ErrorOr<std::unique_ptr<object::IRObjectFile>> ObjOrErr = + object::IRObjectFile::createIRObjectFile(BufferRef, Context); + std::error_code EC = ObjOrErr.getError(); + if (EC == BitcodeError::InvalidBitcodeSignature || + EC == object::object_error::invalid_file_type || + EC == object::object_error::bitcode_section_not_found) return LDPS_OK; - std::string Error; - LTOModule *M = - LTOModule::createFromBuffer(view, file->filesize, TargetOpts, Error); - if (!M) { - (*message)(LDPL_ERROR, - "LLVM gold plugin has failed to create LTO module: %s", - Error.c_str()); - return LDPS_OK; + *claimed = 1; + + if (EC) { + message(LDPL_ERROR, "LLVM gold plugin has failed to create LTO module: %s", + EC.message().c_str()); + return LDPS_ERR; } + std::unique_ptr<object::IRObjectFile> Obj = std::move(*ObjOrErr); - *claimed = 1; Modules.resize(Modules.size() + 1); claimed_file &cf = Modules.back(); - if (!options::triple.empty()) - M->setTargetTriple(options::triple.c_str()); - cf.handle = file->handle; - unsigned sym_count = M->getSymbolCount(); - cf.syms.reserve(sym_count); - for (unsigned i = 0; i != sym_count; ++i) { - lto_symbol_attributes attrs = M->getSymbolAttributes(i); - if ((attrs & LTO_SYMBOL_SCOPE_MASK) == LTO_SYMBOL_SCOPE_INTERNAL) + for (auto &Sym : Obj->symbols()) { + uint32_t Symflags = Sym.getFlags(); + if (!(Symflags & object::BasicSymbolRef::SF_Global)) + continue; + + if (Symflags & object::BasicSymbolRef::SF_FormatSpecific) continue; cf.syms.push_back(ld_plugin_symbol()); ld_plugin_symbol &sym = cf.syms.back(); - sym.name = strdup(M->getSymbolName(i)); - sym.version = NULL; - - int scope = attrs & LTO_SYMBOL_SCOPE_MASK; - bool CanBeHidden = scope == LTO_SYMBOL_SCOPE_DEFAULT_CAN_BE_HIDDEN; - if (!CanBeHidden) - CannotBeHidden.insert(sym.name); - switch (scope) { - case LTO_SYMBOL_SCOPE_HIDDEN: + sym.version = nullptr; + + SmallString<64> Name; + { + raw_svector_ostream OS(Name); + Sym.printName(OS); + } + sym.name = strdup(Name.c_str()); + + const GlobalValue *GV = Obj->getSymbolGV(Sym.getRawDataRefImpl()); + + sym.visibility = LDPV_DEFAULT; + if (GV) { + switch (GV->getVisibility()) { + case GlobalValue::DefaultVisibility: + sym.visibility = LDPV_DEFAULT; + break; + case GlobalValue::HiddenVisibility: sym.visibility = LDPV_HIDDEN; break; - case LTO_SYMBOL_SCOPE_PROTECTED: + case GlobalValue::ProtectedVisibility: sym.visibility = LDPV_PROTECTED; break; - case 0: // extern - case LTO_SYMBOL_SCOPE_DEFAULT: - case LTO_SYMBOL_SCOPE_DEFAULT_CAN_BE_HIDDEN: - sym.visibility = LDPV_DEFAULT; - break; - default: - (*message)(LDPL_ERROR, "Unknown scope attribute: %d", scope); - return LDPS_ERR; + } } - int definition = attrs & LTO_SYMBOL_DEFINITION_MASK; - sym.comdat_key = NULL; - switch (definition) { - case LTO_SYMBOL_DEFINITION_REGULAR: - sym.def = LDPK_DEF; - break; - case LTO_SYMBOL_DEFINITION_UNDEFINED: - sym.def = LDPK_UNDEF; - break; - case LTO_SYMBOL_DEFINITION_TENTATIVE: - sym.def = LDPK_COMMON; - break; - case LTO_SYMBOL_DEFINITION_WEAK: - sym.comdat_key = sym.name; - sym.def = LDPK_WEAKDEF; - break; - case LTO_SYMBOL_DEFINITION_WEAKUNDEF: + if (Symflags & object::BasicSymbolRef::SF_Undefined) { + sym.def = LDPK_UNDEF; + if (GV && GV->hasExternalWeakLinkage()) sym.def = LDPK_WEAKUNDEF; - break; - default: - (*message)(LDPL_ERROR, "Unknown definition attribute: %d", definition); - return LDPS_ERR; + } else { + sym.def = LDPK_DEF; + if (GV) { + assert(!GV->hasExternalWeakLinkage() && + !GV->hasAvailableExternallyLinkage() && "Not a declaration!"); + if (GV->hasCommonLinkage()) + sym.def = LDPK_COMMON; + else if (GV->isWeakForLinker()) + sym.def = LDPK_WEAKDEF; + } } sym.size = 0; + sym.comdat_key = nullptr; + if (GV) { + const GlobalObject *Base = getBaseObject(*GV); + if (!Base) + message(LDPL_FATAL, "Unable to determine comdat of alias!"); + const Comdat *C = Base->getComdat(); + if (C) + sym.comdat_key = strdup(C->getName().str().c_str()); + else if (Base->hasWeakLinkage() || Base->hasLinkOnceLinkage()) + sym.comdat_key = strdup(sym.name); + } sym.resolution = LDPR_UNKNOWN; } - cf.syms.reserve(cf.syms.size()); - if (!cf.syms.empty()) { - if ((*add_symbols)(cf.handle, cf.syms.size(), &cf.syms[0]) != LDPS_OK) { - (*message)(LDPL_ERROR, "Unable to add symbols!"); + if (add_symbols(cf.handle, cf.syms.size(), &cf.syms[0]) != LDPS_OK) { + message(LDPL_ERROR, "Unable to add symbols!"); return LDPS_ERR; } } - if (CodeGen) { - std::string Error; - if (!CodeGen->addModule(M, Error)) { - (*message)(LDPL_ERROR, "Error linking module: %s", Error.c_str()); - return LDPS_ERR; - } + return LDPS_OK; +} + +static void keepGlobalValue(GlobalValue &GV, + std::vector<GlobalAlias *> &KeptAliases) { + assert(!GV.hasLocalLinkage()); + + if (auto *GA = dyn_cast<GlobalAlias>(&GV)) + KeptAliases.push_back(GA); + + switch (GV.getLinkage()) { + default: + break; + case GlobalValue::LinkOnceAnyLinkage: + GV.setLinkage(GlobalValue::WeakAnyLinkage); + break; + case GlobalValue::LinkOnceODRLinkage: + GV.setLinkage(GlobalValue::WeakODRLinkage); + break; } - delete M; + assert(!GV.isDiscardableIfUnused()); +} - return LDPS_OK; +static void internalize(GlobalValue &GV) { + if (GV.isDeclarationForLinker()) + return; // We get here if there is a matching asm definition. + if (!GV.hasLocalLinkage()) + GV.setLinkage(GlobalValue::InternalLinkage); } -static bool mustPreserve(const claimed_file &F, int i) { - if (F.syms[i].resolution == LDPR_PREVAILING_DEF) - return true; - if (F.syms[i].resolution == LDPR_PREVAILING_DEF_IRONLY_EXP) - return CannotBeHidden.count(F.syms[i].name); - return false; +static void drop(GlobalValue &GV) { + if (auto *F = dyn_cast<Function>(&GV)) { + F->deleteBody(); + F->setComdat(nullptr); // Should deleteBody do this? + return; + } + + if (auto *Var = dyn_cast<GlobalVariable>(&GV)) { + Var->setInitializer(nullptr); + Var->setLinkage( + GlobalValue::ExternalLinkage); // Should setInitializer do this? + Var->setComdat(nullptr); // and this? + return; + } + + auto &Alias = cast<GlobalAlias>(GV); + Module &M = *Alias.getParent(); + PointerType &Ty = *cast<PointerType>(Alias.getType()); + GlobalValue::LinkageTypes L = Alias.getLinkage(); + auto *Var = + new GlobalVariable(M, Ty.getElementType(), /*isConstant*/ false, L, + /*Initializer*/ nullptr); + Var->takeName(&Alias); + Alias.replaceAllUsesWith(Var); + Alias.eraseFromParent(); } -/// all_symbols_read_hook - gold informs us that all symbols have been read. -/// At this point, we use get_symbols to see if any of our definitions have -/// been overridden by a native object file. Then, perform optimization and -/// codegen. -static ld_plugin_status all_symbols_read_hook(void) { - // FIXME: raw_fd_ostream should be able to represent an unopened file. - std::unique_ptr<raw_fd_ostream> api_file; +static const char *getResolutionName(ld_plugin_symbol_resolution R) { + switch (R) { + case LDPR_UNKNOWN: + return "UNKNOWN"; + case LDPR_UNDEF: + return "UNDEF"; + case LDPR_PREVAILING_DEF: + return "PREVAILING_DEF"; + case LDPR_PREVAILING_DEF_IRONLY: + return "PREVAILING_DEF_IRONLY"; + case LDPR_PREEMPTED_REG: + return "PREEMPTED_REG"; + case LDPR_PREEMPTED_IR: + return "PREEMPTED_IR"; + case LDPR_RESOLVED_IR: + return "RESOLVED_IR"; + case LDPR_RESOLVED_EXEC: + return "RESOLVED_EXEC"; + case LDPR_RESOLVED_DYN: + return "RESOLVED_DYN"; + case LDPR_PREVAILING_DEF_IRONLY_EXP: + return "PREVAILING_DEF_IRONLY_EXP"; + } + llvm_unreachable("Unknown resolution"); +} - assert(CodeGen); +static GlobalObject *makeInternalReplacement(GlobalObject *GO) { + Module *M = GO->getParent(); + GlobalObject *Ret; + if (auto *F = dyn_cast<Function>(GO)) { + if (F->materialize()) + message(LDPL_FATAL, "LLVM gold plugin has failed to read a function"); + + auto *NewF = Function::Create(F->getFunctionType(), F->getLinkage(), + F->getName(), M); + + ValueToValueMapTy VM; + Function::arg_iterator NewI = NewF->arg_begin(); + for (auto &Arg : F->args()) { + NewI->setName(Arg.getName()); + VM[&Arg] = NewI; + ++NewI; + } - if (options::generate_api_file) { - std::string Error; - api_file.reset(new raw_fd_ostream("apifile.txt", Error, sys::fs::F_None)); - if (!Error.empty()) - (*message)(LDPL_FATAL, "Unable to open apifile.txt for writing: %s", - Error.c_str()); + NewF->getBasicBlockList().splice(NewF->end(), F->getBasicBlockList()); + for (auto &BB : *NewF) { + for (auto &Inst : BB) + RemapInstruction(&Inst, VM, RF_IgnoreMissingEntries); + } + + Ret = NewF; + F->deleteBody(); + } else { + auto *Var = cast<GlobalVariable>(GO); + Ret = new GlobalVariable( + *M, Var->getType()->getElementType(), Var->isConstant(), + Var->getLinkage(), Var->getInitializer(), Var->getName(), + nullptr, Var->getThreadLocalMode(), Var->getType()->getAddressSpace(), + Var->isExternallyInitialized()); + Var->setInitializer(nullptr); } + Ret->copyAttributesFrom(GO); + Ret->setLinkage(GlobalValue::InternalLinkage); + Ret->setComdat(GO->getComdat()); + + return Ret; +} + +namespace { +class LocalValueMaterializer : public ValueMaterializer { + DenseSet<GlobalValue *> &Dropped; + +public: + LocalValueMaterializer(DenseSet<GlobalValue *> &Dropped) : Dropped(Dropped) {} + Value *materializeValueFor(Value *V) override; +}; +} + +Value *LocalValueMaterializer::materializeValueFor(Value *V) { + auto *GV = dyn_cast<GlobalValue>(V); + if (!GV) + return nullptr; + if (!Dropped.count(GV)) + return nullptr; + assert(!isa<GlobalAlias>(GV) && "Found alias point to weak alias."); + return makeInternalReplacement(cast<GlobalObject>(GV)); +} + +static Constant *mapConstantToLocalCopy(Constant *C, ValueToValueMapTy &VM, + LocalValueMaterializer *Materializer) { + return MapValue(C, VM, RF_IgnoreMissingEntries, nullptr, Materializer); +} + +static std::unique_ptr<Module> +getModuleForFile(LLVMContext &Context, claimed_file &F, raw_fd_ostream *ApiFile, + StringSet<> &Internalize, StringSet<> &Maybe) { + ld_plugin_input_file File; + if (get_input_file(F.handle, &File) != LDPS_OK) + message(LDPL_FATAL, "Failed to get file information"); + + if (get_symbols(F.handle, F.syms.size(), &F.syms[0]) != LDPS_OK) + message(LDPL_FATAL, "Failed to get symbol information"); - for (std::list<claimed_file>::iterator I = Modules.begin(), - E = Modules.end(); I != E; ++I) { - if (I->syms.empty()) + const void *View; + if (get_view(F.handle, &View) != LDPS_OK) + message(LDPL_FATAL, "Failed to get a view of file"); + + llvm::ErrorOr<MemoryBufferRef> MBOrErr = + object::IRObjectFile::findBitcodeInMemBuffer( + MemoryBufferRef(StringRef((const char *)View, File.filesize), "")); + if (std::error_code EC = MBOrErr.getError()) + message(LDPL_FATAL, "Could not read bitcode from file : %s", + EC.message().c_str()); + + std::unique_ptr<MemoryBuffer> Buffer = + MemoryBuffer::getMemBuffer(MBOrErr->getBuffer(), "", false); + + if (release_input_file(F.handle) != LDPS_OK) + message(LDPL_FATAL, "Failed to release file information"); + + ErrorOr<Module *> MOrErr = getLazyBitcodeModule(std::move(Buffer), Context); + + if (std::error_code EC = MOrErr.getError()) + message(LDPL_FATAL, "Could not read bitcode from file : %s", + EC.message().c_str()); + + std::unique_ptr<Module> M(MOrErr.get()); + + SmallPtrSet<GlobalValue *, 8> Used; + collectUsedGlobalVariables(*M, Used, /*CompilerUsed*/ false); + + DenseSet<GlobalValue *> Drop; + std::vector<GlobalAlias *> KeptAliases; + for (ld_plugin_symbol &Sym : F.syms) { + ld_plugin_symbol_resolution Resolution = + (ld_plugin_symbol_resolution)Sym.resolution; + + if (options::generate_api_file) + *ApiFile << Sym.name << ' ' << getResolutionName(Resolution) << '\n'; + + GlobalValue *GV = M->getNamedValue(Sym.name); + if (!GV) + continue; // Asm symbol. + + if (Resolution != LDPR_PREVAILING_DEF_IRONLY && GV->hasCommonLinkage()) { + // Common linkage is special. There is no single symbol that wins the + // resolution. Instead we have to collect the maximum alignment and size. + // The IR linker does that for us if we just pass it every common GV. + // We still have to keep track of LDPR_PREVAILING_DEF_IRONLY so we + // internalize once the IR linker has done its job. continue; - (*get_symbols)(I->handle, I->syms.size(), &I->syms[0]); - for (unsigned i = 0, e = I->syms.size(); i != e; i++) { - if (mustPreserve(*I, i)) { - CodeGen->addMustPreserveSymbol(I->syms[i].name); + } - if (options::generate_api_file) - (*api_file) << I->syms[i].name << "\n"; + switch (Resolution) { + case LDPR_UNKNOWN: + llvm_unreachable("Unexpected resolution"); + + case LDPR_RESOLVED_IR: + case LDPR_RESOLVED_EXEC: + case LDPR_RESOLVED_DYN: + case LDPR_UNDEF: + assert(GV->isDeclarationForLinker()); + break; + + case LDPR_PREVAILING_DEF_IRONLY: { + keepGlobalValue(*GV, KeptAliases); + if (!Used.count(GV)) { + // Since we use the regular lib/Linker, we cannot just internalize GV + // now or it will not be copied to the merged module. Instead we force + // it to be copied and then internalize it. + Internalize.insert(Sym.name); } + break; + } + + case LDPR_PREVAILING_DEF: + keepGlobalValue(*GV, KeptAliases); + break; + + case LDPR_PREEMPTED_IR: + // Gold might have selected a linkonce_odr and preempted a weak_odr. + // In that case we have to make sure we don't end up internalizing it. + if (!GV->isDiscardableIfUnused()) + Maybe.erase(Sym.name); + + // fall-through + case LDPR_PREEMPTED_REG: + Drop.insert(GV); + break; + + case LDPR_PREVAILING_DEF_IRONLY_EXP: { + // We can only check for address uses after we merge the modules. The + // reason is that this GV might have a copy in another module + // and in that module the address might be significant, but that + // copy will be LDPR_PREEMPTED_IR. + if (GV->hasLinkOnceODRLinkage()) + Maybe.insert(Sym.name); + keepGlobalValue(*GV, KeptAliases); + break; + } } + + free(Sym.name); + free(Sym.comdat_key); + Sym.name = nullptr; + Sym.comdat_key = nullptr; } - CodeGen->setCodePICModel(output_type); - CodeGen->setDebugInfo(LTO_DEBUG_MODEL_DWARF); - if (!options::mcpu.empty()) - CodeGen->setCpu(options::mcpu.c_str()); + ValueToValueMapTy VM; + LocalValueMaterializer Materializer(Drop); + for (GlobalAlias *GA : KeptAliases) { + // Gold told us to keep GA. It is possible that a GV usied in the aliasee + // expression is being dropped. If that is the case, that GV must be copied. + Constant *Aliasee = GA->getAliasee(); + Constant *Replacement = mapConstantToLocalCopy(Aliasee, VM, &Materializer); + if (Aliasee != Replacement) + GA->setAliasee(Replacement); + } - if (options::generate_bc_file != options::BC_NO) { - std::string path; - if (options::generate_bc_file == options::BC_ONLY) - path = output_name; - else if (!options::bc_path.empty()) - path = options::bc_path; - else - path = output_name + ".bc"; - std::string Error; - if (!CodeGen->writeMergedModules(path.c_str(), Error)) - (*message)(LDPL_FATAL, "Failed to write the output file."); - if (options::generate_bc_file == options::BC_ONLY) { - delete CodeGen; - exit(0); - } + for (auto *GV : Drop) + drop(*GV); + + return M; +} + +static void runLTOPasses(Module &M, TargetMachine &TM) { + PassManager passes; + PassManagerBuilder PMB; + PMB.LibraryInfo = new TargetLibraryInfo(Triple(TM.getTargetTriple())); + PMB.Inliner = createFunctionInliningPass(); + PMB.VerifyInput = true; + PMB.VerifyOutput = true; + PMB.LoopVectorize = true; + PMB.SLPVectorize = true; + PMB.populateLTOPassManager(passes, &TM); + passes.run(M); +} + +static void saveBCFile(StringRef Path, Module &M) { + std::error_code EC; + raw_fd_ostream OS(Path, EC, sys::fs::OpenFlags::F_None); + if (EC) + message(LDPL_FATAL, "Failed to write the output file."); + WriteBitcodeToFile(&M, OS); +} + +static void codegen(Module &M) { + const std::string &TripleStr = M.getTargetTriple(); + Triple TheTriple(TripleStr); + + std::string ErrMsg; + const Target *TheTarget = TargetRegistry::lookupTarget(TripleStr, ErrMsg); + if (!TheTarget) + message(LDPL_FATAL, "Target not found: %s", ErrMsg.c_str()); + + if (unsigned NumOpts = options::extra.size()) + cl::ParseCommandLineOptions(NumOpts, &options::extra[0]); + + SubtargetFeatures Features; + Features.getDefaultSubtargetFeatures(TheTriple); + for (const std::string &A : MAttrs) + Features.AddFeature(A); + + TargetOptions Options = InitTargetOptionsFromCodeGenFlags(); + std::unique_ptr<TargetMachine> TM(TheTarget->createTargetMachine( + TripleStr, options::mcpu, Features.getString(), Options, RelocationModel, + CodeModel::Default, CodeGenOpt::Aggressive)); + + runLTOPasses(M, *TM); + + if (options::generate_bc_file == options::BC_SAVE_TEMPS) + saveBCFile(output_name + ".opt.bc", M); + + PassManager CodeGenPasses; + CodeGenPasses.add(new DataLayoutPass()); + + SmallString<128> Filename; + int FD; + if (options::obj_path.empty()) { + std::error_code EC = + sys::fs::createTemporaryFile("lto-llvm", "o", FD, Filename); + if (EC) + message(LDPL_FATAL, "Could not create temporary file: %s", + EC.message().c_str()); + } else { + Filename = options::obj_path; + std::error_code EC = + sys::fs::openFileForWrite(Filename.c_str(), FD, sys::fs::F_None); + if (EC) + message(LDPL_FATAL, "Could not open file: %s", EC.message().c_str()); } - std::string ObjPath; { - const char *Temp; - std::string Error; - if (!CodeGen->compile_to_file(&Temp, /*DisableOpt*/ false, /*DisableInline*/ - false, /*DisableGVNLoadPRE*/ false, Error)) - (*message)(LDPL_ERROR, "Could not produce a combined object file\n"); - ObjPath = Temp; + raw_fd_ostream OS(FD, true); + formatted_raw_ostream FOS(OS); + + if (TM->addPassesToEmitFile(CodeGenPasses, FOS, + TargetMachine::CGFT_ObjectFile)) + message(LDPL_FATAL, "Failed to setup codegen"); + CodeGenPasses.run(M); } - delete CodeGen; - for (std::list<claimed_file>::iterator I = Modules.begin(), - E = Modules.end(); I != E; ++I) { - for (unsigned i = 0; i != I->syms.size(); ++i) { - ld_plugin_symbol &sym = I->syms[i]; - free(sym.name); + if (add_input_file(Filename.c_str()) != LDPS_OK) + message(LDPL_FATAL, + "Unable to add .o file to the link. File left behind in: %s", + Filename.c_str()); + + if (options::obj_path.empty()) + Cleanup.push_back(Filename.c_str()); +} + +/// gold informs us that all symbols have been read. At this point, we use +/// get_symbols to see if any of our definitions have been overridden by a +/// native object file. Then, perform optimization and codegen. +static ld_plugin_status allSymbolsReadHook(raw_fd_ostream *ApiFile) { + if (Modules.empty()) + return LDPS_OK; + + LLVMContext Context; + std::unique_ptr<Module> Combined(new Module("ld-temp.o", Context)); + Linker L(Combined.get()); + + std::string DefaultTriple = sys::getDefaultTargetTriple(); + + StringSet<> Internalize; + StringSet<> Maybe; + for (claimed_file &F : Modules) { + std::unique_ptr<Module> M = + getModuleForFile(Context, F, ApiFile, Internalize, Maybe); + if (!options::triple.empty()) + M->setTargetTriple(options::triple.c_str()); + else if (M->getTargetTriple().empty()) { + M->setTargetTriple(DefaultTriple); } + + if (L.linkInModule(M.get())) + message(LDPL_FATAL, "Failed to link module"); } - if ((*add_input_file)(ObjPath.c_str()) != LDPS_OK) { - (*message)(LDPL_ERROR, "Unable to add .o file to the link."); - (*message)(LDPL_ERROR, "File left behind in: %s", ObjPath.c_str()); - return LDPS_ERR; + for (const auto &Name : Internalize) { + GlobalValue *GV = Combined->getNamedValue(Name.first()); + if (GV) + internalize(*GV); } - if (!options::extra_library_path.empty() && - set_extra_library_path(options::extra_library_path.c_str()) != LDPS_OK) { - (*message)(LDPL_ERROR, "Unable to set the extra library path."); - return LDPS_ERR; + for (const auto &Name : Maybe) { + GlobalValue *GV = Combined->getNamedValue(Name.first()); + if (!GV) + continue; + GV->setLinkage(GlobalValue::LinkOnceODRLinkage); + if (canBeOmittedFromSymbolTable(GV)) + internalize(*GV); } - if (options::obj_path.empty()) - Cleanup.push_back(ObjPath); + if (options::generate_bc_file != options::BC_NO) { + std::string path; + if (options::generate_bc_file == options::BC_ONLY) + path = output_name; + else + path = output_name + ".bc"; + saveBCFile(path, *L.getModule()); + if (options::generate_bc_file == options::BC_ONLY) + return LDPS_OK; + } + + codegen(*L.getModule()); + + if (!options::extra_library_path.empty() && + set_extra_library_path(options::extra_library_path.c_str()) != LDPS_OK) + message(LDPL_FATAL, "Unable to set the extra library path."); return LDPS_OK; } +static ld_plugin_status all_symbols_read_hook(void) { + ld_plugin_status Ret; + if (!options::generate_api_file) { + Ret = allSymbolsReadHook(nullptr); + } else { + std::error_code EC; + raw_fd_ostream ApiFile("apifile.txt", EC, sys::fs::F_None); + if (EC) + message(LDPL_FATAL, "Unable to open apifile.txt for writing: %s", + EC.message().c_str()); + Ret = allSymbolsReadHook(&ApiFile); + } + + if (options::generate_bc_file == options::BC_ONLY) + exit(0); + + return Ret; +} + static ld_plugin_status cleanup_hook(void) { - for (int i = 0, e = Cleanup.size(); i != e; ++i) { - std::error_code EC = sys::fs::remove(Cleanup[i]); + for (std::string &Name : Cleanup) { + std::error_code EC = sys::fs::remove(Name); if (EC) - (*message)(LDPL_ERROR, "Failed to delete '%s': %s", Cleanup[i].c_str(), - EC.message().c_str()); + message(LDPL_ERROR, "Failed to delete '%s': %s", Name.c_str(), + EC.message().c_str()); } return LDPS_OK; |