| //===-LTOModule.cpp - LLVM Link Time Optimizer ----------------------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file implements the Link Time Optimization library. This library is |
| // intended to be used by linker to optimize code at link time. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "LTOModule.h" |
| |
| #include "llvm/Module.h" |
| #include "llvm/ModuleProvider.h" |
| #include "llvm/ADT/OwningPtr.h" |
| #include "llvm/Bitcode/ReaderWriter.h" |
| #include "llvm/Support/SystemUtils.h" |
| #include "llvm/Support/Mangler.h" |
| #include "llvm/Support/MemoryBuffer.h" |
| #include "llvm/Support/MathExtras.h" |
| #include "llvm/System/Path.h" |
| #include "llvm/System/Process.h" |
| #include "llvm/Target/SubtargetFeature.h" |
| #include "llvm/Target/TargetMachine.h" |
| #include "llvm/Target/TargetMachineRegistry.h" |
| #include "llvm/Target/TargetAsmInfo.h" |
| |
| #include <fstream> |
| |
| using namespace llvm; |
| |
| bool LTOModule::isBitcodeFile(const void* mem, size_t length) |
| { |
| return ( llvm::sys::IdentifyFileType((char*)mem, length) |
| == llvm::sys::Bitcode_FileType ); |
| } |
| |
| bool LTOModule::isBitcodeFile(const char* path) |
| { |
| return llvm::sys::Path(path).isBitcodeFile(); |
| } |
| |
| bool LTOModule::isBitcodeFileForTarget(const void* mem, size_t length, |
| const char* triplePrefix) |
| { |
| MemoryBuffer* buffer = makeBuffer(mem, length); |
| if ( buffer == NULL ) |
| return false; |
| return isTargetMatch(buffer, triplePrefix); |
| } |
| |
| |
| bool LTOModule::isBitcodeFileForTarget(const char* path, |
| const char* triplePrefix) |
| { |
| MemoryBuffer *buffer = MemoryBuffer::getFile(path); |
| if (buffer == NULL) |
| return false; |
| return isTargetMatch(buffer, triplePrefix); |
| } |
| |
| // takes ownership of buffer |
| bool LTOModule::isTargetMatch(MemoryBuffer* buffer, const char* triplePrefix) |
| { |
| OwningPtr<ModuleProvider> mp(getBitcodeModuleProvider(buffer)); |
| // on success, mp owns buffer and both are deleted at end of this method |
| if ( !mp ) { |
| delete buffer; |
| return false; |
| } |
| std::string actualTarget = mp->getModule()->getTargetTriple(); |
| return ( strncmp(actualTarget.c_str(), triplePrefix, |
| strlen(triplePrefix)) == 0); |
| } |
| |
| |
| LTOModule::LTOModule(Module* m, TargetMachine* t) |
| : _module(m), _target(t), _symbolsParsed(false) |
| { |
| } |
| |
| LTOModule* LTOModule::makeLTOModule(const char* path, std::string& errMsg) |
| { |
| OwningPtr<MemoryBuffer> buffer(MemoryBuffer::getFile(path, &errMsg)); |
| if ( !buffer ) |
| return NULL; |
| return makeLTOModule(buffer.get(), errMsg); |
| } |
| |
| /// makeBuffer - create a MemoryBuffer from a memory range. |
| /// MemoryBuffer requires the byte past end of the buffer to be a zero. |
| /// We might get lucky and already be that way, otherwise make a copy. |
| /// Also if next byte is on a different page, don't assume it is readable. |
| MemoryBuffer* LTOModule::makeBuffer(const void* mem, size_t length) |
| { |
| const char* startPtr = (char*)mem; |
| const char* endPtr = startPtr+length; |
| if ( (((uintptr_t)endPtr & (sys::Process::GetPageSize()-1)) == 0) |
| || (*endPtr != 0) ) |
| return MemoryBuffer::getMemBufferCopy(startPtr, endPtr); |
| else |
| return MemoryBuffer::getMemBuffer(startPtr, endPtr); |
| } |
| |
| |
| LTOModule* LTOModule::makeLTOModule(const void* mem, size_t length, |
| std::string& errMsg) |
| { |
| OwningPtr<MemoryBuffer> buffer(makeBuffer(mem, length)); |
| if ( !buffer ) |
| return NULL; |
| return makeLTOModule(buffer.get(), errMsg); |
| } |
| |
| /// getFeatureString - Return a string listing the features associated with the |
| /// target triple. |
| /// |
| /// FIXME: This is an inelegant way of specifying the features of a |
| /// subtarget. It would be better if we could encode this information into the |
| /// IR. See <rdar://5972456>. |
| std::string getFeatureString(const char *TargetTriple) { |
| SubtargetFeatures Features; |
| |
| if (strncmp(TargetTriple, "powerpc-apple-", 14) == 0) { |
| Features.AddFeature("altivec", true); |
| } else if (strncmp(TargetTriple, "powerpc64-apple-", 16) == 0) { |
| Features.AddFeature("64bit", true); |
| Features.AddFeature("altivec", true); |
| } |
| |
| return Features.getString(); |
| } |
| |
| LTOModule* LTOModule::makeLTOModule(MemoryBuffer* buffer, std::string& errMsg) |
| { |
| // parse bitcode buffer |
| OwningPtr<Module> m(ParseBitcodeFile(buffer, &errMsg)); |
| if ( !m ) |
| return NULL; |
| // find machine architecture for this module |
| const TargetMachineRegistry::entry* march = |
| TargetMachineRegistry::getClosestStaticTargetForModule(*m, errMsg); |
| |
| if ( march == NULL ) |
| return NULL; |
| |
| // construct LTModule, hand over ownership of module and target |
| std::string FeatureStr = getFeatureString(m->getTargetTriple().c_str()); |
| TargetMachine* target = march->CtorFn(*m, FeatureStr); |
| return new LTOModule(m.take(), target); |
| } |
| |
| |
| const char* LTOModule::getTargetTriple() |
| { |
| return _module->getTargetTriple().c_str(); |
| } |
| |
| void LTOModule::addDefinedFunctionSymbol(Function* f, Mangler &mangler) |
| { |
| // add to list of defined symbols |
| addDefinedSymbol(f, mangler, true); |
| |
| // add external symbols referenced by this function. |
| for (Function::iterator b = f->begin(); b != f->end(); ++b) { |
| for (BasicBlock::iterator i = b->begin(); i != b->end(); ++i) { |
| for (unsigned count = 0, total = i->getNumOperands(); |
| count != total; ++count) { |
| findExternalRefs(i->getOperand(count), mangler); |
| } |
| } |
| } |
| } |
| |
| void LTOModule::addDefinedDataSymbol(GlobalValue* v, Mangler &mangler) |
| { |
| // add to list of defined symbols |
| addDefinedSymbol(v, mangler, false); |
| |
| // add external symbols referenced by this data. |
| for (unsigned count = 0, total = v->getNumOperands(); |
| count != total; ++count) { |
| findExternalRefs(v->getOperand(count), mangler); |
| } |
| } |
| |
| |
| void LTOModule::addDefinedSymbol(GlobalValue* def, Mangler &mangler, |
| bool isFunction) |
| { |
| // string is owned by _defines |
| const char* symbolName = ::strdup(mangler.getValueName(def).c_str()); |
| |
| // set alignment part log2() can have rounding errors |
| uint32_t align = def->getAlignment(); |
| uint32_t attr = align ? CountTrailingZeros_32(def->getAlignment()) : 0; |
| |
| // set permissions part |
| if ( isFunction ) |
| attr |= LTO_SYMBOL_PERMISSIONS_CODE; |
| else { |
| GlobalVariable* gv = dyn_cast<GlobalVariable>(def); |
| if ( (gv != NULL) && gv->isConstant() ) |
| attr |= LTO_SYMBOL_PERMISSIONS_RODATA; |
| else |
| attr |= LTO_SYMBOL_PERMISSIONS_DATA; |
| } |
| |
| // set definition part |
| if ( def->hasWeakLinkage() || def->hasLinkOnceLinkage() ) { |
| attr |= LTO_SYMBOL_DEFINITION_WEAK; |
| } |
| else if ( def->hasCommonLinkage()) { |
| attr |= LTO_SYMBOL_DEFINITION_TENTATIVE; |
| } |
| else { |
| attr |= LTO_SYMBOL_DEFINITION_REGULAR; |
| } |
| |
| // set scope part |
| if ( def->hasHiddenVisibility() ) |
| attr |= LTO_SYMBOL_SCOPE_HIDDEN; |
| else if ( def->hasExternalLinkage() || def->hasWeakLinkage() |
| || def->hasLinkOnceLinkage() || def->hasCommonLinkage() ) |
| attr |= LTO_SYMBOL_SCOPE_DEFAULT; |
| else |
| attr |= LTO_SYMBOL_SCOPE_INTERNAL; |
| |
| // add to table of symbols |
| NameAndAttributes info; |
| info.name = symbolName; |
| info.attributes = (lto_symbol_attributes)attr; |
| _symbols.push_back(info); |
| _defines[info.name] = 1; |
| } |
| |
| void LTOModule::addAsmGlobalSymbol(const char *name) { |
| // string is owned by _defines |
| const char *symbolName = ::strdup(name); |
| uint32_t attr = LTO_SYMBOL_DEFINITION_REGULAR; |
| attr |= LTO_SYMBOL_SCOPE_DEFAULT; |
| |
| // add to table of symbols |
| NameAndAttributes info; |
| info.name = symbolName; |
| info.attributes = (lto_symbol_attributes)attr; |
| _symbols.push_back(info); |
| _defines[info.name] = 1; |
| } |
| |
| void LTOModule::addPotentialUndefinedSymbol(GlobalValue* decl, Mangler &mangler) |
| { |
| const char* name = mangler.getValueName(decl).c_str(); |
| // ignore all llvm.* symbols |
| if ( strncmp(name, "llvm.", 5) != 0 ) { |
| _undefines[name] = 1; |
| } |
| } |
| |
| |
| |
| // Find exeternal symbols referenced by VALUE. This is a recursive function. |
| void LTOModule::findExternalRefs(Value* value, Mangler &mangler) { |
| |
| if (GlobalValue* gv = dyn_cast<GlobalValue>(value)) { |
| if ( !gv->hasExternalLinkage() ) |
| addPotentialUndefinedSymbol(gv, mangler); |
| // If this is a variable definition, do not recursively process |
| // initializer. It might contain a reference to this variable |
| // and cause an infinite loop. The initializer will be |
| // processed in addDefinedDataSymbol(). |
| return; |
| } |
| |
| // GlobalValue, even with InternalLinkage type, may have operands with |
| // ExternalLinkage type. Do not ignore these operands. |
| if (Constant* c = dyn_cast<Constant>(value)) { |
| // Handle ConstantExpr, ConstantStruct, ConstantArry etc.. |
| for (unsigned i = 0, e = c->getNumOperands(); i != e; ++i) |
| findExternalRefs(c->getOperand(i), mangler); |
| } |
| } |
| |
| void LTOModule::lazyParseSymbols() |
| { |
| if ( !_symbolsParsed ) { |
| _symbolsParsed = true; |
| |
| // Use mangler to add GlobalPrefix to names to match linker names. |
| Mangler mangler(*_module, _target->getTargetAsmInfo()->getGlobalPrefix()); |
| |
| // add functions |
| for (Module::iterator f = _module->begin(); f != _module->end(); ++f) { |
| if ( f->isDeclaration() ) |
| addPotentialUndefinedSymbol(f, mangler); |
| else |
| addDefinedFunctionSymbol(f, mangler); |
| } |
| |
| // add data |
| for (Module::global_iterator v = _module->global_begin(), |
| e = _module->global_end(); v != e; ++v) { |
| if ( v->isDeclaration() ) |
| addPotentialUndefinedSymbol(v, mangler); |
| else |
| addDefinedDataSymbol(v, mangler); |
| } |
| |
| // add asm globals |
| const std::string &inlineAsm = _module->getModuleInlineAsm(); |
| const std::string glbl = ".globl"; |
| std::string asmSymbolName; |
| std::string::size_type pos = inlineAsm.find(glbl, 0); |
| while (pos != std::string::npos) { |
| // eat .globl |
| pos = pos + 6; |
| |
| // skip white space between .globl and symbol name |
| std::string::size_type pbegin = inlineAsm.find_first_not_of(' ', pos); |
| if (pbegin == std::string::npos) |
| break; |
| |
| // find end-of-line |
| std::string::size_type pend = inlineAsm.find_first_of('\n', pbegin); |
| if (pend == std::string::npos) |
| break; |
| |
| asmSymbolName.assign(inlineAsm, pbegin, pend - pbegin); |
| addAsmGlobalSymbol(asmSymbolName.c_str()); |
| |
| // search next .globl |
| pos = inlineAsm.find(glbl, pend); |
| } |
| |
| // make symbols for all undefines |
| for (StringSet::iterator it=_undefines.begin(); |
| it != _undefines.end(); ++it) { |
| // if this symbol also has a definition, then don't make an undefine |
| // because it is a tentative definition |
| if ( _defines.count(it->getKeyData(), it->getKeyData()+ |
| it->getKeyLength()) == 0 ) { |
| NameAndAttributes info; |
| info.name = it->getKeyData(); |
| info.attributes = LTO_SYMBOL_DEFINITION_UNDEFINED; |
| _symbols.push_back(info); |
| } |
| } |
| } |
| } |
| |
| |
| uint32_t LTOModule::getSymbolCount() |
| { |
| lazyParseSymbols(); |
| return _symbols.size(); |
| } |
| |
| |
| lto_symbol_attributes LTOModule::getSymbolAttributes(uint32_t index) |
| { |
| lazyParseSymbols(); |
| if ( index < _symbols.size() ) |
| return _symbols[index].attributes; |
| else |
| return lto_symbol_attributes(0); |
| } |
| |
| const char* LTOModule::getSymbolName(uint32_t index) |
| { |
| lazyParseSymbols(); |
| if ( index < _symbols.size() ) |
| return _symbols[index].name; |
| else |
| return NULL; |
| } |
| |