//===- Reader.cpp - Code to read bytecode files ---------------------------===// // // This library implements the functionality defined in llvm/Bytecode/Reader.h // // Note that this library should be as fast as possible, reentrant, and // threadsafe!! // // TODO: Return error messages to caller instead of printing them out directly. // TODO: Allow passing in an option to ignore the symbol table // //===----------------------------------------------------------------------===// #include "ReaderInternals.h" #include "llvm/Bytecode/Reader.h" #include "llvm/Bytecode/Format.h" #include "llvm/Constants.h" #include "llvm/iPHINode.h" #include "llvm/iOther.h" #include "llvm/Module.h" #include "Support/StringExtras.h" #include "Config/unistd.h" #include "Config/sys/mman.h" #include "Config/sys/stat.h" #include "Config/sys/types.h" #include #include static inline void ALIGN32(const unsigned char *&begin, const unsigned char *end) { if (align32(begin, end)) throw std::string("Alignment error in buffer: read past end of block."); } void BytecodeParser::getTypeSlot(const Type *Ty, unsigned &Slot) { if (Ty->isPrimitiveType()) { Slot = Ty->getPrimitiveID(); } else { // Check the function level types first... TypeValuesListTy::iterator I = find(FunctionTypeValues.begin(), FunctionTypeValues.end(), Ty); if (I != FunctionTypeValues.end()) { Slot = FirstDerivedTyID + ModuleTypeValues.size() + (&*I - &FunctionTypeValues[0]); } else { I = find(ModuleTypeValues.begin(), ModuleTypeValues.end(), Ty); if (I == ModuleTypeValues.end()) throw std::string("Didn't find type in ModuleTypeValues."); Slot = FirstDerivedTyID + (&*I - &ModuleTypeValues[0]); } } //cerr << "getTypeSlot '" << Ty->getName() << "' = " << Slot << "\n"; } const Type *BytecodeParser::getType(unsigned ID) { if (ID < Type::NumPrimitiveIDs) { const Type *T = Type::getPrimitiveType((Type::PrimitiveID)ID); if (T) return T; } //cerr << "Looking up Type ID: " << ID << "\n"; const Value *V = getValue(Type::TypeTy, ID, false); return cast_or_null(V); } int BytecodeParser::insertValue(Value *Val, ValueTable &ValueTab) { assert((!HasImplicitZeroInitializer || !isa(Val) || Val->getType()->isPrimitiveType() || !cast(Val)->isNullValue()) && "Cannot read null values from bytecode!"); unsigned type; getTypeSlot(Val->getType(), type); assert(type != Type::TypeTyID && "Types should never be insertValue'd!"); if (ValueTab.size() <= type) { unsigned OldSize = ValueTab.size(); ValueTab.resize(type+1); while (OldSize != type+1) ValueTab[OldSize++] = new ValueList(); } //cerr << "insertValue Values[" << type << "][" << ValueTab[type].size() // << "] = " << Val << "\n"; ValueTab[type]->push_back(Val); bool HasOffset = HasImplicitZeroInitializer && !Val->getType()->isPrimitiveType(); return ValueTab[type]->size()-1 + HasOffset; } void BytecodeParser::setValueTo(ValueTable &ValueTab, unsigned Slot, Value *Val) { assert(&ValueTab == &ModuleValues && "Can only setValueTo on Module values!"); unsigned type; getTypeSlot(Val->getType(), type); assert((!HasImplicitZeroInitializer || Slot != 0) && "Cannot change zero init"); assert(type < ValueTab.size() && Slot <= ValueTab[type]->size()); ValueTab[type]->setOperand(Slot-HasImplicitZeroInitializer, Val); } Value *BytecodeParser::getValue(const Type *Ty, unsigned oNum, bool Create) { unsigned Num = oNum; unsigned type; // The type plane it lives in... getTypeSlot(Ty, type); if (type == Type::TypeTyID) { // The 'type' plane has implicit values assert(Create == false); if (Num < Type::NumPrimitiveIDs) { const Type *T = Type::getPrimitiveType((Type::PrimitiveID)Num); if (T) return (Value*)T; // Asked for a primitive type... } // Otherwise, derived types need offset... Num -= FirstDerivedTyID; // Is it a module-level type? if (Num < ModuleTypeValues.size()) return (Value*)ModuleTypeValues[Num].get(); // Nope, is it a function-level type? Num -= ModuleTypeValues.size(); if (Num < FunctionTypeValues.size()) return (Value*)FunctionTypeValues[Num].get(); return 0; } if (HasImplicitZeroInitializer && type >= FirstDerivedTyID) { if (Num == 0) return Constant::getNullValue(Ty); --Num; } if (type < ModuleValues.size()) { if (Num < ModuleValues[type]->size()) return ModuleValues[type]->getOperand(Num); Num -= ModuleValues[type]->size(); } if (Values.size() > type && Values[type]->size() > Num) return Values[type]->getOperand(Num); if (!Create) return 0; // Do not create a placeholder? Value *d = 0; switch (Ty->getPrimitiveID()) { case Type::LabelTyID: d = new BBPHolder(Ty, oNum); break; default: d = new ValPHolder(Ty, oNum); break; } assert(d != 0 && "How did we not make something?"); if (insertValue(d, LateResolveValues) == -1) return 0; return d; } /// getConstantValue - Just like getValue, except that it returns a null pointer /// only on error. It always returns a constant (meaning that if the value is /// defined, but is not a constant, that is an error). If the specified /// constant hasn't been parsed yet, a placeholder is defined and used. Later, /// after the real value is parsed, the placeholder is eliminated. /// Constant *BytecodeParser::getConstantValue(const Type *Ty, unsigned Slot) { if (Value *V = getValue(Ty, Slot, false)) return dyn_cast(V); // If we already have the value parsed... std::pair Key(Ty, Slot); GlobalRefsType::iterator I = GlobalRefs.lower_bound(Key); if (I != GlobalRefs.end() && I->first == Key) { BCR_TRACE(5, "Previous forward ref found!\n"); return cast(I->second); } else { // Create a placeholder for the constant reference and // keep track of the fact that we have a forward ref to recycle it BCR_TRACE(5, "Creating new forward ref to a constant!\n"); Constant *C = new ConstPHolder(Ty, Slot); // Keep track of the fact that we have a forward ref to recycle it GlobalRefs.insert(I, std::make_pair(Key, C)); return C; } } void BytecodeParser::postResolveValues(ValueTable &ValTab) { while (!ValTab.empty()) { ValueList &DL = *ValTab.back(); ValTab.pop_back(); while (!DL.empty()) { Value *D = DL.back(); unsigned IDNumber = getValueIDNumberFromPlaceHolder(D); DL.pop_back(); Value *NewDef = getValue(D->getType(), IDNumber, false); if (NewDef == 0) { throw std::string("Unresolvable reference found: <" + D->getType()->getDescription() + ">:" + utostr(IDNumber) + "."); } else { // Fixup all of the uses of this placeholder def... D->replaceAllUsesWith(NewDef); // Now that all the uses are gone, delete the placeholder... // If we couldn't find a def (error case), then leak a little delete D; // memory, 'cause otherwise we can't remove all uses! } } delete &DL; } } std::auto_ptr BytecodeParser::ParseBasicBlock(const unsigned char *&Buf, const unsigned char *EndBuf) { std::auto_ptr BB(new BasicBlock()); while (Buf < EndBuf) { Instruction *Inst; ParseInstruction(Buf, EndBuf, Inst); if (Inst == 0) { throw std::string("Could not parse Instruction."); } if (insertValue(Inst, Values) == -1) { throw std::string("Could not insert value."); } BB->getInstList().push_back(Inst); BCR_TRACE(4, Inst); } return BB; } void BytecodeParser::ParseSymbolTable(const unsigned char *&Buf, const unsigned char *EndBuf, SymbolTable *ST) { while (Buf < EndBuf) { // Symtab block header: [num entries][type id number] unsigned NumEntries, Typ; if (read_vbr(Buf, EndBuf, NumEntries) || read_vbr(Buf, EndBuf, Typ)) throw Error_readvbr; const Type *Ty = getType(Typ); if (Ty == 0) throw std::string("Invalid type read in symbol table."); BCR_TRACE(3, "Plane Type: '" << Ty << "' with " << NumEntries << " entries\n"); for (unsigned i = 0; i < NumEntries; ++i) { // Symtab entry: [def slot #][name] unsigned slot; if (read_vbr(Buf, EndBuf, slot)) throw Error_readvbr; std::string Name; if (read(Buf, EndBuf, Name, false)) // Not aligned... throw std::string("Buffer not aligned."); Value *V = getValue(Ty, slot, false); // Find mapping... if (V == 0) { BCR_TRACE(3, "FAILED LOOKUP: Slot #" << slot << "\n"); throw std::string("Failed value look-up."); } BCR_TRACE(4, "Map: '" << Name << "' to #" << slot << ":" << *V; if (!isa(V)) std::cerr << "\n"); V->setName(Name, ST); } } if (Buf > EndBuf) throw std::string("Tried to read past end of buffer."); } void BytecodeParser::ResolveReferencesToValue(Value *NewV, unsigned Slot) { GlobalRefsType::iterator I = GlobalRefs.find(std::make_pair(NewV->getType(), Slot)); if (I == GlobalRefs.end()) return; // Never forward referenced? BCR_TRACE(3, "Mutating forward refs!\n"); Value *VPH = I->second; // Get the placeholder... VPH->replaceAllUsesWith(NewV); // If this is a global variable being resolved, remove the placeholder from // the module... if (GlobalValue* GVal = dyn_cast(NewV)) GVal->getParent()->getGlobalList().remove(cast(VPH)); delete VPH; // Delete the old placeholder GlobalRefs.erase(I); // Remove the map entry for it } void BytecodeParser::ParseFunction(const unsigned char *&Buf, const unsigned char *EndBuf) { if (FunctionSignatureList.empty()) throw std::string("FunctionSignatureList empty!"); Function *F = FunctionSignatureList.back().first; unsigned FunctionSlot = FunctionSignatureList.back().second; FunctionSignatureList.pop_back(); // Save the information for future reading of the function LazyFunctionInfo *LFI = new LazyFunctionInfo(); LFI->Buf = Buf; LFI->EndBuf = EndBuf; LFI->FunctionSlot = FunctionSlot; LazyFunctionLoadMap[F] = LFI; // Pretend we've `parsed' this function Buf = EndBuf; } void BytecodeParser::materializeFunction(Function* F) { // Find {start, end} pointers and slot in the map. If not there, we're done. std::map::iterator Fi = LazyFunctionLoadMap.find(F); if (Fi == LazyFunctionLoadMap.end()) return; LazyFunctionInfo *LFI = Fi->second; const unsigned char *Buf = LFI->Buf; const unsigned char *EndBuf = LFI->EndBuf; unsigned FunctionSlot = LFI->FunctionSlot; LazyFunctionLoadMap.erase(Fi); delete LFI; GlobalValue::LinkageTypes Linkage = GlobalValue::ExternalLinkage; if (!hasInternalMarkerOnly) { unsigned LinkageType; if (read_vbr(Buf, EndBuf, LinkageType)) throw std::string("ParseFunction: Error reading from buffer."); if (LinkageType & ~0x3) throw std::string("Invalid linkage type for Function."); Linkage = (GlobalValue::LinkageTypes)LinkageType; } else { // We used to only support two linkage models: internal and external unsigned isInternal; if (read_vbr(Buf, EndBuf, isInternal)) throw std::string("ParseFunction: Error reading from buffer."); if (isInternal) Linkage = GlobalValue::InternalLinkage; } F->setLinkage(Linkage); const FunctionType::ParamTypes &Params =F->getFunctionType()->getParamTypes(); Function::aiterator AI = F->abegin(); for (FunctionType::ParamTypes::const_iterator It = Params.begin(); It != Params.end(); ++It, ++AI) { if (insertValue(AI, Values) == -1) throw std::string("Error reading function arguments!"); } while (Buf < EndBuf) { unsigned Type, Size; const unsigned char *OldBuf = Buf; readBlock(Buf, EndBuf, Type, Size); switch (Type) { case BytecodeFormat::ConstantPool: { BCR_TRACE(2, "BLOCK BytecodeFormat::ConstantPool: {\n"); ParseConstantPool(Buf, Buf+Size, Values, FunctionTypeValues); break; } case BytecodeFormat::BasicBlock: { BCR_TRACE(2, "BLOCK BytecodeFormat::BasicBlock: {\n"); std::auto_ptr BB = ParseBasicBlock(Buf, Buf+Size); if (!BB.get() || insertValue(BB.get(), Values) == -1) throw std::string("Parse error: BasicBlock"); F->getBasicBlockList().push_back(BB.release()); break; } case BytecodeFormat::SymbolTable: { BCR_TRACE(2, "BLOCK BytecodeFormat::SymbolTable: {\n"); ParseSymbolTable(Buf, Buf+Size, &F->getSymbolTable()); break; } default: BCR_TRACE(2, "BLOCK :ignored! {\n"); Buf += Size; if (OldBuf > Buf) throw std::string("Wrapped around reading bytecode."); break; } BCR_TRACE(2, "} end block\n"); // Malformed bc file if read past end of block. ALIGN32(Buf, EndBuf); } // Check for unresolvable references postResolveValues(LateResolveValues); //ResolveReferencesToValue(F, FunctionSlot); // Clear out function-level types... FunctionTypeValues.clear(); freeTable(Values); } void BytecodeParser::ParseModuleGlobalInfo(const unsigned char *&Buf, const unsigned char *End) { if (!FunctionSignatureList.empty()) throw std::string("Two ModuleGlobalInfo packets found!"); // Read global variables... unsigned VarType; if (read_vbr(Buf, End, VarType)) throw Error_readvbr; while (VarType != Type::VoidTyID) { // List is terminated by Void unsigned SlotNo; GlobalValue::LinkageTypes Linkage; if (!hasInternalMarkerOnly) { // VarType Fields: bit0 = isConstant, bit1 = hasInitializer, // bit2,3 = Linkage, bit4+ = slot# SlotNo = VarType >> 4; Linkage = (GlobalValue::LinkageTypes)((VarType >> 2) & 3); } else { // VarType Fields: bit0 = isConstant, bit1 = hasInitializer, // bit2 = isInternal, bit3+ = slot# SlotNo = VarType >> 3; Linkage = (VarType & 4) ? GlobalValue::InternalLinkage : GlobalValue::ExternalLinkage; } const Type *Ty = getType(SlotNo); if (!Ty || !isa(Ty)) throw std::string("Global not pointer type! Ty = " + Ty->getDescription()); const Type *ElTy = cast(Ty)->getElementType(); // Create the global variable... GlobalVariable *GV = new GlobalVariable(ElTy, VarType & 1, Linkage, 0, "", TheModule); int DestSlot = insertValue(GV, ModuleValues); if (DestSlot == -1) throw Error_DestSlot; BCR_TRACE(2, "Global Variable of type: " << *Ty << "\n"); ResolveReferencesToValue(GV, (unsigned)DestSlot); if (VarType & 2) { // Does it have an initializer? unsigned InitSlot; if (read_vbr(Buf, End, InitSlot)) throw Error_readvbr; GlobalInits.push_back(std::make_pair(GV, InitSlot)); } if (read_vbr(Buf, End, VarType)) throw Error_readvbr; } // Read the function objects for all of the functions that are coming unsigned FnSignature; if (read_vbr(Buf, End, FnSignature)) throw Error_readvbr; while (FnSignature != Type::VoidTyID) { // List is terminated by Void const Type *Ty = getType(FnSignature); if (!Ty || !isa(Ty) || !isa(cast(Ty)->getElementType())) { throw std::string("Function not ptr to func type! Ty = " + Ty->getDescription()); } // We create functions by passing the underlying FunctionType to create... Ty = cast(Ty)->getElementType(); // When the ModuleGlobalInfo section is read, we load the type of each // function and the 'ModuleValues' slot that it lands in. We then load a // placeholder into its slot to reserve it. When the function is loaded, // this placeholder is replaced. // Insert the placeholder... Function *Func = new Function(cast(Ty), GlobalValue::InternalLinkage, "", TheModule); int DestSlot = insertValue(Func, ModuleValues); if (DestSlot == -1) throw Error_DestSlot; ResolveReferencesToValue(Func, (unsigned)DestSlot); // Keep track of this information in a list that is emptied as functions are // loaded... // FunctionSignatureList.push_back(std::make_pair(Func, DestSlot)); if (read_vbr(Buf, End, FnSignature)) throw Error_readvbr; BCR_TRACE(2, "Function of type: " << Ty << "\n"); } ALIGN32(Buf, End); // Now that the function signature list is set up, reverse it so that we can // remove elements efficiently from the back of the vector. std::reverse(FunctionSignatureList.begin(), FunctionSignatureList.end()); // This is for future proofing... in the future extra fields may be added that // we don't understand, so we transparently ignore them. // Buf = End; } void BytecodeParser::ParseVersionInfo(const unsigned char *&Buf, const unsigned char *EndBuf) { unsigned Version; if (read_vbr(Buf, EndBuf, Version)) throw Error_readvbr; // Unpack version number: low four bits are for flags, top bits = version Module::Endianness Endianness; Module::PointerSize PointerSize; Endianness = (Version & 1) ? Module::BigEndian : Module::LittleEndian; PointerSize = (Version & 2) ? Module::Pointer64 : Module::Pointer32; bool hasNoEndianness = Version & 4; bool hasNoPointerSize = Version & 8; RevisionNum = Version >> 4; // Default values for the current bytecode version HasImplicitZeroInitializer = true; hasInternalMarkerOnly = false; FirstDerivedTyID = 14; switch (RevisionNum) { case 0: // Initial revision // Version #0 didn't have any of the flags stored correctly, and in fact as // only valid with a 14 in the flags values. Also, it does not support // encoding zero initializers for arrays compactly. // if (Version != 14) throw std::string("Unknown revision 0 flags?"); HasImplicitZeroInitializer = false; Endianness = Module::BigEndian; PointerSize = Module::Pointer64; hasInternalMarkerOnly = true; hasNoEndianness = hasNoPointerSize = false; break; case 1: // Version #1 has four bit fields: isBigEndian, hasLongPointers, // hasNoEndianness, and hasNoPointerSize. hasInternalMarkerOnly = true; break; case 2: // Version #2 added information about all 4 linkage types instead of just // having internal and external. break; default: throw std::string("Unknown bytecode version number!"); } if (hasNoEndianness) Endianness = Module::AnyEndianness; if (hasNoPointerSize) PointerSize = Module::AnyPointerSize; TheModule->setEndianness(Endianness); TheModule->setPointerSize(PointerSize); BCR_TRACE(1, "Bytecode Rev = " << (unsigned)RevisionNum << "\n"); BCR_TRACE(1, "Endianness/PointerSize = " << Endianness << "," << PointerSize << "\n"); BCR_TRACE(1, "HasImplicitZeroInit = " << HasImplicitZeroInitializer << "\n"); } void BytecodeParser::ParseModule(const unsigned char *Buf, const unsigned char *EndBuf) { unsigned Type, Size; readBlock(Buf, EndBuf, Type, Size); if (Type != BytecodeFormat::Module || Buf+Size != EndBuf) throw std::string("Expected Module packet! B: "+ utostr((unsigned)(intptr_t)Buf) + ", S: "+utostr(Size)+ " E: "+utostr((unsigned)(intptr_t)EndBuf)); // Hrm, not a class? BCR_TRACE(0, "BLOCK BytecodeFormat::Module: {\n"); FunctionSignatureList.clear(); // Just in case... // Read into instance variables... ParseVersionInfo(Buf, EndBuf); ALIGN32(Buf, EndBuf); while (Buf < EndBuf) { const unsigned char *OldBuf = Buf; readBlock(Buf, EndBuf, Type, Size); switch (Type) { case BytecodeFormat::GlobalTypePlane: BCR_TRACE(1, "BLOCK BytecodeFormat::GlobalTypePlane: {\n"); ParseGlobalTypes(Buf, Buf+Size); break; case BytecodeFormat::ModuleGlobalInfo: BCR_TRACE(1, "BLOCK BytecodeFormat::ModuleGlobalInfo: {\n"); ParseModuleGlobalInfo(Buf, Buf+Size); break; case BytecodeFormat::ConstantPool: BCR_TRACE(1, "BLOCK BytecodeFormat::ConstantPool: {\n"); ParseConstantPool(Buf, Buf+Size, ModuleValues, ModuleTypeValues); break; case BytecodeFormat::Function: { BCR_TRACE(1, "BLOCK BytecodeFormat::Function: {\n"); ParseFunction(Buf, Buf+Size); break; } case BytecodeFormat::SymbolTable: BCR_TRACE(1, "BLOCK BytecodeFormat::SymbolTable: {\n"); ParseSymbolTable(Buf, Buf+Size, &TheModule->getSymbolTable()); break; default: Buf += Size; if (OldBuf > Buf) throw std::string("Expected Module Block!"); break; } BCR_TRACE(1, "} end block\n"); ALIGN32(Buf, EndBuf); } // After the module constant pool has been read, we can safely initialize // global variables... while (!GlobalInits.empty()) { GlobalVariable *GV = GlobalInits.back().first; unsigned Slot = GlobalInits.back().second; GlobalInits.pop_back(); // Look up the initializer value... if (Value *V = getValue(GV->getType()->getElementType(), Slot, false)) { if (GV->hasInitializer()) throw std::string("Global *already* has an initializer?!"); GV->setInitializer(cast(V)); } else throw std::string("Cannot find initializer value."); } if (!FunctionSignatureList.empty()) throw std::string("Function expected, but bytecode stream ended!"); BCR_TRACE(0, "} end block\n\n"); } void BytecodeParser::ParseBytecode(const unsigned char *Buf, unsigned Length, const std::string &ModuleID) { unsigned char *EndBuf = (unsigned char*)(Buf + Length); // Read and check signature... unsigned Sig; if (read(Buf, EndBuf, Sig) || Sig != ('l' | ('l' << 8) | ('v' << 16) | ('m' << 24))) throw std::string("Invalid bytecode signature!"); TheModule = new Module(ModuleID); try { ParseModule(Buf, EndBuf); } catch (std::string &Error) { freeState(); // Must destroy handles before deleting module! delete TheModule; TheModule = 0; throw Error; } }