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c920c81739
llvm-mirror/lib/Bytecode/Reader/Reader.cpp
Chris Lattner c920c81739 Inline the postResolveValues method. It was poorly named anyway 
llvm-svn: 8976
2003-10-08 21:51:46 +00:00

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//===- 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 <algorithm>
#include <memory>
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.");
}
unsigned BytecodeParser::getTypeSlot(const Type *Ty) {
if (Ty->isPrimitiveType())
return Ty->getPrimitiveID();
// Check the function level types first...
TypeValuesListTy::iterator I = find(FunctionTypeValues.begin(),
FunctionTypeValues.end(), Ty);
if (I != FunctionTypeValues.end())
return FirstDerivedTyID + ModuleTypeValues.size() +
(&*I - &FunctionTypeValues[0]);
I = find(ModuleTypeValues.begin(), ModuleTypeValues.end(), Ty);
if (I == ModuleTypeValues.end())
throw std::string("Didn't find type in ModuleTypeValues.");
return FirstDerivedTyID + (&*I - &ModuleTypeValues[0]);
}
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";
if (ID < Type::NumPrimitiveIDs) {
const Type *T = Type::getPrimitiveType((Type::PrimitiveID)ID);
if (T) return T; // Asked for a primitive type...
}
// Otherwise, derived types need offset...
ID -= FirstDerivedTyID;
// Is it a module-level type?
if (ID < ModuleTypeValues.size())
return ModuleTypeValues[ID].get();
// Nope, is it a function-level type?
ID -= ModuleTypeValues.size();
if (ID < FunctionTypeValues.size())
return FunctionTypeValues[ID].get();
return 0;
}
int BytecodeParser::insertValue(Value *Val, ValueTable &ValueTab) {
assert((!HasImplicitZeroInitializer || !isa<Constant>(Val) ||
Val->getType()->isPrimitiveType() ||
!cast<Constant>(Val)->isNullValue()) &&
"Cannot read null values from bytecode!");
unsigned type = getTypeSlot(Val->getType());
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!");
assert((!HasImplicitZeroInitializer || Slot != 0) &&
"Cannot change zero init");
unsigned type = getTypeSlot(Val->getType());
assert(type < ValueTab.size() && Slot <= ValueTab[type]->size());
ValueTab[type]->setOperand(Slot-HasImplicitZeroInitializer, Val);
}
Value *BytecodeParser::getValue(const Type *Ty, unsigned oNum, bool Create) {
return getValue(getTypeSlot(Ty), oNum, Create);
}
Value *BytecodeParser::getValue(unsigned type, unsigned oNum, bool Create) {
assert(type != Type::TypeTyID && "getValue() cannot get types!");
unsigned Num = oNum;
if (HasImplicitZeroInitializer && type >= FirstDerivedTyID) {
if (Num == 0)
return Constant::getNullValue(getType(type));
--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?
const Type *Ty = getType(type);
Value *Val = type == Type::LabelTyID ? (Value*)new BBPHolder(Ty, oNum) :
(Value*)new ValPHolder(Ty, oNum);
assert(Val != 0 && "How did we not make something?");
if (insertValue(Val, LateResolveValues) == -1) return 0;
return Val;
}
/// 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<Constant>(V); // If we already have the value parsed...
std::pair<const Type*, unsigned> 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<Constant>(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;
}
}
std::auto_ptr<BasicBlock>
BytecodeParser::ParseBasicBlock(const unsigned char *&Buf,
const unsigned char *EndBuf) {
std::auto_ptr<BasicBlock> 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;
if (Typ == Type::TypeTyID)
V = (Value*)getType(slot);
else
V = getValue(Typ, slot, false); // Find mapping...
if (V == 0) throw std::string("Failed value look-up.");
BCR_TRACE(4, "Map: '" << Name << "' to #" << slot << ":" << *V;
if (!isa<Instruction>(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<GlobalValue>(NewV))
GVal->getParent()->getGlobalList().remove(cast<GlobalVariable>(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<Function*, LazyFunctionInfo*>::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<BasicBlock> 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 <unknown>: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
while (!LateResolveValues.empty()) {
ValueList &VL = *LateResolveValues.back();
LateResolveValues.pop_back();
while (!VL.empty()) {
Value *V = VL.back();
unsigned IDNumber = getValueIDNumberFromPlaceHolder(V);
VL.pop_back();
Value *NewVal = getValue(V->getType(), IDNumber, false);
if (NewVal == 0)
throw std::string("Unresolvable reference found: <" +
V->getType()->getDescription() + ">:" +
utostr(IDNumber) + ".");
// Fixup all of the uses of this placeholder def...
V->replaceAllUsesWith(NewVal);
// Now that all the uses are gone, delete the placeholder...
// If we couldn't find a def (error case), then leak a little
// memory, because otherwise we can't remove all uses!
delete V;
}
delete &VL;
}
// 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<PointerType>(Ty))
throw std::string("Global not pointer type! Ty = " +
Ty->getDescription());
const Type *ElTy = cast<PointerType>(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<PointerType>(Ty) ||
!isa<FunctionType>(cast<PointerType>(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<PointerType>(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<FunctionType>(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<Constant>(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;
}
}
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