llvm-6502/lib/Bitcode/Reader/Deserialize.cpp
Chris Lattner 962dde3cef Make a major API change to BitstreamReader: split all the reading
state out of the BitstreamReader class into a BitstreamCursor class.
Doing this allows the client to have multiple cursors into the same
file, each with potentially different live block stacks and
abbreviation records.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@70157 91177308-0d34-0410-b5e6-96231b3b80d8
2009-04-26 20:59:02 +00:00

455 lines
10 KiB
C++

//==- Deserialize.cpp - Generic Object Serialization to Bitcode --*- C++ -*-==//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the internal methods used for object serialization.
//
//===----------------------------------------------------------------------===//
#include "llvm/Bitcode/Deserialize.h"
#ifdef DEBUG_BACKPATCH
#include "llvm/Support/Streams.h"
#endif
using namespace llvm;
Deserializer::Deserializer(BitstreamReader& stream)
: Stream(stream), RecIdx(0), FreeList(NULL), AbbrevNo(0), RecordCode(0) {
StreamStart = Stream.GetCurrentBitNo();
}
Deserializer::~Deserializer() {
assert (RecIdx >= Record.size() &&
"Still scanning bitcode record when deserialization completed.");
#ifdef DEBUG_BACKPATCH
for (MapTy::iterator I=BPatchMap.begin(), E=BPatchMap.end(); I!=E; ++I)
assert (I->first.hasFinalPtr() &&
"Some pointers were not backpatched.");
#endif
}
bool Deserializer::inRecord() {
if (Record.size() > 0) {
if (RecIdx >= Record.size()) {
RecIdx = 0;
Record.clear();
AbbrevNo = 0;
return false;
}
else
return true;
}
return false;
}
bool Deserializer::AdvanceStream() {
assert (!inRecord() &&
"Cannot advance stream. Still processing a record.");
if (AbbrevNo == bitc::ENTER_SUBBLOCK ||
AbbrevNo >= bitc::UNABBREV_RECORD)
return true;
while (!Stream.AtEndOfStream()) {
uint64_t Pos = Stream.GetCurrentBitNo();
AbbrevNo = Stream.ReadCode();
switch (AbbrevNo) {
case bitc::ENTER_SUBBLOCK: {
unsigned id = Stream.ReadSubBlockID();
// Determine the extent of the block. This is useful for jumping around
// the stream. This is hack: we read the header of the block, save
// the length, and then revert the bitstream to a location just before
// the block is entered.
uint64_t BPos = Stream.GetCurrentBitNo();
Stream.ReadVBR(bitc::CodeLenWidth); // Skip the code size.
Stream.SkipToWord();
unsigned NumWords = Stream.Read(bitc::BlockSizeWidth);
Stream.JumpToBit(BPos);
BlockStack.push_back(Location(Pos,id,NumWords));
break;
}
case bitc::END_BLOCK: {
bool x = Stream.ReadBlockEnd();
assert(!x && "Error at block end."); x=x;
BlockStack.pop_back();
continue;
}
case bitc::DEFINE_ABBREV:
Stream.ReadAbbrevRecord();
continue;
default:
break;
}
return true;
}
return false;
}
void Deserializer::ReadRecord() {
while (AdvanceStream() && AbbrevNo == bitc::ENTER_SUBBLOCK) {
assert (!BlockStack.empty());
Stream.EnterSubBlock(BlockStack.back().BlockID);
AbbrevNo = 0;
}
if (Stream.AtEndOfStream())
return;
assert (Record.empty());
assert (AbbrevNo >= bitc::UNABBREV_RECORD);
RecordCode = Stream.ReadRecord(AbbrevNo,Record);
assert (Record.size() > 0);
}
void Deserializer::SkipBlock() {
assert (!inRecord());
if (AtEnd())
return;
AdvanceStream();
assert (AbbrevNo == bitc::ENTER_SUBBLOCK);
BlockStack.pop_back();
Stream.SkipBlock();
AbbrevNo = 0;
AdvanceStream();
}
bool Deserializer::SkipToBlock(unsigned BlockID) {
assert (!inRecord());
AdvanceStream();
assert (AbbrevNo == bitc::ENTER_SUBBLOCK);
unsigned BlockLevel = BlockStack.size();
while (!AtEnd() &&
BlockLevel == BlockStack.size() &&
getCurrentBlockID() != BlockID)
SkipBlock();
return !(AtEnd() || BlockLevel != BlockStack.size());
}
Deserializer::Location Deserializer::getCurrentBlockLocation() {
if (!inRecord())
AdvanceStream();
return BlockStack.back();
}
bool Deserializer::JumpTo(const Location& Loc) {
assert (!inRecord());
AdvanceStream();
assert (!BlockStack.empty() || AtEnd());
uint64_t LastBPos = StreamStart;
while (!BlockStack.empty()) {
LastBPos = BlockStack.back().BitNo;
// Determine of the current block contains the location of the block
// we are looking for.
if (BlockStack.back().contains(Loc)) {
// We found the enclosing block. We must first POP it off to
// destroy any accumulated context within the block scope. We then
// jump to the position of the block and enter it.
Stream.JumpToBit(LastBPos);
if (BlockStack.size() == Stream.BlockScope.size())
Stream.PopBlockScope();
BlockStack.pop_back();
AbbrevNo = 0;
AdvanceStream();
assert (AbbrevNo == bitc::ENTER_SUBBLOCK);
Stream.EnterSubBlock(BlockStack.back().BlockID);
break;
}
// This block does not contain the block we are looking for. Pop it.
if (BlockStack.size() == Stream.BlockScope.size())
Stream.PopBlockScope();
BlockStack.pop_back();
}
// Check if we have popped our way to the outermost scope. If so,
// we need to adjust our position.
if (BlockStack.empty()) {
assert (Stream.BlockScope.empty());
Stream.JumpToBit(Loc.BitNo < LastBPos ? StreamStart : LastBPos);
AbbrevNo = 0;
AdvanceStream();
}
assert (AbbrevNo == bitc::ENTER_SUBBLOCK);
assert (!BlockStack.empty());
while (!AtEnd() && BlockStack.back() != Loc) {
if (BlockStack.back().contains(Loc)) {
Stream.EnterSubBlock(BlockStack.back().BlockID);
AbbrevNo = 0;
AdvanceStream();
continue;
}
else
SkipBlock();
}
if (AtEnd())
return false;
assert (BlockStack.back() == Loc);
return true;
}
void Deserializer::Rewind() {
while (!Stream.BlockScope.empty())
Stream.PopBlockScope();
while (!BlockStack.empty())
BlockStack.pop_back();
Stream.JumpToBit(StreamStart);
AbbrevNo = 0;
}
unsigned Deserializer::getCurrentBlockID() {
if (!inRecord())
AdvanceStream();
return BlockStack.back().BlockID;
}
unsigned Deserializer::getRecordCode() {
if (!inRecord()) {
AdvanceStream();
assert (AbbrevNo >= bitc::UNABBREV_RECORD);
ReadRecord();
}
return RecordCode;
}
bool Deserializer::FinishedBlock(Location BlockLoc) {
if (!inRecord())
AdvanceStream();
for (llvm::SmallVector<Location,8>::reverse_iterator
I=BlockStack.rbegin(), E=BlockStack.rend(); I!=E; ++I)
if (*I == BlockLoc)
return false;
return true;
}
unsigned Deserializer::getAbbrevNo() {
if (!inRecord())
AdvanceStream();
return AbbrevNo;
}
bool Deserializer::AtEnd() {
if (inRecord())
return false;
if (!AdvanceStream())
return true;
return false;
}
uint64_t Deserializer::ReadInt() {
// FIXME: Any error recovery/handling with incomplete or bad files?
if (!inRecord())
ReadRecord();
return Record[RecIdx++];
}
int64_t Deserializer::ReadSInt() {
uint64_t x = ReadInt();
int64_t magnitude = x >> 1;
return x & 0x1 ? -magnitude : magnitude;
}
char* Deserializer::ReadCStr(char* cstr, unsigned MaxLen, bool isNullTerm) {
if (cstr == NULL)
MaxLen = 0; // Zero this just in case someone does something funny.
unsigned len = ReadInt();
assert (MaxLen == 0 || (len + (isNullTerm ? 1 : 0)) <= MaxLen);
if (!cstr)
cstr = new char[len + (isNullTerm ? 1 : 0)];
assert (cstr != NULL);
for (unsigned i = 0; i < len; ++i)
cstr[i] = (char) ReadInt();
if (isNullTerm)
cstr[len] = '\0';
return cstr;
}
void Deserializer::ReadCStr(std::vector<char>& buff, bool isNullTerm,
unsigned Idx) {
unsigned len = ReadInt();
// If Idx is beyond the current before size, reduce Idx to refer to the
// element after the last element.
if (Idx > buff.size())
Idx = buff.size();
buff.reserve(len+Idx);
buff.resize(Idx);
for (unsigned i = 0; i < len; ++i)
buff.push_back((char) ReadInt());
if (isNullTerm)
buff.push_back('\0');
}
void Deserializer::RegisterPtr(const SerializedPtrID& PtrId,
const void* Ptr) {
MapTy::value_type& E = BPatchMap.FindAndConstruct(BPKey(PtrId));
assert (!HasFinalPtr(E) && "Pointer already registered.");
#ifdef DEBUG_BACKPATCH
llvm::cerr << "RegisterPtr: " << PtrId << " => " << Ptr << "\n";
#endif
SetPtr(E,Ptr);
}
void Deserializer::ReadUIntPtr(uintptr_t& PtrRef,
const SerializedPtrID& PtrId,
bool AllowBackpatch) {
if (PtrId == 0) {
PtrRef = 0;
return;
}
MapTy::value_type& E = BPatchMap.FindAndConstruct(BPKey(PtrId));
if (HasFinalPtr(E)) {
PtrRef = GetFinalPtr(E);
#ifdef DEBUG_BACKPATCH
llvm::cerr << "ReadUintPtr: " << PtrId
<< " <-- " << (void*) GetFinalPtr(E) << '\n';
#endif
}
else {
assert (AllowBackpatch &&
"Client forbids backpatching for this pointer.");
#ifdef DEBUG_BACKPATCH
llvm::cerr << "ReadUintPtr: " << PtrId << " (NO PTR YET)\n";
#endif
// Register backpatch. Check the freelist for a BPNode.
BPNode* N;
if (FreeList) {
N = FreeList;
FreeList = FreeList->Next;
}
else // No available BPNode. Allocate one.
N = (BPNode*) Allocator.Allocate<BPNode>();
new (N) BPNode(GetBPNode(E),PtrRef);
SetBPNode(E,N);
}
}
uintptr_t Deserializer::ReadInternalRefPtr() {
SerializedPtrID PtrId = ReadPtrID();
assert (PtrId != 0 && "References cannot refer the NULL address.");
MapTy::value_type& E = BPatchMap.FindAndConstruct(BPKey(PtrId));
assert (HasFinalPtr(E) &&
"Cannot backpatch references. Object must be already deserialized.");
return GetFinalPtr(E);
}
void Deserializer::BPEntry::SetPtr(BPNode*& FreeList, void* P) {
BPNode* Last = NULL;
for (BPNode* N = Head; N != NULL; N=N->Next) {
Last = N;
N->PtrRef |= reinterpret_cast<uintptr_t>(P);
}
if (Last) {
Last->Next = FreeList;
FreeList = Head;
}
Ptr = const_cast<void*>(P);
}
#define INT_READ(TYPE)\
void SerializeTrait<TYPE>::Read(Deserializer& D, TYPE& X) {\
X = (TYPE) D.ReadInt(); }
INT_READ(bool)
INT_READ(unsigned char)
INT_READ(unsigned short)
INT_READ(unsigned int)
INT_READ(unsigned long)
#define SINT_READ(TYPE)\
void SerializeTrait<TYPE>::Read(Deserializer& D, TYPE& X) {\
X = (TYPE) D.ReadSInt(); }
INT_READ(signed char)
INT_READ(signed short)
INT_READ(signed int)
INT_READ(signed long)