first part of implementation of abbrevs. The writer isn't fully there yet and the

reader doesn't handle them at all yet.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@36363 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2007-04-23 16:04:05 +00:00
parent a18b965752
commit 36d5e7d31b
5 changed files with 156 additions and 25 deletions

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@ -18,6 +18,10 @@
#ifndef LLVM_BITCODE_BITCODES_H
#define LLVM_BITCODE_BITCODES_H
#include "llvm/ADT/SmallVector.h"
#include "llvm/Support/DataTypes.h"
#include <cassert>
namespace llvm {
namespace bitc {
enum StandardWidths {
@ -31,16 +35,71 @@ namespace bitc {
enum FixedCodes {
END_BLOCK = 0, // Must be zero to guarantee termination for broken bitcode.
ENTER_SUBBLOCK = 1,
/// DEFINE_ABBREV - Defines an abbrev for the current block. It consists
/// of a vbr5 for # operand infos. Each operand info is emitted with a
/// single bit to indicate if it is a literal encoding. If so, the value is
/// emitted with a vbr8. If not, the encoding is emitted as 3 bits followed
/// by the info value as a vbr5 if needed.
DEFINE_ABBREV = 2,
// Two codes are reserved for defining abbrevs and for emitting an
// unabbreviated record.
DEFINE_ABBREVS = 2,
// UNABBREV_RECORDs are emitted with a vbr6 for the record code, followed by
// a vbr6 for the # operands, followed by vbr6's for each operand.
UNABBREV_RECORD = 3,
// This is not a code, this is a marker for the first abbrev assignment.
FIRST_ABBREV = 4
};
} // End bitc namespace
/// BitCodeAbbrevOp - This describes one or more operands in an abbreviation.
/// This is actually a union of two different things:
/// 1. It could be a literal integer value ("the operand is always 17").
/// 2. It could be an encoding specification ("this operand encoded like so").
///
class BitCodeAbbrevOp {
uint64_t Val; // A literal value or data for an encoding.
bool IsLiteral : 1; // Indicate whether this is a literal value or not.
unsigned Enc : 3; // The encoding to use.
public:
enum Encoding {
FixedWidth = 1, // A fixed with field, Val specifies number of bits.
VBR = 2 // A VBR field where Val specifies the width of each chunk.
};
BitCodeAbbrevOp(uint64_t V) : Val(V), IsLiteral(true) {}
BitCodeAbbrevOp(Encoding E, uint64_t Data)
: Val(Data), IsLiteral(false), Enc(E) {}
bool isLiteral() const { return IsLiteral; }
bool isEncoding() const { return !IsLiteral; }
// Accessors for literals.
uint64_t getLiteralValue() const { assert(isLiteral()); return Val; }
// Accessors for encoding info.
Encoding getEncoding() const { assert(isEncoding()); return (Encoding)Enc; }
uint64_t getEncodingData() const { assert(isEncoding()); return Val; }
bool hasEncodingData() const { return hasEncodingData(getEncoding()); }
static bool hasEncodingData(Encoding E) {
return true;
}
};
class BitCodeAbbrev {
SmallVector<BitCodeAbbrevOp, 8> OperandList;
public:
unsigned getNumOperandInfos() const { return OperandList.size(); }
const BitCodeAbbrevOp &getOperandInfo(unsigned N) const {
return OperandList[N];
}
void Add(const BitCodeAbbrevOp &OpInfo) {
OperandList.push_back(OpInfo);
}
};
} // End llvm namespace
#endif

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@ -16,9 +16,6 @@
#define BITSTREAM_READER_H
#include "llvm/Bitcode/BitCodes.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Support/DataTypes.h"
#include <cassert>
namespace llvm {

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@ -16,9 +16,6 @@
#define BITSTREAM_WRITER_H
#include "llvm/Bitcode/BitCodes.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Support/DataTypes.h"
#include <cassert>
#include <vector>
namespace llvm {
@ -39,11 +36,14 @@ class BitstreamWriter {
struct Block {
unsigned PrevCodeSize;
unsigned StartSizeWord;
std::vector<BitCodeAbbrev*> PrevAbbrevs;
Block(unsigned PCS, unsigned SSW) : PrevCodeSize(PCS), StartSizeWord(SSW) {}
};
/// BlockScope - This tracks the current blocks that we have entered.
std::vector<Block> BlockScope;
std::vector<BitCodeAbbrev*> CurAbbrevs;
public:
BitstreamWriter(std::vector<unsigned char> &O)
: Out(O), CurBit(0), CurValue(0), CurCodeSize(2) {}
@ -145,6 +145,12 @@ public:
EmitVBR(CodeLen, bitc::CodeLenWidth);
FlushToWord();
BlockScope.push_back(Block(CurCodeSize, Out.size()/4));
// Delete all abbrevs.
for (unsigned i = 0, e = CurAbbrevs.size(); i != e; ++i)
delete CurAbbrevs[i];
BlockScope.back().PrevAbbrevs.swap(CurAbbrevs);
// Emit a placeholder, which will be replaced when the block is popped.
Emit(0, bitc::BlockSizeWidth);
@ -153,8 +159,7 @@ public:
void ExitBlock() {
assert(!BlockScope.empty() && "Block scope imbalance!");
Block B = BlockScope.back();
BlockScope.pop_back();
const Block &B = BlockScope.back();
// Block tail:
// [END_BLOCK, <align4bytes>]
@ -171,8 +176,10 @@ public:
Out[ByteNo++] = (unsigned char)(SizeInWords >> 16);
Out[ByteNo++] = (unsigned char)(SizeInWords >> 24);
// Restore the outer block's code size.
// Restore the inner block's code size and abbrev table.
CurCodeSize = B.PrevCodeSize;
BlockScope.back().PrevAbbrevs.swap(CurAbbrevs);
BlockScope.pop_back();
}
//===--------------------------------------------------------------------===//
@ -184,7 +191,14 @@ public:
void EmitRecord(unsigned Code, SmallVectorImpl<uint64_t> &Vals,
unsigned Abbrev = 0) {
if (Abbrev) {
assert(0 && "abbrevs not implemented yet!");
unsigned AbbrevNo = Abbrev-bitc::FIRST_ABBREV;
assert(AbbrevNo < CurAbbrevs.size() && "Invalid abbrev #!");
BitCodeAbbrev *Abbv = CurAbbrevs[AbbrevNo];
assert(0 && "TODO");
for (unsigned i = 0, e = Abbv->getNumOperandInfos(); i != e; ++i) {
}
} else {
// If we don't have an abbrev to use, emit this in its fully unabbreviated
// form.
@ -212,6 +226,32 @@ public:
EmitVBR(Vals[i], 6);
}
}
//===--------------------------------------------------------------------===//
// Abbrev Emission
//===--------------------------------------------------------------------===//
/// EmitAbbrev - This emits an abbreviation to the stream. Note that this
/// method takes ownership of the specified abbrev.
unsigned EmitAbbrev(BitCodeAbbrev *Abbv) {
// Emit the abbreviation as a record.
EmitCode(bitc::DEFINE_ABBREV);
EmitVBR(Abbv->getNumOperandInfos(), 5);
for (unsigned i = 0, e = Abbv->getNumOperandInfos(); i != e; ++i) {
const BitCodeAbbrevOp &Op = Abbv->getOperandInfo(i);
Emit(Op.isLiteral(), 1);
if (Op.isLiteral()) {
EmitVBR64(Op.getLiteralValue(), 8);
} else {
Emit(Op.getEncoding(), 3);
if (Op.hasEncodingData())
EmitVBR64(Op.getEncodingData(), 5);
}
}
CurAbbrevs.push_back(Abbv);
return CurAbbrevs.size()-1+bitc::FIRST_ABBREV;
}
};

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@ -93,7 +93,7 @@ bool BitcodeReader::ParseTypeTable(BitstreamReader &Stream) {
continue;
}
if (Code == bitc::DEFINE_ABBREVS) {
if (Code == bitc::DEFINE_ABBREV) {
assert(0 && "Abbrevs not implemented yet!");
}
@ -230,7 +230,7 @@ bool BitcodeReader::ParseTypeSymbolTable(BitstreamReader &Stream) {
continue;
}
if (Code == bitc::DEFINE_ABBREVS) {
if (Code == bitc::DEFINE_ABBREV) {
assert(0 && "Abbrevs not implemented yet!");
}
@ -293,7 +293,7 @@ bool BitcodeReader::ParseModule(BitstreamReader &Stream,
continue;
}
if (Code == bitc::DEFINE_ABBREVS) {
if (Code == bitc::DEFINE_ABBREV) {
assert(0 && "Abbrevs not implemented yet!");
}
@ -345,7 +345,7 @@ bool BitcodeReader::ParseModule(BitstreamReader &Stream,
// GLOBALVAR: [type, isconst, initid,
// linkage, alignment, section, visibility, threadlocal]
case bitc::MODULE_CODE_GLOBALVAR: {
if (Record.size() < 8)
if (Record.size() < 6)
return Error("Invalid MODULE_CODE_GLOBALVAR record");
const Type *Ty = getTypeByID(Record[0]);
if (!isa<PointerType>(Ty))
@ -361,8 +361,10 @@ bool BitcodeReader::ParseModule(BitstreamReader &Stream,
return Error("Invalid section ID");
Section = SectionTable[Record[5]-1];
}
GlobalValue::VisibilityTypes Visibility = GetDecodedVisibility(Record[6]);
bool isThreadLocal = Record[7];
GlobalValue::VisibilityTypes Visibility = GlobalValue::DefaultVisibility;
if (Record.size() >= 6) Visibility = GetDecodedVisibility(Record[6]);
bool isThreadLocal = false;
if (Record.size() >= 7) isThreadLocal = Record[7];
GlobalVariable *NewGV =
new GlobalVariable(Ty, isConstant, Linkage, 0, "", TheModule);

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@ -200,10 +200,14 @@ static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
0/*TODO*/, Stream);
// Emit information about sections.
// Emit information about sections, computing how many there are. Also
// compute the maximum alignment value.
std::map<std::string, unsigned> SectionMap;
unsigned MaxAlignment = 0;
for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
GV != E; ++GV) {
MaxAlignment = std::max(MaxAlignment, GV->getAlignment());
if (!GV->hasSection()) continue;
// Give section names unique ID's.
unsigned &Entry = SectionMap[GV->getSection()];
@ -213,6 +217,7 @@ static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
Entry = SectionMap.size();
}
for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
MaxAlignment = std::max(MaxAlignment, F->getAlignment());
if (!F->hasSection()) continue;
// Give section names unique ID's.
unsigned &Entry = SectionMap[F->getSection()];
@ -222,13 +227,37 @@ static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
Entry = SectionMap.size();
}
// TODO: Emit abbrev, now that we know # sections.
// Emit abbrev for globals, now that we know # sections and max alignment.
unsigned SimpleGVarAbbrev = 0;
if (!M->global_empty() && 0) {
// Add an abbrev for common globals with no visibility or thread localness.
BitCodeAbbrev *Abbv = new BitCodeAbbrev();
Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::FixedWidth, 1)); // Constant.
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Initializer.
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::FixedWidth, 3)); // Linkage.
if (MaxAlignment == 0) // Alignment.
Abbv->Add(BitCodeAbbrevOp(0));
else {
unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::FixedWidth,
Log2_32_Ceil(MaxEncAlignment)));
}
if (SectionMap.empty()) // Section.
Abbv->Add(BitCodeAbbrevOp(0));
else
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::FixedWidth,
Log2_32_Ceil(SectionMap.size())));
// Don't bother emitting vis + thread local.
SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
}
// Emit the global variable information.
SmallVector<unsigned, 64> Vals;
for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
GV != E; ++GV) {
unsigned AbbrevToUse = 0;
// GLOBALVAR: [type, isconst, initid,
// linkage, alignment, section, visibility, threadlocal]
Vals.push_back(VE.getTypeID(GV->getType()));
@ -238,10 +267,14 @@ static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
Vals.push_back(getEncodedLinkage(GV));
Vals.push_back(Log2_32(GV->getAlignment())+1);
Vals.push_back(GV->hasSection() ? SectionMap[GV->getSection()] : 0);
Vals.push_back(getEncodedVisibility(GV));
Vals.push_back(GV->isThreadLocal());
if (GV->isThreadLocal() ||
GV->getVisibility() != GlobalValue::DefaultVisibility) {
Vals.push_back(getEncodedVisibility(GV));
Vals.push_back(GV->isThreadLocal());
} else {
AbbrevToUse = SimpleGVarAbbrev;
}
unsigned AbbrevToUse = 0;
Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
Vals.clear();
}