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2edd22b959
llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
Chris Lattner 2edd22b959 Emit module-level constants. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@36384 91177308-0d34-0410-b5e6-96231b3b80d8
2007-04-24 00:16:04 +00:00

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//===--- Bitcode/Writer/Writer.cpp - Bitcode Writer -----------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by Chris Lattner and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Bitcode writer implementation.
//
//===----------------------------------------------------------------------===//
#include "llvm/Bitcode/ReaderWriter.h"
#include "llvm/Bitcode/BitstreamWriter.h"
#include "llvm/Bitcode/LLVMBitCodes.h"
#include "ValueEnumerator.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Module.h"
#include "llvm/TypeSymbolTable.h"
#include "llvm/ValueSymbolTable.h"
#include "llvm/Support/MathExtras.h"
using namespace llvm;
static const unsigned CurVersion = 0;
static void WriteStringRecord(unsigned Code, const std::string &Str,
unsigned AbbrevToUse, BitstreamWriter &Stream) {
SmallVector<unsigned, 64> Vals;
// Code: [strlen, strchar x N]
Vals.push_back(Str.size());
for (unsigned i = 0, e = Str.size(); i != e; ++i)
Vals.push_back(Str[i]);
// Emit the finished record.
Stream.EmitRecord(Code, Vals, AbbrevToUse);
}
/// WriteTypeTable - Write out the type table for a module.
static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
const ValueEnumerator::TypeList &TypeList = VE.getTypes();
Stream.EnterSubblock(bitc::TYPE_BLOCK_ID, 4 /*count from # abbrevs */);
SmallVector<uint64_t, 64> TypeVals;
// FIXME: Set up abbrevs now that we know the width of the type fields, etc.
// Emit an entry count so the reader can reserve space.
TypeVals.push_back(TypeList.size());
Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
TypeVals.clear();
// Loop over all of the types, emitting each in turn.
for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
const Type *T = TypeList[i].first;
int AbbrevToUse = 0;
unsigned Code = 0;
switch (T->getTypeID()) {
case Type::PackedStructTyID: // FIXME: Delete Type::PackedStructTyID.
default: assert(0 && "Unknown type!");
case Type::VoidTyID: Code = bitc::TYPE_CODE_VOID; break;
case Type::FloatTyID: Code = bitc::TYPE_CODE_FLOAT; break;
case Type::DoubleTyID: Code = bitc::TYPE_CODE_DOUBLE; break;
case Type::LabelTyID: Code = bitc::TYPE_CODE_LABEL; break;
case Type::OpaqueTyID: Code = bitc::TYPE_CODE_OPAQUE; break;
case Type::IntegerTyID:
// INTEGER: [width]
Code = bitc::TYPE_CODE_INTEGER;
TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
break;
case Type::PointerTyID:
// POINTER: [pointee type]
Code = bitc::TYPE_CODE_POINTER;
TypeVals.push_back(VE.getTypeID(cast<PointerType>(T)->getElementType()));
break;
case Type::FunctionTyID: {
const FunctionType *FT = cast<FunctionType>(T);
// FUNCTION: [isvararg, #pararms, paramty x N]
Code = bitc::TYPE_CODE_FUNCTION;
TypeVals.push_back(FT->isVarArg());
TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
// FIXME: PARAM ATTR ID!
TypeVals.push_back(FT->getNumParams());
for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
break;
}
case Type::StructTyID: {
const StructType *ST = cast<StructType>(T);
// STRUCT: [ispacked, #elts, eltty x N]
Code = bitc::TYPE_CODE_STRUCT;
TypeVals.push_back(ST->isPacked());
TypeVals.push_back(ST->getNumElements());
// Output all of the element types...
for (StructType::element_iterator I = ST->element_begin(),
E = ST->element_end(); I != E; ++I)
TypeVals.push_back(VE.getTypeID(*I));
break;
}
case Type::ArrayTyID: {
const ArrayType *AT = cast<ArrayType>(T);
// ARRAY: [numelts, eltty]
Code = bitc::TYPE_CODE_ARRAY;
TypeVals.push_back(AT->getNumElements());
TypeVals.push_back(VE.getTypeID(AT->getElementType()));
break;
}
case Type::VectorTyID: {
const VectorType *VT = cast<VectorType>(T);
// VECTOR [numelts, eltty]
Code = bitc::TYPE_CODE_VECTOR;
TypeVals.push_back(VT->getNumElements());
TypeVals.push_back(VE.getTypeID(VT->getElementType()));
break;
}
}
// Emit the finished record.
Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
TypeVals.clear();
}
Stream.ExitBlock();
}
static unsigned getEncodedLinkage(const GlobalValue *GV) {
switch (GV->getLinkage()) {
default: assert(0 && "Invalid linkage!");
case GlobalValue::ExternalLinkage: return 0;
case GlobalValue::WeakLinkage: return 1;
case GlobalValue::AppendingLinkage: return 2;
case GlobalValue::InternalLinkage: return 3;
case GlobalValue::LinkOnceLinkage: return 4;
case GlobalValue::DLLImportLinkage: return 5;
case GlobalValue::DLLExportLinkage: return 6;
case GlobalValue::ExternalWeakLinkage: return 7;
}
}
static unsigned getEncodedVisibility(const GlobalValue *GV) {
switch (GV->getVisibility()) {
default: assert(0 && "Invalid visibility!");
case GlobalValue::DefaultVisibility: return 0;
case GlobalValue::HiddenVisibility: return 1;
}
}
// Emit top-level description of module, including target triple, inline asm,
// descriptors for global variables, and function prototype info.
static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
BitstreamWriter &Stream) {
// Emit the list of dependent libraries for the Module.
for (Module::lib_iterator I = M->lib_begin(), E = M->lib_end(); I != E; ++I)
WriteStringRecord(bitc::MODULE_CODE_DEPLIB, *I, 0/*TODO*/, Stream);
// Emit various pieces of data attached to a module.
if (!M->getTargetTriple().empty())
WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
0/*TODO*/, Stream);
if (!M->getDataLayout().empty())
WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, M->getDataLayout(),
0/*TODO*/, Stream);
if (!M->getModuleInlineAsm().empty())
WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
0/*TODO*/, Stream);
// Emit information about sections, computing how many there are. Also
// compute the maximum alignment value.
std::map<std::string, unsigned> SectionMap;
unsigned MaxAlignment = 0;
unsigned MaxGlobalType = 0;
for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
GV != E; ++GV) {
MaxAlignment = std::max(MaxAlignment, GV->getAlignment());
MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV->getType()));
if (!GV->hasSection()) continue;
// Give section names unique ID's.
unsigned &Entry = SectionMap[GV->getSection()];
if (Entry != 0) continue;
WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV->getSection(),
0/*TODO*/, Stream);
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()];
if (Entry != 0) continue;
WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F->getSection(),
0/*TODO*/, Stream);
Entry = SectionMap.size();
}
// Emit abbrev for globals, now that we know # sections and max alignment.
unsigned SimpleGVarAbbrev = 0;
if (!M->global_empty()) {
// 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,
Log2_32_Ceil(MaxGlobalType+1)));
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+1)));
}
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()));
Vals.push_back(GV->isConstant());
Vals.push_back(GV->isDeclaration() ? 0 :
(VE.getValueID(GV->getInitializer()) + 1));
Vals.push_back(getEncodedLinkage(GV));
Vals.push_back(Log2_32(GV->getAlignment())+1);
Vals.push_back(GV->hasSection() ? SectionMap[GV->getSection()] : 0);
if (GV->isThreadLocal() ||
GV->getVisibility() != GlobalValue::DefaultVisibility) {
Vals.push_back(getEncodedVisibility(GV));
Vals.push_back(GV->isThreadLocal());
} else {
AbbrevToUse = SimpleGVarAbbrev;
}
Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
Vals.clear();
}
// Emit the function proto information.
for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
// FUNCTION: [type, callingconv, isproto, linkage, alignment, section,
// visibility]
Vals.push_back(VE.getTypeID(F->getType()));
Vals.push_back(F->getCallingConv());
Vals.push_back(F->isDeclaration());
Vals.push_back(getEncodedLinkage(F));
Vals.push_back(Log2_32(F->getAlignment())+1);
Vals.push_back(F->hasSection() ? SectionMap[F->getSection()] : 0);
Vals.push_back(getEncodedVisibility(F));
unsigned AbbrevToUse = 0;
Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
Vals.clear();
}
}
/// WriteTypeSymbolTable - Emit a block for the specified type symtab.
static void WriteTypeSymbolTable(const TypeSymbolTable &TST,
const ValueEnumerator &VE,
BitstreamWriter &Stream) {
if (TST.empty()) return;
Stream.EnterSubblock(bitc::TYPE_SYMTAB_BLOCK_ID, 3);
// FIXME: Set up the abbrev, we know how many types there are!
// FIXME: We know if the type names can use 7-bit ascii.
SmallVector<unsigned, 64> NameVals;
for (TypeSymbolTable::const_iterator TI = TST.begin(), TE = TST.end();
TI != TE; ++TI) {
unsigned AbbrevToUse = 0;
// TST_ENTRY: [typeid, namelen, namechar x N]
NameVals.push_back(VE.getTypeID(TI->second));
const std::string &Str = TI->first;
NameVals.push_back(Str.size());
for (unsigned i = 0, e = Str.size(); i != e; ++i)
NameVals.push_back(Str[i]);
// Emit the finished record.
Stream.EmitRecord(bitc::VST_CODE_ENTRY, NameVals, AbbrevToUse);
NameVals.clear();
}
Stream.ExitBlock();
}
// Emit names for globals/functions etc.
static void WriteValueSymbolTable(const ValueSymbolTable &VST,
const ValueEnumerator &VE,
BitstreamWriter &Stream) {
if (VST.empty()) return;
Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 3);
// FIXME: Set up the abbrev, we know how many values there are!
// FIXME: We know if the type names can use 7-bit ascii.
SmallVector<unsigned, 64> NameVals;
for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
SI != SE; ++SI) {
unsigned AbbrevToUse = 0;
// VST_ENTRY: [valueid, namelen, namechar x N]
NameVals.push_back(VE.getValueID(SI->getValue()));
NameVals.push_back(SI->getKeyLength());
for (const char *P = SI->getKeyData(),
*E = SI->getKeyData()+SI->getKeyLength(); P != E; ++P)
NameVals.push_back((unsigned char)*P);
// Emit the finished record.
Stream.EmitRecord(bitc::VST_CODE_ENTRY, NameVals, AbbrevToUse);
NameVals.clear();
}
Stream.ExitBlock();
}
static void WriteConstants(unsigned FirstVal, unsigned LastVal,
const ValueEnumerator &VE,
BitstreamWriter &Stream) {
if (FirstVal == LastVal) return;
Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 2);
// FIXME: Install and use abbrevs to reduce size.
SmallVector<uint64_t, 64> Record;
const ValueEnumerator::ValueList &Vals = VE.getValues();
const Type *LastTy = 0;
for (unsigned i = FirstVal; i != LastVal; ++i) {
const Value *V = Vals[i].first;
// If we need to switch types, do so now.
if (V->getType() != LastTy) {
LastTy = V->getType();
Record.push_back(VE.getTypeID(LastTy));
Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record);
Record.clear();
}
if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
assert(0 && IA && "FIXME: Inline asm writing unimp!");
continue;
}
const Constant *C = cast<Constant>(V);
unsigned Code = -1U;
unsigned AbbrevToUse = 0;
if (C->isNullValue()) {
Code = bitc::CST_CODE_NULL;
} else if (isa<UndefValue>(C)) {
Code = bitc::CST_CODE_UNDEF;
} else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
if (IV->getBitWidth() <= 64) {
int64_t V = IV->getSExtValue();
if (V >= 0)
Record.push_back(V << 1);
else
Record.push_back((-V << 1) | 1);
Code = bitc::CST_CODE_INTEGER;
} else { // Wide integers, > 64 bits in size.
// We have an arbitrary precision integer value to write whose
// bit width is > 64. However, in canonical unsigned integer
// format it is likely that the high bits are going to be zero.
// So, we only write the number of active words.
unsigned NWords = IV->getValue().getActiveWords();
const uint64_t *RawWords = IV->getValue().getRawData();
Record.push_back(NWords);
for (unsigned i = 0; i != NWords; ++i) {
int64_t V = RawWords[i];
if (V >= 0)
Record.push_back(V << 1);
else
Record.push_back((-V << 1) | 1);
}
Code = bitc::CST_CODE_WIDE_INTEGER;
}
} else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
Code = bitc::CST_CODE_FLOAT;
if (CFP->getType() == Type::FloatTy) {
Record.push_back(FloatToBits((float)CFP->getValue()));
} else {
assert (CFP->getType() == Type::DoubleTy && "Unknown FP type!");
Record.push_back(DoubleToBits((double)CFP->getValue()));
}
} else if (isa<ConstantArray>(C) || isa<ConstantStruct>(V) ||
isa<ConstantVector>(V)) {
Code = bitc::CST_CODE_AGGREGATE;
Record.push_back(C->getNumOperands());
for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
Record.push_back(VE.getValueID(C->getOperand(i)));
} else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
Code = bitc::CST_CODE_CONSTEXPR;
// FIXME: optimize for binops, compares, etc.
Record.push_back(CE->getOpcode());
Record.push_back(CE->getNumOperands());
for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i)
Record.push_back(VE.getValueID(C->getOperand(i)));
// Compares also pass their predicate.
if (CE->isCompare())
Record.push_back((unsigned)CE->getPredicate());
} else {
assert(0 && "Unknown constant!");
}
Stream.EmitRecord(Code, Record, AbbrevToUse);
Record.clear();
}
Stream.ExitBlock();
}
static void WriteModuleConstants(const ValueEnumerator &VE,
BitstreamWriter &Stream) {
const ValueEnumerator::ValueList &Vals = VE.getValues();
// Find the first constant to emit, which is the first non-globalvalue value.
// We know globalvalues have been emitted by WriteModuleInfo.
for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
if (!isa<GlobalValue>(Vals[i].first)) {
WriteConstants(i, Vals.size(), VE, Stream);
return;
}
}
}
/// WriteModule - Emit the specified module to the bitstream.
static void WriteModule(const Module *M, BitstreamWriter &Stream) {
Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
// Emit the version number if it is non-zero.
if (CurVersion) {
SmallVector<unsigned, 1> VersionVals;
VersionVals.push_back(CurVersion);
Stream.EmitRecord(bitc::MODULE_CODE_VERSION, VersionVals);
}
// Analyze the module, enumerating globals, functions, etc.
ValueEnumerator VE(M);
// Emit information describing all of the types in the module.
WriteTypeTable(VE, Stream);
// Emit top-level description of module, including target triple, inline asm,
// descriptors for global variables, and function prototype info.
WriteModuleInfo(M, VE, Stream);
// Emit constants.
WriteModuleConstants(VE, Stream);
// Emit the type symbol table information.
WriteTypeSymbolTable(M->getTypeSymbolTable(), VE, Stream);
// Emit names for globals/functions etc.
WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
Stream.ExitBlock();
}
/// WriteBitcodeToFile - Write the specified module to the specified output
/// stream.
void llvm::WriteBitcodeToFile(const Module *M, std::ostream &Out) {
std::vector<unsigned char> Buffer;
BitstreamWriter Stream(Buffer);
Buffer.reserve(256*1024);
// Emit the file header.
Stream.Emit((unsigned)'B', 8);
Stream.Emit((unsigned)'C', 8);
Stream.Emit(0x0, 4);
Stream.Emit(0xC, 4);
Stream.Emit(0xE, 4);
Stream.Emit(0xD, 4);
// Emit the module.
WriteModule(M, Stream);
// Write the generated bitstream to "Out".
Out.write((char*)&Buffer.front(), Buffer.size());
}
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