llvm-6502/lib/Bytecode/Reader/Reader.cpp

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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: Make error message outputs be configurable depending on an option?
// TODO: Allow passing in an option to ignore the symbol table
//
//===------------------------------------------------------------------------===
#include "llvm/Bytecode/Reader.h"
#include "llvm/Bytecode/Format.h"
#include "llvm/Module.h"
#include "llvm/BasicBlock.h"
#include "llvm/DerivedTypes.h"
#include "llvm/ConstPoolVals.h"
#include "llvm/iOther.h"
#include "ReaderInternals.h"
#include <sys/types.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <algorithm>
bool BytecodeParser::getTypeSlot(const Type *Ty, unsigned &Slot) {
if (Ty->isPrimitiveType()) {
Slot = Ty->getPrimitiveID();
} else {
TypeMapType::iterator I = TypeMap.find(Ty);
if (I == TypeMap.end()) return true; // Didn't find type!
Slot = I->second;
}
//cerr << "getTypeSlot '" << Ty->getName() << "' = " << Slot << endl;
return false;
}
const Type *BytecodeParser::getType(unsigned ID) {
const Type *T = Type::getPrimitiveType((Type::PrimitiveID)ID);
if (T) return T;
//cerr << "Looking up Type ID: " << ID << endl;
const Value *D = getValue(Type::TypeTy, ID, false);
if (D == 0) return 0;
assert(D->getType() == Type::TypeTy &&
D->getValueType() == Value::ConstantVal);
return ((const ConstPoolType*)D)->getValue();;
}
bool BytecodeParser::insertValue(Value *Def, vector<ValueList> &ValueTab) {
unsigned type;
if (getTypeSlot(Def->getType(), type)) return true;
if (ValueTab.size() <= type)
ValueTab.resize(type+1, ValueList());
//cerr << "insertValue Values[" << type << "][" << ValueTab[type].size()
// << "] = " << Def << endl;
if (type == Type::TypeTyID && Def->getValueType() == Value::ConstantVal) {
const Type *Ty = ((const ConstPoolType*)Def)->getValue();
unsigned ValueOffset = FirstDerivedTyID;
if (&ValueTab == &Values) // Take into consideration module level types
ValueOffset += ModuleValues[type].size();
if (TypeMap.find(Ty) == TypeMap.end())
TypeMap[Ty] = ValueTab[type].size()+ValueOffset;
}
ValueTab[type].push_back(Def);
return false;
}
Value *BytecodeParser::getValue(const Type *Ty, unsigned oNum, bool Create) {
unsigned Num = oNum;
unsigned type; // The type plane it lives in...
if (getTypeSlot(Ty, type)) return 0; // TODO: true
if (type == Type::TypeTyID) { // The 'type' plane has implicit values
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;
}
if (ModuleValues.size() > type) {
if (ModuleValues[type].size() > Num)
return ModuleValues[type][Num];
Num -= ModuleValues[type].size();
}
if (Values.size() > type && Values[type].size() > Num)
return Values[type][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;
case Type::MethodTyID:
cerr << "Creating method pholder! : " << type << ":" << oNum << " "
<< Ty->getName() << endl;
d = new MethPHolder(Ty, oNum);
insertValue(d, LateResolveModuleValues);
return d;
default: d = new DefPHolder(Ty, oNum); break;
}
assert(d != 0 && "How did we not make something?");
if (insertValue(d, LateResolveValues)) return 0;
return d;
}
bool BytecodeParser::postResolveValues(ValueTable &ValTab) {
bool Error = false;
for (unsigned ty = 0; ty < ValTab.size(); ty++) {
ValueList &DL = ValTab[ty];
unsigned Size;
while ((Size = DL.size())) {
unsigned IDNumber = getValueIDNumberFromPlaceHolder(DL[Size-1]);
Value *D = DL[Size-1];
DL.pop_back();
Value *NewDef = getValue(D->getType(), IDNumber, false);
if (NewDef == 0) {
Error = true; // Unresolved thinger
cerr << "Unresolvable reference found: <" << D->getType()->getName()
<< ">:" << IDNumber << "!\n";
} 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!
}
}
}
return Error;
}
bool BytecodeParser::ParseBasicBlock(const uchar *&Buf, const uchar *EndBuf,
BasicBlock *&BB) {
BB = new BasicBlock();
while (Buf < EndBuf) {
Instruction *Def;
if (ParseInstruction(Buf, EndBuf, Def)) {
delete BB;
return true;
}
if (Def == 0) { delete BB; return true; }
if (insertValue(Def, Values)) { delete BB; return true; }
BB->getInstList().push_back(Def);
}
return false;
}
bool BytecodeParser::ParseSymbolTable(const uchar *&Buf, const uchar *EndBuf) {
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)) return true;
const Type *Ty = getType(Typ);
if (Ty == 0) return true;
for (unsigned i = 0; i < NumEntries; i++) {
// Symtab entry: [def slot #][name]
unsigned slot;
if (read_vbr(Buf, EndBuf, slot)) return true;
string Name;
if (read(Buf, EndBuf, Name, false)) // Not aligned...
return true;
Value *D = getValue(Ty, slot, false); // Find mapping...
if (D == 0) return true;
D->setName(Name);
}
}
return Buf > EndBuf;
}
bool BytecodeParser::ParseMethod(const uchar *&Buf, const uchar *EndBuf,
Module *C) {
// Clear out the local values table...
Values.clear();
if (MethodSignatureList.empty()) return true; // Unexpected method!
const MethodType *MTy = MethodSignatureList.front().first;
unsigned MethSlot = MethodSignatureList.front().second;
MethodSignatureList.pop_front();
Method *M = new Method(MTy);
const MethodType::ParamTypes &Params = MTy->getParamTypes();
for (MethodType::ParamTypes::const_iterator It = Params.begin();
It != Params.end(); It++) {
MethodArgument *MA = new MethodArgument(*It);
if (insertValue(MA, Values)) { delete M; return true; }
M->getArgumentList().push_back(MA);
}
while (Buf < EndBuf) {
unsigned Type, Size;
const uchar *OldBuf = Buf;
if (readBlock(Buf, EndBuf, Type, Size)) { delete M; return true; }
switch (Type) {
case BytecodeFormat::ConstantPool:
if (ParseConstantPool(Buf, Buf+Size, M->getConstantPool(), Values)) {
cerr << "Error reading constant pool!\n";
delete M; return true;
}
break;
case BytecodeFormat::BasicBlock: {
BasicBlock *BB;
if (ParseBasicBlock(Buf, Buf+Size, BB) ||
insertValue(BB, Values)) {
cerr << "Error parsing basic block!\n";
delete M; return true; // Parse error... :(
}
M->getBasicBlocks().push_back(BB);
break;
}
case BytecodeFormat::SymbolTable:
if (ParseSymbolTable(Buf, Buf+Size)) {
cerr << "Error reading method symbol table!\n";
delete M; return true;
}
break;
default:
Buf += Size;
if (OldBuf > Buf) return true; // Wrap around!
break;
}
if (align32(Buf, EndBuf)) {
delete M; // Malformed bc file, read past end of block.
return true;
}
}
if (postResolveValues(LateResolveValues) ||
postResolveValues(LateResolveModuleValues)) {
delete M; return true; // Unresolvable references!
}
Value *MethPHolder = getValue(MTy, MethSlot, false);
assert(MethPHolder && "Something is broken no placeholder found!");
assert(MethPHolder->getValueType() == Value::MethodVal && "Not a method?");
unsigned type; // Type slot
assert(!getTypeSlot(MTy, type) && "How can meth type not exist?");
getTypeSlot(MTy, type);
C->getMethodList().push_back(M);
// Replace placeholder with the real method pointer...
ModuleValues[type][MethSlot] = M;
// If anyone is using the placeholder make them use the real method instead
MethPHolder->replaceAllUsesWith(M);
// We don't need the placeholder anymore!
delete MethPHolder;
return false;
}
bool BytecodeParser::ParseModuleGlobalInfo(const uchar *&Buf, const uchar *End,
Module *C) {
if (!MethodSignatureList.empty()) return true; // Two ModuleGlobal blocks?
// Read the method signatures for all of the methods that are coming, and
// create fillers in the Value tables.
unsigned MethSignature;
if (read_vbr(Buf, End, MethSignature)) return true;
while (MethSignature != Type::VoidTyID) { // List is terminated by Void
const Type *Ty = getType(MethSignature);
if (!Ty || !Ty->isMethodType()) {
cerr << "Method not meth type! ";
if (Ty) cerr << Ty->getName(); else cerr << MethSignature; cerr << endl;
return true;
}
// When the ModuleGlobalInfo section is read, we load the type of each method
// and the 'ModuleValues' slot that it lands in. We then load a placeholder
// into its slot to reserve it. When the method is loaded, this placeholder
// is replaced.
// Insert the placeholder...
Value *Def = new MethPHolder(Ty, 0);
insertValue(Def, ModuleValues);
// Figure out which entry of its typeslot it went into...
unsigned TypeSlot;
if (getTypeSlot(Def->getType(), TypeSlot)) return true;
unsigned SlotNo = ModuleValues[TypeSlot].size()-1;
// Keep track of this information in a linked list that is emptied as
// methods are loaded...
//
MethodSignatureList.push_back(make_pair((const MethodType*)Ty, SlotNo));
if (read_vbr(Buf, End, MethSignature)) return true;
}
if (align32(Buf, End)) return true;
// 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;
return false;
}
bool BytecodeParser::ParseModule(const uchar *Buf, const uchar *EndBuf,
Module *&C) {
unsigned Type, Size;
if (readBlock(Buf, EndBuf, Type, Size)) return true;
if (Type != BytecodeFormat::Module || Buf+Size != EndBuf)
return true; // Hrm, not a class?
MethodSignatureList.clear(); // Just in case...
// Read into instance variables...
if (read_vbr(Buf, EndBuf, FirstDerivedTyID)) return true;
if (align32(Buf, EndBuf)) return true;
C = new Module();
while (Buf < EndBuf) {
const uchar *OldBuf = Buf;
if (readBlock(Buf, EndBuf, Type, Size)) { delete C; return true; }
switch (Type) {
case BytecodeFormat::ModuleGlobalInfo:
if (ParseModuleGlobalInfo(Buf, Buf+Size, C)) {
cerr << "Error reading class global info section!\n";
delete C; return true;
}
break;
case BytecodeFormat::ConstantPool:
if (ParseConstantPool(Buf, Buf+Size, C->getConstantPool(), ModuleValues)) {
cerr << "Error reading class constant pool!\n";
delete C; return true;
}
break;
case BytecodeFormat::Method: {
if (ParseMethod(Buf, Buf+Size, C)) {
delete C; return true; // Error parsing method
}
break;
}
case BytecodeFormat::SymbolTable:
if (ParseSymbolTable(Buf, Buf+Size)) {
cerr << "Error reading class symbol table!\n";
delete C; return true;
}
break;
default:
cerr << "Unknown class block: " << Type << endl;
Buf += Size;
if (OldBuf > Buf) return true; // Wrap around!
break;
}
if (align32(Buf, EndBuf)) { delete C; return true; }
}
if (!MethodSignatureList.empty()) // Expected more methods!
return true;
return false;
}
Module *BytecodeParser::ParseBytecode(const uchar *Buf, const uchar *EndBuf) {
LateResolveValues.clear();
unsigned Sig;
// Read and check signature...
if (read(Buf, EndBuf, Sig) ||
Sig != ('l' | ('l' << 8) | ('v' << 16) | 'm' << 24))
return 0; // Invalid signature!
Module *Result;
if (ParseModule(Buf, EndBuf, Result)) return 0;
return Result;
}
Module *ParseBytecodeBuffer(const uchar *Buffer, unsigned Length) {
BytecodeParser Parser;
return Parser.ParseBytecode(Buffer, Buffer+Length);
}
// Parse and return a class file...
//
Module *ParseBytecodeFile(const string &Filename) {
struct stat StatBuf;
Module *Result = 0;
if (Filename != string("-")) { // Read from a file...
int FD = open(Filename.data(), O_RDONLY);
if (FD == -1) return 0;
if (fstat(FD, &StatBuf) == -1) { close(FD); return 0; }
int Length = StatBuf.st_size;
if (Length == 0) { close(FD); return 0; }
uchar *Buffer = (uchar*)mmap(0, Length, PROT_READ,
MAP_PRIVATE, FD, 0);
if (Buffer == (uchar*)-1) { close(FD); return 0; }
BytecodeParser Parser;
Result = Parser.ParseBytecode(Buffer, Buffer+Length);
munmap((char*)Buffer, Length);
close(FD);
} else { // Read from stdin
size_t FileSize = 0;
int BlockSize;
uchar Buffer[4096], *FileData = 0;
while ((BlockSize = read(0, Buffer, 4))) {
if (BlockSize == -1) { free(FileData); return 0; }
FileData = (uchar*)realloc(FileData, FileSize+BlockSize);
memcpy(FileData+FileSize, Buffer, BlockSize);
FileSize += BlockSize;
}
if (FileSize == 0) { free(FileData); return 0; }
#define ALIGN_PTRS 1
#if ALIGN_PTRS
uchar *Buf = (uchar*)mmap(0, FileSize, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
assert((Buf != (uchar*)-1) && "mmap returned error!");
free(FileData);
memcpy(Buf, FileData, FileSize);
#else
uchar *Buf = FileData;
#endif
BytecodeParser Parser;
Result = Parser.ParseBytecode(Buf, Buf+FileSize);
#if ALIGN_PTRS
munmap((char*)Buf, FileSize); // Free mmap'd data area
#else
free(FileData); // Free realloc'd block of memory
#endif
}
return Result;
}