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//===- ReadInst.cpp - Code to read an instruction from bytecode -------------===
//
// This file defines the mechanism to read an instruction from a bytecode
// stream.
//
// Note that this library should be as fast as possible, reentrant, and
// threadsafe!!
//
// TODO: Change from getValue(Raw.Arg1) etc, to getArg(Raw, 1)
// Make it check type, so that casts are checked.
//
//===------------------------------------------------------------------------===
#include "llvm/iOther.h"
#include "llvm/iTerminators.h"
#include "llvm/iMemory.h"
#include "llvm/DerivedTypes.h"
#include "ReaderInternals.h"
bool BytecodeParser::ParseRawInst(const uchar *&Buf, const uchar *EndBuf,
RawInst &Result) {
unsigned Op, Typ;
if (read(Buf, EndBuf, Op)) return true;
Result.NumOperands = Op >> 30;
Result.Opcode = (Op >> 24) & 63;
switch (Result.NumOperands) {
case 1:
Result.Ty = getType((Op >> 12) & 4095);
Result.Arg1 = Op & 4095;
if (Result.Arg1 == 4095) // Handle special encoding for 0 operands...
Result.NumOperands = 0;
break;
case 2:
Result.Ty = getType((Op >> 16) & 255);
Result.Arg1 = (Op >> 8 ) & 255;
Result.Arg2 = (Op >> 0 ) & 255;
break;
case 3:
Result.Ty = getType((Op >> 18) & 63);
Result.Arg1 = (Op >> 12) & 63;
Result.Arg2 = (Op >> 6 ) & 63;
Result.Arg3 = (Op >> 0 ) & 63;
break;
case 0:
Buf -= 4; // Hrm, try this again...
if (read_vbr(Buf, EndBuf, Result.Opcode)) return true;
if (read_vbr(Buf, EndBuf, Typ)) return true;
Result.Ty = getType(Typ);
if (read_vbr(Buf, EndBuf, Result.NumOperands)) return true;
switch (Result.NumOperands) {
case 0:
cerr << "Zero Arg instr found!\n";
return true; // This encoding is invalid!
case 1:
if (read_vbr(Buf, EndBuf, Result.Arg1)) return true;
break;
case 2:
if (read_vbr(Buf, EndBuf, Result.Arg1) ||
read_vbr(Buf, EndBuf, Result.Arg2)) return true;
break;
case 3:
if (read_vbr(Buf, EndBuf, Result.Arg1) ||
read_vbr(Buf, EndBuf, Result.Arg2) ||
read_vbr(Buf, EndBuf, Result.Arg3)) return true;
break;
default:
if (read_vbr(Buf, EndBuf, Result.Arg1) ||
read_vbr(Buf, EndBuf, Result.Arg2)) return true;
// Allocate a vector to hold arguments 3, 4, 5, 6 ...
Result.VarArgs = new vector<unsigned>(Result.NumOperands-2);
for (unsigned a = 0; a < Result.NumOperands-2; a++)
if (read_vbr(Buf, EndBuf, (*Result.VarArgs)[a])) return true;
break;
}
if (align32(Buf, EndBuf)) return true;
break;
}
//cerr << "NO: " << Result.NumOperands << " opcode: " << Result.Opcode
// << " Ty: " << Result.Ty->getName() << " arg1: " << Result.Arg1 << endl;
return false;
}
bool BytecodeParser::ParseInstruction(const uchar *&Buf, const uchar *EndBuf,
Instruction *&Res) {
RawInst Raw;
if (ParseRawInst(Buf, EndBuf, Raw)) return true;;
if (Raw.Opcode >= Instruction::FirstUnaryOp &&
Raw.Opcode < Instruction::NumUnaryOps && Raw.NumOperands == 1) {
Res = Instruction::getUnaryOperator(Raw.Opcode, getValue(Raw.Ty, Raw.Arg1));
return false;
} else if (Raw.Opcode >= Instruction::FirstBinaryOp &&
Raw.Opcode < Instruction::NumBinaryOps && Raw.NumOperands == 2) {
Res = Instruction::getBinaryOperator(Raw.Opcode, getValue(Raw.Ty, Raw.Arg1),
getValue(Raw.Ty, Raw.Arg2));
return false;
} else if (Raw.Opcode == Instruction::PHINode) {
PHINode *PN = new PHINode(Raw.Ty);
switch (Raw.NumOperands) {
case 0: cerr << "Invalid phi node encountered!\n";
delete PN;
return true;
case 1: PN->addIncoming(getValue(Raw.Ty, Raw.Arg1)); break;
case 2: PN->addIncoming(getValue(Raw.Ty, Raw.Arg1));
PN->addIncoming(getValue(Raw.Ty, Raw.Arg2)); break;
case 3: PN->addIncoming(getValue(Raw.Ty, Raw.Arg1));
PN->addIncoming(getValue(Raw.Ty, Raw.Arg2));
PN->addIncoming(getValue(Raw.Ty, Raw.Arg3)); break;
default:
PN->addIncoming(getValue(Raw.Ty, Raw.Arg1));
PN->addIncoming(getValue(Raw.Ty, Raw.Arg2));
{
vector<unsigned> &args = *Raw.VarArgs;
for (unsigned i = 0; i < args.size(); i++)
PN->addIncoming(getValue(Raw.Ty, args[i]));
}
delete Raw.VarArgs;
}
Res = PN;
return false;
} else if (Raw.Opcode == Instruction::Ret) {
if (Raw.NumOperands == 0) {
Res = new ReturnInst(); return false;
} else if (Raw.NumOperands == 1) {
Res = new ReturnInst(getValue(Raw.Ty, Raw.Arg1)); return false;
}
} else if (Raw.Opcode == Instruction::Br) {
if (Raw.NumOperands == 1) {
Res = new BranchInst((BasicBlock*)getValue(Type::LabelTy, Raw.Arg1));
return false;
} else if (Raw.NumOperands == 3) {
Res = new BranchInst((BasicBlock*)getValue(Type::LabelTy, Raw.Arg1),
(BasicBlock*)getValue(Type::LabelTy, Raw.Arg2),
getValue(Type::BoolTy , Raw.Arg3));
return false;
}
} else if (Raw.Opcode == Instruction::Switch) {
SwitchInst *I =
new SwitchInst(getValue(Raw.Ty, Raw.Arg1),
(BasicBlock*)getValue(Type::LabelTy, Raw.Arg2));
Res = I;
if (Raw.NumOperands < 3) return false; // No destinations? Wierd.
if (Raw.NumOperands == 3 || Raw.VarArgs->size() & 1) {
cerr << "Switch statement with odd number of arguments!\n";
delete I;
return true;
}
vector<unsigned> &args = *Raw.VarArgs;
for (unsigned i = 0; i < args.size(); i += 2)
I->dest_push_back((ConstPoolVal*)getValue(Raw.Ty, args[i]),
(BasicBlock*)getValue(Type::LabelTy, args[i+1]));
delete Raw.VarArgs;
return false;
} else if (Raw.Opcode == Instruction::Call) {
Method *M = (Method*)getValue(Raw.Ty, Raw.Arg1);
if (M == 0) return true;
const MethodType::ParamTypes &PL = M->getMethodType()->getParamTypes();
MethodType::ParamTypes::const_iterator It = PL.begin();
vector<Value *> Params;
switch (Raw.NumOperands) {
case 0: cerr << "Invalid call instruction encountered!\n";
return true;
case 1: break;
case 2: Params.push_back(getValue(*It++, Raw.Arg2)); break;
case 3: Params.push_back(getValue(*It++, Raw.Arg2));
if (It == PL.end()) return true;
Params.push_back(getValue(*It++, Raw.Arg3)); break;
default:
Params.push_back(getValue(*It++, Raw.Arg2));
{
vector<unsigned> &args = *Raw.VarArgs;
for (unsigned i = 0; i < args.size(); i++) {
if (It == PL.end()) return true;
Params.push_back(getValue(*It++, args[i]));
}
}
delete Raw.VarArgs;
}
if (It != PL.end()) return true;
Res = new CallInst(M, Params);
return false;
} else if (Raw.Opcode == Instruction::Malloc) {
if (Raw.NumOperands > 2) return true;
Value *Sz = (Raw.NumOperands == 2) ? getValue(Type::UIntTy, Raw.Arg2) : 0;
Res = new MallocInst((ConstPoolType*)getValue(Type::TypeTy, Raw.Arg1), Sz);
return false;
} else if (Raw.Opcode == Instruction::Alloca) {
if (Raw.NumOperands > 2) return true;
Value *Sz = (Raw.NumOperands == 2) ? getValue(Type::UIntTy, Raw.Arg2) : 0;
Res = new AllocaInst((ConstPoolType*)getValue(Type::TypeTy, Raw.Arg1), Sz);
return false;
} else if (Raw.Opcode == Instruction::Free) {
Value *Val = getValue(Raw.Ty, Raw.Arg1);
if (!Val->getType()->isPointerType()) return true;
Res = new FreeInst(Val);
return false;
}
cerr << "Unrecognized instruction! " << Raw.Opcode << endl;
return true;
}
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