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https://github.com/c64scene-ar/llvm-6502.git
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returning error codes. Because they don't return an error code, they can return the value read, which simplifies the code and makes the reader more efficient (yaay!). Also eliminate the special case code for little endian machines. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@10871 91177308-0d34-0410-b5e6-96231b3b80d8
394 lines
13 KiB
C++
394 lines
13 KiB
C++
//===- ReadInst.cpp - Code to read an instruction from bytecode -----------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file was developed by the LLVM research group and is distributed under
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// the University of Illinois Open Source License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines the mechanism to read an instruction from a bytecode
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// stream.
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//
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// Note that this library should be as fast as possible, reentrant, and
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// threadsafe!!
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//
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//===----------------------------------------------------------------------===//
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#include "ReaderInternals.h"
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#include "llvm/iTerminators.h"
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#include "llvm/iMemory.h"
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#include "llvm/iPHINode.h"
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#include "llvm/iOther.h"
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#include "llvm/Module.h"
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using namespace llvm;
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namespace {
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struct RawInst { // The raw fields out of the bytecode stream...
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unsigned NumOperands;
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unsigned Opcode;
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unsigned Type;
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RawInst(const unsigned char *&Buf, const unsigned char *EndBuf,
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std::vector<unsigned> &Args);
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};
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}
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RawInst::RawInst(const unsigned char *&Buf, const unsigned char *EndBuf,
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std::vector<unsigned> &Args) {
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unsigned Op = read(Buf, EndBuf);
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// bits Instruction format: Common to all formats
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// --------------------------
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// 01-00: Opcode type, fixed to 1.
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// 07-02: Opcode
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Opcode = (Op >> 2) & 63;
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Args.resize((Op >> 0) & 03);
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switch (Args.size()) {
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case 1:
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// bits Instruction format:
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// --------------------------
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// 19-08: Resulting type plane
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// 31-20: Operand #1 (if set to (2^12-1), then zero operands)
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//
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Type = (Op >> 8) & 4095;
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Args[0] = (Op >> 20) & 4095;
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if (Args[0] == 4095) // Handle special encoding for 0 operands...
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Args.resize(0);
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break;
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case 2:
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// bits Instruction format:
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// --------------------------
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// 15-08: Resulting type plane
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// 23-16: Operand #1
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// 31-24: Operand #2
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//
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Type = (Op >> 8) & 255;
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Args[0] = (Op >> 16) & 255;
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Args[1] = (Op >> 24) & 255;
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break;
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case 3:
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// bits Instruction format:
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// --------------------------
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// 13-08: Resulting type plane
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// 19-14: Operand #1
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// 25-20: Operand #2
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// 31-26: Operand #3
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//
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Type = (Op >> 8) & 63;
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Args[0] = (Op >> 14) & 63;
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Args[1] = (Op >> 20) & 63;
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Args[2] = (Op >> 26) & 63;
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break;
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case 0:
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Buf -= 4; // Hrm, try this again...
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Opcode = read_vbr_uint(Buf, EndBuf);
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Opcode >>= 2;
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Type = read_vbr_uint(Buf, EndBuf);
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unsigned NumOperands = read_vbr_uint(Buf, EndBuf);
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Args.resize(NumOperands);
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if (NumOperands == 0)
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throw std::string("Zero-argument instruction found; this is invalid.");
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for (unsigned i = 0; i != NumOperands; ++i)
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Args[i] = read_vbr_uint(Buf, EndBuf);
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align32(Buf, EndBuf);
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break;
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}
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}
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void BytecodeParser::ParseInstruction(const unsigned char *&Buf,
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const unsigned char *EndBuf,
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std::vector<unsigned> &Args,
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BasicBlock *BB) {
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Args.clear();
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RawInst RI(Buf, EndBuf, Args);
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const Type *InstTy = getType(RI.Type);
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Instruction *Result = 0;
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if (RI.Opcode >= Instruction::BinaryOpsBegin &&
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RI.Opcode < Instruction::BinaryOpsEnd && Args.size() == 2)
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Result = BinaryOperator::create((Instruction::BinaryOps)RI.Opcode,
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getValue(RI.Type, Args[0]),
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getValue(RI.Type, Args[1]));
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switch (RI.Opcode) {
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default:
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if (Result == 0) throw std::string("Illegal instruction read!");
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break;
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case Instruction::VAArg:
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Result = new VAArgInst(getValue(RI.Type, Args[0]), getType(Args[1]));
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break;
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case Instruction::VANext:
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if (!hasOldStyleVarargs) {
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Result = new VANextInst(getValue(RI.Type, Args[0]), getType(Args[1]));
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} else {
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// In the old-style varargs scheme, this was the "va_arg" instruction.
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// Emit emulation code now.
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if (!usesOldStyleVarargs) {
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usesOldStyleVarargs = true;
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std::cerr << "WARNING: this bytecode file uses obsolete features. "
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<< "Disassemble and assemble to update it.\n";
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}
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Value *VAListPtr = getValue(RI.Type, Args[0]);
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const Type *ArgTy = getType(Args[1]);
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// First, load the valist...
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Instruction *CurVAList = new LoadInst(VAListPtr, "");
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BB->getInstList().push_back(CurVAList);
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// Construct the vaarg
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Result = new VAArgInst(CurVAList, ArgTy);
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// Now we must advance the pointer and update it in memory.
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Instruction *TheVANext = new VANextInst(CurVAList, ArgTy);
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BB->getInstList().push_back(TheVANext);
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BB->getInstList().push_back(new StoreInst(TheVANext, VAListPtr));
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}
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break;
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case Instruction::Cast:
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Result = new CastInst(getValue(RI.Type, Args[0]), getType(Args[1]));
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break;
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case Instruction::PHI: {
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if (Args.size() == 0 || (Args.size() & 1))
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throw std::string("Invalid phi node encountered!\n");
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PHINode *PN = new PHINode(InstTy);
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PN->op_reserve(Args.size());
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for (unsigned i = 0, e = Args.size(); i != e; i += 2)
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PN->addIncoming(getValue(RI.Type, Args[i]), getBasicBlock(Args[i+1]));
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Result = PN;
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break;
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}
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case Instruction::Shl:
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case Instruction::Shr:
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Result = new ShiftInst((Instruction::OtherOps)RI.Opcode,
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getValue(RI.Type, Args[0]),
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getValue(Type::UByteTyID, Args[1]));
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break;
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case Instruction::Ret:
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if (Args.size() == 0)
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Result = new ReturnInst();
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else if (Args.size() == 1)
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Result = new ReturnInst(getValue(RI.Type, Args[0]));
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else
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throw std::string("Unrecognized instruction!");
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break;
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case Instruction::Br:
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if (Args.size() == 1)
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Result = new BranchInst(getBasicBlock(Args[0]));
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else if (Args.size() == 3)
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Result = new BranchInst(getBasicBlock(Args[0]), getBasicBlock(Args[1]),
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getValue(Type::BoolTyID , Args[2]));
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else
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throw std::string("Invalid number of operands for a 'br' instruction!");
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break;
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case Instruction::Switch: {
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if (Args.size() & 1)
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throw std::string("Switch statement with odd number of arguments!");
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SwitchInst *I = new SwitchInst(getValue(RI.Type, Args[0]),
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getBasicBlock(Args[1]));
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for (unsigned i = 2, e = Args.size(); i != e; i += 2)
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I->addCase(cast<Constant>(getValue(RI.Type, Args[i])),
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getBasicBlock(Args[i+1]));
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Result = I;
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break;
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}
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case Instruction::Call: {
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if (Args.size() == 0)
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throw std::string("Invalid call instruction encountered!");
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Value *F = getValue(RI.Type, Args[0]);
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// Check to make sure we have a pointer to function type
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const PointerType *PTy = dyn_cast<PointerType>(F->getType());
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if (PTy == 0) throw std::string("Call to non function pointer value!");
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const FunctionType *FTy = dyn_cast<FunctionType>(PTy->getElementType());
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if (FTy == 0) throw std::string("Call to non function pointer value!");
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std::vector<Value *> Params;
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const FunctionType::ParamTypes &PL = FTy->getParamTypes();
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if (!FTy->isVarArg()) {
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FunctionType::ParamTypes::const_iterator It = PL.begin();
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for (unsigned i = 1, e = Args.size(); i != e; ++i) {
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if (It == PL.end()) throw std::string("Invalid call instruction!");
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Params.push_back(getValue(getTypeSlot(*It++), Args[i]));
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}
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if (It != PL.end()) throw std::string("Invalid call instruction!");
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} else {
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Args.erase(Args.begin(), Args.begin()+1+hasVarArgCallPadding);
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unsigned FirstVariableOperand;
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if (!hasVarArgCallPadding) {
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if (Args.size() < FTy->getNumParams())
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throw std::string("Call instruction missing operands!");
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// Read all of the fixed arguments
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for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
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Params.push_back(getValue(getTypeSlot(FTy->getParamType(i)),Args[i]));
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FirstVariableOperand = FTy->getNumParams();
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} else {
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FirstVariableOperand = 0;
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}
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if ((Args.size()-FirstVariableOperand) & 1) // Must be pairs of type/value
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throw std::string("Invalid call instruction!");
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for (unsigned i = FirstVariableOperand, e = Args.size(); i != e; i += 2)
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Params.push_back(getValue(Args[i], Args[i+1]));
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}
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Result = new CallInst(F, Params);
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break;
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}
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case Instruction::Invoke: {
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if (Args.size() < 3) throw std::string("Invalid invoke instruction!");
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Value *F = getValue(RI.Type, Args[0]);
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// Check to make sure we have a pointer to function type
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const PointerType *PTy = dyn_cast<PointerType>(F->getType());
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if (PTy == 0) throw std::string("Invoke to non function pointer value!");
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const FunctionType *FTy = dyn_cast<FunctionType>(PTy->getElementType());
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if (FTy == 0) throw std::string("Invoke to non function pointer value!");
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std::vector<Value *> Params;
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BasicBlock *Normal, *Except;
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const FunctionType::ParamTypes &PL = FTy->getParamTypes();
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if (!FTy->isVarArg()) {
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Normal = getBasicBlock(Args[1]);
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Except = getBasicBlock(Args[2]);
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FunctionType::ParamTypes::const_iterator It = PL.begin();
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for (unsigned i = 3, e = Args.size(); i != e; ++i) {
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if (It == PL.end()) throw std::string("Invalid invoke instruction!");
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Params.push_back(getValue(getTypeSlot(*It++), Args[i]));
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}
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if (It != PL.end()) throw std::string("Invalid invoke instruction!");
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} else {
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Args.erase(Args.begin(), Args.begin()+1+hasVarArgCallPadding);
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unsigned FirstVariableArgument;
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if (!hasVarArgCallPadding) {
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Normal = getBasicBlock(Args[0]);
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Except = getBasicBlock(Args[1]);
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FirstVariableArgument = FTy->getNumParams()+2;
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for (unsigned i = 2; i != FirstVariableArgument; ++i)
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Params.push_back(getValue(getTypeSlot(FTy->getParamType(i-2)),
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Args[i]));
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} else {
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if (Args.size() < 4) throw std::string("Invalid invoke instruction!");
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if (Args[0] != Type::LabelTyID || Args[2] != Type::LabelTyID)
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throw std::string("Invalid invoke instruction!");
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Normal = getBasicBlock(Args[1]);
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Except = getBasicBlock(Args[3]);
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FirstVariableArgument = 4;
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}
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if (Args.size()-FirstVariableArgument & 1) // Must be pairs of type/value
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throw std::string("Invalid invoke instruction!");
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for (unsigned i = FirstVariableArgument; i < Args.size(); i += 2)
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Params.push_back(getValue(Args[i], Args[i+1]));
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}
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Result = new InvokeInst(F, Normal, Except, Params);
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break;
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}
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case Instruction::Malloc:
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if (Args.size() > 2) throw std::string("Invalid malloc instruction!");
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if (!isa<PointerType>(InstTy))
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throw std::string("Invalid malloc instruction!");
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Result = new MallocInst(cast<PointerType>(InstTy)->getElementType(),
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Args.size() ? getValue(Type::UIntTyID,
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Args[0]) : 0);
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break;
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case Instruction::Alloca:
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if (Args.size() > 2) throw std::string("Invalid alloca instruction!");
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if (!isa<PointerType>(InstTy))
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throw std::string("Invalid alloca instruction!");
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Result = new AllocaInst(cast<PointerType>(InstTy)->getElementType(),
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Args.size() ? getValue(Type::UIntTyID, Args[0]) :0);
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break;
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case Instruction::Free:
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if (!isa<PointerType>(InstTy))
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throw std::string("Invalid free instruction!");
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Result = new FreeInst(getValue(RI.Type, Args[0]));
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break;
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case Instruction::GetElementPtr: {
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if (Args.size() == 0 || !isa<PointerType>(InstTy))
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throw std::string("Invalid getelementptr instruction!");
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std::vector<Value*> Idx;
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const Type *NextTy = InstTy;
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for (unsigned i = 1, e = Args.size(); i != e; ++i) {
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const CompositeType *TopTy = dyn_cast_or_null<CompositeType>(NextTy);
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if (!TopTy) throw std::string("Invalid getelementptr instruction!");
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// FIXME: when PR82 is resolved.
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unsigned IdxTy = isa<StructType>(TopTy) ? Type::UByteTyID :Type::LongTyID;
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Idx.push_back(getValue(IdxTy, Args[i]));
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NextTy = GetElementPtrInst::getIndexedType(InstTy, Idx, true);
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}
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Result = new GetElementPtrInst(getValue(RI.Type, Args[0]), Idx);
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break;
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}
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case 62: // volatile load
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case Instruction::Load:
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if (Args.size() != 1 || !isa<PointerType>(InstTy))
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throw std::string("Invalid load instruction!");
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Result = new LoadInst(getValue(RI.Type, Args[0]), "", RI.Opcode == 62);
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break;
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case 63: // volatile store
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case Instruction::Store: {
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if (!isa<PointerType>(InstTy) || Args.size() != 2)
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throw std::string("Invalid store instruction!");
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Value *Ptr = getValue(RI.Type, Args[1]);
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const Type *ValTy = cast<PointerType>(Ptr->getType())->getElementType();
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Result = new StoreInst(getValue(getTypeSlot(ValTy), Args[0]), Ptr,
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RI.Opcode == 63);
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break;
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}
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case Instruction::Unwind:
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if (Args.size() != 0) throw std::string("Invalid unwind instruction!");
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Result = new UnwindInst();
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break;
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} // end switch(RI.Opcode)
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unsigned TypeSlot;
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if (Result->getType() == InstTy)
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TypeSlot = RI.Type;
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else
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TypeSlot = getTypeSlot(Result->getType());
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insertValue(Result, TypeSlot, Values);
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BB->getInstList().push_back(Result);
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BCR_TRACE(4, *Result);
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}
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