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//===-- PPC32CodeEmitter.cpp - JIT Code Emitter for PowerPC32 -----*- C++ -*-=//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the PowerPC 32-bit CodeEmitter and associated machinery to
// JIT-compile bytecode to native PowerPC.
//
//===----------------------------------------------------------------------===//
#include "PPC32TargetMachine.h"
#include "PPC32Relocations.h"
#include "PowerPC.h"
#include "llvm/Module.h"
#include "llvm/CodeGen/MachineCodeEmitter.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/Support/Debug.h"
using namespace llvm;
namespace {
class PPC32CodeEmitter : public MachineFunctionPass {
TargetMachine &TM;
MachineCodeEmitter &MCE;
/// MovePCtoLROffset - When/if we see a MovePCtoLR instruction, we record
/// its address in the function into this pointer.
void *MovePCtoLROffset;
// Tracks which instruction references which BasicBlock
std::vector<std::pair<MachineBasicBlock*, unsigned*> > BBRefs;
// Tracks where each BasicBlock starts
std::map<MachineBasicBlock*, long> BBLocations;
/// getMachineOpValue - evaluates the MachineOperand of a given MachineInstr
///
int getMachineOpValue(MachineInstr &MI, MachineOperand &MO);
public:
PPC32CodeEmitter(TargetMachine &T, MachineCodeEmitter &M)
: TM(T), MCE(M) {}
const char *getPassName() const { return "PowerPC Machine Code Emitter"; }
/// runOnMachineFunction - emits the given MachineFunction to memory
///
bool runOnMachineFunction(MachineFunction &MF);
/// emitBasicBlock - emits the given MachineBasicBlock to memory
///
void emitBasicBlock(MachineBasicBlock &MBB);
/// emitWord - write a 32-bit word to memory at the current PC
///
void emitWord(unsigned w) { MCE.emitWord(w); }
/// getValueBit - return the particular bit of Val
///
unsigned getValueBit(int64_t Val, unsigned bit) { return (Val >> bit) & 1; }
/// getBinaryCodeForInstr - This function, generated by the
/// CodeEmitterGenerator using TableGen, produces the binary encoding for
/// machine instructions.
///
unsigned getBinaryCodeForInstr(MachineInstr &MI);
};
}
/// addPassesToEmitMachineCode - Add passes to the specified pass manager to get
/// machine code emitted. This uses a MachineCodeEmitter object to handle
/// actually outputting the machine code and resolving things like the address
/// of functions. This method should returns true if machine code emission is
/// not supported.
///
bool PPC32TargetMachine::addPassesToEmitMachineCode(FunctionPassManager &PM,
MachineCodeEmitter &MCE) {
// Machine code emitter pass for PowerPC
PM.add(new PPC32CodeEmitter(*this, MCE));
// Delete machine code for this function after emitting it
PM.add(createMachineCodeDeleter());
return false;
}
bool PPC32CodeEmitter::runOnMachineFunction(MachineFunction &MF) {
MovePCtoLROffset = 0;
MCE.startFunction(MF);
MCE.emitConstantPool(MF.getConstantPool());
for (MachineFunction::iterator BB = MF.begin(), E = MF.end(); BB != E; ++BB)
emitBasicBlock(*BB);
MCE.finishFunction(MF);
// Resolve branches to BasicBlocks for the entire function
for (unsigned i = 0, e = BBRefs.size(); i != e; ++i) {
intptr_t Location = BBLocations[BBRefs[i].first];
unsigned *Ref = BBRefs[i].second;
DEBUG(std::cerr << "Fixup @ " << (void*)Ref << " to " << (void*)Location
<< "\n");
unsigned Instr = *Ref;
intptr_t BranchTargetDisp = (Location - (intptr_t)Ref) >> 2;
switch (Instr >> 26) {
default: assert(0 && "Unknown branch user!");
case 18: // This is B or BL
*Ref |= (BranchTargetDisp & ((1 << 24)-1)) << 2;
break;
case 16: // This is BLT,BLE,BEQ,BGE,BGT,BNE, or other bcx instruction
*Ref |= (BranchTargetDisp & ((1 << 14)-1)) << 2;
break;
}
}
BBRefs.clear();
BBLocations.clear();
return false;
}
void PPC32CodeEmitter::emitBasicBlock(MachineBasicBlock &MBB) {
BBLocations[&MBB] = MCE.getCurrentPCValue();
for (MachineBasicBlock::iterator I = MBB.begin(), E = MBB.end(); I != E; ++I){
MachineInstr &MI = *I;
unsigned Opcode = MI.getOpcode();
switch (MI.getOpcode()) {
default:
emitWord(getBinaryCodeForInstr(*I));
break;
case PPC::IMPLICIT_DEF:
break; // pseudo opcode, no side effects
case PPC::MovePCtoLR:
assert(MovePCtoLROffset == 0 &&
"Multiple MovePCtoLR instructions in the function?");
MovePCtoLROffset = (void*)(intptr_t)MCE.getCurrentPCValue();
emitWord(0x48000005); // bl 1
break;
}
}
}
static unsigned enumRegToMachineReg(unsigned enumReg) {
switch (enumReg) {
case PPC::R0 : case PPC::F0 : case PPC::CR0: return 0;
case PPC::R1 : case PPC::F1 : case PPC::CR1: return 1;
case PPC::R2 : case PPC::F2 : case PPC::CR2: return 2;
case PPC::R3 : case PPC::F3 : case PPC::CR3: return 3;
case PPC::R4 : case PPC::F4 : case PPC::CR4: return 4;
case PPC::R5 : case PPC::F5 : case PPC::CR5: return 5;
case PPC::R6 : case PPC::F6 : case PPC::CR6: return 6;
case PPC::R7 : case PPC::F7 : case PPC::CR7: return 7;
case PPC::R8 : case PPC::F8 : return 8;
case PPC::R9 : case PPC::F9 : return 9;
case PPC::R10: case PPC::F10: return 10;
case PPC::R11: case PPC::F11: return 11;
case PPC::R12: case PPC::F12: return 12;
case PPC::R13: case PPC::F13: return 13;
case PPC::R14: case PPC::F14: return 14;
case PPC::R15: case PPC::F15: return 15;
case PPC::R16: case PPC::F16: return 16;
case PPC::R17: case PPC::F17: return 17;
case PPC::R18: case PPC::F18: return 18;
case PPC::R19: case PPC::F19: return 19;
case PPC::R20: case PPC::F20: return 20;
case PPC::R21: case PPC::F21: return 21;
case PPC::R22: case PPC::F22: return 22;
case PPC::R23: case PPC::F23: return 23;
case PPC::R24: case PPC::F24: return 24;
case PPC::R25: case PPC::F25: return 25;
case PPC::R26: case PPC::F26: return 26;
case PPC::R27: case PPC::F27: return 27;
case PPC::R28: case PPC::F28: return 28;
case PPC::R29: case PPC::F29: return 29;
case PPC::R30: case PPC::F30: return 30;
case PPC::R31: case PPC::F31: return 31;
default:
std::cerr << "Unhandled reg in enumRegToRealReg!\n";
abort();
}
}
int PPC32CodeEmitter::getMachineOpValue(MachineInstr &MI, MachineOperand &MO) {
int rv = 0; // Return value; defaults to 0 for unhandled cases
// or things that get fixed up later by the JIT.
if (MO.isRegister()) {
rv = enumRegToMachineReg(MO.getReg());
} else if (MO.isImmediate()) {
rv = MO.getImmedValue();
} else if (MO.isGlobalAddress() || MO.isExternalSymbol()) {
bool isExternal = MO.isExternalSymbol() ||
MO.getGlobal()->hasWeakLinkage() ||
MO.getGlobal()->isExternal();
unsigned Reloc = 0;
int Offset = 0;
if (MI.getOpcode() == PPC::CALLpcrel)
Reloc = PPC::reloc_pcrel_bx;
else {
assert(MovePCtoLROffset && "MovePCtoLR not seen yet?");
Offset = -((intptr_t)MovePCtoLROffset+4);
if (MI.getOpcode() == PPC::LOADHiAddr) {
if (isExternal)
Reloc = PPC::reloc_absolute_ptr_high; // Pointer to stub
else
Reloc = PPC::reloc_absolute_high; // Pointer to symbol
} else if (MI.getOpcode() == PPC::LA) {
assert(!isExternal && "Something in the ISEL changed\n");
Reloc = PPC::reloc_absolute_low;
} else if (MI.getOpcode() == PPC::LWZ) {
Reloc = PPC::reloc_absolute_ptr_low;
assert(isExternal && "Something in the ISEL changed\n");
} else {
// These don't show up for global value references AFAIK, only for
// constant pool refs: PPC::LFS, PPC::LFD
assert(0 && "Unknown instruction for relocation!");
}
}
if (MO.isGlobalAddress())
MCE.addRelocation(MachineRelocation(MCE.getCurrentPCOffset(),
Reloc, MO.getGlobal(), Offset));
else
MCE.addRelocation(MachineRelocation(MCE.getCurrentPCOffset(),
Reloc, MO.getSymbolName(), Offset));
} else if (MO.isMachineBasicBlock()) {
unsigned* CurrPC = (unsigned*)(intptr_t)MCE.getCurrentPCValue();
BBRefs.push_back(std::make_pair(MO.getMachineBasicBlock(), CurrPC));
} else if (MO.isConstantPoolIndex()) {
unsigned index = MO.getConstantPoolIndex();
assert(MovePCtoLROffset && "MovePCtoLR not seen yet?");
rv = MCE.getConstantPoolEntryAddress(index) - (intptr_t)MovePCtoLROffset-4;
unsigned Opcode = MI.getOpcode();
if (Opcode == PPC::LOADHiAddr) {
// LoadHiAddr wants hi16(addr - &MovePCtoLR)
if ((short)rv < 0) rv += 1 << 16;
rv >>= 16;
} else if (Opcode == PPC::LWZ || Opcode == PPC::LA ||
Opcode == PPC::LFS || Opcode == PPC::LFD) {
// These load opcodes want lo16(addr - &MovePCtoLR)
rv &= 0xffff;
} else {
assert(0 && "Unknown constant pool using instruction!");
}
} else {
std::cerr << "ERROR: Unknown type of MachineOperand: " << MO << "\n";
abort();
}
return rv;
}
#include "PPC32GenCodeEmitter.inc"
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