llvm/lib/Target/PowerPC/PPCCodeEmitter.cpp
Ulrich Weigand 33efedc048 [PowerPC] Use mtocrf when available
Just as with mfocrf, it is also preferable to use mtocrf instead of
mtcrf when only a single CR register is to be written.

Current code however always emits mtcrf.  This probably does not matter
when using an external assembler, since the GNU assembler will in fact
automatically replace mtcrf with mtocrf when possible.  It does create
inefficient code with the integrated assembler, however.

To fix this, this patch adds MTOCRF/MTOCRF8 instruction patterns and
uses those instead of MTCRF/MTCRF8 everything.  Just as done in the
MFOCRF patch committed as 185556, these patterns will be converted
back to MTCRF if MTOCRF is not available on the machine.

As a side effect, this allows to modify the MTCRF pattern to accept
the full range of mask operands for the benefit of the asm parser.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185561 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-03 17:59:07 +00:00

291 lines
11 KiB
C++

//===-- PPCCodeEmitter.cpp - JIT Code Emitter for PowerPC -----------------===//
//
// The LLVM Compiler Infrastructure
//
// This file 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 bitcode to native PowerPC.
//
//===----------------------------------------------------------------------===//
#include "PPC.h"
#include "PPCRelocations.h"
#include "PPCTargetMachine.h"
#include "llvm/CodeGen/JITCodeEmitter.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/IR/Module.h"
#include "llvm/PassManager.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetOptions.h"
using namespace llvm;
namespace {
class PPCCodeEmitter : public MachineFunctionPass {
TargetMachine &TM;
JITCodeEmitter &MCE;
MachineModuleInfo *MMI;
void getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<MachineModuleInfo>();
MachineFunctionPass::getAnalysisUsage(AU);
}
static char ID;
/// MovePCtoLROffset - When/if we see a MovePCtoLR instruction, we record
/// its address in the function into this pointer.
void *MovePCtoLROffset;
public:
PPCCodeEmitter(TargetMachine &tm, JITCodeEmitter &mce)
: MachineFunctionPass(ID), TM(tm), MCE(mce) {}
/// getBinaryCodeForInstr - This function, generated by the
/// CodeEmitterGenerator using TableGen, produces the binary encoding for
/// machine instructions.
uint64_t getBinaryCodeForInstr(const MachineInstr &MI) const;
MachineRelocation GetRelocation(const MachineOperand &MO,
unsigned RelocID) const;
/// getMachineOpValue - evaluates the MachineOperand of a given MachineInstr
unsigned getMachineOpValue(const MachineInstr &MI,
const MachineOperand &MO) const;
unsigned get_crbitm_encoding(const MachineInstr &MI, unsigned OpNo) const;
unsigned getDirectBrEncoding(const MachineInstr &MI, unsigned OpNo) const;
unsigned getCondBrEncoding(const MachineInstr &MI, unsigned OpNo) const;
unsigned getAbsDirectBrEncoding(const MachineInstr &MI,
unsigned OpNo) const;
unsigned getAbsCondBrEncoding(const MachineInstr &MI, unsigned OpNo) const;
unsigned getImm16Encoding(const MachineInstr &MI, unsigned OpNo) const;
unsigned getMemRIEncoding(const MachineInstr &MI, unsigned OpNo) const;
unsigned getMemRIXEncoding(const MachineInstr &MI, unsigned OpNo) const;
unsigned getTLSRegEncoding(const MachineInstr &MI, unsigned OpNo) const;
unsigned getTLSCallEncoding(const MachineInstr &MI, unsigned OpNo) const;
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);
};
}
char PPCCodeEmitter::ID = 0;
/// createPPCCodeEmitterPass - Return a pass that emits the collected PPC code
/// to the specified MCE object.
FunctionPass *llvm::createPPCJITCodeEmitterPass(PPCTargetMachine &TM,
JITCodeEmitter &JCE) {
return new PPCCodeEmitter(TM, JCE);
}
bool PPCCodeEmitter::runOnMachineFunction(MachineFunction &MF) {
assert((MF.getTarget().getRelocationModel() != Reloc::Default ||
MF.getTarget().getRelocationModel() != Reloc::Static) &&
"JIT relocation model must be set to static or default!");
MMI = &getAnalysis<MachineModuleInfo>();
MCE.setModuleInfo(MMI);
do {
MovePCtoLROffset = 0;
MCE.startFunction(MF);
for (MachineFunction::iterator BB = MF.begin(), E = MF.end(); BB != E; ++BB)
emitBasicBlock(*BB);
} while (MCE.finishFunction(MF));
return false;
}
void PPCCodeEmitter::emitBasicBlock(MachineBasicBlock &MBB) {
MCE.StartMachineBasicBlock(&MBB);
for (MachineBasicBlock::iterator I = MBB.begin(), E = MBB.end(); I != E; ++I){
const MachineInstr &MI = *I;
MCE.processDebugLoc(MI.getDebugLoc(), true);
switch (MI.getOpcode()) {
default:
MCE.emitWordBE(getBinaryCodeForInstr(MI));
break;
case TargetOpcode::PROLOG_LABEL:
case TargetOpcode::EH_LABEL:
MCE.emitLabel(MI.getOperand(0).getMCSymbol());
break;
case TargetOpcode::IMPLICIT_DEF:
case TargetOpcode::KILL:
break; // pseudo opcode, no side effects
case PPC::MovePCtoLR:
case PPC::MovePCtoLR8:
assert(TM.getRelocationModel() == Reloc::PIC_);
MovePCtoLROffset = (void*)MCE.getCurrentPCValue();
MCE.emitWordBE(0x48000005); // bl 1
break;
}
MCE.processDebugLoc(MI.getDebugLoc(), false);
}
}
unsigned PPCCodeEmitter::get_crbitm_encoding(const MachineInstr &MI,
unsigned OpNo) const {
const MachineOperand &MO = MI.getOperand(OpNo);
assert((MI.getOpcode() == PPC::MTOCRF || MI.getOpcode() == PPC::MTOCRF8 ||
MI.getOpcode() == PPC::MFOCRF || MI.getOpcode() == PPC::MFOCRF8) &&
(MO.getReg() >= PPC::CR0 && MO.getReg() <= PPC::CR7));
return 0x80 >> TM.getRegisterInfo()->getEncodingValue(MO.getReg());
}
MachineRelocation PPCCodeEmitter::GetRelocation(const MachineOperand &MO,
unsigned RelocID) const {
// If in PIC mode, we need to encode the negated address of the
// 'movepctolr' into the unrelocated field. After relocation, we'll have
// &gv-&movepctolr-4 in the imm field. Once &movepctolr is added to the imm
// field, we get &gv. This doesn't happen for branch relocations, which are
// always implicitly pc relative.
intptr_t Cst = 0;
if (TM.getRelocationModel() == Reloc::PIC_) {
assert(MovePCtoLROffset && "MovePCtoLR not seen yet?");
Cst = -(intptr_t)MovePCtoLROffset - 4;
}
if (MO.isGlobal())
return MachineRelocation::getGV(MCE.getCurrentPCOffset(), RelocID,
const_cast<GlobalValue *>(MO.getGlobal()),
Cst, isa<Function>(MO.getGlobal()));
if (MO.isSymbol())
return MachineRelocation::getExtSym(MCE.getCurrentPCOffset(),
RelocID, MO.getSymbolName(), Cst);
if (MO.isCPI())
return MachineRelocation::getConstPool(MCE.getCurrentPCOffset(),
RelocID, MO.getIndex(), Cst);
if (MO.isMBB())
return MachineRelocation::getBB(MCE.getCurrentPCOffset(),
RelocID, MO.getMBB());
assert(MO.isJTI());
return MachineRelocation::getJumpTable(MCE.getCurrentPCOffset(),
RelocID, MO.getIndex(), Cst);
}
unsigned PPCCodeEmitter::getDirectBrEncoding(const MachineInstr &MI,
unsigned OpNo) const {
const MachineOperand &MO = MI.getOperand(OpNo);
if (MO.isReg() || MO.isImm()) return getMachineOpValue(MI, MO);
MCE.addRelocation(GetRelocation(MO, PPC::reloc_pcrel_bx));
return 0;
}
unsigned PPCCodeEmitter::getCondBrEncoding(const MachineInstr &MI,
unsigned OpNo) const {
const MachineOperand &MO = MI.getOperand(OpNo);
MCE.addRelocation(GetRelocation(MO, PPC::reloc_pcrel_bcx));
return 0;
}
unsigned PPCCodeEmitter::getAbsDirectBrEncoding(const MachineInstr &MI,
unsigned OpNo) const {
const MachineOperand &MO = MI.getOperand(OpNo);
if (MO.isReg() || MO.isImm()) return getMachineOpValue(MI, MO);
llvm_unreachable("Absolute branch relocations unsupported on the old JIT.");
}
unsigned PPCCodeEmitter::getAbsCondBrEncoding(const MachineInstr &MI,
unsigned OpNo) const {
llvm_unreachable("Absolute branch relocations unsupported on the old JIT.");
}
unsigned PPCCodeEmitter::getImm16Encoding(const MachineInstr &MI,
unsigned OpNo) const {
const MachineOperand &MO = MI.getOperand(OpNo);
if (MO.isReg() || MO.isImm()) return getMachineOpValue(MI, MO);
unsigned RelocID;
switch (MO.getTargetFlags() & PPCII::MO_ACCESS_MASK) {
default: llvm_unreachable("Unsupported target operand flags!");
case PPCII::MO_LO: RelocID = PPC::reloc_absolute_low; break;
case PPCII::MO_HA: RelocID = PPC::reloc_absolute_high; break;
}
MCE.addRelocation(GetRelocation(MO, RelocID));
return 0;
}
unsigned PPCCodeEmitter::getMemRIEncoding(const MachineInstr &MI,
unsigned OpNo) const {
// Encode (imm, reg) as a memri, which has the low 16-bits as the
// displacement and the next 5 bits as the register #.
assert(MI.getOperand(OpNo+1).isReg());
unsigned RegBits = getMachineOpValue(MI, MI.getOperand(OpNo+1)) << 16;
const MachineOperand &MO = MI.getOperand(OpNo);
if (MO.isImm())
return (getMachineOpValue(MI, MO) & 0xFFFF) | RegBits;
// Add a fixup for the displacement field.
MCE.addRelocation(GetRelocation(MO, PPC::reloc_absolute_low));
return RegBits;
}
unsigned PPCCodeEmitter::getMemRIXEncoding(const MachineInstr &MI,
unsigned OpNo) const {
// Encode (imm, reg) as a memrix, which has the low 14-bits as the
// displacement and the next 5 bits as the register #.
assert(MI.getOperand(OpNo+1).isReg());
unsigned RegBits = getMachineOpValue(MI, MI.getOperand(OpNo+1)) << 14;
const MachineOperand &MO = MI.getOperand(OpNo);
if (MO.isImm())
return ((getMachineOpValue(MI, MO) >> 2) & 0x3FFF) | RegBits;
MCE.addRelocation(GetRelocation(MO, PPC::reloc_absolute_low_ix));
return RegBits;
}
unsigned PPCCodeEmitter::getTLSRegEncoding(const MachineInstr &MI,
unsigned OpNo) const {
llvm_unreachable("TLS not supported on the old JIT.");
return 0;
}
unsigned PPCCodeEmitter::getTLSCallEncoding(const MachineInstr &MI,
unsigned OpNo) const {
llvm_unreachable("TLS not supported on the old JIT.");
return 0;
}
unsigned PPCCodeEmitter::getMachineOpValue(const MachineInstr &MI,
const MachineOperand &MO) const {
if (MO.isReg()) {
// MTOCRF/MFOCRF should go through get_crbitm_encoding for the CR operand.
// The GPR operand should come through here though.
assert((MI.getOpcode() != PPC::MTOCRF && MI.getOpcode() != PPC::MTOCRF8 &&
MI.getOpcode() != PPC::MFOCRF && MI.getOpcode() != PPC::MFOCRF8) ||
MO.getReg() < PPC::CR0 || MO.getReg() > PPC::CR7);
return TM.getRegisterInfo()->getEncodingValue(MO.getReg());
}
assert(MO.isImm() &&
"Relocation required in an instruction that we cannot encode!");
return MO.getImm();
}
#include "PPCGenCodeEmitter.inc"