llvm-for-llvmta/lib/Target/PowerPC/MCTargetDesc/PPCMCCodeEmitter.cpp

478 lines
20 KiB
C++

//===-- PPCMCCodeEmitter.cpp - Convert PPC code to machine code -----------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements the PPCMCCodeEmitter class.
//
//===----------------------------------------------------------------------===//
#include "MCTargetDesc/PPCFixupKinds.h"
#include "PPCInstrInfo.h"
#include "PPCMCCodeEmitter.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/Triple.h"
#include "llvm/MC/MCFixup.h"
#include "llvm/MC/MCInstrDesc.h"
#include "llvm/MC/MCRegisterInfo.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/EndianStream.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.h"
#include <cassert>
#include <cstdint>
using namespace llvm;
#define DEBUG_TYPE "mccodeemitter"
STATISTIC(MCNumEmitted, "Number of MC instructions emitted");
MCCodeEmitter *llvm::createPPCMCCodeEmitter(const MCInstrInfo &MCII,
const MCRegisterInfo &MRI,
MCContext &Ctx) {
return new PPCMCCodeEmitter(MCII, Ctx);
}
unsigned PPCMCCodeEmitter::
getDirectBrEncoding(const MCInst &MI, unsigned OpNo,
SmallVectorImpl<MCFixup> &Fixups,
const MCSubtargetInfo &STI) const {
const MCOperand &MO = MI.getOperand(OpNo);
if (MO.isReg() || MO.isImm())
return getMachineOpValue(MI, MO, Fixups, STI);
// Add a fixup for the branch target.
Fixups.push_back(MCFixup::create(0, MO.getExpr(),
((MI.getOpcode() == PPC::BL8_NOTOC ||
MI.getOpcode() == PPC::BL8_NOTOC_TLS)
? (MCFixupKind)PPC::fixup_ppc_br24_notoc
: (MCFixupKind)PPC::fixup_ppc_br24)));
return 0;
}
unsigned PPCMCCodeEmitter::getCondBrEncoding(const MCInst &MI, unsigned OpNo,
SmallVectorImpl<MCFixup> &Fixups,
const MCSubtargetInfo &STI) const {
const MCOperand &MO = MI.getOperand(OpNo);
if (MO.isReg() || MO.isImm()) return getMachineOpValue(MI, MO, Fixups, STI);
// Add a fixup for the branch target.
Fixups.push_back(MCFixup::create(0, MO.getExpr(),
(MCFixupKind)PPC::fixup_ppc_brcond14));
return 0;
}
unsigned PPCMCCodeEmitter::
getAbsDirectBrEncoding(const MCInst &MI, unsigned OpNo,
SmallVectorImpl<MCFixup> &Fixups,
const MCSubtargetInfo &STI) const {
const MCOperand &MO = MI.getOperand(OpNo);
if (MO.isReg() || MO.isImm()) return getMachineOpValue(MI, MO, Fixups, STI);
// Add a fixup for the branch target.
Fixups.push_back(MCFixup::create(0, MO.getExpr(),
(MCFixupKind)PPC::fixup_ppc_br24abs));
return 0;
}
unsigned PPCMCCodeEmitter::
getAbsCondBrEncoding(const MCInst &MI, unsigned OpNo,
SmallVectorImpl<MCFixup> &Fixups,
const MCSubtargetInfo &STI) const {
const MCOperand &MO = MI.getOperand(OpNo);
if (MO.isReg() || MO.isImm()) return getMachineOpValue(MI, MO, Fixups, STI);
// Add a fixup for the branch target.
Fixups.push_back(MCFixup::create(0, MO.getExpr(),
(MCFixupKind)PPC::fixup_ppc_brcond14abs));
return 0;
}
unsigned
PPCMCCodeEmitter::getVSRpEvenEncoding(const MCInst &MI, unsigned OpNo,
SmallVectorImpl<MCFixup> &Fixups,
const MCSubtargetInfo &STI) const {
assert(MI.getOperand(OpNo).isReg() && "Operand should be a register");
unsigned RegBits = getMachineOpValue(MI, MI.getOperand(OpNo), Fixups, STI)
<< 1;
return RegBits;
}
unsigned PPCMCCodeEmitter::getImm16Encoding(const MCInst &MI, unsigned OpNo,
SmallVectorImpl<MCFixup> &Fixups,
const MCSubtargetInfo &STI) const {
const MCOperand &MO = MI.getOperand(OpNo);
if (MO.isReg() || MO.isImm()) return getMachineOpValue(MI, MO, Fixups, STI);
// Add a fixup for the immediate field.
Fixups.push_back(MCFixup::create(IsLittleEndian? 0 : 2, MO.getExpr(),
(MCFixupKind)PPC::fixup_ppc_half16));
return 0;
}
uint64_t PPCMCCodeEmitter::getImm34Encoding(const MCInst &MI, unsigned OpNo,
SmallVectorImpl<MCFixup> &Fixups,
const MCSubtargetInfo &STI,
MCFixupKind Fixup) const {
const MCOperand &MO = MI.getOperand(OpNo);
assert(!MO.isReg() && "Not expecting a register for this operand.");
if (MO.isImm())
return getMachineOpValue(MI, MO, Fixups, STI);
// Add a fixup for the immediate field.
Fixups.push_back(MCFixup::create(0, MO.getExpr(), Fixup));
return 0;
}
uint64_t
PPCMCCodeEmitter::getImm34EncodingNoPCRel(const MCInst &MI, unsigned OpNo,
SmallVectorImpl<MCFixup> &Fixups,
const MCSubtargetInfo &STI) const {
return getImm34Encoding(MI, OpNo, Fixups, STI,
(MCFixupKind)PPC::fixup_ppc_imm34);
}
uint64_t
PPCMCCodeEmitter::getImm34EncodingPCRel(const MCInst &MI, unsigned OpNo,
SmallVectorImpl<MCFixup> &Fixups,
const MCSubtargetInfo &STI) const {
return getImm34Encoding(MI, OpNo, Fixups, STI,
(MCFixupKind)PPC::fixup_ppc_pcrel34);
}
unsigned PPCMCCodeEmitter::getMemRIEncoding(const MCInst &MI, unsigned OpNo,
SmallVectorImpl<MCFixup> &Fixups,
const MCSubtargetInfo &STI) 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), Fixups, STI) << 16;
const MCOperand &MO = MI.getOperand(OpNo);
if (MO.isImm())
return (getMachineOpValue(MI, MO, Fixups, STI) & 0xFFFF) | RegBits;
// Add a fixup for the displacement field.
Fixups.push_back(MCFixup::create(IsLittleEndian? 0 : 2, MO.getExpr(),
(MCFixupKind)PPC::fixup_ppc_half16));
return RegBits;
}
unsigned PPCMCCodeEmitter::getMemRIXEncoding(const MCInst &MI, unsigned OpNo,
SmallVectorImpl<MCFixup> &Fixups,
const MCSubtargetInfo &STI) 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), Fixups, STI) << 14;
const MCOperand &MO = MI.getOperand(OpNo);
if (MO.isImm())
return ((getMachineOpValue(MI, MO, Fixups, STI) >> 2) & 0x3FFF) | RegBits;
// Add a fixup for the displacement field.
Fixups.push_back(MCFixup::create(IsLittleEndian? 0 : 2, MO.getExpr(),
(MCFixupKind)PPC::fixup_ppc_half16ds));
return RegBits;
}
unsigned PPCMCCodeEmitter::getMemRIX16Encoding(const MCInst &MI, unsigned OpNo,
SmallVectorImpl<MCFixup> &Fixups,
const MCSubtargetInfo &STI) const {
// Encode (imm, reg) as a memrix16, which has the low 12-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), Fixups, STI) << 12;
const MCOperand &MO = MI.getOperand(OpNo);
if (MO.isImm()) {
assert(!(MO.getImm() % 16) &&
"Expecting an immediate that is a multiple of 16");
return ((getMachineOpValue(MI, MO, Fixups, STI) >> 4) & 0xFFF) | RegBits;
}
// Otherwise add a fixup for the displacement field.
Fixups.push_back(MCFixup::create(IsLittleEndian? 0 : 2, MO.getExpr(),
(MCFixupKind)PPC::fixup_ppc_half16ds));
return RegBits;
}
uint64_t
PPCMCCodeEmitter::getMemRI34PCRelEncoding(const MCInst &MI, unsigned OpNo,
SmallVectorImpl<MCFixup> &Fixups,
const MCSubtargetInfo &STI) const {
// Encode the PCRelative version of memri34: imm34(r0).
// In the PC relative version the register for the address must be zero.
// The 34 bit immediate can fall into one of three cases:
// 1) It is a relocation to be filled in by the linker represented as:
// (MCExpr::SymbolRef)
// 2) It is a relocation + SignedOffset represented as:
// (MCExpr::Binary(MCExpr::SymbolRef + MCExpr::Constant))
// 3) It is a known value at compile time.
// Make sure that the register is a zero as expected.
assert(MI.getOperand(OpNo + 1).isImm() && "Expecting an immediate.");
uint64_t RegBits =
getMachineOpValue(MI, MI.getOperand(OpNo + 1), Fixups, STI) << 34;
assert(RegBits == 0 && "Operand must be 0.");
// If this is not a MCExpr then we are in case 3) and we are dealing with
// a value known at compile time, not a relocation.
const MCOperand &MO = MI.getOperand(OpNo);
if (!MO.isExpr())
return ((getMachineOpValue(MI, MO, Fixups, STI)) & 0x3FFFFFFFFUL) | RegBits;
// At this point in the function it is known that MO is of type MCExpr.
// Therefore we are dealing with either case 1) a symbol ref or
// case 2) a symbol ref plus a constant.
const MCExpr *Expr = MO.getExpr();
switch (Expr->getKind()) {
default:
llvm_unreachable("Unsupported MCExpr for getMemRI34PCRelEncoding.");
case MCExpr::SymbolRef: {
// Relocation alone.
const MCSymbolRefExpr *SRE = cast<MCSymbolRefExpr>(Expr);
(void)SRE;
// Currently these are the only valid PCRelative Relocations.
assert((SRE->getKind() == MCSymbolRefExpr::VK_PCREL ||
SRE->getKind() == MCSymbolRefExpr::VK_PPC_GOT_PCREL ||
SRE->getKind() == MCSymbolRefExpr::VK_PPC_GOT_TLSGD_PCREL ||
SRE->getKind() == MCSymbolRefExpr::VK_PPC_GOT_TLSLD_PCREL ||
SRE->getKind() == MCSymbolRefExpr::VK_PPC_GOT_TPREL_PCREL) &&
"VariantKind must be VK_PCREL or VK_PPC_GOT_PCREL or "
"VK_PPC_GOT_TLSGD_PCREL or VK_PPC_GOT_TLSLD_PCREL or "
"VK_PPC_GOT_TPREL_PCREL.");
// Generate the fixup for the relocation.
Fixups.push_back(
MCFixup::create(0, Expr,
static_cast<MCFixupKind>(PPC::fixup_ppc_pcrel34)));
// Put zero in the location of the immediate. The linker will fill in the
// correct value based on the relocation.
return 0;
}
case MCExpr::Binary: {
// Relocation plus some offset.
const MCBinaryExpr *BE = cast<MCBinaryExpr>(Expr);
assert(BE->getOpcode() == MCBinaryExpr::Add &&
"Binary expression opcode must be an add.");
const MCExpr *LHS = BE->getLHS();
const MCExpr *RHS = BE->getRHS();
// Need to check in both directions. Reloc+Offset and Offset+Reloc.
if (LHS->getKind() != MCExpr::SymbolRef)
std::swap(LHS, RHS);
if (LHS->getKind() != MCExpr::SymbolRef ||
RHS->getKind() != MCExpr::Constant)
llvm_unreachable("Expecting to have one constant and one relocation.");
const MCSymbolRefExpr *SRE = cast<MCSymbolRefExpr>(LHS);
(void)SRE;
assert(isInt<34>(cast<MCConstantExpr>(RHS)->getValue()) &&
"Value must fit in 34 bits.");
// Currently these are the only valid PCRelative Relocations.
assert((SRE->getKind() == MCSymbolRefExpr::VK_PCREL ||
SRE->getKind() == MCSymbolRefExpr::VK_PPC_GOT_PCREL) &&
"VariantKind must be VK_PCREL or VK_PPC_GOT_PCREL");
// Generate the fixup for the relocation.
Fixups.push_back(
MCFixup::create(0, Expr,
static_cast<MCFixupKind>(PPC::fixup_ppc_pcrel34)));
// Put zero in the location of the immediate. The linker will fill in the
// correct value based on the relocation.
return 0;
}
}
}
uint64_t
PPCMCCodeEmitter::getMemRI34Encoding(const MCInst &MI, unsigned OpNo,
SmallVectorImpl<MCFixup> &Fixups,
const MCSubtargetInfo &STI) const {
// Encode (imm, reg) as a memri34, which has the low 34-bits as the
// displacement and the next 5 bits as the register #.
assert(MI.getOperand(OpNo + 1).isReg() && "Expecting a register.");
uint64_t RegBits = getMachineOpValue(MI, MI.getOperand(OpNo + 1), Fixups, STI)
<< 34;
const MCOperand &MO = MI.getOperand(OpNo);
return ((getMachineOpValue(MI, MO, Fixups, STI)) & 0x3FFFFFFFFUL) | RegBits;
}
unsigned PPCMCCodeEmitter::getSPE8DisEncoding(const MCInst &MI, unsigned OpNo,
SmallVectorImpl<MCFixup> &Fixups,
const MCSubtargetInfo &STI)
const {
// Encode (imm, reg) as a spe8dis, which has the low 5-bits of (imm / 8)
// as the displacement and the next 5 bits as the register #.
assert(MI.getOperand(OpNo+1).isReg());
uint32_t RegBits = getMachineOpValue(MI, MI.getOperand(OpNo+1), Fixups, STI) << 5;
const MCOperand &MO = MI.getOperand(OpNo);
assert(MO.isImm());
uint32_t Imm = getMachineOpValue(MI, MO, Fixups, STI) >> 3;
return reverseBits(Imm | RegBits) >> 22;
}
unsigned PPCMCCodeEmitter::getSPE4DisEncoding(const MCInst &MI, unsigned OpNo,
SmallVectorImpl<MCFixup> &Fixups,
const MCSubtargetInfo &STI)
const {
// Encode (imm, reg) as a spe4dis, which has the low 5-bits of (imm / 4)
// as the displacement and the next 5 bits as the register #.
assert(MI.getOperand(OpNo+1).isReg());
uint32_t RegBits = getMachineOpValue(MI, MI.getOperand(OpNo+1), Fixups, STI) << 5;
const MCOperand &MO = MI.getOperand(OpNo);
assert(MO.isImm());
uint32_t Imm = getMachineOpValue(MI, MO, Fixups, STI) >> 2;
return reverseBits(Imm | RegBits) >> 22;
}
unsigned PPCMCCodeEmitter::getSPE2DisEncoding(const MCInst &MI, unsigned OpNo,
SmallVectorImpl<MCFixup> &Fixups,
const MCSubtargetInfo &STI)
const {
// Encode (imm, reg) as a spe2dis, which has the low 5-bits of (imm / 2)
// as the displacement and the next 5 bits as the register #.
assert(MI.getOperand(OpNo+1).isReg());
uint32_t RegBits = getMachineOpValue(MI, MI.getOperand(OpNo+1), Fixups, STI) << 5;
const MCOperand &MO = MI.getOperand(OpNo);
assert(MO.isImm());
uint32_t Imm = getMachineOpValue(MI, MO, Fixups, STI) >> 1;
return reverseBits(Imm | RegBits) >> 22;
}
unsigned PPCMCCodeEmitter::getTLSRegEncoding(const MCInst &MI, unsigned OpNo,
SmallVectorImpl<MCFixup> &Fixups,
const MCSubtargetInfo &STI) const {
const MCOperand &MO = MI.getOperand(OpNo);
if (MO.isReg()) return getMachineOpValue(MI, MO, Fixups, STI);
// Add a fixup for the TLS register, which simply provides a relocation
// hint to the linker that this statement is part of a relocation sequence.
// Return the thread-pointer register's encoding. Add a one byte displacement
// if using PC relative memops.
const MCExpr *Expr = MO.getExpr();
const MCSymbolRefExpr *SRE = cast<MCSymbolRefExpr>(Expr);
bool IsPCRel = SRE->getKind() == MCSymbolRefExpr::VK_PPC_TLS_PCREL;
Fixups.push_back(MCFixup::create(IsPCRel ? 1 : 0, Expr,
(MCFixupKind)PPC::fixup_ppc_nofixup));
const Triple &TT = STI.getTargetTriple();
bool isPPC64 = TT.isPPC64();
return CTX.getRegisterInfo()->getEncodingValue(isPPC64 ? PPC::X13 : PPC::R2);
}
unsigned PPCMCCodeEmitter::getTLSCallEncoding(const MCInst &MI, unsigned OpNo,
SmallVectorImpl<MCFixup> &Fixups,
const MCSubtargetInfo &STI) const {
// For special TLS calls, we need two fixups; one for the branch target
// (__tls_get_addr), which we create via getDirectBrEncoding as usual,
// and one for the TLSGD or TLSLD symbol, which is emitted here.
const MCOperand &MO = MI.getOperand(OpNo+1);
Fixups.push_back(MCFixup::create(0, MO.getExpr(),
(MCFixupKind)PPC::fixup_ppc_nofixup));
return getDirectBrEncoding(MI, OpNo, Fixups, STI);
}
unsigned PPCMCCodeEmitter::
get_crbitm_encoding(const MCInst &MI, unsigned OpNo,
SmallVectorImpl<MCFixup> &Fixups,
const MCSubtargetInfo &STI) const {
const MCOperand &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 >> CTX.getRegisterInfo()->getEncodingValue(MO.getReg());
}
// Get the index for this operand in this instruction. This is needed for
// computing the register number in PPCInstrInfo::getRegNumForOperand() for
// any instructions that use a different numbering scheme for registers in
// different operands.
static unsigned getOpIdxForMO(const MCInst &MI, const MCOperand &MO) {
for (unsigned i = 0; i < MI.getNumOperands(); i++) {
const MCOperand &Op = MI.getOperand(i);
if (&Op == &MO)
return i;
}
llvm_unreachable("This operand is not part of this instruction");
return ~0U; // Silence any warnings about no return.
}
uint64_t PPCMCCodeEmitter::
getMachineOpValue(const MCInst &MI, const MCOperand &MO,
SmallVectorImpl<MCFixup> &Fixups,
const MCSubtargetInfo &STI) 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);
unsigned OpNo = getOpIdxForMO(MI, MO);
unsigned Reg =
PPCInstrInfo::getRegNumForOperand(MCII.get(MI.getOpcode()),
MO.getReg(), OpNo);
return CTX.getRegisterInfo()->getEncodingValue(Reg);
}
assert(MO.isImm() &&
"Relocation required in an instruction that we cannot encode!");
return MO.getImm();
}
void PPCMCCodeEmitter::encodeInstruction(
const MCInst &MI, raw_ostream &OS, SmallVectorImpl<MCFixup> &Fixups,
const MCSubtargetInfo &STI) const {
verifyInstructionPredicates(MI,
computeAvailableFeatures(STI.getFeatureBits()));
uint64_t Bits = getBinaryCodeForInstr(MI, Fixups, STI);
// Output the constant in big/little endian byte order.
unsigned Size = getInstSizeInBytes(MI);
support::endianness E = IsLittleEndian ? support::little : support::big;
switch (Size) {
case 0:
break;
case 4:
support::endian::write<uint32_t>(OS, Bits, E);
break;
case 8:
// If we emit a pair of instructions, the first one is
// always in the top 32 bits, even on little-endian.
support::endian::write<uint32_t>(OS, Bits >> 32, E);
support::endian::write<uint32_t>(OS, Bits, E);
break;
default:
llvm_unreachable("Invalid instruction size");
}
++MCNumEmitted; // Keep track of the # of mi's emitted.
}
// Get the number of bytes used to encode the given MCInst.
unsigned PPCMCCodeEmitter::getInstSizeInBytes(const MCInst &MI) const {
unsigned Opcode = MI.getOpcode();
const MCInstrDesc &Desc = MCII.get(Opcode);
return Desc.getSize();
}
bool PPCMCCodeEmitter::isPrefixedInstruction(const MCInst &MI) const {
unsigned Opcode = MI.getOpcode();
const PPCInstrInfo *InstrInfo = static_cast<const PPCInstrInfo*>(&MCII);
return InstrInfo->isPrefixed(Opcode);
}
#define ENABLE_INSTR_PREDICATE_VERIFIER
#include "PPCGenMCCodeEmitter.inc"