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llvm-project/llvm/lib/Target/Mips/MCTargetDesc/MipsAsmBackend.cpp

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//===-- MipsAsmBackend.cpp - Mips Asm Backend ----------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the MipsAsmBackend class.
//
//===----------------------------------------------------------------------===//
//
#include "MCTargetDesc/MipsFixupKinds.h"
#include "MCTargetDesc/MipsAsmBackend.h"
#include "MCTargetDesc/MipsMCTargetDesc.h"
#include "llvm/MC/MCAsmBackend.h"
#include "llvm/MC/MCAssembler.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCDirectives.h"
#include "llvm/MC/MCELFObjectWriter.h"
#include "llvm/MC/MCFixupKindInfo.h"
#include "llvm/MC/MCObjectWriter.h"
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
// Prepare value for the target space for it
static unsigned adjustFixupValue(const MCFixup &Fixup, uint64_t Value,
MCContext *Ctx = nullptr) {
unsigned Kind = Fixup.getKind();
// Add/subtract and shift
switch (Kind) {
default:
return 0;
case FK_Data_2:
case FK_GPRel_4:
case FK_Data_4:
case FK_Data_8:
case Mips::fixup_Mips_LO16:
case Mips::fixup_Mips_GPREL16:
case Mips::fixup_Mips_GPOFF_HI:
case Mips::fixup_Mips_GPOFF_LO:
case Mips::fixup_Mips_GOT_PAGE:
case Mips::fixup_Mips_GOT_OFST:
case Mips::fixup_Mips_GOT_DISP:
case Mips::fixup_Mips_GOT_LO16:
case Mips::fixup_Mips_CALL_LO16:
case Mips::fixup_MICROMIPS_LO16:
case Mips::fixup_MICROMIPS_GOT_PAGE:
case Mips::fixup_MICROMIPS_GOT_OFST:
case Mips::fixup_MICROMIPS_GOT_DISP:
case Mips::fixup_MIPS_PCLO16:
break;
case Mips::fixup_Mips_PC16:
// So far we are only using this type for branches.
// For branches we start 1 instruction after the branch
// so the displacement will be one instruction size less.
Value -= 4;
// The displacement is then divided by 4 to give us an 18 bit
// address range. Forcing a signed division because Value can be negative.
Value = (int64_t)Value / 4;
// We now check if Value can be encoded as a 16-bit signed immediate.
if (!isIntN(16, Value) && Ctx)
Ctx->FatalError(Fixup.getLoc(), "out of range PC16 fixup");
break;
case Mips::fixup_MIPS_PC19_S2:
// Forcing a signed division because Value can be negative.
Value = (int64_t)Value / 4;
// We now check if Value can be encoded as a 19-bit signed immediate.
if (!isIntN(19, Value) && Ctx)
Ctx->FatalError(Fixup.getLoc(), "out of range PC19 fixup");
break;
case Mips::fixup_Mips_26:
// So far we are only using this type for jumps.
// The displacement is then divided by 4 to give us an 28 bit
// address range.
Value >>= 2;
break;
case Mips::fixup_Mips_HI16:
case Mips::fixup_Mips_GOT_Local:
case Mips::fixup_Mips_GOT_HI16:
case Mips::fixup_Mips_CALL_HI16:
case Mips::fixup_MICROMIPS_HI16:
case Mips::fixup_MIPS_PCHI16:
// Get the 2nd 16-bits. Also add 1 if bit 15 is 1.
Value = ((Value + 0x8000) >> 16) & 0xffff;
break;
case Mips::fixup_Mips_HIGHER:
// Get the 3rd 16-bits.
Value = ((Value + 0x80008000LL) >> 32) & 0xffff;
break;
case Mips::fixup_Mips_HIGHEST:
// Get the 4th 16-bits.
Value = ((Value + 0x800080008000LL) >> 48) & 0xffff;
break;
case Mips::fixup_MICROMIPS_26_S1:
Value >>= 1;
break;
case Mips::fixup_MICROMIPS_PC7_S1:
Value -= 4;
// Forcing a signed division because Value can be negative.
Value = (int64_t) Value / 2;
// We now check if Value can be encoded as a 7-bit signed immediate.
if (!isIntN(7, Value) && Ctx)
Ctx->FatalError(Fixup.getLoc(), "out of range PC7 fixup");
break;
case Mips::fixup_MICROMIPS_PC10_S1:
Value -= 2;
// Forcing a signed division because Value can be negative.
Value = (int64_t) Value / 2;
// We now check if Value can be encoded as a 10-bit signed immediate.
if (!isIntN(10, Value) && Ctx)
Ctx->FatalError(Fixup.getLoc(), "out of range PC10 fixup");
break;
case Mips::fixup_MICROMIPS_PC16_S1:
Value -= 4;
// Forcing a signed division because Value can be negative.
Value = (int64_t)Value / 2;
// We now check if Value can be encoded as a 16-bit signed immediate.
if (!isIntN(16, Value) && Ctx)
Ctx->FatalError(Fixup.getLoc(), "out of range PC16 fixup");
break;
case Mips::fixup_MIPS_PC18_S3:
// Forcing a signed division because Value can be negative.
Value = (int64_t)Value / 8;
// We now check if Value can be encoded as a 18-bit signed immediate.
if (!isIntN(18, Value) && Ctx)
Ctx->FatalError(Fixup.getLoc(), "out of range PC18 fixup");
break;
case Mips::fixup_MIPS_PC21_S2:
Value -= 4;
// Forcing a signed division because Value can be negative.
Value = (int64_t) Value / 4;
// We now check if Value can be encoded as a 21-bit signed immediate.
if (!isIntN(21, Value) && Ctx)
Ctx->FatalError(Fixup.getLoc(), "out of range PC21 fixup");
break;
case Mips::fixup_MIPS_PC26_S2:
Value -= 4;
// Forcing a signed division because Value can be negative.
Value = (int64_t) Value / 4;
// We now check if Value can be encoded as a 26-bit signed immediate.
if (!isIntN(26, Value) && Ctx)
Ctx->FatalError(Fixup.getLoc(), "out of range PC26 fixup");
break;
}
return Value;
}
MCObjectWriter *MipsAsmBackend::createObjectWriter(raw_ostream &OS) const {
return createMipsELFObjectWriter(OS,
MCELFObjectTargetWriter::getOSABI(OSType), IsLittle, Is64Bit);
}
// Little-endian fixup data byte ordering:
// mips32r2: a | b | x | x
// microMIPS: x | x | a | b
static bool needsMMLEByteOrder(unsigned Kind) {
return Kind != Mips::fixup_MICROMIPS_PC10_S1 &&
Kind >= Mips::fixup_MICROMIPS_26_S1 &&
Kind < Mips::LastTargetFixupKind;
}
// Calculate index for microMIPS specific little endian byte order
static unsigned calculateMMLEIndex(unsigned i) {
assert(i <= 3 && "Index out of range!");
return (1 - i / 2) * 2 + i % 2;
}
/// ApplyFixup - Apply the \p Value for given \p Fixup into the provided
/// data fragment, at the offset specified by the fixup and following the
/// fixup kind as appropriate.
void MipsAsmBackend::applyFixup(const MCFixup &Fixup, char *Data,
unsigned DataSize, uint64_t Value,
bool IsPCRel) const {
MCFixupKind Kind = Fixup.getKind();
Value = adjustFixupValue(Fixup, Value);
if (!Value)
return; // Doesn't change encoding.
// Where do we start in the object
unsigned Offset = Fixup.getOffset();
// Number of bytes we need to fixup
unsigned NumBytes = (getFixupKindInfo(Kind).TargetSize + 7) / 8;
// Used to point to big endian bytes
unsigned FullSize;
switch ((unsigned)Kind) {
case FK_Data_2:
case Mips::fixup_Mips_16:
case Mips::fixup_MICROMIPS_PC10_S1:
FullSize = 2;
break;
case FK_Data_8:
case Mips::fixup_Mips_64:
FullSize = 8;
break;
case FK_Data_4:
default:
FullSize = 4;
break;
}
// Grab current value, if any, from bits.
uint64_t CurVal = 0;
bool microMipsLEByteOrder = needsMMLEByteOrder((unsigned) Kind);
for (unsigned i = 0; i != NumBytes; ++i) {
unsigned Idx = IsLittle ? (microMipsLEByteOrder ? calculateMMLEIndex(i)
: i)
: (FullSize - 1 - i);
CurVal |= (uint64_t)((uint8_t)Data[Offset + Idx]) << (i*8);
}
uint64_t Mask = ((uint64_t)(-1) >>
(64 - getFixupKindInfo(Kind).TargetSize));
CurVal |= Value & Mask;
// Write out the fixed up bytes back to the code/data bits.
for (unsigned i = 0; i != NumBytes; ++i) {
unsigned Idx = IsLittle ? (microMipsLEByteOrder ? calculateMMLEIndex(i)
: i)
: (FullSize - 1 - i);
Data[Offset + Idx] = (uint8_t)((CurVal >> (i*8)) & 0xff);
}
}
const MCFixupKindInfo &MipsAsmBackend::
getFixupKindInfo(MCFixupKind Kind) const {
const static MCFixupKindInfo LittleEndianInfos[Mips::NumTargetFixupKinds] = {
// This table *must* be in same the order of fixup_* kinds in
// MipsFixupKinds.h.
//
// name offset bits flags
{ "fixup_Mips_16", 0, 16, 0 },
{ "fixup_Mips_32", 0, 32, 0 },
{ "fixup_Mips_REL32", 0, 32, 0 },
{ "fixup_Mips_26", 0, 26, 0 },
{ "fixup_Mips_HI16", 0, 16, 0 },
{ "fixup_Mips_LO16", 0, 16, 0 },
{ "fixup_Mips_GPREL16", 0, 16, 0 },
{ "fixup_Mips_LITERAL", 0, 16, 0 },
{ "fixup_Mips_GOT_Global", 0, 16, 0 },
{ "fixup_Mips_GOT_Local", 0, 16, 0 },
{ "fixup_Mips_PC16", 0, 16, MCFixupKindInfo::FKF_IsPCRel },
{ "fixup_Mips_CALL16", 0, 16, 0 },
{ "fixup_Mips_GPREL32", 0, 32, 0 },
{ "fixup_Mips_SHIFT5", 6, 5, 0 },
{ "fixup_Mips_SHIFT6", 6, 5, 0 },
{ "fixup_Mips_64", 0, 64, 0 },
{ "fixup_Mips_TLSGD", 0, 16, 0 },
{ "fixup_Mips_GOTTPREL", 0, 16, 0 },
{ "fixup_Mips_TPREL_HI", 0, 16, 0 },
{ "fixup_Mips_TPREL_LO", 0, 16, 0 },
{ "fixup_Mips_TLSLDM", 0, 16, 0 },
{ "fixup_Mips_DTPREL_HI", 0, 16, 0 },
{ "fixup_Mips_DTPREL_LO", 0, 16, 0 },
{ "fixup_Mips_Branch_PCRel", 0, 16, MCFixupKindInfo::FKF_IsPCRel },
{ "fixup_Mips_GPOFF_HI", 0, 16, 0 },
{ "fixup_Mips_GPOFF_LO", 0, 16, 0 },
{ "fixup_Mips_GOT_PAGE", 0, 16, 0 },
{ "fixup_Mips_GOT_OFST", 0, 16, 0 },
{ "fixup_Mips_GOT_DISP", 0, 16, 0 },
{ "fixup_Mips_HIGHER", 0, 16, 0 },
{ "fixup_Mips_HIGHEST", 0, 16, 0 },
{ "fixup_Mips_GOT_HI16", 0, 16, 0 },
{ "fixup_Mips_GOT_LO16", 0, 16, 0 },
{ "fixup_Mips_CALL_HI16", 0, 16, 0 },
{ "fixup_Mips_CALL_LO16", 0, 16, 0 },
{ "fixup_Mips_PC18_S3", 0, 18, MCFixupKindInfo::FKF_IsPCRel },
{ "fixup_MIPS_PC19_S2", 0, 19, MCFixupKindInfo::FKF_IsPCRel },
{ "fixup_MIPS_PC21_S2", 0, 21, MCFixupKindInfo::FKF_IsPCRel },
{ "fixup_MIPS_PC26_S2", 0, 26, MCFixupKindInfo::FKF_IsPCRel },
{ "fixup_MIPS_PCHI16", 0, 16, MCFixupKindInfo::FKF_IsPCRel },
{ "fixup_MIPS_PCLO16", 0, 16, MCFixupKindInfo::FKF_IsPCRel },
{ "fixup_MICROMIPS_26_S1", 0, 26, 0 },
{ "fixup_MICROMIPS_HI16", 0, 16, 0 },
{ "fixup_MICROMIPS_LO16", 0, 16, 0 },
{ "fixup_MICROMIPS_GOT16", 0, 16, 0 },
{ "fixup_MICROMIPS_PC7_S1", 0, 7, MCFixupKindInfo::FKF_IsPCRel },
{ "fixup_MICROMIPS_PC10_S1", 0, 10, MCFixupKindInfo::FKF_IsPCRel },
{ "fixup_MICROMIPS_PC16_S1", 0, 16, MCFixupKindInfo::FKF_IsPCRel },
{ "fixup_MICROMIPS_CALL16", 0, 16, 0 },
{ "fixup_MICROMIPS_GOT_DISP", 0, 16, 0 },
{ "fixup_MICROMIPS_GOT_PAGE", 0, 16, 0 },
{ "fixup_MICROMIPS_GOT_OFST", 0, 16, 0 },
{ "fixup_MICROMIPS_TLS_GD", 0, 16, 0 },
{ "fixup_MICROMIPS_TLS_LDM", 0, 16, 0 },
{ "fixup_MICROMIPS_TLS_DTPREL_HI16", 0, 16, 0 },
{ "fixup_MICROMIPS_TLS_DTPREL_LO16", 0, 16, 0 },
{ "fixup_MICROMIPS_TLS_TPREL_HI16", 0, 16, 0 },
{ "fixup_MICROMIPS_TLS_TPREL_LO16", 0, 16, 0 }
};
const static MCFixupKindInfo BigEndianInfos[Mips::NumTargetFixupKinds] = {
// This table *must* be in same the order of fixup_* kinds in
// MipsFixupKinds.h.
//
// name offset bits flags
{ "fixup_Mips_16", 16, 16, 0 },
{ "fixup_Mips_32", 0, 32, 0 },
{ "fixup_Mips_REL32", 0, 32, 0 },
{ "fixup_Mips_26", 6, 26, 0 },
{ "fixup_Mips_HI16", 16, 16, 0 },
{ "fixup_Mips_LO16", 16, 16, 0 },
{ "fixup_Mips_GPREL16", 16, 16, 0 },
{ "fixup_Mips_LITERAL", 16, 16, 0 },
{ "fixup_Mips_GOT_Global", 16, 16, 0 },
{ "fixup_Mips_GOT_Local", 16, 16, 0 },
{ "fixup_Mips_PC16", 16, 16, MCFixupKindInfo::FKF_IsPCRel },
{ "fixup_Mips_CALL16", 16, 16, 0 },
{ "fixup_Mips_GPREL32", 0, 32, 0 },
{ "fixup_Mips_SHIFT5", 21, 5, 0 },
{ "fixup_Mips_SHIFT6", 21, 5, 0 },
{ "fixup_Mips_64", 0, 64, 0 },
{ "fixup_Mips_TLSGD", 16, 16, 0 },
{ "fixup_Mips_GOTTPREL", 16, 16, 0 },
{ "fixup_Mips_TPREL_HI", 16, 16, 0 },
{ "fixup_Mips_TPREL_LO", 16, 16, 0 },
{ "fixup_Mips_TLSLDM", 16, 16, 0 },
{ "fixup_Mips_DTPREL_HI", 16, 16, 0 },
{ "fixup_Mips_DTPREL_LO", 16, 16, 0 },
{ "fixup_Mips_Branch_PCRel",16, 16, MCFixupKindInfo::FKF_IsPCRel },
{ "fixup_Mips_GPOFF_HI", 16, 16, 0 },
{ "fixup_Mips_GPOFF_LO", 16, 16, 0 },
{ "fixup_Mips_GOT_PAGE", 16, 16, 0 },
{ "fixup_Mips_GOT_OFST", 16, 16, 0 },
{ "fixup_Mips_GOT_DISP", 16, 16, 0 },
{ "fixup_Mips_HIGHER", 16, 16, 0 },
{ "fixup_Mips_HIGHEST", 16, 16, 0 },
{ "fixup_Mips_GOT_HI16", 16, 16, 0 },
{ "fixup_Mips_GOT_LO16", 16, 16, 0 },
{ "fixup_Mips_CALL_HI16", 16, 16, 0 },
{ "fixup_Mips_CALL_LO16", 16, 16, 0 },
{ "fixup_Mips_PC18_S3", 14, 18, MCFixupKindInfo::FKF_IsPCRel },
{ "fixup_MIPS_PC19_S2", 13, 19, MCFixupKindInfo::FKF_IsPCRel },
{ "fixup_MIPS_PC21_S2", 11, 21, MCFixupKindInfo::FKF_IsPCRel },
{ "fixup_MIPS_PC26_S2", 6, 26, MCFixupKindInfo::FKF_IsPCRel },
{ "fixup_MIPS_PCHI16", 16, 16, MCFixupKindInfo::FKF_IsPCRel },
{ "fixup_MIPS_PCLO16", 16, 16, MCFixupKindInfo::FKF_IsPCRel },
{ "fixup_MICROMIPS_26_S1", 6, 26, 0 },
{ "fixup_MICROMIPS_HI16", 16, 16, 0 },
{ "fixup_MICROMIPS_LO16", 16, 16, 0 },
{ "fixup_MICROMIPS_GOT16", 16, 16, 0 },
{ "fixup_MICROMIPS_PC7_S1", 9, 7, MCFixupKindInfo::FKF_IsPCRel },
{ "fixup_MICROMIPS_PC10_S1", 6, 10, MCFixupKindInfo::FKF_IsPCRel },
{ "fixup_MICROMIPS_PC16_S1",16, 16, MCFixupKindInfo::FKF_IsPCRel },
{ "fixup_MICROMIPS_CALL16", 16, 16, 0 },
{ "fixup_MICROMIPS_GOT_DISP", 16, 16, 0 },
{ "fixup_MICROMIPS_GOT_PAGE", 16, 16, 0 },
{ "fixup_MICROMIPS_GOT_OFST", 16, 16, 0 },
{ "fixup_MICROMIPS_TLS_GD", 16, 16, 0 },
{ "fixup_MICROMIPS_TLS_LDM", 16, 16, 0 },
{ "fixup_MICROMIPS_TLS_DTPREL_HI16", 16, 16, 0 },
{ "fixup_MICROMIPS_TLS_DTPREL_LO16", 16, 16, 0 },
{ "fixup_MICROMIPS_TLS_TPREL_HI16", 16, 16, 0 },
{ "fixup_MICROMIPS_TLS_TPREL_LO16", 16, 16, 0 }
};
if (Kind < FirstTargetFixupKind)
return MCAsmBackend::getFixupKindInfo(Kind);
assert(unsigned(Kind - FirstTargetFixupKind) < getNumFixupKinds() &&
"Invalid kind!");
if (IsLittle)
return LittleEndianInfos[Kind - FirstTargetFixupKind];
return BigEndianInfos[Kind - FirstTargetFixupKind];
}
/// WriteNopData - Write an (optimal) nop sequence of Count bytes
/// to the given output. If the target cannot generate such a sequence,
/// it should return an error.
///
/// \return - True on success.
bool MipsAsmBackend::writeNopData(uint64_t Count, MCObjectWriter *OW) const {
// Check for a less than instruction size number of bytes
// FIXME: 16 bit instructions are not handled yet here.
// We shouldn't be using a hard coded number for instruction size.
// If the count is not 4-byte aligned, we must be writing data into the text
// section (otherwise we have unaligned instructions, and thus have far
// bigger problems), so just write zeros instead.
for (uint64_t i = 0, e = Count % 4; i != e; ++i)
OW->Write8(0);
uint64_t NumNops = Count / 4;
for (uint64_t i = 0; i != NumNops; ++i)
OW->Write32(0);
return true;
}
/// processFixupValue - Target hook to process the literal value of a fixup
/// if necessary.
void MipsAsmBackend::processFixupValue(const MCAssembler &Asm,
const MCAsmLayout &Layout,
const MCFixup &Fixup,
const MCFragment *DF,
const MCValue &Target,
uint64_t &Value,
bool &IsResolved) {
// At this point we'll ignore the value returned by adjustFixupValue as
// we are only checking if the fixup can be applied correctly. We have
// access to MCContext from here which allows us to report a fatal error
// with *possibly* a source code location.
(void)adjustFixupValue(Fixup, Value, &Asm.getContext());
}
// MCAsmBackend
MCAsmBackend *llvm::createMipsAsmBackendEL32(const Target &T,
const MCRegisterInfo &MRI,
StringRef TT,
StringRef CPU) {
return new MipsAsmBackend(T, Triple(TT).getOS(),
/*IsLittle*/true, /*Is64Bit*/false);
}
MCAsmBackend *llvm::createMipsAsmBackendEB32(const Target &T,
const MCRegisterInfo &MRI,
StringRef TT,
StringRef CPU) {
return new MipsAsmBackend(T, Triple(TT).getOS(),
/*IsLittle*/false, /*Is64Bit*/false);
}
MCAsmBackend *llvm::createMipsAsmBackendEL64(const Target &T,
const MCRegisterInfo &MRI,
StringRef TT,
StringRef CPU) {
return new MipsAsmBackend(T, Triple(TT).getOS(),
/*IsLittle*/true, /*Is64Bit*/true);
}
MCAsmBackend *llvm::createMipsAsmBackendEB64(const Target &T,
const MCRegisterInfo &MRI,
StringRef TT,
StringRef CPU) {
return new MipsAsmBackend(T, Triple(TT).getOS(),
/*IsLittle*/false, /*Is64Bit*/true);
}
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