Files
clang-p2996/llvm/lib/Target/Mips/MCTargetDesc/MipsAsmBackend.cpp
Oliver Stannard 9be59af3ab [Assembler] Make fatal assembler errors non-fatal
Currently, if the assembler encounters an error after parsing (such as an
out-of-range fixup), it reports this as a fatal error, and so stops after the
first error. However, for most of these there is an obvious way to recover
after emitting the error, such as emitting the fixup with a value of zero. This
means that we can report on all of the errors in a file, not just the first
one. MCContext::reportError records the fact that an error was encountered, so
we won't actually emit an object file with the incorrect contents.

Differential Revision: http://reviews.llvm.org/D14717

llvm-svn: 253328
2015-11-17 10:00:43 +00:00

468 lines
19 KiB
C++

//===-- 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:
// 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 (!isInt<16>(Value) && Ctx) {
Ctx->reportError(Fixup.getLoc(), "out of range PC16 fixup");
return 0;
}
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 (!isInt<19>(Value) && Ctx) {
Ctx->reportError(Fixup.getLoc(), "out of range PC19 fixup");
return 0;
}
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 (!isInt<7>(Value) && Ctx) {
Ctx->reportError(Fixup.getLoc(), "out of range PC7 fixup");
return 0;
}
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 (!isInt<10>(Value) && Ctx) {
Ctx->reportError(Fixup.getLoc(), "out of range PC10 fixup");
return 0;
}
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 (!isInt<16>(Value) && Ctx) {
Ctx->reportError(Fixup.getLoc(), "out of range PC16 fixup");
return 0;
}
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 (!isInt<18>(Value) && Ctx) {
Ctx->reportError(Fixup.getLoc(), "out of range PC18 fixup");
return 0;
}
break;
case Mips::fixup_MIPS_PC21_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 21-bit signed immediate.
if (!isInt<21>(Value) && Ctx) {
Ctx->reportError(Fixup.getLoc(), "out of range PC21 fixup");
return 0;
}
break;
case Mips::fixup_MIPS_PC26_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 26-bit signed immediate.
if (!isInt<26>(Value) && Ctx) {
Ctx->reportError(Fixup.getLoc(), "out of range PC26 fixup");
return 0;
}
break;
}
return Value;
}
MCObjectWriter *
MipsAsmBackend::createObjectWriter(raw_pwrite_stream &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);
}
}
bool MipsAsmBackend::getFixupKind(StringRef Name, MCFixupKind &MappedKind) const {
if (Name == "R_MIPS_NONE") {
MappedKind = (MCFixupKind)Mips::fixup_Mips_NONE;
return true;
}
if (Name == "R_MIPS_32") {
MappedKind = FK_Data_4;
return true;
}
return MCAsmBackend::getFixupKind(Name, MappedKind);
}
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_NONE", 0, 0, 0 },
{ "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_NONE", 0, 0, 0 },
{ "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.
OW->WriteZeros(Count);
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,
const Triple &TT, StringRef CPU) {
return new MipsAsmBackend(T, TT.getOS(), /*IsLittle*/ true,
/*Is64Bit*/ false);
}
MCAsmBackend *llvm::createMipsAsmBackendEB32(const Target &T,
const MCRegisterInfo &MRI,
const Triple &TT, StringRef CPU) {
return new MipsAsmBackend(T, TT.getOS(), /*IsLittle*/ false,
/*Is64Bit*/ false);
}
MCAsmBackend *llvm::createMipsAsmBackendEL64(const Target &T,
const MCRegisterInfo &MRI,
const Triple &TT, StringRef CPU) {
return new MipsAsmBackend(T, TT.getOS(), /*IsLittle*/ true, /*Is64Bit*/ true);
}
MCAsmBackend *llvm::createMipsAsmBackendEB64(const Target &T,
const MCRegisterInfo &MRI,
const Triple &TT, StringRef CPU) {
return new MipsAsmBackend(T, TT.getOS(), /*IsLittle*/ false,
/*Is64Bit*/ true);
}