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

288 lines
7.3 KiB
C++
Raw Normal View History

//===-- MipsMCExpr.cpp - Mips specific MC expression classes --------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "MipsMCExpr.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCAssembler.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCObjectStreamer.h"
[mips] Use MipsMCExpr instead of MCSymbolRefExpr for all relocations. Summary: This is much closer to the way MIPS relocation expressions work (%hi(foo + 2) rather than %hi(foo) + 2) and removes the need for the various bodges in MipsAsmParser::evaluateRelocExpr(). Removing those bodges ensures that the constant stored in MCValue is the full 32 or 64-bit (depending on ABI) offset from the symbol. This will be used to correct the %hi/%lo matching needed to sort the relocation table correctly. As part of this: * Gave MCExpr::print() the ability to omit parenthesis when emitting a symbol reference inside a MipsMCExpr operator like %hi(X). Without this we print things like %lo(($L1)). * %hi(%neg(%gprel(X))) is now three MipsMCExpr's instead of one. Most of the related special cases have been removed or moved to MipsMCExpr. We can remove the rest as we gain support for the less common relocations when they are not part of this specific combination. * Renamed MipsMCExpr::VariantKind and the enum prefix ('VK_') to avoid confusion with MCSymbolRefExpr::VariantKind and its prefix (also 'VK_'). * fixup_Mips_GOT_Local and fixup_Mips_GOT_Global were found to be identical and merged into fixup_Mips_GOT. * MO_GOT16 and MO_GOT turned out to be identical and have been merged into MO_GOT. * VK_Mips_GOT and VK_Mips_GOT16 turned out to be the same thing so they have been merged into MEK_GOT Reviewers: sdardis Subscribers: dsanders, sdardis, llvm-commits Differential Revision: http://reviews.llvm.org/D19716 llvm-svn: 268379
2016-05-03 21:35:44 +08:00
#include "llvm/MC/MCSymbolELF.h"
#include "llvm/Support/ELF.h"
using namespace llvm;
#define DEBUG_TYPE "mipsmcexpr"
[mips] Use MipsMCExpr instead of MCSymbolRefExpr for all relocations. Summary: This is much closer to the way MIPS relocation expressions work (%hi(foo + 2) rather than %hi(foo) + 2) and removes the need for the various bodges in MipsAsmParser::evaluateRelocExpr(). Removing those bodges ensures that the constant stored in MCValue is the full 32 or 64-bit (depending on ABI) offset from the symbol. This will be used to correct the %hi/%lo matching needed to sort the relocation table correctly. As part of this: * Gave MCExpr::print() the ability to omit parenthesis when emitting a symbol reference inside a MipsMCExpr operator like %hi(X). Without this we print things like %lo(($L1)). * %hi(%neg(%gprel(X))) is now three MipsMCExpr's instead of one. Most of the related special cases have been removed or moved to MipsMCExpr. We can remove the rest as we gain support for the less common relocations when they are not part of this specific combination. * Renamed MipsMCExpr::VariantKind and the enum prefix ('VK_') to avoid confusion with MCSymbolRefExpr::VariantKind and its prefix (also 'VK_'). * fixup_Mips_GOT_Local and fixup_Mips_GOT_Global were found to be identical and merged into fixup_Mips_GOT. * MO_GOT16 and MO_GOT turned out to be identical and have been merged into MO_GOT. * VK_Mips_GOT and VK_Mips_GOT16 turned out to be the same thing so they have been merged into MEK_GOT Reviewers: sdardis Subscribers: dsanders, sdardis, llvm-commits Differential Revision: http://reviews.llvm.org/D19716 llvm-svn: 268379
2016-05-03 21:35:44 +08:00
const MipsMCExpr *MipsMCExpr::create(MipsMCExpr::MipsExprKind Kind,
const MCExpr *Expr, MCContext &Ctx) {
return new (Ctx) MipsMCExpr(Kind, Expr);
}
[mips] Use MipsMCExpr instead of MCSymbolRefExpr for all relocations. Summary: This is much closer to the way MIPS relocation expressions work (%hi(foo + 2) rather than %hi(foo) + 2) and removes the need for the various bodges in MipsAsmParser::evaluateRelocExpr(). Removing those bodges ensures that the constant stored in MCValue is the full 32 or 64-bit (depending on ABI) offset from the symbol. This will be used to correct the %hi/%lo matching needed to sort the relocation table correctly. As part of this: * Gave MCExpr::print() the ability to omit parenthesis when emitting a symbol reference inside a MipsMCExpr operator like %hi(X). Without this we print things like %lo(($L1)). * %hi(%neg(%gprel(X))) is now three MipsMCExpr's instead of one. Most of the related special cases have been removed or moved to MipsMCExpr. We can remove the rest as we gain support for the less common relocations when they are not part of this specific combination. * Renamed MipsMCExpr::VariantKind and the enum prefix ('VK_') to avoid confusion with MCSymbolRefExpr::VariantKind and its prefix (also 'VK_'). * fixup_Mips_GOT_Local and fixup_Mips_GOT_Global were found to be identical and merged into fixup_Mips_GOT. * MO_GOT16 and MO_GOT turned out to be identical and have been merged into MO_GOT. * VK_Mips_GOT and VK_Mips_GOT16 turned out to be the same thing so they have been merged into MEK_GOT Reviewers: sdardis Subscribers: dsanders, sdardis, llvm-commits Differential Revision: http://reviews.llvm.org/D19716 llvm-svn: 268379
2016-05-03 21:35:44 +08:00
const MipsMCExpr *MipsMCExpr::createGpOff(MipsMCExpr::MipsExprKind Kind,
const MCExpr *Expr, MCContext &Ctx) {
return create(Kind, create(MEK_NEG, create(MEK_GPREL, Expr, Ctx), Ctx), Ctx);
}
[mips] Use MipsMCExpr instead of MCSymbolRefExpr for all relocations. Summary: This is much closer to the way MIPS relocation expressions work (%hi(foo + 2) rather than %hi(foo) + 2) and removes the need for the various bodges in MipsAsmParser::evaluateRelocExpr(). Removing those bodges ensures that the constant stored in MCValue is the full 32 or 64-bit (depending on ABI) offset from the symbol. This will be used to correct the %hi/%lo matching needed to sort the relocation table correctly. As part of this: * Gave MCExpr::print() the ability to omit parenthesis when emitting a symbol reference inside a MipsMCExpr operator like %hi(X). Without this we print things like %lo(($L1)). * %hi(%neg(%gprel(X))) is now three MipsMCExpr's instead of one. Most of the related special cases have been removed or moved to MipsMCExpr. We can remove the rest as we gain support for the less common relocations when they are not part of this specific combination. * Renamed MipsMCExpr::VariantKind and the enum prefix ('VK_') to avoid confusion with MCSymbolRefExpr::VariantKind and its prefix (also 'VK_'). * fixup_Mips_GOT_Local and fixup_Mips_GOT_Global were found to be identical and merged into fixup_Mips_GOT. * MO_GOT16 and MO_GOT turned out to be identical and have been merged into MO_GOT. * VK_Mips_GOT and VK_Mips_GOT16 turned out to be the same thing so they have been merged into MEK_GOT Reviewers: sdardis Subscribers: dsanders, sdardis, llvm-commits Differential Revision: http://reviews.llvm.org/D19716 llvm-svn: 268379
2016-05-03 21:35:44 +08:00
void MipsMCExpr::printImpl(raw_ostream &OS, const MCAsmInfo *MAI) const {
int64_t AbsVal;
switch (Kind) {
case MEK_None:
case MEK_Special:
llvm_unreachable("MEK_None and MEK_Special are invalid");
break;
[mips] Use MipsMCExpr instead of MCSymbolRefExpr for all relocations. Summary: This is much closer to the way MIPS relocation expressions work (%hi(foo + 2) rather than %hi(foo) + 2) and removes the need for the various bodges in MipsAsmParser::evaluateRelocExpr(). Removing those bodges ensures that the constant stored in MCValue is the full 32 or 64-bit (depending on ABI) offset from the symbol. This will be used to correct the %hi/%lo matching needed to sort the relocation table correctly. As part of this: * Gave MCExpr::print() the ability to omit parenthesis when emitting a symbol reference inside a MipsMCExpr operator like %hi(X). Without this we print things like %lo(($L1)). * %hi(%neg(%gprel(X))) is now three MipsMCExpr's instead of one. Most of the related special cases have been removed or moved to MipsMCExpr. We can remove the rest as we gain support for the less common relocations when they are not part of this specific combination. * Renamed MipsMCExpr::VariantKind and the enum prefix ('VK_') to avoid confusion with MCSymbolRefExpr::VariantKind and its prefix (also 'VK_'). * fixup_Mips_GOT_Local and fixup_Mips_GOT_Global were found to be identical and merged into fixup_Mips_GOT. * MO_GOT16 and MO_GOT turned out to be identical and have been merged into MO_GOT. * VK_Mips_GOT and VK_Mips_GOT16 turned out to be the same thing so they have been merged into MEK_GOT Reviewers: sdardis Subscribers: dsanders, sdardis, llvm-commits Differential Revision: http://reviews.llvm.org/D19716 llvm-svn: 268379
2016-05-03 21:35:44 +08:00
case MEK_CALL_HI16:
OS << "%call_hi";
break;
[mips] Use MipsMCExpr instead of MCSymbolRefExpr for all relocations. Summary: This is much closer to the way MIPS relocation expressions work (%hi(foo + 2) rather than %hi(foo) + 2) and removes the need for the various bodges in MipsAsmParser::evaluateRelocExpr(). Removing those bodges ensures that the constant stored in MCValue is the full 32 or 64-bit (depending on ABI) offset from the symbol. This will be used to correct the %hi/%lo matching needed to sort the relocation table correctly. As part of this: * Gave MCExpr::print() the ability to omit parenthesis when emitting a symbol reference inside a MipsMCExpr operator like %hi(X). Without this we print things like %lo(($L1)). * %hi(%neg(%gprel(X))) is now three MipsMCExpr's instead of one. Most of the related special cases have been removed or moved to MipsMCExpr. We can remove the rest as we gain support for the less common relocations when they are not part of this specific combination. * Renamed MipsMCExpr::VariantKind and the enum prefix ('VK_') to avoid confusion with MCSymbolRefExpr::VariantKind and its prefix (also 'VK_'). * fixup_Mips_GOT_Local and fixup_Mips_GOT_Global were found to be identical and merged into fixup_Mips_GOT. * MO_GOT16 and MO_GOT turned out to be identical and have been merged into MO_GOT. * VK_Mips_GOT and VK_Mips_GOT16 turned out to be the same thing so they have been merged into MEK_GOT Reviewers: sdardis Subscribers: dsanders, sdardis, llvm-commits Differential Revision: http://reviews.llvm.org/D19716 llvm-svn: 268379
2016-05-03 21:35:44 +08:00
case MEK_CALL_LO16:
OS << "%call_lo";
break;
[mips] Use MipsMCExpr instead of MCSymbolRefExpr for all relocations. Summary: This is much closer to the way MIPS relocation expressions work (%hi(foo + 2) rather than %hi(foo) + 2) and removes the need for the various bodges in MipsAsmParser::evaluateRelocExpr(). Removing those bodges ensures that the constant stored in MCValue is the full 32 or 64-bit (depending on ABI) offset from the symbol. This will be used to correct the %hi/%lo matching needed to sort the relocation table correctly. As part of this: * Gave MCExpr::print() the ability to omit parenthesis when emitting a symbol reference inside a MipsMCExpr operator like %hi(X). Without this we print things like %lo(($L1)). * %hi(%neg(%gprel(X))) is now three MipsMCExpr's instead of one. Most of the related special cases have been removed or moved to MipsMCExpr. We can remove the rest as we gain support for the less common relocations when they are not part of this specific combination. * Renamed MipsMCExpr::VariantKind and the enum prefix ('VK_') to avoid confusion with MCSymbolRefExpr::VariantKind and its prefix (also 'VK_'). * fixup_Mips_GOT_Local and fixup_Mips_GOT_Global were found to be identical and merged into fixup_Mips_GOT. * MO_GOT16 and MO_GOT turned out to be identical and have been merged into MO_GOT. * VK_Mips_GOT and VK_Mips_GOT16 turned out to be the same thing so they have been merged into MEK_GOT Reviewers: sdardis Subscribers: dsanders, sdardis, llvm-commits Differential Revision: http://reviews.llvm.org/D19716 llvm-svn: 268379
2016-05-03 21:35:44 +08:00
case MEK_DTPREL_HI:
OS << "%dtprel_hi";
break;
case MEK_DTPREL_LO:
OS << "%dtprel_lo";
break;
case MEK_GOT:
OS << "%got";
break;
case MEK_GOTTPREL:
OS << "%gottprel";
break;
case MEK_GOT_CALL:
OS << "%call16";
break;
case MEK_GOT_DISP:
OS << "%got_disp";
break;
case MEK_GOT_HI16:
OS << "%got_hi";
break;
case MEK_GOT_LO16:
OS << "%got_lo";
break;
case MEK_GOT_PAGE:
OS << "%got_page";
break;
case MEK_GOT_OFST:
OS << "%got_ofst";
break;
case MEK_GPREL:
OS << "%gp_rel";
break;
case MEK_HI:
OS << "%hi";
break;
case MEK_HIGHER:
OS << "%higher";
break;
case MEK_HIGHEST:
OS << "%highest";
break;
case MEK_LO:
OS << "%lo";
break;
case MEK_NEG:
OS << "%neg";
break;
case MEK_PCREL_HI16:
OS << "%pcrel_hi";
break;
case MEK_PCREL_LO16:
OS << "%pcrel_lo";
break;
case MEK_TLSGD:
OS << "%tlsgd";
break;
case MEK_TLSLDM:
OS << "%tlsldm";
break;
case MEK_TPREL_HI:
OS << "%tprel_hi";
break;
case MEK_TPREL_LO:
OS << "%tprel_lo";
break;
}
OS << '(';
[mips] Use MipsMCExpr instead of MCSymbolRefExpr for all relocations. Summary: This is much closer to the way MIPS relocation expressions work (%hi(foo + 2) rather than %hi(foo) + 2) and removes the need for the various bodges in MipsAsmParser::evaluateRelocExpr(). Removing those bodges ensures that the constant stored in MCValue is the full 32 or 64-bit (depending on ABI) offset from the symbol. This will be used to correct the %hi/%lo matching needed to sort the relocation table correctly. As part of this: * Gave MCExpr::print() the ability to omit parenthesis when emitting a symbol reference inside a MipsMCExpr operator like %hi(X). Without this we print things like %lo(($L1)). * %hi(%neg(%gprel(X))) is now three MipsMCExpr's instead of one. Most of the related special cases have been removed or moved to MipsMCExpr. We can remove the rest as we gain support for the less common relocations when they are not part of this specific combination. * Renamed MipsMCExpr::VariantKind and the enum prefix ('VK_') to avoid confusion with MCSymbolRefExpr::VariantKind and its prefix (also 'VK_'). * fixup_Mips_GOT_Local and fixup_Mips_GOT_Global were found to be identical and merged into fixup_Mips_GOT. * MO_GOT16 and MO_GOT turned out to be identical and have been merged into MO_GOT. * VK_Mips_GOT and VK_Mips_GOT16 turned out to be the same thing so they have been merged into MEK_GOT Reviewers: sdardis Subscribers: dsanders, sdardis, llvm-commits Differential Revision: http://reviews.llvm.org/D19716 llvm-svn: 268379
2016-05-03 21:35:44 +08:00
if (Expr->evaluateAsAbsolute(AbsVal))
OS << AbsVal;
else
Expr->print(OS, MAI, true);
OS << ')';
}
bool
MipsMCExpr::evaluateAsRelocatableImpl(MCValue &Res,
const MCAsmLayout *Layout,
const MCFixup *Fixup) const {
[mips] Use MipsMCExpr instead of MCSymbolRefExpr for all relocations. Summary: This is much closer to the way MIPS relocation expressions work (%hi(foo + 2) rather than %hi(foo) + 2) and removes the need for the various bodges in MipsAsmParser::evaluateRelocExpr(). Removing those bodges ensures that the constant stored in MCValue is the full 32 or 64-bit (depending on ABI) offset from the symbol. This will be used to correct the %hi/%lo matching needed to sort the relocation table correctly. As part of this: * Gave MCExpr::print() the ability to omit parenthesis when emitting a symbol reference inside a MipsMCExpr operator like %hi(X). Without this we print things like %lo(($L1)). * %hi(%neg(%gprel(X))) is now three MipsMCExpr's instead of one. Most of the related special cases have been removed or moved to MipsMCExpr. We can remove the rest as we gain support for the less common relocations when they are not part of this specific combination. * Renamed MipsMCExpr::VariantKind and the enum prefix ('VK_') to avoid confusion with MCSymbolRefExpr::VariantKind and its prefix (also 'VK_'). * fixup_Mips_GOT_Local and fixup_Mips_GOT_Global were found to be identical and merged into fixup_Mips_GOT. * MO_GOT16 and MO_GOT turned out to be identical and have been merged into MO_GOT. * VK_Mips_GOT and VK_Mips_GOT16 turned out to be the same thing so they have been merged into MEK_GOT Reviewers: sdardis Subscribers: dsanders, sdardis, llvm-commits Differential Revision: http://reviews.llvm.org/D19716 llvm-svn: 268379
2016-05-03 21:35:44 +08:00
// Look for the %hi(%neg(%gp_rel(X))) and %lo(%neg(%gp_rel(X))) special cases.
if (isGpOff()) {
const MCExpr *SubExpr =
cast<MipsMCExpr>(cast<MipsMCExpr>(getSubExpr())->getSubExpr())
->getSubExpr();
if (!SubExpr->evaluateAsRelocatable(Res, Layout, Fixup))
return false;
Res = MCValue::get(Res.getSymA(), Res.getSymB(), Res.getConstant(),
MEK_Special);
return true;
}
if (!getSubExpr()->evaluateAsRelocatable(Res, Layout, Fixup))
return false;
if (Res.getRefKind() != MCSymbolRefExpr::VK_None)
return false;
// evaluateAsAbsolute() and evaluateAsValue() require that we evaluate the
// %hi/%lo/etc. here. Fixup is a null pointer when either of these is the
// caller.
if (Res.isAbsolute() && Fixup == nullptr) {
int64_t AbsVal = Res.getConstant();
switch (Kind) {
case MEK_None:
case MEK_Special:
llvm_unreachable("MEK_None and MEK_Special are invalid");
case MEK_DTPREL_HI:
case MEK_DTPREL_LO:
case MEK_GOT:
case MEK_GOTTPREL:
case MEK_GOT_CALL:
case MEK_GOT_DISP:
case MEK_GOT_HI16:
case MEK_GOT_LO16:
case MEK_GOT_OFST:
case MEK_GOT_PAGE:
case MEK_GPREL:
case MEK_PCREL_HI16:
case MEK_PCREL_LO16:
case MEK_TLSGD:
case MEK_TLSLDM:
case MEK_TPREL_HI:
case MEK_TPREL_LO:
return false;
case MEK_LO:
case MEK_CALL_LO16:
AbsVal = SignExtend64<16>(AbsVal);
break;
case MEK_CALL_HI16:
case MEK_HI:
AbsVal = SignExtend64<16>((AbsVal + 0x8000) >> 16);
break;
case MEK_HIGHER:
AbsVal = SignExtend64<16>((AbsVal + 0x80008000LL) >> 32);
break;
case MEK_HIGHEST:
AbsVal = SignExtend64<16>((AbsVal + 0x800080008000LL) >> 48);
break;
case MEK_NEG:
AbsVal = -AbsVal;
break;
}
Res = MCValue::get(AbsVal);
return true;
}
// We want to defer it for relocatable expressions since the constant is
// applied to the whole symbol value.
//
// The value of getKind() that is given to MCValue is only intended to aid
// debugging when inspecting MCValue objects. It shouldn't be relied upon
// for decision making.
Res = MCValue::get(Res.getSymA(), Res.getSymB(), Res.getConstant(), getKind());
return true;
}
void MipsMCExpr::visitUsedExpr(MCStreamer &Streamer) const {
Streamer.visitUsedExpr(*getSubExpr());
}
[mips] Use MipsMCExpr instead of MCSymbolRefExpr for all relocations. Summary: This is much closer to the way MIPS relocation expressions work (%hi(foo + 2) rather than %hi(foo) + 2) and removes the need for the various bodges in MipsAsmParser::evaluateRelocExpr(). Removing those bodges ensures that the constant stored in MCValue is the full 32 or 64-bit (depending on ABI) offset from the symbol. This will be used to correct the %hi/%lo matching needed to sort the relocation table correctly. As part of this: * Gave MCExpr::print() the ability to omit parenthesis when emitting a symbol reference inside a MipsMCExpr operator like %hi(X). Without this we print things like %lo(($L1)). * %hi(%neg(%gprel(X))) is now three MipsMCExpr's instead of one. Most of the related special cases have been removed or moved to MipsMCExpr. We can remove the rest as we gain support for the less common relocations when they are not part of this specific combination. * Renamed MipsMCExpr::VariantKind and the enum prefix ('VK_') to avoid confusion with MCSymbolRefExpr::VariantKind and its prefix (also 'VK_'). * fixup_Mips_GOT_Local and fixup_Mips_GOT_Global were found to be identical and merged into fixup_Mips_GOT. * MO_GOT16 and MO_GOT turned out to be identical and have been merged into MO_GOT. * VK_Mips_GOT and VK_Mips_GOT16 turned out to be the same thing so they have been merged into MEK_GOT Reviewers: sdardis Subscribers: dsanders, sdardis, llvm-commits Differential Revision: http://reviews.llvm.org/D19716 llvm-svn: 268379
2016-05-03 21:35:44 +08:00
static void fixELFSymbolsInTLSFixupsImpl(const MCExpr *Expr, MCAssembler &Asm) {
switch (Expr->getKind()) {
case MCExpr::Target:
fixELFSymbolsInTLSFixupsImpl(cast<MipsMCExpr>(Expr)->getSubExpr(), Asm);
break;
case MCExpr::Constant:
break;
case MCExpr::Binary: {
const MCBinaryExpr *BE = cast<MCBinaryExpr>(Expr);
fixELFSymbolsInTLSFixupsImpl(BE->getLHS(), Asm);
fixELFSymbolsInTLSFixupsImpl(BE->getRHS(), Asm);
break;
}
case MCExpr::SymbolRef: {
// We're known to be under a TLS fixup, so any symbol should be
// modified. There should be only one.
const MCSymbolRefExpr &SymRef = *cast<MCSymbolRefExpr>(Expr);
cast<MCSymbolELF>(SymRef.getSymbol()).setType(ELF::STT_TLS);
break;
}
case MCExpr::Unary:
fixELFSymbolsInTLSFixupsImpl(cast<MCUnaryExpr>(Expr)->getSubExpr(), Asm);
break;
}
}
void MipsMCExpr::fixELFSymbolsInTLSFixups(MCAssembler &Asm) const {
switch (getKind()) {
case MEK_None:
case MEK_Special:
llvm_unreachable("MEK_None and MEK_Special are invalid");
break;
case MEK_CALL_HI16:
case MEK_CALL_LO16:
case MEK_DTPREL_HI:
case MEK_DTPREL_LO:
case MEK_GOT:
case MEK_GOT_CALL:
case MEK_GOT_DISP:
case MEK_GOT_HI16:
case MEK_GOT_LO16:
case MEK_GOT_OFST:
case MEK_GOT_PAGE:
case MEK_GPREL:
case MEK_HI:
case MEK_HIGHER:
case MEK_HIGHEST:
case MEK_LO:
case MEK_NEG:
case MEK_PCREL_HI16:
case MEK_PCREL_LO16:
case MEK_TLSLDM:
// If we do have nested target-specific expressions, they will be in
// a consecutive chain.
if (const MipsMCExpr *E = dyn_cast<const MipsMCExpr>(getSubExpr()))
E->fixELFSymbolsInTLSFixups(Asm);
break;
case MEK_GOTTPREL:
case MEK_TLSGD:
case MEK_TPREL_HI:
case MEK_TPREL_LO:
fixELFSymbolsInTLSFixupsImpl(getSubExpr(), Asm);
break;
}
}
bool MipsMCExpr::isGpOff(MipsExprKind &Kind) const {
if (getKind() == MEK_HI || getKind() == MEK_LO) {
if (const MipsMCExpr *S1 = dyn_cast<const MipsMCExpr>(getSubExpr())) {
if (const MipsMCExpr *S2 = dyn_cast<const MipsMCExpr>(S1->getSubExpr())) {
if (S1->getKind() == MEK_NEG && S2->getKind() == MEK_GPREL) {
Kind = getKind();
return true;
}
}
}
}
return false;
}