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//===-- MipsMCExpr.cpp - Mips specific MC expression classes --------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
#include "MipsMCExpr.h"
#include "llvm/BinaryFormat/ELF.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCAssembler.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSymbolELF.h"
#include "llvm/MC/MCValue.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.h"
#include <cstdint>
using namespace llvm;
#define DEBUG_TYPE "mipsmcexpr"
const MipsMCExpr *MipsMCExpr::create(MipsMCExpr::MipsExprKind Kind,
const MCExpr *Expr, MCContext &Ctx) {
return new (Ctx) MipsMCExpr(Kind, Expr);
}
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);
}
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;
case MEK_DTPREL:
// MEK_DTPREL is used for marking TLS DIEExpr only
// and contains a regular sub-expression.
getSubExpr()->print(OS, MAI, true);
return;
case MEK_CALL_HI16:
OS << "%call_hi";
break;
case MEK_CALL_LO16:
OS << "%call_lo";
break;
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 << '(';
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 {
// 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:
// MEK_DTPREL is used for marking TLS DIEExpr only
// and contains a regular sub-expression.
return getSubExpr()->evaluateAsRelocatable(Res, Layout, Fixup);
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());
}
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_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:
// 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_DTPREL:
case MEK_DTPREL_HI:
case MEK_DTPREL_LO:
case MEK_TLSLDM:
case MEK_TLSGD:
case MEK_GOTTPREL:
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;
}
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