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//===-- RISCVMCExpr.cpp - RISCV 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
//
//===----------------------------------------------------------------------===//
//
// This file contains the implementation of the assembly expression modifiers
// accepted by the RISCV architecture (e.g. ":lo12:", ":gottprel_g1:", ...).
//
//===----------------------------------------------------------------------===//
#include "RISCVMCExpr.h"
#include "MCTargetDesc/RISCVAsmBackend.h"
#include "RISCV.h"
#include "RISCVFixupKinds.h"
#include "llvm/BinaryFormat/ELF.h"
#include "llvm/MC/MCAsmLayout.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/ErrorHandling.h"
using namespace llvm;
#define DEBUG_TYPE "riscvmcexpr"
const RISCVMCExpr *RISCVMCExpr::create(const MCExpr *Expr, VariantKind Kind,
MCContext &Ctx) {
return new (Ctx) RISCVMCExpr(Expr, Kind);
}
void RISCVMCExpr::printImpl(raw_ostream &OS, const MCAsmInfo *MAI) const {
VariantKind Kind = getKind();
bool HasVariant = ((Kind != VK_RISCV_None) && (Kind != VK_RISCV_CALL) &&
(Kind != VK_RISCV_CALL_PLT));
if (HasVariant)
OS << '%' << getVariantKindName(getKind()) << '(';
Expr->print(OS, MAI);
if (Kind == VK_RISCV_CALL_PLT)
OS << "@plt";
if (HasVariant)
OS << ')';
}
const MCFixup *RISCVMCExpr::getPCRelHiFixup(const MCFragment **DFOut) const {
MCValue AUIPCLoc;
if (!getSubExpr()->evaluateAsRelocatable(AUIPCLoc, nullptr, nullptr))
return nullptr;
const MCSymbolRefExpr *AUIPCSRE = AUIPCLoc.getSymA();
if (!AUIPCSRE)
return nullptr;
const MCSymbol *AUIPCSymbol = &AUIPCSRE->getSymbol();
const auto *DF = dyn_cast_or_null<MCDataFragment>(AUIPCSymbol->getFragment());
if (!DF)
return nullptr;
uint64_t Offset = AUIPCSymbol->getOffset();
if (DF->getContents().size() == Offset) {
DF = dyn_cast_or_null<MCDataFragment>(DF->getNextNode());
if (!DF)
return nullptr;
Offset = 0;
}
for (const MCFixup &F : DF->getFixups()) {
if (F.getOffset() != Offset)
continue;
switch ((unsigned)F.getKind()) {
default:
continue;
case RISCV::fixup_riscv_got_hi20:
case RISCV::fixup_riscv_tls_got_hi20:
case RISCV::fixup_riscv_tls_gd_hi20:
case RISCV::fixup_riscv_pcrel_hi20:
if (DFOut)
*DFOut = DF;
return &F;
}
}
return nullptr;
}
bool RISCVMCExpr::evaluateAsRelocatableImpl(MCValue &Res,
const MCAsmLayout *Layout,
const MCFixup *Fixup) const {
if (!getSubExpr()->evaluateAsRelocatable(Res, Layout, Fixup))
return false;
// Some custom fixup types are not valid with symbol difference expressions
if (Res.getSymA() && Res.getSymB()) {
switch (getKind()) {
default:
return true;
case VK_RISCV_LO:
case VK_RISCV_HI:
case VK_RISCV_PCREL_LO:
case VK_RISCV_PCREL_HI:
case VK_RISCV_GOT_HI:
case VK_RISCV_TPREL_LO:
case VK_RISCV_TPREL_HI:
case VK_RISCV_TPREL_ADD:
case VK_RISCV_TLS_GOT_HI:
case VK_RISCV_TLS_GD_HI:
return false;
}
}
return true;
}
void RISCVMCExpr::visitUsedExpr(MCStreamer &Streamer) const {
Streamer.visitUsedExpr(*getSubExpr());
}
RISCVMCExpr::VariantKind RISCVMCExpr::getVariantKindForName(StringRef name) {
return StringSwitch<RISCVMCExpr::VariantKind>(name)
.Case("lo", VK_RISCV_LO)
.Case("hi", VK_RISCV_HI)
.Case("pcrel_lo", VK_RISCV_PCREL_LO)
.Case("pcrel_hi", VK_RISCV_PCREL_HI)
.Case("got_pcrel_hi", VK_RISCV_GOT_HI)
.Case("tprel_lo", VK_RISCV_TPREL_LO)
.Case("tprel_hi", VK_RISCV_TPREL_HI)
.Case("tprel_add", VK_RISCV_TPREL_ADD)
.Case("tls_ie_pcrel_hi", VK_RISCV_TLS_GOT_HI)
.Case("tls_gd_pcrel_hi", VK_RISCV_TLS_GD_HI)
.Default(VK_RISCV_Invalid);
}
StringRef RISCVMCExpr::getVariantKindName(VariantKind Kind) {
switch (Kind) {
default:
llvm_unreachable("Invalid ELF symbol kind");
case VK_RISCV_LO:
return "lo";
case VK_RISCV_HI:
return "hi";
case VK_RISCV_PCREL_LO:
return "pcrel_lo";
case VK_RISCV_PCREL_HI:
return "pcrel_hi";
case VK_RISCV_GOT_HI:
return "got_pcrel_hi";
case VK_RISCV_TPREL_LO:
return "tprel_lo";
case VK_RISCV_TPREL_HI:
return "tprel_hi";
case VK_RISCV_TPREL_ADD:
return "tprel_add";
case VK_RISCV_TLS_GOT_HI:
return "tls_ie_pcrel_hi";
case VK_RISCV_TLS_GD_HI:
return "tls_gd_pcrel_hi";
}
}
static void fixELFSymbolsInTLSFixupsImpl(const MCExpr *Expr, MCAssembler &Asm) {
switch (Expr->getKind()) {
case MCExpr::Target:
llvm_unreachable("Can't handle nested target expression");
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 RISCVMCExpr::fixELFSymbolsInTLSFixups(MCAssembler &Asm) const {
switch (getKind()) {
default:
return;
case VK_RISCV_TPREL_HI:
case VK_RISCV_TLS_GOT_HI:
case VK_RISCV_TLS_GD_HI:
break;
}
fixELFSymbolsInTLSFixupsImpl(getSubExpr(), Asm);
}
bool RISCVMCExpr::evaluateAsConstant(int64_t &Res) const {
MCValue Value;
if (Kind == VK_RISCV_PCREL_HI || Kind == VK_RISCV_PCREL_LO ||
Kind == VK_RISCV_GOT_HI || Kind == VK_RISCV_TPREL_HI ||
Kind == VK_RISCV_TPREL_LO || Kind == VK_RISCV_TPREL_ADD ||
Kind == VK_RISCV_TLS_GOT_HI || Kind == VK_RISCV_TLS_GD_HI ||
Kind == VK_RISCV_CALL || Kind == VK_RISCV_CALL_PLT)
return false;
if (!getSubExpr()->evaluateAsRelocatable(Value, nullptr, nullptr))
return false;
if (!Value.isAbsolute())
return false;
Res = evaluateAsInt64(Value.getConstant());
return true;
}
int64_t RISCVMCExpr::evaluateAsInt64(int64_t Value) const {
switch (Kind) {
default:
llvm_unreachable("Invalid kind");
case VK_RISCV_LO:
return SignExtend64<12>(Value);
case VK_RISCV_HI:
// Add 1 if bit 11 is 1, to compensate for low 12 bits being negative.
return ((Value + 0x800) >> 12) & 0xfffff;
}
}