llvm-project/llvm/lib/Target/RISCV/MCTargetDesc/RISCVMCExpr.cpp

104 lines
3.0 KiB
C++

//===-- RISCVMCExpr.cpp - RISCV 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.
//
//===----------------------------------------------------------------------===//
//
// This file contains the implementation of the assembly expression modifiers
// accepted by the RISCV architecture (e.g. ":lo12:", ":gottprel_g1:", ...).
//
//===----------------------------------------------------------------------===//
#include "RISCV.h"
#include "RISCVMCExpr.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/Object/ELF.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 {
bool HasVariant = getKind() != VK_RISCV_None;
if (HasVariant)
OS << '%' << getVariantKindName(getKind()) << '(';
Expr->print(OS, MAI);
if (HasVariant)
OS << ')';
}
bool RISCVMCExpr::evaluateAsRelocatableImpl(MCValue &Res,
const MCAsmLayout *Layout,
const MCFixup *Fixup) const {
return getSubExpr()->evaluateAsRelocatable(Res, Layout, Fixup);
}
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)
.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";
}
}
bool RISCVMCExpr::evaluateAsConstant(int64_t &Res) const {
MCValue Value;
if (Kind == VK_RISCV_PCREL_HI || Kind == VK_RISCV_PCREL_LO)
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;
}
}