CSKYTargetStreamer.cpp

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//===-- CSKYTargetStreamer.h - CSKY Target Streamer ----------*- C++ -*----===//
//
// 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 "CSKYTargetStreamer.h"
#include "MCTargetDesc/CSKYMCAsmInfo.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/TargetSubtargetInfo.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCSectionELF.h"
#include "llvm/Support/FormattedStream.h"
 
using namespace llvm;
 
//
// ConstantPool implementation
//
// Emit the contents of the constant pool using the provided streamer.
void CSKYConstantPool::emitAll(MCStreamer &Streamer) {
  if (Entries.empty())
    return;
 
  if (CurrentSection != nullptr)
    Streamer.switchSection(CurrentSection);
 
  Streamer.emitDataRegion(MCDR_DataRegion);
  for (const ConstantPoolEntry &Entry : Entries) {
    Streamer.emitCodeAlignment(
        Align(Entry.Size),
        Streamer.getContext().getSubtargetInfo()); // align naturally
    Streamer.emitLabel(Entry.Label);
    Streamer.emitValue(Entry.Value, Entry.Size, Entry.Loc);
  }
  Streamer.emitDataRegion(MCDR_DataRegionEnd);
  Entries.clear();
}
 
const MCExpr *CSKYConstantPool::addEntry(MCStreamer &Streamer,
                                         const MCExpr *Value, unsigned Size,
                                         SMLoc Loc, const MCExpr *AdjustExpr) {
  if (CurrentSection == nullptr)
    CurrentSection = Streamer.getCurrentSectionOnly();
 
  auto &Context = Streamer.getContext();
 
  const MCConstantExpr *C = dyn_cast<MCConstantExpr>(Value);
 
  // Check if there is existing entry for the same constant. If so, reuse it.
  auto Itr = C ? CachedEntries.find(C->getValue()) : CachedEntries.end();
  if (Itr != CachedEntries.end())
    return Itr->second;
 
  MCSymbol *CPEntryLabel = Context.createTempSymbol();
  const auto SymRef = MCSymbolRefExpr::create(CPEntryLabel, Context);
 
  if (AdjustExpr) {
    auto *CSKYExpr = cast<MCSpecifierExpr>(Value);
 
    Value = MCBinaryExpr::createSub(AdjustExpr, SymRef, Context);
    Value = MCBinaryExpr::createSub(CSKYExpr->getSubExpr(), Value, Context);
    Value = MCSpecifierExpr::create(Value, CSKYExpr->getSpecifier(), Context);
  }
 
  Entries.push_back(ConstantPoolEntry(CPEntryLabel, Value, Size, Loc));
 
  if (C)
    CachedEntries[C->getValue()] = SymRef;
  return SymRef;
}
 
bool CSKYConstantPool::empty() { return Entries.empty(); }
 
void CSKYConstantPool::clearCache() {
  CurrentSection = nullptr;
  CachedEntries.clear();
}
 
CSKYTargetStreamer::CSKYTargetStreamer(MCStreamer &S)
    : MCTargetStreamer(S), ConstantPool(new CSKYConstantPool()) {}
 
const MCExpr *
CSKYTargetStreamer::addConstantPoolEntry(const MCExpr *Expr, SMLoc Loc,
                                         const MCExpr *AdjustExpr) {
  uint8_t ELFRefKind = CSKY::S_Invalid;
  ConstantCounter++;
 
  const MCExpr *OrigExpr = Expr;
 
  if (auto *CE = dyn_cast<MCSpecifierExpr>(Expr)) {
    Expr = CE->getSubExpr();
    ELFRefKind = CE->getSpecifier();
  }
 
  if (const MCSymbolRefExpr *SymExpr = dyn_cast<MCSymbolRefExpr>(Expr)) {
    const MCSymbol *Sym = &SymExpr->getSymbol();
 
    SymbolIndex Index = {Sym, ELFRefKind};
 
    if (ConstantMap.find(Index) == ConstantMap.end()) {
      ConstantMap[Index] =
          ConstantPool->addEntry(getStreamer(), OrigExpr, 4, Loc, AdjustExpr);
    }
    return ConstantMap[Index];
  }
 
  return ConstantPool->addEntry(getStreamer(), Expr, 4, Loc, AdjustExpr);
}
 
void CSKYTargetStreamer::emitCurrentConstantPool() {
  ConstantPool->emitAll(Streamer);
  ConstantPool->clearCache();
}
 
// finish() - write out any non-empty assembler constant pools.
void CSKYTargetStreamer::finish() {
  if (ConstantCounter != 0) {
    ConstantPool->emitAll(Streamer);
  }
 
  finishAttributeSection();
}
 
void CSKYTargetStreamer::emitTargetAttributes(const MCSubtargetInfo &STI) {}
 
void CSKYTargetStreamer::emitAttribute(unsigned Attribute, unsigned Value) {}
void CSKYTargetStreamer::emitTextAttribute(unsigned Attribute,
                                           StringRef String) {}
void CSKYTargetStreamer::finishAttributeSection() {}
 
void CSKYTargetAsmStreamer::emitAttribute(unsigned Attribute, unsigned Value) {
  OS << "\t.csky_attribute\t" << Attribute << ", " << Twine(Value) << "\n";
}
 
void CSKYTargetAsmStreamer::emitTextAttribute(unsigned Attribute,
                                              StringRef String) {
  OS << "\t.csky_attribute\t" << Attribute << ", \"" << String << "\"\n";
}
 
void CSKYTargetAsmStreamer::finishAttributeSection() {}