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//===- ConstantPools.cpp - ConstantPool class -----------------------------===//
//
// 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 implements the ConstantPool and AssemblerConstantPools classes.
//
//===----------------------------------------------------------------------===//
#include "llvm/MC/ConstantPools.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCDirectives.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/Support/Casting.h"
using namespace llvm;
//
// ConstantPool implementation
//
// Emit the contents of the constant pool using the provided streamer.
void ConstantPool::emitEntries(MCStreamer &Streamer) {
if (Entries.empty())
return;
Streamer.emitDataRegion(MCDR_DataRegion);
for (const ConstantPoolEntry &Entry : Entries) {
Streamer.emitValueToAlignment(Align(Entry.Size)); // align naturally
Streamer.emitLabel(Entry.Label);
Streamer.emitValue(Entry.Value, Entry.Size, Entry.Loc);
}
Streamer.emitDataRegion(MCDR_DataRegionEnd);
Entries.clear();
}
const MCExpr *ConstantPool::addEntry(const MCExpr *Value, MCContext &Context,
unsigned Size, SMLoc Loc) {
const MCConstantExpr *C = dyn_cast<MCConstantExpr>(Value);
const MCSymbolRefExpr *S = dyn_cast<MCSymbolRefExpr>(Value);
// Check if there is existing entry for the same constant. If so, reuse it.
if (C) {
auto CItr = CachedConstantEntries.find(C->getValue());
if (CItr != CachedConstantEntries.end())
return CItr->second;
}
// Check if there is existing entry for the same symbol. If so, reuse it.
if (S) {
auto SItr = CachedSymbolEntries.find(&(S->getSymbol()));
if (SItr != CachedSymbolEntries.end())
return SItr->second;
}
MCSymbol *CPEntryLabel = Context.createTempSymbol();
Entries.push_back(ConstantPoolEntry(CPEntryLabel, Value, Size, Loc));
const auto SymRef = MCSymbolRefExpr::create(CPEntryLabel, Context);
if (C)
CachedConstantEntries[C->getValue()] = SymRef;
if (S)
CachedSymbolEntries[&(S->getSymbol())] = SymRef;
return SymRef;
}
bool ConstantPool::empty() { return Entries.empty(); }
void ConstantPool::clearCache() {
CachedConstantEntries.clear();
CachedSymbolEntries.clear();
}
//
// AssemblerConstantPools implementation
//
ConstantPool *AssemblerConstantPools::getConstantPool(MCSection *Section) {
ConstantPoolMapTy::iterator CP = ConstantPools.find(Section);
if (CP == ConstantPools.end())
return nullptr;
return &CP->second;
}
ConstantPool &
AssemblerConstantPools::getOrCreateConstantPool(MCSection *Section) {
return ConstantPools[Section];
}
static void emitConstantPool(MCStreamer &Streamer, MCSection *Section,
ConstantPool &CP) {
if (!CP.empty()) {
Streamer.switchSection(Section);
CP.emitEntries(Streamer);
}
}
void AssemblerConstantPools::emitAll(MCStreamer &Streamer) {
// Dump contents of assembler constant pools.
for (auto &CPI : ConstantPools) {
MCSection *Section = CPI.first;
ConstantPool &CP = CPI.second;
emitConstantPool(Streamer, Section, CP);
}
}
void AssemblerConstantPools::emitForCurrentSection(MCStreamer &Streamer) {
MCSection *Section = Streamer.getCurrentSectionOnly();
if (ConstantPool *CP = getConstantPool(Section))
emitConstantPool(Streamer, Section, *CP);
}
void AssemblerConstantPools::clearCacheForCurrentSection(MCStreamer &Streamer) {
MCSection *Section = Streamer.getCurrentSectionOnly();
if (ConstantPool *CP = getConstantPool(Section))
CP->clearCache();
}
const MCExpr *AssemblerConstantPools::addEntry(MCStreamer &Streamer,
const MCExpr *Expr,
unsigned Size, SMLoc Loc) {
MCSection *Section = Streamer.getCurrentSectionOnly();
return getOrCreateConstantPool(Section).addEntry(Expr, Streamer.getContext(),
Size, Loc);
}
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