130 lines · cpp
1//===- ConstantPools.cpp - ConstantPool class -----------------------------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8//9// This file implements the ConstantPool and AssemblerConstantPools classes.10//11//===----------------------------------------------------------------------===//12 13#include "llvm/MC/ConstantPools.h"14#include "llvm/MC/MCContext.h"15#include "llvm/MC/MCDirectives.h"16#include "llvm/MC/MCExpr.h"17#include "llvm/MC/MCStreamer.h"18#include "llvm/Support/Casting.h"19 20using namespace llvm;21 22//23// ConstantPool implementation24//25// Emit the contents of the constant pool using the provided streamer.26void ConstantPool::emitEntries(MCStreamer &Streamer) {27 if (Entries.empty())28 return;29 Streamer.emitDataRegion(MCDR_DataRegion);30 for (const ConstantPoolEntry &Entry : Entries) {31 Streamer.emitValueToAlignment(Align(Entry.Size)); // align naturally32 Streamer.emitLabel(Entry.Label);33 Streamer.emitValue(Entry.Value, Entry.Size, Entry.Loc);34 }35 Streamer.emitDataRegion(MCDR_DataRegionEnd);36 Entries.clear();37}38 39const MCExpr *ConstantPool::addEntry(const MCExpr *Value, MCContext &Context,40 unsigned Size, SMLoc Loc) {41 const MCConstantExpr *C = dyn_cast<MCConstantExpr>(Value);42 const MCSymbolRefExpr *S = dyn_cast<MCSymbolRefExpr>(Value);43 44 // Check if there is existing entry for the same constant. If so, reuse it.45 if (C) {46 auto CItr = CachedConstantEntries.find(std::make_pair(C->getValue(), Size));47 if (CItr != CachedConstantEntries.end())48 return CItr->second;49 }50 51 // Check if there is existing entry for the same symbol. If so, reuse it.52 if (S) {53 auto SItr =54 CachedSymbolEntries.find(std::make_pair(&(S->getSymbol()), Size));55 if (SItr != CachedSymbolEntries.end())56 return SItr->second;57 }58 59 MCSymbol *CPEntryLabel = Context.createTempSymbol();60 61 Entries.push_back(ConstantPoolEntry(CPEntryLabel, Value, Size, Loc));62 const auto SymRef = MCSymbolRefExpr::create(CPEntryLabel, Context, Loc);63 if (C)64 CachedConstantEntries[std::make_pair(C->getValue(), Size)] = SymRef;65 if (S)66 CachedSymbolEntries[std::make_pair(&(S->getSymbol()), Size)] = SymRef;67 return SymRef;68}69 70bool ConstantPool::empty() { return Entries.empty(); }71 72void ConstantPool::clearCache() {73 CachedConstantEntries.clear();74 CachedSymbolEntries.clear();75}76 77//78// AssemblerConstantPools implementation79//80ConstantPool *AssemblerConstantPools::getConstantPool(MCSection *Section) {81 ConstantPoolMapTy::iterator CP = ConstantPools.find(Section);82 if (CP == ConstantPools.end())83 return nullptr;84 85 return &CP->second;86}87 88ConstantPool &89AssemblerConstantPools::getOrCreateConstantPool(MCSection *Section) {90 return ConstantPools[Section];91}92 93static void emitConstantPool(MCStreamer &Streamer, MCSection *Section,94 ConstantPool &CP) {95 if (!CP.empty()) {96 Streamer.switchSection(Section);97 CP.emitEntries(Streamer);98 }99}100 101void AssemblerConstantPools::emitAll(MCStreamer &Streamer) {102 // Dump contents of assembler constant pools.103 for (auto &CPI : ConstantPools) {104 MCSection *Section = CPI.first;105 ConstantPool &CP = CPI.second;106 107 emitConstantPool(Streamer, Section, CP);108 }109}110 111void AssemblerConstantPools::emitForCurrentSection(MCStreamer &Streamer) {112 MCSection *Section = Streamer.getCurrentSectionOnly();113 if (ConstantPool *CP = getConstantPool(Section))114 emitConstantPool(Streamer, Section, *CP);115}116 117void AssemblerConstantPools::clearCacheForCurrentSection(MCStreamer &Streamer) {118 MCSection *Section = Streamer.getCurrentSectionOnly();119 if (ConstantPool *CP = getConstantPool(Section))120 CP->clearCache();121}122 123const MCExpr *AssemblerConstantPools::addEntry(MCStreamer &Streamer,124 const MCExpr *Expr,125 unsigned Size, SMLoc Loc) {126 MCSection *Section = Streamer.getCurrentSectionOnly();127 return getOrCreateConstantPool(Section).addEntry(Expr, Streamer.getContext(),128 Size, Loc);129}130