forked from OSchip/llvm-project
				
			
		
			
				
	
	
		
			116 lines
		
	
	
		
			3.7 KiB
		
	
	
	
		
			C++
		
	
	
	
			
		
		
	
	
			116 lines
		
	
	
		
			3.7 KiB
		
	
	
	
		
			C++
		
	
	
	
//===- ConstantPools.cpp - ConstantPool class -----------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements the ConstantPool and  AssemblerConstantPools classes.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/MC/ConstantPools.h"
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#include "llvm/MC/MCContext.h"
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#include "llvm/MC/MCDirectives.h"
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#include "llvm/MC/MCExpr.h"
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#include "llvm/MC/MCStreamer.h"
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#include "llvm/Support/Casting.h"
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using namespace llvm;
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//
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// ConstantPool implementation
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//
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// Emit the contents of the constant pool using the provided streamer.
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void ConstantPool::emitEntries(MCStreamer &Streamer) {
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  if (Entries.empty())
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    return;
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  Streamer.emitDataRegion(MCDR_DataRegion);
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  for (const ConstantPoolEntry &Entry : Entries) {
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    Streamer.emitCodeAlignment(Entry.Size); // align naturally
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    Streamer.emitLabel(Entry.Label);
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    Streamer.emitValue(Entry.Value, Entry.Size, Entry.Loc);
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  }
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  Streamer.emitDataRegion(MCDR_DataRegionEnd);
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  Entries.clear();
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}
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const MCExpr *ConstantPool::addEntry(const MCExpr *Value, MCContext &Context,
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                                     unsigned Size, SMLoc Loc) {
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  const MCConstantExpr *C = dyn_cast<MCConstantExpr>(Value);
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  // Check if there is existing entry for the same constant. If so, reuse it.
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  auto Itr = C ? CachedEntries.find(C->getValue()) : CachedEntries.end();
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  if (Itr != CachedEntries.end())
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    return Itr->second;
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  MCSymbol *CPEntryLabel = Context.createTempSymbol();
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  Entries.push_back(ConstantPoolEntry(CPEntryLabel, Value, Size, Loc));
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  const auto SymRef = MCSymbolRefExpr::create(CPEntryLabel, Context);
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  if (C)
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    CachedEntries[C->getValue()] = SymRef;
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  return SymRef;
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}
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bool ConstantPool::empty() { return Entries.empty(); }
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void ConstantPool::clearCache() {
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  CachedEntries.clear();
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}
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//
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// AssemblerConstantPools implementation
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//
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ConstantPool *AssemblerConstantPools::getConstantPool(MCSection *Section) {
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  ConstantPoolMapTy::iterator CP = ConstantPools.find(Section);
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  if (CP == ConstantPools.end())
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    return nullptr;
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  return &CP->second;
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}
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ConstantPool &
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AssemblerConstantPools::getOrCreateConstantPool(MCSection *Section) {
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  return ConstantPools[Section];
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}
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static void emitConstantPool(MCStreamer &Streamer, MCSection *Section,
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                             ConstantPool &CP) {
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  if (!CP.empty()) {
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    Streamer.SwitchSection(Section);
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    CP.emitEntries(Streamer);
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  }
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}
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void AssemblerConstantPools::emitAll(MCStreamer &Streamer) {
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  // Dump contents of assembler constant pools.
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  for (auto &CPI : ConstantPools) {
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    MCSection *Section = CPI.first;
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    ConstantPool &CP = CPI.second;
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    emitConstantPool(Streamer, Section, CP);
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  }
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}
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void AssemblerConstantPools::emitForCurrentSection(MCStreamer &Streamer) {
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  MCSection *Section = Streamer.getCurrentSectionOnly();
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  if (ConstantPool *CP = getConstantPool(Section))
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    emitConstantPool(Streamer, Section, *CP);
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}
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void AssemblerConstantPools::clearCacheForCurrentSection(MCStreamer &Streamer) {
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  MCSection *Section = Streamer.getCurrentSectionOnly();
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  if (ConstantPool *CP = getConstantPool(Section))
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    CP->clearCache();
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}
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const MCExpr *AssemblerConstantPools::addEntry(MCStreamer &Streamer,
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                                               const MCExpr *Expr,
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                                               unsigned Size, SMLoc Loc) {
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  MCSection *Section = Streamer.getCurrentSectionOnly();
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  return getOrCreateConstantPool(Section).addEntry(Expr, Streamer.getContext(),
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                                                   Size, Loc);
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}
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