clang/lib/Serialization/InMemoryModuleCache.cpp

   1 //===- InMemoryModuleCache.cpp - Cache for loaded memory buffers ----------===//
   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-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "clang/Serialization/InMemoryModuleCache.h"
  10 #include "llvm/Support/MemoryBuffer.h"
  11
  12 using namespace clang;
  13
  14 InMemoryModuleCache::State
  15 InMemoryModuleCache::getPCMState(llvm::StringRef Filename) const {
  16   auto I = PCMs.find(Filename);
  17   if (I == PCMs.end())
  18     return Unknown;
  19   if (I->second.IsFinal)
  20     return Final;
  21   return I->second.Buffer ? Tentative : ToBuild;
  22 }
  23
  24 llvm::MemoryBuffer &
  25 InMemoryModuleCache::addPCM(llvm::StringRef Filename,
  26                             std::unique_ptr<llvm::MemoryBuffer> Buffer) {
  27   auto Insertion = PCMs.insert(std::make_pair(Filename, std::move(Buffer)));
  28   assert(Insertion.second && "Already has a PCM");
  29   return *Insertion.first->second.Buffer;
  30 }
  31
  32 llvm::MemoryBuffer &
  33 InMemoryModuleCache::addBuiltPCM(llvm::StringRef Filename,
  34                                  std::unique_ptr<llvm::MemoryBuffer> Buffer) {
  35   auto &PCM = PCMs[Filename];
  36   assert(!PCM.IsFinal && "Trying to override finalized PCM?");
  37   assert(!PCM.Buffer && "Trying to override tentative PCM?");
  38   PCM.Buffer = std::move(Buffer);
  39   PCM.IsFinal = true;
  40   return *PCM.Buffer;
  41 }
  42
  43 llvm::MemoryBuffer *
  44 InMemoryModuleCache::lookupPCM(llvm::StringRef Filename) const {
  45   auto I = PCMs.find(Filename);
  46   if (I == PCMs.end())
  47     return nullptr;
  48   return I->second.Buffer.get();
  49 }
  50
  51 bool InMemoryModuleCache::isPCMFinal(llvm::StringRef Filename) const {
  52   return getPCMState(Filename) == Final;
  53 }
  54
  55 bool InMemoryModuleCache::shouldBuildPCM(llvm::StringRef Filename) const {
  56   return getPCMState(Filename) == ToBuild;
  57 }
  58
  59 bool InMemoryModuleCache::tryToDropPCM(llvm::StringRef Filename) {
  60   auto I = PCMs.find(Filename);
  61   assert(I != PCMs.end() && "PCM to remove is unknown...");
  62
  63   auto &PCM = I->second;
  64   assert(PCM.Buffer && "PCM to remove is scheduled to be built...");
  65
  66   if (PCM.IsFinal)
  67     return true;
  68
  69   PCM.Buffer.reset();
  70   return false;
  71 }
  72
  73 void InMemoryModuleCache::finalizePCM(llvm::StringRef Filename) {
  74   auto I = PCMs.find(Filename);
  75   assert(I != PCMs.end() && "PCM to finalize is unknown...");
  76
  77   auto &PCM = I->second;
  78   assert(PCM.Buffer && "Trying to finalize a dropped PCM...");
  79   PCM.IsFinal = true;
  80 }