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
getPCMState(llvm::StringRef Filename) const15 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 &
addPCM(llvm::StringRef Filename,std::unique_ptr<llvm::MemoryBuffer> Buffer)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 &
addBuiltPCM(llvm::StringRef Filename,std::unique_ptr<llvm::MemoryBuffer> Buffer)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 *
lookupPCM(llvm::StringRef Filename) const44 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 
isPCMFinal(llvm::StringRef Filename) const51 bool InMemoryModuleCache::isPCMFinal(llvm::StringRef Filename) const {
52   return getPCMState(Filename) == Final;
53 }
54 
shouldBuildPCM(llvm::StringRef Filename) const55 bool InMemoryModuleCache::shouldBuildPCM(llvm::StringRef Filename) const {
56   return getPCMState(Filename) == ToBuild;
57 }
58 
tryToDropPCM(llvm::StringRef Filename)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 
finalizePCM(llvm::StringRef Filename)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 }
81