1 files changed, 219 insertions, 0 deletions
diff --git a/contrib/llvm-project/clang/lib/Frontend/ChainedIncludesSource.cpp b/contrib/llvm-project/clang/lib/Frontend/ChainedIncludesSource.cpp
new file mode 100644
index 000000000000..380eba4562b4
--- /dev/null
+++ b/contrib/llvm-project/clang/lib/Frontend/ChainedIncludesSource.cpp
@@ -0,0 +1,219 @@
+//===- ChainedIncludesSource.cpp - Chained PCHs in Memory -------*- C++ -*-===//
+//
+// 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 defines the ChainedIncludesSource class, which converts headers
+//  to chained PCHs in memory, mainly used for testing.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Basic/Builtins.h"
+#include "clang/Basic/TargetInfo.h"
+#include "clang/Frontend/ASTUnit.h"
+#include "clang/Frontend/CompilerInstance.h"
+#include "clang/Frontend/TextDiagnosticPrinter.h"
+#include "clang/Lex/Preprocessor.h"
+#include "clang/Lex/PreprocessorOptions.h"
+#include "clang/Parse/ParseAST.h"
+#include "clang/Sema/MultiplexExternalSemaSource.h"
+#include "clang/Serialization/ASTReader.h"
+#include "clang/Serialization/ASTWriter.h"
+#include "llvm/Support/MemoryBuffer.h"
+
+using namespace clang;
+
+namespace {
+class ChainedIncludesSourceImpl : public ExternalSemaSource {
+public:
+  ChainedIncludesSourceImpl(std::vector<std::unique_ptr<CompilerInstance>> CIs)
+      : CIs(std::move(CIs)) {}
+
+protected:
+  //===----------------------------------------------------------------------===//
+  // ExternalASTSource interface.
+  //===----------------------------------------------------------------------===//
+
+  /// Return the amount of memory used by memory buffers, breaking down
+  /// by heap-backed versus mmap'ed memory.
+  void getMemoryBufferSizes(MemoryBufferSizes &sizes) const override {
+    for (unsigned i = 0, e = CIs.size(); i != e; ++i) {
+      if (const ExternalASTSource *eSrc =
+          CIs[i]->getASTContext().getExternalSource()) {
+        eSrc->getMemoryBufferSizes(sizes);
+      }
+    }
+  }
+
+private:
+  std::vector<std::unique_ptr<CompilerInstance>> CIs;
+};
+
+/// Members of ChainedIncludesSource, factored out so we can initialize
+/// them before we initialize the ExternalSemaSource base class.
+struct ChainedIncludesSourceMembers {
+  ChainedIncludesSourceMembers(
+      std::vector<std::unique_ptr<CompilerInstance>> CIs,
+      IntrusiveRefCntPtr<ExternalSemaSource> FinalReader)
+      : Impl(std::move(CIs)), FinalReader(std::move(FinalReader)) {}
+  ChainedIncludesSourceImpl Impl;
+  IntrusiveRefCntPtr<ExternalSemaSource> FinalReader;
+};
+
+/// Use MultiplexExternalSemaSource to dispatch all ExternalSemaSource
+/// calls to the final reader.
+class ChainedIncludesSource
+    : private ChainedIncludesSourceMembers,
+      public MultiplexExternalSemaSource {
+public:
+  ChainedIncludesSource(std::vector<std::unique_ptr<CompilerInstance>> CIs,
+                        IntrusiveRefCntPtr<ExternalSemaSource> FinalReader)
+      : ChainedIncludesSourceMembers(std::move(CIs), std::move(FinalReader)),
+        MultiplexExternalSemaSource(Impl, *this->FinalReader) {}
+};
+}
+
+static ASTReader *
+createASTReader(CompilerInstance &CI, StringRef pchFile,
+                SmallVectorImpl<std::unique_ptr<llvm::MemoryBuffer>> &MemBufs,
+                SmallVectorImpl<std::string> &bufNames,
+                ASTDeserializationListener *deserialListener = nullptr) {
+  Preprocessor &PP = CI.getPreprocessor();
+  std::unique_ptr<ASTReader> Reader;
+  Reader.reset(new ASTReader(
+      PP, CI.getModuleCache(), &CI.getASTContext(), CI.getPCHContainerReader(),
+      /*Extensions=*/{},
+      /*isysroot=*/"", DisableValidationForModuleKind::PCH));
+  for (unsigned ti = 0; ti < bufNames.size(); ++ti) {
+    StringRef sr(bufNames[ti]);
+    Reader->addInMemoryBuffer(sr, std::move(MemBufs[ti]));
+  }
+  Reader->setDeserializationListener(deserialListener);
+  switch (Reader->ReadAST(pchFile, serialization::MK_PCH, SourceLocation(),
+                          ASTReader::ARR_None)) {
+  case ASTReader::Success:
+    // Set the predefines buffer as suggested by the PCH reader.
+    PP.setPredefines(Reader->getSuggestedPredefines());
+    return Reader.release();
+
+  case ASTReader::Failure:
+  case ASTReader::Missing:
+  case ASTReader::OutOfDate:
+  case ASTReader::VersionMismatch:
+  case ASTReader::ConfigurationMismatch:
+  case ASTReader::HadErrors:
+    break;
+  }
+  return nullptr;
+}
+
+IntrusiveRefCntPtr<ExternalSemaSource> clang::createChainedIncludesSource(
+    CompilerInstance &CI, IntrusiveRefCntPtr<ExternalSemaSource> &Reader) {
+
+  std::vector<std::string> &includes = CI.getPreprocessorOpts().ChainedIncludes;
+  assert(!includes.empty() && "No '-chain-include' in options!");
+
+  std::vector<std::unique_ptr<CompilerInstance>> CIs;
+  InputKind IK = CI.getFrontendOpts().Inputs[0].getKind();
+
+  SmallVector<std::unique_ptr<llvm::MemoryBuffer>, 4> SerialBufs;
+  SmallVector<std::string, 4> serialBufNames;
+
+  for (unsigned i = 0, e = includes.size(); i != e; ++i) {
+    bool firstInclude = (i == 0);
+    std::unique_ptr<CompilerInvocation> CInvok;
+    CInvok.reset(new CompilerInvocation(CI.getInvocation()));
+
+    CInvok->getPreprocessorOpts().ChainedIncludes.clear();
+    CInvok->getPreprocessorOpts().ImplicitPCHInclude.clear();
+    CInvok->getPreprocessorOpts().DisablePCHOrModuleValidation =
+        DisableValidationForModuleKind::PCH;
+    CInvok->getPreprocessorOpts().Includes.clear();
+    CInvok->getPreprocessorOpts().MacroIncludes.clear();
+    CInvok->getPreprocessorOpts().Macros.clear();
+
+    CInvok->getFrontendOpts().Inputs.clear();
+    FrontendInputFile InputFile(includes[i], IK);
+    CInvok->getFrontendOpts().Inputs.push_back(InputFile);
+
+    TextDiagnosticPrinter *DiagClient =
+      new TextDiagnosticPrinter(llvm::errs(), new DiagnosticOptions());
+    IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
+    IntrusiveRefCntPtr<DiagnosticsEngine> Diags(
+        new DiagnosticsEngine(DiagID, &CI.getDiagnosticOpts(), DiagClient));
+
+    std::unique_ptr<CompilerInstance> Clang(
+        new CompilerInstance(CI.getPCHContainerOperations()));
+    Clang->setInvocation(std::move(CInvok));
+    Clang->setDiagnostics(Diags.get());
+    Clang->setTarget(TargetInfo::CreateTargetInfo(
+        Clang->getDiagnostics(), Clang->getInvocation().TargetOpts));
+    Clang->createFileManager();
+    Clang->createSourceManager(Clang->getFileManager());
+    Clang->createPreprocessor(TU_Prefix);
+    Clang->getDiagnosticClient().BeginSourceFile(Clang->getLangOpts(),
+                                                 &Clang->getPreprocessor());
+    Clang->createASTContext();
+
+    auto Buffer = std::make_shared<PCHBuffer>();
+    ArrayRef<std::shared_ptr<ModuleFileExtension>> Extensions;
+    auto consumer = std::make_unique<PCHGenerator>(
+        Clang->getPreprocessor(), Clang->getModuleCache(), "-", /*isysroot=*/"",
+        Buffer, Extensions, /*AllowASTWithErrors=*/true);
+    Clang->getASTContext().setASTMutationListener(
+                                            consumer->GetASTMutationListener());
+    Clang->setASTConsumer(std::move(consumer));
+    Clang->createSema(TU_Prefix, nullptr);
+
+    if (firstInclude) {
+      Preprocessor &PP = Clang->getPreprocessor();
+      PP.getBuiltinInfo().initializeBuiltins(PP.getIdentifierTable(),
+                                             PP.getLangOpts());
+    } else {
+      assert(!SerialBufs.empty());
+      SmallVector<std::unique_ptr<llvm::MemoryBuffer>, 4> Bufs;
+      // TODO: Pass through the existing MemoryBuffer instances instead of
+      // allocating new ones.
+      for (auto &SB : SerialBufs)
+        Bufs.push_back(llvm::MemoryBuffer::getMemBuffer(SB->getBuffer()));
+      std::string pchName = includes[i-1];
+      llvm::raw_string_ostream os(pchName);
+      os << ".pch" << i-1;
+      serialBufNames.push_back(os.str());
+
+      IntrusiveRefCntPtr<ASTReader> Reader;
+      Reader = createASTReader(
+          *Clang, pchName, Bufs, serialBufNames,
+          Clang->getASTConsumer().GetASTDeserializationListener());
+      if (!Reader)
+        return nullptr;
+      Clang->setASTReader(Reader);
+      Clang->getASTContext().setExternalSource(Reader);
+    }
+
+    if (!Clang->InitializeSourceManager(InputFile))
+      return nullptr;
+
+    ParseAST(Clang->getSema());
+    Clang->getDiagnosticClient().EndSourceFile();
+    assert(Buffer->IsComplete && "serialization did not complete");
+    auto &serialAST = Buffer->Data;
+    SerialBufs.push_back(llvm::MemoryBuffer::getMemBufferCopy(
+        StringRef(serialAST.data(), serialAST.size())));
+    serialAST.clear();
+    CIs.push_back(std::move(Clang));
+  }
+
+  assert(!SerialBufs.empty());
+  std::string pchName = includes.back() + ".pch-final";
+  serialBufNames.push_back(pchName);
+  Reader = createASTReader(CI, pchName, SerialBufs, serialBufNames);
+  if (!Reader)
+    return nullptr;
+
+  return IntrusiveRefCntPtr<ChainedIncludesSource>(
+      new ChainedIncludesSource(std::move(CIs), Reader));
+}