[llvm] r282299 - LTO: Simplify caching interface.

Peter Collingbourne via llvm-commits llvm-commits at lists.llvm.org
Fri Sep 23 16:32:30 PDT 2016


Should be fixed by r282313.

Peter

On Fri, Sep 23, 2016 at 4:11 PM, Zachary Turner <zturner at google.com> wrote:

> Hi Peter, I'm getting compilation failures with this.
>
> [748/3638] Building CXX object lib\LTO\CMakeFiles\LLVMLTO.
> dir\Caching.cpp.obj
> FAILED: C:\PROGRA~2\MICROS~1.0\VC\bin\AMD64_~2\cl.exe   /nologo /TP
> -DGTEST_HAS_RTTI=0 -DUNICODE -D_CRT_NONSTDC_NO_DEPRECATE
> -D_CRT_NONSTDC_NO_WARNINGS -D_CRT_SECURE_NO_DEPRECATE
> -D_CRT_SECURE_NO_WARNINGS -D_HAS_EXCEPTIONS=0 -D_SCL_SECURE_NO_DEPRECATE
> -D_SCL_SECURE_NO_WARNINGS -D_UNICODE -D__STDC_CONSTANT_MACROS
> -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -Ilib\LTO
> -ID:\src\llvm\lib\LTO -Iinclude -ID:\src\llvm\include /DWIN32 /D_WINDOWS
> /W4 -wd4141 -wd4146 -wd4180 -wd4244 -wd4258 -wd4267 -wd4291 -wd4345 -wd4351
> -wd4355 -wd4456 -wd4457 -wd4458 -wd4459 -wd4503 -wd4624 -wd4722 -wd4800
> -wd4100 -wd4127 -wd4512 -wd4505 -wd4610 -wd4510 -wd4702 -wd4245 -wd4706
> -wd4310 -wd4701 -wd4703 -wd4389 -wd4611 -wd4805 -wd4204 -wd4577 -wd4091
> -wd4592 -wd4319 -wd4324 -w14062 -we4238 /Zc:inline /Zc:strictStrings /Oi
> /Zc:rvalueCast /Zc:sizedDealloc- /D_DEBUG /MDd /Zi /Ob0 /Od /RTC1
>  /EHs-c- /GR- /showIncludes /Folib\LTO\CMakeFiles\LLVMLTO.dir\Caching.cpp.obj
> /Fdlib\LTO\CMakeFiles\LLVMLTO.dir\ /FS -c D:\src\llvm\lib\LTO\Caching.cpp
> D:\src\llvm\lib\LTO\Caching.cpp(96): error C2668: 'llvm::make_unique':
> ambiguous call to overloaded function
> D:\src\llvm\include\llvm/ADT/STLExtras.h(563): note: could be
> 'std::unique_ptr<llvm::lto::localCache::<lambda_
> 24b0b9154e270ae79e71d53f81fee0dc>::()::CacheStream,std::default_delete<_Ty>>
> llvm::make_unique<llvm::lto::localCache::<lambda_
> 24b0b9154e270ae79e71d53f81fee0dc>::()::CacheStream,std::
> unique_ptr<llvm::raw_fd_ostream,std::default_delete<llvm::raw_fd_ostream>>,const
> llvm::lto::AddFileFn&,llvm::StringRef,llvm::StringRef,
> size_t&>(std::unique_ptr<llvm::raw_fd_ostream,std::default_delete<llvm::raw_fd_ostream>>
> &&,const llvm::lto::AddFileFn &,llvm::StringRef &&,llvm::StringRef
> &&,size_t &)'
>     with
>                                                             [
>
>                                            _Ty=llvm::lto::localCache::<
> lambda_24b0b9154e270ae79e71d53f81fee0dc>::()::CacheStream
>         ]
>                                                          C:\Program Files
> (x86)\Microsoft Visual Studio 14.0\VC\INCLUDE\memory(1628): note: or
> 'std::unique_ptr<llvm::lto::localCache::<lambda_
> 24b0b9154e270ae79e71d53f81fee0dc>::()::CacheStream,std::default_delete<_Ty>>
> std::make_unique<llvm::lto::localCache::<lambda_
> 24b0b9154e270ae79e71d53f81fee0dc>::()::CacheStream,std::
> unique_ptr<llvm::raw_fd_ostream,std::default_delete<llvm::raw_fd_ostream>>,const
> llvm::lto::AddFileFn&,llvm::StringRef,llvm::StringRef,
> size_t&>(std::unique_ptr<llvm::raw_fd_ostream,std::default_delete<llvm::raw_fd_ostream>>
> &&,const llvm::lto::AddFileFn &,llvm::StringRef &&,llvm::StringRef
> &&,size_t &)' [found using argument-dependent lookup]
>
>                               with
>
>           [
>             _Ty=llvm::lto::localCache::<lambda_
> 24b0b9154e270ae79e71d53f81fee0dc>::()::CacheStream
>                    ]
>
>  D:\src\llvm\lib\LTO\Caching.cpp(96): note: while trying to match the
> argument list '(std::unique_ptr<llvm::raw_fd_ostream,std::default_delete<_Ty>>,
> const llvm::lto::AddFileFn, llvm::StringRef, llvm::StringRef, std::size_t)'
>                                              with
>
>                         [
>
>        _Ty=llvm::raw_fd_ostream
>                                                           ]
>
>                              [748/3638] Building AMDGPUGenInstrInfo.inc...
> ninja: build stopped: subcommand failed.
>
> On Fri, Sep 23, 2016 at 2:42 PM Peter Collingbourne via llvm-commits <
> llvm-commits at lists.llvm.org> wrote:
>
>> Author: pcc
>> Date: Fri Sep 23 16:33:43 2016
>> New Revision: 282299
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=282299&view=rev
>> Log:
>> LTO: Simplify caching interface.
>>
>> The NativeObjectOutput class has a design problem: it mixes up the caching
>> policy with the interface for output streams, which makes the client-side
>> code hard to follow and would for example make it harder to replace the
>> cache implementation in an arbitrary client.
>>
>> This change separates the two aspects by moving the caching policy
>> to a separate field in Config, replacing NativeObjectOutput with a
>> NativeObjectStream class which only deals with streams and does not need
>> to
>> be overridden by most clients and introducing an AddFile callback for
>> adding
>> files (e.g. from the cache) to the link.
>>
>> Differential Revision: https://reviews.llvm.org/D24622
>>
>> Modified:
>>     llvm/trunk/include/llvm/LTO/Caching.h
>>     llvm/trunk/include/llvm/LTO/Config.h
>>     llvm/trunk/include/llvm/LTO/LTO.h
>>     llvm/trunk/include/llvm/LTO/LTOBackend.h
>>     llvm/trunk/lib/LTO/Caching.cpp
>>     llvm/trunk/lib/LTO/LTO.cpp
>>     llvm/trunk/lib/LTO/LTOBackend.cpp
>>     llvm/trunk/tools/gold/gold-plugin.cpp
>>     llvm/trunk/tools/llvm-lto2/llvm-lto2.cpp
>>
>> Modified: llvm/trunk/include/llvm/LTO/Caching.h
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/
>> llvm/LTO/Caching.h?rev=282299&r1=282298&r2=282299&view=diff
>> ============================================================
>> ==================
>> --- llvm/trunk/include/llvm/LTO/Caching.h (original)
>> +++ llvm/trunk/include/llvm/LTO/Caching.h Fri Sep 23 16:33:43 2016
>> @@ -7,92 +7,29 @@
>>  //
>>  //===------------------------------------------------------
>> ----------------===//
>>  //
>> -// This file defines the lto::CacheObjectOutput data structure, which
>> allows
>> -// clients to add a filesystem cache to ThinLTO
>> +// This file defines the localCache function, which allows clients to
>> add a
>> +// filesystem cache to ThinLTO.
>>  //
>>  //===------------------------------------------------------
>> ----------------===//
>>
>>  #ifndef LLVM_LTO_CACHING_H
>>  #define LLVM_LTO_CACHING_H
>>
>> -#include "llvm/ADT/SmallString.h"
>> -#include "llvm/LTO/Config.h"
>> -#include "llvm/Support/MemoryBuffer.h"
>> +#include "llvm/LTO/LTO.h"
>> +#include <string>
>>
>>  namespace llvm {
>>  namespace lto {
>> -/// Type for client-supplied callback when a buffer is loaded from the
>> cache.
>> -typedef std::function<void(std::string)> AddBufferFn;
>>
>> -/// Manage caching on the filesystem.
>> +/// This type defines the callback to add a pre-existing native object
>> file
>> +/// (e.g. in a cache).
>>  ///
>> -/// The general scheme is the following:
>> -///
>> -/// void do_stuff(AddBufferFn CallBack) {
>> -///   /* ... */
>> -///   {
>> -///     /* Create the CacheObjectOutput pointing to a cache directory */
>> -///     auto Output = CacheObjectOutput("/tmp/cache", CallBack)
>> -///
>> -///     /* Call some processing function */
>> -///     process(Output);
>> -///
>> -///   } /* Callback is only called now, on destruction of the Output
>> object */
>> -///   /* ... */
>> -/// }
>> -///
>> -///
>> -/// void process(NativeObjectOutput &Output) {
>> -///   /* check if caching is supported */
>> -///   if (Output.isCachingEnabled()) {
>> -///     auto Key = ComputeKeyForEntry(...); // "expensive" call
>> -///     if (Output.tryLoadFromCache())
>> -///        return; // Cache hit
>> -///   }
>> -///
>> -///   auto OS = Output.getStream();
>> -///
>> -///   OS << ...;
>> -///   /* Note that the callback is not called here, but only when the
>> caller
>> -///      destroys Output */
>> -/// }
>> -///
>> -class CacheObjectOutput : public NativeObjectOutput {
>> -  /// Path to the on-disk cache directory
>> -  StringRef CacheDirectoryPath;
>> -  /// Path to this entry in the cache, initialized by tryLoadFromCache().
>> -  SmallString<128> EntryPath;
>> -  /// Path to temporary file used to buffer output that will be
>> committed to the
>> -  /// cache entry when this object is destroyed
>> -  SmallString<128> TempFilename;
>> -  /// User-supplied callback, used to provide path to cache entry
>> -  /// (potentially after creating it).
>> -  AddBufferFn AddBuffer;
>> -
>> -public:
>> -  /// The destructor pulls the entry from the cache and calls the
>> AddBuffer
>> -  /// callback, after committing the entry into the cache on miss.
>> -  ~CacheObjectOutput();
>> -
>> -  /// Create a CacheObjectOutput: the client is supposed to create it in
>> the
>> -  /// callback supplied to LTO::run. The \p CacheDirectoryPath points to
>> the
>> -  /// directory on disk where to store the cache, and \p AddBuffer will
>> be
>> -  /// called when the buffer is ready to be pulled out of the cache
>> -  /// (potentially after creating it).
>> -  CacheObjectOutput(StringRef CacheDirectoryPath, AddBufferFn AddBuffer)
>> -      : CacheDirectoryPath(CacheDirectoryPath), AddBuffer(AddBuffer) {}
>> -
>> -  /// Return an allocated stream for the output, or null in case of
>> failure.
>> -  std::unique_ptr<raw_pwrite_stream> getStream() override;
>> -
>> -  /// Set EntryPath, try loading from a possible cache first, return
>> true on
>> -  /// cache hit.
>> -  bool tryLoadFromCache(StringRef Key) override;
>> -
>> -  /// Returns true to signal that this implementation of NativeObjectFile
>> -  /// support caching.
>> -  bool isCachingEnabled() const override { return true; }
>> -};
>> +/// File callbacks must be thread safe.
>> +typedef std::function<void(unsigned Task, StringRef Path)> AddFileFn;
>> +
>> +/// Create a local file system cache which uses the given cache
>> directory and
>> +/// file callback.
>> +NativeObjectCache localCache(std::string CacheDirectoryPath, AddFileFn
>> AddFile);
>>
>>  } // namespace lto
>>  } // namespace llvm
>>
>> Modified: llvm/trunk/include/llvm/LTO/Config.h
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/
>> llvm/LTO/Config.h?rev=282299&r1=282298&r2=282299&view=diff
>> ============================================================
>> ==================
>> --- llvm/trunk/include/llvm/LTO/Config.h (original)
>> +++ llvm/trunk/include/llvm/LTO/Config.h Fri Sep 23 16:33:43 2016
>> @@ -30,38 +30,6 @@ class raw_pwrite_stream;
>>
>>  namespace lto {
>>
>> -/// Abstract class representing a single Task output to be implemented
>> by the
>> -/// client of the LTO API.
>> -///
>> -/// The general scheme the API is called is the following:
>> -///
>> -/// void process(NativeObjectOutput &Output) {
>> -///   /* check if caching is supported */
>> -///   if (Output.isCachingEnabled()) {
>> -///     auto Key = ComputeKeyForEntry(...); // "expensive" call
>> -///     if (Output.tryLoadFromCache())
>> -///        return; // Cache hit
>> -///   }
>> -///
>> -///   auto OS = Output.getStream();
>> -///
>> -///   OS << ....;
>> -/// }
>> -///
>> -class NativeObjectOutput {
>> -public:
>> -  // Return an allocated stream for the output, or null in case of
>> failure.
>> -  virtual std::unique_ptr<raw_pwrite_stream> getStream() = 0;
>> -
>> -  // Try loading from a possible cache first, return true on cache hit.
>> -  virtual bool tryLoadFromCache(StringRef Key) { return false; }
>> -
>> -  // Returns true if a cache is available
>> -  virtual bool isCachingEnabled() const { return false; }
>> -
>> -  virtual ~NativeObjectOutput() = default;
>> -};
>> -
>>  /// LTO configuration. A linker can configure LTO by setting fields in
>> this data
>>  /// structure and passing it to the lto::LTO constructor.
>>  struct Config {
>> @@ -235,13 +203,6 @@ struct Config {
>>                       bool UseInputModulePath = false);
>>  };
>>
>> -/// This type defines the callback to add a native object that is
>> generated on
>> -/// the fly.
>> -///
>> -/// Output callbacks must be thread safe.
>> -typedef std::function<std::unique_ptr<NativeObjectOutput>(unsigned
>> Task)>
>> -    AddOutputFn;
>> -
>>  /// A derived class of LLVMContext that initializes itself according to
>> a given
>>  /// Config object. The purpose of this class is to tie ownership of the
>>  /// diagnostic handler to the context, as opposed to the Config object
>> (which
>>
>> Modified: llvm/trunk/include/llvm/LTO/LTO.h
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/
>> llvm/LTO/LTO.h?rev=282299&r1=282298&r2=282299&view=diff
>> ============================================================
>> ==================
>> --- llvm/trunk/include/llvm/LTO/LTO.h (original)
>> +++ llvm/trunk/include/llvm/LTO/LTO.h Fri Sep 23 16:33:43 2016
>> @@ -247,13 +247,47 @@ public:
>>    }
>>  };
>>
>> +/// This class wraps an output stream for a native object. Most clients
>> should
>> +/// just be able to return an instance of this base class from the stream
>> +/// callback, but if a client needs to perform some action after the
>> stream is
>> +/// written to, that can be done by deriving from this class and
>> overriding the
>> +/// destructor.
>> +class NativeObjectStream {
>> +public:
>> +  NativeObjectStream(std::unique_ptr<raw_pwrite_stream> OS) :
>> OS(std::move(OS)) {}
>> +  std::unique_ptr<raw_pwrite_stream> OS;
>> +  virtual ~NativeObjectStream() = default;
>> +};
>> +
>> +/// This type defines the callback to add a native object that is
>> generated on
>> +/// the fly.
>> +///
>> +/// Stream callbacks must be thread safe.
>> +typedef std::function<std::unique_ptr<NativeObjectStream>(unsigned
>> Task)>
>> +    AddStreamFn;
>> +
>> +/// This is the type of a native object cache. To request an item from
>> the
>> +/// cache, pass a unique string as the Key. For hits, the cached file
>> will be
>> +/// added to the link and this function will return AddStreamFn(). For
>> misses,
>> +/// the cache will return a stream callback which must be called at most
>> once to
>> +/// produce content for the stream. The native object stream produced by
>> the
>> +/// stream callback will add the file to the link after the stream is
>> written
>> +/// to.
>> +///
>> +/// Clients generally look like this:
>> +///
>> +/// if (AddStreamFn AddStream = Cache(Task, Key))
>> +///   ProduceContent(AddStream);
>> +typedef std::function<AddStreamFn(unsigned Task, StringRef Key)>
>> +    NativeObjectCache;
>> +
>>  /// A ThinBackend defines what happens after the thin-link phase during
>> ThinLTO.
>>  /// The details of this type definition aren't important; clients can
>> only
>>  /// create a ThinBackend using one of the create*ThinBackend() functions
>> below.
>>  typedef std::function<std::unique_ptr<ThinBackendProc>(
>>      Config &C, ModuleSummaryIndex &CombinedIndex,
>>      StringMap<GVSummaryMapTy> &ModuleToDefinedGVSummaries,
>> -    AddOutputFn AddOutput)>
>> +    AddStreamFn AddStream, NativeObjectCache Cache)>
>>      ThinBackend;
>>
>>  /// This ThinBackend runs the individual backend jobs in-process.
>> @@ -286,8 +320,9 @@ ThinBackend createWriteIndexesThinBacken
>>  ///   and pass it and an array of symbol resolutions to the add()
>> function.
>>  /// - Call the getMaxTasks() function to get an upper bound on the
>> number of
>>  ///   native object files that LTO may add to the link.
>> -/// - Call the run() function. This function will use the supplied
>> AddOutput
>> -///   function to add up to getMaxTasks() native object files to the
>> link.
>> +/// - Call the run() function. This function will use the supplied
>> AddStream
>> +///   and Cache functions to add up to getMaxTasks() native object files
>> to
>> +///   the link.
>>  class LTO {
>>    friend InputFile;
>>
>> @@ -310,9 +345,15 @@ public:
>>    /// full description of tasks see LTOBackend.h.
>>    unsigned getMaxTasks() const;
>>
>> -  /// Runs the LTO pipeline. This function calls the supplied AddOutput
>> function
>> -  /// to add native object files to the link.
>> -  Error run(AddOutputFn AddOutput);
>> +  /// Runs the LTO pipeline. This function calls the supplied AddStream
>> +  /// function to add native object files to the link.
>> +  ///
>> +  /// The Cache parameter is optional. If supplied, it will be used to
>> cache
>> +  /// native object files and add them to the link.
>> +  ///
>> +  /// The client will receive at most one callback (via either AddStream
>> or
>> +  /// Cache) for each task identifier.
>> +  Error run(AddStreamFn AddStream, NativeObjectCache Cache = nullptr);
>>
>>  private:
>>    Config Conf;
>> @@ -393,8 +434,9 @@ private:
>>    Error addThinLTO(std::unique_ptr<InputFile> Input,
>>                     ArrayRef<SymbolResolution> Res);
>>
>> -  Error runRegularLTO(AddOutputFn AddOutput);
>> -  Error runThinLTO(AddOutputFn AddOutput, bool HasRegularLTO);
>> +  Error runRegularLTO(AddStreamFn AddStream);
>> +  Error runThinLTO(AddStreamFn AddStream, NativeObjectCache Cache,
>> +                   bool HasRegularLTO);
>>
>>    mutable bool CalledGetMaxTasks = false;
>>  };
>>
>> Modified: llvm/trunk/include/llvm/LTO/LTOBackend.h
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/
>> llvm/LTO/LTOBackend.h?rev=282299&r1=282298&r2=282299&view=diff
>> ============================================================
>> ==================
>> --- llvm/trunk/include/llvm/LTO/LTOBackend.h (original)
>> +++ llvm/trunk/include/llvm/LTO/LTOBackend.h Fri Sep 23 16:33:43 2016
>> @@ -20,7 +20,7 @@
>>  #include "llvm/ADT/MapVector.h"
>>  #include "llvm/IR/DiagnosticInfo.h"
>>  #include "llvm/IR/ModuleSummaryIndex.h"
>> -#include "llvm/LTO/Config.h"
>> +#include "llvm/LTO/LTO.h"
>>  #include "llvm/Support/MemoryBuffer.h"
>>  #include "llvm/Target/TargetOptions.h"
>>  #include "llvm/Transforms/IPO/FunctionImport.h"
>> @@ -34,12 +34,12 @@ class Target;
>>  namespace lto {
>>
>>  /// Runs a regular LTO backend.
>> -Error backend(Config &C, AddOutputFn AddStream,
>> +Error backend(Config &C, AddStreamFn AddStream,
>>                unsigned ParallelCodeGenParallelismLevel,
>>                std::unique_ptr<Module> M);
>>
>>  /// Runs a ThinLTO backend.
>> -Error thinBackend(Config &C, unsigned Task, AddOutputFn AddStream,
>> Module &M,
>> +Error thinBackend(Config &C, unsigned Task, AddStreamFn AddStream,
>> Module &M,
>>                    ModuleSummaryIndex &CombinedIndex,
>>                    const FunctionImporter::ImportMapTy &ImportList,
>>                    const GVSummaryMapTy &DefinedGlobals,
>>
>> Modified: llvm/trunk/lib/LTO/Caching.cpp
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/LTO/
>> Caching.cpp?rev=282299&r1=282298&r2=282299&view=diff
>> ============================================================
>> ==================
>> --- llvm/trunk/lib/LTO/Caching.cpp (original)
>> +++ llvm/trunk/lib/LTO/Caching.cpp Fri Sep 23 16:33:43 2016
>> @@ -12,13 +12,9 @@
>>  //===------------------------------------------------------
>> ----------------===//
>>
>>  #include "llvm/LTO/Caching.h"
>> -
>> -#ifdef HAVE_LLVM_REVISION
>> -#include "LLVMLTORevision.h"
>> -#endif
>> -
>>  #include "llvm/ADT/StringExtras.h"
>>  #include "llvm/Support/FileSystem.h"
>> +#include "llvm/Support/MemoryBuffer.h"
>>  #include "llvm/Support/Path.h"
>>  #include "llvm/Support/raw_ostream.h"
>>
>> @@ -30,6 +26,8 @@ static void commitEntry(StringRef TempFi
>>    auto EC = sys::fs::rename(TempFilename, EntryPath);
>>    if (EC) {
>>      // Renaming failed, probably not the same filesystem, copy and
>> delete.
>> +    // FIXME: Avoid needing to do this by creating the temporary file in
>> the
>> +    // cache directory.
>>      {
>>        auto ReloadedBufferOrErr = MemoryBuffer::getFile(TempFilename);
>>        if (auto EC = ReloadedBufferOrErr.getError())
>> @@ -48,51 +46,54 @@ static void commitEntry(StringRef TempFi
>>    }
>>  }
>>
>> -CacheObjectOutput::~CacheObjectOutput() {
>> -  if (EntryPath.empty())
>> -    // The entry was never used by the client (tryLoadFromCache() wasn't
>> called)
>> -    return;
>> -  // TempFilename is only set if getStream() was called, i.e. on cache
>> miss when
>> -  // tryLoadFromCache() returned false. And EntryPath is valid if a Key
>> was
>> -  // submitted, otherwise it has been set to CacheDirectoryPath in
>> -  // tryLoadFromCache.
>> -  if (!TempFilename.empty()) {
>> -    if (EntryPath == CacheDirectoryPath)
>> -      // The Key supplied to tryLoadFromCache was empty, do not commit
>> the temp.
>> -      EntryPath = TempFilename;
>> -    else
>> -      // We commit the tempfile into the cache now, by moving it to
>> EntryPath.
>> -      commitEntry(TempFilename, EntryPath);
>> -  }
>> -  // Supply the cache path to the user.
>> -  AddBuffer(EntryPath.str());
>> -}
>> -
>> -// Return an allocated stream for the output, or null in case of failure.
>> -std::unique_ptr<raw_pwrite_stream> CacheObjectOutput::getStream() {
>> -  assert(!EntryPath.empty() && "API Violation: client didn't call "
>> -                               "tryLoadFromCache() before getStream()");
>> -  // Write to a temporary to avoid race condition
>> -  int TempFD;
>> -  std::error_code EC =
>> -      sys::fs::createTemporaryFile("Thin", "tmp.o", TempFD,
>> TempFilename);
>> -  if (EC) {
>> -    errs() << "Error: " << EC.message() << "\n";
>> -    report_fatal_error("ThinLTO: Can't get a temporary file");
>> -  }
>> -  return llvm::make_unique<raw_fd_ostream>(TempFD, /* ShouldClose */
>> true);
>> -}
>> +NativeObjectCache lto::localCache(std::string CacheDirectoryPath,
>> +                                  AddFileFn AddFile) {
>> +  return [=](unsigned Task, StringRef Key) -> AddStreamFn {
>> +    // First, see if we have a cache hit.
>> +    SmallString<64> EntryPath;
>> +    sys::path::append(EntryPath, CacheDirectoryPath, Key);
>> +    if (sys::fs::exists(EntryPath)) {
>> +      AddFile(Task, EntryPath);
>> +      return AddStreamFn();
>> +    }
>>
>> -// Try loading from a possible cache first, return true on cache hit.
>> -bool CacheObjectOutput::tryLoadFromCache(StringRef Key) {
>> -  assert(!CacheDirectoryPath.empty() &&
>> -         "CacheObjectOutput was initialized without a cache path");
>> -  if (Key.empty()) {
>> -    // Client didn't compute a valid key. EntryPath has been set to
>> -    // CacheDirectoryPath.
>> -    EntryPath = CacheDirectoryPath;
>> -    return false;
>> -  }
>> -  sys::path::append(EntryPath, CacheDirectoryPath, Key);
>> -  return sys::fs::exists(EntryPath);
>> +    // This native object stream is responsible for commiting the
>> resulting
>> +    // file to the cache and calling AddFile to add it to the link.
>> +    struct CacheStream : NativeObjectStream {
>> +      AddFileFn AddFile;
>> +      std::string TempFilename;
>> +      std::string EntryPath;
>> +      unsigned Task;
>> +
>> +      CacheStream(std::unique_ptr<raw_pwrite_stream> OS, AddFileFn
>> AddFile,
>> +                  std::string TempFilename, std::string EntryPath,
>> +                  unsigned Task)
>> +          : NativeObjectStream(std::move(OS)), AddFile(AddFile),
>> +            TempFilename(TempFilename), EntryPath(EntryPath), Task(Task)
>> {}
>> +
>> +      ~CacheStream() {
>> +        // Make sure the file is closed before committing it.
>> +        OS.reset();
>> +        commitEntry(TempFilename, EntryPath);
>> +        AddFile(Task, EntryPath);
>> +      }
>> +    };
>> +
>> +    return [=](size_t Task) -> std::unique_ptr<NativeObjectStream> {
>> +      // Write to a temporary to avoid race condition
>> +      int TempFD;
>> +      SmallString<64> TempFilename;
>> +      std::error_code EC =
>> +          sys::fs::createTemporaryFile("Thin", "tmp.o", TempFD,
>> TempFilename);
>> +      if (EC) {
>> +        errs() << "Error: " << EC.message() << "\n";
>> +        report_fatal_error("ThinLTO: Can't get a temporary file");
>> +      }
>> +
>> +      // This CacheStream will move the temporary file into the cache
>> when done.
>> +      return make_unique<CacheStream>(
>> +          llvm::make_unique<raw_fd_ostream>(TempFD, /* ShouldClose */
>> true),
>> +          AddFile, TempFilename.str(), EntryPath.str(), Task);
>> +    };
>> +  };
>>  }
>>
>> Modified: llvm/trunk/lib/LTO/LTO.cpp
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/LTO/
>> LTO.cpp?rev=282299&r1=282298&r2=282299&view=diff
>> ============================================================
>> ==================
>> --- llvm/trunk/lib/LTO/LTO.cpp (original)
>> +++ llvm/trunk/lib/LTO/LTO.cpp Fri Sep 23 16:33:43 2016
>> @@ -409,19 +409,19 @@ unsigned LTO::getMaxTasks() const {
>>    return RegularLTO.ParallelCodeGenParallelismLevel +
>> ThinLTO.ModuleMap.size();
>>  }
>>
>> -Error LTO::run(AddOutputFn AddOutput) {
>> +Error LTO::run(AddStreamFn AddStream, NativeObjectCache Cache) {
>>    // Save the status of having a regularLTO combined module, as
>>    // this is needed for generating the ThinLTO Task ID, and
>>    // the CombinedModule will be moved at the end of runRegularLTO.
>>    bool HasRegularLTO = RegularLTO.CombinedModule != nullptr;
>>    // Invoke regular LTO if there was a regular LTO module to start with.
>>    if (HasRegularLTO)
>> -    if (auto E = runRegularLTO(AddOutput))
>> +    if (auto E = runRegularLTO(AddStream))
>>        return E;
>> -  return runThinLTO(AddOutput, HasRegularLTO);
>> +  return runThinLTO(AddStream, Cache, HasRegularLTO);
>>  }
>>
>> -Error LTO::runRegularLTO(AddOutputFn AddOutput) {
>> +Error LTO::runRegularLTO(AddStreamFn AddStream) {
>>    // Make sure commons have the right size/alignment: we kept the
>> largest from
>>    // all the prevailing when adding the inputs, and we apply it here.
>>    const DataLayout &DL = RegularLTO.CombinedModule->getDataLayout();
>> @@ -478,7 +478,7 @@ Error LTO::runRegularLTO(AddOutputFn Add
>>          !Conf.PostInternalizeModuleHook(0, *RegularLTO.CombinedModule))
>>        return Error();
>>    }
>> -  return backend(Conf, AddOutput, RegularLTO.
>> ParallelCodeGenParallelismLevel,
>> +  return backend(Conf, AddStream, RegularLTO.
>> ParallelCodeGenParallelismLevel,
>>                   std::move(RegularLTO.CombinedModule));
>>  }
>>
>> @@ -507,7 +507,8 @@ public:
>>
>>  class InProcessThinBackend : public ThinBackendProc {
>>    ThreadPool BackendThreadPool;
>> -  AddOutputFn AddOutput;
>> +  AddStreamFn AddStream;
>> +  NativeObjectCache Cache;
>>
>>    Optional<Error> Err;
>>    std::mutex ErrMu;
>> @@ -517,42 +518,40 @@ public:
>>        Config &Conf, ModuleSummaryIndex &CombinedIndex,
>>        unsigned ThinLTOParallelismLevel,
>>        const StringMap<GVSummaryMapTy> &ModuleToDefinedGVSummaries,
>> -      AddOutputFn AddOutput)
>> +      AddStreamFn AddStream, NativeObjectCache Cache)
>>        : ThinBackendProc(Conf, CombinedIndex, ModuleToDefinedGVSummaries),
>>          BackendThreadPool(ThinLTOParallelismLevel),
>> -        AddOutput(std::move(AddOutput)) {}
>> +        AddStream(std::move(AddStream)), Cache(std::move(Cache)) {}
>>
>>    Error runThinLTOBackendThread(
>> -      AddOutputFn AddOutput, unsigned Task, MemoryBufferRef MBRef,
>> -      ModuleSummaryIndex &CombinedIndex,
>> +      AddStreamFn AddStream, NativeObjectCache Cache, unsigned Task,
>> +      MemoryBufferRef MBRef, ModuleSummaryIndex &CombinedIndex,
>>        const FunctionImporter::ImportMapTy &ImportList,
>>        const FunctionImporter::ExportSetTy &ExportList,
>>        const std::map<GlobalValue::GUID, GlobalValue::LinkageTypes>
>> &ResolvedODR,
>>        const GVSummaryMapTy &DefinedGlobals,
>>        MapVector<StringRef, MemoryBufferRef> &ModuleMap) {
>> +    auto RunThinBackend = [&](AddStreamFn AddStream) {
>> +      LTOLLVMContext BackendContext(Conf);
>> +      ErrorOr<std::unique_ptr<Module>> MOrErr =
>> +          parseBitcodeFile(MBRef, BackendContext);
>> +      assert(MOrErr && "Unable to load module in thread?");
>>
>> -    auto ModuleIdentifier = MBRef.getBufferIdentifier();
>> -    auto Output = AddOutput(Task);
>> -    if (Output->isCachingEnabled()) {
>> -      SmallString<40> Key;
>> -      // The module may be cached, this helps handling it.
>> -      computeCacheKey(Key, CombinedIndex, ModuleIdentifier, ImportList,
>> -                      ExportList, ResolvedODR, DefinedGlobals);
>> -      if (Output->tryLoadFromCache(Key))
>> -        return Error();
>> -    }
>> -
>> -    LTOLLVMContext BackendContext(Conf);
>> -    ErrorOr<std::unique_ptr<Module>> MOrErr =
>> -        parseBitcodeFile(MBRef, BackendContext);
>> -    assert(MOrErr && "Unable to load module in thread?");
>> -
>> -    auto AddOutputWrapper = [&](unsigned TaskId) {
>> -      assert(Task == TaskId && "Unexpexted TaskId mismatch");
>> -      return std::move(Output);
>> +      return thinBackend(Conf, Task, AddStream, **MOrErr, CombinedIndex,
>> +                         ImportList, DefinedGlobals, ModuleMap);
>>      };
>> -    return thinBackend(Conf, Task, AddOutputWrapper, **MOrErr,
>> CombinedIndex,
>> -                       ImportList, DefinedGlobals, ModuleMap);
>> +
>> +    if (!Cache)
>> +      return RunThinBackend(AddStream);
>> +
>> +    SmallString<40> Key;
>> +    // The module may be cached, this helps handling it.
>> +    computeCacheKey(Key, CombinedIndex, MBRef.getBufferIdentifier(),
>> +                    ImportList, ExportList, ResolvedODR, DefinedGlobals);
>> +    if (AddStreamFn CacheAddStream = Cache(Task, Key))
>> +      return RunThinBackend(CacheAddStream);
>> +
>> +    return Error();
>>    }
>>
>>    Error start(
>> @@ -574,8 +573,8 @@ public:
>>              const GVSummaryMapTy &DefinedGlobals,
>>              MapVector<StringRef, MemoryBufferRef> &ModuleMap) {
>>            Error E = runThinLTOBackendThread(
>> -              AddOutput, Task, MBRef, CombinedIndex, ImportList,
>> ExportList,
>> -              ResolvedODR, DefinedGlobals, ModuleMap);
>> +              AddStream, Cache, Task, MBRef, CombinedIndex, ImportList,
>> +              ExportList, ResolvedODR, DefinedGlobals, ModuleMap);
>>            if (E) {
>>              std::unique_lock<std::mutex> L(ErrMu);
>>              if (Err)
>> @@ -602,10 +601,10 @@ public:
>>  ThinBackend lto::createInProcessThinBackend(unsigned ParallelismLevel) {
>>    return [=](Config &Conf, ModuleSummaryIndex &CombinedIndex,
>>               const StringMap<GVSummaryMapTy> &ModuleToDefinedGVSummaries,
>> -             AddOutputFn AddOutput) {
>> +             AddStreamFn AddStream, NativeObjectCache Cache) {
>>      return llvm::make_unique<InProcessThinBackend>(
>>          Conf, CombinedIndex, ParallelismLevel,
>> ModuleToDefinedGVSummaries,
>> -        AddOutput);
>> +        AddStream, Cache);
>>    };
>>  }
>>
>> @@ -693,14 +692,15 @@ ThinBackend lto::createWriteIndexesThinB
>>                                                 std::string
>> LinkedObjectsFile) {
>>    return [=](Config &Conf, ModuleSummaryIndex &CombinedIndex,
>>               const StringMap<GVSummaryMapTy> &ModuleToDefinedGVSummaries,
>> -             AddOutputFn AddOutput) {
>> +             AddStreamFn AddStream, NativeObjectCache Cache) {
>>      return llvm::make_unique<WriteIndexesThinBackend>(
>>          Conf, CombinedIndex, ModuleToDefinedGVSummaries, OldPrefix,
>> NewPrefix,
>>          ShouldEmitImportsFiles, LinkedObjectsFile);
>>    };
>>  }
>>
>> -Error LTO::runThinLTO(AddOutputFn AddOutput, bool HasRegularLTO) {
>> +Error LTO::runThinLTO(AddStreamFn AddStream, NativeObjectCache Cache,
>> +                      bool HasRegularLTO) {
>>    if (ThinLTO.ModuleMap.empty())
>>      return Error();
>>
>> @@ -759,8 +759,9 @@ Error LTO::runThinLTO(AddOutputFn AddOut
>>    thinLTOResolveWeakForLinkerInIndex(ThinLTO.CombinedIndex,
>> isPrevailing,
>>                                       recordNewLinkage);
>>
>> -  std::unique_ptr<ThinBackendProc> BackendProc = ThinLTO.Backend(
>> -      Conf, ThinLTO.CombinedIndex, ModuleToDefinedGVSummaries,
>> AddOutput);
>> +  std::unique_ptr<ThinBackendProc> BackendProc =
>> +      ThinLTO.Backend(Conf, ThinLTO.CombinedIndex,
>> ModuleToDefinedGVSummaries,
>> +                      AddStream, Cache);
>>
>>    // Partition numbers for ThinLTO jobs start at 1 (see comments for
>>    // GlobalResolution in LTO.h). Task numbers, however, start at
>>
>> Modified: llvm/trunk/lib/LTO/LTOBackend.cpp
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/LTO/
>> LTOBackend.cpp?rev=282299&r1=282298&r2=282299&view=diff
>> ============================================================
>> ==================
>> --- llvm/trunk/lib/LTO/LTOBackend.cpp (original)
>> +++ llvm/trunk/lib/LTO/LTOBackend.cpp Fri Sep 23 16:33:43 2016
>> @@ -199,34 +199,20 @@ bool opt(Config &Conf, TargetMachine *TM
>>    return !Conf.PostOptModuleHook || Conf.PostOptModuleHook(Task, Mod);
>>  }
>>
>> -/// Monolithic LTO does not support caching (yet), this is a convenient
>> wrapper
>> -/// around AddOutput to workaround this.
>> -static AddOutputFn getUncachedOutputWrapper(AddOutputFn &AddOutput,
>> -                                            unsigned Task) {
>> -  return [Task, &AddOutput](unsigned TaskId) {
>> -    auto Output = AddOutput(Task);
>> -    if (Output->isCachingEnabled() && Output->tryLoadFromCache(""))
>> -      report_fatal_error("Cache hit without a valid key?");
>> -    assert(Task == TaskId && "Unexpexted TaskId mismatch");
>> -    return Output;
>> -  };
>> -}
>> -
>> -void codegen(Config &Conf, TargetMachine *TM, AddOutputFn AddOutput,
>> +void codegen(Config &Conf, TargetMachine *TM, AddStreamFn AddStream,
>>               unsigned Task, Module &Mod) {
>>    if (Conf.PreCodeGenModuleHook && !Conf.PreCodeGenModuleHook(Task,
>> Mod))
>>      return;
>>
>> -  auto Output = AddOutput(Task);
>> -  std::unique_ptr<raw_pwrite_stream> OS = Output->getStream();
>> +  auto Stream = AddStream(Task);
>>    legacy::PassManager CodeGenPasses;
>> -  if (TM->addPassesToEmitFile(CodeGenPasses, *OS,
>> +  if (TM->addPassesToEmitFile(CodeGenPasses, *Stream->OS,
>>                                TargetMachine::CGFT_ObjectFile))
>>      report_fatal_error("Failed to setup codegen");
>>    CodeGenPasses.run(Mod);
>>  }
>>
>> -void splitCodeGen(Config &C, TargetMachine *TM, AddOutputFn AddOutput,
>> +void splitCodeGen(Config &C, TargetMachine *TM, AddStreamFn AddStream,
>>                    unsigned ParallelCodeGenParallelismLevel,
>>                    std::unique_ptr<Module> Mod) {
>>    ThreadPool CodegenThreadPool(ParallelCodeGenParallelismLevel);
>> @@ -260,9 +246,7 @@ void splitCodeGen(Config &C, TargetMachi
>>                std::unique_ptr<TargetMachine> TM =
>>                    createTargetMachine(C, MPartInCtx->getTargetTriple(),
>> T);
>>
>> -              codegen(C, TM.get(),
>> -                      getUncachedOutputWrapper(AddOutput, ThreadId),
>> ThreadId,
>> -                      *MPartInCtx);
>> +              codegen(C, TM.get(), AddStream, ThreadId, *MPartInCtx);
>>              },
>>              // Pass BC using std::move to ensure that it get moved
>> rather than
>>              // copied into the thread's context.
>> @@ -299,7 +283,7 @@ static void handleAsmUndefinedRefs(Modul
>>    updateCompilerUsed(Mod, TM, AsmUndefinedRefs);
>>  }
>>
>> -Error lto::backend(Config &C, AddOutputFn AddOutput,
>> +Error lto::backend(Config &C, AddStreamFn AddStream,
>>                     unsigned ParallelCodeGenParallelismLevel,
>>                     std::unique_ptr<Module> Mod) {
>>    Expected<const Target *> TOrErr = initAndLookupTarget(C, *Mod);
>> @@ -316,15 +300,15 @@ Error lto::backend(Config &C, AddOutputF
>>        return Error();
>>
>>    if (ParallelCodeGenParallelismLevel == 1) {
>> -    codegen(C, TM.get(), getUncachedOutputWrapper(AddOutput, 0), 0,
>> *Mod);
>> +    codegen(C, TM.get(), AddStream, 0, *Mod);
>>    } else {
>> -    splitCodeGen(C, TM.get(), AddOutput, ParallelCodeGenParallelismLeve
>> l,
>> +    splitCodeGen(C, TM.get(), AddStream, ParallelCodeGenParallelismLeve
>> l,
>>                   std::move(Mod));
>>    }
>>    return Error();
>>  }
>>
>> -Error lto::thinBackend(Config &Conf, unsigned Task, AddOutputFn
>> AddOutput,
>> +Error lto::thinBackend(Config &Conf, unsigned Task, AddStreamFn
>> AddStream,
>>                         Module &Mod, ModuleSummaryIndex &CombinedIndex,
>>                         const FunctionImporter::ImportMapTy &ImportList,
>>                         const GVSummaryMapTy &DefinedGlobals,
>> @@ -339,7 +323,7 @@ Error lto::thinBackend(Config &Conf, uns
>>    handleAsmUndefinedRefs(Mod, *TM);
>>
>>    if (Conf.CodeGenOnly) {
>> -    codegen(Conf, TM.get(), AddOutput, Task, Mod);
>> +    codegen(Conf, TM.get(), AddStream, Task, Mod);
>>      return Error();
>>    }
>>
>> @@ -379,6 +363,6 @@ Error lto::thinBackend(Config &Conf, uns
>>    if (!opt(Conf, TM.get(), Task, Mod, /*IsThinLto=*/true))
>>      return Error();
>>
>> -  codegen(Conf, TM.get(), AddOutput, Task, Mod);
>> +  codegen(Conf, TM.get(), AddStream, Task, Mod);
>>    return Error();
>>  }
>>
>> Modified: llvm/trunk/tools/gold/gold-plugin.cpp
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/gold/
>> gold-plugin.cpp?rev=282299&r1=282298&r2=282299&view=diff
>> ============================================================
>> ==================
>> --- llvm/trunk/tools/gold/gold-plugin.cpp (original)
>> +++ llvm/trunk/tools/gold/gold-plugin.cpp Fri Sep 23 16:33:43 2016
>> @@ -675,24 +675,6 @@ static void getThinLTOOldAndNewPrefix(st
>>    NewPrefix = Split.second.str();
>>  }
>>
>> -namespace {
>> -// Define the LTOOutput handling
>> -class LTOOutput : public lto::NativeObjectOutput {
>> -  StringRef Path;
>> -
>> -public:
>> -  LTOOutput(StringRef Path) : Path(Path) {}
>> -  // Open the filename \p Path and allocate a stream.
>> -  std::unique_ptr<raw_pwrite_stream> getStream() override {
>> -    int FD;
>> -    std::error_code EC = sys::fs::openFileForWrite(Path, FD,
>> sys::fs::F_None);
>> -    if (EC)
>> -      message(LDPL_FATAL, "Could not open file: %s",
>> EC.message().c_str());
>> -    return llvm::make_unique<llvm::raw_fd_ostream>(FD, true);
>> -  }
>> -};
>> -}
>> -
>>  static std::unique_ptr<LTO> createLTO() {
>>    Config Conf;
>>    ThinBackend Backend;
>> @@ -831,21 +813,27 @@ static ld_plugin_status allSymbolsReadHo
>>    std::vector<uintptr_t> IsTemporary(MaxTasks);
>>    std::vector<SmallString<128>> Filenames(MaxTasks);
>>
>> -  auto AddOutput =
>> -      [&](size_t Task) -> std::unique_ptr<lto::NativeObjectOutput> {
>> -    auto &OutputName = Filenames[Task];
>> -    getOutputFileName(Filename, /*TempOutFile=*/!SaveTemps, OutputName,
>> +  auto AddStream =
>> +      [&](size_t Task) -> std::unique_ptr<lto::NativeObjectStream> {
>> +    IsTemporary[Task] = !SaveTemps;
>> +    getOutputFileName(Filename, /*TempOutFile=*/!SaveTemps,
>> Filenames[Task],
>>                        MaxTasks > 1 ? Task : -1);
>> -    IsTemporary[Task] = !SaveTemps && options::cache_dir.empty();
>> -    if (options::cache_dir.empty())
>> -      return llvm::make_unique<LTOOutput>(OutputName);
>> -
>> -    return llvm::make_unique<CacheObjectOutput>(
>> -        options::cache_dir,
>> -        [&OutputName](std::string EntryPath) { OutputName = EntryPath;
>> });
>> +    int FD;
>> +    std::error_code EC =
>> +        sys::fs::openFileForWrite(Filenames[Task], FD, sys::fs::F_None);
>> +    if (EC)
>> +      message(LDPL_FATAL, "Could not open file: %s",
>> EC.message().c_str());
>> +    return llvm::make_unique<lto::NativeObjectStream>(
>> +        llvm::make_unique<llvm::raw_fd_ostream>(FD, true));
>>    };
>>
>> -  check(Lto->run(AddOutput));
>> +  auto AddFile = [&](size_t Task, StringRef Path) { Filenames[Task] =
>> Path; };
>> +
>> +  NativeObjectCache Cache;
>> +  if (!options::cache_dir.empty())
>> +    Cache = localCache(options::cache_dir, AddFile);
>> +
>> +  check(Lto->run(AddStream, Cache));
>>
>>    if (options::TheOutputType == options::OT_DISABLE ||
>>        options::TheOutputType == options::OT_BC_ONLY)
>>
>> Modified: llvm/trunk/tools/llvm-lto2/llvm-lto2.cpp
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/llvm-
>> lto2/llvm-lto2.cpp?rev=282299&r1=282298&r2=282299&view=diff
>> ============================================================
>> ==================
>> --- llvm/trunk/tools/llvm-lto2/llvm-lto2.cpp (original)
>> +++ llvm/trunk/tools/llvm-lto2/llvm-lto2.cpp Fri Sep 23 16:33:43 2016
>> @@ -95,22 +95,6 @@ template <typename T> static T check(Err
>>    return T();
>>  }
>>
>> -namespace {
>> -// Define the LTOOutput handling
>> -class LTOOutput : public lto::NativeObjectOutput {
>> -  std::string Path;
>> -
>> -public:
>> -  LTOOutput(std::string Path) : Path(std::move(Path)) {}
>> -  std::unique_ptr<raw_pwrite_stream> getStream() override {
>> -    std::error_code EC;
>> -    auto S = llvm::make_unique<raw_fd_ostream>(Path, EC,
>> sys::fs::F_None);
>> -    check(EC, Path);
>> -    return std::move(S);
>> -  }
>> -};
>> -}
>> -
>>  int main(int argc, char **argv) {
>>    InitializeAllTargets();
>>    InitializeAllTargetMCs();
>> @@ -203,23 +187,28 @@ int main(int argc, char **argv) {
>>    if (HasErrors)
>>      return 1;
>>
>> -  auto AddOutput =
>> -      [&](size_t Task) -> std::unique_ptr<lto::NativeObjectOutput> {
>> +  auto AddStream =
>> +      [&](size_t Task) -> std::unique_ptr<lto::NativeObjectStream> {
>>      std::string Path = OutputFilename + "." + utostr(Task);
>> -    if (CacheDir.empty())
>> -      return llvm::make_unique<LTOOutput>(std::move(Path));
>>
>> -    return llvm::make_unique<CacheObjectOutput>(
>> -        CacheDir, [Path](std::string EntryPath) {
>> -          // Load the entry from the cache now.
>> -          auto ReloadedBufferOrErr = MemoryBuffer::getFile(EntryPath);
>> -          if (auto EC = ReloadedBufferOrErr.getError())
>> -            report_fatal_error(Twine("Can't reload cached file '") +
>> EntryPath +
>> -                               "': " + EC.message() + "\n");
>> +    std::error_code EC;
>> +    auto S = llvm::make_unique<raw_fd_ostream>(Path, EC,
>> sys::fs::F_None);
>> +    check(EC, Path);
>> +    return llvm::make_unique<lto::NativeObjectStream>(std::move(S));
>> +  };
>> +
>> +  auto AddFile = [&](size_t Task, StringRef Path) {
>> +    auto ReloadedBufferOrErr = MemoryBuffer::getFile(Path);
>> +    if (auto EC = ReloadedBufferOrErr.getError())
>> +      report_fatal_error(Twine("Can't reload cached file '") + Path +
>> "': " +
>> +                         EC.message() + "\n");
>>
>> -          *LTOOutput(Path).getStream() << (*ReloadedBufferOrErr)->
>> getBuffer();
>> -        });
>> +    *AddStream(Task)->OS << (*ReloadedBufferOrErr)->getBuffer();
>>    };
>>
>> -  check(Lto.run(AddOutput), "LTO::run failed");
>> +  NativeObjectCache Cache;
>> +  if (!CacheDir.empty())
>> +    Cache = localCache(CacheDir, AddFile);
>> +
>> +  check(Lto.run(AddStream, Cache), "LTO::run failed");
>>  }
>>
>>
>> _______________________________________________
>> llvm-commits mailing list
>> llvm-commits at lists.llvm.org
>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>>
>


-- 
-- 
Peter
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