From: Argyrios Kyrtzidis Date: Mon, 5 May 2014 21:55:51 +0000 (+0000) Subject: [Support/MemoryBuffer] Introduce a boolean parameter (false by default) 'IsVolatile... X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=32b6099a7729dbd97dc1e8551808c5f3f3517af3;p=oota-llvm.git [Support/MemoryBuffer] Introduce a boolean parameter (false by default) 'IsVolatile' for the open file functions. This provides a hint that the file may be changing often so mmap is avoided. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208007 91177308-0d34-0410-b5e6-96231b3b80d8 --- diff --git a/include/llvm/Support/MemoryBuffer.h b/include/llvm/Support/MemoryBuffer.h index 578c7e8eb88..268041e781d 100644 --- a/include/llvm/Support/MemoryBuffer.h +++ b/include/llvm/Support/MemoryBuffer.h @@ -67,34 +67,46 @@ public: /// MemoryBuffer if successful, otherwise returning null. If FileSize is /// specified, this means that the client knows that the file exists and that /// it has the specified size. + /// + /// \param IsVolatile true indicates that the file may be changing often. static error_code getFile(Twine Filename, OwningPtr &Result, int64_t FileSize = -1, - bool RequiresNullTerminator = true); + bool RequiresNullTerminator = true, + bool IsVolatile = false); static error_code getFile(Twine Filename, std::unique_ptr &Result, int64_t FileSize = -1, - bool RequiresNullTerminator = true); + bool RequiresNullTerminator = true, + bool IsVolatile = false); /// Given an already-open file descriptor, map some slice of it into a /// MemoryBuffer. The slice is specified by an \p Offset and \p MapSize. /// Since this is in the middle of a file, the buffer is not null terminated. + /// + /// \param IsVolatile true indicates that the file may be changing often. static error_code getOpenFileSlice(int FD, const char *Filename, OwningPtr &Result, - uint64_t MapSize, int64_t Offset); + uint64_t MapSize, int64_t Offset, + bool IsVolatile = false); static error_code getOpenFileSlice(int FD, const char *Filename, std::unique_ptr &Result, - uint64_t MapSize, int64_t Offset); + uint64_t MapSize, int64_t Offset, + bool IsVolatile = false); /// Given an already-open file descriptor, read the file and return a /// MemoryBuffer. + /// + /// \param IsVolatile true indicates that the file may be changing often. static error_code getOpenFile(int FD, const char *Filename, OwningPtr &Result, uint64_t FileSize, - bool RequiresNullTerminator = true); + bool RequiresNullTerminator = true, + bool IsVolatile = false); static error_code getOpenFile(int FD, const char *Filename, std::unique_ptr &Result, uint64_t FileSize, - bool RequiresNullTerminator = true); + bool RequiresNullTerminator = true, + bool IsVolatile = false); /// getMemBuffer - Open the specified memory range as a MemoryBuffer. Note /// that InputData must be null terminated if RequiresNullTerminator is true. diff --git a/lib/Support/MemoryBuffer.cpp b/lib/Support/MemoryBuffer.cpp index 773ccfd6f73..dc615d2a421 100644 --- a/lib/Support/MemoryBuffer.cpp +++ b/lib/Support/MemoryBuffer.cpp @@ -252,25 +252,29 @@ static error_code getMemoryBufferForStream(int FD, static error_code getFileAux(const char *Filename, std::unique_ptr &Result, int64_t FileSize, - bool RequiresNullTerminator); + bool RequiresNullTerminator, + bool IsVolatile); error_code MemoryBuffer::getFile(Twine Filename, std::unique_ptr &Result, int64_t FileSize, - bool RequiresNullTerminator) { + bool RequiresNullTerminator, + bool IsVolatile) { // Ensure the path is null terminated. SmallString<256> PathBuf; StringRef NullTerminatedName = Filename.toNullTerminatedStringRef(PathBuf); return getFileAux(NullTerminatedName.data(), Result, FileSize, - RequiresNullTerminator); + RequiresNullTerminator, IsVolatile); } error_code MemoryBuffer::getFile(Twine Filename, OwningPtr &Result, int64_t FileSize, - bool RequiresNullTerminator) { + bool RequiresNullTerminator, + bool IsVolatile) { std::unique_ptr MB; - error_code ec = getFile(Filename, MB, FileSize, RequiresNullTerminator); + error_code ec = getFile(Filename, MB, FileSize, RequiresNullTerminator, + IsVolatile); Result = std::move(MB); return ec; } @@ -278,18 +282,20 @@ error_code MemoryBuffer::getFile(Twine Filename, static error_code getOpenFileImpl(int FD, const char *Filename, std::unique_ptr &Result, uint64_t FileSize, uint64_t MapSize, - int64_t Offset, bool RequiresNullTerminator); + int64_t Offset, bool RequiresNullTerminator, + bool IsVolatile); static error_code getFileAux(const char *Filename, std::unique_ptr &Result, int64_t FileSize, - bool RequiresNullTerminator) { + bool RequiresNullTerminator, + bool IsVolatile) { int FD; error_code EC = sys::fs::openFileForRead(Filename, FD); if (EC) return EC; error_code ret = getOpenFileImpl(FD, Filename, Result, FileSize, FileSize, 0, - RequiresNullTerminator); + RequiresNullTerminator, IsVolatile); close(FD); return ret; } @@ -348,7 +354,8 @@ static bool shouldUseMmap(int FD, static error_code getOpenFileImpl(int FD, const char *Filename, std::unique_ptr &Result, uint64_t FileSize, uint64_t MapSize, - int64_t Offset, bool RequiresNullTerminator) { + int64_t Offset, bool RequiresNullTerminator, + bool IsVolatile) { static int PageSize = sys::process::get_self()->page_size(); // Default is to map the full file. @@ -374,7 +381,8 @@ static error_code getOpenFileImpl(int FD, const char *Filename, MapSize = FileSize; } - if (shouldUseMmap(FD, FileSize, MapSize, Offset, RequiresNullTerminator, + if (!IsVolatile && + shouldUseMmap(FD, FileSize, MapSize, Offset, RequiresNullTerminator, PageSize)) { error_code EC; Result.reset(new (NamedBufferAlloc(Filename)) MemoryBufferMMapFile( @@ -428,33 +436,39 @@ static error_code getOpenFileImpl(int FD, const char *Filename, error_code MemoryBuffer::getOpenFile(int FD, const char *Filename, std::unique_ptr &Result, uint64_t FileSize, - bool RequiresNullTerminator) { + bool RequiresNullTerminator, + bool IsVolatile) { return getOpenFileImpl(FD, Filename, Result, FileSize, FileSize, 0, - RequiresNullTerminator); + RequiresNullTerminator, IsVolatile); } error_code MemoryBuffer::getOpenFile(int FD, const char *Filename, OwningPtr &Result, uint64_t FileSize, - bool RequiresNullTerminator) { + bool RequiresNullTerminator, + bool IsVolatile) { std::unique_ptr MB; error_code ec = getOpenFileImpl(FD, Filename, MB, FileSize, FileSize, 0, - RequiresNullTerminator); + RequiresNullTerminator, IsVolatile); Result = std::move(MB); return ec; } error_code MemoryBuffer::getOpenFileSlice(int FD, const char *Filename, std::unique_ptr &Result, - uint64_t MapSize, int64_t Offset) { - return getOpenFileImpl(FD, Filename, Result, -1, MapSize, Offset, false); + uint64_t MapSize, int64_t Offset, + bool IsVolatile) { + return getOpenFileImpl(FD, Filename, Result, -1, MapSize, Offset, false, + IsVolatile); } error_code MemoryBuffer::getOpenFileSlice(int FD, const char *Filename, OwningPtr &Result, - uint64_t MapSize, int64_t Offset) { + uint64_t MapSize, int64_t Offset, + bool IsVolatile) { std::unique_ptr MB; - error_code ec = getOpenFileImpl(FD, Filename, MB, -1, MapSize, Offset, false); + error_code ec = getOpenFileImpl(FD, Filename, MB, -1, MapSize, Offset, false, + IsVolatile); Result = std::move(MB); return ec; }