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Update LLVM for 3.5 rebase (r209712).
[android-x86/external-llvm.git] / lib / Support / MemoryBuffer.cpp
index 2d593a8..629d885 100644 (file)
@@ -12,7 +12,6 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Support/MemoryBuffer.h"
-#include "llvm/ADT/OwningPtr.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/Config/config.h"
 #include "llvm/Support/Errno.h"
 #include <cstdio>
 #include <cstring>
 #include <new>
-#include <sys/stat.h>
 #include <sys/types.h>
 #if !defined(_MSC_VER) && !defined(__MINGW32__)
 #include <unistd.h>
 #else
 #include <io.h>
-// Simplistic definitinos of these macros for use in getOpenFile.
-#ifndef S_ISREG
-#define S_ISREG(x) (1)
-#endif
-#ifndef S_ISBLK
-#define S_ISBLK(x) (0)
-#endif
 #endif
 using namespace llvm;
 
@@ -117,7 +108,7 @@ MemoryBuffer *MemoryBuffer::getMemBuffer(StringRef InputData,
 MemoryBuffer *MemoryBuffer::getMemBufferCopy(StringRef InputData,
                                              StringRef BufferName) {
   MemoryBuffer *Buf = getNewUninitMemBuffer(InputData.size(), BufferName);
-  if (!Buf) return 0;
+  if (!Buf) return nullptr;
   memcpy(const_cast<char*>(Buf->getBufferStart()), InputData.data(),
          InputData.size());
   return Buf;
@@ -137,7 +128,7 @@ MemoryBuffer *MemoryBuffer::getNewUninitMemBuffer(size_t Size,
       RoundUpToAlignment(sizeof(MemoryBufferMem) + BufferName.size() + 1, 16);
   size_t RealLen = AlignedStringLen + Size + 1;
   char *Mem = static_cast<char*>(operator new(RealLen, std::nothrow));
-  if (!Mem) return 0;
+  if (!Mem) return nullptr;
 
   // The name is stored after the class itself.
   CopyStringRef(Mem + sizeof(MemoryBufferMem), BufferName);
@@ -155,7 +146,7 @@ MemoryBuffer *MemoryBuffer::getNewUninitMemBuffer(size_t Size,
 /// the MemoryBuffer object.
 MemoryBuffer *MemoryBuffer::getNewMemBuffer(size_t Size, StringRef BufferName) {
   MemoryBuffer *SB = getNewUninitMemBuffer(Size, BufferName);
-  if (!SB) return 0;
+  if (!SB) return nullptr;
   memset(const_cast<char*>(SB->getBufferStart()), 0, Size);
   return SB;
 }
@@ -173,15 +164,6 @@ error_code MemoryBuffer::getFileOrSTDIN(StringRef Filename,
   return getFile(Filename, Result, FileSize);
 }
 
-error_code MemoryBuffer::getFileOrSTDIN(StringRef Filename,
-                                        OwningPtr<MemoryBuffer> &Result,
-                                        int64_t FileSize) {
-  std::unique_ptr<MemoryBuffer> MB;
-  error_code ec = getFileOrSTDIN(Filename, MB, FileSize);
-  Result = std::move(MB);
-  return ec;
-}
-
 
 //===----------------------------------------------------------------------===//
 // MemoryBuffer::getFile implementation.
@@ -252,44 +234,38 @@ static error_code getMemoryBufferForStream(int FD,
 static error_code getFileAux(const char *Filename,
                              std::unique_ptr<MemoryBuffer> &Result,
                              int64_t FileSize,
-                             bool RequiresNullTerminator);
+                             bool RequiresNullTerminator,
+                             bool IsVolatileSize);
 
 error_code MemoryBuffer::getFile(Twine Filename,
                                  std::unique_ptr<MemoryBuffer> &Result,
                                  int64_t FileSize,
-                                 bool RequiresNullTerminator) {
+                                 bool RequiresNullTerminator,
+                                 bool IsVolatileSize) {
   // Ensure the path is null terminated.
   SmallString<256> PathBuf;
   StringRef NullTerminatedName = Filename.toNullTerminatedStringRef(PathBuf);
   return getFileAux(NullTerminatedName.data(), Result, FileSize,
-                    RequiresNullTerminator);
-}
-
-error_code MemoryBuffer::getFile(Twine Filename,
-                                 OwningPtr<MemoryBuffer> &Result,
-                                 int64_t FileSize,
-                                 bool RequiresNullTerminator) {
-  std::unique_ptr<MemoryBuffer> MB;
-  error_code ec = getFile(Filename, MB, FileSize, RequiresNullTerminator);
-  Result = std::move(MB);
-  return ec;
+                    RequiresNullTerminator, IsVolatileSize);
 }
 
 static error_code getOpenFileImpl(int FD, const char *Filename,
                                   std::unique_ptr<MemoryBuffer> &Result,
                                   uint64_t FileSize, uint64_t MapSize,
-                                  int64_t Offset, bool RequiresNullTerminator);
+                                  int64_t Offset, bool RequiresNullTerminator,
+                                  bool IsVolatileSize);
 
 static error_code getFileAux(const char *Filename,
                              std::unique_ptr<MemoryBuffer> &Result, int64_t FileSize,
-                             bool RequiresNullTerminator) {
+                             bool RequiresNullTerminator,
+                             bool IsVolatileSize) {
   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, IsVolatileSize);
   close(FD);
   return ret;
 }
@@ -299,7 +275,14 @@ static bool shouldUseMmap(int FD,
                           size_t MapSize,
                           off_t Offset,
                           bool RequiresNullTerminator,
-                          int PageSize) {
+                          int PageSize,
+                          bool IsVolatileSize) {
+  // mmap may leave the buffer without null terminator if the file size changed
+  // by the time the last page is mapped in, so avoid it if the file size is
+  // likely to change.
+  if (IsVolatileSize)
+    return false;
+
   // We don't use mmap for small files because this can severely fragment our
   // address space.
   if (MapSize < 4 * 4096 || MapSize < (unsigned)PageSize)
@@ -315,9 +298,8 @@ static bool shouldUseMmap(int FD,
   // RequiresNullTerminator = false and MapSize != -1.
   if (FileSize == size_t(-1)) {
     sys::fs::file_status Status;
-    error_code EC = sys::fs::status(FD, Status);
-    if (EC)
-      return EC;
+    if (sys::fs::status(FD, Status))
+      return false;
     FileSize = Status.getSize();
   }
 
@@ -328,15 +310,6 @@ static bool shouldUseMmap(int FD,
   if (End != FileSize)
     return false;
 
-#if defined(_WIN32) || defined(__CYGWIN__)
-  // Don't peek the next page if file is multiple of *physical* pagesize(4k)
-  // but is not multiple of AllocationGranularity(64k),
-  // when a null terminator is required.
-  // FIXME: It's not good to hardcode 4096 here. dwPageSize shows 4096.
-  if ((FileSize & (4096 - 1)) == 0)
-    return false;
-#endif
-
   // Don't try to map files that are exactly a multiple of the system page size
   // if we need a null terminator.
   if ((FileSize & (PageSize -1)) == 0)
@@ -348,7 +321,8 @@ static bool shouldUseMmap(int FD,
 static error_code getOpenFileImpl(int FD, const char *Filename,
                                   std::unique_ptr<MemoryBuffer> &Result,
                                   uint64_t FileSize, uint64_t MapSize,
-                                  int64_t Offset, bool RequiresNullTerminator) {
+                                  int64_t Offset, bool RequiresNullTerminator,
+                                  bool IsVolatileSize) {
   static int PageSize = sys::process::get_self()->page_size();
 
   // Default is to map the full file.
@@ -375,7 +349,7 @@ static error_code getOpenFileImpl(int FD, const char *Filename,
   }
 
   if (shouldUseMmap(FD, FileSize, MapSize, Offset, RequiresNullTerminator,
-                    PageSize)) {
+                    PageSize, IsVolatileSize)) {
     error_code EC;
     Result.reset(new (NamedBufferAlloc(Filename)) MemoryBufferMMapFile(
         RequiresNullTerminator, FD, MapSize, Offset, EC));
@@ -412,9 +386,7 @@ static error_code getOpenFileImpl(int FD, const char *Filename,
       return error_code(errno, posix_category());
     }
     if (NumRead == 0) {
-      assert(0 && "We got inaccurate FileSize value or fstat reported an "
-                   "invalid file size.");
-      *BufPtr = '\0'; // null-terminate at the actual size.
+      memset(BufPtr, 0, BytesLeft); // zero-initialize rest of the buffer.
       break;
     }
     BytesLeft -= NumRead;
@@ -428,35 +400,18 @@ static error_code getOpenFileImpl(int FD, const char *Filename,
 error_code MemoryBuffer::getOpenFile(int FD, const char *Filename,
                                      std::unique_ptr<MemoryBuffer> &Result,
                                      uint64_t FileSize,
-                                     bool RequiresNullTerminator) {
+                                     bool RequiresNullTerminator,
+                                     bool IsVolatileSize) {
   return getOpenFileImpl(FD, Filename, Result, FileSize, FileSize, 0,
-                         RequiresNullTerminator);
-}
-
-error_code MemoryBuffer::getOpenFile(int FD, const char *Filename,
-                                     OwningPtr<MemoryBuffer> &Result,
-                                     uint64_t FileSize,
-                                     bool RequiresNullTerminator) {
-  std::unique_ptr<MemoryBuffer> MB;
-  error_code ec = getOpenFileImpl(FD, Filename, MB, FileSize, FileSize, 0,
-                                  RequiresNullTerminator);
-  Result = std::move(MB);
-  return ec;
+                         RequiresNullTerminator, IsVolatileSize);
 }
 
 error_code MemoryBuffer::getOpenFileSlice(int FD, const char *Filename,
                                           std::unique_ptr<MemoryBuffer> &Result,
-                                          uint64_t MapSize, int64_t Offset) {
-  return getOpenFileImpl(FD, Filename, Result, -1, MapSize, Offset, false);
-}
-
-error_code MemoryBuffer::getOpenFileSlice(int FD, const char *Filename,
-                                          OwningPtr<MemoryBuffer> &Result,
-                                          uint64_t MapSize, int64_t Offset) {
-  std::unique_ptr<MemoryBuffer> MB;
-  error_code ec = getOpenFileImpl(FD, Filename, MB, -1, MapSize, Offset, false);
-  Result = std::move(MB);
-  return ec;
+                                          uint64_t MapSize, int64_t Offset,
+                                          bool IsVolatileSize) {
+  return getOpenFileImpl(FD, Filename, Result, -1, MapSize, Offset, false,
+                         IsVolatileSize);
 }
 
 //===----------------------------------------------------------------------===//
@@ -472,10 +427,3 @@ error_code MemoryBuffer::getSTDIN(std::unique_ptr<MemoryBuffer> &Result) {
 
   return getMemoryBufferForStream(0, "<stdin>", Result);
 }
-
-error_code MemoryBuffer::getSTDIN(OwningPtr<MemoryBuffer> &Result) {
-  std::unique_ptr<MemoryBuffer> MB;
-  error_code ec = getSTDIN(MB);
-  Result = std::move(MB);
-  return ec;
-}