It's not necessary to do rounding for alloca operations when the requested
alignment is equal to the stack alignment.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@40004 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Support/MemoryBuffer.cpp b/lib/Support/MemoryBuffer.cpp
new file mode 100644
index 0000000..43eb181
--- /dev/null
+++ b/lib/Support/MemoryBuffer.cpp
@@ -0,0 +1,259 @@
+//===--- MemoryBuffer.cpp - Memory Buffer implementation ------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file was developed by Chris Lattner and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the MemoryBuffer interface.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/System/MappedFile.h"
+#include "llvm/System/Process.h"
+#include "llvm/System/Program.h"
+#include <cassert>
+#include <cstdio>
+#include <cstring>
+#include <cerrno>
+using namespace llvm;
+
+//===----------------------------------------------------------------------===//
+// MemoryBuffer implementation itself.
+//===----------------------------------------------------------------------===//
+
+MemoryBuffer::~MemoryBuffer() {
+ if (MustDeleteBuffer)
+ delete [] BufferStart;
+}
+
+/// initCopyOf - Initialize this source buffer with a copy of the specified
+/// memory range. We make the copy so that we can null terminate it
+/// successfully.
+void MemoryBuffer::initCopyOf(const char *BufStart, const char *BufEnd) {
+ size_t Size = BufEnd-BufStart;
+ BufferStart = new char[Size+1];
+ BufferEnd = BufferStart+Size;
+ memcpy(const_cast<char*>(BufferStart), BufStart, Size);
+ *const_cast<char*>(BufferEnd) = 0; // Null terminate buffer.
+ MustDeleteBuffer = true;
+}
+
+/// init - Initialize this MemoryBuffer as a reference to externally allocated
+/// memory, memory that we know is already null terminated.
+void MemoryBuffer::init(const char *BufStart, const char *BufEnd) {
+ assert(BufEnd[0] == 0 && "Buffer is not null terminated!");
+ BufferStart = BufStart;
+ BufferEnd = BufEnd;
+ MustDeleteBuffer = false;
+}
+
+//===----------------------------------------------------------------------===//
+// MemoryBufferMem implementation.
+//===----------------------------------------------------------------------===//
+
+namespace {
+class MemoryBufferMem : public MemoryBuffer {
+ std::string FileID;
+public:
+ MemoryBufferMem(const char *Start, const char *End, const char *FID)
+ : FileID(FID) {
+ init(Start, End);
+ }
+
+ virtual const char *getBufferIdentifier() const {
+ return FileID.c_str();
+ }
+};
+}
+
+/// getMemBuffer - Open the specified memory range as a MemoryBuffer. Note
+/// that EndPtr[0] must be a null byte and be accessible!
+MemoryBuffer *MemoryBuffer::getMemBuffer(const char *StartPtr,
+ const char *EndPtr,
+ const char *BufferName) {
+ return new MemoryBufferMem(StartPtr, EndPtr, BufferName);
+}
+
+/// getNewUninitMemBuffer - Allocate a new MemoryBuffer of the specified size
+/// that is completely initialized to zeros. Note that the caller should
+/// initialize the memory allocated by this method. The memory is owned by
+/// the MemoryBuffer object.
+MemoryBuffer *MemoryBuffer::getNewUninitMemBuffer(unsigned Size,
+ const char *BufferName) {
+ char *Buf = new char[Size+1];
+ Buf[Size] = 0;
+ MemoryBufferMem *SB = new MemoryBufferMem(Buf, Buf+Size, BufferName);
+ // The memory for this buffer is owned by the MemoryBuffer.
+ SB->MustDeleteBuffer = true;
+ return SB;
+}
+
+/// getNewMemBuffer - Allocate a new MemoryBuffer of the specified size that
+/// is completely initialized to zeros. Note that the caller should
+/// initialize the memory allocated by this method. The memory is owned by
+/// the MemoryBuffer object.
+MemoryBuffer *MemoryBuffer::getNewMemBuffer(unsigned Size,
+ const char *BufferName) {
+ MemoryBuffer *SB = getNewUninitMemBuffer(Size, BufferName);
+ memset(const_cast<char*>(SB->getBufferStart()), 0, Size+1);
+ return SB;
+}
+
+
+//===----------------------------------------------------------------------===//
+// MemoryBufferMMapFile implementation.
+//===----------------------------------------------------------------------===//
+
+namespace {
+class MemoryBufferMMapFile : public MemoryBuffer {
+ sys::MappedFile File;
+public:
+ MemoryBufferMMapFile() {}
+
+ bool open(const sys::Path &Filename, std::string *ErrStr);
+
+ virtual const char *getBufferIdentifier() const {
+ return File.path().c_str();
+ }
+
+ ~MemoryBufferMMapFile();
+};
+}
+
+bool MemoryBufferMMapFile::open(const sys::Path &Filename,
+ std::string *ErrStr) {
+ // FIXME: This does an extra stat syscall to figure out the size, but we
+ // already know the size!
+ bool Failure = File.open(Filename, sys::MappedFile::READ_ACCESS, ErrStr);
+ if (Failure) return true;
+
+ if (!File.map(ErrStr))
+ return true;
+
+ size_t Size = File.size();
+
+ static unsigned PageSize = sys::Process::GetPageSize();
+ assert(((PageSize & (PageSize-1)) == 0) && PageSize &&
+ "Page size is not a power of 2!");
+
+ // If this file is not an exact multiple of the system page size (common
+ // case), then the OS has zero terminated the buffer for us.
+ if ((Size & (PageSize-1))) {
+ init(File.charBase(), File.charBase()+Size);
+ } else {
+ // Otherwise, we allocate a new memory buffer and copy the data over
+ initCopyOf(File.charBase(), File.charBase()+Size);
+
+ // No need to keep the file mapped any longer.
+ File.unmap();
+ }
+ return false;
+}
+
+MemoryBufferMMapFile::~MemoryBufferMMapFile() {
+ if (File.isMapped())
+ File.unmap();
+}
+
+//===----------------------------------------------------------------------===//
+// MemoryBuffer::getFile implementation.
+//===----------------------------------------------------------------------===//
+
+MemoryBuffer *MemoryBuffer::getFile(const char *FilenameStart, unsigned FnSize,
+ std::string *ErrStr, int64_t FileSize){
+ // FIXME: it would be nice if PathWithStatus didn't copy the filename into a
+ // temporary string. :(
+ sys::PathWithStatus P(FilenameStart, FnSize);
+#if 1
+ MemoryBufferMMapFile *M = new MemoryBufferMMapFile();
+ if (!M->open(P, ErrStr))
+ return M;
+ delete M;
+ return 0;
+#else
+ // FIXME: We need an efficient and portable method to open a file and then use
+ // 'read' to copy the bits out. The unix implementation is below. This is
+ // an important optimization for clients that want to open large numbers of
+ // small files (using mmap on everything can easily exhaust address space!).
+
+ // If the user didn't specify a filesize, do a stat to find it.
+ if (FileSize == -1) {
+ const sys::FileStatus *FS = P.getFileStatus();
+ if (FS == 0) return 0; // Error stat'ing file.
+
+ FileSize = FS->fileSize;
+ }
+
+ // If the file is larger than some threshold, use mmap, otherwise use 'read'.
+ if (FileSize >= 4096*4) {
+ MemoryBufferMMapFile *M = new MemoryBufferMMapFile();
+ if (!M->open(P, ErrStr))
+ return M;
+ delete M;
+ return 0;
+ }
+
+ MemoryBuffer *SB = getNewUninitMemBuffer(FileSize, FilenameStart);
+ char *BufPtr = const_cast<char*>(SB->getBufferStart());
+
+ int FD = ::open(FilenameStart, O_RDONLY);
+ if (FD == -1) {
+ delete SB;
+ return 0;
+ }
+
+ unsigned BytesLeft = FileSize;
+ while (BytesLeft) {
+ ssize_t NumRead = ::read(FD, BufPtr, BytesLeft);
+ if (NumRead != -1) {
+ BytesLeft -= NumRead;
+ BufPtr += NumRead;
+ } else if (errno == EINTR) {
+ // try again
+ } else {
+ // error reading.
+ close(FD);
+ delete SB;
+ return 0;
+ }
+ }
+ close(FD);
+
+ return SB;
+#endif
+}
+
+
+//===----------------------------------------------------------------------===//
+// MemoryBuffer::getSTDIN implementation.
+//===----------------------------------------------------------------------===//
+
+namespace {
+class STDINBufferFile : public MemoryBuffer {
+public:
+ virtual const char *getBufferIdentifier() const {
+ return "<stdin>";
+ }
+};
+}
+
+MemoryBuffer *MemoryBuffer::getSTDIN() {
+ char Buffer[4096*4];
+
+ std::vector<char> FileData;
+
+ // Read in all of the data from stdin, we cannot mmap stdin.
+ sys::Program::ChangeStdinToBinary();
+ while (size_t ReadBytes = fread(Buffer, 1, 4096*4, stdin))
+ FileData.insert(FileData.end(), Buffer, Buffer+ReadBytes);
+
+ FileData.push_back(0); // &FileData[Size] is invalid. So is &*FileData.end().
+ size_t Size = FileData.size();
+ MemoryBuffer *B = new STDINBufferFile();
+ B->initCopyOf(&FileData[0], &FileData[Size-1]);
+ return B;
+}