[llvm-commits] [llvm] r106839 - in /llvm/trunk: include/llvm/Support/MemoryBuffer.h lib/Support/MemoryBuffer.cpp
Benjamin Kramer
benny.kra at googlemail.com
Fri Jun 25 04:50:41 PDT 2010
Author: d0k
Date: Fri Jun 25 06:50:40 2010
New Revision: 106839
URL: http://llvm.org/viewvc/llvm-project?rev=106839&view=rev
Log:
Tweak MemoryBuffer to allocate the class itself, the name and possibly the
buffer in the same chunk of memory.
2 less mallocs for every uninitialized MemoryBuffer and 1 less malloc for every
MemoryBuffer pointing to a memory range translate into 20% less mallocs on
clang -cc1 -Eonly Cocoa_h.m.
Modified:
llvm/trunk/include/llvm/Support/MemoryBuffer.h
llvm/trunk/lib/Support/MemoryBuffer.cpp
Modified: llvm/trunk/include/llvm/Support/MemoryBuffer.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/MemoryBuffer.h?rev=106839&r1=106838&r2=106839&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Support/MemoryBuffer.h (original)
+++ llvm/trunk/include/llvm/Support/MemoryBuffer.h Fri Jun 25 06:50:40 2010
@@ -35,13 +35,11 @@
const char *BufferStart; // Start of the buffer.
const char *BufferEnd; // End of the buffer.
- /// MustDeleteBuffer - True if we allocated this buffer. If so, the
- /// destructor must know the delete[] it.
- bool MustDeleteBuffer;
+ MemoryBuffer(const MemoryBuffer &); // DO NOT IMPLEMENT
+ MemoryBuffer &operator=(const MemoryBuffer &); // DO NOT IMPLEMENT
protected:
- MemoryBuffer() : MustDeleteBuffer(false) {}
+ MemoryBuffer() {}
void init(const char *BufStart, const char *BufEnd);
- void initCopyOf(const char *BufStart, const char *BufEnd);
public:
virtual ~MemoryBuffer();
@@ -75,20 +73,19 @@
/// getMemBuffer - Open the specified memory range as a MemoryBuffer. Note
/// that EndPtr[0] must be a null byte and be accessible!
static MemoryBuffer *getMemBuffer(StringRef InputData,
- const char *BufferName = "");
+ StringRef BufferName = "");
/// getMemBufferCopy - Open the specified memory range as a MemoryBuffer,
/// copying the contents and taking ownership of it. This has no requirements
/// on EndPtr[0].
static MemoryBuffer *getMemBufferCopy(StringRef InputData,
- const char *BufferName = "");
+ StringRef BufferName = "");
/// 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.
- static MemoryBuffer *getNewMemBuffer(size_t Size,
- const char *BufferName = "");
+ static MemoryBuffer *getNewMemBuffer(size_t Size, StringRef BufferName = "");
/// getNewUninitMemBuffer - Allocate a new MemoryBuffer of the specified size
/// that is not initialized. Note that the caller should initialize the
Modified: llvm/trunk/lib/Support/MemoryBuffer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/MemoryBuffer.cpp?rev=106839&r1=106838&r2=106839&view=diff
==============================================================================
--- llvm/trunk/lib/Support/MemoryBuffer.cpp (original)
+++ llvm/trunk/lib/Support/MemoryBuffer.cpp Fri Jun 25 06:50:40 2010
@@ -14,6 +14,7 @@
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/ADT/OwningPtr.h"
#include "llvm/ADT/SmallString.h"
+#include "llvm/Support/MathExtras.h"
#include "llvm/System/Errno.h"
#include "llvm/System/Path.h"
#include "llvm/System/Process.h"
@@ -37,22 +38,7 @@
// MemoryBuffer implementation itself.
//===----------------------------------------------------------------------===//
-MemoryBuffer::~MemoryBuffer() {
- if (MustDeleteBuffer)
- free((void*)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 = (char *)malloc(Size+1);
- BufferEnd = BufferStart+Size;
- memcpy(const_cast<char*>(BufferStart), BufStart, Size);
- *const_cast<char*>(BufferEnd) = 0; // Null terminate buffer.
- MustDeleteBuffer = true;
-}
+MemoryBuffer::~MemoryBuffer() { }
/// init - Initialize this MemoryBuffer as a reference to externally allocated
/// memory, memory that we know is already null terminated.
@@ -60,27 +46,38 @@
assert(BufEnd[0] == 0 && "Buffer is not null terminated!");
BufferStart = BufStart;
BufferEnd = BufEnd;
- MustDeleteBuffer = false;
}
//===----------------------------------------------------------------------===//
// MemoryBufferMem implementation.
//===----------------------------------------------------------------------===//
+/// CopyStringRef - Copies contents of a StringRef into a block of memory and
+/// null-terminates it.
+static void CopyStringRef(char *Memory, StringRef Data) {
+ memcpy(Memory, Data.data(), Data.size());
+ Memory[Data.size()] = 0; // Null terminate string.
+}
+
+/// GetNamedBuffer - Allocates a new MemoryBuffer with Name copied after it.
+template <typename T>
+static T* GetNamedBuffer(StringRef Buffer, StringRef Name) {
+ char *Mem = static_cast<char*>(operator new(sizeof(T) + Name.size() + 1));
+ CopyStringRef(Mem + sizeof(T), Name);
+ return new (Mem) T(Buffer);
+}
+
namespace {
+/// MemoryBufferMem - Named MemoryBuffer pointing to a block of memory.
class MemoryBufferMem : public MemoryBuffer {
- std::string FileID;
public:
- MemoryBufferMem(StringRef InputData, StringRef FID, bool Copy = false)
- : FileID(FID) {
- if (!Copy)
- init(InputData.data(), InputData.data()+InputData.size());
- else
- initCopyOf(InputData.data(), InputData.data()+InputData.size());
+ MemoryBufferMem(StringRef InputData) {
+ init(InputData.begin(), InputData.end());
}
-
+
virtual const char *getBufferIdentifier() const {
- return FileID.c_str();
+ // The name is stored after the class itself.
+ return reinterpret_cast<const char*>(this + 1);
}
};
}
@@ -88,42 +85,55 @@
/// getMemBuffer - Open the specified memory range as a MemoryBuffer. Note
/// that EndPtr[0] must be a null byte and be accessible!
MemoryBuffer *MemoryBuffer::getMemBuffer(StringRef InputData,
- const char *BufferName) {
- return new MemoryBufferMem(InputData, BufferName);
+ StringRef BufferName) {
+ return GetNamedBuffer<MemoryBufferMem>(InputData, BufferName);
}
/// getMemBufferCopy - Open the specified memory range as a MemoryBuffer,
/// copying the contents and taking ownership of it. This has no requirements
/// on EndPtr[0].
MemoryBuffer *MemoryBuffer::getMemBufferCopy(StringRef InputData,
- const char *BufferName) {
- return new MemoryBufferMem(InputData, BufferName, true);
+ StringRef BufferName) {
+ MemoryBuffer *Buf = getNewUninitMemBuffer(InputData.size(), BufferName);
+ if (!Buf) return 0;
+ memcpy(const_cast<char*>(Buf->getBufferStart()), InputData.data(),
+ InputData.size());
+ return Buf;
}
/// 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.
+/// that is not initialized. Note that the caller should initialize the
+/// memory allocated by this method. The memory is owned by the MemoryBuffer
+/// object.
MemoryBuffer *MemoryBuffer::getNewUninitMemBuffer(size_t Size,
StringRef BufferName) {
- char *Buf = (char *)malloc(Size+1);
- if (!Buf) return 0;
- Buf[Size] = 0;
- MemoryBufferMem *SB = new MemoryBufferMem(StringRef(Buf, Size), BufferName);
- // The memory for this buffer is owned by the MemoryBuffer.
- SB->MustDeleteBuffer = true;
- return SB;
+ // Allocate space for the MemoryBuffer, the data and the name. It is important
+ // that MemoryBuffer and data are aligned so PointerIntPair works with them.
+ size_t AlignedStringLen =
+ RoundUpToAlignment(sizeof(MemoryBufferMem) + BufferName.size() + 1,
+ sizeof(void*)); // TODO: Is sizeof(void*) enough?
+ size_t RealLen = AlignedStringLen + Size + 1;
+ char *Mem = static_cast<char*>(operator new(RealLen, std::nothrow));
+ if (!Mem) return 0;
+
+ // The name is stored after the class itself.
+ CopyStringRef(Mem + sizeof(MemoryBufferMem), BufferName);
+
+ // The buffer begins after the name and must be aligned.
+ char *Buf = Mem + AlignedStringLen;
+ Buf[Size] = 0; // Null terminate buffer.
+
+ return new (Mem) MemoryBufferMem(StringRef(Buf, Size));
}
/// 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(size_t Size,
- const char *BufferName) {
+MemoryBuffer *MemoryBuffer::getNewMemBuffer(size_t Size, StringRef BufferName) {
MemoryBuffer *SB = getNewUninitMemBuffer(Size, BufferName);
if (!SB) return 0;
- memset(const_cast<char*>(SB->getBufferStart()), 0, Size+1);
+ memset(const_cast<char*>(SB->getBufferStart()), 0, Size);
return SB;
}
@@ -158,18 +168,11 @@
/// MemoryBufferMMapFile - This represents a file that was mapped in with the
/// sys::Path::MapInFilePages method. When destroyed, it calls the
/// sys::Path::UnMapFilePages method.
-class MemoryBufferMMapFile : public MemoryBuffer {
- std::string Filename;
+class MemoryBufferMMapFile : public MemoryBufferMem {
public:
- MemoryBufferMMapFile(StringRef filename, const char *Pages, uint64_t Size)
- : Filename(filename) {
- init(Pages, Pages+Size);
- }
-
- virtual const char *getBufferIdentifier() const {
- return Filename.c_str();
- }
-
+ MemoryBufferMMapFile(StringRef Buffer)
+ : MemoryBufferMem(Buffer) { }
+
~MemoryBufferMMapFile() {
sys::Path::UnMapFilePages(getBufferStart(), getBufferSize());
}
@@ -227,8 +230,8 @@
if (FileSize >= 4096*4 &&
(FileSize & (sys::Process::GetPageSize()-1)) != 0) {
if (const char *Pages = sys::Path::MapInFilePages(FD, FileSize)) {
- // Close the file descriptor, now that the whole file is in memory.
- return new MemoryBufferMMapFile(Filename, Pages, FileSize);
+ return GetNamedBuffer<MemoryBufferMMapFile>(StringRef(Pages, FileSize),
+ Filename);
}
}
@@ -268,15 +271,6 @@
// MemoryBuffer::getSTDIN implementation.
//===----------------------------------------------------------------------===//
-namespace {
-class STDINBufferFile : public MemoryBuffer {
-public:
- virtual const char *getBufferIdentifier() const {
- return "<stdin>";
- }
-};
-}
-
MemoryBuffer *MemoryBuffer::getSTDIN(std::string *ErrStr) {
char Buffer[4096*4];
@@ -298,9 +292,5 @@
return 0;
}
- 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;
+ return getMemBufferCopy(StringRef(&FileData[0], FileData.size()), "<stdin>");
}
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