blob: 724e07e0668139d95446ddd7ab4209249e6e1542 [file] [log] [blame]
//
// Copyright 2019 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//
// PoolAlloc.cpp:
// Implements the class methods for PoolAllocator and Allocation classes.
//
#include "common/PoolAlloc.h"
#include <assert.h>
#include <stdint.h>
#include <stdio.h>
#include "common/angleutils.h"
#include "common/debug.h"
#include "common/mathutil.h"
#include "common/platform.h"
#include "common/tls.h"
namespace angle
{
//
// Implement the functionality of the PoolAllocator class, which
// is documented in PoolAlloc.h.
//
PoolAllocator::PoolAllocator(int growthIncrement, int allocationAlignment)
: mAlignment(allocationAlignment),
#if !defined(ANGLE_DISABLE_POOL_ALLOC)
mPageSize(growthIncrement),
mFreeList(0),
mInUseList(0),
mNumCalls(0),
mTotalBytes(0),
#endif
mLocked(false)
{
#if !defined(ANGLE_DISABLE_POOL_ALLOC)
if (mAlignment == 1)
{
// This is a special fast-path where fastAllocation() is enabled
mAlignmentMask = 0;
mHeaderSkip = sizeof(Header);
}
else
{
#endif
//
// Adjust mAlignment to be at least pointer aligned and
// power of 2.
//
size_t minAlign = sizeof(void *);
mAlignment &= ~(minAlign - 1);
if (mAlignment < minAlign)
mAlignment = minAlign;
mAlignment = gl::ceilPow2(static_cast<unsigned int>(mAlignment));
mAlignmentMask = mAlignment - 1;
#if !defined(ANGLE_DISABLE_POOL_ALLOC)
//
// Align header skip
//
mHeaderSkip = minAlign;
if (mHeaderSkip < sizeof(Header))
{
mHeaderSkip = rx::roundUpPow2(sizeof(Header), mAlignment);
}
}
//
// Don't allow page sizes we know are smaller than all common
// OS page sizes.
//
if (mPageSize < 4 * 1024)
mPageSize = 4 * 1024;
//
// A large mCurrentPageOffset indicates a new page needs to
// be obtained to allocate memory.
//
mCurrentPageOffset = mPageSize;
#else // !defined(ANGLE_DISABLE_POOL_ALLOC)
mStack.push_back({});
#endif
}
PoolAllocator::~PoolAllocator()
{
#if !defined(ANGLE_DISABLE_POOL_ALLOC)
while (mInUseList)
{
Header *next = mInUseList->nextPage;
mInUseList->~Header();
delete[] reinterpret_cast<char *>(mInUseList);
mInUseList = next;
}
// We should not check the guard blocks
// here, because we did it already when the block was
// placed into the free list.
//
while (mFreeList)
{
Header *next = mFreeList->nextPage;
delete[] reinterpret_cast<char *>(mFreeList);
mFreeList = next;
}
#else // !defined(ANGLE_DISABLE_POOL_ALLOC)
for (auto &allocs : mStack)
{
for (auto alloc : allocs)
{
free(alloc);
}
}
mStack.clear();
#endif
}
//
// Check a single guard block for damage
//
void Allocation::checkGuardBlock(unsigned char *blockMem,
unsigned char val,
const char *locText) const
{
#if defined(ANGLE_POOL_ALLOC_GUARD_BLOCKS)
for (size_t x = 0; x < kGuardBlockSize; x++)
{
if (blockMem[x] != val)
{
char assertMsg[80];
// We don't print the assert message. It's here just to be helpful.
snprintf(assertMsg, sizeof(assertMsg),
"PoolAlloc: Damage %s %zu byte allocation at 0x%p\n", locText, mSize, data());
assert(0 && "PoolAlloc: Damage in guard block");
}
}
#endif
}
void PoolAllocator::push()
{
#if !defined(ANGLE_DISABLE_POOL_ALLOC)
AllocState state = {mCurrentPageOffset, mInUseList};
mStack.push_back(state);
//
// Indicate there is no current page to allocate from.
//
mCurrentPageOffset = mPageSize;
#else // !defined(ANGLE_DISABLE_POOL_ALLOC)
mStack.push_back({});
#endif
}
//
// Do a mass-deallocation of all the individual allocations
// that have occurred since the last push(), or since the
// last pop(), or since the object's creation.
//
// The deallocated pages are saved for future allocations.
//
void PoolAllocator::pop()
{
if (mStack.size() < 1)
return;
#if !defined(ANGLE_DISABLE_POOL_ALLOC)
Header *page = mStack.back().page;
mCurrentPageOffset = mStack.back().offset;
while (mInUseList != page)
{
// invoke destructor to free allocation list
mInUseList->~Header();
Header *nextInUse = mInUseList->nextPage;
if (mInUseList->pageCount > 1)
delete[] reinterpret_cast<char *>(mInUseList);
else
{
mInUseList->nextPage = mFreeList;
mFreeList = mInUseList;
}
mInUseList = nextInUse;
}
mStack.pop_back();
#else // !defined(ANGLE_DISABLE_POOL_ALLOC)
for (auto &alloc : mStack.back())
{
free(alloc);
}
mStack.pop_back();
#endif
}
//
// Do a mass-deallocation of all the individual allocations
// that have occurred.
//
void PoolAllocator::popAll()
{
while (mStack.size() > 0)
pop();
}
void *PoolAllocator::allocate(size_t numBytes)
{
ASSERT(!mLocked);
#if !defined(ANGLE_DISABLE_POOL_ALLOC)
//
// Just keep some interesting statistics.
//
++mNumCalls;
mTotalBytes += numBytes;
// If we are using guard blocks, all allocations are bracketed by
// them: [guardblock][allocation][guardblock]. numBytes is how
// much memory the caller asked for. allocationSize is the total
// size including guard blocks. In release build,
// kGuardBlockSize=0 and this all gets optimized away.
size_t allocationSize = Allocation::AllocationSize(numBytes) + mAlignment;
// Detect integer overflow.
if (allocationSize < numBytes)
return 0;
//
// Do the allocation, most likely case first, for efficiency.
// This step could be moved to be inline sometime.
//
if (allocationSize <= mPageSize - mCurrentPageOffset)
{
//
// Safe to allocate from mCurrentPageOffset.
//
unsigned char *memory = reinterpret_cast<unsigned char *>(mInUseList) + mCurrentPageOffset;
mCurrentPageOffset += allocationSize;
mCurrentPageOffset = (mCurrentPageOffset + mAlignmentMask) & ~mAlignmentMask;
return initializeAllocation(mInUseList, memory, numBytes);
}
if (allocationSize > mPageSize - mHeaderSkip)
{
//
// Do a multi-page allocation. Don't mix these with the others.
// The OS is efficient in allocating and freeing multiple pages.
//
size_t numBytesToAlloc = allocationSize + mHeaderSkip;
// Detect integer overflow.
if (numBytesToAlloc < allocationSize)
return 0;
Header *memory = reinterpret_cast<Header *>(::new char[numBytesToAlloc]);
if (memory == 0)
return 0;
// Use placement-new to initialize header
new (memory) Header(mInUseList, (numBytesToAlloc + mPageSize - 1) / mPageSize);
mInUseList = memory;
mCurrentPageOffset = mPageSize; // make next allocation come from a new page
// No guard blocks for multi-page allocations (yet)
void *unalignedPtr =
reinterpret_cast<void *>(reinterpret_cast<uintptr_t>(memory) + mHeaderSkip);
return std::align(mAlignment, numBytes, unalignedPtr, allocationSize);
}
unsigned char *newPageAddr =
static_cast<unsigned char *>(allocateNewPage(numBytes, allocationSize));
return initializeAllocation(mInUseList, newPageAddr, numBytes);
#else // !defined(ANGLE_DISABLE_POOL_ALLOC)
void *alloc = malloc(numBytes + mAlignmentMask);
mStack.back().push_back(alloc);
intptr_t intAlloc = reinterpret_cast<intptr_t>(alloc);
intAlloc = (intAlloc + mAlignmentMask) & ~mAlignmentMask;
return reinterpret_cast<void *>(intAlloc);
#endif
}
#if !defined(ANGLE_DISABLE_POOL_ALLOC)
void *PoolAllocator::allocateNewPage(size_t numBytes, size_t allocationSize)
{
//
// Need a simple page to allocate from.
//
Header *memory;
if (mFreeList)
{
memory = mFreeList;
mFreeList = mFreeList->nextPage;
}
else
{
memory = reinterpret_cast<Header *>(::new char[mPageSize]);
if (memory == 0)
return 0;
}
// Use placement-new to initialize header
new (memory) Header(mInUseList, 1);
mInUseList = memory;
unsigned char *ret = reinterpret_cast<unsigned char *>(mInUseList) + mHeaderSkip;
mCurrentPageOffset = (mHeaderSkip + allocationSize + mAlignmentMask) & ~mAlignmentMask;
return ret;
}
#endif
void PoolAllocator::lock()
{
ASSERT(!mLocked);
mLocked = true;
}
void PoolAllocator::unlock()
{
ASSERT(mLocked);
mLocked = false;
}
//
// Check all allocations in a list for damage by calling check on each.
//
void Allocation::checkAllocList() const
{
for (const Allocation *alloc = this; alloc != 0; alloc = alloc->mPrevAlloc)
alloc->check();
}
} // namespace angle