Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 181 insertions, 0 deletions

diff --git a/gfx/angle/checkout/src/common/PoolAlloc.h b/gfx/angle/checkout/src/common/PoolAlloc.h
new file mode 100644
index 0000000000..536848f198
--- /dev/null
+++ b/gfx/angle/checkout/src/common/PoolAlloc.h
@@ -0,0 +1,181 @@
+//
+// 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.h:
+//    Defines the class interface for PoolAllocator.
+//
+
+#ifndef COMMON_POOLALLOC_H_
+#define COMMON_POOLALLOC_H_
+
+#if !defined(NDEBUG)
+#    define ANGLE_POOL_ALLOC_GUARD_BLOCKS  // define to enable guard block checking
+#endif
+
+//
+// This header defines an allocator that can be used to efficiently
+// allocate a large number of small requests for heap memory, with the
+// intention that they are not individually deallocated, but rather
+// collectively deallocated at one time.
+//
+// This simultaneously
+//
+// * Makes each individual allocation much more efficient; the
+//     typical allocation is trivial.
+// * Completely avoids the cost of doing individual deallocation.
+// * Saves the trouble of tracking down and plugging a large class of leaks.
+//
+// Individual classes can use this allocator by supplying their own
+// new and delete methods.
+//
+
+#include "angleutils.h"
+#include "common/debug.h"
+
+namespace angle
+{
+class Allocation;
+class PageHeader;
+
+//
+// There are several stacks.  One is to track the pushing and popping
+// of the user, and not yet implemented.  The others are simply a
+// repositories of free pages or used pages.
+//
+// Page stacks are linked together with a simple header at the beginning
+// of each allocation obtained from the underlying OS.  Multi-page allocations
+// are returned to the OS.  Individual page allocations are kept for future
+// re-use.
+//
+// The "page size" used is not, nor must it match, the underlying OS
+// page size.  But, having it be about that size or equal to a set of
+// pages is likely most optimal.
+//
+class PoolAllocator : angle::NonCopyable
+{
+  public:
+    static const int kDefaultAlignment = sizeof(void *);
+    //
+    // Create PoolAllocator. If alignment is set to 1 byte then fastAllocate()
+    //  function can be used to make allocations with less overhead.
+    //
+    PoolAllocator(int growthIncrement = 8 * 1024, int allocationAlignment = kDefaultAlignment);
+
+    //
+    // Don't call the destructor just to free up the memory, call pop()
+    //
+    ~PoolAllocator();
+
+    //
+    // Initialize page size and alignment after construction
+    //
+    void initialize(int pageSize, int alignment);
+
+    //
+    // Call push() to establish a new place to pop memory to.  Does not
+    // have to be called to get things started.
+    //
+    void push();
+
+    //
+    // Call pop() to free all memory allocated since the last call to push(),
+    // or if no last call to push, frees all memory since first allocation.
+    //
+    void pop();
+
+    //
+    // Call popAll() to free all memory allocated.
+    //
+    void popAll();
+
+    //
+    // Call allocate() to actually acquire memory.  Returns 0 if no memory
+    // available, otherwise a properly aligned pointer to 'numBytes' of memory.
+    //
+    void *allocate(size_t numBytes);
+
+    //
+    // Call fastAllocate() for a faster allocate function that does minimal bookkeeping
+    // preCondition: Allocator must have been created w/ alignment of 1
+    ANGLE_INLINE uint8_t *fastAllocate(size_t numBytes)
+    {
+#if defined(ANGLE_DISABLE_POOL_ALLOC)
+        return reinterpret_cast<uint8_t *>(allocate(numBytes));
+#else
+        ASSERT(mAlignment == 1);
+        // No multi-page allocations
+        ASSERT(numBytes <= (mPageSize - mPageHeaderSkip));
+        //
+        // Do the allocation, most likely case inline first, for efficiency.
+        //
+        if (numBytes <= mPageSize - mCurrentPageOffset)
+        {
+            //
+            // Safe to allocate from mCurrentPageOffset.
+            //
+            uint8_t *memory = reinterpret_cast<uint8_t *>(mInUseList) + mCurrentPageOffset;
+            mCurrentPageOffset += numBytes;
+            return memory;
+        }
+        return allocateNewPage(numBytes);
+#endif
+    }
+
+    // There is no deallocate.  The point of this class is that deallocation can be skipped by the
+    // user of it, as the model of use is to simultaneously deallocate everything at once by calling
+    // pop(), and to not have to solve memory leak problems.
+
+    // Catch unwanted allocations.
+    // TODO(jmadill): Remove this when we remove the global allocator.
+    void lock();
+    void unlock();
+
+  private:
+    size_t mAlignment;  // all returned allocations will be aligned at
+                        // this granularity, which will be a power of 2
+#if !defined(ANGLE_DISABLE_POOL_ALLOC)
+    struct AllocState
+    {
+        size_t offset;
+        PageHeader *page;
+    };
+    using AllocStack = std::vector<AllocState>;
+
+    // Slow path of allocation when we have to get a new page.
+    uint8_t *allocateNewPage(size_t numBytes);
+    // Track allocations if and only if we're using guard blocks
+    void *initializeAllocation(uint8_t *memory, size_t numBytes);
+
+    // Granularity of allocation from the OS
+    size_t mPageSize;
+    // Amount of memory to skip to make room for the page header (which is the size of the page
+    // header, or PageHeader in PoolAlloc.cpp)
+    size_t mPageHeaderSkip;
+    // Next offset in top of inUseList to allocate from.  This offset is not necessarily aligned to
+    // anything.  When an allocation is made, the data is aligned to mAlignment, and the header (if
+    // any) will align to pointer size by extension (since mAlignment is made aligned to at least
+    // pointer size).
+    size_t mCurrentPageOffset;
+    // List of popped memory
+    PageHeader *mFreeList;
+    // List of all memory currently being used.  The head of this list is where allocations are
+    // currently being made from.
+    PageHeader *mInUseList;
+    // Stack of where to allocate from, to partition pool
+    AllocStack mStack;
+
+    int mNumCalls;       // just an interesting statistic
+    size_t mTotalBytes;  // just an interesting statistic
+
+#else  // !defined(ANGLE_DISABLE_POOL_ALLOC)
+    std::vector<std::vector<void *>> mStack;
+#endif
+
+    bool mLocked;
+};
+
+}  // namespace angle
+
+#endif  // COMMON_POOLALLOC_H_