forked from OSchip/llvm-project
115 lines
3.2 KiB
C++
115 lines
3.2 KiB
C++
//===-- xray_buffer_queue.cc -----------------------------------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file is a part of XRay, a dynamic runtime instruementation system.
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//
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// Defines the interface for a buffer queue implementation.
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//
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//===----------------------------------------------------------------------===//
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#include "xray_buffer_queue.h"
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#include "sanitizer_common/sanitizer_allocator_internal.h"
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#include "sanitizer_common/sanitizer_common.h"
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#include "sanitizer_common/sanitizer_libc.h"
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using namespace __xray;
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using namespace __sanitizer;
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BufferQueue::BufferQueue(size_t B, size_t N, bool &Success)
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: BufferSize(B), Buffers(new BufferRep[N]()), BufferCount(N), Finalizing{0},
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OwnedBuffers(new void *[N]()), Next(Buffers), First(Buffers),
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LiveBuffers(0) {
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for (size_t i = 0; i < N; ++i) {
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auto &T = Buffers[i];
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void *Tmp = InternalAlloc(BufferSize, nullptr, 64);
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if (Tmp == nullptr) {
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Success = false;
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return;
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}
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void *Extents = InternalAlloc(sizeof(BufferExtents), nullptr, 64);
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if (Extents == nullptr) {
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Success = false;
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return;
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}
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auto &Buf = T.Buff;
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Buf.Data = Tmp;
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Buf.Size = B;
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Buf.Extents = reinterpret_cast<BufferExtents *>(Extents);
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OwnedBuffers[i] = Tmp;
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}
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Success = true;
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}
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BufferQueue::ErrorCode BufferQueue::getBuffer(Buffer &Buf) {
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if (__sanitizer::atomic_load(&Finalizing, __sanitizer::memory_order_acquire))
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return ErrorCode::QueueFinalizing;
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__sanitizer::SpinMutexLock Guard(&Mutex);
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if (LiveBuffers == BufferCount)
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return ErrorCode::NotEnoughMemory;
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auto &T = *Next;
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auto &B = T.Buff;
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Buf = B;
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T.Used = true;
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++LiveBuffers;
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if (++Next == (Buffers + BufferCount))
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Next = Buffers;
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return ErrorCode::Ok;
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}
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BufferQueue::ErrorCode BufferQueue::releaseBuffer(Buffer &Buf) {
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// Blitz through the buffers array to find the buffer.
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bool Found = false;
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for (auto I = OwnedBuffers, E = OwnedBuffers + BufferCount; I != E; ++I) {
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if (*I == Buf.Data) {
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Found = true;
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break;
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}
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}
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if (!Found)
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return ErrorCode::UnrecognizedBuffer;
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__sanitizer::SpinMutexLock Guard(&Mutex);
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// This points to a semantic bug, we really ought to not be releasing more
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// buffers than we actually get.
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if (LiveBuffers == 0)
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return ErrorCode::NotEnoughMemory;
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// Now that the buffer has been released, we mark it as "used".
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First->Buff = Buf;
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First->Used = true;
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Buf.Data = nullptr;
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Buf.Size = 0;
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--LiveBuffers;
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if (++First == (Buffers + BufferCount))
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First = Buffers;
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return ErrorCode::Ok;
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}
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BufferQueue::ErrorCode BufferQueue::finalize() {
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if (__sanitizer::atomic_exchange(&Finalizing, 1,
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__sanitizer::memory_order_acq_rel))
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return ErrorCode::QueueFinalizing;
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return ErrorCode::Ok;
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}
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BufferQueue::~BufferQueue() {
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for (auto I = Buffers, E = Buffers + BufferCount; I != E; ++I) {
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auto &T = *I;
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auto &Buf = T.Buff;
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InternalFree(Buf.Data);
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InternalFree(Buf.Extents);
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}
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delete[] Buffers;
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delete[] OwnedBuffers;
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}
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