1 //===-- xray_buffer_queue.cc -----------------------------------*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file is a part of XRay, a dynamic runtime instruementation system. 11 // 12 // Defines the interface for a buffer queue implementation. 13 // 14 //===----------------------------------------------------------------------===// 15 #include "xray_buffer_queue.h" 16 #include <cassert> 17 #include <cstdlib> 18 19 using namespace __xray; 20 21 BufferQueue::BufferQueue(std::size_t B, std::size_t N) 22 : BufferSize(B), Buffers(N), Mutex(), OwnedBuffers(), Finalizing(false) { 23 for (auto &Buf : Buffers) { 24 void *Tmp = malloc(BufferSize); 25 Buf.Buffer = Tmp; 26 Buf.Size = B; 27 if (Tmp != 0) 28 OwnedBuffers.insert(Tmp); 29 } 30 } 31 32 std::error_code BufferQueue::getBuffer(Buffer &Buf) { 33 if (Finalizing.load(std::memory_order_acquire)) 34 return std::make_error_code(std::errc::state_not_recoverable); 35 std::lock_guard<std::mutex> Guard(Mutex); 36 if (Buffers.empty()) 37 return std::make_error_code(std::errc::not_enough_memory); 38 Buf = Buffers.front(); 39 Buffers.pop_front(); 40 return {}; 41 } 42 43 std::error_code BufferQueue::releaseBuffer(Buffer &Buf) { 44 if (OwnedBuffers.count(Buf.Buffer) == 0) 45 return std::make_error_code(std::errc::argument_out_of_domain); 46 std::lock_guard<std::mutex> Guard(Mutex); 47 Buffers.push_back(Buf); 48 Buf.Buffer = nullptr; 49 Buf.Size = BufferSize; 50 return {}; 51 } 52 53 std::error_code BufferQueue::finalize() { 54 if (Finalizing.exchange(true, std::memory_order_acq_rel)) 55 return std::make_error_code(std::errc::state_not_recoverable); 56 return {}; 57 } 58 59 BufferQueue::~BufferQueue() { 60 for (auto &Buf : Buffers) { 61 free(Buf.Buffer); 62 Buf.Buffer = nullptr; 63 Buf.Size = 0; 64 } 65 } 66