OProfileWrapper.cpp revision dd778b230e60092be1553461f68fa8ec37c5fdc0 
1//===-- OProfileWrapper.cpp - OProfile JIT API Wrapper implementation -----===//
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 implements the interface in OProfileWrapper.h. It is responsible
11// for loading the opagent dynamic library when the first call to an op_
12// function occurs.
13//
14//===----------------------------------------------------------------------===//
15
16#define DEBUG_TYPE "oprofile-wrapper"
17#include "llvm/ExecutionEngine/OProfileWrapper.h"
18#include "llvm/Support/Debug.h"
19#include "llvm/Support/raw_ostream.h"
20#include "llvm/Support/DynamicLibrary.h"
21#include "llvm/Support/Mutex.h"
22#include "llvm/Support/MutexGuard.h"
23#include "llvm/ADT/SmallString.h"
24#include <cstring>
25#include <dirent.h>
26#include <fcntl.h>
27#include <sstream>
28#include <stddef.h>
29#include <sys/stat.h>
30#include <unistd.h>
31
32namespace {
33
34// Global mutex to ensure a single thread initializes oprofile agent.
35llvm::sys::Mutex OProfileInitializationMutex;
36
37} // anonymous namespace
38
39namespace llvm {
40
41OProfileWrapper::OProfileWrapper()
42: Agent(0),
43  OpenAgentFunc(0),
44  CloseAgentFunc(0),
45  WriteNativeCodeFunc(0),
46  WriteDebugLineInfoFunc(0),
47  UnloadNativeCodeFunc(0),
48  MajorVersionFunc(0),
49  MinorVersionFunc(0),
50  IsOProfileRunningFunc(0),
51  Initialized(false) {
52}
53
54bool OProfileWrapper::initialize() {
55  using namespace llvm;
56  using namespace llvm::sys;
57
58  MutexGuard Guard(OProfileInitializationMutex);
59
60  if (Initialized)
61    return OpenAgentFunc != 0;
62
63  Initialized = true;
64
65  // If the oprofile daemon is not running, don't load the opagent library
66  if (!isOProfileRunning()) {
67    DEBUG(dbgs() << "OProfile daemon is not detected.\n");
68    return false;
69  }
70
71  std::string error;
72  if(!DynamicLibrary::LoadLibraryPermanently("libopagent.so", &error)) {
73    DEBUG(dbgs()
74            << "OProfile connector library libopagent.so could not be loaded: "
75            << error << "\n");
76  }
77
78  // Get the addresses of the opagent functions
79  OpenAgentFunc = (op_open_agent_ptr_t)(intptr_t)
80          DynamicLibrary::SearchForAddressOfSymbol("op_open_agent");
81  CloseAgentFunc = (op_close_agent_ptr_t)(intptr_t)
82          DynamicLibrary::SearchForAddressOfSymbol("op_close_agent");
83  WriteNativeCodeFunc = (op_write_native_code_ptr_t)(intptr_t)
84          DynamicLibrary::SearchForAddressOfSymbol("op_write_native_code");
85  WriteDebugLineInfoFunc = (op_write_debug_line_info_ptr_t)(intptr_t)
86          DynamicLibrary::SearchForAddressOfSymbol("op_write_debug_line_info");
87  UnloadNativeCodeFunc = (op_unload_native_code_ptr_t)(intptr_t)
88          DynamicLibrary::SearchForAddressOfSymbol("op_unload_native_code");
89  MajorVersionFunc = (op_major_version_ptr_t)(intptr_t)
90          DynamicLibrary::SearchForAddressOfSymbol("op_major_version");
91  MinorVersionFunc = (op_major_version_ptr_t)(intptr_t)
92          DynamicLibrary::SearchForAddressOfSymbol("op_minor_version");
93
94  // With missing functions, we can do nothing
95  if (!OpenAgentFunc
96      || !CloseAgentFunc
97      || !WriteNativeCodeFunc
98      || !WriteDebugLineInfoFunc
99      || !UnloadNativeCodeFunc) {
100    OpenAgentFunc = 0;
101    CloseAgentFunc = 0;
102    WriteNativeCodeFunc = 0;
103    WriteDebugLineInfoFunc = 0;
104    UnloadNativeCodeFunc = 0;
105    return false;
106  }
107
108  return true;
109}
110
111bool OProfileWrapper::isOProfileRunning() {
112  if (IsOProfileRunningFunc != 0)
113    return IsOProfileRunningFunc();
114  return checkForOProfileProcEntry();
115}
116
117bool OProfileWrapper::checkForOProfileProcEntry() {
118  DIR* ProcDir;
119
120  ProcDir = opendir("/proc");
121  if (!ProcDir)
122    return false;
123
124  // Walk the /proc tree looking for the oprofile daemon
125  struct dirent* Entry;
126  while (0 != (Entry = readdir(ProcDir))) {
127    if (Entry->d_type == DT_DIR) {
128      // Build a path from the current entry name
129      SmallString<256> CmdLineFName;
130      raw_svector_ostream(CmdLineFName) << "/proc/" << Entry->d_name
131                                        << "/cmdline";
132
133      // Open the cmdline file
134      int CmdLineFD = open(CmdLineFName.c_str(), S_IRUSR);
135      if (CmdLineFD != -1) {
136        char    ExeName[PATH_MAX+1];
137        char*   BaseName = 0;
138
139        // Read the cmdline file
140        ssize_t NumRead = read(CmdLineFD, ExeName, PATH_MAX+1);
141        close(CmdLineFD);
142        ssize_t Idx = 0;
143
144        // Find the terminator for the first string
145        while (Idx < NumRead-1 && ExeName[Idx] != 0) {
146          Idx++;
147        }
148
149        // Go back to the last non-null character
150        Idx--;
151
152        // Find the last path separator in the first string
153        while (Idx > 0) {
154          if (ExeName[Idx] == '/') {
155            BaseName = ExeName + Idx + 1;
156            break;
157          }
158          Idx--;
159        }
160
161        // Test this to see if it is the oprofile daemon
162        if (BaseName != 0 && !strcmp("oprofiled", BaseName)) {
163          // If it is, we're done
164          closedir(ProcDir);
165          return true;
166        }
167      }
168    }
169  }
170
171  // We've looked through all the files and didn't find the daemon
172  closedir(ProcDir);
173  return false;
174}
175
176bool OProfileWrapper::op_open_agent() {
177  if (!Initialized)
178    initialize();
179
180  if (OpenAgentFunc != 0) {
181    Agent = OpenAgentFunc();
182    return Agent != 0;
183  }
184
185  return false;
186}
187
188int OProfileWrapper::op_close_agent() {
189  if (!Initialized)
190    initialize();
191
192  int ret = -1;
193  if (Agent && CloseAgentFunc) {
194    ret = CloseAgentFunc(Agent);
195    if (ret == 0) {
196      Agent = 0;
197    }
198  }
199  return ret;
200}
201
202bool OProfileWrapper::isAgentAvailable() {
203  return Agent != 0;
204}
205
206int OProfileWrapper::op_write_native_code(const char* Name,
207                                          uint64_t Addr,
208                                          void const* Code,
209                                          const unsigned int Size) {
210  if (!Initialized)
211    initialize();
212
213  if (Agent && WriteNativeCodeFunc)
214    return WriteNativeCodeFunc(Agent, Name, Addr, Code, Size);
215
216  return -1;
217}
218
219int OProfileWrapper::op_write_debug_line_info(
220  void const* Code,
221  size_t NumEntries,
222  struct debug_line_info const* Info) {
223  if (!Initialized)
224    initialize();
225
226  if (Agent && WriteDebugLineInfoFunc)
227    return WriteDebugLineInfoFunc(Agent, Code, NumEntries, Info);
228
229  return -1;
230}
231
232int OProfileWrapper::op_major_version() {
233  if (!Initialized)
234    initialize();
235
236  if (Agent && MajorVersionFunc)
237    return MajorVersionFunc();
238
239  return -1;
240}
241
242int OProfileWrapper::op_minor_version() {
243  if (!Initialized)
244    initialize();
245
246  if (Agent && MinorVersionFunc)
247    return MinorVersionFunc();
248
249  return -1;
250}
251
252int  OProfileWrapper::op_unload_native_code(uint64_t Addr) {
253  if (!Initialized)
254    initialize();
255
256  if (Agent && UnloadNativeCodeFunc)
257    return UnloadNativeCodeFunc(Agent, Addr);
258
259  return -1;
260}
261
262} // namespace llvm
263