tools/CodeProfiling.cpp

   1 /*
   2  * Copyright (C) 2012 Apple Inc. All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  *
  13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
  14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
  17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #include "config.h"
  27 #include "CodeProfiling.h"
  28
  29 #include "CodeProfile.h"
  30 #include <wtf/MetaAllocator.h>
  31
  32 #if HAVE(SIGNAL_H)
  33 #include <signal.h>
  34 #endif
  35
  36 #if OS(LINUX)
  37 #include <sys/time.h>
  38 #endif
  39
  40 namespace JSC {
  41
  42 volatile CodeProfile* CodeProfiling::s_profileStack = 0;
  43 CodeProfiling::Mode CodeProfiling::s_mode = CodeProfiling::Disabled;
  44 WTF::MetaAllocatorTracker* CodeProfiling::s_tracker = 0;
  45
  46 #if COMPILER(CLANG)
  47 #pragma clang diagnostic push
  48 #pragma clang diagnostic ignored "-Wmissing-noreturn"
  49 #endif
  50
  51 #if (PLATFORM(MAC) && CPU(X86_64)) || (OS(LINUX) && CPU(X86))
  52 // Helper function to start & stop the timer.
  53 // Presently we're using the wall-clock timer, since this seems to give the best results.
  54 static void setProfileTimer(unsigned usec)
  55 {
  56     itimerval timer;
  57     timer.it_value.tv_sec = 0;
  58     timer.it_value.tv_usec = usec;
  59     timer.it_interval.tv_sec = 0;
  60     timer.it_interval.tv_usec = usec;
  61     setitimer(ITIMER_REAL, &timer, 0);
  62 }
  63 #endif
  64
  65 #if COMPILER(CLANG)
  66 #pragma clang diagnostic pop
  67 #endif
  68
  69 #if PLATFORM(MAC) && CPU(X86_64)
  70 static void profilingTimer(int, siginfo_t*, void* uap)
  71 {
  72     mcontext_t context = static_cast<ucontext_t*>(uap)->uc_mcontext;
  73     CodeProfiling::sample(reinterpret_cast<void*>(context->__ss.__rip),
  74                           reinterpret_cast<void**>(context->__ss.__rbp));
  75 }
  76 #elif OS(LINUX) && CPU(X86)
  77 static void profilingTimer(int, siginfo_t*, void* uap)
  78 {
  79     mcontext_t context = static_cast<ucontext_t*>(uap)->uc_mcontext;
  80     CodeProfiling::sample(reinterpret_cast<void*>(context.gregs[REG_EIP]),
  81                           reinterpret_cast<void**>(context.gregs[REG_EBP]));
  82 }
  83 #endif
  84
  85 // Callback triggered when the timer is fired.
  86 void CodeProfiling::sample(void* pc, void** framePointer)
  87 {
  88     CodeProfile* profileStack = const_cast<CodeProfile*>(s_profileStack);
  89     if (profileStack)
  90         profileStack->sample(pc, framePointer);
  91 }
  92
  93 void CodeProfiling::notifyAllocator(WTF::MetaAllocator* allocator)
  94 {
  95 #if !OS(WINCE)
  96     // Check for JSC_CODE_PROFILING.
  97     const char* codeProfilingMode = getenv("JSC_CODE_PROFILING");
  98     if (!codeProfilingMode)
  99         return;
 100
 101     // Check for a valid mode, currently "1", "2", or "3".
 102     if (!codeProfilingMode[0] || codeProfilingMode[1])
 103         return;
 104     switch (*codeProfilingMode) {
 105     case '1':
 106         s_mode = Enabled;
 107         break;
 108     case '2':
 109         s_mode = Verbose;
 110         break;
 111     case '3':
 112         s_mode = VeryVerbose;
 113         break;
 114     default:
 115         return;
 116     }
 117
 118     ASSERT(enabled());
 119     ASSERT(!s_tracker);
 120     s_tracker = new WTF::MetaAllocatorTracker();
 121     allocator->trackAllocations(s_tracker);
 122 #endif
 123 }
 124
 125 void* CodeProfiling::getOwnerUIDForPC(void* address)
 126 {
 127     if (!s_tracker)
 128         return 0;
 129     WTF::MetaAllocatorHandle* handle = s_tracker->find(address);
 130     if (!handle)
 131         return 0;
 132     return handle->ownerUID();
 133 }
 134
 135 void CodeProfiling::begin(const SourceCode& source)
 136 {
 137     // Push a new CodeProfile onto the stack for each script encountered.
 138     CodeProfile* profileStack = const_cast<CodeProfile*>(s_profileStack);
 139     bool alreadyProfiling = profileStack;
 140     s_profileStack = profileStack = new CodeProfile(source, profileStack);
 141
 142     // Is the profiler already running - if so, the timer will already be set up.
 143     if (alreadyProfiling)
 144         return;
 145
 146 #if (PLATFORM(MAC) && CPU(X86_64)) || (OS(LINUX) && CPU(X86))
 147     // Regsiter a signal handler & itimer.
 148     struct sigaction action;
 149     action.sa_sigaction = reinterpret_cast<void (*)(int, siginfo_t *, void *)>(profilingTimer);
 150     sigfillset(&action.sa_mask);
 151     action.sa_flags = SA_SIGINFO;
 152     sigaction(SIGALRM, &action, 0);
 153     setProfileTimer(100);
 154 #endif
 155 }
 156
 157 void CodeProfiling::end()
 158 {
 159     // Pop the current profiler off the stack.
 160     CodeProfile* current = const_cast<CodeProfile*>(s_profileStack);
 161     ASSERT(current);
 162     s_profileStack = current->parent();
 163
 164     // Is this the outermost script being profiled? - if not, just return.
 165     // We perform all output of profiles recursively from the outermost script,
 166     // to minimize profiling overhead from skewing results.
 167     if (s_profileStack)
 168         return;
 169
 170 #if (PLATFORM(MAC) && CPU(X86_64)) || (OS(LINUX) && CPU(X86))
 171     // Stop profiling
 172     setProfileTimer(0);
 173 #endif
 174
 175     current->report();
 176     delete current;
 177 }
 178
 179 }