js/src/vm/Probes.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
   2  * vim: set ts=8 sts=2 et sw=2 tw=80:
   3  * This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "vm/Probes-inl.h"
   8
   9 #ifdef INCLUDE_MOZILLA_DTRACE
  10 #  include "vm/JSScript-inl.h"
  11 #endif
  12
  13 using namespace js;
  14
  15 const char probes::nullName[] = "(null)";
  16 const char probes::anonymousName[] = "(anonymous)";
  17
  18 bool probes::ProfilingActive = true;
  19
  20 #ifdef INCLUDE_MOZILLA_DTRACE
  21 static const char* ScriptFilename(const JSScript* script) {
  22   if (!script) {
  23     return probes::nullName;
  24   }
  25   if (!script->filename()) {
  26     return probes::anonymousName;
  27   }
  28   return script->filename();
  29 }
  30
  31 static const char* FunctionName(JSContext* cx, JSFunction* fun,
  32                                 UniqueChars* bytes) {
  33   if (!fun) {
  34     return probes::nullName;
  35   }
  36   if (!fun->maybePartialDisplayAtom()) {
  37     return probes::anonymousName;
  38   }
  39   // TODO: Should be JS_EncodeStringToUTF8, but that'd introduce a rooting
  40   // hazard, because JS_EncodeStringToUTF8 can GC.
  41   *bytes = JS_EncodeStringToLatin1(cx, fun->maybePartialDisplayAtom());
  42   return *bytes ? bytes->get() : probes::nullName;
  43 }
  44
  45 /*
  46  * These functions call the DTrace macros for the JavaScript USDT probes.
  47  * Originally this code was inlined in the JavaScript code; however since
  48  * a number of operations are called, these have been placed into functions
  49  * to reduce any negative compiler optimization effect that the addition of
  50  * a number of usually unused lines of code would cause.
  51  */
  52 void probes::DTraceEnterJSFun(JSContext* cx, JSFunction* fun,
  53                               JSScript* script) {
  54   UniqueChars funNameBytes;
  55   JAVASCRIPT_FUNCTION_ENTRY(ScriptFilename(script), probes::nullName,
  56                             FunctionName(cx, fun, &funNameBytes));
  57 }
  58
  59 void probes::DTraceExitJSFun(JSContext* cx, JSFunction* fun, JSScript* script) {
  60   UniqueChars funNameBytes;
  61   JAVASCRIPT_FUNCTION_RETURN(ScriptFilename(script), probes::nullName,
  62                              FunctionName(cx, fun, &funNameBytes));
  63 }
  64 #endif