C++ LazyScript类代码示例

static void TraverseInnerLazyScriptsForLazyScript(
    JSContext* cx, void* data, LazyScript* enclosingLazyScript,
    IterateLazyScriptCallback lazyScriptCallback,
    const JS::AutoRequireNoGC& nogc) {
  GCPtrFunction* innerFunctions = enclosingLazyScript->innerFunctions();
  for (size_t i = 0, len = enclosingLazyScript->numInnerFunctions(); i < len;
       i++) {
    JSFunction* fun = innerFunctions[i];

    // LazyScript::CreateForXDR temporarily initializes innerFunctions with
    // its own function, but it should be overwritten with correct
    // inner functions before getting inserted into parent's innerFunctions.
    MOZ_ASSERT(fun != enclosingLazyScript->functionNonDelazifying());

    if (!fun->isInterpretedLazy()) {
      return;
    }

    LazyScript* lazyScript = fun->lazyScript();
    MOZ_ASSERT(lazyScript->hasEnclosingScope() ||
               lazyScript->hasEnclosingLazyScript());
    MOZ_ASSERT_IF(lazyScript->hasEnclosingLazyScript(),
                  lazyScript->enclosingLazyScript() == enclosingLazyScript);

    lazyScriptCallback(cx->runtime(), data, lazyScript, nogc);

    TraverseInnerLazyScriptsForLazyScript(cx, data, lazyScript,
                                          lazyScriptCallback, nogc);
  }
}

static bool
CreateLazyScriptsForCompartment(JSContext *cx)
{
    AutoObjectVector lazyFunctions(cx);

    // Find all root lazy functions in the compartment: those which have not been
    // compiled and which have a source object, indicating that their parent has
    // been compiled.
    for (gc::CellIter i(cx->zone(), JSFunction::FinalizeKind); !i.done(); i.next()) {
        JSObject *obj = i.get<JSObject>();
        if (obj->compartment() == cx->compartment() && obj->is<JSFunction>()) {
            JSFunction *fun = &obj->as<JSFunction>();
            if (fun->isInterpretedLazy()) {
                LazyScript *lazy = fun->lazyScriptOrNull();
                if (lazy && lazy->sourceObject() && !lazy->maybeScript()) {
                    if (!lazyFunctions.append(fun))
                        return false;
                }
            }
        }
    }

    // Create scripts for each lazy function, updating the list of functions to
    // process with any newly exposed inner functions in created scripts.
    // A function cannot be delazified until its outer script exists.
    for (size_t i = 0; i < lazyFunctions.length(); i++) {
        JSFunction *fun = &lazyFunctions[i]->as<JSFunction>();

        // lazyFunctions may have been populated with multiple functions for
        // a lazy script.
        if (!fun->isInterpretedLazy())
            continue;

        JSScript *script = fun->getOrCreateScript(cx);
        if (!script)
            return false;
        if (!AddInnerLazyFunctionsFromScript(script, lazyFunctions))
            return false;
    }

    // Repoint any clones of the original functions to their new script.
    for (gc::CellIter i(cx->zone(), JSFunction::FinalizeKind); !i.done(); i.next()) {
        JSObject *obj = i.get<JSObject>();
        if (obj->compartment() == cx->compartment() && obj->is<JSFunction>()) {
            JSFunction *fun = &obj->as<JSFunction>();
            if (fun->isInterpretedLazy()) {
                LazyScript *lazy = fun->lazyScriptOrNull();
                if (lazy && lazy->maybeScript())
                    fun->existingScript();
            }
        }
    }

    return true;
}

static bool
CreateLazyScriptsForCompartment(JSContext *cx)
{
    AutoObjectVector lazyFunctions(cx);

    // Find all live lazy scripts in the compartment, and via them all root
    // lazy functions in the compartment: those which have not been compiled,
    // which have a source object, indicating that they have a parent, and
    // which do not have an uncompiled enclosing script. The last condition is
    // so that we don't compile lazy scripts whose enclosing scripts failed to
    // compile, indicating that the lazy script did not escape the script.
    for (gc::ZoneCellIter i(cx->zone(), gc::FINALIZE_LAZY_SCRIPT); !i.done(); i.next()) {
        LazyScript *lazy = i.get<LazyScript>();
        JSFunction *fun = lazy->functionNonDelazifying();
        if (fun->compartment() == cx->compartment() &&
            lazy->sourceObject() && !lazy->maybeScript() &&
            !lazy->hasUncompiledEnclosingScript())
        {
            MOZ_ASSERT(fun->isInterpretedLazy());
            MOZ_ASSERT(lazy == fun->lazyScriptOrNull());
            if (!lazyFunctions.append(fun))
                return false;
        }
    }

    // Create scripts for each lazy function, updating the list of functions to
    // process with any newly exposed inner functions in created scripts.
    // A function cannot be delazified until its outer script exists.
    for (size_t i = 0; i < lazyFunctions.length(); i++) {
        JSFunction *fun = &lazyFunctions[i]->as<JSFunction>();

        // lazyFunctions may have been populated with multiple functions for
        // a lazy script.
        if (!fun->isInterpretedLazy())
            continue;

        JSScript *script = fun->getOrCreateScript(cx);
        if (!script)
            return false;
        if (!AddInnerLazyFunctionsFromScript(script, lazyFunctions))
            return false;
    }

    return true;
}

static bool
AddLazyFunctionsForCompartment(JSContext* cx, AutoObjectVector& lazyFunctions, AllocKind kind)
{
    // Find all live root lazy functions in the compartment: those which have a
    // source object, indicating that they have a parent, and which do not have
    // an uncompiled enclosing script. The last condition is so that we don't
    // compile lazy scripts whose enclosing scripts failed to compile,
    // indicating that the lazy script did not escape the script.
    //
    // Some LazyScripts have a non-null |JSScript* script| pointer. We still
    // want to delazify in that case: this pointer is weak so the JSScript
    // could be destroyed at the next GC.

    for (auto i = cx->zone()->cellIter<JSObject>(kind); !i.done(); i.next()) {
        JSFunction* fun = &i->as<JSFunction>();

        // Sweeping is incremental; take care to not delazify functions that
        // are about to be finalized. GC things referenced by objects that are
        // about to be finalized (e.g., in slots) may already be freed.
        if (gc::IsAboutToBeFinalizedUnbarriered(&fun) ||
            fun->compartment() != cx->compartment())
        {
            continue;
        }

        if (fun->isInterpretedLazy()) {
            LazyScript* lazy = fun->lazyScriptOrNull();
            if (lazy && lazy->sourceObject() && !lazy->hasUncompiledEnclosingScript()) {
                if (!lazyFunctions.append(fun))
                    return false;
            }
        }
    }

    return true;
}

static bool
CreateLazyScriptsForCompartment(JSContext* cx)
{
    AutoObjectVector lazyFunctions(cx);

    if (!AddLazyFunctionsForCompartment(cx, lazyFunctions, AllocKind::FUNCTION))
        return false;

    // Methods, for instance {get method() {}}, are extended functions that can
    // be relazified, so we need to handle those as well.
    if (!AddLazyFunctionsForCompartment(cx, lazyFunctions, AllocKind::FUNCTION_EXTENDED))
        return false;

    // Create scripts for each lazy function, updating the list of functions to
    // process with any newly exposed inner functions in created scripts.
    // A function cannot be delazified until its outer script exists.
    for (size_t i = 0; i < lazyFunctions.length(); i++) {
        JSFunction* fun = &lazyFunctions[i]->as<JSFunction>();

        // lazyFunctions may have been populated with multiple functions for
        // a lazy script.
        if (!fun->isInterpretedLazy())
            continue;

        LazyScript* lazy = fun->lazyScript();
        bool lazyScriptHadNoScript = !lazy->maybeScript();

        JSScript* script = fun->getOrCreateScript(cx);
        if (!script)
            return false;
        if (lazyScriptHadNoScript && !AddInnerLazyFunctionsFromScript(script, lazyFunctions))
            return false;
    }

    return true;
}

static bool
AddLazyFunctionsForCompartment(JSContext* cx, AutoObjectVector& lazyFunctions, AllocKind kind)
{
    // Find all live root lazy functions in the compartment: those which
    // have not been compiled, which have a source object, indicating that
    // they have a parent, and which do not have an uncompiled enclosing
    // script. The last condition is so that we don't compile lazy scripts
    // whose enclosing scripts failed to compile, indicating that the lazy
    // script did not escape the script.
    for (gc::ZoneCellIter i(cx->zone(), kind); !i.done(); i.next()) {
        JSObject* obj = i.get<JSObject>();

        // Sweeping is incremental; take care to not delazify functions that
        // are about to be finalized. GC things referenced by objects that are
        // about to be finalized (e.g., in slots) may already be freed.
        if (gc::IsObjectAboutToBeFinalized(&obj) ||
            obj->compartment() != cx->compartment() ||
            !obj->is<JSFunction>())
        {
            continue;
        }

        JSFunction* fun = &obj->as<JSFunction>();
        if (fun->isInterpretedLazy()) {
            LazyScript* lazy = fun->lazyScriptOrNull();
            if (lazy && lazy->sourceObject() && !lazy->maybeScript() &&
                !lazy->hasUncompiledEnclosingScript())
            {
                if (!lazyFunctions.append(fun))
                    return false;
            }
        }
    }

    return true;
}

static bool
CreateLazyScriptsForCompartment(JSContext* cx)
{
    AutoObjectVector lazyFunctions(cx);

    // Find all live root lazy functions in the compartment: those which
    // have not been compiled, which have a source object, indicating that
    // they have a parent, and which do not have an uncompiled enclosing
    // script. The last condition is so that we don't compile lazy scripts
    // whose enclosing scripts failed to compile, indicating that the lazy
    // script did not escape the script.
    //
    // Note that while we ideally iterate over LazyScripts, LazyScripts do not
    // currently stand in 1-1 relation with JSScripts; JSFunctions with the
    // same LazyScript may create different JSScripts due to relazification of
    // clones. See bug 1105306.
    for (gc::ZoneCellIter i(cx->zone(), JSFunction::FinalizeKind); !i.done(); i.next()) {
        JSObject* obj = i.get<JSObject>();
        if (obj->compartment() == cx->compartment() && obj->is<JSFunction>()) {
            JSFunction* fun = &obj->as<JSFunction>();
            if (fun->isInterpretedLazy()) {
                LazyScript* lazy = fun->lazyScriptOrNull();
                if (lazy && lazy->sourceObject() && !lazy->maybeScript() &&
                    !lazy->hasUncompiledEnclosingScript())
                {
                    if (!lazyFunctions.append(fun))
                        return false;
                }
            }
        }
    }

    // Create scripts for each lazy function, updating the list of functions to
    // process with any newly exposed inner functions in created scripts.
    // A function cannot be delazified until its outer script exists.
    for (size_t i = 0; i < lazyFunctions.length(); i++) {
        JSFunction* fun = &lazyFunctions[i]->as<JSFunction>();

        // lazyFunctions may have been populated with multiple functions for
        // a lazy script.
        if (!fun->isInterpretedLazy())
            continue;

        LazyScript* lazy = fun->lazyScript();
        bool lazyScriptHadNoScript = !lazy->maybeScript();

        JSScript* script = fun->getOrCreateScript(cx);
        if (!script)
            return false;
        if (lazyScriptHadNoScript && !AddInnerLazyFunctionsFromScript(script, lazyFunctions))
            return false;
    }

    return true;
}

//.........这里部分代码省略.........
        JSString *str = static_cast<JSString *>(thing);

        size_t strSize = str->sizeOfExcludingThis(rtStats->mallocSizeOf_);

        // If we can't grow hugeStrings, let's just call this string non-huge.
        // We're probably about to OOM anyway.
        if (strSize >= JS::HugeStringInfo::MinSize() && zStats->hugeStrings.growBy(1)) {
            zStats->gcHeapStringsNormal += thingSize;
            JS::HugeStringInfo &info = zStats->hugeStrings.back();
            info.length = str->length();
            info.size = strSize;
            PutEscapedString(info.buffer, sizeof(info.buffer), &str->asLinear(), 0);
        } else if (str->isShort()) {
            MOZ_ASSERT(strSize == 0);
            zStats->gcHeapStringsShort += thingSize;
        } else {
            zStats->gcHeapStringsNormal += thingSize;
            zStats->stringCharsNonHuge += strSize;
        }
        break;
      }

      case JSTRACE_SHAPE: {
        Shape *shape = static_cast<Shape *>(thing);
        CompartmentStats *cStats = GetCompartmentStats(shape->compartment());
        size_t propTableSize, kidsSize;
        shape->sizeOfExcludingThis(rtStats->mallocSizeOf_, &propTableSize, &kidsSize);
        if (shape->inDictionary()) {
            cStats->gcHeapShapesDict += thingSize;
            cStats->shapesExtraDictTables += propTableSize;
            JS_ASSERT(kidsSize == 0);
        } else {
            if (shape->base()->getObjectParent() == shape->compartment()->maybeGlobal()) {
                cStats->gcHeapShapesTreeGlobalParented += thingSize;
            } else {
                cStats->gcHeapShapesTreeNonGlobalParented += thingSize;
            }
            cStats->shapesExtraTreeTables += propTableSize;
            cStats->shapesExtraTreeShapeKids += kidsSize;
        }
        break;
      }

      case JSTRACE_BASE_SHAPE: {
        BaseShape *base = static_cast<BaseShape *>(thing);
        CompartmentStats *cStats = GetCompartmentStats(base->compartment());
        cStats->gcHeapShapesBase += thingSize;
        break;
      }

      case JSTRACE_SCRIPT: {
        JSScript *script = static_cast<JSScript *>(thing);
        CompartmentStats *cStats = GetCompartmentStats(script->compartment());
        cStats->gcHeapScripts += thingSize;
        cStats->scriptData += script->sizeOfData(rtStats->mallocSizeOf_);
#ifdef JS_ION
        size_t baselineData = 0, baselineStubsFallback = 0;
        ion::SizeOfBaselineData(script, rtStats->mallocSizeOf_, &baselineData,
                                &baselineStubsFallback);
        cStats->baselineData += baselineData;
        cStats->baselineStubsFallback += baselineStubsFallback;
        cStats->ionData += ion::SizeOfIonData(script, rtStats->mallocSizeOf_);
#endif

        ScriptSource *ss = script->scriptSource();
        SourceSet::AddPtr entry = closure->seenSources.lookupForAdd(ss);
        if (!entry) {
            closure->seenSources.add(entry, ss); // Not much to be done on failure.
            rtStats->runtime.scriptSources += ss->sizeOfIncludingThis(rtStats->mallocSizeOf_);
        }
        break;
      }

      case JSTRACE_LAZY_SCRIPT: {
        LazyScript *lazy = static_cast<LazyScript *>(thing);
        zStats->gcHeapLazyScripts += thingSize;
        zStats->lazyScripts += lazy->sizeOfExcludingThis(rtStats->mallocSizeOf_);
        break;
      }

      case JSTRACE_IONCODE: {
#ifdef JS_ION
        zStats->gcHeapIonCodes += thingSize;
        // The code for a script is counted in ExecutableAllocator::sizeOfCode().
#endif
        break;
      }

      case JSTRACE_TYPE_OBJECT: {
        types::TypeObject *obj = static_cast<types::TypeObject *>(thing);
        zStats->gcHeapTypeObjects += thingSize;
        zStats->typeObjects += obj->sizeOfExcludingThis(rtStats->mallocSizeOf_);
        break;
      }

    }

    // Yes, this is a subtraction:  see StatsArenaCallback() for details.
    zStats->gcHeapUnusedGcThings -= thingSize;
}

JS_PUBLIC_API void JS_GetTraceThingInfo(char* buf, size_t bufsize,
                                        JSTracer* trc, void* thing,
                                        JS::TraceKind kind, bool details) {
  const char* name = nullptr; /* silence uninitialized warning */
  size_t n;

  if (bufsize == 0) {
    return;
  }

  switch (kind) {
    case JS::TraceKind::BaseShape:
      name = "base_shape";
      break;

    case JS::TraceKind::JitCode:
      name = "jitcode";
      break;

    case JS::TraceKind::LazyScript:
      name = "lazyscript";
      break;

    case JS::TraceKind::Null:
      name = "null_pointer";
      break;

    case JS::TraceKind::Object: {
      name = static_cast<JSObject*>(thing)->getClass()->name;
      break;
    }

    case JS::TraceKind::ObjectGroup:
      name = "object_group";
      break;

    case JS::TraceKind::RegExpShared:
      name = "reg_exp_shared";
      break;

    case JS::TraceKind::Scope:
      name = "scope";
      break;

    case JS::TraceKind::Script:
      name = "script";
      break;

    case JS::TraceKind::Shape:
      name = "shape";
      break;

    case JS::TraceKind::String:
      name = ((JSString*)thing)->isDependent() ? "substring" : "string";
      break;

    case JS::TraceKind::Symbol:
      name = "symbol";
      break;

#ifdef ENABLE_BIGINT
    case JS::TraceKind::BigInt:
      name = "BigInt";
      break;
#endif

    default:
      name = "INVALID";
      break;
  }

  n = strlen(name);
  if (n > bufsize - 1) {
    n = bufsize - 1;
  }
  js_memcpy(buf, name, n + 1);
  buf += n;
  bufsize -= n;
  *buf = '\0';

  if (details && bufsize > 2) {
    switch (kind) {
      case JS::TraceKind::Object: {
        JSObject* obj = (JSObject*)thing;
        if (obj->is<JSFunction>()) {
          JSFunction* fun = &obj->as<JSFunction>();
          if (fun->displayAtom()) {
            *buf++ = ' ';
            bufsize--;
            PutEscapedString(buf, bufsize, fun->displayAtom(), 0);
          }
        } else if (obj->getClass()->flags & JSCLASS_HAS_PRIVATE) {
          snprintf(buf, bufsize, " %p", obj->as<NativeObject>().getPrivate());
        } else {
          snprintf(buf, bufsize, " <no private>");
        }
        break;
      }

      case JS::TraceKind::Script: {
//.........这里部分代码省略.........