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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim: set ts=8 sts=2 et sw=2 tw=80:
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at */
#ifndef dbg_DebugScript_h
#define dbg_DebugScript_h
#include <stddef.h> // for offsetof
#include <stddef.h> // for size_t
#include <stdint.h> // for uint32_t
#include "jsapi.h"
#include "jstypes.h"
namespace JS {
class JS_PUBLIC_API Realm;
namespace js {
class JSBreakpointSite;
class Debugger;
// DebugScript manages the internal debugger state for a JSScript, which may be
// associated with multiple Debuggers.
class DebugScript {
friend class DebugAPI;
* If this is a generator script, this is the number of Debugger.Frames
* referring to calls to this generator, whether live or suspended. Closed
* generators do not contribute a count.
* When greater than zero, this script should be compiled with debug
* instrumentation to call Debugger::onResumeFrame at each resumption site, so
* that Debugger can reconnect any extant Debugger.Frames with the new
* concrete frame.
uint32_t generatorObserverCount;
* The number of Debugger.Frame objects that refer to frames running this
* script and that have onStep handlers. When nonzero, the interpreter and JIT
* must arrange to call Debugger::onSingleStep before each bytecode, or at
* least at some useful granularity.
uint32_t stepperCount;
* Number of breakpoint sites at opcodes in the script. This is the number
* of populated entries in DebugScript::breakpoints, below.
uint32_t numSites;
* Breakpoints set in our script. For speed and simplicity, this array is
* parallel to script->code(): the JSBreakpointSite for the opcode at
* script->code()[offset] is debugScript->breakpoints[offset]. Naturally,
* this array's true length is script->length().
JSBreakpointSite* breakpoints[1];
* True if this DebugScript carries any useful information. If false, it
* should be removed from its JSScript.
bool needed() const {
return generatorObserverCount > 0 || stepperCount > 0 || numSites > 0;
static size_t allocSize(size_t codeLength) {
return offsetof(DebugScript, breakpoints) +
codeLength * sizeof(JSBreakpointSite*);
void trace(JSTracer* trc, JSScript* owner);
void delete_(JSFreeOp* fop, JSScript* owner);
static DebugScript* get(JSScript* script);
static DebugScript* getOrCreate(JSContext* cx, JSScript* script);
static JSBreakpointSite* getBreakpointSite(JSScript* script, jsbytecode* pc);
static JSBreakpointSite* getOrCreateBreakpointSite(JSContext* cx,
JSScript* script,
jsbytecode* pc);
static void destroyBreakpointSite(JSFreeOp* fop, JSScript* script,
jsbytecode* pc);
static void clearBreakpointsIn(JSFreeOp* fop, JS::Realm* realm, Debugger* dbg,
JSObject* handler);
static void clearBreakpointsIn(JSFreeOp* fop, JSScript* script, Debugger* dbg,
JSObject* handler);
#ifdef DEBUG
static uint32_t getStepperCount(JSScript* script);
* Increment or decrement the single-step count. If the count is non-zero
* then the script is in single-step mode.
* Only incrementing is fallible, as it could allocate a DebugScript.
static MOZ_MUST_USE bool incrementStepperCount(JSContext* cx,
JSScript* script);
static void decrementStepperCount(JSFreeOp* fop, JSScript* script);
* Increment or decrement the generator observer count. If the count is
* non-zero then the script reports resumptions to the debugger.
* Only incrementing is fallible, as it could allocate a DebugScript.
static MOZ_MUST_USE bool incrementGeneratorObserverCount(JSContext* cx,
JSScript* script);
static void decrementGeneratorObserverCount(JSFreeOp* fop, JSScript* script);
} /* namespace js */
#endif /* dbg_DebugScript_h */