gecko-dev/js/public/ProfilingFrameIterator.h

82 lines
2.4 KiB
C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* vim: set ts=8 sts=4 et sw=4 tw=99:
* 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 http://mozilla.org/MPL/2.0/. */
#ifndef js_ProfilingFrameIterator_h
#define js_ProfilingFrameIterator_h
#include "mozilla/Alignment.h"
#include <stdint.h>
#include "js/Utility.h"
class JSAtom;
struct JSRuntime;
namespace js {
class Activation;
class AsmJSProfilingFrameIterator;
}
namespace JS {
// This iterator can be used to walk the stack of a thread suspended at an
// arbitrary pc. To provide acurate results, profiling must have been enabled
// (via EnableRuntimeProfilingStack) before executing the callstack being
// unwound.
class JS_PUBLIC_API(ProfilingFrameIterator)
{
js::Activation *activation_;
static const unsigned StorageSpace = 6 * sizeof(void*);
mozilla::AlignedStorage<StorageSpace> storage_;
js::AsmJSProfilingFrameIterator &asmJSIter() {
JS_ASSERT(!done());
return *reinterpret_cast<js::AsmJSProfilingFrameIterator*>(storage_.addr());
}
const js::AsmJSProfilingFrameIterator &asmJSIter() const {
JS_ASSERT(!done());
return *reinterpret_cast<const js::AsmJSProfilingFrameIterator*>(storage_.addr());
}
void settle();
public:
struct RegisterState
{
RegisterState() : pc(nullptr), sp(nullptr), lr(nullptr) {}
void *pc;
void *sp;
void *lr;
};
ProfilingFrameIterator(JSRuntime *rt, const RegisterState &state);
~ProfilingFrameIterator();
void operator++();
bool done() const { return !activation_; }
// Assuming the stack grows down (we do), the return value:
// - always points into the stack
// - is weakly monotonically increasing (may be equal for successive frames)
// - will compare greater than newer native and psuedo-stack frame addresses
// and less than older native and psuedo-stack frame addresses
void *stackAddress() const;
// Return a label suitable for regexp-matching as performed by
// browser/devtools/profiler/cleopatra/js/parserWorker.js
const char *label() const;
private:
void iteratorConstruct(const RegisterState &state);
void iteratorConstruct();
void iteratorDestroy();
bool iteratorDone();
};
} // namespace JS
#endif /* js_ProfilingFrameIterator_h */