darling-JavaScriptCore/ftl/FTLPatchpointExceptionHandle.h
2020-08-29 15:28:47 -04:00

104 lines
4.3 KiB
C++

/*
* Copyright (C) 2016 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include "DFGCommon.h"
#if ENABLE(FTL_JIT)
#include "CallFrame.h"
#include "DFGNodeOrigin.h"
#include "ExitKind.h"
#include "HandlerInfo.h"
#include <wtf/Ref.h>
#include <wtf/ThreadSafeRefCounted.h>
namespace JSC {
namespace B3 {
class StackmapGenerationParams;
} // namespace B3
namespace FTL {
class ExceptionTarget;
class State;
struct OSRExitDescriptor;
struct OSRExitHandle;
class PatchpointExceptionHandle : public ThreadSafeRefCounted<PatchpointExceptionHandle> {
public:
static Ref<PatchpointExceptionHandle> create(
State&, OSRExitDescriptor*, DFG::NodeOrigin, unsigned offset, const HandlerInfo&);
static RefPtr<PatchpointExceptionHandle> defaultHandle(State&);
~PatchpointExceptionHandle();
// Note that you can use this handle to schedule any number of exits. This capability is here for
// two reasons:
//
// - B3 code duplication. B3 could take a patchpoint and turn it into multiple patchpoints if it
// duplicates code. Duplicating code is legal since you can do it without changing the behavior
// of the program. One example is tail duplication. Another is jump threading. Yet another is
// path specialization. You will have one PatchpointExceptionHandle per patchpoint you create
// during DFG->B3 lowering, and that patchpoint will have a generator that calls
// handle->scheduleBlah(). That generator will be called multiple times if your patchpoint got
// duplicated.
//
// - Combination of unwind and non-unwind exception handlers inside one patchpoint. A GetById may
// need both an exception handler that serves as an unwind target and an exception handler that
// is branched to directly for operation calls emitted inside the patchpoint. In that case,
// you'll call both scheduleExitCreation() and scheduleExitCreationForUnwind() on the same
// handle.
// Schedules the creation of an OSR exit jump destination. You don't know when this will be
// created, but it will happen before linking. You can link jumps to it during link time. That's
// why this returns an ExceptionTarget. That will contain the jump destination (target->label())
// at link time. This function should be used for exceptions from C calls.
RefPtr<ExceptionTarget> scheduleExitCreation(const B3::StackmapGenerationParams&);
// Schedules the creation of an OSR exit jump destination, and ensures that it gets associated
// with the handler for some callsite index. This function should be used for exceptions from JS.
void scheduleExitCreationForUnwind(const B3::StackmapGenerationParams&, CallSiteIndex);
private:
PatchpointExceptionHandle(
State&, OSRExitDescriptor*, DFG::NodeOrigin, unsigned offset, const HandlerInfo&);
Ref<OSRExitHandle> createHandle(ExitKind, const B3::StackmapGenerationParams&);
State& m_state;
OSRExitDescriptor* m_descriptor;
DFG::NodeOrigin m_origin;
unsigned m_offset;
HandlerInfo m_handler;
};
} } // namespace JSC::FTL
#endif // ENABLE(FTL_JIT)