1/*
2 * Copyright (C) 2016 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#pragma once
27
28#include "DFGCommon.h"
29
30#if ENABLE(FTL_JIT)
31
32#include "CallFrame.h"
33#include "DFGNodeOrigin.h"
34#include "ExitKind.h"
35#include "HandlerInfo.h"
36#include <wtf/Ref.h>
37#include <wtf/ThreadSafeRefCounted.h>
38
39namespace JSC {
40
41namespace B3 {
42class StackmapGenerationParams;
43} // namespace B3
44
45namespace FTL {
46
47class ExceptionTarget;
48class State;
49struct OSRExitDescriptor;
50struct OSRExitHandle;
51
52class PatchpointExceptionHandle : public ThreadSafeRefCounted<PatchpointExceptionHandle> {
53public:
54 static Ref<PatchpointExceptionHandle> create(
55 State&, OSRExitDescriptor*, DFG::NodeOrigin, unsigned offset, const HandlerInfo&);
56
57 static RefPtr<PatchpointExceptionHandle> defaultHandle(State&);
58
59 ~PatchpointExceptionHandle();
60
61 // Note that you can use this handle to schedule any number of exits. This capability is here for
62 // two reasons:
63 //
64 // - B3 code duplication. B3 could take a patchpoint and turn it into multiple patchpoints if it
65 // duplicates code. Duplicating code is legal since you can do it without changing the behavior
66 // of the program. One example is tail duplication. Another is jump threading. Yet another is
67 // path specialization. You will have one PatchpointExceptionHandle per patchpoint you create
68 // during DFG->B3 lowering, and that patchpoint will have a generator that calls
69 // handle->scheduleBlah(). That generator will be called multiple times if your patchpoint got
70 // duplicated.
71 //
72 // - Combination of unwind and non-unwind exception handlers inside one patchpoint. A GetById may
73 // need both an exception handler that serves as an unwind target and an exception handler that
74 // is branched to directly for operation calls emitted inside the patchpoint. In that case,
75 // you'll call both scheduleExitCreation() and scheduleExitCreationForUnwind() on the same
76 // handle.
77
78 // Schedules the creation of an OSR exit jump destination. You don't know when this will be
79 // created, but it will happen before linking. You can link jumps to it during link time. That's
80 // why this returns an ExceptionTarget. That will contain the jump destination (target->label())
81 // at link time. This function should be used for exceptions from C calls.
82 RefPtr<ExceptionTarget> scheduleExitCreation(const B3::StackmapGenerationParams&);
83
84 // Schedules the creation of an OSR exit jump destination, and ensures that it gets associated
85 // with the handler for some callsite index. This function should be used for exceptions from JS.
86 void scheduleExitCreationForUnwind(const B3::StackmapGenerationParams&, CallSiteIndex);
87
88private:
89 PatchpointExceptionHandle(
90 State&, OSRExitDescriptor*, DFG::NodeOrigin, unsigned offset, const HandlerInfo&);
91
92 Ref<OSRExitHandle> createHandle(ExitKind, const B3::StackmapGenerationParams&);
93
94 State& m_state;
95 OSRExitDescriptor* m_descriptor;
96 DFG::NodeOrigin m_origin;
97 unsigned m_offset;
98 HandlerInfo m_handler;
99};
100
101} } // namespace JSC::FTL
102
103#endif // ENABLE(FTL_JIT)
104