The Tor Browser: js/src/jit/arm/Bailouts-arm.cpp@6474c204b198

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

     1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-

     2  * vim: set ts=8 sts=4 et sw=4 tw=99:

     3  * This Source Code Form is subject to the terms of the Mozilla Public

     4  * License, v. 2.0. If a copy of the MPL was not distributed with this

     5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

     7 #include "jscntxt.h"

     8 #include "jscompartment.h"

    10 #include "jit/Bailouts.h"

    11 #include "jit/JitCompartment.h"

    13 using namespace js;

    14 using namespace js::jit;

    16 namespace js {

    17 namespace jit {

    19 class BailoutStack

    20 {

    21     uintptr_t frameClassId_;

    22     // This is pushed in the bailout handler.  Both entry points into the handler

    23     // inserts their own value int lr, which is then placed onto the stack along

    24     // with frameClassId_ above.  This should be migrated to ip.

    25   public:

    26     union {

    27         uintptr_t frameSize_;

    28         uintptr_t tableOffset_;

    29     };

    31   protected: // Silence Clang warning about unused private fields.

    32     mozilla::Array<double, FloatRegisters::Total> fpregs_;

    33     mozilla::Array<uintptr_t, Registers::Total> regs_;

    35     uintptr_t snapshotOffset_;

    36     uintptr_t padding_;

    38   public:

    39     FrameSizeClass frameClass() const {

    40         return FrameSizeClass::FromClass(frameClassId_);

    41     }

    42     uintptr_t tableOffset() const {

    43         JS_ASSERT(frameClass() != FrameSizeClass::None());

    44         return tableOffset_;

    45     }

    46     uint32_t frameSize() const {

    47         if (frameClass() == FrameSizeClass::None())

    48             return frameSize_;

    49         return frameClass().frameSize();

    50     }

    51     MachineState machine() {

    52         return MachineState::FromBailout(regs_, fpregs_);

    53     }

    54     SnapshotOffset snapshotOffset() const {

    55         JS_ASSERT(frameClass() == FrameSizeClass::None());

    56         return snapshotOffset_;

    57     }

    58     uint8_t *parentStackPointer() const {

    59         if (frameClass() == FrameSizeClass::None())

    60             return (uint8_t *)this + sizeof(BailoutStack);

    61         return (uint8_t *)this + offsetof(BailoutStack, snapshotOffset_);

    62     }

    63 };

    65 // Make sure the compiler doesn't add extra padding.

    66 static_assert((sizeof(BailoutStack) % 8) == 0, "BailoutStack should be 8-byte aligned.");

    68 } // namespace jit

    69 } // namespace js

    71 IonBailoutIterator::IonBailoutIterator(const JitActivationIterator &activations,

    72                                        BailoutStack *bailout)

    73   : JitFrameIterator(activations),

    74     machine_(bailout->machine())

    75 {

    76     uint8_t *sp = bailout->parentStackPointer();

    77     uint8_t *fp = sp + bailout->frameSize();

    79     current_ = fp;

    80     type_ = JitFrame_IonJS;

    81     topFrameSize_ = current_ - sp;

    82     topIonScript_ = script()->ionScript();

    84     if (bailout->frameClass() == FrameSizeClass::None()) {

    85         snapshotOffset_ = bailout->snapshotOffset();

    86         return;

    87     }

    89     // Compute the snapshot offset from the bailout ID.

    90     JitActivation *activation = activations.activation()->asJit();

    91     JSRuntime *rt = activation->compartment()->runtimeFromMainThread();

    92     JitCode *code = rt->jitRuntime()->getBailoutTable(bailout->frameClass());

    93     uintptr_t tableOffset = bailout->tableOffset();

    94     uintptr_t tableStart = reinterpret_cast<uintptr_t>(code->raw());

    96     JS_ASSERT(tableOffset >= tableStart &&

    97               tableOffset < tableStart + code->instructionsSize());

    98     JS_ASSERT((tableOffset - tableStart) % BAILOUT_TABLE_ENTRY_SIZE == 0);

   100     uint32_t bailoutId = ((tableOffset - tableStart) / BAILOUT_TABLE_ENTRY_SIZE) - 1;

   101     JS_ASSERT(bailoutId < BAILOUT_TABLE_SIZE);

   103     snapshotOffset_ = topIonScript_->bailoutToSnapshot(bailoutId);

   104 }

   106 IonBailoutIterator::IonBailoutIterator(const JitActivationIterator &activations,

   107                                        InvalidationBailoutStack *bailout)

   108   : JitFrameIterator(activations),

   109     machine_(bailout->machine())

   110 {

   111     returnAddressToFp_ = bailout->osiPointReturnAddress();

   112     topIonScript_ = bailout->ionScript();

   113     const OsiIndex *osiIndex = topIonScript_->getOsiIndex(returnAddressToFp_);

   115     current_ = (uint8_t*) bailout->fp();

   116     type_ = JitFrame_IonJS;

   117     topFrameSize_ = current_ - bailout->sp();

   118     snapshotOffset_ = osiIndex->snapshotOffset();

   119 }

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