Commit Graph

14 Commits

Author SHA1 Message Date
Ryan Macnak 82bf4bb135 [vm] Fail gracefully when a snapshot is loaded without the proper alignment.
Change-Id: Ie9164d54cbea08d0da5b36bfc36ef1a3e7a46b0b
Reviewed-on: https://dart-review.googlesource.com/53122
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
Commit-Queue: Ryan Macnak <rmacnak@google.com>
2018-04-30 21:12:41 +00:00
Ryan Macnak 0cc70c4a7c [vm] Support for sharing parts of an app snapshot.
In addition, this removes support for seeding the VM isolate snapshot with Instructions and referencing those Instructions in the isolate snapshot. This was leftover from an earlier experiment to share Instructions between a Core-JIT snapshot and App-JIT snapshots. Removing this reclaims the sign bit on Instruction offsets.

Add missing cases to TypeTestingStubFinder::StubNameFromAddresss.

Change-Id: Ie87216b4e284db1dc3eddb12f38ddbe8a841d312
Reviewed-on: https://dart-review.googlesource.com/50620
Commit-Queue: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Alexander Markov <alexmarkov@google.com>
2018-04-27 17:42:16 +00:00
Martin Kustermann 3b414a277c Reland "[VM] Introduction of type testing stubs - Part 1-4"
Relands 165c583d57

    [VM] Introduction of type testing stubs - Part 1

    This CL:

      * Adds a field to [RawAbstractType] which will always hold a pointer
        to the entrypoint of a type testing stub

      * Makes this new field be initialized to a default stub whenever a
        instances are created (e.g. via Type::New(), snapshot reader, ...)

      * Makes the clustered snapshotter write a reference to the
        corresponding [RawInstructions] object when writing the field and do
        the reverse when reading it.

      * Makes us call the type testing stub for performing assert-assignable
        checks.

    To reduce unnecessary loads on callsites, we store the entrypoint of the
    type testing stubs directly in the type objects.  This means that the
    caller of type testing stubs can simply branch there without populating
    a code object first.  This also means that the type testing stubs
    themselves have no access to a pool and we therefore also don't hold on
    to the [Code] object, only the [Instruction] object is necessary.

    The type testing stubs do not setup a frame themselves and also have no
    safepoint.  In the case when the type testing stubs could not determine
    a positive answer they will tail-call a general-purpose stub.

    The general-purpose stub sets up a stub frame, tries to consult a
    [SubtypeTestCache] and bails out to runtime if this was unsuccessful.

    This CL is just the the first, for ease of reviewing.  The actual
    type-specialized type testing stubs will be generated in later CLs.

    Reviewed-on: https://dart-review.googlesource.com/44787

Relands f226c22424

    [VM] Introduction of type testing stubs - Part 2

    This CL starts building type testing stubs specialzed for [Type] objects
    we test against.

    More specifically, it adds support for:

      * Handling obvious fast cases on the call sites (while still having a
        call to stub for negative case)

      * Handling type tests against type parameters, by loading the value
        of the type parameter on the call sites and invoking it's type testing stub.

      * Specialzed type testing stubs for instantiated types where we can
        do [CidRange]-based subtype-checks.

        ==> e.g. String/List<dynamic>

      * Specialzed type testing stubs for instantiated types where we can
        do [CidRange]-based subclass-checks for the class and
        [CidRange]-based subtype-checks for the type arguments.

        ==> e.g. Widget<State>, where we know [Widget] is only extended and not
                 implemented.

      * Specialzed type testing stubs for certain non-instantiated types where we
        can do [CidRange]-based subclass-checks for the class and
        [CidRange]-based subtype-checks for the instantiated type arguments and
        cid based comparisons for type parameters.  (Note that this fast-case migth
        result in some false-negatives!)

        ==> e.g. _HashMapEntry<K, V>, where we know [_HashMapEntry] is only
                 extended and not implemented.

       This optimizes cases where the caller uses `new HashMap<A, B>()` and only
       uses `A` and `B` as key/values (and not subclasses of it).  The false-negative
       can occur when subtypes of A or B are used.  In such cases we fall back to the
       [SubtypeTestCache]-based imlementation.

    Reviewed-on: https://dart-review.googlesource.com/44788

Relands 25f98bcc75

    [VM] Introduction of type testing stubs - Part 3

    The changes include:

      * Make AssertAssignableInstr no longer have a call-summary, which
        helps methods with several parameter checks by not having to
        re-load/re-initialize type arguments registers

      * Lazily create SubtypeTestCaches: We already go to runtime to warm up
        the caches, so we now also create the caches on the first runtime
        call and patch the pool entries.

      * No longer load the destination name into a register: We only need
        the name when we throw an exception, so it is not on the hot path.
        Instead we let the runtime look at the call site, decoding a pool
        index from the instructions stream.  The destination name will be
        available in the pool, at a consecutive index to the subtype cache.

      * Remove the fall-through to N=1 case for probing subtypeing tests,
        since those will always be handled by the optimized stubs.

      * Do not generate optimized stubs for FutureOr<T> (so far it just
        falled-through to TTS).  We can make optimzed version of that later,
        but it requires special subtyping rules.

      * Local code quality improvement in the type-testing-stubs: Avoid
        extra jump at last case of cid-class-range checks.

    There are still a number of optimization opportunities we can do in
    future changes.

    Reviewed-on: https://dart-review.googlesource.com/46984

Relands 2c52480ec8

    [VM] Introduction of type testing stubs - Part 4

    In order to avoid generating type testing stubs for too many types in
    the system - and thereby potentially cause an increase in code size -
    this change introduces a smarter way to decide for which types we should
    generate optimized type testing stubs.

    The precompiler creates a [TypeUsageInfo] which we use to collect
    information.  More specifically:

       a) We collect the destination types for all type checks we emit
          (we do this inside AssertAssignableInstr::EmitNativeCode).

          -> These are types we might want to generate optimized type testing
             stubs for.

       b) We collect type argument vectors used in instance creations (we do
          this inside AllocateObjectInstr::EmitNativeCode) and keep a set of
          of used type argument vectors for each class.

    After the precompiler has finished compiling normal code we scan the set
    of destination types collected in a) for uninstantiated types (or more
    specifically, type parameter types).

    We then propagate the type argument vectors used on object allocation sites,
    which were collected in b), in order to find out what kind of types are flowing
    into those type parameters.

    This allows us to extend the set of types which we test against, by
    adding the types that flow into type parameters.

    We use this final augmented set of destination types as a "filter" when
    making the decision whether to generate an optimized type testing stub
    for a given type.

    Reviewed-on: https://dart-review.googlesource.com/48640

Issue https://github.com/dart-lang/sdk/issues/32603

Closes https://github.com/dart-lang/sdk/issues/32852

Change-Id: Ib79fbe7f043aa88f32bddad62d7656c638914b44
Reviewed-on: https://dart-review.googlesource.com/50944
Commit-Queue: Martin Kustermann <kustermann@google.com>
Reviewed-by: Régis Crelier <regis@google.com>
2018-04-13 09:06:56 +00:00
Ryan Macnak 6db4ea4ca5 [vm] Use unsigned varints when possible in the clustered snapshot.
- References
 - ROData offsets
 - Cluster sizes
 - Variable-length object lengths

flutter_gallery:
Isolate(CodeSize): 2384368 -> 2302404 (-3.4%)
Total(CodeSize): 11651807 -> 11569439 (-0.7%)

Change-Id: I59ea4d4a48fcbecf5236d3895b495c88ed548ec3
Reviewed-on: https://dart-review.googlesource.com/50841
Reviewed-by: Ben Konyi <bkonyi@google.com>
Commit-Queue: Ryan Macnak <rmacnak@google.com>
2018-04-12 17:37:39 +00:00
Ryan Macnak b3c94b5d52 Revert "Reland "[VM] Introduction of type testing stubs - Part 1-4""
This reverts commit 34763bc4c9.

Bug: https://github.com/dart-lang/sdk/issues/32852
Change-Id: I2131907d7036644707d5109a951969fc48dd74e1
Reviewed-on: https://dart-review.googlesource.com/50842
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Commit-Queue: Ryan Macnak <rmacnak@google.com>
2018-04-11 22:42:59 +00:00
Vyacheslav Egorov 0b83be906c [vm/compiler/aot] Introduce ways to dump instruction size statistics.
We add two things:

* --print_instruction_stats makes compiler dump per IL instruction size
breakdown (how many bytes of code were produced from specific instruction
kinds). This was largely implemented by kustermann@ in
https://codereview.chromium.org/2584613002/ and this CL does only few changes
to the original implementation, namely more uniform handling of slow-path code
and puts statistics object into RawInstructions (which has free space due to
alignment) instead of RawCode.

* --print_instructions_sizes_to=symbols.json makes compiler dump per Instruction
object size breakdown into a JSON file. This JSON file can later be processed
with pkg/vm/tool/run_binary_size_analysis.dart script to produce interactive
binary size diagram similar to runtime/third_party/binary_size tool.

Change-Id: Ied4965b9a0a91b3025eefbe981ecd47cdcf782d6
Reviewed-on: https://dart-review.googlesource.com/50501
Commit-Queue: Vyacheslav Egorov <vegorov@google.com>
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
2018-04-11 13:03:16 +00:00
Martin Kustermann 34763bc4c9 Reland "[VM] Introduction of type testing stubs - Part 1-4"
Relands 165c583d57

    [VM] Introduction of type testing stubs - Part 1

    This CL:

      * Adds a field to [RawAbstractType] which will always hold a pointer
        to the entrypoint of a type testing stub

      * Makes this new field be initialized to a default stub whenever a
        instances are created (e.g. via Type::New(), snapshot reader, ...)

      * Makes the clustered snapshotter write a reference to the
        corresponding [RawInstructions] object when writing the field and do
        the reverse when reading it.

      * Makes us call the type testing stub for performing assert-assignable
        checks.

    To reduce unnecessary loads on callsites, we store the entrypoint of the
    type testing stubs directly in the type objects.  This means that the
    caller of type testing stubs can simply branch there without populating
    a code object first.  This also means that the type testing stubs
    themselves have no access to a pool and we therefore also don't hold on
    to the [Code] object, only the [Instruction] object is necessary.

    The type testing stubs do not setup a frame themselves and also have no
    safepoint.  In the case when the type testing stubs could not determine
    a positive answer they will tail-call a general-purpose stub.

    The general-purpose stub sets up a stub frame, tries to consult a
    [SubtypeTestCache] and bails out to runtime if this was unsuccessful.

    This CL is just the the first, for ease of reviewing.  The actual
    type-specialized type testing stubs will be generated in later CLs.

    Reviewed-on: https://dart-review.googlesource.com/44787

Relands f226c22424

    [VM] Introduction of type testing stubs - Part 2

    This CL starts building type testing stubs specialzed for [Type] objects
    we test against.

    More specifically, it adds support for:

      * Handling obvious fast cases on the call sites (while still having a
        call to stub for negative case)

      * Handling type tests against type parameters, by loading the value
        of the type parameter on the call sites and invoking it's type testing stub.

      * Specialzed type testing stubs for instantiated types where we can
        do [CidRange]-based subtype-checks.

        ==> e.g. String/List<dynamic>

      * Specialzed type testing stubs for instantiated types where we can
        do [CidRange]-based subclass-checks for the class and
        [CidRange]-based subtype-checks for the type arguments.

        ==> e.g. Widget<State>, where we know [Widget] is only extended and not
                 implemented.

      * Specialzed type testing stubs for certain non-instantiated types where we
        can do [CidRange]-based subclass-checks for the class and
        [CidRange]-based subtype-checks for the instantiated type arguments and
        cid based comparisons for type parameters.  (Note that this fast-case migth
        result in some false-negatives!)

        ==> e.g. _HashMapEntry<K, V>, where we know [_HashMapEntry] is only
                 extended and not implemented.

       This optimizes cases where the caller uses `new HashMap<A, B>()` and only
       uses `A` and `B` as key/values (and not subclasses of it).  The false-negative
       can occur when subtypes of A or B are used.  In such cases we fall back to the
       [SubtypeTestCache]-based imlementation.

    Reviewed-on: https://dart-review.googlesource.com/44788

Relands 25f98bcc75

    [VM] Introduction of type testing stubs - Part 3

    The changes include:

      * Make AssertAssignableInstr no longer have a call-summary, which
        helps methods with several parameter checks by not having to
        re-load/re-initialize type arguments registers

      * Lazily create SubtypeTestCaches: We already go to runtime to warm up
        the caches, so we now also create the caches on the first runtime
        call and patch the pool entries.

      * No longer load the destination name into a register: We only need
        the name when we throw an exception, so it is not on the hot path.
        Instead we let the runtime look at the call site, decoding a pool
        index from the instructions stream.  The destination name will be
        available in the pool, at a consecutive index to the subtype cache.

      * Remove the fall-through to N=1 case for probing subtypeing tests,
        since those will always be handled by the optimized stubs.

      * Do not generate optimized stubs for FutureOr<T> (so far it just
        falled-through to TTS).  We can make optimzed version of that later,
        but it requires special subtyping rules.

      * Local code quality improvement in the type-testing-stubs: Avoid
        extra jump at last case of cid-class-range checks.

    There are still a number of optimization opportunities we can do in
    future changes.

    Reviewed-on: https://dart-review.googlesource.com/46984

Relands 2c52480ec8

    [VM] Introduction of type testing stubs - Part 4

    In order to avoid generating type testing stubs for too many types in
    the system - and thereby potentially cause an increase in code size -
    this change introduces a smarter way to decide for which types we should
    generate optimized type testing stubs.

    The precompiler creates a [TypeUsageInfo] which we use to collect
    information.  More specifically:

       a) We collect the destination types for all type checks we emit
          (we do this inside AssertAssignableInstr::EmitNativeCode).

          -> These are types we might want to generate optimized type testing
             stubs for.

       b) We collect type argument vectors used in instance creations (we do
          this inside AllocateObjectInstr::EmitNativeCode) and keep a set of
          of used type argument vectors for each class.

    After the precompiler has finished compiling normal code we scan the set
    of destination types collected in a) for uninstantiated types (or more
    specifically, type parameter types).

    We then propagate the type argument vectors used on object allocation sites,
    which were collected in b), in order to find out what kind of types are flowing
    into those type parameters.

    This allows us to extend the set of types which we test against, by
    adding the types that flow into type parameters.

    We use this final augmented set of destination types as a "filter" when
    making the decision whether to generate an optimized type testing stub
    for a given type.

    Reviewed-on: https://dart-review.googlesource.com/48640

Issue https://github.com/dart-lang/sdk/issues/32603

Change-Id: I6d33d4ca3d5187a1eb1664078c003061855f0160
Reviewed-on: https://dart-review.googlesource.com/50482
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
Commit-Queue: Martin Kustermann <kustermann@google.com>
2018-04-10 12:20:10 +00:00
Martin Kustermann 1e997ee6b7 Revert "Reland "[VM] Introduction of type testing stubs - Part 1-4""
This reverts commit 8054409a02.

Reason for revert: Potential cause of flakes, not entirely clear yet if it was caused by this CL.

Change-Id: Icb119a107f22245ba2f303c7f2ae11f061f605f5
Reviewed-on: https://dart-review.googlesource.com/50261
Reviewed-by: Martin Kustermann <kustermann@google.com>
Commit-Queue: Martin Kustermann <kustermann@google.com>
2018-04-09 14:29:07 +00:00
Martin Kustermann 8054409a02 Reland "[VM] Introduction of type testing stubs - Part 1-4"
Relands 165c583d57

    [VM] Introduction of type testing stubs - Part 1

    This CL:

      * Adds a field to [RawAbstractType] which will always hold a pointer
        to the entrypoint of a type testing stub

      * Makes this new field be initialized to a default stub whenever a
        instances are created (e.g. via Type::New(), snapshot reader, ...)

      * Makes the clustered snapshotter write a reference to the
        corresponding [RawInstructions] object when writing the field and do
        the reverse when reading it.

      * Makes us call the type testing stub for performing assert-assignable
        checks.

    To reduce unnecessary loads on callsites, we store the entrypoint of the
    type testing stubs directly in the type objects.  This means that the
    caller of type testing stubs can simply branch there without populating
    a code object first.  This also means that the type testing stubs
    themselves have no access to a pool and we therefore also don't hold on
    to the [Code] object, only the [Instruction] object is necessary.

    The type testing stubs do not setup a frame themselves and also have no
    safepoint.  In the case when the type testing stubs could not determine
    a positive answer they will tail-call a general-purpose stub.

    The general-purpose stub sets up a stub frame, tries to consult a
    [SubtypeTestCache] and bails out to runtime if this was unsuccessful.

    This CL is just the the first, for ease of reviewing.  The actual
    type-specialized type testing stubs will be generated in later CLs.

    Reviewed-on: https://dart-review.googlesource.com/44787

Relands f226c22424

    [VM] Introduction of type testing stubs - Part 2

    This CL starts building type testing stubs specialzed for [Type] objects
    we test against.

    More specifically, it adds support for:

      * Handling obvious fast cases on the call sites (while still having a
        call to stub for negative case)

      * Handling type tests against type parameters, by loading the value
        of the type parameter on the call sites and invoking it's type testing stub.

      * Specialzed type testing stubs for instantiated types where we can
        do [CidRange]-based subtype-checks.

        ==> e.g. String/List<dynamic>

      * Specialzed type testing stubs for instantiated types where we can
        do [CidRange]-based subclass-checks for the class and
        [CidRange]-based subtype-checks for the type arguments.

        ==> e.g. Widget<State>, where we know [Widget] is only extended and not
                 implemented.

      * Specialzed type testing stubs for certain non-instantiated types where we
        can do [CidRange]-based subclass-checks for the class and
        [CidRange]-based subtype-checks for the instantiated type arguments and
        cid based comparisons for type parameters.  (Note that this fast-case migth
        result in some false-negatives!)

        ==> e.g. _HashMapEntry<K, V>, where we know [_HashMapEntry] is only
                 extended and not implemented.

       This optimizes cases where the caller uses `new HashMap<A, B>()` and only
       uses `A` and `B` as key/values (and not subclasses of it).  The false-negative
       can occur when subtypes of A or B are used.  In such cases we fall back to the
       [SubtypeTestCache]-based imlementation.

    Reviewed-on: https://dart-review.googlesource.com/44788

Relands 25f98bcc75

    [VM] Introduction of type testing stubs - Part 3

    The changes include:

      * Make AssertAssignableInstr no longer have a call-summary, which
        helps methods with several parameter checks by not having to
        re-load/re-initialize type arguments registers

      * Lazily create SubtypeTestCaches: We already go to runtime to warm up
        the caches, so we now also create the caches on the first runtime
        call and patch the pool entries.

      * No longer load the destination name into a register: We only need
        the name when we throw an exception, so it is not on the hot path.
        Instead we let the runtime look at the call site, decoding a pool
        index from the instructions stream.  The destination name will be
        available in the pool, at a consecutive index to the subtype cache.

      * Remove the fall-through to N=1 case for probing subtypeing tests,
        since those will always be handled by the optimized stubs.

      * Do not generate optimized stubs for FutureOr<T> (so far it just
        falled-through to TTS).  We can make optimzed version of that later,
        but it requires special subtyping rules.

      * Local code quality improvement in the type-testing-stubs: Avoid
        extra jump at last case of cid-class-range checks.

    There are still a number of optimization opportunities we can do in
    future changes.

    Reviewed-on: https://dart-review.googlesource.com/46984

Relands 2c52480ec8

    [VM] Introduction of type testing stubs - Part 4

    In order to avoid generating type testing stubs for too many types in
    the system - and thereby potentially cause an increase in code size -
    this change introduces a smarter way to decide for which types we should
    generate optimized type testing stubs.

    The precompiler creates a [TypeUsageInfo] which we use to collect
    information.  More specifically:

       a) We collect the destination types for all type checks we emit
          (we do this inside AssertAssignableInstr::EmitNativeCode).

          -> These are types we might want to generate optimized type testing
             stubs for.

       b) We collect type argument vectors used in instance creations (we do
          this inside AllocateObjectInstr::EmitNativeCode) and keep a set of
          of used type argument vectors for each class.

    After the precompiler has finished compiling normal code we scan the set
    of destination types collected in a) for uninstantiated types (or more
    specifically, type parameter types).

    We then propagate the type argument vectors used on object allocation sites,
    which were collected in b), in order to find out what kind of types are flowing
    into those type parameters.

    This allows us to extend the set of types which we test against, by
    adding the types that flow into type parameters.

    We use this final augmented set of destination types as a "filter" when
    making the decision whether to generate an optimized type testing stub
    for a given type.

    Reviewed-on: https://dart-review.googlesource.com/48640

Issue https://github.com/dart-lang/sdk/issues/32603

Change-Id: I44a1d5d4b27454ae026aef2a301aada3dd399ea0
Reviewed-on: https://dart-review.googlesource.com/49861
Commit-Queue: Martin Kustermann <kustermann@google.com>
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
2018-04-09 11:25:36 +00:00
Martin Kustermann dbb1d3d44f Revert "[VM] Introduction of type testing stubs - Part 1-4"
This reverts commit 2c52480ec8.
This reverts commit 25f98bcc75.
This reverts commit f226c22424.
This reverts commit 165c583d57.

Change-Id: I3892d672b9ca0b0acc0b9b83c32ecc92355839c2
Reviewed-on: https://dart-review.googlesource.com/49843
Reviewed-by: Martin Kustermann <kustermann@google.com>
2018-04-06 08:35:01 +00:00
Martin Kustermann 165c583d57 [VM] Introduction of type testing stubs - Part 1
This CL:

  * Adds a field to [RawAbstractType] which will always hold a pointer
    to the entrypoint of a type testing stub

  * Makes this new field be initialized to a default stub whenever a
    instances are created (e.g. via Type::New(), snapshot reader, ...)

  * Makes the clustered snapshotter write a reference to the
    corresponding [RawInstructions] object when writing the field and do
    the reverse when reading it.

  * Makes us call the type testing stub for performing assert-assignable
    checks.

To reduce unnecessary loads on callsites, we store the entrypoint of the
type testing stubs directly in the type objects.  This means that the
caller of type testing stubs can simply branch there without populating
a code object first.  This also means that the type testing stubs
themselves have no access to a pool and we therefore also don't hold on
to the [Code] object, only the [Instruction] object is necessary.

The type testing stubs do not setup a frame themselves and also have no
safepoint.  In the case when the type testing stubs could not determine
a positive answer they will tail-call a general-purpose stub.

The general-purpose stub sets up a stub frame, tries to consult a
[SubtypeTestCache] and bails out to runtime if this was unsuccessful.

This CL is just the the first, for ease of reviewing.  The actual
type-specialized type testing stubs will be generated in later CLs.

Issue https://github.com/dart-lang/sdk/issues/31798

Change-Id: I174a11b3b812799f399a60af799144c2ba3c26ec
Reviewed-on: https://dart-review.googlesource.com/44787
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
Reviewed-by: Régis Crelier <regis@google.com>
2018-04-06 07:00:50 +00:00
Ryan Macnak 22ccad1aa6 [vm] Stream writing snapshots as assembly to reduce peak memory usage.
Bug: US-449
Change-Id: Ic1ce6881b54c8c0eb7c93cbbda8057d7268bb3fd
Reviewed-on: https://dart-review.googlesource.com/45580
Commit-Queue: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Alexander Markov <alexmarkov@google.com>
2018-03-08 19:26:17 +00:00
Ryan Macnak cbb7cb360b [vm] Include the content of image pages into --print-snapshot-sizes-verbose.
E.g.,
             Cluster   Objs     Size Fraction Cumulative
    (RO)Instructions      0 11465312 0.500079 0.500079
        (RO)StackMap  97579  3525312 0.153763 0.653842
   (RO)CodeSourceMap  22358  1752087 0.076420 0.730262
   (RO)OneByteString  30427  1644273 0.071718 0.801980
          ObjectPool  27233  1077927 0.047016 0.848995
               Array  25995  1029434 0.044901 0.893896
            Function  36468   924984 0.040345 0.934241
                Code  35686   782093 0.034112 0.968353
               Class   4026   177417 0.007738 0.976091
           TypedData  33768   125511 0.005474 0.981566
                 ...

Change-Id: I9f1e45ce85df6a4509f6d9fb2c28b41157872941
Reviewed-on: https://dart-review.googlesource.com/20262
Reviewed-by: Siva Chandra <sivachandra@google.com>
Commit-Queue: Ryan Macnak <rmacnak@google.com>
2017-11-11 00:19:18 +00:00
Ryan Macnak 8ed836fd6d [vm] Factor out the image snapshot code.
Prep for aligning image pages.

Bug: https://github.com/dart-lang/sdk/issues/30978
Change-Id: I5abd5d73ac9fed427942218a827e144fc74593de
Reviewed-on: https://dart-review.googlesource.com/18121
Reviewed-by: Siva Annamalai <asiva@google.com>
2017-11-02 00:57:42 +00:00