Last snapshot bits to get working precompiled hello_world on x64.

-Setup heap page for precompiled instructions to make heap verifier etc happy.
-Pre-mark instructions when writing the snapshot.
-Write the megamorphic miss function to the snapshot.
-Add missing ExceptionHandlers for megamorphic miss code.
-Add missing C++ entry points.
-Relocate Function and Code entry_points_ when reading precompiled snapshot.
-Don't try to load a script again when running from a precompiled snapshot.

R=asiva@google.com

Committed: https://github.com/dart-lang/sdk/commit/9764a9f03707b5d47fb961a5d1887bbd6256158a

[rmacnak, 2015-09-11 00:46:48]

rmacnak@google.com changed reviewers:
+ asiva@google.com, iposva@google.com

[rmacnak, 2015-09-11 00:46:48]

Together with my and Florian's outstanding CLs, hello_world runs precompiled!

[siva, 2015-09-14 21:29:34]

https://codereview.chromium.org/1336763002/diff/40001/runtime/vm/dart.cc
File runtime/vm/dart.cc (right):

https://codereview.chromium.org/1336763002/diff/40001/runtime/vm/dart.cc#newc...
runtime/vm/dart.cc:320: if (Object::instructions_snapshot_buffer() == NULL) {
maybe we should have a readable accessor, something like

Dart::IsRunningPrecompiledCode()

https://codereview.chromium.org/1336763002/diff/40001/runtime/vm/isolate.cc
File runtime/vm/isolate.cc (right):

https://codereview.chromium.org/1336763002/diff/40001/runtime/vm/isolate.cc#n...
runtime/vm/isolate.cc:888: *reinterpret_cast<const
uint64_t*>(instructions_snapshot));
Would be better to do

Snapshot* instr_snapshot = Snapshot::SetupFromBuffer(instructions_snapshot);

intptr_t snapshot_size = instr_snapshot->length();

void* instructions_start = reinterpret_cast<void*>(instr_snapshot->content());

https://codereview.chromium.org/1336763002/diff/40001/runtime/vm/megamorphic_...
File runtime/vm/megamorphic_cache_table.cc (right):

https://codereview.chromium.org/1336763002/diff/40001/runtime/vm/megamorphic_...
runtime/vm/megamorphic_cache_table.cc:143: }
This code is another CL and as discussed offline might go away.

https://codereview.chromium.org/1336763002/diff/40001/runtime/vm/megamorphic_...
File runtime/vm/megamorphic_cache_table.h (right):

https://codereview.chromium.org/1336763002/diff/40001/runtime/vm/megamorphic_...
runtime/vm/megamorphic_cache_table.h:39: void WriteTo(SnapshotWriter* writer);
This change seems to be in the other CL too.

https://codereview.chromium.org/1336763002/diff/40001/runtime/vm/object.cc
File runtime/vm/object.cc (right):

https://codereview.chromium.org/1336763002/diff/40001/runtime/vm/object.cc#ne...
runtime/vm/object.cc:843: }
Shouldn't this be:

if (obj->IsMarked()) {
  // Precompiled instructions are loaded pre_marked.
  ASSERT(Dart::IsRunningPrecompiledCode());
  ASSERT(obj.IsInstructions());
} else {
  obj->SetMarkBitUnsyncronized();

}

https://codereview.chromium.org/1336763002/diff/40001/runtime/vm/pages.cc
File runtime/vm/pages.cc (right):

https://codereview.chromium.org/1336763002/diff/40001/runtime/vm/pages.cc#new...
runtime/vm/pages.cc:1059: #endif
Please move this print statement above the MutexLocker stuff

https://codereview.chromium.org/1336763002/diff/40001/runtime/vm/raw_object_s...
File runtime/vm/raw_object_snapshot.cc (right):

https://codereview.chromium.org/1336763002/diff/40001/runtime/vm/raw_object_s...
runtime/vm/raw_object_snapshot.cc:1254: }
can we have a local variable tags and do all this bit setting magic in the local
variable and write that tags out instead of changing the bits and restoring
them.

https://codereview.chromium.org/1336763002/diff/40001/runtime/vm/snapshot.cc
File runtime/vm/snapshot.cc (right):

https://codereview.chromium.org/1336763002/diff/40001/runtime/vm/snapshot.cc#...
runtime/vm/snapshot.cc:1235: }
This style of setting and unsetting the mark bit and VM heap object bit makes me
a bit nervous, can we instead pull the first quad word being written out outside
the loop and do the bit setting on that quad word.

[rmacnak, 2015-09-15 20:07:45]

https://codereview.chromium.org/1336763002/diff/40001/runtime/vm/dart.cc
File runtime/vm/dart.cc (right):

https://codereview.chromium.org/1336763002/diff/40001/runtime/vm/dart.cc#newc...
runtime/vm/dart.cc:320: if (Object::instructions_snapshot_buffer() == NULL) {
On 2015/09/14 21:29:33, siva wrote:
> maybe we should have a readable accessor, something like
> 
> Dart::IsRunningPrecompiledCode()

Done.

https://codereview.chromium.org/1336763002/diff/40001/runtime/vm/megamorphic_...
File runtime/vm/megamorphic_cache_table.cc (right):

https://codereview.chromium.org/1336763002/diff/40001/runtime/vm/megamorphic_...
runtime/vm/megamorphic_cache_table.cc:143: }
On 2015/09/14 21:29:34, siva wrote:
> This code is another CL and as discussed offline might go away.

Dropped.

https://codereview.chromium.org/1336763002/diff/40001/runtime/vm/megamorphic_...
File runtime/vm/megamorphic_cache_table.h (right):

https://codereview.chromium.org/1336763002/diff/40001/runtime/vm/megamorphic_...
runtime/vm/megamorphic_cache_table.h:39: void WriteTo(SnapshotWriter* writer);
On 2015/09/14 21:29:34, siva wrote:
> This change seems to be in the other CL too.

Dropped.

https://codereview.chromium.org/1336763002/diff/40001/runtime/vm/object.cc
File runtime/vm/object.cc (right):

https://codereview.chromium.org/1336763002/diff/40001/runtime/vm/object.cc#ne...
runtime/vm/object.cc:843: }
On 2015/09/14 21:29:34, siva wrote:
> Shouldn't this be:
> 
> if (obj->IsMarked()) {
>   // Precompiled instructions are loaded pre_marked.
>   ASSERT(Dart::IsRunningPrecompiledCode());
>   ASSERT(obj.IsInstructions());
> } else {
>   obj->SetMarkBitUnsyncronized();
> 
> }

Done.

https://codereview.chromium.org/1336763002/diff/40001/runtime/vm/pages.cc
File runtime/vm/pages.cc (right):

https://codereview.chromium.org/1336763002/diff/40001/runtime/vm/pages.cc#new...
runtime/vm/pages.cc:1059: #endif
On 2015/09/14 21:29:34, siva wrote:
> Please move this print statement above the MutexLocker stuff

Done.

https://codereview.chromium.org/1336763002/diff/40001/runtime/vm/raw_object_s...
File runtime/vm/raw_object_snapshot.cc (right):

https://codereview.chromium.org/1336763002/diff/40001/runtime/vm/raw_object_s...
runtime/vm/raw_object_snapshot.cc:1254: }
On 2015/09/14 21:29:34, siva wrote:
> can we have a local variable tags and do all this bit setting magic in the
local
> variable and write that tags out instead of changing the bits and restoring
> them.

Done.

https://codereview.chromium.org/1336763002/diff/40001/runtime/vm/snapshot.cc
File runtime/vm/snapshot.cc (right):

https://codereview.chromium.org/1336763002/diff/40001/runtime/vm/snapshot.cc#...
runtime/vm/snapshot.cc:1235: }
On 2015/09/14 21:29:34, siva wrote:
> This style of setting and unsetting the mark bit and VM heap object bit makes
me
> a bit nervous, can we instead pull the first quad word being written out
outside
> the loop and do the bit setting on that quad word.

Done.

[siva, 2015-09-15 23:22:01]

https://codereview.chromium.org/1336763002/diff/60001/runtime/vm/isolate.cc
File runtime/vm/isolate.cc (right):

https://codereview.chromium.org/1336763002/diff/60001/runtime/vm/isolate.cc#n...
runtime/vm/isolate.cc:891: reinterpret_cast<uword>(instructions_snapshot) +
header_size);
As discussed offline it might be more readable to define a class
InsrtuctionSnapshot and have accessors length() and context() similar to the
regular Snapshot class.

You could move the header_size stuff also into that class.

https://codereview.chromium.org/1336763002/diff/60001/runtime/vm/object.cc
File runtime/vm/object.cc (right):

https://codereview.chromium.org/1336763002/diff/60001/runtime/vm/object.cc#ne...
runtime/vm/object.cc:840: ASSERT(Object::IsRunningPrecompiledCode());
Yes, here it would be ASSERT(Dart::IsRunningPrecompiledCode()) which makes it
more readable.

https://codereview.chromium.org/1336763002/diff/60001/runtime/vm/object.h
File runtime/vm/object.h (right):

https://codereview.chromium.org/1336763002/diff/60001/runtime/vm/object.h#new...
runtime/vm/object.h:498: return instructions_snapshot_buffer != NULL;
instructions_snapshot_buffer_

https://codereview.chromium.org/1336763002/diff/60001/runtime/vm/object.h#new...
runtime/vm/object.h:499: }
We should move instructions_snapshot_buffer_ field to 'class Dart' so that the
code is more readable when using
Dart::IsRunningPrecompiledCode() instead of Object::IsRunningPrecompiledCode().

https://codereview.chromium.org/1336763002/diff/60001/runtime/vm/pages.cc
File runtime/vm/pages.cc (right):

https://codereview.chromium.org/1336763002/diff/60001/runtime/vm/pages.cc#new...
runtime/vm/pages.cc:217: ASSERT(Object::instructions_snapshot_buffer() == NULL);
ASSERT(!Dart::IsRunningPrecompiledCode());

https://codereview.chromium.org/1336763002/diff/60001/runtime/vm/raw_object.h
File runtime/vm/raw_object.h (right):

https://codereview.chromium.org/1336763002/diff/60001/runtime/vm/raw_object.h...
runtime/vm/raw_object.h:381: }
This is not used anymore I guess, it can be removed.

https://codereview.chromium.org/1336763002/diff/60001/runtime/vm/raw_object_s...
File runtime/vm/raw_object_snapshot.cc (right):

https://codereview.chromium.org/1336763002/diff/60001/runtime/vm/raw_object_s...
runtime/vm/raw_object_snapshot.cc:1241: // TODO(asiva): Don't mutate object
headers during serialization.
Is this temporary restore of tags stuff necessary now that you are extracting
the tags and writing it out and if you fix GetOffsetFor to use SizeFromClass
(see comment in snapshot.cc file).

https://codereview.chromium.org/1336763002/diff/60001/runtime/vm/snapshot.cc
File runtime/vm/snapshot.cc (right):

https://codereview.chromium.org/1336763002/diff/60001/runtime/vm/snapshot.cc#...
runtime/vm/snapshot.cc:1146: next_offset_ += instructions->Size();
if you used instructions->SizeFromClass() you would avoid having to save and
restore the tags stuff that you are currently doing around the call to
GetInstructionsId()

[rmacnak, 2015-09-16 01:34:45]

https://chromiumcodereview.appspot.com/1336763002/diff/60001/runtime/vm/objec...
File runtime/vm/object.cc (right):

https://chromiumcodereview.appspot.com/1336763002/diff/60001/runtime/vm/objec...
runtime/vm/object.cc:840: ASSERT(Object::IsRunningPrecompiledCode());
On 2015/09/15 23:22:01, siva wrote:
> Yes, here it would be ASSERT(Dart::IsRunningPrecompiledCode()) which makes it
> more readable.

Done.

https://chromiumcodereview.appspot.com/1336763002/diff/60001/runtime/vm/object.h
File runtime/vm/object.h (right):

https://chromiumcodereview.appspot.com/1336763002/diff/60001/runtime/vm/objec...
runtime/vm/object.h:498: return instructions_snapshot_buffer != NULL;
On 2015/09/15 23:22:01, siva wrote:
> instructions_snapshot_buffer_

Done.

https://chromiumcodereview.appspot.com/1336763002/diff/60001/runtime/vm/pages.cc
File runtime/vm/pages.cc (right):

https://chromiumcodereview.appspot.com/1336763002/diff/60001/runtime/vm/pages...
runtime/vm/pages.cc:217: ASSERT(Object::instructions_snapshot_buffer() == NULL);
On 2015/09/15 23:22:01, siva wrote:
> ASSERT(!Dart::IsRunningPrecompiledCode());

Done.

https://chromiumcodereview.appspot.com/1336763002/diff/60001/runtime/vm/raw_o...
File runtime/vm/raw_object.h (right):

https://chromiumcodereview.appspot.com/1336763002/diff/60001/runtime/vm/raw_o...
runtime/vm/raw_object.h:381: }
On 2015/09/15 23:22:01, siva wrote:
> This is not used anymore I guess, it can be removed.

Done.

https://chromiumcodereview.appspot.com/1336763002/diff/60001/runtime/vm/raw_o...
File runtime/vm/raw_object_snapshot.cc (right):

https://chromiumcodereview.appspot.com/1336763002/diff/60001/runtime/vm/raw_o...
runtime/vm/raw_object_snapshot.cc:1241: // TODO(asiva): Don't mutate object
headers during serialization.
On 2015/09/15 23:22:01, siva wrote:
> Is this temporary restore of tags stuff necessary now that you are extracting
> the tags and writing it out and if you fix GetOffsetFor to use SizeFromClass
> (see comment in snapshot.cc file).

Dropped.

https://chromiumcodereview.appspot.com/1336763002/diff/60001/runtime/vm/snaps...
File runtime/vm/snapshot.cc (right):

https://chromiumcodereview.appspot.com/1336763002/diff/60001/runtime/vm/snaps...
runtime/vm/snapshot.cc:1146: next_offset_ += instructions->Size();
On 2015/09/15 23:22:01, siva wrote:
> if you used instructions->SizeFromClass() you would avoid having to save and
> restore the tags stuff that you are currently doing around the call to
> GetInstructionsId()

Using Instructions::InstanceSize instead.

[siva, 2015-09-16 16:45:41]

lgtm

https://codereview.chromium.org/1336763002/diff/100001/runtime/vm/dart.cc
File runtime/vm/dart.cc (right):

https://codereview.chromium.org/1336763002/diff/100001/runtime/vm/dart.cc#new...
runtime/vm/dart.cc:349: // When running precompiled, the megamorphic miss
function/code come from the
function/code comes from

https://codereview.chromium.org/1336763002/diff/100001/runtime/vm/isolate.cc
File runtime/vm/isolate.cc (right):

https://codereview.chromium.org/1336763002/diff/100001/runtime/vm/isolate.cc#...
runtime/vm/isolate.cc:896: OS::Print("Precompiled instructions are at [%" Px ",
%" Px ")\n",
0x%" ..... 0x%" ....

https://codereview.chromium.org/1336763002/diff/100001/runtime/vm/pages.cc
File runtime/vm/pages.cc (right):

https://codereview.chromium.org/1336763002/diff/100001/runtime/vm/pages.cc#ne...
runtime/vm/pages.cc:1049: OS::Print("Precompiled instructions page at [%" Px ",
%" Px ")\n",
0x%" Px...... 0x%"....

[rmacnak, 2015-09-16 18:17:18]

https://codereview.chromium.org/1336763002/diff/100001/runtime/vm/dart.cc
File runtime/vm/dart.cc (right):

https://codereview.chromium.org/1336763002/diff/100001/runtime/vm/dart.cc#new...
runtime/vm/dart.cc:349: // When running precompiled, the megamorphic miss
function/code come from the
On 2015/09/16 16:45:41, siva wrote:
> function/code comes from

Done.

https://codereview.chromium.org/1336763002/diff/100001/runtime/vm/isolate.cc
File runtime/vm/isolate.cc (right):

https://codereview.chromium.org/1336763002/diff/100001/runtime/vm/isolate.cc#...
runtime/vm/isolate.cc:896: OS::Print("Precompiled instructions are at [%" Px ",
%" Px ")\n",
On 2015/09/16 16:45:41, siva wrote:
> 0x%" ..... 0x%" ....

Done.

https://codereview.chromium.org/1336763002/diff/100001/runtime/vm/pages.cc
File runtime/vm/pages.cc (right):

https://codereview.chromium.org/1336763002/diff/100001/runtime/vm/pages.cc#ne...
runtime/vm/pages.cc:1049: OS::Print("Precompiled instructions page at [%" Px ",
%" Px ")\n",
On 2015/09/16 16:45:41, siva wrote:
> 0x%" Px...... 0x%"....

Done.

[rmacnak, 2015-09-16 18:23:02]

Committed patchset #9 (id:160001) manually as
9764a9f03707b5d47fb961a5d1887bbd6256158a (presubmit successful).