VM: Add dart_precompiled build target, a standalone VM without the JIT compiler.

VM: Add dart_precompiled build target, a standalone VM without the JIT compiler.

This removes most of the compiler-related code from dart_precompiled:
x64 stripped binary size 13M -> 9.1M
ARM stripped binary size 12M -> 8.3M

The precompiled build defines the DART_PRECOMPILED macro. This
stubs out the public interface to the compiler/parser with empty
function bodies.

Use gcc options -ffunction-sections and --gc-sections to make the linker remove
unused functions/symbols.

BUG=
R=rmacnak@google.com

Committed: https://github.com/dart-lang/sdk/commit/f0a35b32607988a669db0d021e43f5211c707828

[Florian Schneider, 2015-11-17 19:11:20]

fschneider@google.com changed reviewers:
+ iposva@google.com, johnmccutchan@google.com, rmacnak@google.com

[Florian Schneider, 2015-11-17 19:11:21]

https://codereview.chromium.org/1459443002/diff/1/runtime/vm/locations.cc
File runtime/vm/locations.cc (left):

https://codereview.chromium.org/1459443002/diff/1/runtime/vm/locations.cc#old...
runtime/vm/locations.cc:10: #include "vm/flow_graph_compiler.h"
Also, removed a couple of random unnecessary #includes which should help build
time.

[rmacnak, 2015-11-17 20:51:19]

Let's also have tests/standalone/precompilation_* use dart_precompiled instead
of dart.

https://codereview.chromium.org/1459443002/diff/1/runtime/bin/bin.gypi
File runtime/bin/bin.gypi (right):

https://codereview.chromium.org/1459443002/diff/1/runtime/bin/bin.gypi#newcod...
runtime/bin/bin.gypi:637: 'generate_snapshot_file#host',
Stub out this not-precompiled snapshot too.

https://codereview.chromium.org/1459443002/diff/1/runtime/bin/bin.gypi#newcod...
runtime/bin/bin.gypi:653: '<(snapshot_cc_file)',
Stub out this not-precompiled snapshot too.

https://codereview.chromium.org/1459443002/diff/1/runtime/vm/compiler.cc
File runtime/vm/compiler.cc (right):

https://codereview.chromium.org/1459443002/diff/1/runtime/vm/compiler.cc#newc...
runtime/vm/compiler.cc:1974: #else
#else // DART_PRECOMPILED

https://codereview.chromium.org/1459443002/diff/1/runtime/vm/compiler.cc#newc...
runtime/vm/compiler.cc:1983: return false;
UNREACHABLE()

https://codereview.chromium.org/1459443002/diff/1/runtime/vm/isolate.cc
File runtime/vm/isolate.cc (right):

https://codereview.chromium.org/1459443002/diff/1/runtime/vm/isolate.cc#newco...
runtime/vm/isolate.cc:1644: }
else {
  ASSERT(Dart::IsRunningPrecompiledCode())
}

https://codereview.chromium.org/1459443002/diff/1/runtime/vm/parser.cc
File runtime/vm/parser.cc (right):

https://codereview.chromium.org/1459443002/diff/1/runtime/vm/parser.cc#newcod...
runtime/vm/parser.cc:14356: #else
// DART_PRECOMPILED

https://codereview.chromium.org/1459443002/diff/1/runtime/vm/precompiler.cc
File runtime/vm/precompiler.cc (right):

https://codereview.chromium.org/1459443002/diff/1/runtime/vm/precompiler.cc#n...
runtime/vm/precompiler.cc:591: cls.EnsureIsFinalized(T);
All the classes should have been finalized before we get here.

https://codereview.chromium.org/1459443002/diff/1/tools/gyp/configurations_ma...
File tools/gyp/configurations_make.gypi (right):

https://codereview.chromium.org/1459443002/diff/1/tools/gyp/configurations_ma...
tools/gyp/configurations_make.gypi:243: '-Wl,--gc-sections',
Do we need to add flags for Mac too?

[Florian Schneider, 2015-11-18 11:44:09]

New stripped binary sizes (with non-precompiled snapshot excluded)

8.0M  out/ReleaseX64/dart_precompiled
7.1M  out/ReleaseXARM/dart_precompiled

https://codereview.chromium.org/1459443002/diff/1/runtime/bin/bin.gypi
File runtime/bin/bin.gypi (right):

https://codereview.chromium.org/1459443002/diff/1/runtime/bin/bin.gypi#newcod...
runtime/bin/bin.gypi:637: 'generate_snapshot_file#host',
On 2015/11/17 20:51:18, rmacnak wrote:
> Stub out this not-precompiled snapshot too.

Done.

https://codereview.chromium.org/1459443002/diff/1/runtime/bin/bin.gypi#newcod...
runtime/bin/bin.gypi:653: '<(snapshot_cc_file)',
On 2015/11/17 20:51:18, rmacnak wrote:
> Stub out this not-precompiled snapshot too.

Done. Replaced with snapshot_empty.cc. This cuts off another ~1M from the
binary.

https://codereview.chromium.org/1459443002/diff/1/runtime/vm/compiler.cc
File runtime/vm/compiler.cc (right):

https://codereview.chromium.org/1459443002/diff/1/runtime/vm/compiler.cc#newc...
runtime/vm/compiler.cc:1974: #else
On 2015/11/17 20:51:18, rmacnak wrote:
> #else // DART_PRECOMPILED

Done.

https://codereview.chromium.org/1459443002/diff/1/runtime/vm/compiler.cc#newc...
runtime/vm/compiler.cc:1983: return false;
On 2015/11/17 20:51:18, rmacnak wrote:
> UNREACHABLE()

Done.

https://codereview.chromium.org/1459443002/diff/1/runtime/vm/isolate.cc
File runtime/vm/isolate.cc (right):

https://codereview.chromium.org/1459443002/diff/1/runtime/vm/isolate.cc#newco...
runtime/vm/isolate.cc:1644: }
On 2015/11/17 20:51:18, rmacnak wrote:
> else {
>   ASSERT(Dart::IsRunningPrecompiledCode())
> }

This may be too strict - e.g. running with --no-background-compilation should be
allowed to leave this field NULL, too.

https://codereview.chromium.org/1459443002/diff/1/runtime/vm/parser.cc
File runtime/vm/parser.cc (right):

https://codereview.chromium.org/1459443002/diff/1/runtime/vm/parser.cc#newcod...
runtime/vm/parser.cc:14356: #else
On 2015/11/17 20:51:18, rmacnak wrote:
> // DART_PRECOMPILED

Done.

https://codereview.chromium.org/1459443002/diff/1/runtime/vm/precompiler.cc
File runtime/vm/precompiler.cc (right):

https://codereview.chromium.org/1459443002/diff/1/runtime/vm/precompiler.cc#n...
runtime/vm/precompiler.cc:591: cls.EnsureIsFinalized(T);
On 2015/11/17 20:51:18, rmacnak wrote:
> All the classes should have been finalized before we get here.

Not true for certain signature classes: If you set a breakpoint in
EnsureFinalized when running a precompiled snapshot you'll see which ones.

There may be something missing in the tree-shaking code though.

https://codereview.chromium.org/1459443002/diff/1/tools/gyp/configurations_ma...
File tools/gyp/configurations_make.gypi (right):

https://codereview.chromium.org/1459443002/diff/1/tools/gyp/configurations_ma...
tools/gyp/configurations_make.gypi:243: '-Wl,--gc-sections',
On 2015/11/17 20:51:18, rmacnak wrote:
> Do we need to add flags for Mac too?

Possibly - I don't have a Mac at hand yet to test it locally, so I'll leave this
for a future CL.

[rmacnak, 2015-11-18 19:00:07]

lgtm

https://codereview.chromium.org/1459443002/diff/1/runtime/vm/isolate.cc
File runtime/vm/isolate.cc (right):

https://codereview.chromium.org/1459443002/diff/1/runtime/vm/isolate.cc#newco...
runtime/vm/isolate.cc:1644: }
On 2015/11/18 11:44:09, Florian Schneider wrote:
> On 2015/11/17 20:51:18, rmacnak wrote:
> > else {
> >   ASSERT(Dart::IsRunningPrecompiledCode())
> > }
> 
> This may be too strict - e.g. running with --no-background-compilation should
be
> allowed to leave this field NULL, too.

Ack.

https://codereview.chromium.org/1459443002/diff/1/runtime/vm/precompiler.cc
File runtime/vm/precompiler.cc (right):

https://codereview.chromium.org/1459443002/diff/1/runtime/vm/precompiler.cc#n...
runtime/vm/precompiler.cc:591: cls.EnsureIsFinalized(T);
On 2015/11/18 11:44:09, Florian Schneider wrote:
> On 2015/11/17 20:51:18, rmacnak wrote:
> > All the classes should have been finalized before we get here.
> 
> Not true for certain signature classes: If you set a breakpoint in
> EnsureFinalized when running a precompiled snapshot you'll see which ones.
> 
> There may be something missing in the tree-shaking code though.

Oh, right. Signature classes may be created as we parse functions.

[Florian Schneider, 2015-11-19 09:13:21]

Committed patchset #3 (id:40001) manually as
f0a35b32607988a669db0d021e43f5211c707828 (presubmit successful).

[Ivan Posva, 2015-11-20 05:14:50]

Alternatively we should consider whether we want to use a value instead of the
mere definition.

-Ivan

https://codereview.chromium.org/1459443002/diff/40001/runtime/vm/compiler.cc
File runtime/vm/compiler.cc (right):

https://codereview.chromium.org/1459443002/diff/40001/runtime/vm/compiler.cc#...
runtime/vm/compiler.cc:80: #ifndef DART_PRECOMPILED
if !defined(DART_PRECOMPILED)