This CL introduces an import section that names functions to be imported
as well as a CallImport bytecode to call imports from this table.

R=binji@chromium.org,bradnelson@chromium.org
LOG=Y
BUG=chromium:575167

Review URL: https://codereview.chromium.org/1709653002

Cr-Commit-Position: refs/heads/master@{#34157}

R=ahaas@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1698133002

Cr-Commit-Position: refs/heads/master@{#33999}

Add a section identifier for declaring a start function as an index into
the function table. (This could also be done as a decl flag on the
function, but don't feel strongly here, since we probably want to redo
this when adding an import/export section.)

The start function must accept no parameters. Its return value is
currently ignored.

R=binji@chromium.org,bradnelson@chromium.org
BUG=chromium:575167
LOG=Y

Review URL: https://codereview.chromium.org/1692173002

Cr-Commit-Position: refs/heads/master@{#33978}

R=ahaas@chromium.org,jfb@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1661713003

Cr-Commit-Position: refs/heads/master@{#33702}

R=ahaas@chromium.org,bradnelson@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1637923002

Cr-Commit-Position: refs/heads/master@{#33541}

R=ahaas@chromium.org,bradnelson@chromium.org
LOG=Y
BUG=chromium:575167

Review URL: https://codereview.chromium.org/1608743006

Cr-Commit-Position: refs/heads/master@{#33411}

R=bradnelson@chromium.org, ahaas@chromium.org
LOG=Y
BUG=chromium:575372

Review URL: https://codereview.chromium.org/1573213002

Cr-Commit-Position: refs/heads/master@{#33366}

Make WasmModule free it's own memory, avoid mixing stack and
heap allocations in tests. This fixes several memory leaks.

Fix several signed compare issues.
Fix several floating point warnings.

Don't setup heap as external, as then the GC can't collect it.

Disable some tests that fail under ASAN.

R=ahaas@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1538543002

Cr-Commit-Position: refs/heads/master@{#32948}

As discussed in person, this adds the code from v8-native-prototype into
V8 proper, guarded by GYP flags that do not build the code by default.
Passing wasm=on to 'make' or setting v8_wasm as a GYP flag activates
building of this code.

An additional header file is added to and exported from the compiler
directory, src/compiler/wasm-compiler.h. This exposes a limited interface
with opaque Node and Graph types to the decoder to build TF graphs, as
well as functions to compile WASM graphs.

The mjsunit tests added are blacklisted because they fail without the
WASM object exposed to JS, which is also disabled by the build config
option.

This corresponds closely to https://github.com/WebAssembly/v8-native-prototype/commit/5981e06ebc9b1e578831d03100f17ebb77970ee0, with some formatting fixes and moving some files into src/compiler.

R=mstarzinger@chromium.org, bradnelson@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1504713014

Cr-Commit-Position: refs/heads/master@{#32794}