The wasm serialization format only contains TurboFan code. All other
functions are only represented by placeholders. With this CL
serialization fails if the serialized module does not contain any
TurboFan functions and would therefore consist only of placeholders.
This is a defense in depth approach, because ideally serialization
only gets triggered when TurboFan code is available. However, in some
scenarios like debugging it can happen that modules without TurboFan
code get serialized.
Bug: v8:12281
Change-Id: Ib05430ff89eb2317da80fc0d086ce1d7ab0e919d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3212510
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/main@{#77715}
The function index encoded into the serialized module is already offset
by num_imported_functions. For lazy compilation, however, we added the
number of imported functions another time, which was incorrect.
R=clemensb@chromium.org
Change-Id: I56380e21e74b4d1935ebdbab6ef8cc388de49f2c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3172761
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/main@{#76965}
The original CL was flaky because deserialization did not wait correctly
for the compilation of missing functions to finish. The baseline-finished
event was set even when there were still some functions missing. The
combination of deserialization and lazy compilation was also not handled
correctly.
Original change's description:
> [wasm] Support partial serialization of modules
>
> At the moment a WebAssembly module can be serialized successfully when
> all functions were compiled with TurboFan. However, for some functions
> it may not be necessary to be compiled with TurboFan, e.g. for functions
> where Liftoff code is as good as TurboFan code.
>
> With this CL we allow WebAssembly modules to get serialized even when
> not all functions are compiled with TurboFan. Missing functions are
> marked as missing in the serlialization. Upon deserialization, missing
> functions either get compiled by Liftoff, or initialized with a
> lazy-compilation stub, depending on the V8 configuration.
>
> Bug: v8:11862
Change-Id: I79a9e8e14199cff87fce6ae41a87087e047bbc65
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3060485
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#76017}
