1718102 - `CompilationInput::lazy` accesses should be replaced by accessors.

Status: RESOLVED FIXED

(Core :: JavaScript Engine, enhancement, P1)

Description

[Nicolas B. Pierron [:nbp]]

The goal is to go toward the ability to parse Lazy functions without having neither a JSFunction nor a BaseScript.

By adding wrappers on CompilationInput::lazy field, the goal is to be able to abstract the BaseScript field behind something which could use a Stencil instead.

https://searchfox.org/mozilla-central/search?q=symbol:F_%3CT_js%3A%3Afrontend%3A%3ACompilationInput%3E_lazy&redirect=false

Comment 1

[Nicolas B. Pierron [:nbp]]

Attachment: Bug 1718102 - Extract ScriptFlags accessors to be reused.

The CompilationInput currently let the consumer reach to the lazy field, to
reach accessors implemented on the BaseScript. As we are trying to remove direct
usage of the lazy field, and later abstract between a ScriptStencilExtra or a
BaseScript, we have to make it simple to add these accessors to other
structures.

This change extract the accessors and move them to a parametrized structure
which knows that its parameters is able to locate the field which contains all
these flags.

To implement accessors, on should inherit from the class
ImmutableScriptFlagsAccessors<...>

and parametrize it with the derived class as long as the derived class
implements the function

ImmutableFlags immutableFlags() const { ... }

And similarly for mutable flags, except that the returned value should be a
reference.

Comment 2

[Nicolas B. Pierron [:nbp]]

Attachment: Bug 1718102 - Abstract CompilationInput lazy fields behind accessors.

This change adds accessors to reach the BaseScript* lazy field as well as all
information taken from it. The intent being that most information used from the
BaseScript are taken out of the ScriptStencil and ScriptStencilExtra structures,
and that we can later use these in-place where the lazy field is used.

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/55372527ebed
Extract ScriptFlags accessors to be reused. r=arai
https://hg.mozilla.org/integration/autoland/rev/be090a2e202a
Abstract CompilationInput lazy fields behind accessors. r=arai

Comment 4

[Marian-Vasile Laza]

Backed out for causing bustages on JSScript.h.
Backout link
Push with failures
Failure Log

Comment 5

[Nicolas B. Pierron [:nbp]]

Attachment: Bug 1718102 - Move the jit entry out of the BaseScript.

To satisfy clang-cl field ordering, we have to extract the
BaseScript::warmUpData_ to make it live next to the inherited GC cell which
holds the jitCodeRaw pointer.

This modification is madated by assertion which is verifying that
SelfHostedLazyScript shares the same offsets as the BaseScript for jitCodeRaw
field and the warmUpData_ field.

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/9f48019d06ea
Extract ScriptFlags accessors to be reused. r=arai
https://hg.mozilla.org/integration/autoland/rev/b4978b94e605
Abstract CompilationInput lazy fields behind accessors. r=arai

Comment 7

[Natalia Csoregi [:nataliaCs]]

https://hg.mozilla.org/mozilla-central/rev/9f48019d06ea
https://hg.mozilla.org/mozilla-central/rev/b4978b94e605