1740053 - Clean-up type definitions for VMFunctions

Status: RESOLVED FIXED

(Core :: JavaScript Engine: JIT, task, P1)

Description

[André Bargull [:anba]]

• TypeToDataType has specialisations for handles, which seems dubious because TypeToDataType is only used for return types and we never return handles.
• There's quite a bit of repetition in TypeToDataType and TypeToArgProperties for gc::Cell types.
• RootType::RootFunction doesn't seem to be necessary as a distinct type. RootType::RootObject should work just fine for TypeToRootType<HandleFunction>.
• ...

Comment 1

[André Bargull [:anba]]

Attachment: Bug 1740053 - Part 1: Remove Handle and MutableHandle specialisations from TypeToDataType. r=jandem!

TypeToDataType is only used for return types and because neither Handle nor
MutableHandle are valid return types, we don't need to provide TypeToDataType
specialisations for these types.

Comment 2

[André Bargull [:anba]]

Attachment: Bug 1740053 - Part 2: Remove duplication in TypeToDataType when returning pointers to GC cells. r=jandem!

If we default to returning Type_Object for gc::Cell pointers, we can avoid some code duplication.

Depends on D130650

Comment 3

[André Bargull [:anba]]

Attachment: Bug 1740053 - Part 3: Rename "TypeToDataType" to "ReturnTypeToDataType". r=jandem!

This should make it more obvious that this struct is only needed for return types.

Depends on D130651

Comment 4

[André Bargull [:anba]]

Attachment: Bug 1740053 - Part 4: Remove duplication in TypeToArgProperties for handles to GC cells. r=jandem!

Similar to the changes in part 2.

Depends on D130652

Comment 5

[André Bargull [:anba]]

Attachment: Bug 1740053 - Part 5: Fix a comment. r=jandem!

Depends on D130653

Comment 6

[André Bargull [:anba]]

Attachment: Bug 1740053 - Part 6: Remove RootType::RootFunction. r=jandem!

RootFunction doesn't seem to provide any benefits when compared to using RootObject.
TraceRoot(JSFunction**) calls gc::ConvertToBase(), which casts JSFunction down
to JSObject.

Depends on D130654

Comment 7

[André Bargull [:anba]]

Attachment: Bug 1740053 - Part 7: Automatically derive root type from trace kind. r=jandem!

Depends on D130655

Comment 8

[André Bargull [:anba]]

Attachment: Bug 1740053 - Part 8: Remove duplication in OutParamToDataType. r=jandem!

• Add a general specialisation for pointers to pointers (Type_Pointer).
• Add a general specialisation for MutableHandle (Type_Handle).

Depends on D130656

Comment 9

[André Bargull [:anba]]

Attachment: Bug 1740053 - Part 9: Prevent OutParamToDataType from making an input param to an implicit output param. r=jandem!

This prevents making a VM function which uses for example JS::BigInt* as an
out-param. This isn't valid because JS::BigInt* is already used by other VM
functions as an input parameter.

Depends on D130657

Comment 10

[André Bargull [:anba]]

Attachment: Bug 1740053 - Part 10: Use the type system to differentiate between input and output parameters. r=jandem!

A const pointer can't be an out-param, so when we change the VM functions which
use JS::BigInt* as the last parameter to instead use const JS::BigInt*, we
no longer have to worry about conflicts between in- and out-parameters.

Depends on D130658

Comment 11

[André Bargull [:anba]]

Attachment: Bug 1740053 - Part 11: Use the type system for uint8_t* trailing parameters. r=jandem!

Similar to the changes in part 10.

Depends on D130659

Comment 12

[André Bargull [:anba]]

Attachment: Bug 1740053 - Part 12: Rename DataType::Type_Object to Type_Cell. r=jandem!

Type_Object is also used for non-object types, like strings, symbols, and
bigints. Rename it to Type_Cell to indicate that also non-objec types are
possible. The name Type_Cell was chosen to match RootType::RootCell.

Comment 13

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/68264fdb6723
Part 1: Remove Handle and MutableHandle specialisations from TypeToDataType. r=jandem
https://hg.mozilla.org/integration/autoland/rev/6358f32ec818
Part 2: Remove duplication in TypeToDataType when returning pointers to GC cells. r=jandem
https://hg.mozilla.org/integration/autoland/rev/6b78ae6c6381
Part 3: Rename "TypeToDataType" to "ReturnTypeToDataType". r=jandem
https://hg.mozilla.org/integration/autoland/rev/4d819830b0f1
Part 4: Remove duplication in TypeToArgProperties for handles to GC cells. r=jandem
https://hg.mozilla.org/integration/autoland/rev/ca48cdb63ce6
Part 5: Fix a comment. r=jandem
https://hg.mozilla.org/integration/autoland/rev/069fd355ef6b
Part 6: Remove RootType::RootFunction. r=jandem
https://hg.mozilla.org/integration/autoland/rev/f628d5ce0d33
Part 7: Automatically derive root type from trace kind. r=jandem
https://hg.mozilla.org/integration/autoland/rev/2706136fedf7
Part 8: Remove duplication in OutParamToDataType. r=jandem
https://hg.mozilla.org/integration/autoland/rev/9a9d8e431e4e
Part 9: Prevent OutParamToDataType from making an input param to an implicit output param. r=jandem
https://hg.mozilla.org/integration/autoland/rev/f3300f17ce4e
Part 10: Use the type system to differentiate between input and output parameters. r=jandem
https://hg.mozilla.org/integration/autoland/rev/31b721186d70
Part 11: Use the type system for uint8_t* trailing parameters. r=jandem
https://hg.mozilla.org/integration/autoland/rev/3731bfaca711
Part 12: Rename DataType::Type_Object to Type_Cell. r=jandem

Comment 14

[Cristina Cozmuta (:CrissCozmuta)]

https://hg.mozilla.org/mozilla-central/rev/68264fdb6723
https://hg.mozilla.org/mozilla-central/rev/6358f32ec818
https://hg.mozilla.org/mozilla-central/rev/6b78ae6c6381
https://hg.mozilla.org/mozilla-central/rev/4d819830b0f1
https://hg.mozilla.org/mozilla-central/rev/ca48cdb63ce6
https://hg.mozilla.org/mozilla-central/rev/069fd355ef6b
https://hg.mozilla.org/mozilla-central/rev/f628d5ce0d33
https://hg.mozilla.org/mozilla-central/rev/2706136fedf7
https://hg.mozilla.org/mozilla-central/rev/9a9d8e431e4e
https://hg.mozilla.org/mozilla-central/rev/f3300f17ce4e
https://hg.mozilla.org/mozilla-central/rev/31b721186d70
https://hg.mozilla.org/mozilla-central/rev/3731bfaca711