2047250 - Allow disabling constant pools in AssemblerBufferWithConstantPools

Status: RESOLVED FIXED

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

Description

[André Bargull [:anba]]

Allow disabling constant pools in AssemblerBufferWithConstantPools when only branch deadlines are needed, as is the case for riscv64.

Comment 1

[André Bargull [:anba]]

Attachment: Bug 2047250 - Part 1: Improve CodeGen jit spew for constant pools in riscv64. r=jandem!

Spew the constant pool instructions in WritePoolGuard, because the guard
instruction is written after the veneer branches, even though the guard
appears earlier in the final assembly.

Comment 2

[André Bargull [:anba]]

Attachment: Bug 2047250 - Part 2: Add EmptyPool optimisation. r=jandem!

Allow to opt-out of constant pools when setting HeaderSize to zero.

This will be used in part 3 for RISCV64.

Comment 3

[André Bargull [:anba]]

Attachment: Bug 2047250 - Part 3: Set pool header size to zero for riscv64. r=jandem!

And remove functions which are no longer needed when not using constant pools.

Comment 4

[André Bargull [:anba]]

Attachment: Bug 2047250 - Part 4: Reorder fields in Pool to reduce padding. r=jandem!

Shrinks the size from 160 to 152 bytes.

Drive-by change:

• Use field initialisers when possible.

Comment 5

[André Bargull [:anba]]

Attachment: Bug 2047250 - Part 5: Add comments and remove unused code. r=jandem!

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/3be956d62b89
https://hg.mozilla.org/integration/autoland/rev/c0a89e0c1333
Part 1: Improve CodeGen jit spew for constant pools in riscv64. r=jandem
https://github.com/mozilla-firefox/firefox/commit/5cb8a5dd2c99
https://hg.mozilla.org/integration/autoland/rev/16070e47cb43
Part 2: Add EmptyPool optimisation. r=jandem
https://github.com/mozilla-firefox/firefox/commit/f331755dc3d1
https://hg.mozilla.org/integration/autoland/rev/b5ae0332729b
Part 3: Set pool header size to zero for riscv64. r=jandem
https://github.com/mozilla-firefox/firefox/commit/7a593f1adce6
https://hg.mozilla.org/integration/autoland/rev/377b5a274908
Part 4: Reorder fields in Pool to reduce padding. r=jandem
https://github.com/mozilla-firefox/firefox/commit/8e6c4d36b48f
https://hg.mozilla.org/integration/autoland/rev/bff656a57299
Part 5: Add comments and remove unused code. r=jandem

Comment 7

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/a252f3b552ab
https://hg.mozilla.org/integration/autoland/rev/2dfa91a828f3
Revert "Bug 2047250, Bug 2047249 - Part 5: Add comments and remove unused code. r=jandem" for causing build bustages at testAssemblerBuffer.cpp

Comment 8

[rperta]

Backed out for causing build bustages at testAssemblerBuffer.cpp
Backout link
Push with failures
Failure log(s)

Comment 9

[André Bargull [:anba]]

MOZ_NO_UNIQUE_ADDRESS contains a note that [[no_unique_address]] should be used for C++20, but apparently Windows builds still require [[msvc::no_unique_address]]. Switching [[no_unique_address]] to MOZ_NO_UNIQUE_ADDRESS in part 2 fixes the build error.

Comment 10

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/4baaadc67d68
https://hg.mozilla.org/integration/autoland/rev/ac9f2caa38c7
Part 1: Improve CodeGen jit spew for constant pools in riscv64. r=jandem
https://github.com/mozilla-firefox/firefox/commit/23891d6ab0ba
https://hg.mozilla.org/integration/autoland/rev/251adc40a3e9
Part 2: Add EmptyPool optimisation. r=jandem
https://github.com/mozilla-firefox/firefox/commit/a3d6eb0f1ed0
https://hg.mozilla.org/integration/autoland/rev/e56426ef9221
Part 3: Set pool header size to zero for riscv64. r=jandem
https://github.com/mozilla-firefox/firefox/commit/c6c0b5a5e398
https://hg.mozilla.org/integration/autoland/rev/961f7ec6c79a
Part 4: Reorder fields in Pool to reduce padding. r=jandem
https://github.com/mozilla-firefox/firefox/commit/2ace1e9e666e
https://hg.mozilla.org/integration/autoland/rev/79bfd02dfed2
Part 5: Add comments and remove unused code. r=jandem

Comment 11

[Sandor Molnar[:smolnar]]

https://hg.mozilla.org/mozilla-central/rev/ac9f2caa38c7
https://hg.mozilla.org/mozilla-central/rev/251adc40a3e9
https://hg.mozilla.org/mozilla-central/rev/e56426ef9221
https://hg.mozilla.org/mozilla-central/rev/961f7ec6c79a
https://hg.mozilla.org/mozilla-central/rev/79bfd02dfed2