2046867 - Align RISCV64 label tracking with the ARM64 implementation

Status: RESOLVED FIXED

(Core :: JavaScript Engine: JIT, task)

Description

[André Bargull [:anba]]

Change the RISCV64 code which tracks unbound labels to match the ARM64 implementation.

Comment 1

[André Bargull [:anba]]

Attachment: Bug 2046867 - Part 1: Remove (almost) unused Label-based branch methods. r=jandem!

Replacing the bnez(Register,Label*) call in RoundHelper allows to remove all
branch methods which take a Label* argument. This ensures all branches are
constructed through MacroAssemblerRiscv64, which takes care to properly compute
the correct offsets and disallow constant pools when necessary.

Comment 2

[André Bargull [:anba]]

Attachment: Bug 2046867 - Part 2: Remove unreachable case statements from jump-chain methods. r=jandem!

These case statements were copied from V8, but don't apply to our implementation.

Drive-by change:

• Inline UNIMPLEMENTED_RISCV

Comment 3

[André Bargull [:anba]]

Attachment: Bug 2046867 - Part 3: Move common code into an internal branchOffset method. r=jandem!

This avoids duplicating the same code in two methods.

Comment 4

[André Bargull [:anba]]

Attachment: Bug 2046867 - Part 4: Remove 'Helper' suffix from branchOffset method names. r=jandem!

Rename the methods to simply branchOffset. Short range branches take an additional
OffsetSize parameter to describe the kind of short range branch.

Comment 5

[André Bargull [:anba]]

Attachment: Bug 2046867 - Part 5: Copy some comments from ARM64. r=jandem!

Comment 6

[André Bargull [:anba]]

Attachment: Bug 2046867 - Part 6: Align Assembler::retarget with ARM64. r=jandem!

The previous code always executed the MOZ_CRASH.

Comment 7

[André Bargull [:anba]]

Attachment: Bug 2046867 - Part 7: Align Assembler::bind with ARM64. r=jandem!

Comment 8

[André Bargull [:anba]]

Attachment: Bug 2046867 - Part 8: Remove label cache and align remaining code with ARM64. r=jandem!

Branches are now only encoded in the linked list through the Label, exactly
like how the ARM64 code works.

Comment 9

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/c31a35cde647
https://hg.mozilla.org/integration/autoland/rev/3e2ab52a689d
Part 1: Remove (almost) unused Label-based branch methods. r=jandem
https://github.com/mozilla-firefox/firefox/commit/86b6f406dd10
https://hg.mozilla.org/integration/autoland/rev/ee6b9295f198
Part 2: Remove unreachable case statements from jump-chain methods. r=jandem
https://github.com/mozilla-firefox/firefox/commit/41dfed319cbe
https://hg.mozilla.org/integration/autoland/rev/345da95f3b1d
Part 3: Move common code into an internal branchOffset method. r=jandem
https://github.com/mozilla-firefox/firefox/commit/6a5098c97c49
https://hg.mozilla.org/integration/autoland/rev/c6c1e7e02a39
Part 4: Remove 'Helper' suffix from branchOffset method names. r=jandem
https://github.com/mozilla-firefox/firefox/commit/594ca197cd38
https://hg.mozilla.org/integration/autoland/rev/c7dc472a0f1c
Part 5: Copy some comments from ARM64. r=jandem
https://github.com/mozilla-firefox/firefox/commit/46b81b24fe24
https://hg.mozilla.org/integration/autoland/rev/93c640237d19
Part 6: Align Assembler::retarget with ARM64. r=jandem
https://github.com/mozilla-firefox/firefox/commit/47a2ca855cfc
https://hg.mozilla.org/integration/autoland/rev/76c33e55dace
Part 7: Align Assembler::bind with ARM64. r=jandem
https://github.com/mozilla-firefox/firefox/commit/793b7291b56f
https://hg.mozilla.org/integration/autoland/rev/b0ad2052a167
Part 8: Remove label cache and align remaining code with ARM64. r=jandem

Comment 10

[amarc]

https://hg.mozilla.org/mozilla-central/rev/3e2ab52a689d
https://hg.mozilla.org/mozilla-central/rev/ee6b9295f198
https://hg.mozilla.org/mozilla-central/rev/345da95f3b1d
https://hg.mozilla.org/mozilla-central/rev/c6c1e7e02a39
https://hg.mozilla.org/mozilla-central/rev/c7dc472a0f1c
https://hg.mozilla.org/mozilla-central/rev/93c640237d19
https://hg.mozilla.org/mozilla-central/rev/76c33e55dace
https://hg.mozilla.org/mozilla-central/rev/b0ad2052a167