1665946 - Handle Strings and null/undefined in CacheIR bitwise operations

Status: RESOLVED FIXED

(Core :: JavaScript Engine: JIT, task, P2)

Description

[André Bargull [:anba]]

We don't have CacheIR support for string|0, because it's already supported by Ion. For Warp we need to handle this at the CacheIR level. The same goes for null and undefined, which I've seen in user code like int32Array[invalidIndex] | 0 (bug 1515620).

Comment 1

[André Bargull [:anba]]

Attachment: Bug 1665946 - Part 1: Handle null and undefined in CacheIR binary bit-ops. r=jandem!

Handle null and undefined to avoid the slow VM-call fallback for code like
int32Array[invalidIndex]|0 (bug 1515620).

Comment 2

[André Bargull [:anba]]

Attachment: Bug 1665946 - Part 2: Handle Strings in CacheIR binary bit-ops. r=jandem!

string|0 is sometimes used as a "fast" way to convert strings to integers.
Ion handles this case, but Warp doesn't yet.

Depends on D90712

Comment 3

[André Bargull [:anba]]

Attachment: Bug 1665946 - Part 3: Extract CanTruncateToInt32 and TruncateToInt32Guard functions. r=jandem!

Extract the CanTruncateToInt32 and EmitTruncateToInt32Guard functions in
preparation for the next part.

Depends on D90713

Comment 4

[André Bargull [:anba]]

Attachment: Bug 1665946 - Part 4: Align CacheIR unary with binary bit-ops. r=jandem!

Use the same approach as taken for binary bitwise operations. This ensures no
unexpected performance differences can happen when switching between binary
and unary operations. This change also removes unreachable code in
UnaryArithIRGenerator::tryAttachStringNumber(): If the input is a string,
we always succeed in tryAttachStringInt32(), so the JSOp::BitNot case in
tryAttachStringNumber() is never taken. Furthermore this avoids attaching
the same stub multiple times in tryAttachStringInt32() when the string can't
be parsed as an int32 (e.g. ~"1.1").

Depends on D90714

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/657a08a46195
Part 1: Handle null and undefined in CacheIR binary bit-ops. r=jandem
https://hg.mozilla.org/integration/autoland/rev/c7fe96c53e6f
Part 2: Handle Strings in CacheIR binary bit-ops. r=jandem
https://hg.mozilla.org/integration/autoland/rev/bb9a4a6710d1
Part 3: Extract CanTruncateToInt32 and TruncateToInt32Guard functions. r=jandem
https://hg.mozilla.org/integration/autoland/rev/1fc515ba6237
Part 4: Align CacheIR unary with binary bit-ops. r=jandem

Comment 6

[Dorel Luca [:dluca]]

https://hg.mozilla.org/mozilla-central/rev/657a08a46195
https://hg.mozilla.org/mozilla-central/rev/c7fe96c53e6f
https://hg.mozilla.org/mozilla-central/rev/bb9a4a6710d1
https://hg.mozilla.org/mozilla-central/rev/1fc515ba6237