1896118 - ICF detection code doesn't work correctly

Status: RESOLVED FIXED

(Firefox Build System :: General, defect, P5)

Description

[[:sergesanspaille]]

The following configure invocation shows that icf is not correctly activated when it should be:

./mach configure --enable-release --enable-linker=lld --enable-optimize | grep Folding
 0:03.62 checking whether the linker supports Identical Code Folding... no
 0:04.67 js/src> checking whether the linker supports Identical Code Folding... (cached) no

Comment 1

[[:sergesanspaille]]

Attachment: Bug 1896118 - Rework identical code folding detection check r=glandium

Otherwise the two symbols checked have different code and icf doesn't happen.

Comment 2

[BugBot [:suhaib / :marco]]

The severity field is not set for this bug.
:ahochheiden, could you have a look please?

For more information, please visit BugBot documentation.

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/81a2357443c8
Rework identical code folding detection check r=glandium

Comment 4

[Sandor Molnar[:smolnar]]

https://hg.mozilla.org/mozilla-central/rev/81a2357443c8

Comment 5

[Jeff Muizelaar [:jrmuizel]]

Does this only impact Linux? i.e. did we have ICF working on Windows?

Comment 6

[[:sergesanspaille]]

No ICF on WIndows not OSX (because of the linker used). But We should have it on Android soo (see #1899972)

Comment 7

[Mike Hommey [:glandium]]

Actually, lld has ICF support for both macho and COFF, but that's through different flags.

Comment 8

[Mike Hommey [:glandium]]

In fact, we're already enabling ICF on Windows through https://searchfox.org/mozilla-central/rev/59d854a90e036cfa77f3c5b70c8c6ef1d60ebb98/python/mozbuild/mozbuild/frontend/context.py#492
We should probably handle it similarly to what we do on Linux.