1178317 - eliminate large static constructor in ShimInterfaceInfo.cpp

Status: RESOLVED FIXED

(Core :: XPCOM, defect)

Description

[Nathan Froyd [:froydnj]]

It's silly that we have this.  Let's get rid of it.

Comment 1

[Nathan Froyd [:froydnj]]

Attachment: eliminate large static constructor from ShimInterfaceInfo.cpp

Constructing kComponentsInterfaceShimMap required a static constructor
on some compilers, due to a non-constexpr constructor and the necessity
of copying non-constexpr things like nsIID.  This static constructor is
large (several kilobytes of object code on x86-64) and completely
unnecessary.

To fix this, let's add a constexpr (well, MOZ_CONSTEXPR) constructor to
ComponentsInterfaceShimEntry.  This change alone doesn't completely
solve our problem, because the nsIID member still needs to be copied.
But doing that copying is silly: we only use the IID for constructing a
ShimInterfaceInfo in ShimInterfaceInfo::MaybeConstruct, and the
ShimInterfaceInfo constructor takes a const reference.  So let's store a
const reference in ComponentsInterfaceShimEntry, too, and make that
structure significantly smaller in the process.

Comment 2

[Biru [:poiru]]

Comment on attachment 8627230 [details] [diff] [review]
eliminate large static constructor from ShimInterfaceInfo.cpp

Review of attachment 8627230 [details] [diff] [review]:
-----------------------------------------------------------------

::: xpcom/reflect/xptinfo/ShimInterfaceInfo.cpp
@@ +280,5 @@
>  using namespace mozilla;
>  
>  struct ComponentsInterfaceShimEntry {
> +  MOZ_CONSTEXPR ComponentsInterfaceShimEntry(const char* aName, const nsIID& aIID,
> +                                             const mozilla::dom::NativePropertyHooks* aNativePropHooks)

This is a rather long line, but I guess that doesn't really matter here. Perhaps remove `mozilla::` if you feel like it.

Comment 3

[Pulsebot]

https://hg.mozilla.org/integration/mozilla-inbound/rev/bbda4b92523f

Comment 4

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/bbda4b92523f

Comment 5

[Nicholas Nethercote [inactive]]

You changed the emacs mode line but not the vim one :(

Comment 6

[Andrew McCreight [:mccr8]]

FYI I didn't change the modelines in this subdir with my script because too many files had 4-space indent or something.