RFR: 8306579: Consider building with /Zc:throwingNew

[Phil Race]

On Tue, 12 Nov 2024 14:30:05 GMT, Julian Waters <jwaters at openjdk.org> wrote:

> [JDK-8305590](https://bugs.openjdk.org/browse/JDK-8305590) removed `-fcheck-new` when building with gcc. It turns out Visual Studio has a similar option, though inverted in behavior and default.
> 
> It seems like /Zc:throwingNew- (the default) corresponds to gcc -fcheck-new, and /Zc:throwingNew corresponds to -fno-check-new (the default).
> 
> The Visual Studio documentation strongly recommends using /Zc:throwingNew if possible, as turning it off (the default) seriously bloats code and inhibits optimizations.
> https://learn.microsoft.com/en-us/cpp/build/reference/zc-throwingnew-assume-operator-new-throws?view=msvc-170
> 
> As mentioned in [JDK-8305590](https://bugs.openjdk.org/browse/JDK-8305590), the standard says that an allocation function can report allocation failure either by returning null (when it must have a nothrow exception specification), or by throwing `std::bad_alloc` (so obviously must not be declared as non-throwing). HotSpot allocation functions terminate the program instead of throwing on allocation failure, so similarly don't need the result checked for null.
> 
> The documentation for /Zc:throwingNew is somewhat vague and confusing, so some investigation is probably needed to verify it really has the desired effect for us.

src/java.desktop/windows/native/libawt/windows/awt_new.cpp line 127:

> 125: }
> 126: #endif
> 127: 

I don't see you commenting on this which is a "huge" deal as it seems like it changes memory allocation for a lot of the AWT Windows code.
This needs careful and analysis and explanation - from you - so reviewers can ponder it.
Also you need to run a lot of tests to verify it.

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PR Review Comment: https://git.openjdk.org/jdk/pull/22039#discussion_r1845299072