RFR: 8296115: Allow for compiling the JDK with strict standards conformance [v4]

[Daniel Jeliński]

On Wed, 9 Nov 2022 12:15:28 GMT, Magnus Ihse Bursie <ihse at openjdk.org> wrote:

>> FWIW, `-permissive-` is getting less permissive with every compiler iteration; with MSVC2022 (` C Compiler:     Version 19.33.31629`) even hotspot doesn't build.
>
> @djelinski That's a bit alarming. :-/ Do you have any idea if it complains "correctly" on Hotspot by detecting fishy code that should be fixed, or if it is overly cranky and is complaining about reasonable but non-standard extensions?

@magicus that depends on how you define "cranky"; in default mode, `long` and `int` are fully interchangeable. In `permissive-`, they are [distinct types](https://learn.microsoft.com/en-us/cpp/overview/cpp-conformance-improvements-2019?view=msvc-170#overload-resolution-involving-integral-overloads-and-long-arguments). As a result, compilation of code that assumes that `jint` is equal to `int` breaks (on Windows, `jint` is typedef'd to `long`).

Example failure:

C:...\src\hotspot\share\opto\mulnode.cpp(248): error C2668: 'uabs': ambiguous call to overloaded function
C:...\src\hotspot\share\utilities/globalDefinitions.hpp(1146): note: could be 'unsigned int uabs(int)'
C:...\src\hotspot\share\utilities/globalDefinitions.hpp(1145): note: or       'julong uabs(jlong)'
C:...\src\hotspot\share\utilities/globalDefinitions.hpp(1136): note: or       'julong uabs(julong)'
C:...\src\hotspot\share\utilities/globalDefinitions.hpp(1127): note: or       'unsigned int uabs(unsigned int)'
C:...\src\hotspot\share\opto\mulnode.cpp(248): note: while trying to match the argument list '(const jint)'

FWIW, clang-cl also fails on this.

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PR: https://git.openjdk.org/jdk/pull/10912