RFR: JDK-8300531: MSVC CFlags look suspicious [v8]

[Justin King]

On Tue, 14 Feb 2023 18:42:07 GMT, Justin King <jcking at openjdk.org> wrote:

>> Update MSVC CFlags to be more consistent with other compilers. Also disables RTTI in a simliar manner to GCC/Clang for the JVM.
>
> Justin King has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Reposition -Oy-
>   
>   Signed-off-by: Justin King <jcking at google.com>

The main difference between `/O1` and `/O2`, besides speed vs. size, is that the latter adds `/Oi` which tells the compiler to try and inline intrinsics rather than making function calls. This can lead to improved speed. GCC/Clang do the same thing by treating certain functions like memcpy/memset/memmove and special.

Additionally I added `/Oy-` which preserves frame pointers. This makes MSVC match the GCC/Clang configuration with pass `-fno-omit-frame-pointer`.

Additionally we have disabled RTTI now by passing `/GR-`, this again matches GCC/Clang. The resulting size of the JVM binary drops by ~1MB.

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PR: https://git.openjdk.org/jdk/pull/12073