RFR: 8258838: Remove JVM option UseStackBanging [v2]

[Vladimir Kozlov]

On Fri, 8 Jan 2021 14:41:12 GMT, Harold Seigel <hseigel at openjdk.org> wrote:

>> Please review this change to remove the JVM develop flag UseStackBanging and always use stack banging.
>> 
>> The change was tested with tiers 1-2 on Linux, Mac OS, and Windows, tiers 3-5 on Linux x64, and cross-builds on PPC64, Linux32, and S390x.
>> 
>> Thanks, Harold
>
> Harold Seigel has updated the pull request incrementally with one additional commit since the last revision:
> 
>   fix copyrights, other minot changes

src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.hotspot/src/org/graalvm/compiler/hotspot/GraalHotSpotVMConfig.java line 256:

> 254:     public final int stackShadowPages = getFlag("StackShadowPages", Integer.class);
> 255:     public final int stackReservedPages = getFlag("StackReservedPages", Integer.class, 0, JDK >= 9);
> 256:     public final int stackBias = getConstant("STACK_BIAS", Integer.class, 0, JDK < 15);

The line should be modified instead of removal:
public final boolean useStackBanging = getFlag("UseStackBanging", Boolean.class, true, JDK < 17);
@dougxc please note that it should be upstreamed when GraalVM adopt JDK 17.

src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.hotspot/src/org/graalvm/compiler/hotspot/HotSpotHostBackend.java line 133:

> 131: 
> 132:     public void emitStackOverflowCheck(CompilationResultBuilder crb) {
> 133:         // Each code entry causes one stack bang n pages down the stack where n

I think you can leave this file unchanged with my suggested modification in GraalHotSpotVMConfig.java.

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PR: https://git.openjdk.java.net/jdk/pull/1988