RFR(S): 8202399:) [C1] LIRGenerator::do_CheckCast needs to exclude is_invokespecial_receiver_check() when using PatchAlot

[David Holmes]

Testing completed. No issues.

David

On 30/04/2018 1:03 PM, David Holmes wrote:
> Bug: https://bugs.openjdk.java.net/browse/JDK-8202399
> webrev: http://cr.openjdk.java.net/~dholmes/8202399/webrev/
> 
> JDK-8168699 introduced  a special case for 
> is_invokespecial_receiver_check() in LIRGenerator::do_CheckCast:
> 
>    } else if (x->is_invokespecial_receiver_check()) {
>      assert(patching_info == NULL, "can't patch this");
>      stub = new DeoptimizeStub(info_for_exception,
>                                Deoptimization::Reason_class_check,
>                                Deoptimization::Action_none);
> 
> but overlooked a potential bad interaction with PatchAlot. This can lead 
> to  the assertion failure as observed during testing for JDK-8200167 
> with Graal. The proposed fix (supplied by Vladimir) is quite simple but 
> needs to be applied to each of the CPU specific files:
> 
> diff --git a/src/hotspot/cpu/x86/c1_LIRGenerator_x86.cpp 
> b/src/hotspot/cpu/x86/c1_LIRGenerator_x86.cpp
> --- a/src/hotspot/cpu/x86/c1_LIRGenerator_x86.cpp
> +++ b/src/hotspot/cpu/x86/c1_LIRGenerator_x86.cpp
> @@ -1314,7 +1314,7 @@
>      LIRItem obj(x->obj(), this);
> 
>      CodeEmitInfo* patching_info = NULL;
> -  if (!x->klass()->is_loaded() || (PatchALot && 
> !x->is_incompatible_class_change_check())) {
> +  if (!x->klass()->is_loaded() || (PatchALot && 
> !x->is_incompatible_class_change_check() && 
> !x->is_invokespecial_receiver_check())) {
> 
> Testing:
>   - hotspot/jtreg/compiler (complete)
>   - hs-comp-precheckin (once mach5 is available)
> 
> Thanks,
> David