RFR: 8276314: [JVMCI] check alignment of call displacement during code installation

[Vladimir Kozlov]

On Tue, 2 Nov 2021 21:31:25 GMT, Doug Simon <dnsimon at openjdk.org> wrote:

> This PR add verification of code alignment invariants related to x64 call instructions during code installation.
> This in turn allows a JVMCI compilation that generates a misaligned call to fail gracefully (i.e. bailout) instead of the VM crashing when it checks alignment before patching the displacement of a call instruction.

src/hotspot/cpu/x86/jvmciCodeInstaller_x86.cpp line 191:

> 189:     }
> 190:     default:
> 191:       JVMCI_ERROR("invalid _next_call_type value");

May be print `%d` invalid call type here too since you are changing code around.

src/hotspot/cpu/x86/jvmciCodeInstaller_x86.cpp line 194:

> 192:       return;
> 193:   }
> 194:   if (os::is_MP() && !call->is_displacement_aligned()) {

You are checking for `MP` in current era? Why not always require alignment?

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PR: https://git.openjdk.java.net/jdk/pull/6218