[9] Preliminary RFR (M): Emit direct call instead of linkTo* for recursive indy/MH.invoke* calls (original) (raw)

Christian Thalinger christian.thalinger at oracle.com
Mon Mar 30 18:51:01 UTC 2015

I think it’s about time to remove this:

     guarantee(!target->is_method_handle_intrinsic(), "should not happen");  // XXX remove

I should have removed it before the initial integration :-)

On Mar 25, 2015, at 10:38 AM, Vladimir Ivanov <vladimir.x.ivanov at oracle.com> wrote:

http://cr.openjdk.java.net/~vlivanov/8072008/webrev.00 https://bugs.openjdk.java.net/browse/JDK-8072008 I'd like to get early feedback on the approach I chose. So far, only x86 is supported. Other platforms are WIP. The idea is to get rid of MH.invokeBasic/linkTo* linkers when receiver/MemberName is constant, but VM doesn't inline target method. The problem with substituting a linker call with a direct/virtual call is that call site resolution relies on bytecode info (see SharedRuntime::resolve{static,optvirtual,virtual}callC). But on bytecode level the call site refers to linker method, which is almost useless. The idea of the fix is to attach additional metadata (Method*) to the call site, so VM can use it instead of querying bytecode. The metadata is placed in relocation table (staticcall, optvirtualcall, virtualcall relocation types) and contains a Method* the call site is resolved to by JIT compiler (method from a call IR node). Example: MemberName mn = ...; // compile-time constant MethodHandle.linkToStatic(..., mn) callq 0x0000000109cb1900 ; OopMap{off=28} ; *invokestatic linkToStatic ; - Test::invokeStatic at 3 (line 108) ; {staticcall T.f1} It's call to MethodHandle.linkToStatic on bytecode level, but in generated code it's a direct call to T.f1. I enhanced diagnostic output to provide additional information call site targets when additional info is present. Also, for testing purposes, I introduced 2 new methods for whitebox testing: - WhiteBox::clearInlineCaches - WhiteBox::deoptimize Testing: JPRT, java/lang/invoke, nashorn, octane Thanks! Best regards, Vladimir Ivanov

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