RFR: 8145270: Need to eagerly initialize JVMCI compiler under -Xcomp

[Doug Simon]

I was tempted to do that myself but opted for keeping the patch minimal. However, the solution that propagates the exception is obviously better.

> On 14 Dec 2015, at 22:24, Christian Thalinger <christian.thalinger at oracle.com> wrote:
> 
> 
>> On Dec 13, 2015, at 11:49 AM, Doug Simon <doug.simon at oracle.com> wrote:
>> 
>> In blocking compilation mode (i.e., -UseInterpreter), certain compilations are forced to be non-blocking if a JVMCI compiler is being used (i.e., +UseJVMCICompiler). This is to prevent deadlocks than can occur between an application thread and a JVMCI compiler thread. One condition for forcing a compilation to be non-blocking is if the JVMCI compiler not yet initialized. This is problematic for tests that attempt to force a method to be compiled by JVMCI (e.g., -XX:+UnlockExperimentalVMOptions -XX:+EnableJVMCI -XX:+UseJVMCICompiler -XX:-TieredCompilation -Xcomp -XX:CompileCommand=compileonly,Tester_*::*). If the test is small enough, JVMCI initialization (which is lazy) may still be executing when the test methods are scheduled to be compiled. 
>> 
>> The solution is to make JVMCI compiler initialization eager in blocking compilation mode.
>> 
>> https://bugs.openjdk.java.net/browse/JDK-8145270
>> http://cr.openjdk.java.net/~dnsimon/8145270/
> 
> Looks good.  The only comment I have is at that point in initialization we can handle exceptions already and I think we should.  This gives us even useful stack traces:
> 
> Error occurred during initialization of VM
> java.lang.Error: just testing
> 	at jdk.vm.ci.hotspot.HotSpotJVMCIRuntime.getCompiler(HotSpotJVMCIRuntime.java:181)
> 
> Here is the updated patch:
> 
> diff -r d84bd22ab531 src/share/vm/compiler/compileBroker.cpp
> --- a/src/share/vm/compiler/compileBroker.cpp	Wed Dec 09 14:54:40 2015 +0100
> +++ b/src/share/vm/compiler/compileBroker.cpp	Mon Dec 14 12:20:18 2015 -1000
> @@ -56,6 +56,7 @@
> #if INCLUDE_JVMCI
> #include "jvmci/jvmciCompiler.hpp"
> #include "jvmci/jvmciRuntime.hpp"
> +#include "jvmci/jvmciJavaClasses.hpp"
> #include "runtime/vframe.hpp"
> #endif
> #ifdef COMPILER2
> @@ -498,7 +499,7 @@ CompilerCounters::CompilerCounters() {
> // CompileBroker::compilation_init
> //
> // Initialize the Compilation object
> -void CompileBroker::compilation_init() {
> +void CompileBroker::compilation_init(TRAPS) {
>   _last_method_compiled[0] = '\0';
> 
>   // No need to initialize compilation system if we do not use it.
> @@ -529,6 +530,17 @@ void CompileBroker::compilation_init() {
>       } else {
>         c1_count = JVMCIHostThreads;
>       }
> +
> +      if (!UseInterpreter) {
> +        // Force initialization of JVMCI compiler otherwise JVMCI
> +        // compilations will not block until JVMCI is initialized
> +        ResourceMark rm;
> +        TempNewSymbol getCompiler = SymbolTable::new_symbol("getCompiler", CHECK);
> +        TempNewSymbol sig = SymbolTable::new_symbol("()Ljdk/vm/ci/runtime/JVMCICompiler;", CHECK);
> +        Handle jvmciRuntime = JVMCIRuntime::get_HotSpotJVMCIRuntime(CHECK);
> +        JavaValue result(T_OBJECT);
> +        JavaCalls::call_virtual(&result, jvmciRuntime, HotSpotJVMCIRuntime::klass(), getCompiler, sig, CHECK);
> +      }
>     }
>   }
> #endif // INCLUDE_JVMCI
> diff -r d84bd22ab531 src/share/vm/compiler/compileBroker.hpp
> --- a/src/share/vm/compiler/compileBroker.hpp	Wed Dec 09 14:54:40 2015 +0100
> +++ b/src/share/vm/compiler/compileBroker.hpp	Mon Dec 14 12:20:18 2015 -1000
> @@ -276,7 +276,7 @@ public:
>     CompileQueue *q = compile_queue(comp_level);
>     return q != NULL ? q->size() : 0;
>   }
> -  static void compilation_init();
> +  static void compilation_init(TRAPS);
>   static void init_compiler_thread_log();
>   static nmethod* compile_method(const methodHandle& method,
>                                  int osr_bci,
> diff -r d84bd22ab531 src/share/vm/runtime/thread.cpp
> --- a/src/share/vm/runtime/thread.cpp	Wed Dec 09 14:54:40 2015 +0100
> +++ b/src/share/vm/runtime/thread.cpp	Mon Dec 14 12:20:18 2015 -1000
> @@ -3628,7 +3628,7 @@ jint Threads::create_vm(JavaVMInitArgs* 
> 
>   // initialize compiler(s)
> #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK) || INCLUDE_JVMCI
> -  CompileBroker::compilation_init();
> +  CompileBroker::compilation_init(CHECK_JNI_ERR);
> #endif
> 
>   // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
>