Re: JVM Interpreter
Thanks you guys. I will try not to run junk into channel and you guys promise
to stay well run. Ok.
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From: Kim Barrett
Sent: Saturday, August 25, 2018 11:47:41 PM
To: mr rupplin
Cc: core-libs-dev@openjdk.java.net
Subject: Re: JVM Interpreter
> On Aug 25, 2018, at 2:39 PM, mr rupplin wrote:
>
> I am presuming the JVM interpreter is defined/implemented in the the hotspot
> module since this is a JVM implementation.
This is probably more of a hotspot-dev or hotspot-runtime-dev kind of question,
rather than core-libs.
> I cannot seem to find *any* instruction in it that gets called by a simple
> "./java -ea Class" call. We are stumped.
>
>
> For instance there are methods for local set and reference:
>
>
> void BytecodeInterpreter::set_stack_slot(intptr_t *tos, address value, int
> offset) {
>
>*((address *)&tos[Interpreter::expr_index_at(-offset)]) = value;
> }
>
> void BytecodeInterpreter::set_stack_object(intptr_t *tos, oop value, int
> offset) {
>
> *((oop *)&tos[Interpreter::expr_index_at(-offset)]) = value;
> }
>
> These (and similar in same file) are not being called at all during the JVM
> interpreter phase (simple java program as reference). My program creates an
> object and calls a test method with a single object as reference.
>
> What could be the hang up? No printf statement seems to work.
I think BytecodeInterpreter is part of CppInterpreter, which I think
is only used by Zero platforms, with the TemplateInterpreter used by
all other platforms. So unless you are running on a platform that
uses Zero, or specifically built for Zero, I think BytecodeInterpreter
won't be used (and might not even be compiled in?).
> Thanks.
>
> Max Rupplin
>
> Software Engineer
Re: JVM Interpreter
On 08/25/2018 07:39 PM, mr rupplin wrote: > I am presuming the JVM interpreter is defined/implemented in the the > hotspot module since this is a JVM implementation. That's right. > I cannot seem to find *any* instruction in it that gets called by a > simple "./java -ea Class" call. We are stumped. On the "teach a man to fish" priniple, here goes. On most systems the interpreter is written in assembly language and generated at runtime. Put a GDB breakpoint here in javaCalls.cpp:: StubRoutines::call_stub()( (address)&link, // (intptr_t*)&(result->_value), // see NOTE above (compiler problem) result_val_address, // see NOTE above (compiler problem) result_type, method(), entry_point, args->parameters(), args->size_of_parameters(), CHECK ); Step in from the call stub. You'll need to use "si" rather than "step", because this is not C++, it's pure hand-crafted assembly language: the real thing. You'll see the registers saved, the parameters copied into the interpreter stack, and the interpreter entered. -- Andrew Haley Java Platform Lead Engineer Red Hat UK Ltd. <https://www.redhat.com> EAC8 43EB D3EF DB98 CC77 2FAD A5CD 6035 332F A671
Re: JVM Interpreter
> On Aug 25, 2018, at 2:39 PM, mr rupplin wrote:
>
> I am presuming the JVM interpreter is defined/implemented in the the hotspot
> module since this is a JVM implementation.
This is probably more of a hotspot-dev or hotspot-runtime-dev kind of question,
rather than core-libs.
> I cannot seem to find *any* instruction in it that gets called by a simple
> "./java -ea Class" call. We are stumped.
>
>
> For instance there are methods for local set and reference:
>
>
> void BytecodeInterpreter::set_stack_slot(intptr_t *tos, address value, int
> offset) {
>
>*((address *)&tos[Interpreter::expr_index_at(-offset)]) = value;
> }
>
> void BytecodeInterpreter::set_stack_object(intptr_t *tos, oop value, int
> offset) {
>
> *((oop *)&tos[Interpreter::expr_index_at(-offset)]) = value;
> }
>
> These (and similar in same file) are not being called at all during the JVM
> interpreter phase (simple java program as reference). My program creates an
> object and calls a test method with a single object as reference.
>
> What could be the hang up? No printf statement seems to work.
I think BytecodeInterpreter is part of CppInterpreter, which I think
is only used by Zero platforms, with the TemplateInterpreter used by
all other platforms. So unless you are running on a platform that
uses Zero, or specifically built for Zero, I think BytecodeInterpreter
won't be used (and might not even be compiled in?).
> Thanks.
>
> Max Rupplin
>
> Software Engineer
JVM Interpreter
I am presuming the JVM interpreter is defined/implemented in the the hotspot
module since this is a JVM implementation.
I cannot seem to find *any* instruction in it that gets called by a simple
"./java -ea Class" call. We are stumped.
For instance there are methods for local set and reference:
void BytecodeInterpreter::set_stack_slot(intptr_t *tos, address value, int
offset) {
*((address *)&tos[Interpreter::expr_index_at(-offset)]) = value;
}
void BytecodeInterpreter::set_stack_object(intptr_t *tos, oop value, int
offset) {
*((oop *)&tos[Interpreter::expr_index_at(-offset)]) = value;
}
These (and similar in same file) are not being called at all during the JVM
interpreter phase (simple java program as reference). My program creates an
object and calls a test method with a single object as reference.
What could be the hang up? No printf statement seems to work.
Thanks.
Max Rupplin
Software Engineer
