This patch is a bit unfortunate, in the sense that it exposes some of
the JIT guts to the rest of the VM. Code needs to treat "machine return
addresses" as valid if non-NULL (as before) and also not equal to a
tier-down trampoline. This is because tier-down at a return needs the
old frame pointer to load the "virtual return address", and the way this
patch works is that it passes the vra in a well-known register. It's a
custom calling convention for a certain kind of return.
* libguile/jit.h (scm_jit_return_to_interpreter_trampoline): New
internal global.
* libguile/jit.c: (scm_jit_clear_mcode_return_addresses): Move here,
from vm.c. Instead of zeroing return addresses, set them to the
return-to-interpreter trampoline.
* libguile/vm-engine.c (return-values): Don't enter mcode if the mra is
scm_jit_return_to_interpreter_trampoline.
* libguile/vm.c (capture_continuation): Treat the tier-down trampoline
as NULL.
* libguile/vm-engine.c (instrument-entry, instrument-loop): Make the
counter check >=, so that we can set the threshold to 0 and still get
compilation.
* libguile/jit.h (enum scm_jit_counter_value): Make the increments
event.
* libguile/jit.c (scm_jit_counter_threshold): Make a static variable
instead of a compile-time constant.
(scm_init_jit): Init scm_jit_counter_threshold from
GUILE_JIT_COUNTER_THRESHOLD environment variable. Default is -1
indicating "never JIT".
* libguile/vm-engine.c (instrument-entry, instrument-loop): Adapt to new
variable.
* libguile/init.c (scm_i_init_guile): Call scm_init_jit ().
* libguile/jit.c (enter_mcode, exit_mcode): New static members; code
pointers for the JIT trampoline.
(emit_exit): New helper. The Lightning tramp/frame mechanism that we
use needs to exit via a jmp instead of a return. Adapt callers of
jit_ret.
(emit_entry_trampoline): Use the "frame" mechanism to enter the JIT.
(compile1): Add missing "break" after case statements. Oops!
(compile): Add prolog and "tramp" to compiled functions.
(initialize_jit): New local routine to init the JIT on demand.
(compute_mcode): New helper, to compile a function.
(scm_sys_jit_compile): New function, exported to Scheme as
%jit-compile.
(scm_jit_compute_mcode): Return the existing mcode if the function is
at the start.
(scm_jit_enter_mcode): Call the enter_mcode trampoline.
* libguile/jit.h (struct scm_jit_state): Declare, so we can make
pointers to it.
* libguile/threads.h (struct scm_thread): Add jit_state member.
* libguile/threads.c (on_thread_exit): Free the jit state.
* libguile/intrinsics.h (SCM_FOR_ALL_VM_INTRINSICS): Update prototype of
capture-continuation.
* libguile/jit.h:
* libguile/jit.c (scm_jit_enter_mcode): Return void, not the vra.
Instead, we expect the code to set vp->ip for the vra.
* libguile/vm-engine.c (instrument-entry, instrument-loop)
(return-values, abort): Adapt scm_jit_enter_mcode calling convention.
(capture-continuation): No need to pass an mra; the intrinsic will
read it from the stack.
* libguile/vm.c (capture_continuation): Remove mra arg, as we take mra
from the continuation.
(scm_call_n): Adapt to scm_jit_enter_mcode change.
* libguile/continuations.c (scm_i_continuation_to_frame): Adapt to vra
field renaming.
(scm_i_reinstate_continuation, grow_stack, copy_stack_and_call)
(scm_dynthrow): Take mra of continuation. Set on the vp before the
longjmp.
* libguile/continuations.h: Update scm_i_reinstate_continuation
prototype.
* libguile/dynstack.h:
* libguile/control.c (scm_suspendable_continuation_p):
* libguile/dynstack.c (PROMPT_WORDS, PROMPT_VRA, PROMPT_MRA):
(PROMPT_JMPBUF, scm_dynstack_push_prompt, scm_dynstack_find_prompt)
(scm_dynstack_wind_prompt): Store both virtual and machine return
addresses on the dynstack, for prompts.
* libguile/eval.c (eval): Pass NULL for mra.
* libguile/intrinsics.c (push_prompt): Add mra arg, and pass it to the
dynstack.
* libguile/intrinsics.h: Update prototypes so that continuation-related
intrinsics can save and restore the MRA.
* libguile/jit.h:
* libguile/jit.c: Return VRA when JIT code needs to tier down.
* libguile/stacks.c (find_prompt, scm_make_stack)
* libguile/throw.c (catch): Adapt find-prompt calls.
* libguile/vm-engine.c (instrument-entry, instrument-loop): Add logic to
continue with vcode after the mcode finishes.
(compose-continuation, capture-continuation, abort, prompt): Add logic
to pass NULL as captured MRA, but continue with mcode from new
continuations, if appropriate.
* libguile/vm.c (scm_i_vm_cont_to_frame, capture_stack)
(scm_i_capture_current_stack, reinstate_continuation_x)
(capture_continuation, compose_continuation_inner, compose_continuation)
(capture_delimited_continuation, abort_to_prompt): Adapt to plumb
around machine code continuations.
(scm_call_n): Check "mra_after_abort" field for machine code
continuation, if any.
* libguile/vm.h (struct scm_vm): Add "mra_after_abort" field.
(struct scm_vm_cont): Rename "ra" field to "vra" and add "mra" field.
* am/bootstrap.am (SOURCES):
* module/Makefile.am (SOURCES): Handle renamve of handle-interrupts.scm
to loop-instrumentation.scm.
* libguile/jit.h (SCM_JIT_COUNTER_ENTRY_INCREMENT): Rename from
SCM_JIT_COUNTER_CALL_INCREMENT.
* libguile/vm-engine.c (instrument-entry): Rename from instrument-call.
* module/language/cps/compile-bytecode.scm (compile-function): Add
handle-interrupts code before calls and returns. Compile the
"instrument-loop" primcall to an "instrument-loop" instruction and a
"handle-interrupts" instruction.
(lower-cps): Adapt to add-loop-instrumentation name change.
* module/language/cps/loop-instrumentation.scm: Rename from
handle-interrupts.scm and just add "instrument-loop" primcalls in
loops. The compiler will add handle-interrupts primcalls as
appropriate.
* module/system/vm/assembler.scm (<jit-data>): New data type, for
emitting embedded JIT data.
(<meta>): Add field for current JIT data.
(make-meta): Initialize current JIT data.
(emit-instrument-entry*, emit-instrument-loop*): New instruction
emitters that reference the current JIT data.
(end-program): Now that all labels are known, arrange to serialize the
JIT data.
(link-data): Reserve space for JIT data, and add relocs to initialize
the "start" / "end" fields.
* libguile/jit.h (struct scm_jit_function_data)
(enum scm_jit_counter_value): New data types.
* libguile/jit.c (scm_jit_compute_mcode, scm_jit_enter_mcode): New
function stubs. Adapt label/offset compilers to take pointers.
* libguile/vm-engine.c (instrument-call, instrument-loop): New
instructions.
* libguile/vm.c: Add jit.h include.
* module/system/vm/assembler.scm (emit-instrument-call)
(emit-instrument-loop): New exports.
* libguile/Makefile.am (AM_CPPFLAGS):
(libguile_@GUILE_EFFECTIVE_VERSION@_la_SOURCES): If ENABLE_JIT, build
lightning.
(EXTRA_DIST): Add lightning files.
* libguile/lightning/lightning.am (lightning_extra_files): Add COPYING
and related files to the dist.
* libguile/jit.c:
* libguile/jit.h: New files.
