Combine call info and cache to speed up method invocation

To perform a regular method call, the VM needs two structs,
`rb_call_info` and `rb_call_cache`. At the moment, we allocate these two
structures in separate buffers. In the worst case, the CPU needs to read
4 cache lines to complete a method call. Putting the two structures
together reduces the maximum number of cache line reads to 2.

Combining the structures also saves 8 bytes per call site as the current
layout uses separate two pointers for the call info and the call cache.
This saves about 2 MiB on Discourse.

This change improves the Optcarrot benchmark at least 3%. For more
details, see attached bugs.ruby-lang.org ticket.

Complications:
 - A new instruction attribute `comptime_sp_inc` is introduced to
 calculate SP increase at compile time without using call caches. At
 compile time, a `TS_CALLDATA` operand points to a call info struct, but
 at runtime, the same operand points to a call data struct. Instruction
 that explicitly define `sp_inc` also need to define `comptime_sp_inc`.
 - MJIT code for copying call cache becomes slightly more complicated.
 - This changes the bytecode format, which might break existing tools.

[Misc #16258]

1 files changed, 1 insertions, 1 deletions

diff --git a/vm_insnhelper.h b/vm_insnhelper.h
index 9f09d4ab5e..99555fd4ed 100644
--- a/vm_insnhelper.h
+++ b/vm_insnhelper.h
@@ -166,7 +166,7 @@ enum vm_regan_acttype {
 #ifndef MJIT_HEADER
 #define CALL_SIMPLE_METHOD() do { \
     rb_snum_t x = leaf ? INSN_ATTR(width) : 0; \
-    rb_snum_t y = attr_width_opt_send_without_block(0, 0); \
+    rb_snum_t y = attr_width_opt_send_without_block(0); \
     rb_snum_t z = x - y; \
     ADD_PC(z); \
     DISPATCH_ORIGINAL_INSN(opt_send_without_block); \