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author | ko1 <ko1@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2012-06-15 10:22:34 +0000 |
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committer | ko1 <ko1@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2012-06-15 10:22:34 +0000 |
commit | 745c23b2d981e23024f044e934967bc6dae66d80 (patch) | |
tree | 9fd909ad9129bf5b11bbe1cbf77a11b6d9fc37b8 /enc/gb18030.c | |
parent | 0dc5b8ce8c11d196ed44d333c4bfae8c7f2d0bac (diff) | |
download | ruby-745c23b2d981e23024f044e934967bc6dae66d80.tar.gz |
* vm_core.h: remove VM_FRAME_MAGIC_FINISH (finish frame type).
Before this commit:
`finish frame' was place holder which indicates that VM loop
needs to return function.
If a C method calls a Ruby methods (a method written by Ruby),
then VM loop will be (re-)invoked. When the Ruby method returns,
then also VM loop should be escaped. `finish frame' has only
one instruction `finish', which returns VM loop function.
VM loop function executes `finish' instruction, then VM loop
function returns itself.
With such mechanism, `leave' instruction (which returns one
frame from current scope) doesn't need to check that this `leave'
should also return from VM loop function.
Strictly, one branch can be removed from `leave' instructon.
Consideration:
However, pushing the `finish frame' needs costs because
it needs several memory accesses. The number of pushing
`finish frame' is greater than I had assumed. Of course,
pushing `finish frame' consumes additional control frame.
Moreover, recent processors has good branch prediction,
with which we can ignore such trivial checking.
After this commit:
Finally, I decide to remove `finish frame' and `finish'
instruction. Some parts of VM depend on `finish frame',
so the new frame flag VM_FRAME_FLAG_FINISH is introduced.
If this frame should escape from VM function loop, then
the result of VM_FRAME_TYPE_FINISH_P(cfp) is true.
`leave' instruction checks this flag every time.
I measured performance on it. However on my environments,
it improves some benchmarks and slows some benchmarks down.
Maybe it is because of C compiler optimization parameters.
I'll re-visit here if this cause problems.
* insns.def (leave, finish): remove finish instruction.
* vm.c, vm_eval.c, vm_exec.c, vm_backtrace.c, vm_dump.c:
apply above changes.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@36099 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Diffstat (limited to 'enc/gb18030.c')
0 files changed, 0 insertions, 0 deletions