the lua code:
require("jit.v").on("re_jit1.log")
for i = 1, max do
local function f(v)
return v + i
end
f(10)
end
the log of jit.v:
[TRACE --- t1.lua:4 -- NYI: bytecode 51 at t1.lua:7]
[TRACE --- t1.lua:4 -- NYI: bytecode 51 at t1.lua:7]
Create closure NYI, so i change the code:
require("jit.v").on("t1.log")
local wrapper = {}
setmetatable(wrapper, { __call = function(self, v)
print(self.i)
return v * self.i
end})
local max = 100
for i = 1, max do
wrapper.i = i
wrapper(10)
end
the corresponding log:
[TRACE 1 t1.lua:8 loop]
the effect is excellent. but in this code:
require("jit.v").on("tailcall_jit1.log")
local function f1(val)
if val <= 0 then
return
end
f1(val - 1)
end
for i = 1, 100 do
xpcall(f1, debug.traceback, i)
end
i have new problem:
[TRACE 1 tailcall_jit1.lua:3 up-recursion]
[TRACE --- (1/3) tailcall_jit1.lua:5 -- down-recursion, restarting at tailcall_jit1.lua:9]
[TRACE 2 tailcall_jit1.lua:9 down-recursion]
[TRACE 3 (1/1) tailcall_jit1.lua:5 -> 2]
[TRACE 4 (1/3) tailcall_jit1.lua:5 -> 2]
[TRACE 5 (1/4) tailcall_jit1.lua:5 -> 2]
[TRACE 6 tailcall_jit1.lua:11 -> 1]
[TRACE --- (2/3) tailcall_jit1.lua:9 -- NYI: return to lower frame]
[TRACE --- (2/1) tailcall_jit1.lua:9 -- NYI: return to lower frame]
[TRACE --- (2/1) tailcall_jit1.lua:9 -- NYI: return to lower frame]
[TRACE --- (2/1) tailcall_jit1.lua:9 -- NYI: return to lower frame]
[TRACE --- (2/1) tailcall_jit1.lua:9 -- NYI: return to lower frame]
[TRACE 7 (2/1) tailcall_jit1.lua:9 -- fallback to interpreter]
[TRACE --- (2/2) tailcall_jit1.lua:9 -- NYI: return to lower frame]
[TRACE --- (2/3) tailcall_jit1.lua:9 -- NYI: return to lower frame]
[TRACE --- (2/2) tailcall_jit1.lua:9 -- NYI: return to lower frame]
[TRACE --- (2/3) tailcall_jit1.lua:9 -- NYI: return to lower frame]
[TRACE --- (2/2) tailcall_jit1.lua:9 -- NYI: return to lower frame]
[TRACE --- (2/3) tailcall_jit1.lua:9 -- NYI: return to lower frame]
[TRACE --- (2/2) tailcall_jit1.lua:9 -- NYI: return to lower frame]
[TRACE 8 (2/3) tailcall_jit1.lua:9 -- fallback to interpreter]
[TRACE 9 (2/2) tailcall_jit1.lua:9 -- fallback to interpreter]
about NYI: return to lower frame, i search the wiki, it's said:
Tailcall. Some tailcalls to frames lower than the starting frame of the trace are not compiled.
or
Return from function. Returns to C frames and some returns to frames lower than the starting frame of the trace are not compiled.
So i dump the BC, and i found it's RET*, so i attempt to remove xpcall(), and the NYI was gone, then i found a commit, it said:
Don't try to record outermost pcall() return to lower frame.
i think i found the key, but i still confusion about this behavior, and if i have to use pcall/xpcall, how can i avoid this NYI?
