[2pt] Enrich symtab when the new function's prototype is allocated

[veod32]

Product: Tarantool
Since: 2.10
Root document: https://www.tarantool.io/en/doc/latest/book/app_server/luajit_memprof/
Dev issue: tarantool/tarantool#5815
SME: @ igormunkin , @ Buristan

Details

If one runs this test chunk named <tests.lua>:

1  jit.off()
2
3  local ffi = require 'ffi'
4
5  local binfile = "/tmp/memprof_"..(arg[0]):match("([^/]*).lua")..".bin"
6
7  local st, err = misc.memprof.start(binfile)
8  assert(st, err)
9
10 local chunk = [[
11 local t = {
12   string.rep("x", 11111), 42, nil
13 }
14
15 function lua_global_f()
16   local str = string.rep("1", 1024 * 1024)
17 end
18 ]]
19
20 local f, err = loadstring(chunk)
21 assert(f, err)
22 f()
23 lua_global_f()
24
25 collectgarbage()
26
27 local st, err = misc.memprof.stop()
28 assert(st, err)

by Tarantool:

$ tarantool tests.lua

and runs the profiler parser, the output is the following:

$ tarantool -e 'require("memprof")(arg[1])' - /tmp/memprof_tests.bin
ALLOCATIONS
@tests.lua:0, line 20: 17	1736	0
@builtin/strict.lua:14, line 15: 3	458	0
CFUNC 0x401747a0: 1	1048593	0  --<-- lua_global_f()
CFUNC 0x41ea1e18: 1	11128	0  --<-- f()
CFUNC 0x41ea1e18: 1	20	0
CFUNC 0x41ea1e18: 1	72	0
...

This happens because the prototype of the lua_global_f() and f() functions does not exist when the profiler starts.
To report allocations from the new functions, the allocation events should be enriched with the info about new prototypes.

[mkokryashkin]

Now memprof's report looks like this:

ALLOCATIONS
@test.lua:17: 21 events	+1810 bytes	-0 bytes
function_alias_1:6: 1 events	+1048593 bytes	-0 bytes
function_alias_1:2: 1 events	+11128 bytes	-0 bytes
function_alias_1:1: 1 events	+72 bytes	-0 bytes
function_alias_1:7: 1 events	+20 bytes	-0 bytes

REALLOCATIONS
function_alias_1:2: 1 events	+16384 bytes	-32 bytes
INTERNAL: 1 events	+524288 bytes	-1048576 bytes
	Overrides:
		function_alias_1:6

function_alias_1:6: 1 events	+1048576 bytes	-16384 bytes
	Overrides:
		function_alias_1:2

@test.lua:17: 1 events	+128 bytes	-64 bytes
	Overrides:
		@test.lua:17


DEALLOCATIONS
INTERNAL: 27 events	+0 bytes	-1061728 bytes
	Overrides:
		@test.lua:17
		function_alias_1:1
		function_alias_1:2
		function_alias_1:6

@test.lua:17: 8 events	+0 bytes	-768 bytes
	Overrides:
		@test.lua:17


HEAP SUMMARY:
function_alias_1:2 holds 1032192 bytes: 2 allocs, 2 frees
@test.lua:17 holds 428 bytes: 22 allocs, 15 frees
function_alias_1:7 holds 20 bytes: 1 allocs, 0 frees

ALIASES:
function_alias_1:
1	| local t = {
2	|  string.rep("x", 11111), 42, nil
3	| }
4	| function lua_global_f()
5	|  local str = string.rep("1", 1024 * 1024)
6	| end