[Tarantool-patches] [PATCH luajit 1/2] test: add utility for parsing `jit.dump`

[Maxim Kokryashkin]

Hi again!
It seems like I keep forgetting a single nit in every
review today.
 
I am concerned about the `test/tarantool-tests/utils/jit_parse.lua`
path, since we already have the `test/tarantool-tests/utils.lua`
module. I think we should rename this directory to `tools` or
something like that.
--
Best regards,
Maxim Kokryashkin
 
  
>Понедельник, 15 мая 2023, 14:12 +03:00 от Maxim Kokryashkin via Tarantool-patches <tarantool-patches at dev.tarantool.org>:
> 
>Hi, Sergey!
>Thanks for the patch!
>Please consider my comments below.
> 
>> 
>>>This commit adds simple parser for traces to be analyzed in the test.
>>Typo: s/adds/adds a/
>>>For now nothing too fancy at all -- just start `jit.dump` to temporary
>>Typo: s/temporary/a temporary/
>>>file and parse and remove this file when dump is stopped. The array
>>>with resulting traces is returned.
>>>
>>>For now, just find a single IR by pattern and return ref number and IR,
>>>if exists. More functionality may be added if it will be necessary for
>>Typo: s/if exists/if they exist/
>>Typo: s/it will be/it is/
>>>tests.
>>>---
>>> test/tarantool-tests/utils/jit_parse.lua | 156 +++++++++++++++++++++++
>>> 1 file changed, 156 insertions(+)
>>> create mode 100644 test/tarantool-tests/utils/jit_parse.lua
>>>
>>>diff --git a/test/tarantool-tests/utils/jit_parse.lua b/test/tarantool-tests/utils/jit_parse.lua
>>>new file mode 100644
>>>index 00000000..fe8e0e08
>>>--- /dev/null
>>>+++ b/test/tarantool-tests/utils/jit_parse.lua
>>>@@ -0,0 +1,156 @@
>>>+local jdump = require('jit.dump')
>>>+
>>>+local M = {}
>>>+
>>>+local trace_mt = {}
>>>+trace_mt.__index = trace_mt
>>>+
>>>+-- Find and return the first IR ref and value matched the pattern
>>>+-- for the trace.
>>>+trace_mt.has_ir = function(trace, ir_pattern)
>>>+ for i = 1, #trace.ir do
>>>+ local ir = trace.ir[i]
>>>+ if ir:match(ir_pattern) then
>>>+ return i, ir
>>>+ end
>>>+ end
>>>+end
>>>+
>>>+local function trace_new(n)
>>>+ return setmetatable({
>>>+ number = n,
>>>+ parent = nil,
>>>+ parent_exitno = nil,
>>>+ start_loc = nil,
>>>+ bc = {},
>>>+ ir = {},
>>>+ mcode = {},
>>>+ snaps = {},
>>>+ }, trace_mt)
>>>+end
>>>+
>>>+local function parse_bc(trace, line)
>>>+ trace.bc[#trace.bc + 1] = line
>>>+end
>>>+
>>>+local function parse_snap(trace, n_snap, line)
>>>+ assert(trace.snaps[n_snap] == nil)
>>>+ trace[n_snap] = {ref = #trace.ir + 1, slots = line:match('%[(.*)%]$'),}
>>>+end
>>>+
>>>+local function parse_ir(trace, line)
>>>+ local n_snap = line:match('SNAP%s+#(%d+)')
>>>+ if n_snap then
>>>+ parse_snap(trace, n_snap, line)
>>>+ return
>>>+ end
>>>+
>>>+ local current_ins, ir = line:match('^(%d+)%s+(.*)$')
>>>+ current_ins = tonumber(current_ins)
>>>+ -- Insert NOP instruction hidden in IR dump.
>>>+ if current_ins ~= #trace.ir + 1 then
>>>+ trace.ir[#trace.ir + 1] = 'nil NOP'
>>>+ end
>>>+ assert(current_ins == #trace.ir + 1)
>>>+ trace.ir[current_ins] = ir
>>>+end
>>>+
>>>+local function parse_mcode(trace, line)
>>>+ -- Skip loop label.
>>>+ if line == '-> LOOP:' then
>>>+ return
>>>+ end
>>>+ local addr, instruction = line:match('^(%w+)%s+(.*)$')
>>>+ trace.mcode[#trace.mcode + 1] = {addr = addr, instruction = instruction,}
>>>+end
>>>+
>>>+local function parse_trace_hdr(ctx, line, trace_num, status)
>>>+ local traces = ctx.traces
>>>+ if status == 'start' then
>>>+ local trace = trace_new(trace_num)
>>>+ trace.parent, trace.parent_exitno = line:match('start (%d+)/(%d+)')
>>>+ -- XXX: Assume, that source line can't contain spaces.
>>>+ -- For example, it's not "(command line)".
>>>+ trace.start_loc = line:match(' ([^%s]+)$')
>>>+ traces[trace_num] = trace
>>>+ ctx.parsing_trace = trace_num
>>>+ ctx.parsing = 'bc'
>>>+ elseif status == 'stop' then
>>>+ assert(ctx.parsing_trace == trace_num)
>>>+ ctx.parsing_trace = nil
>>>+ ctx.parsing = nil
>>>+ elseif status == 'abort' then
>>>+ assert(ctx.parsing_trace == trace_num)
>>>+ ctx.parsing_trace = nil
>>>+ ctx.parsing = nil
>>>+ traces[trace_num] = nil
>>Two branches below are almost identical. Is it possible to avoid
>>duplication?
>>Side note: Also, I like it much more when switch-like constructions
>>in Lua are implemented with tables, because it seems to be cleaner.
>>Feel free to ignore.
>>>+ elseif status == 'IR' then
>>>+ ctx.parsing = 'IR'
>>>+ elseif status == 'mcode' then
>>>+ ctx.parsing = 'mcode'
>>>+ else
>>>+ error('Unknown trace status: ' .. status)
>>>+ end
>>>+end
>>>+
>>>+local function parse_line(ctx, line)
>>>+ if line == '' then
>>>+ return
>>>+ end
>>>+
>>>+ if line:match('TRACE flush') then
>>>+ ctx.traces = {}
>>>+ return
>>>+ end
>>>+
>>>+ local trace_num, status = line:match('TRACE (%d+) (%w+)')
>>>+ if trace_num then
>>>+ parse_trace_hdr(ctx, line, tonumber(trace_num), status)
>>>+ return
>>>+ end
>>>+
>>>+ assert(ctx.parsing_trace)
>>>+
>>>+ local trace = ctx.traces[ctx.parsing_trace]
>>>+ if ctx.parsing == 'bc' then
>>>+ parse_bc(trace, line)
>>>+ elseif ctx.parsing == 'IR' then
>>>+ parse_ir(trace, line)
>>>+ elseif ctx.parsing == 'mcode' then
>>>+ parse_mcode(trace, line)
>>>+ end
>>>+end
>>>+
>>>+local JDUMP_FILE
>>>+
>>>+local function parse_jit_dump()
>>>+ local ctx = {traces = {}}
>>>+ for line in io.lines(JDUMP_FILE) do
>>I think we should perform error checking for that io operation.
>>>+ parse_line(ctx, line)
>>>+ end
>>>+ return ctx.traces
>>>+end
>>>+
>>>+M.start = function(flags)
>>>+ assert(JDUMP_FILE == nil, 'jit_parse is already running')
>>>+ -- Always use plain text output.
>>>+ flags = flags .. 'T'
>>Nit: What if either `A` or `H` is present in the flags? I believe, no
>>one is going to do such things, but anyway it is worth considering
>>as a thing to check. Feel free to ignore.
>>>+ JDUMP_FILE = os.tmpname()
>>>+ jdump.start(flags, JDUMP_FILE)
>>>+end
>>>+
>>>+M.finish = function()
>>>+ assert(JDUMP_FILE ~= nil, 'jit_parse is not running')
>>>+ jdump.off()
>>>+ local traces = parse_jit_dump()
>>>+ os.remove(JDUMP_FILE)
>>>+ JDUMP_FILE = nil
>>>+ return traces
>>>+end
>>>+
>>>+-- Turn off compilation for these modules to avoid side effects.
>>>+jit.off(true, true)
>>>+jit.off(jdump.on, true)
>>>+jit.off(jdump.off, true)
>>>+
>>>+return M
>>>--
>>>2.34.1
>>--
>>Best regards,
>>Maxim Kokryashkin
>> 
 
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