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

[Maxim Kokryashkin via Tarantool-patches <tarantool-patches@dev.tarantool.org>]

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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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