Re: [Tarantool-patches] [PATCH luajit v1 3/5] test: allow `jit.parse` to return aborted traces

[Sergey Bronnikov via Tarantool-patches <tarantool-patches@dev.tarantool.org>]

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Sergey,


thanks for the patch! Please see my comments below.

On 22.04.2024 11:49, Sergey Kaplun wrote:
> Now information about the abort of the trace is saved in the
> `abort_reason` field of the corresponding structure. The
> `jit.parse.finish()` returns now the second table containing aborted
> traces. Each table key is a trace number containing an array of
> potentially traces with this number, which was aborted.
>
> Needed for tarantool/tarantool#9924
> ---
>   .../unit-jit-parse-abort.test.lua             | 38 +++++++++++++++++++
>   test/tarantool-tests/utils/jit/parse.lua      | 22 ++++++++---
>   2 files changed, 55 insertions(+), 5 deletions(-)
>   create mode 100644 test/tarantool-tests/unit-jit-parse-abort.test.lua
>
> diff --git a/test/tarantool-tests/unit-jit-parse-abort.test.lua b/test/tarantool-tests/unit-jit-parse-abort.test.lua
> new file mode 100644
> index 00000000..91af5a56
> --- /dev/null
> +++ b/test/tarantool-tests/unit-jit-parse-abort.test.lua
> @@ -0,0 +1,38 @@
> +local tap = require('tap')
> +local test = tap.test('unit-jit-parse'):skipcond({

Usually a name passed to `tap.test` matches to test file name,

but here it is not matched.

> +  ['Test requires JIT enabled'] = not jit.status(),
> +  ['Disabled on *BSD due to #4819'] = jit.os == 'BSD',
> +})
> +
> +local jparse = require('utils').jit.parse
> +
> +-- XXX: Avoid other traces compilation due to hotcount collisions
> +-- for predictable results.
> +jit.off()
> +jit.flush()
> +
> +test:plan(1)
> +
> +jit.on()
> +-- We only need the abort reason in the test.
> +jparse.start('t')

I would add a comment with explanation what does 't' flag mean.

Feel free to ignore.

> +
> +-- XXX: A trace always has at least 3 IR constants: for `nil`,
> +-- `false`, and `true`. Always fails to record with the set
> +-- `maxirconst` limit.
> +jit.opt.start('hotloop=1', 'maxirconst=1')
> +
> +for _ = 1, 3 do end
> +
> +local _, aborted_traces = jparse.finish()
> +
> +jit.off()
> +
> +assert(aborted_traces and aborted_traces[1], 'aborted trace is persisted')
> +
> +-- We tried to compile only one trace.
> +local reason = aborted_traces[1][1].abort_reason
> +
> +test:like(reason, 'trace too long', 'abort reason is correct')
> +
> +test:done(true)
> diff --git a/test/tarantool-tests/utils/jit/parse.lua b/test/tarantool-tests/utils/jit/parse.lua
> index bcef5b35..0ce7f7c8 100644
> --- a/test/tarantool-tests/utils/jit/parse.lua
> +++ b/test/tarantool-tests/utils/jit/parse.lua
> @@ -22,6 +22,7 @@ local function trace_new(n)
>       parent = nil,
>       parent_exitno = nil,
>       is_stitched = false,
> +    abort_reason = nil,
>       start_loc = nil,
>       bc = {},
>       ir = {},
> @@ -87,9 +88,17 @@ local header_handlers = {
>       ctx.parsing_trace = nil
>       ctx.parsing = nil
>     end,
> -  abort = function(ctx, trace_num)
> +  abort = function(ctx, trace_num, line)
>       local traces = ctx.traces
>       assert(ctx.parsing_trace == trace_num)
> +
> +    local aborted_traces = ctx.aborted_traces
> +    if not aborted_traces[trace_num] then
> +      aborted_traces[trace_num] = {}
> +    end
> +    traces[trace_num].abort_reason = line:match('-- (.+)$')
> +    table.insert(aborted_traces[trace_num], traces[trace_num])
> +
>       ctx.parsing_trace = nil
>       ctx.parsing = nil
>       traces[trace_num] = nil
> @@ -137,11 +146,14 @@ end
>   local JDUMP_FILE
>   
>   local function parse_jit_dump()
> -  local ctx = {traces = {}}
> +  local ctx = {
> +    aborted_traces = {},
> +    traces = {},
> +  }
>     for line in io.lines(JDUMP_FILE) do
>       parse_line(ctx, line)
>     end
> -  return ctx.traces
> +  return ctx.traces, ctx.aborted_traces
>   end
>   
>   -- Start `jit.dump()` utility with the given flags, saving the
> @@ -167,10 +179,10 @@ M.finish = function()
>     -- Enable traces compilation for `jit.dump` back.
>     jit.on(jdump.on, true)
>     jit.on(jdump.off, true)
> -  local traces = parse_jit_dump()
> +  local traces, aborted_traces = parse_jit_dump()
>     os.remove(JDUMP_FILE)
>     JDUMP_FILE = nil
> -  return traces
> +  return traces, aborted_traces
>   end
>   
>   -- Turn off compilation for the module to avoid side effects.

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