[Tarantool-patches] [PATCH luajit 2/2] test: relax JIT setup in misc.getmetrics test

[Igor Munkin]

To test whether <jit_snap_restore> metric is counted right for side
exits <minstitch> JIT engine parameter is tighted to prevent side trace
compilation (considering <math.fmod> being used for the corresponding
branch of execution, the side trace will try to compile with stitching).
However, if test is run on the platform configured with the option
LUAJIT_ENABLE_CHECKHOOK enabled, the resulting trace exceeds the
hardcoded <minstitch> limit and the metric is miscounted due to this new
trace. To resolve this issue <minstitch> limit is set to the maximum
amount of IRRef in the trace, preventing trace compilation for any
LuaJIT configuration.

Relates to tarantool/tarantool#7762

Signed-off-by: Igor Munkin <imun at tarantool.org>
---
 test/tarantool-tests/misclib-getmetrics-capi.test.lua | 7 +++++--
 test/tarantool-tests/misclib-getmetrics-lapi.test.lua | 7 +++++--
 test/tarantool-tests/utils.lua                        | 9 +++++++++
 3 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/test/tarantool-tests/misclib-getmetrics-capi.test.lua b/test/tarantool-tests/misclib-getmetrics-capi.test.lua
index 0cbc6cae..42a9adf9 100644
--- a/test/tarantool-tests/misclib-getmetrics-capi.test.lua
+++ b/test/tarantool-tests/misclib-getmetrics-capi.test.lua
@@ -1,5 +1,7 @@
+local utils = require('utils')
+
 -- Disabled on *BSD due to #4819.
-require('utils').skipcond(jit.os == 'BSD', 'Disabled due to #4819')
+utils.skipcond(jit.os == 'BSD', 'Disabled due to #4819')
 
 local path = arg[0]:gsub('%.test%.lua', '')
 local suffix = package.cpath:match('?.(%a+);')
@@ -94,7 +96,8 @@ end))
 
 -- Compiled loop with a side exit which does not get compiled.
 test:ok(testgetmetrics.snap_restores(function()
-    jit.opt.start(0, "hotloop=1", "hotexit=2", "minstitch=15")
+    jit.opt.start(0, "hotloop=1", "hotexit=2",
+                  ("minstitch=%d"):format(utils.const.maxnins))
 
     local function foo(i)
         -- math.fmod is not yet compiled!
diff --git a/test/tarantool-tests/misclib-getmetrics-lapi.test.lua b/test/tarantool-tests/misclib-getmetrics-lapi.test.lua
index 222e7d01..19dfd199 100644
--- a/test/tarantool-tests/misclib-getmetrics-lapi.test.lua
+++ b/test/tarantool-tests/misclib-getmetrics-lapi.test.lua
@@ -2,8 +2,10 @@
 -- Major portions taken verbatim or adapted from the LuaVela testing suite.
 -- Copyright (C) 2015-2019 IPONWEB Ltd.
 
+local utils = require('utils')
+
 -- Disabled on *BSD due to #4819.
-require('utils').skipcond(jit.os == 'BSD', 'Disabled due to #4819')
+utils.skipcond(jit.os == 'BSD', 'Disabled due to #4819')
 
 local tap = require('tap')
 
@@ -279,7 +281,8 @@ test:test("snap-restores-loop-side-exit-non-compiled", function(subtest)
     -- Compiled loop with a side exit which does not get compiled.
     subtest:plan(1)
 
-    jit.opt.start(0, "hotloop=1", "hotexit=2", "minstitch=15")
+    jit.opt.start(0, "hotloop=1", "hotexit=2",
+                  ("minstitch=%d"):format(utils.const.maxnins))
 
     local function foo(i)
         -- math.fmod is not yet compiled!
diff --git a/test/tarantool-tests/utils.lua b/test/tarantool-tests/utils.lua
index 87f7ff15..eb11d40d 100644
--- a/test/tarantool-tests/utils.lua
+++ b/test/tarantool-tests/utils.lua
@@ -135,4 +135,13 @@ function M.profilename(name)
   return (arg[0]:gsub('^(.+)/([^/]+)%.test%.lua$', replacepattern))
 end
 
+M.const = {
+  -- XXX: Max nins is limited by max IRRef, that equals to
+  -- REF_DROP - REF_BIAS. Unfortunately, these constants are not
+  -- provided to Lua space, so we ought to make some math:
+  -- * REF_DROP = 0xffff
+  -- * REF_BIAS = 0x8000
+  maxnins = 0xffff - 0x8000,
+}
+
 return M
-- 
2.34.0