Bug 1820802 - Add a stress test for management of wasm-gc out-of-line storage blocks. r=rhunt.

// |jit-test| skip-if: !wasmGcEnabled() || getBuildConfiguration().simulator

// This test is intended to test what was committed in

//

//  Bug 1817385 - wasm-gc: reduce cost of allocation and GC paths

//  and

//  Bug 1820120 - Manage Wasm{Array,Struct}Object OOL-storage-blocks

//                using a thread-private cache

//

// and in particular the latter.  The patches in these bugs reduce the cost of

// wasm-gc struct/array allocation and collection, in part by better

// integrating those objects with our generational GC facility.

//

// Existing tests do not cover all of those paths.  In particular they do not

// exercise both set-subtraction algorithms in Nursery::freeTrailerBlocks.

// This test does, though.

//

// The test first creates an "primary" array of 1500 elements.  Each element

// is a reference to a secondary array of between 1 and 50 int32s.  These

// secondary arrays have size chosen randomly, and the elements are also

// random.

//

// Then, elements of the primary array are replaced.  An index in the range 0

// .. N - 1 is randomly chosen, and the element there is replaced by a

// randomly-created secondary array.  This is repeated 500,000 times with

// N = 800.

//

// Finally, all of the above is repeated, but with N = 1200.

//

// As a result just over a million arrays and their trailer blocks, of various

// sizes, are allocated and deallocated.  With N = 800, in

// js::Nursery::freeTrailerBlocks, we end up with trailersRemovedUsed_ of

// around 800, so one of the set-subtraction algorithms is exercised.

// With N = 1200, the other is exercised.  It's not entirely clear why changing

// N causes trailersRemovedUsed_ to have more or less the same value during

// nursery collection, but the correlation does seem fairly robust.

//

// The test is skipped on the simulator because it takes too long to run, and

// triggers timeouts.

let t =

`(module

   ;; A simple pseudo-random number generator.

   ;; Produces numbers in the range 0 .. 2^16-1.

   (global $rngState

     (mut i32) (i32.const 1)

   )

   (func $rand (export "rand") (result i32)

     (local $t i32)

     ;; update $rngState

     (local.set $t (global.get $rngState))

     (local.set $t (i32.mul (local.get $t) (i32.const 1103515245)))

     (local.set $t (i32.add (local.get $t) (i32.const 12345)))

     (global.set $rngState (local.get $t))

     ;; pull 16 random bits out of it

     (local.set $t (i32.shr_u (local.get $t) (i32.const 15)))

     (local.set $t (i32.and (local.get $t) (i32.const 0xFFFF)))

     (local.get $t)

   )

   ;; Array types

   (type $tArrayI32      (array (mut i32)))  ;; "secondary array" above

   (type $tArrayArrayI32 (array (mut (ref null $tArrayI32)))) ;; "primary array"

   ;; Create an array ("secondary array") containing random numbers, with a

   ;; size between 1 and 50, also randomly chosen.

   (func $createSecondaryArray (export "createSecondaryArray")

                               (result (ref $tArrayI32))

     (local $i i32)

     (local $nElems i32)

     (local $arr (ref $tArrayI32))

     (local.set $nElems (call $rand))

     (local.set $nElems (i32.rem_u (local.get $nElems) (i32.const 50)))

     (local.set $nElems (i32.add   (local.get $nElems) (i32.const 1)))

     (local.set $arr (array.new $tArrayI32 (i32.const 0) (local.get $nElems)))

     (loop $cont

       (array.set $tArrayI32 (local.get $arr) (local.get $i) (call $rand))

       (local.set $i (i32.add (local.get $i) (i32.const 1)))

       (br_if $cont (i32.lt_u (local.get $i) (local.get $nElems)))

     )

     (local.get $arr)

   )

   ;; Create an array (the "primary array") of 1500 elements of

   ;; type ref-of-tArrayI32.

   (func $createPrimaryArray (export "createPrimaryArray")

                             (result (ref $tArrayArrayI32))

     (local $i i32)

     (local $arrarr (ref $tArrayArrayI32))

     (local.set $arrarr (array.new $tArrayArrayI32 (ref.null $tArrayI32)

                                                   (i32.const 1500)))

     (loop $cont

       (array.set $tArrayArrayI32 (local.get $arrarr)

                                  (local.get $i) (call $createSecondaryArray))

       (local.set $i (i32.add (local.get $i) (i32.const 1)))

       (br_if $cont (i32.lt_u (local.get $i) (i32.const 1500)))

     )

     (local.get $arrarr)

   )

   ;; Use $createPrimaryArray to create an initial array.  Then randomly replace

   ;; elements for a while.

   (func $churn (export "churn") (param $thresh i32) (result i32)

     (local $i i32)

     (local $j i32)

     (local $finalSum i32)

     (local $arrarr (ref $tArrayArrayI32))

     (local $arr (ref null $tArrayI32))

     (local $arrLen i32)

     (local.set $arrarr (call $createPrimaryArray))

     ;; This loop iterates 500,000 times.  Each iteration, it chooses

     ;; a randomly element in $arrarr and replaces it with a new

     ;; random array of 32-bit ints.

     (loop $cont

       ;; make $j be a random number in 0 .. $thresh-1.

       ;; Then replace that index in $arrarr with a new random arrayI32.

       (local.set $j (i32.rem_u (call $rand) (local.get $thresh)))

       (array.set $tArrayArrayI32 (local.get $arrarr)

                                  (local.get $j) (call $createSecondaryArray))

       (local.set $i (i32.add (local.get $i) (i32.const 1)))

       (br_if $cont (i32.lt_u (local.get $i) (i32.const 500000)))

     )

     ;; Finally, compute a checksum by summing all the numbers

     ;; in all secondary arrays.  This simply assumes that all of the refs to

     ;; secondary arrays are non-null, which isn't per-se guaranteed by the

     ;; previous loop, but it works in this case because the RNG

     ;; produces each index value to overwrite at least once.

     (local.set $finalSum (i32.const 0))

     (local.set $i (i32.const 0)) ;; loop var for the outer loop

     (loop $outer

       ;; body of outer loop

       ;; $arr = $arrarr[i]

       (local.set $arr (array.get $tArrayArrayI32 (local.get $arrarr)

                       (local.get $i)))

       ;; iterate over $arr

       (local.set $arrLen (array.len (local.get $arr)))

       (local.set $j (i32.const 0)) ;; loop var for the inner loop

       (loop $inner

         ;; body of inner loop

         (local.set $finalSum

                    (i32.rotl (local.get $finalSum) (i32.const 1)))

         (local.set $finalSum

                    (i32.xor (local.get $finalSum)

                             (array.get $tArrayI32 (local.get $arr)

                                                   (local.get $j))))

         ;; loop control for the inner loop

         (local.set $j (i32.add (local.get $j) (i32.const 1)))

         (br_if $inner (i32.lt_u (local.get $j) (local.get $arrLen)))

       )

       ;; loop control for the outer loop

       (local.set $i (i32.add (local.get $i) (i32.const 1)))

       (br_if $outer (i32.lt_u (local.get $i) (i32.const 1500)))

     )

     ;; finally, roll in the final value of the RNG state

     (i32.xor (local.get $finalSum) (global.get $rngState))

   )

)`;

let i = wasmEvalText(t);

let fns = i.exports;

assertEq(fns.churn(800), -575895114);

assertEq(fns.churn(1200), -1164697516);