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// - when compiled with Ion, pass the TLS register to memory.size;
// - when compiled with Baseline, don't clobber the last stack slot when
// calling into memory.size/memory.grow;
// This toy module starts with an empty memory, then tries to set values at different
// indexes, automatically growing memory when that would trigger an out of
// bounds access, for the exact right amount of pages. Note it's not made for
// efficiency, but optimizing it doesn't trigger the bugs mentioned above.
let i = new WebAssembly.Instance(new WebAssembly.Module(wasmTextToBinary(`
(module
(memory $mem (export "mem") 0 65535)
(func (export "cur_mem") (result i32) (memory.size))
(func $maybeGrow (param $i i32) (local $smem i32)
;; get memory.size in number of bytes, not pages.
memory.size
i64.extend_i32_u
i64.const 65536
i64.mul
;; get the last byte index accessed by an int32 access.
local.get $i
i32.const 3
i32.add
local.tee $i
i64.extend_i32_u
;; if the memory is too small, grow it.
i64.le_u
if
;; get the floor of the accessed *page* index.
local.get $i
i64.extend_i32_u
i64.const 65536
i64.div_u
;; subtract to that the size of the current memory in pages;
;; that's the amount of pages we want to grow, minus one.
memory.size
i64.extend_i32_u
i64.sub
;; add 1 to that amount.
i64.const 1
i64.add
;; get back to i32 and grow memory.
i32.wrap_i64
memory.grow
drop
end
)
(func (export "set") (param $i i32) (param $v i32)
local.get $i
call $maybeGrow
local.get $i
local.get $v
i32.store
)
(func (export "get") (param $i i32) (result i32)
local.get $i
i32.load
)
)
`))).exports;
assertEq(i.cur_mem(), 0);
i.set(0, 1);
assertEq(i.get(0), 1);
assertEq(i.cur_mem(), 1);
i.set(1234, 1);
assertEq(i.get(1234), 1);
assertEq(i.cur_mem(), 1);
i.set(65532, 1);
assertEq(i.get(65532), 1);
assertErrorMessage(() => i.get(65533), WebAssembly.RuntimeError, /index out of bounds/);
assertEq(i.cur_mem(), 1);
i.set(65533, 1);
assertEq(i.get(65533), 1);
assertEq(i.cur_mem(), 2);