On 2015/06/25 18:58:32, arv wrote:
On 2015/06/25 18:48:19, paul.l... wrote:
> The stack layout is mixed up somewhere. I've not got a real fix, but
this
diff
> gets it a little farther:
>
> diff --git a/src/mips/builtins-mips.cc b/src/mips/builtins-mips.cc
> index e7ba9f1..adc4fb5 100644
> --- a/src/mips/builtins-mips.cc
> +++ b/src/mips/builtins-mips.cc
> @@ -646,6 +646,8 @@ static void
Generate_JSConstructStubHelper(MacroAssembler*
> masm,
> __ bind(&count_incremented);
> }
>
> + __ Pop(a1);
> +
> // Retrieve smi-tagged arguments count from the stack.
> __ lw(a0, MemOperand(sp, 0));
> __ SmiUntag(a0);
> @@ -654,7 +656,6 @@ static void
Generate_JSConstructStubHelper(MacroAssembler*
> masm,
> if (use_new_target) {
> __ Pop(a3); // new.target
> }
> - __ Pop(a1);
>
> if (use_new_target) {
> __ Push(a3, t4, t4);
>
> a0 was getting a tagged pointer, rather than the smi argument count you
wanted.
>
> I have to leave now for an appointment, I will be back in ~1.5 hours,
and
can
> look more.
>
> If you want to look further, build mipsel.debug with snapshot=off, then
start
up
> the shell with --trace-sim flag. You can see where it fails, and watch
the
> loads/stores to the stack.
>
> With the above patch it now fails where it is trying to offset the
stack by
some
> integer value, and is again loading a tagged pointer from stack into a1,
rather
> than an Smi.
>
> 0x26727d14 8fa20000 lw v0, 0(sp) 00000002
<--
> [f53cae60] (65888)
> 0x26727d18 8fa50004 lw a1, 4(sp) 26727941
<--
> [f53cae64] (65889) <<--- this gets left-shifted an added to sp,
as if
it
> was smi.
Thanks. Very useful. Hopefully I'll have it working by the time you come
back.
I fixed the push/pop discrepancy and now both mips and mips64 error out with
"Unaligned write".
https://codereview.chromium.org/1203813002/
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