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From: "Alex Bennée" <alex.bennee@linaro.org>
To: Shu-Chun Weng <scw@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
	Richard Henderson <richard.henderson@linaro.org>,
	qemu-devel@nongnu.org
Subject: Re: [PATCH] Makes softmmu compile with clang at HEAD
Date: Mon, 30 Mar 2020 22:55:16 +0100	[thread overview]
Message-ID: <87r1x9fqyj.fsf@linaro.org> (raw)
In-Reply-To: <20200318062057.224953-1-scw@google.com>


Shu-Chun Weng <scw@google.com> writes:

> With clang at HEAD, linking fails with "undefined symbol:
> qemu_build_not_reached". It's because `store_helper` and
> `helper_ret_stb_mmu` are mutually recursive and clang inlined latter
> inside the former, making `store_helper` a recursive function and no
> longer fully inlineable preventing constant propogation.
>
> Signed-off-by: Shu-Chun Weng <scw@google.com>
> ---
>  accel/tcg/cputlb.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c
> index e3b5750c3b..a7c812ed72 100644
> --- a/accel/tcg/cputlb.c
> +++ b/accel/tcg/cputlb.c
> @@ -2050,6 +2050,7 @@ store_helper(CPUArchState *env, target_ulong addr, uint64_t val,
>      store_memop(haddr, val, op);
>  }
>  
> +__attribute__((noinline))
>  void helper_ret_stb_mmu(CPUArchState *env, target_ulong addr, uint8_t val,
>                          TCGMemOpIdx oi, uintptr_t retaddr)

Hmm I wonder if the correct fix is for store_helper to callL

  store_memop(addr + i, val8, MO_UB);

direct in the fallback case - although the page crossing may be tricky
to get right. Perhaps we should out of line all the unaligned stuff?


-- 
Alex Bennée


      parent reply	other threads:[~2020-03-30 21:56 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-18  6:20 [PATCH] Makes softmmu compile with clang at HEAD Shu-Chun Weng
2020-03-30 20:58 ` Shu-Chun Weng
2020-03-30 21:55 ` Alex Bennée [this message]

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