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Re: Incorrect code due to indirect tail call of varargs function with hard float ABI
- From: Ramana Radhakrishnan <ramana dot radhakrishnan at foss dot arm dot com>
- To: Kugan <kugan dot vivekanandarajah at linaro dot org>, Ramana Radhakrishnan <ramana dot radhakrishnan at foss dot arm dot com>, Charles Baylis <charles dot baylis at linaro dot org>
- Cc: "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>, Richard Earnshaw <Richard dot Earnshaw at arm dot com>, Kyrill Tkachov <kyrylo dot tkachov at arm dot com>
- Date: Wed, 18 Nov 2015 09:19:51 +0000
- Subject: Re: Incorrect code due to indirect tail call of varargs function with hard float ABI
- Authentication-results: sourceware.org; auth=none
- References: <564A57BA dot 7050504 at linaro dot org> <CADnVucBHnigJL_kaG8rqUPeQLhF==_cm+tQCOMaAWH5UHWxpHQ at mail dot gmail dot com> <564A9327 dot 8070607 at linaro dot org> <564AFBEE dot 9050801 at foss dot arm dot com> <564B8655 dot 1060509 at linaro dot org> <564BC70C dot 70805 at linaro dot org>
On 18/11/15 00:32, Kugan wrote:
>> > Hi Ramana,
>> >
>> > Thanks for the review. I have opened a gcc bug-report for this. I tested
>> > the attached patch for arm-none-linux-gnueabihf and
>> > arm-none-linux-gnueabi with no new regressions. Is this OK?
>> >
>> >
>> > Thanks,
>> > Kugan
>> >
>> > gcc/ChangeLog:
>> >
>> > 2015-11-18 Kugan Vivekanandarajah <kuganv@linaro.org>
>> >
>> > PR target/68390
>> > * config/arm/arm.c (arm_function_ok_for_sibcall): Get function type
>> > for indirect function call.
>> >
>> > gcc/testsuite/ChangeLog:
>> >
>> > 2015-11-18 Kugan Vivekanandarajah <kuganv@linaro.org>
>> >
>> > PR target/68390
>> > * gcc.target/arm/PR68390.c: New test.
>> >
>> >
> Hi Ramana,
>
> With further testing on bare-metal, I found that for the following decl
> has to be null for indirect functions.
>
> if (TARGET_AAPCS_BASED
> && arm_abi == ARM_ABI_AAPCS
> && decl
> && DECL_WEAK (decl))
> return false;
Ok .. yes that's right.
>
> Here is the updated patch and ChangeLog. Sorry for the noise.
>
> Thanks,
> Kugan
>
>
> gcc/ChangeLog:
>
> 2015-11-18 Kugan Vivekanandarajah <kuganv@linaro.org>
>
> PR target/68390
> * config/arm/arm.c (arm_function_ok_for_sibcall): Get function type
> for indirect function call.
>
> gcc/testsuite/ChangeLog:
>
> 2015-11-18 Kugan Vivekanandarajah <kuganv@linaro.org>
>
> PR target/68390
> * gcc.target/arm/PR68390.c: New test.
>
s/PR/pr in the test name and put this in gcc.c-torture/execute instead - there is nothing ARM specific about the test. Tests in gcc.target/arm should really only be architecture specific. This isn't.
>
>
>
> p.txt
>
>
> diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
> index a379121..0dae7da 100644
> --- a/gcc/config/arm/arm.c
> +++ b/gcc/config/arm/arm.c
> @@ -6680,8 +6680,13 @@ arm_function_ok_for_sibcall (tree decl, tree exp)
> a VFP register but then need to transfer it to a core
> register. */
> rtx a, b;
> + tree fn_decl = decl;
Call it decl_or_type instead - it's really that ...
>
> - a = arm_function_value (TREE_TYPE (exp), decl, false);
> + /* If it is an indirect function pointer, get the function type. */
> + if (!decl)
> + fn_decl = TREE_TYPE (TREE_TYPE (CALL_EXPR_FN (exp)));
> +
This is probably just my mail client - but please watch out for indentation.
> + a = arm_function_value (TREE_TYPE (exp), fn_decl, false);
> b = arm_function_value (TREE_TYPE (DECL_RESULT (cfun->decl)),
> cfun->decl, false);
> if (!rtx_equal_p (a, b))
OK with those changes.
Ramana