[PATCH] arm: Remove duplicate entries in isr_attribute_args [PR target/57002]

[PATCH] arm: Remove duplicate entries in isr_attribute_args [PR target/57002]

[Christophe Lyon]

Remove two duplicate entries in isr_attribute_args ("abort" and
"ABORT").

2020-04-29  Christophe Lyon  <christophe.lyon@linaro.org>

	PR target/57002
	gcc/
	* config/arm/arm.c (isr_attribute_args): Remove duplicate entries.
---
 gcc/config/arm/arm.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index 30a2a3a..6a6e804 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -3925,8 +3925,6 @@ static const isr_attribute_arg isr_attribute_args [] =
   { "fiq",   ARM_FT_FIQ },
   { "ABORT", ARM_FT_ISR },
   { "abort", ARM_FT_ISR },
-  { "ABORT", ARM_FT_ISR },
-  { "abort", ARM_FT_ISR },
   { "UNDEF", ARM_FT_EXCEPTION },
   { "undef", ARM_FT_EXCEPTION },
   { "SWI",   ARM_FT_EXCEPTION },
-- 
2.7.4

[PATCH] arm: Warn if IRQ handler is not compiled with -mgeneral-regs-only [PR target/94743]

[Christophe Lyon]

The interrupt attribute does not guarantee that the FP registers are
saved, which can result in problems difficult to debug.

Saving the FP registers and status registers can be a large penalty,
so it's probably not desirable to do that all the time.

If the handler calls other functions, we'd likely need to save all of
them, for lack of knowledge of which registers they actually use.

This is even more obscure for the end-user when the compiler inserts
calls to helper functions such as memcpy (some multilibs do use FP
registers to speed it up).

In the PR, we discussed adding routines in libgcc to save the FP
context and saving only locally-clobbered FP registers, but I think
this is too intrusive for stage 4.

In the mean time, emit a warning to suggest re-compiling with
-mgeneral-regs-only. Note that this can lead to errors if the code
uses floating-point and -mfloat-abi=hard, eg:
argument of type 'double' not permitted with -mgeneral-regs-only

This can be troublesome for the user, but at least this would make
them aware of the latent issue.

The patch adds two testcases:
- pr94734-1.c checks that a warning is emitted. One function can make
  implicit calls to runtime floating-point routines, the other one
  doesn't. We can improve the diagnostic later not to warn in the
  second case.

- pr94734-2.c checks that no warning is emitted when using
  -mgeneral-regs-only.

2020-04-29  Christophe Lyon  <christophe.lyon@linaro.org>

	PR target/94743
	gcc/
	* config/arm/arm.c (arm_handle_isr_attribute): Warn if
	-mgeneral-regs-only is not used.

	gcc/testsuite/
	* gcc.target/arm/pr94743-1.c: New test.
	* gcc.target/arm/pr94743-2.c: New test.
---
 gcc/config/arm/arm.c                     |  5 +++++
 gcc/testsuite/gcc.target/arm/pr94743-1.c | 20 ++++++++++++++++++++
 gcc/testsuite/gcc.target/arm/pr94743-2.c | 17 +++++++++++++++++
 3 files changed, 42 insertions(+)
 create mode 100644 gcc/testsuite/gcc.target/arm/pr94743-1.c
 create mode 100644 gcc/testsuite/gcc.target/arm/pr94743-2.c

diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index 6a6e804..34aad1d 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -7176,6 +7176,11 @@ arm_handle_isr_attribute (tree *node, tree name, tree args, int flags,
 		   name);
 	  *no_add_attrs = true;
 	}
+      else if (TARGET_VFP_BASE)
+	{
+	  warning (OPT_Wattributes, "FP registers might be clobbered despite %qE attribute: compile with -mgeneral-regs-only",
+		   name);
+	}
       /* FIXME: the argument if any is checked for type attributes;
 	 should it be checked for decl ones?  */
     }
diff --git a/gcc/testsuite/gcc.target/arm/pr94743-1.c b/gcc/testsuite/gcc.target/arm/pr94743-1.c
new file mode 100644
index 0000000..67700c6
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/pr94743-1.c
@@ -0,0 +1,20 @@
+/* PR target/94743 */
+/* { dg-do compile } */
+
+typedef struct {
+  double fpdata[32];
+} dummy_t;
+
+dummy_t global_d;
+dummy_t global_d1;
+
+__attribute__ ((interrupt("IRQ"))) void IRQ_HDLR_Test(void)
+{ /* { dg-warning { FP registers might be clobbered despite 'interrupt' attribute: compile with -mgeneral-regs-only} "" { target *-*-* } . } */
+  global_d.fpdata[3] += global_d.fpdata[3] * global_d1.fpdata[3];
+}
+
+
+__attribute__ ((interrupt("IRQ"))) void IRQ_HDLR_Test2(void)
+{ /* { dg-warning { FP registers might be clobbered despite 'interrupt' attribute: compile with -mgeneral-regs-only} "" { target *-*-* } . } */
+  global_d.fpdata[3] = 1.0;
+}
diff --git a/gcc/testsuite/gcc.target/arm/pr94743-2.c b/gcc/testsuite/gcc.target/arm/pr94743-2.c
new file mode 100644
index 0000000..745fd36
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/pr94743-2.c
@@ -0,0 +1,17 @@
+/* PR target/94743 */
+/* { dg-do compile } */
+/* { dg-options "-mgeneral-regs-only" } */
+
+typedef struct {
+  /* Do not use floating-point types, which are not be compatible with
+     -mgeneral-regs-only under -mfloat-abi=hard */
+  int fpdata[32];
+} dummy_t;
+
+dummy_t global_d;
+dummy_t global_d1;
+
+__attribute__ ((interrupt("IRQ"))) void IRQ_HDLR_Test(void)
+{
+  global_d.fpdata[3] += global_d.fpdata[3] * global_d1.fpdata[3];
+}
-- 
2.7.4

Re: [PATCH] arm: Remove duplicate entries in isr_attribute_args [PR target/57002]

[Ramana Radhakrishnan]

On Wed, Apr 29, 2020 at 4:19 PM Christophe Lyon via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> Remove two duplicate entries in isr_attribute_args ("abort" and
> "ABORT").
>
> 2020-04-29  Christophe Lyon  <christophe.lyon@linaro.org>
>
>         PR target/57002
>         gcc/
>         * config/arm/arm.c (isr_attribute_args): Remove duplicate entries.


OK, this would count as obvious.

Ramana
> ---
>  gcc/config/arm/arm.c | 2 --
>  1 file changed, 2 deletions(-)
>
> diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
> index 30a2a3a..6a6e804 100644
> --- a/gcc/config/arm/arm.c
> +++ b/gcc/config/arm/arm.c
> @@ -3925,8 +3925,6 @@ static const isr_attribute_arg isr_attribute_args [] =
>    { "fiq",   ARM_FT_FIQ },
>    { "ABORT", ARM_FT_ISR },
>    { "abort", ARM_FT_ISR },
> -  { "ABORT", ARM_FT_ISR },
> -  { "abort", ARM_FT_ISR },
>    { "UNDEF", ARM_FT_EXCEPTION },
>    { "undef", ARM_FT_EXCEPTION },
>    { "SWI",   ARM_FT_EXCEPTION },
> --
> 2.7.4
>

RE: [PATCH] arm: Warn if IRQ handler is not compiled with -mgeneral-regs-only [PR target/94743]

[Kyrylo Tkachov]

Hi Christophe,

Sorry for the delay.

> -----Original Message-----
> From: Gcc-patches <gcc-patches-bounces@gcc.gnu.org> On Behalf Of
> Christophe Lyon via Gcc-patches
> Sent: 29 April 2020 16:19
> To: gcc-patches@gcc.gnu.org
> Subject: [PATCH] arm: Warn if IRQ handler is not compiled with -mgeneral-
> regs-only [PR target/94743]
> 
> The interrupt attribute does not guarantee that the FP registers are
> saved, which can result in problems difficult to debug.
> 
> Saving the FP registers and status registers can be a large penalty,
> so it's probably not desirable to do that all the time.
> 
> If the handler calls other functions, we'd likely need to save all of
> them, for lack of knowledge of which registers they actually use.
> 
> This is even more obscure for the end-user when the compiler inserts
> calls to helper functions such as memcpy (some multilibs do use FP
> registers to speed it up).
> 
> In the PR, we discussed adding routines in libgcc to save the FP
> context and saving only locally-clobbered FP registers, but I think
> this is too intrusive for stage 4.
> 
> In the mean time, emit a warning to suggest re-compiling with
> -mgeneral-regs-only. Note that this can lead to errors if the code
> uses floating-point and -mfloat-abi=hard, eg:
> argument of type 'double' not permitted with -mgeneral-regs-only
> 
> This can be troublesome for the user, but at least this would make
> them aware of the latent issue.
> 
> The patch adds two testcases:
> - pr94734-1.c checks that a warning is emitted. One function can make
>   implicit calls to runtime floating-point routines, the other one
>   doesn't. We can improve the diagnostic later not to warn in the
>   second case.
> 
> - pr94734-2.c checks that no warning is emitted when using
>   -mgeneral-regs-only.
> 
> 2020-04-29  Christophe Lyon  <christophe.lyon@linaro.org>
> 
> 	PR target/94743
> 	gcc/
> 	* config/arm/arm.c (arm_handle_isr_attribute): Warn if
> 	-mgeneral-regs-only is not used.
> 
> 	gcc/testsuite/
> 	* gcc.target/arm/pr94743-1.c: New test.
> 	* gcc.target/arm/pr94743-2.c: New test.
> ---
>  gcc/config/arm/arm.c                     |  5 +++++
>  gcc/testsuite/gcc.target/arm/pr94743-1.c | 20 ++++++++++++++++++++
>  gcc/testsuite/gcc.target/arm/pr94743-2.c | 17 +++++++++++++++++
>  3 files changed, 42 insertions(+)
>  create mode 100644 gcc/testsuite/gcc.target/arm/pr94743-1.c
>  create mode 100644 gcc/testsuite/gcc.target/arm/pr94743-2.c
> 
> diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
> index 6a6e804..34aad1d 100644
> --- a/gcc/config/arm/arm.c
> +++ b/gcc/config/arm/arm.c
> @@ -7176,6 +7176,11 @@ arm_handle_isr_attribute (tree *node, tree name,
> tree args, int flags,
>  		   name);
>  	  *no_add_attrs = true;
>  	}
> +      else if (TARGET_VFP_BASE)
> +	{
> +	  warning (OPT_Wattributes, "FP registers might be clobbered
> despite %qE attribute: compile with -mgeneral-regs-only",
> +		   name);
> +	}

Let's use %< and %> to quote -mgeneral-regs-only properly.
Ok with that change.
Thanks,
Kyrill

>        /* FIXME: the argument if any is checked for type attributes;
>  	 should it be checked for decl ones?  */
>      }
> diff --git a/gcc/testsuite/gcc.target/arm/pr94743-1.c
> b/gcc/testsuite/gcc.target/arm/pr94743-1.c
> new file mode 100644
> index 0000000..67700c6
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/arm/pr94743-1.c
> @@ -0,0 +1,20 @@
> +/* PR target/94743 */
> +/* { dg-do compile } */
> +
> +typedef struct {
> +  double fpdata[32];
> +} dummy_t;
> +
> +dummy_t global_d;
> +dummy_t global_d1;
> +
> +__attribute__ ((interrupt("IRQ"))) void IRQ_HDLR_Test(void)
> +{ /* { dg-warning { FP registers might be clobbered despite 'interrupt'
> attribute: compile with -mgeneral-regs-only} "" { target *-*-* } . } */
> +  global_d.fpdata[3] += global_d.fpdata[3] * global_d1.fpdata[3];
> +}
> +
> +
> +__attribute__ ((interrupt("IRQ"))) void IRQ_HDLR_Test2(void)
> +{ /* { dg-warning { FP registers might be clobbered despite 'interrupt'
> attribute: compile with -mgeneral-regs-only} "" { target *-*-* } . } */
> +  global_d.fpdata[3] = 1.0;
> +}
> diff --git a/gcc/testsuite/gcc.target/arm/pr94743-2.c
> b/gcc/testsuite/gcc.target/arm/pr94743-2.c
> new file mode 100644
> index 0000000..745fd36
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/arm/pr94743-2.c
> @@ -0,0 +1,17 @@
> +/* PR target/94743 */
> +/* { dg-do compile } */
> +/* { dg-options "-mgeneral-regs-only" } */
> +
> +typedef struct {
> +  /* Do not use floating-point types, which are not be compatible with
> +     -mgeneral-regs-only under -mfloat-abi=hard */
> +  int fpdata[32];
> +} dummy_t;
> +
> +dummy_t global_d;
> +dummy_t global_d1;
> +
> +__attribute__ ((interrupt("IRQ"))) void IRQ_HDLR_Test(void)
> +{
> +  global_d.fpdata[3] += global_d.fpdata[3] * global_d1.fpdata[3];
> +}
> --
> 2.7.4

Re: [PATCH] arm: Warn if IRQ handler is not compiled with -mgeneral-regs-only [PR target/94743]

[Christophe Lyon]

On Tue, 30 Jun 2020 at 15:16, Kyrylo Tkachov <Kyrylo.Tkachov@arm.com> wrote:
>
> Hi Christophe,
>
> Sorry for the delay.
>
> > -----Original Message-----
> > From: Gcc-patches <gcc-patches-bounces@gcc.gnu.org> On Behalf Of
> > Christophe Lyon via Gcc-patches
> > Sent: 29 April 2020 16:19
> > To: gcc-patches@gcc.gnu.org
> > Subject: [PATCH] arm: Warn if IRQ handler is not compiled with -mgeneral-
> > regs-only [PR target/94743]
> >
> > The interrupt attribute does not guarantee that the FP registers are
> > saved, which can result in problems difficult to debug.
> >
> > Saving the FP registers and status registers can be a large penalty,
> > so it's probably not desirable to do that all the time.
> >
> > If the handler calls other functions, we'd likely need to save all of
> > them, for lack of knowledge of which registers they actually use.
> >
> > This is even more obscure for the end-user when the compiler inserts
> > calls to helper functions such as memcpy (some multilibs do use FP
> > registers to speed it up).
> >
> > In the PR, we discussed adding routines in libgcc to save the FP
> > context and saving only locally-clobbered FP registers, but I think
> > this is too intrusive for stage 4.
> >
> > In the mean time, emit a warning to suggest re-compiling with
> > -mgeneral-regs-only. Note that this can lead to errors if the code
> > uses floating-point and -mfloat-abi=hard, eg:
> > argument of type 'double' not permitted with -mgeneral-regs-only
> >
> > This can be troublesome for the user, but at least this would make
> > them aware of the latent issue.
> >
> > The patch adds two testcases:
> > - pr94734-1.c checks that a warning is emitted. One function can make
> >   implicit calls to runtime floating-point routines, the other one
> >   doesn't. We can improve the diagnostic later not to warn in the
> >   second case.
> >
> > - pr94734-2.c checks that no warning is emitted when using
> >   -mgeneral-regs-only.
> >
> > 2020-04-29  Christophe Lyon  <christophe.lyon@linaro.org>
> >
> >       PR target/94743
> >       gcc/
> >       * config/arm/arm.c (arm_handle_isr_attribute): Warn if
> >       -mgeneral-regs-only is not used.
> >
> >       gcc/testsuite/
> >       * gcc.target/arm/pr94743-1.c: New test.
> >       * gcc.target/arm/pr94743-2.c: New test.
> > ---
> >  gcc/config/arm/arm.c                     |  5 +++++
> >  gcc/testsuite/gcc.target/arm/pr94743-1.c | 20 ++++++++++++++++++++
> >  gcc/testsuite/gcc.target/arm/pr94743-2.c | 17 +++++++++++++++++
> >  3 files changed, 42 insertions(+)
> >  create mode 100644 gcc/testsuite/gcc.target/arm/pr94743-1.c
> >  create mode 100644 gcc/testsuite/gcc.target/arm/pr94743-2.c
> >
> > diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
> > index 6a6e804..34aad1d 100644
> > --- a/gcc/config/arm/arm.c
> > +++ b/gcc/config/arm/arm.c
> > @@ -7176,6 +7176,11 @@ arm_handle_isr_attribute (tree *node, tree name,
> > tree args, int flags,
> >                  name);
> >         *no_add_attrs = true;
> >       }
> > +      else if (TARGET_VFP_BASE)
> > +     {
> > +       warning (OPT_Wattributes, "FP registers might be clobbered
> > despite %qE attribute: compile with -mgeneral-regs-only",
> > +                name);
> > +     }
>
> Let's use %< and %> to quote -mgeneral-regs-only properly.
> Ok with that change.

Hi Kyrill,

Thanks for the review, however I have posted v2 here:
https://gcc.gnu.org/pipermail/gcc-patches/2020-May/545747.html
(you approved v1)

It includes a few more testcases and updates to existing ones.

Is v2 OK with the quotation marks fixed?

Thanks

Christophe

> Thanks,
> Kyrill
>
> >        /* FIXME: the argument if any is checked for type attributes;
> >        should it be checked for decl ones?  */
> >      }
> > diff --git a/gcc/testsuite/gcc.target/arm/pr94743-1.c
> > b/gcc/testsuite/gcc.target/arm/pr94743-1.c
> > new file mode 100644
> > index 0000000..67700c6
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.target/arm/pr94743-1.c
> > @@ -0,0 +1,20 @@
> > +/* PR target/94743 */
> > +/* { dg-do compile } */
> > +
> > +typedef struct {
> > +  double fpdata[32];
> > +} dummy_t;
> > +
> > +dummy_t global_d;
> > +dummy_t global_d1;
> > +
> > +__attribute__ ((interrupt("IRQ"))) void IRQ_HDLR_Test(void)
> > +{ /* { dg-warning { FP registers might be clobbered despite 'interrupt'
> > attribute: compile with -mgeneral-regs-only} "" { target *-*-* } . } */
> > +  global_d.fpdata[3] += global_d.fpdata[3] * global_d1.fpdata[3];
> > +}
> > +
> > +
> > +__attribute__ ((interrupt("IRQ"))) void IRQ_HDLR_Test2(void)
> > +{ /* { dg-warning { FP registers might be clobbered despite 'interrupt'
> > attribute: compile with -mgeneral-regs-only} "" { target *-*-* } . } */
> > +  global_d.fpdata[3] = 1.0;
> > +}
> > diff --git a/gcc/testsuite/gcc.target/arm/pr94743-2.c
> > b/gcc/testsuite/gcc.target/arm/pr94743-2.c
> > new file mode 100644
> > index 0000000..745fd36
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.target/arm/pr94743-2.c
> > @@ -0,0 +1,17 @@
> > +/* PR target/94743 */
> > +/* { dg-do compile } */
> > +/* { dg-options "-mgeneral-regs-only" } */
> > +
> > +typedef struct {
> > +  /* Do not use floating-point types, which are not be compatible with
> > +     -mgeneral-regs-only under -mfloat-abi=hard */
> > +  int fpdata[32];
> > +} dummy_t;
> > +
> > +dummy_t global_d;
> > +dummy_t global_d1;
> > +
> > +__attribute__ ((interrupt("IRQ"))) void IRQ_HDLR_Test(void)
> > +{
> > +  global_d.fpdata[3] += global_d.fpdata[3] * global_d1.fpdata[3];
> > +}
> > --
> > 2.7.4
>

RE: [PATCH] arm: Warn if IRQ handler is not compiled with -mgeneral-regs-only [PR target/94743]

[Kyrylo Tkachov]

> -----Original Message-----
> From: Christophe Lyon <christophe.lyon@linaro.org>
> Sent: 30 June 2020 14:32
> To: Kyrylo Tkachov <Kyrylo.Tkachov@arm.com>
> Cc: gcc-patches@gcc.gnu.org
> Subject: Re: [PATCH] arm: Warn if IRQ handler is not compiled with -
> mgeneral-regs-only [PR target/94743]
> 
> On Tue, 30 Jun 2020 at 15:16, Kyrylo Tkachov <Kyrylo.Tkachov@arm.com>
> wrote:
> >
> > Hi Christophe,
> >
> > Sorry for the delay.
> >
> > > -----Original Message-----
> > > From: Gcc-patches <gcc-patches-bounces@gcc.gnu.org> On Behalf Of
> > > Christophe Lyon via Gcc-patches
> > > Sent: 29 April 2020 16:19
> > > To: gcc-patches@gcc.gnu.org
> > > Subject: [PATCH] arm: Warn if IRQ handler is not compiled with -
> mgeneral-
> > > regs-only [PR target/94743]
> > >
> > > The interrupt attribute does not guarantee that the FP registers are
> > > saved, which can result in problems difficult to debug.
> > >
> > > Saving the FP registers and status registers can be a large penalty,
> > > so it's probably not desirable to do that all the time.
> > >
> > > If the handler calls other functions, we'd likely need to save all of
> > > them, for lack of knowledge of which registers they actually use.
> > >
> > > This is even more obscure for the end-user when the compiler inserts
> > > calls to helper functions such as memcpy (some multilibs do use FP
> > > registers to speed it up).
> > >
> > > In the PR, we discussed adding routines in libgcc to save the FP
> > > context and saving only locally-clobbered FP registers, but I think
> > > this is too intrusive for stage 4.
> > >
> > > In the mean time, emit a warning to suggest re-compiling with
> > > -mgeneral-regs-only. Note that this can lead to errors if the code
> > > uses floating-point and -mfloat-abi=hard, eg:
> > > argument of type 'double' not permitted with -mgeneral-regs-only
> > >
> > > This can be troublesome for the user, but at least this would make
> > > them aware of the latent issue.
> > >
> > > The patch adds two testcases:
> > > - pr94734-1.c checks that a warning is emitted. One function can make
> > >   implicit calls to runtime floating-point routines, the other one
> > >   doesn't. We can improve the diagnostic later not to warn in the
> > >   second case.
> > >
> > > - pr94734-2.c checks that no warning is emitted when using
> > >   -mgeneral-regs-only.
> > >
> > > 2020-04-29  Christophe Lyon  <christophe.lyon@linaro.org>
> > >
> > >       PR target/94743
> > >       gcc/
> > >       * config/arm/arm.c (arm_handle_isr_attribute): Warn if
> > >       -mgeneral-regs-only is not used.
> > >
> > >       gcc/testsuite/
> > >       * gcc.target/arm/pr94743-1.c: New test.
> > >       * gcc.target/arm/pr94743-2.c: New test.
> > > ---
> > >  gcc/config/arm/arm.c                     |  5 +++++
> > >  gcc/testsuite/gcc.target/arm/pr94743-1.c | 20 ++++++++++++++++++++
> > >  gcc/testsuite/gcc.target/arm/pr94743-2.c | 17 +++++++++++++++++
> > >  3 files changed, 42 insertions(+)
> > >  create mode 100644 gcc/testsuite/gcc.target/arm/pr94743-1.c
> > >  create mode 100644 gcc/testsuite/gcc.target/arm/pr94743-2.c
> > >
> > > diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
> > > index 6a6e804..34aad1d 100644
> > > --- a/gcc/config/arm/arm.c
> > > +++ b/gcc/config/arm/arm.c
> > > @@ -7176,6 +7176,11 @@ arm_handle_isr_attribute (tree *node, tree
> name,
> > > tree args, int flags,
> > >                  name);
> > >         *no_add_attrs = true;
> > >       }
> > > +      else if (TARGET_VFP_BASE)
> > > +     {
> > > +       warning (OPT_Wattributes, "FP registers might be clobbered
> > > despite %qE attribute: compile with -mgeneral-regs-only",
> > > +                name);
> > > +     }
> >
> > Let's use %< and %> to quote -mgeneral-regs-only properly.
> > Ok with that change.
> 
> Hi Kyrill,
> 
> Thanks for the review, however I have posted v2 here:
> https://gcc.gnu.org/pipermail/gcc-patches/2020-May/545747.html
> (you approved v1)
> 
> It includes a few more testcases and updates to existing ones.
> 
> Is v2 OK with the quotation marks fixed?
> 

Oops, sorry. Yes that looks ok too (with the quotation fixed).
Kyrill

> Thanks
> 
> Christophe
> 
> > Thanks,
> > Kyrill
> >
> > >        /* FIXME: the argument if any is checked for type attributes;
> > >        should it be checked for decl ones?  */
> > >      }
> > > diff --git a/gcc/testsuite/gcc.target/arm/pr94743-1.c
> > > b/gcc/testsuite/gcc.target/arm/pr94743-1.c
> > > new file mode 100644
> > > index 0000000..67700c6
> > > --- /dev/null
> > > +++ b/gcc/testsuite/gcc.target/arm/pr94743-1.c
> > > @@ -0,0 +1,20 @@
> > > +/* PR target/94743 */
> > > +/* { dg-do compile } */
> > > +
> > > +typedef struct {
> > > +  double fpdata[32];
> > > +} dummy_t;
> > > +
> > > +dummy_t global_d;
> > > +dummy_t global_d1;
> > > +
> > > +__attribute__ ((interrupt("IRQ"))) void IRQ_HDLR_Test(void)
> > > +{ /* { dg-warning { FP registers might be clobbered despite 'interrupt'
> > > attribute: compile with -mgeneral-regs-only} "" { target *-*-* } . } */
> > > +  global_d.fpdata[3] += global_d.fpdata[3] * global_d1.fpdata[3];
> > > +}
> > > +
> > > +
> > > +__attribute__ ((interrupt("IRQ"))) void IRQ_HDLR_Test2(void)
> > > +{ /* { dg-warning { FP registers might be clobbered despite 'interrupt'
> > > attribute: compile with -mgeneral-regs-only} "" { target *-*-* } . } */
> > > +  global_d.fpdata[3] = 1.0;
> > > +}
> > > diff --git a/gcc/testsuite/gcc.target/arm/pr94743-2.c
> > > b/gcc/testsuite/gcc.target/arm/pr94743-2.c
> > > new file mode 100644
> > > index 0000000..745fd36
> > > --- /dev/null
> > > +++ b/gcc/testsuite/gcc.target/arm/pr94743-2.c
> > > @@ -0,0 +1,17 @@
> > > +/* PR target/94743 */
> > > +/* { dg-do compile } */
> > > +/* { dg-options "-mgeneral-regs-only" } */
> > > +
> > > +typedef struct {
> > > +  /* Do not use floating-point types, which are not be compatible with
> > > +     -mgeneral-regs-only under -mfloat-abi=hard */
> > > +  int fpdata[32];
> > > +} dummy_t;
> > > +
> > > +dummy_t global_d;
> > > +dummy_t global_d1;
> > > +
> > > +__attribute__ ((interrupt("IRQ"))) void IRQ_HDLR_Test(void)
> > > +{
> > > +  global_d.fpdata[3] += global_d.fpdata[3] * global_d1.fpdata[3];
> > > +}
> > > --
> > > 2.7.4
> >

Re: [PATCH] arm: Warn if IRQ handler is not compiled with -mgeneral-regs-only [PR target/94743]

[Christophe Lyon]

On Tue, 30 Jun 2020 at 15:34, Kyrylo Tkachov <Kyrylo.Tkachov@arm.com> wrote:
>
>
>
> > -----Original Message-----
> > From: Christophe Lyon <christophe.lyon@linaro.org>
> > Sent: 30 June 2020 14:32
> > To: Kyrylo Tkachov <Kyrylo.Tkachov@arm.com>
> > Cc: gcc-patches@gcc.gnu.org
> > Subject: Re: [PATCH] arm: Warn if IRQ handler is not compiled with -
> > mgeneral-regs-only [PR target/94743]
> >
> > On Tue, 30 Jun 2020 at 15:16, Kyrylo Tkachov <Kyrylo.Tkachov@arm.com>
> > wrote:
> > >
> > > Hi Christophe,
> > >
> > > Sorry for the delay.
> > >
> > > > -----Original Message-----
> > > > From: Gcc-patches <gcc-patches-bounces@gcc.gnu.org> On Behalf Of
> > > > Christophe Lyon via Gcc-patches
> > > > Sent: 29 April 2020 16:19
> > > > To: gcc-patches@gcc.gnu.org
> > > > Subject: [PATCH] arm: Warn if IRQ handler is not compiled with -
> > mgeneral-
> > > > regs-only [PR target/94743]
> > > >
> > > > The interrupt attribute does not guarantee that the FP registers are
> > > > saved, which can result in problems difficult to debug.
> > > >
> > > > Saving the FP registers and status registers can be a large penalty,
> > > > so it's probably not desirable to do that all the time.
> > > >
> > > > If the handler calls other functions, we'd likely need to save all of
> > > > them, for lack of knowledge of which registers they actually use.
> > > >
> > > > This is even more obscure for the end-user when the compiler inserts
> > > > calls to helper functions such as memcpy (some multilibs do use FP
> > > > registers to speed it up).
> > > >
> > > > In the PR, we discussed adding routines in libgcc to save the FP
> > > > context and saving only locally-clobbered FP registers, but I think
> > > > this is too intrusive for stage 4.
> > > >
> > > > In the mean time, emit a warning to suggest re-compiling with
> > > > -mgeneral-regs-only. Note that this can lead to errors if the code
> > > > uses floating-point and -mfloat-abi=hard, eg:
> > > > argument of type 'double' not permitted with -mgeneral-regs-only
> > > >
> > > > This can be troublesome for the user, but at least this would make
> > > > them aware of the latent issue.
> > > >
> > > > The patch adds two testcases:
> > > > - pr94734-1.c checks that a warning is emitted. One function can make
> > > >   implicit calls to runtime floating-point routines, the other one
> > > >   doesn't. We can improve the diagnostic later not to warn in the
> > > >   second case.
> > > >
> > > > - pr94734-2.c checks that no warning is emitted when using
> > > >   -mgeneral-regs-only.
> > > >
> > > > 2020-04-29  Christophe Lyon  <christophe.lyon@linaro.org>
> > > >
> > > >       PR target/94743
> > > >       gcc/
> > > >       * config/arm/arm.c (arm_handle_isr_attribute): Warn if
> > > >       -mgeneral-regs-only is not used.
> > > >
> > > >       gcc/testsuite/
> > > >       * gcc.target/arm/pr94743-1.c: New test.
> > > >       * gcc.target/arm/pr94743-2.c: New test.
> > > > ---
> > > >  gcc/config/arm/arm.c                     |  5 +++++
> > > >  gcc/testsuite/gcc.target/arm/pr94743-1.c | 20 ++++++++++++++++++++
> > > >  gcc/testsuite/gcc.target/arm/pr94743-2.c | 17 +++++++++++++++++
> > > >  3 files changed, 42 insertions(+)
> > > >  create mode 100644 gcc/testsuite/gcc.target/arm/pr94743-1.c
> > > >  create mode 100644 gcc/testsuite/gcc.target/arm/pr94743-2.c
> > > >
> > > > diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
> > > > index 6a6e804..34aad1d 100644
> > > > --- a/gcc/config/arm/arm.c
> > > > +++ b/gcc/config/arm/arm.c
> > > > @@ -7176,6 +7176,11 @@ arm_handle_isr_attribute (tree *node, tree
> > name,
> > > > tree args, int flags,
> > > >                  name);
> > > >         *no_add_attrs = true;
> > > >       }
> > > > +      else if (TARGET_VFP_BASE)
> > > > +     {
> > > > +       warning (OPT_Wattributes, "FP registers might be clobbered
> > > > despite %qE attribute: compile with -mgeneral-regs-only",
> > > > +                name);
> > > > +     }
> > >
> > > Let's use %< and %> to quote -mgeneral-regs-only properly.
> > > Ok with that change.
> >
> > Hi Kyrill,
> >
> > Thanks for the review, however I have posted v2 here:
> > https://gcc.gnu.org/pipermail/gcc-patches/2020-May/545747.html
> > (you approved v1)
> >
> > It includes a few more testcases and updates to existing ones.
> >
> > Is v2 OK with the quotation marks fixed?
> >
>
> Oops, sorry. Yes that looks ok too (with the quotation fixed).
> Kyrill
>

Thanks, pushed as r11-1732.
There were two follow-ups: r11-1752 because I forgot to update the
expected warning message in the testcases after I changed the
quotation)
and r11-1759 because I missed that gcc.target/arm/handler-align.c has
to be compiled with -mgeneral-regs-only like other testcases.

Sorry for the noise,

Christophe

> > Thanks
> >
> > Christophe
> >
> > > Thanks,
> > > Kyrill
> > >
> > > >        /* FIXME: the argument if any is checked for type attributes;
> > > >        should it be checked for decl ones?  */
> > > >      }
> > > > diff --git a/gcc/testsuite/gcc.target/arm/pr94743-1.c
> > > > b/gcc/testsuite/gcc.target/arm/pr94743-1.c
> > > > new file mode 100644
> > > > index 0000000..67700c6
> > > > --- /dev/null
> > > > +++ b/gcc/testsuite/gcc.target/arm/pr94743-1.c
> > > > @@ -0,0 +1,20 @@
> > > > +/* PR target/94743 */
> > > > +/* { dg-do compile } */
> > > > +
> > > > +typedef struct {
> > > > +  double fpdata[32];
> > > > +} dummy_t;
> > > > +
> > > > +dummy_t global_d;
> > > > +dummy_t global_d1;
> > > > +
> > > > +__attribute__ ((interrupt("IRQ"))) void IRQ_HDLR_Test(void)
> > > > +{ /* { dg-warning { FP registers might be clobbered despite 'interrupt'
> > > > attribute: compile with -mgeneral-regs-only} "" { target *-*-* } . } */
> > > > +  global_d.fpdata[3] += global_d.fpdata[3] * global_d1.fpdata[3];
> > > > +}
> > > > +
> > > > +
> > > > +__attribute__ ((interrupt("IRQ"))) void IRQ_HDLR_Test2(void)
> > > > +{ /* { dg-warning { FP registers might be clobbered despite 'interrupt'
> > > > attribute: compile with -mgeneral-regs-only} "" { target *-*-* } . } */
> > > > +  global_d.fpdata[3] = 1.0;
> > > > +}
> > > > diff --git a/gcc/testsuite/gcc.target/arm/pr94743-2.c
> > > > b/gcc/testsuite/gcc.target/arm/pr94743-2.c
> > > > new file mode 100644
> > > > index 0000000..745fd36
> > > > --- /dev/null
> > > > +++ b/gcc/testsuite/gcc.target/arm/pr94743-2.c
> > > > @@ -0,0 +1,17 @@
> > > > +/* PR target/94743 */
> > > > +/* { dg-do compile } */
> > > > +/* { dg-options "-mgeneral-regs-only" } */
> > > > +
> > > > +typedef struct {
> > > > +  /* Do not use floating-point types, which are not be compatible with
> > > > +     -mgeneral-regs-only under -mfloat-abi=hard */
> > > > +  int fpdata[32];
> > > > +} dummy_t;
> > > > +
> > > > +dummy_t global_d;
> > > > +dummy_t global_d1;
> > > > +
> > > > +__attribute__ ((interrupt("IRQ"))) void IRQ_HDLR_Test(void)
> > > > +{
> > > > +  global_d.fpdata[3] += global_d.fpdata[3] * global_d1.fpdata[3];
> > > > +}
> > > > --
> > > > 2.7.4
> > >