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* [PATCH] Print padding size when aligning struct member
@ 2023-02-07 12:41 Vít Kabele
  2023-02-07 13:08 ` Andreas Schwab
  0 siblings, 1 reply; 6+ messages in thread
From: Vít Kabele @ 2023-02-07 12:41 UTC (permalink / raw)
  To: gcc-patches; +Cc: vit, Vít Kabele

Announce the size of introduced padding when compiling
with -Wpadded.

gcc/ChangeLog:

	* stor-layout.cc (place_field): Change warning message format

gcc/testsuite/ChangeLog:

	* c-c++-common/Wpadded.c: Add new testcase
	* gcc.dg/Wpadded.c: Update the expected warning message

Signed-off-by: Vít Kabele <vit.kabele@sysgo.com>
---
 gcc/stor-layout.cc                   | 2 +-
 gcc/testsuite/c-c++-common/Wpadded.c | 1 +
 gcc/testsuite/gcc.dg/Wpadded.c       | 2 +-
 3 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/gcc/stor-layout.cc b/gcc/stor-layout.cc
index 45bf2d18639..fb1948b94af 100644
--- a/gcc/stor-layout.cc
+++ b/gcc/stor-layout.cc
@@ -1346,7 +1346,7 @@ place_field (record_layout_info rli, tree field)
       if (!targetm.ms_bitfield_layout_p (rli->t)
 	  && DECL_SOURCE_LOCATION (field) != BUILTINS_LOCATION
 	  && !TYPE_ARTIFICIAL (rli->t))
-	warning (OPT_Wpadded, "padding struct to align %q+D", field);
+		warning (OPT_Wpadded, "padding struct with %d bytes to align %q+D", (desired_align - known_align)/8, field);
 
       /* If the alignment is still within offset_align, just align
 	 the bit position.  */
diff --git a/gcc/testsuite/c-c++-common/Wpadded.c b/gcc/testsuite/c-c++-common/Wpadded.c
index c5be4686822..35ff013026f 100644
--- a/gcc/testsuite/c-c++-common/Wpadded.c
+++ b/gcc/testsuite/c-c++-common/Wpadded.c
@@ -11,4 +11,5 @@
  * 4 byte fields to 2 byte boundary.
  */
 struct S { __UINT32_TYPE__ i; char c; } __attribute__((aligned(4))); /* { dg-warning "padding struct size to alignment boundary with 3 bytes" } */
+struct R { char c; __UINT32_TYPE__ i; } __attribute__((aligned(4))); /* { dg-warning "padding struct with 3 bytes to align 'i'" } */
 
diff --git a/gcc/testsuite/gcc.dg/Wpadded.c b/gcc/testsuite/gcc.dg/Wpadded.c
index 70fcd79a6d4..357e7f61e4a 100644
--- a/gcc/testsuite/gcc.dg/Wpadded.c
+++ b/gcc/testsuite/gcc.dg/Wpadded.c
@@ -10,5 +10,5 @@
 
 struct foo {
   char bar;
-  long baz; /* { dg-warning "padding struct to align" ""  { target { ! default_packed } } } */
+  long baz; /* { dg-warning "padding struct with 7 bytes to align" ""  { target { ! default_packed } } } */
 } futz;
-- 
2.30.2


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] Print padding size when aligning struct member
  2023-02-07 12:41 [PATCH] Print padding size when aligning struct member Vít Kabele
@ 2023-02-07 13:08 ` Andreas Schwab
  2023-02-07 14:09   ` Vit Kabele
  2023-02-24  7:28   ` [PATCH v2] " Vít Kabele
  0 siblings, 2 replies; 6+ messages in thread
From: Andreas Schwab @ 2023-02-07 13:08 UTC (permalink / raw)
  To: Vít Kabele; +Cc: gcc-patches, vit

On Feb 07 2023, Vít Kabele wrote:

> diff --git a/gcc/testsuite/gcc.dg/Wpadded.c b/gcc/testsuite/gcc.dg/Wpadded.c
> index 70fcd79a6d4..357e7f61e4a 100644
> --- a/gcc/testsuite/gcc.dg/Wpadded.c
> +++ b/gcc/testsuite/gcc.dg/Wpadded.c
> @@ -10,5 +10,5 @@
>  
>  struct foo {
>    char bar;
> -  long baz; /* { dg-warning "padding struct to align" ""  { target { ! default_packed } } } */
> +  long baz; /* { dg-warning "padding struct with 7 bytes to align" ""  { target { ! default_packed } } } */

The actual amount of padding is target dependent.

-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] Print padding size when aligning struct member
  2023-02-07 13:08 ` Andreas Schwab
@ 2023-02-07 14:09   ` Vit Kabele
  2023-02-24  7:28   ` [PATCH v2] " Vít Kabele
  1 sibling, 0 replies; 6+ messages in thread
From: Vit Kabele @ 2023-02-07 14:09 UTC (permalink / raw)
  To: Andreas Schwab; +Cc: gcc-patches, vit

On Tue, Feb 07, 2023 at 02:08:35PM +0100, Andreas Schwab wrote:
> On Feb 07 2023, Vít Kabele wrote:
> 
> > diff --git a/gcc/testsuite/gcc.dg/Wpadded.c b/gcc/testsuite/gcc.dg/Wpadded.c
> > index 70fcd79a6d4..357e7f61e4a 100644
> > --- a/gcc/testsuite/gcc.dg/Wpadded.c
> > +++ b/gcc/testsuite/gcc.dg/Wpadded.c
> > @@ -10,5 +10,5 @@
> >  
> >  struct foo {
> >    char bar;
> > -  long baz; /* { dg-warning "padding struct to align" ""  { target { ! default_packed } } } */
> > +  long baz; /* { dg-warning "padding struct with 7 bytes to align" ""  { target { ! default_packed } } } */
> 
> The actual amount of padding is target dependent.
Ah sorry, would removing everything after `with...` be ok?

Like this:
> +  long baz; /* { dg-warning "padding struct with" ""  { target { ! default_packed } } } */

-- 
Best regards,
Vit Kabele

^ permalink raw reply	[flat|nested] 6+ messages in thread

* [PATCH v2] Print padding size when aligning struct member
  2023-02-07 13:08 ` Andreas Schwab
  2023-02-07 14:09   ` Vit Kabele
@ 2023-02-24  7:28   ` Vít Kabele
  2023-03-11 15:35     ` Jeff Law
  1 sibling, 1 reply; 6+ messages in thread
From: Vít Kabele @ 2023-02-24  7:28 UTC (permalink / raw)
  To: gcc-patches; +Cc: vit, Vít Kabele

Hello,

I changed the tested pattern to match even on targets with different
alignment.

BR,
VK

-- >8 --

Announce the size of introduced padding when compiling
with -Wpadded.

gcc/ChangeLog:

	* stor-layout.cc (place_field): Change warning message format

gcc/testsuite/ChangeLog:

	* c-c++-common/Wpadded.c: Add new testcase
	* gcc.dg/Wpadded.c: Update the expected warning message

Signed-off-by: Vít Kabele <vit.kabele@sysgo.com>
---
 gcc/stor-layout.cc                   | 2 +-
 gcc/testsuite/c-c++-common/Wpadded.c | 1 +
 gcc/testsuite/gcc.dg/Wpadded.c       | 2 +-
 3 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/gcc/stor-layout.cc b/gcc/stor-layout.cc
index 45bf2d18639..1d2bd61eeae 100644
--- a/gcc/stor-layout.cc
+++ b/gcc/stor-layout.cc
@@ -1346,7 +1346,7 @@ place_field (record_layout_info rli, tree field)
       if (!targetm.ms_bitfield_layout_p (rli->t)
 	  && DECL_SOURCE_LOCATION (field) != BUILTINS_LOCATION
 	  && !TYPE_ARTIFICIAL (rli->t))
-	warning (OPT_Wpadded, "padding struct to align %q+D", field);
+	warning (OPT_Wpadded, "padding struct with %d bytes to align %q+D", (desired_align - known_align)/8, field);
 
       /* If the alignment is still within offset_align, just align
 	 the bit position.  */
diff --git a/gcc/testsuite/c-c++-common/Wpadded.c b/gcc/testsuite/c-c++-common/Wpadded.c
index c5be4686822..0818ea03690 100644
--- a/gcc/testsuite/c-c++-common/Wpadded.c
+++ b/gcc/testsuite/c-c++-common/Wpadded.c
@@ -11,4 +11,5 @@
  * 4 byte fields to 2 byte boundary.
  */
 struct S { __UINT32_TYPE__ i; char c; } __attribute__((aligned(4))); /* { dg-warning "padding struct size to alignment boundary with 3 bytes" } */
+struct R { char c; __UINT32_TYPE__ i; } __attribute__((aligned(4))); /* { dg-warning "padding struct with" } */
 
diff --git a/gcc/testsuite/gcc.dg/Wpadded.c b/gcc/testsuite/gcc.dg/Wpadded.c
index 70fcd79a6d4..218b37d1abc 100644
--- a/gcc/testsuite/gcc.dg/Wpadded.c
+++ b/gcc/testsuite/gcc.dg/Wpadded.c
@@ -10,5 +10,5 @@
 
 struct foo {
   char bar;
-  long baz; /* { dg-warning "padding struct to align" ""  { target { ! default_packed } } } */
+  long baz; /* { dg-warning "padding struct with" ""  { target { ! default_packed } } } */
 } futz;
-- 
2.30.2


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH v2] Print padding size when aligning struct member
  2023-02-24  7:28   ` [PATCH v2] " Vít Kabele
@ 2023-03-11 15:35     ` Jeff Law
  2023-03-28 14:24       ` Vit Kabele
  0 siblings, 1 reply; 6+ messages in thread
From: Jeff Law @ 2023-03-11 15:35 UTC (permalink / raw)
  To: Vít Kabele, gcc-patches; +Cc: vit



On 2/24/23 00:28, Vít Kabele wrote:
> Hello,
> 
> I changed the tested pattern to match even on targets with different
> alignment.
So this needs to wait for stage1 development to open -- we're in 
regression bugfixing phase only right now.  I would expect that to 
happen in April/May.

You might consider changing the other similar message you added last 
year to finalize_record_size to use the same format as this message for 
the sake of consistency.

Jeff

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH v2] Print padding size when aligning struct member
  2023-03-11 15:35     ` Jeff Law
@ 2023-03-28 14:24       ` Vit Kabele
  0 siblings, 0 replies; 6+ messages in thread
From: Vit Kabele @ 2023-03-28 14:24 UTC (permalink / raw)
  To: Jeff Law, gcc-patches; +Cc: vit

Hello,

On Sat, Mar 11, 2023 at 08:35:53AM -0700, Jeff Law wrote:
> On 2/24/23 00:28, Vít Kabele wrote:
> You might consider changing the other similar message you added last year to
> finalize_record_size to use the same format as this message for the sake of
> consistency.
For example like this?

- padding struct with %d bytes to align %q+D
+ padding struct to align %q+D with %d bytes

to be consistent with:

padding struct size to alignment boundary with %E bytes

-- 
Best regards,
Vit Kabele

^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2023-03-28 14:24 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-02-07 12:41 [PATCH] Print padding size when aligning struct member Vít Kabele
2023-02-07 13:08 ` Andreas Schwab
2023-02-07 14:09   ` Vit Kabele
2023-02-24  7:28   ` [PATCH v2] " Vít Kabele
2023-03-11 15:35     ` Jeff Law
2023-03-28 14:24       ` Vit Kabele

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