[PATCH] tree-optimization/103456 - Record only successes from object_sizes_set

[PATCH] tree-optimization/103456 - Record only successes from object_sizes_set

[Siddhesh Poyarekar]

Avoid overwriting osi->changed if object_sizes_set does not update the
size, so that a previous success in the same pass is not overwritten.
This fixes the bootstrap-ubsan build config, which was failing due to
incorrect object size.

Also completed a bootstrap on x86_64 which didn't show any new failures.

gcc/ChangeLog:

	PR tree-optimization/103456
	* tree-object-size.c (merge_object_sizes): Update osi->changed
	only if object_sizes_set succeeded.

gcc/testsuite/ChangeLog:

	PR tree-optimization/103456
	* gcc.dg/pr103456.c: New test.

Co-authored-by: Martin Liška <mliska@suse.cz>
Signed-off-by: Siddhesh Poyarekar <siddhesh@gotplt.org>
---
 gcc/testsuite/gcc.dg/pr103456.c | 21 +++++++++++++++++++++
 gcc/tree-object-size.c          |  3 ++-
 2 files changed, 23 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/gcc.dg/pr103456.c

diff --git a/gcc/testsuite/gcc.dg/pr103456.c b/gcc/testsuite/gcc.dg/pr103456.c
new file mode 100644
index 00000000000..20322fbaab1
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr103456.c
@@ -0,0 +1,21 @@
+/* PR tree-optimization/103456 */
+/* { dg-do compile } */
+/* { dg-options "-fsanitize=undefined -O -fdump-tree-objsz" } */
+
+static char *multilib_options = "m64/m32";
+
+void
+used_arg_t (void)
+{
+  char *q = multilib_options;
+  for (;;)
+    {
+      while (*q)
+	q++;
+      while (__builtin_strchr (q, '_') == 0)
+	while (*q)
+	  q++;
+    }
+}
+
+/* { dg-final { scan-tree-dump-not "maximum object size 0" "objsz1" } } */
diff --git a/gcc/tree-object-size.c b/gcc/tree-object-size.c
index 3780437ff91..b4881ef198f 100644
--- a/gcc/tree-object-size.c
+++ b/gcc/tree-object-size.c
@@ -854,7 +854,8 @@ merge_object_sizes (struct object_size_info *osi, tree dest, tree orig,
     orig_bytes = (offset > orig_bytes)
 		 ? HOST_WIDE_INT_0U : orig_bytes - offset;
 
-  osi->changed = object_sizes_set (osi, varno, orig_bytes);
+  if (object_sizes_set (osi, varno, orig_bytes))
+    osi->changed = true;
 
   return bitmap_bit_p (osi->reexamine, SSA_NAME_VERSION (orig));
 }
-- 
2.31.1

Re: [PATCH] tree-optimization/103456 - Record only successes from object_sizes_set

[Jakub Jelinek]

On Wed, Dec 01, 2021 at 09:47:21AM +0530, Siddhesh Poyarekar wrote:
> Avoid overwriting osi->changed if object_sizes_set does not update the
> size, so that a previous success in the same pass is not overwritten.
> This fixes the bootstrap-ubsan build config, which was failing due to
> incorrect object size.
> 
> Also completed a bootstrap on x86_64 which didn't show any new failures.
> 
> gcc/ChangeLog:
> 
> 	PR tree-optimization/103456
> 	* tree-object-size.c (merge_object_sizes): Update osi->changed
> 	only if object_sizes_set succeeded.
> 
> gcc/testsuite/ChangeLog:
> 
> 	PR tree-optimization/103456
> 	* gcc.dg/pr103456.c: New test.
> 
> Co-authored-by: Martin Liška <mliska@suse.cz>
> Signed-off-by: Siddhesh Poyarekar <siddhesh@gotplt.org>
> ---
>  gcc/testsuite/gcc.dg/pr103456.c | 21 +++++++++++++++++++++
>  gcc/tree-object-size.c          |  3 ++-
>  2 files changed, 23 insertions(+), 1 deletion(-)
>  create mode 100644 gcc/testsuite/gcc.dg/pr103456.c
> 
> diff --git a/gcc/testsuite/gcc.dg/pr103456.c b/gcc/testsuite/gcc.dg/pr103456.c
> new file mode 100644
> index 00000000000..20322fbaab1
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/pr103456.c

With -fsanitize=undefined that testcase belongs to
gcc/testsuite/gcc.dg/ubsan/pr103456.c, please move it there.

> @@ -0,0 +1,21 @@
> +/* PR tree-optimization/103456 */
> +/* { dg-do compile } */
> +/* { dg-options "-fsanitize=undefined -O -fdump-tree-objsz" } */
> +
> +static char *multilib_options = "m64/m32";
> +
> +void
> +used_arg_t (void)
> +{
> +  char *q = multilib_options;
> +  for (;;)
> +    {
> +      while (*q)
> +	q++;
> +      while (__builtin_strchr (q, '_') == 0)
> +	while (*q)
> +	  q++;
> +    }
> +}
> +
> +/* { dg-final { scan-tree-dump-not "maximum object size 0" "objsz1" } } */
> diff --git a/gcc/tree-object-size.c b/gcc/tree-object-size.c
> index 3780437ff91..b4881ef198f 100644
> --- a/gcc/tree-object-size.c
> +++ b/gcc/tree-object-size.c
> @@ -854,7 +854,8 @@ merge_object_sizes (struct object_size_info *osi, tree dest, tree orig,
>      orig_bytes = (offset > orig_bytes)
>  		 ? HOST_WIDE_INT_0U : orig_bytes - offset;
>  
> -  osi->changed = object_sizes_set (osi, varno, orig_bytes);
> +  if (object_sizes_set (osi, varno, orig_bytes))
> +    osi->changed = true;
>  
>    return bitmap_bit_p (osi->reexamine, SSA_NAME_VERSION (orig));
>  }

Otherwise LGTM.

	Jakub

[COMMITTED] tree-optimization/103456 - Record only successes from object_sizes_set

[Siddhesh Poyarekar]

Avoid overwriting osi->changed if object_sizes_set does not update the
size, so that a previous success in the same pass is not overwritten.
This fixes the bootstrap-ubsan build config, which was failing due to
incorrect object size.

gcc/ChangeLog:

	PR tree-optimization/103456
	* tree-object-size.c (merge_object_sizes): Update osi->changed
	only if object_sizes_set succeeded.

gcc/testsuite/ChangeLog:

	PR tree-optimization/103456
	* gcc.dg/ubsan/pr103456.c: New test.

Co-authored-by: Martin Liška <mliska@suse.cz>
Signed-off-by: Siddhesh Poyarekar <siddhesh@gotplt.org>
---
 gcc/testsuite/gcc.dg/ubsan/pr103456.c | 21 +++++++++++++++++++++
 gcc/tree-object-size.c                |  3 ++-
 2 files changed, 23 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/gcc.dg/ubsan/pr103456.c

diff --git a/gcc/testsuite/gcc.dg/ubsan/pr103456.c b/gcc/testsuite/gcc.dg/ubsan/pr103456.c
new file mode 100644
index 00000000000..20322fbaab1
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/ubsan/pr103456.c
@@ -0,0 +1,21 @@
+/* PR tree-optimization/103456 */
+/* { dg-do compile } */
+/* { dg-options "-fsanitize=undefined -O -fdump-tree-objsz" } */
+
+static char *multilib_options = "m64/m32";
+
+void
+used_arg_t (void)
+{
+  char *q = multilib_options;
+  for (;;)
+    {
+      while (*q)
+	q++;
+      while (__builtin_strchr (q, '_') == 0)
+	while (*q)
+	  q++;
+    }
+}
+
+/* { dg-final { scan-tree-dump-not "maximum object size 0" "objsz1" } } */
diff --git a/gcc/tree-object-size.c b/gcc/tree-object-size.c
index 3780437ff91..b4881ef198f 100644
--- a/gcc/tree-object-size.c
+++ b/gcc/tree-object-size.c
@@ -854,7 +854,8 @@ merge_object_sizes (struct object_size_info *osi, tree dest, tree orig,
     orig_bytes = (offset > orig_bytes)
 		 ? HOST_WIDE_INT_0U : orig_bytes - offset;
 
-  osi->changed = object_sizes_set (osi, varno, orig_bytes);
+  if (object_sizes_set (osi, varno, orig_bytes))
+    osi->changed = true;
 
   return bitmap_bit_p (osi->reexamine, SSA_NAME_VERSION (orig));
 }
-- 
2.31.1

[committed] testsuite: Fix up pr103456.c testcase [PR103456]

[Jakub Jelinek]

On Wed, Dec 01, 2021 at 02:01:59PM +0530, Siddhesh Poyarekar wrote:
> 	PR tree-optimization/103456
> 	* gcc.dg/ubsan/pr103456.c: New test.

ubsan.exp cycles through torture options, and that includes
-O2 -flto -fno-fat-lto-objects.  But with those options
tree dump scans don't work for post-IPA passes, for dg-do
compile tests nothing after IPA is done.  So we get an
unresolved testcase:
gcc.dg/ubsan/pr103456.c   -O2 -flto -fuse-linker-plugin -fno-fat-lto-objects  : dump file does not exist
UNRESOLVED: gcc.dg/ubsan/pr103456.c   -O2 -flto -fuse-linker-plugin -fno-fat-lto-objects   scan-tree-dump-not objsz1 "maximum object size 0"

Fixed by adding -ffat-lto-objects so that we perform the post-IPA
passes.

Tested on x86_64-linux, committed to trunk as obvious.

2021-12-03  Jakub Jelinek  <jakub@redhat.com>

	PR tree-optimization/103456
	* gcc.dg/ubsan/pr103456.c: Add -ffat-lto-objects to dg-options.

--- gcc/testsuite/gcc.dg/ubsan/pr103456.c.jj	2021-12-01 10:03:55.404029919 +0100
+++ gcc/testsuite/gcc.dg/ubsan/pr103456.c	2021-12-03 12:06:57.613750230 +0100
@@ -1,6 +1,6 @@
 /* PR tree-optimization/103456 */
 /* { dg-do compile } */
-/* { dg-options "-fsanitize=undefined -O -fdump-tree-objsz" } */
+/* { dg-options "-fsanitize=undefined -O -fdump-tree-objsz -ffat-lto-objects" } */
 
 static char *multilib_options = "m64/m32";
 


	Jakub