ubsan: Avoid -Wpadded warnings [PR94641]

-Wpadded warnings aren't really useful for the artificial types that GCC
lays out for ubsan.

2020-04-21  Jakub Jelinek  <jakub@redhat.com>

	PR c/94641
	* stor-layout.c (place_field, finalize_record_size): Don't emit
	-Wpadded warning on TYPE_ARTIFICIAL rli->t.
	* ubsan.c (ubsan_get_type_descriptor_type,
	ubsan_get_source_location_type, ubsan_create_data): Set
	TYPE_ARTIFICIAL.
	* asan.c (asan_global_struct): Likewise.

	* c-c++-common/ubsan/pr94641.c: New test.

(cherry picked from commit 73f8e9dca5ff891ed19001b213fd1f6ce31417e3)

diff --git a/gcc/asan.c b/gcc/asan.c
index 2baf06ffa7c43a7aea81386da04977c81a1a9722..7c392547c0e68dddf587f716c023e31990b6363c 100644 (file)
--- a/gcc/asan.c
+++ b/gcc/asan.c
@@ -2677,6 +2677,7 @@ asan_global_struct (void)
   TYPE_FIELDS (ret) = fields[0];
   TYPE_NAME (ret) = type_decl;
   TYPE_STUB_DECL (ret) = type_decl;
+  TYPE_ARTIFICIAL (ret) = 1;
   layout_type (ret);
   return ret;
 }

diff --git a/gcc/stor-layout.c b/gcc/stor-layout.c
index 5d6f2e0166cee4da93235c66dd0d3dfdeefff5a6..125fc66b5ce02e05368199598af5b800f3c6f273 100644 (file)
--- a/gcc/stor-layout.c
+++ b/gcc/stor-layout.c
@@ -1315,7 +1315,8 @@ place_field (record_layout_info rli, tree field)
         Bump the cumulative size to multiple of field alignment.  */
 
       if (!targetm.ms_bitfield_layout_p (rli->t)
-          && DECL_SOURCE_LOCATION (field) != BUILTINS_LOCATION)
+         && DECL_SOURCE_LOCATION (field) != BUILTINS_LOCATION
+         && !TYPE_ARTIFICIAL (rli->t))
        warning (OPT_Wpadded, "padding struct to align %q+D", field);
 
       /* If the alignment is still within offset_align, just align
@@ -1749,7 +1750,8 @@ finalize_record_size (record_layout_info rli)
 
   if (TREE_CONSTANT (unpadded_size)
       && simple_cst_equal (unpadded_size, TYPE_SIZE (rli->t)) == 0
-      && input_location != BUILTINS_LOCATION)
+      && input_location != BUILTINS_LOCATION
+      && !TYPE_ARTIFICIAL (rli->t))
     warning (OPT_Wpadded, "padding struct size to alignment boundary");
 
   if (warn_packed && TREE_CODE (rli->t) == RECORD_TYPE

diff --git a/gcc/testsuite/c-c++-common/ubsan/pr94641.c b/gcc/testsuite/c-c++-common/ubsan/pr94641.c
new file mode 100644 (file)
index 0000000..b41cb06
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/ubsan/pr94641.c
@@ -0,0 +1,11 @@
+/* PR c/94641 */
+/* { dg-do compile } */
+/* { dg-options "-fsanitize=undefined -Wpadded" } */
+
+void foo (void *) __attribute__((nonnull));
+
+void
+bar (void *p)
+{
+  foo (p);
+}

diff --git a/gcc/ubsan.c b/gcc/ubsan.c
index d2696302bd0b0ef39ba08913eb27796f72143586..5d4af79177c282457b84ba83da24efe52274e862 100644 (file)
--- a/gcc/ubsan.c
+++ b/gcc/ubsan.c
@@ -229,6 +229,7 @@ ubsan_get_type_descriptor_type (void)
   TYPE_FIELDS (ret) = fields[0];
   TYPE_NAME (ret) = type_decl;
   TYPE_STUB_DECL (ret) = type_decl;
+  TYPE_ARTIFICIAL (ret) = 1;
   layout_type (ret);
   ubsan_type_descriptor_type = ret;
   return ret;
@@ -277,6 +278,7 @@ ubsan_get_source_location_type (void)
   TYPE_FIELDS (ret) = fields[0];
   TYPE_NAME (ret) = type_decl;
   TYPE_STUB_DECL (ret) = type_decl;
+  TYPE_ARTIFICIAL (ret) = 1;
   layout_type (ret);
   ubsan_source_location_type = ret;
   return ret;
@@ -593,6 +595,7 @@ ubsan_create_data (const char *name, int loccnt, const location_t *ploc, ...)
   TYPE_FIELDS (ret) = fields[0];
   TYPE_NAME (ret) = type_decl;
   TYPE_STUB_DECL (ret) = type_decl;
+  TYPE_ARTIFICIAL (ret) = 1;
   layout_type (ret);
 
   /* Now, fill in the type.  */