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-rw-r--r--gcc/ChangeLog13
-rw-r--r--gcc/c-common.c4
-rw-r--r--gcc/c-decl.c8
-rw-r--r--gcc/c.opt4
-rw-r--r--gcc/cp/ChangeLog5
-rw-r--r--gcc/cp/class.c3
-rw-r--r--gcc/doc/extend.texi6
-rw-r--r--gcc/doc/invoke.texi23
-rw-r--r--gcc/stor-layout.c20
-rw-r--r--gcc/testsuite/ChangeLog7
-rw-r--r--gcc/testsuite/g++.dg/ext/bitfield2.C12
-rw-r--r--gcc/testsuite/g++.dg/ext/bitfield3.C11
-rw-r--r--gcc/testsuite/g++.dg/ext/bitfield4.C11
-rw-r--r--gcc/testsuite/g++.dg/ext/bitfield5.C11
-rw-r--r--gcc/testsuite/gcc.dg/bitfld-15.c12
-rw-r--r--gcc/testsuite/gcc.dg/bitfld-16.c11
-rw-r--r--gcc/testsuite/gcc.dg/bitfld-17.c11
-rw-r--r--gcc/testsuite/gcc.dg/bitfld-18.c11
18 files changed, 174 insertions, 9 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 3136439..2cfe41a 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,16 @@
+2009-01-22 Adam Nemet <anemet@caviumnetworks.com>
+
+ * c-decl.c (finish_struct): Move code to set DECL_PACKED after
+ DECL_BIT_FIELD is alreay known. Also inherit packed for bitfields
+ regardless of their type.
+ * c-common.c (handle_packed_attribute): Don't ignore packed on
+ bitfields.
+ * c.opt (Wpacked-bitfield-compat): New warning option.
+ * stor-layout.c (place_field): Warn if offset of a field changed.
+ * doc/extend.texi (packed): Mention the ABI change.
+ * doc/invoke.texi (-Wpacked-bitfield-compat): Document.
+ (Warning Options): Add it to the list.
+
2009-01-22 H.J. Lu <hongjiu.lu@intel.com>
* c-opts.c (c_common_post_options): Fix a typo in comments.
diff --git a/gcc/c-common.c b/gcc/c-common.c
index 5eed1dc..81992d4 100644
--- a/gcc/c-common.c
+++ b/gcc/c-common.c
@@ -5113,7 +5113,9 @@ handle_packed_attribute (tree *node, tree name, tree ARG_UNUSED (args),
}
else if (TREE_CODE (*node) == FIELD_DECL)
{
- if (TYPE_ALIGN (TREE_TYPE (*node)) <= BITS_PER_UNIT)
+ if (TYPE_ALIGN (TREE_TYPE (*node)) <= BITS_PER_UNIT
+ /* Still pack bitfields. */
+ && ! DECL_INITIAL (*node))
warning (OPT_Wattributes,
"%qE attribute ignored for field of type %qT",
name, TREE_TYPE (*node));
diff --git a/gcc/c-decl.c b/gcc/c-decl.c
index 7f7f2b0..6ebee1a 100644
--- a/gcc/c-decl.c
+++ b/gcc/c-decl.c
@@ -5564,9 +5564,6 @@ finish_struct (tree t, tree fieldlist, tree attributes)
DECL_CONTEXT (x) = t;
- if (TYPE_PACKED (t) && TYPE_ALIGN (TREE_TYPE (x)) > BITS_PER_UNIT)
- DECL_PACKED (x) = 1;
-
/* If any field is const, the structure type is pseudo-const. */
if (TREE_READONLY (x))
C_TYPE_FIELDS_READONLY (t) = 1;
@@ -5598,6 +5595,11 @@ finish_struct (tree t, tree fieldlist, tree attributes)
SET_DECL_C_BIT_FIELD (x);
}
+ if (TYPE_PACKED (t)
+ && (DECL_BIT_FIELD (x)
+ || TYPE_ALIGN (TREE_TYPE (x)) > BITS_PER_UNIT))
+ DECL_PACKED (x) = 1;
+
/* Detect flexible array member in an invalid context. */
if (TREE_CODE (TREE_TYPE (x)) == ARRAY_TYPE
&& TYPE_SIZE (TREE_TYPE (x)) == NULL_TREE
diff --git a/gcc/c.opt b/gcc/c.opt
index 1888ecd..75b7042 100644
--- a/gcc/c.opt
+++ b/gcc/c.opt
@@ -364,6 +364,10 @@ Woverride-init
C ObjC Var(warn_override_init) Init(-1) Warning
Warn about overriding initializers without side effects
+Wpacked-bitfield-compat
+C ObjC C++ ObjC++ Var(warn_packed_bitfield_compat) Init(1) Warning
+Warn about packed bit-fields whose offset changed in GCC 4.4
+
Wparentheses
C ObjC C++ ObjC++ Var(warn_parentheses) Warning
Warn about possibly missing parentheses
diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index a7d18d2..876cb7f 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,8 @@
+2009-01-22 Adam Nemet <anemet@caviumnetworks.com>
+
+ * class.c (check_field_decls): Also inherit packed for bitfields
+ regardless of their type.
+
2009-01-22 Dodji Seketeli <dodji@redhat.com>
PR c++/38930
diff --git a/gcc/cp/class.c b/gcc/cp/class.c
index 8d326f2..f56edc3 100644
--- a/gcc/cp/class.c
+++ b/gcc/cp/class.c
@@ -2974,7 +2974,8 @@ check_field_decls (tree t, tree *access_decls,
x);
cant_pack = 1;
}
- else if (TYPE_ALIGN (TREE_TYPE (x)) > BITS_PER_UNIT)
+ else if (DECL_C_BIT_FIELD (x)
+ || TYPE_ALIGN (TREE_TYPE (x)) > BITS_PER_UNIT)
DECL_PACKED (x) = 1;
}
diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi
index 264e88a..79a8c2e 100644
--- a/gcc/doc/extend.texi
+++ b/gcc/doc/extend.texi
@@ -3824,6 +3824,12 @@ struct foo
@};
@end smallexample
+@emph{Note:} The 4.1, 4.2 and 4.3 series of GCC ignore the
+@code{packed} attribute on bit-fields of type @code{char}. This has
+been fixed in GCC 4.4 but the change can lead to differences in the
+structure layout. See the documention of
+@option{-Wpacked-bitfield-compat} for more information.
+
@item section ("@var{section-name}")
@cindex @code{section} variable attribute
Normally, the compiler places the objects it generates in sections like
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index b0e274c..247782a 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -249,7 +249,7 @@ Objective-C and Objective-C++ Dialects}.
-Wmissing-format-attribute -Wmissing-include-dirs @gol
-Wmissing-noreturn -Wno-mudflap @gol
-Wno-multichar -Wnonnull -Wno-overflow @gol
--Woverlength-strings -Wpacked -Wpadded @gol
+-Woverlength-strings -Wpacked -Wpacked-bitfield-compat -Wpadded @gol
-Wparentheses -Wpedantic-ms-format -Wno-pedantic-ms-format @gol
-Wpointer-arith -Wno-pointer-to-int-cast @gol
-Wredundant-decls @gol
@@ -3974,6 +3974,27 @@ struct bar @{
@end group
@end smallexample
+@item -Wpacked-bitfield-compat
+@opindex Wpacked-bitfield-compat
+@opindex Wno-packed-bitfield-compat
+The 4.1, 4.2 and 4.3 series of GCC ignore the @code{packed} attribute
+on bit-fields of type @code{char}. This has been fixed in GCC 4.4 but
+the change can lead to differences in the structure layout. GCC
+informs you when the offset of such a field has changed in GCC 4.4.
+For example there is no longer a 4-bit padding between field @code{a}
+and @code{b} in this structure:
+
+@smallexample
+struct foo
+@{
+ char a:4;
+ char b:8;
+@} __attribute__ ((packed));
+@end smallexample
+
+This warning is enabled by default. Use
+@option{-Wno-packed-bitfield-compat} to disable this warning.
+
@item -Wpadded
@opindex Wpadded
@opindex Wno-padded
diff --git a/gcc/stor-layout.c b/gcc/stor-layout.c
index 0e7caa5..bf896db 100644
--- a/gcc/stor-layout.c
+++ b/gcc/stor-layout.c
@@ -937,7 +937,9 @@ place_field (record_layout_info rli, tree field)
&& TREE_CODE (field) == FIELD_DECL
&& type != error_mark_node
&& DECL_BIT_FIELD (field)
- && ! DECL_PACKED (field)
+ && (! DECL_PACKED (field)
+ /* Enter for these packed fields only to issue a warning. */
+ || TYPE_ALIGN (type) <= BITS_PER_UNIT)
&& maximum_field_alignment == 0
&& ! integer_zerop (DECL_SIZE (field))
&& host_integerp (DECL_SIZE (field), 1)
@@ -958,9 +960,21 @@ place_field (record_layout_info rli, tree field)
/* A bit field may not span more units of alignment of its type
than its type itself. Advance to next boundary if necessary. */
if (excess_unit_span (offset, bit_offset, field_size, type_align, type))
- rli->bitpos = round_up (rli->bitpos, type_align);
+ {
+ if (DECL_PACKED (field))
+ {
+ if (warn_packed_bitfield_compat)
+ inform
+ (input_location,
+ "Offset of packed bit-field %qD has changed in GCC 4.4",
+ field);
+ }
+ else
+ rli->bitpos = round_up (rli->bitpos, type_align);
+ }
- TYPE_USER_ALIGN (rli->t) |= TYPE_USER_ALIGN (type);
+ if (! DECL_PACKED (field))
+ TYPE_USER_ALIGN (rli->t) |= TYPE_USER_ALIGN (type);
}
#endif
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 37c8b09..bbf10c4 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,10 @@
+2009-01-22 Adam Nemet <anemet@caviumnetworks.com>
+
+ * gcc.dg/bitfld-15.c, gcc.dg/bitfld-16.c,
+ gcc.dg/bitfld-17.c,gcc.dg/bitfld-18.c: New tests.
+ * g++.dg/ext/bitfield2.C, g++.dg/ext/bitfield3.C,
+ g++.dg/ext/bitfield4.C, g++.dg/ext/bitfield5.C: New tests.
+
2009-01-22 Steve Ellcey <sje@cup.hp.com>
* gcc.dg/pr35729.c: Make test x86 specific.
diff --git a/gcc/testsuite/g++.dg/ext/bitfield2.C b/gcc/testsuite/g++.dg/ext/bitfield2.C
new file mode 100644
index 0000000..2b827a3
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/bitfield2.C
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+/* Remove pedantic. Allow the GCC extension to use char for bitfields. */
+/* { dg-options "" } */
+
+struct t
+{ /* { dg-message "note: Offset of packed bit-field 't::b' has changed in GCC 4.4" "" } */
+ char a:4;
+ char b:8;
+ char c:4;
+} __attribute__ ((packed));
+
+int assrt[sizeof (struct t) == 2 ? 1 : -1];
diff --git a/gcc/testsuite/g++.dg/ext/bitfield3.C b/gcc/testsuite/g++.dg/ext/bitfield3.C
new file mode 100644
index 0000000..3b30cc9
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/bitfield3.C
@@ -0,0 +1,11 @@
+/* { dg-do compile } */
+/* { dg-options "-Wno-packed-bitfield-compat" } */
+
+struct t
+{
+ char a:4;
+ char b:8;
+ char c:4;
+} __attribute__ ((packed));
+
+int assrt[sizeof (struct t) == 2 ? 1 : -1];
diff --git a/gcc/testsuite/g++.dg/ext/bitfield4.C b/gcc/testsuite/g++.dg/ext/bitfield4.C
new file mode 100644
index 0000000..f5fbd82
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/bitfield4.C
@@ -0,0 +1,11 @@
+/* { dg-do compile } */
+/* { dg-options "" } */
+
+struct t
+{ /* { dg-message "note: Offset of packed bit-field 't::b' has changed in GCC 4.4" "" } */
+ char a:4;
+ char b:8 __attribute__ ((packed));
+ char c:4;
+};
+
+int assrt[sizeof (struct t) == 2 ? 1 : -1];
diff --git a/gcc/testsuite/g++.dg/ext/bitfield5.C b/gcc/testsuite/g++.dg/ext/bitfield5.C
new file mode 100644
index 0000000..2cd8e7d
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/bitfield5.C
@@ -0,0 +1,11 @@
+/* { dg-do compile } */
+/* { dg-options "-Wno-packed-bitfield-compat" } */
+
+struct t
+{
+ char a:4;
+ char b:8 __attribute__ ((packed));
+ char c:4;
+};
+
+int assrt[sizeof (struct t) == 2 ? 1 : -1];
diff --git a/gcc/testsuite/gcc.dg/bitfld-15.c b/gcc/testsuite/gcc.dg/bitfld-15.c
new file mode 100644
index 0000000..bceeead
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/bitfld-15.c
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+/* Remove pedantic. Allow the GCC extension to use char for bitfields. */
+/* { dg-options "" } */
+
+struct t
+{
+ char a:4;
+ char b:8;
+ char c:4;
+} __attribute__ ((packed)); /* { dg-message "note: Offset of packed bit-field 'b' has changed in GCC 4.4" "" } */
+
+int assrt[sizeof (struct t) == 2 ? 1 : -1];
diff --git a/gcc/testsuite/gcc.dg/bitfld-16.c b/gcc/testsuite/gcc.dg/bitfld-16.c
new file mode 100644
index 0000000..3b30cc9
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/bitfld-16.c
@@ -0,0 +1,11 @@
+/* { dg-do compile } */
+/* { dg-options "-Wno-packed-bitfield-compat" } */
+
+struct t
+{
+ char a:4;
+ char b:8;
+ char c:4;
+} __attribute__ ((packed));
+
+int assrt[sizeof (struct t) == 2 ? 1 : -1];
diff --git a/gcc/testsuite/gcc.dg/bitfld-17.c b/gcc/testsuite/gcc.dg/bitfld-17.c
new file mode 100644
index 0000000..88ec199
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/bitfld-17.c
@@ -0,0 +1,11 @@
+/* { dg-do compile } */
+/* { dg-options "" } */
+
+struct t
+{
+ char a:4;
+ char b:8 __attribute__ ((packed));
+ char c:4;
+}; /* { dg-message "note: Offset of packed bit-field 'b' has changed in GCC 4.4" "" } */
+
+int assrt[sizeof (struct t) == 2 ? 1 : -1];
diff --git a/gcc/testsuite/gcc.dg/bitfld-18.c b/gcc/testsuite/gcc.dg/bitfld-18.c
new file mode 100644
index 0000000..2cd8e7d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/bitfld-18.c
@@ -0,0 +1,11 @@
+/* { dg-do compile } */
+/* { dg-options "-Wno-packed-bitfield-compat" } */
+
+struct t
+{
+ char a:4;
+ char b:8 __attribute__ ((packed));
+ char c:4;
+};
+
+int assrt[sizeof (struct t) == 2 ? 1 : -1];
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