procyberian/gcc
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

re PR other/54265 (Documentation of "preferred attribute syntax for Types" contradicts examples in info.)

Browse source 
2018-11-25  Sandra Loosemore  <sandra@codesourcery.com>

	PR other/54265

	gcc/
	* doc/extend.texi (Common Variable Attributes): Use preferred
	placement of type attributes in examples, plus whitespace fixes.
	(Type Attributes): Clarify why placement of attributes
	immediately after struct/union/enum keyword is preferred.
	(Common Type Attributes): Use preferred placement of type
	attributes in examples, plus more whitespace fixes.

From-SVN: r266440
This commit is contained in:
Sandra Loosemore 2018-11-25 16:10:34 -05:00 • committed by Sandra Loosemore
parent 537db3a2bc
commit 8f76a0895a
2 changed files with 27 additions and 16 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

10
gcc/ChangeLog
View file

@ -1,3 +1,13 @@
2018-11-25 Sandra Loosemore <sandra@codesourcery.com>
PR other/54265
* doc/extend.texi (Common Variable Attributes): Use preferred
placement of type attributes in examples, plus whitespace fixes.
(Type Attributes): Clarify why placement of attributes
immediately after struct/union/enum keyword is preferred.
(Common Type Attributes): Use preferred placement of type
attributes in examples, plus more whitespace fixes.
2018-11-25 Paul Koning <ni1d@arrl.net>
* config/pdp11/pdp11.h (TARGET_HAS_NO_HW_DIVIDE): Define.

33
gcc/doc/extend.texi
View file

@ -6177,7 +6177,7 @@ struct foo
@{
int i1;
int i2;
unsigned long long x __attribute__((warn_if_not_aligned(16)));
unsigned long long x __attribute__ ((warn_if_not_aligned (16)));
@};
@end smallexample
@ -6189,12 +6189,12 @@ The compiler also issues a warning, like @samp{warning: 'x' offset
the misaligned offset:
@smallexample
struct foo
struct __attribute__ ((aligned (16))) foo
@{
int i1;
int i2;
unsigned long long x __attribute__((warn_if_not_aligned(16)));
@} __attribute__((aligned(16)));
unsigned long long x __attribute__ ((warn_if_not_aligned (16)));
@};
@end smallexample
This warning can be disabled by @option{-Wno-if-not-aligned}.
@ -7019,9 +7019,10 @@ inside double parentheses.
You may specify type attributes in an enum, struct or union type
declaration or definition by placing them immediately after the
@code{struct}, @code{union} or @code{enum} keyword. A less preferred
syntax is to place them just past the closing curly brace of the
definition.
@code{struct}, @code{union} or @code{enum} keyword. You can also place
them just past the closing curly brace of the definition, but this is less
preferred because logically the type should be fully defined at
the closing brace.
You can also include type attributes in a @code{typedef} declaration.
@xref{Attribute Syntax}, for details of the exact syntax for using
@ -7053,7 +7054,7 @@ alignment for the target, which is often, but by no means always, 8 or 16
bytes. For example, the declarations:
@smallexample
struct S @{ short f[3]; @} __attribute__ ((aligned (8)));
struct __attribute__ ((aligned (8))) S @{ short f[3]; @};
typedef int more_aligned_int __attribute__ ((aligned (8)));
@end smallexample
@ -7084,7 +7085,7 @@ useful alignment for the target machine you are compiling for. For
example, you could write:
@smallexample
struct S @{ short f[3]; @} __attribute__ ((aligned));
struct __attribute__ ((aligned)) S @{ short f[3]; @};
@end smallexample
Whenever you leave out the alignment factor in an @code{aligned}
@ -7119,7 +7120,7 @@ by inherent limitations in your linker. On many systems, the linker is
only able to arrange for variables to be aligned up to a certain maximum
alignment. (For some linkers, the maximum supported alignment may
be very very small.) If your linker is only able to align variables
up to a maximum of 8-byte alignment, then specifying @code{aligned(16)}
up to a maximum of 8-byte alignment, then specifying @code{aligned (16)}
in an @code{__attribute__} still only provides you with 8-byte
alignment. See your linker documentation for further information.
@ -7137,7 +7138,7 @@ warning will be issued. For example, the declaration:
@smallexample
typedef unsigned long long __u64
__attribute__((aligned(4),warn_if_not_aligned(8)));
__attribute__((aligned (4), warn_if_not_aligned (8)));
struct foo
@{
@ -7156,12 +7157,12 @@ has the same alignment when @code{__u64} is aligned at either 4 or
8 bytes. Align @code{struct foo} to 8 bytes:
@smallexample
struct foo
struct __attribute__ ((aligned (8))) foo
@{
int i1;
int i2;
__u64 x;
@} __attribute__((aligned(8)));
@};
@end smallexample
@noindent
@ -7170,13 +7171,13 @@ silences the warning. The compiler also issues a warning, like
when the structure field has the misaligned offset:
@smallexample
struct foo
struct __attribute__ ((aligned (8))) foo
@{
int i1;
int i2;
int i3;
__u64 x;
@} __attribute__((aligned(8)));
@};
@end smallexample
This warning can be disabled by @option{-Wno-if-not-aligned}.
@ -7281,7 +7282,7 @@ special semantics.
Example of use:
@smallexample
typedef short __attribute__((__may_alias__)) short_a;
typedef short __attribute__ ((__may_alias__)) short_a;
int
main (void)