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PING^5 [PATCH, GCC 5] PR 70613, -fabi-version docs don't match implementation

Message ID CABXYE2WuUm5xu5F6oJKkFjXPJJ+VagHR0JJCaX8RmCo=G3pu3g@mail.gmail.com
State New
Headers show

Commit Message

Jim Wilson May 16, 2016, 10:35 p.m. UTC 
This is my fifth ping.  I just need someone to rubber stamp it so I
can check it in.

Maybe it would be easier if I volunteered to be a doc maintainer so I
can self approve it?

Jim

On Mon, May 9, 2016 at 4:21 PM, Jim Wilson <jim.wilson@linaro.org> wrote:
> On Mon, May 2, 2016 at 12:13 PM, Jim Wilson <jim.wilson@linaro.org> wrote:

>> Here is a patch to correct the -fabi-version docs on the GCC 5 branch.

>> https://gcc.gnu.org/ml/gcc-patches/2016-04/msg00480.html

>

> You can see the default -fabi-version in gcc/c-family/c-opts.c on the

> gcc-5 branch which has

>

>   /* Change flag_abi_version to be the actual current ABI level for the

>      benefit of c_cpp_builtins.  */

>   if (flag_abi_version == 0)

>     flag_abi_version = 9;

>

> You can see in the docs that -fabi-version only goes up to 8.

>     https://gcc.gnu.org/onlinedocs/gcc-5.3.0/gcc/C_002b_002b-Dialect-Options.html#C_002b_002b-Dialect-Options

>

> As for how we got here...

> I see that the patch for bug 65945 was back ported to the gcc-5

> branch, which required a partial backport of the patch for bug 44282,

> which added abi version 9.  The original patch for 44282 is missing

> the doc change.

>

> The missing doc change was then added here

>     https://gcc.gnu.org/viewcvs/gcc?view=revision&revision=228017

> which has the invoke.texi hunk we need, but is missing a ChangeLog

> entry for it.  So it appears all we need is a partial backport of this

> invoke.texi hunk.  This is mostly documenting a change to -Wabi, so we

> only need parts of two hunks that document -fabi-version=9 and mention

> gcc-5.2.

>

> The patch is attached again.

>

> Jim
diff mbox

Patch

Index: ChangeLog
===================================================================
--- ChangeLog	(revision 234867)
+++ ChangeLog	(working copy)
@@ -1,3 +1,12 @@ 
+2016-04-11  Jim Wilson  <jim.wilson@linaro.org>
+
+	Partial backport from trunk r228017.
+	2015-09-22  Jason Merrill  <jason@redhat.com>
+
+	PR c++/70613
+	* doc/invoke.texi (-fabi-version): Document version 9.
+	(-Wabi): Document version 9.  Mention version 8 is default for GCC 5.1.
+
 2016-04-09  Oleg Endo  <olegendo@gcc.gnu.org>
 
 	Backport from mainline
Index: doc/invoke.texi
===================================================================
--- doc/invoke.texi	(revision 234867)
+++ doc/invoke.texi	(working copy)
@@ -2118,6 +2118,9 @@  scope.
 Version 8, which first appeared in G++ 4.9, corrects the substitution
 behavior of function types with function-cv-qualifiers.
 
+Version 9, which first appeared in G++ 5.2, corrects the alignment of
+@code{nullptr_t}.
+
 See also @option{-Wabi}.
 
 @item -fabi-compat-version=@var{n}
@@ -2619,7 +2622,15 @@  When mangling a function type with function-cv-qua
 un-qualified function type was incorrectly treated as a substitution
 candidate.
 
-This was fixed in @option{-fabi-version=8}.
+This was fixed in @option{-fabi-version=8}, the default for GCC 5.1.
+
+@item
+@code{decltype(nullptr)} incorrectly had an alignment of 1, leading to
+unaligned accesses.  Note that this did not affect the ABI of a
+function with a @code{nullptr_t} parameter, as parameters have a
+minimum alignment.
+
+This was fixed in @option{-fabi-version=9}, the default for GCC 5.2.
 @end itemize
 
 It also warns about psABI-related changes.  The known psABI changes at this