https://gcc.gnu.org/g:027491d79b2749afb57aa5c8284ed69e6b1c44b5
commit r15-9228-g027491d79b2749afb57aa5c8284ed69e6b1c44b5
Author: Sandra Loosemore <sloosem...@baylibre.com>
Date: Sun Apr 6 00:11:39 2025 +0000
Doc: Document -Wpsabi [PR81831]
Per the issue, there were a couple places in the manual where
-Wno-psabi was mentioned, but the option itself was not documented.
gcc/c-family/ChangeLog
PR c/81831
* c.opt (Wpsabi): Remove "Undocumented" modifier and add a
documentation string.
gcc/ChangeLog
PR c/81831
* doc/invoke.texi (Option Summary): Add -Wno-psabi.
(Warning Options): Document -Wpsabi separately from -Wabi.
Note it's enabled by default, not just implied by -Wabi.
Replace the detailed example for a GCC 4.4 change for x86
(which is unlikely to be very interesting nowadays) with
just a list of all targets that presently diagnose these
warnings.
(RS/6000 and PowerPC Options): Add cross-references for
-Wno-psabi.
Diff:
---
gcc/c-family/c.opt | 3 ++-
gcc/doc/invoke.texi | 51 ++++++++++++++++++++++++---------------------------
2 files changed, 26 insertions(+), 28 deletions(-)
diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt
index ad216983126e..75b6531860eb 100644
--- a/gcc/c-family/c.opt
+++ b/gcc/c-family/c.opt
@@ -303,7 +303,8 @@ C++ ObjC++ Var(warn_abi_tag) Warning
Warn if a subobject has an abi_tag attribute that the complete object type
does not have.
Wpsabi
-C ObjC C++ ObjC++ LTO Var(warn_psabi) Init(1) Warning Undocumented
LangEnabledBy(C ObjC C++ ObjC++,Wabi)
+C ObjC C++ ObjC++ LTO Var(warn_psabi) Init(1) Warning LangEnabledBy(C ObjC C++
ObjC++,Wabi)
+Warn about code affected by incompatible psABI changes.
Wabsolute-value
C ObjC Var(warn_absolute_value) Warning EnabledBy(Wextra)
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 8f51ea6d3e11..91ed43dc21a0 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -406,7 +406,9 @@ Objective-C and Objective-C++ Dialects}.
-Wparentheses -Wno-pedantic-ms-format
-Wpointer-arith -Wno-pointer-compare -Wno-pointer-to-int-cast
-Wno-pragmas -Wno-pragma-once-outside-header -Wno-prio-ctor-dtor
--Wredundant-decls -Wrestrict -Wno-return-local-addr -Wreturn-type
+-Wno-psabi
+-Wredundant-decls -Wrestrict
+-Wno-return-local-addr -Wreturn-type
-Wno-scalar-storage-order -Wsequence-point
-Wshadow -Wshadow=global -Wshadow=local -Wshadow=compatible-local
-Wno-shadow-ivar
@@ -6497,7 +6499,8 @@ of a derived class.
Warn about code affected by ABI changes. This includes code that may
not be compatible with the vendor-neutral C++ ABI as well as the psABI
-for the particular target.
+for the particular target. The latter warnings are also controlled
+separately by @option{-Wpsabi}, which is implied by @option{-Wabi}.
Since G++ now defaults to updating the ABI with each major release,
normally @option{-Wabi} warns only about C++ ABI compatibility
@@ -6600,27 +6603,21 @@ This was fixed in @option{-fabi-version=10}, the
default for GCC 6.1.
@end itemize
-This option also enables warnings about psABI-related changes.
-The known psABI changes at this point include:
+@opindex Wpsabi
+@opindex Wno-psabi
+@item -Wpsabi @r{(C, Objective-C, C++ and Objective-C++ only)}
-@itemize @bullet
-
-@item
-For SysV/x86-64, unions with @code{long double} members are
-passed in memory as specified in psABI. Prior to GCC 4.4, this was not
-the case. For example:
+@option{-Wpsabi} enables warnings about processor-specific ABI
+changes, such as changes in alignment requirements or how function
+arguments are passed. On several targets, including AArch64, ARM,
+x86, MIPS, RS6000/PowerPC, and S/390, these details have changed
+between different versions of GCC and/or different versions of the C
+or C++ language standards in ways that affect binary compatibility of
+compiled code. With @option{-Wpsabi}, GCC can detect potentially
+incompatible usages and warn you about them.
-@smallexample
-union U @{
- long double ld;
- int i;
-@};
-@end smallexample
-
-@noindent
-@code{union U} is now always passed in memory.
-
-@end itemize
+@option{-Wpsabi} is enabled by default, and is also implied by
+@option{-Wabi}.
@opindex Wchanges-meaning
@opindex Wno-changes-meaning
@@ -32452,18 +32449,18 @@ and for AIX: @samp{vec-extabi}, @samp{vec-default}@.
Change the current ABI to use IBM extended-precision long double.
This is not likely to work if your system defaults to using IEEE
extended-precision long double. If you change the long double type
-from IEEE extended-precision, the compiler will issue a warning unless
-you use the @option{-Wno-psabi} option. Requires @option{-mlong-double-128}
-to be enabled.
+from IEEE extended-precision, the compiler issues a warning unless
+you use the @option{-Wno-psabi} option (@pxref{Warning Options}).
+Requires @option{-mlong-double-128} to be enabled.
@opindex mabi=ieeelongdouble
@item -mabi=ieeelongdouble
Change the current ABI to use IEEE extended-precision long double.
This is not likely to work if your system defaults to using IBM
extended-precision long double. If you change the long double type
-from IBM extended-precision, the compiler will issue a warning unless
-you use the @option{-Wno-psabi} option. Requires @option{-mlong-double-128}
-to be enabled.
+from IBM extended-precision, the compiler issues a warning unless
+you use the @option{-Wno-psabi} option (@pxref{Warning Options}).
+Requires @option{-mlong-double-128} to be enabled.
@opindex mabi=elfv1
@item -mabi=elfv1
