[gcc(refs/users/aoliva/heads/testme)] libstdc++-v3: no -latomic on vxworks

[Alexandre Oliva via Gcc-cvs]

https://gcc.gnu.org/g:094d994ebc2b5d7b8672ce96c375ea00bd7ae361

commit 094d994ebc2b5d7b8672ce96c375ea00bd7ae361
Author: Alexandre Oliva <ol...@adacore.com>
Date:   Thu May 8 02:18:38 2025 -0300

    libstdc++-v3: no -latomic on vxworks
    
    libatomic is disabled on vxworks because it's part of libc, and not
    very granular there, so a separately-built libatomic often triggers
    link errors over duplicate definitions.
    
    So, don't link with -latomic, but keep atomic tests enabled.
    
    Unfortunately, some fence and flag primitives that are declared as
    functions and then defined as macros are not defined as functions in
    libc, so the tests for non-macro calls fail.  Expect those failures.
    
    
    for  gcc/testsuite/ChangeLog
    
            * gcc.dg/atomic/stdatomic-fence-2.c: Xfail on vxworks.
            * gcc.dg/atomic/stdatomic-flag-2.c: Likewise.
            * lib/atomic-dg.exp (atomic_init): Don't add -latomic on
            vxworks.

Diff:
---
 gcc/testsuite/gcc.dg/atomic/stdatomic-fence-2.c | 1 +
 gcc/testsuite/gcc.dg/atomic/stdatomic-flag-2.c  | 1 +
 gcc/testsuite/lib/atomic-dg.exp                 | 6 +++++-
 3 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/gcc/testsuite/gcc.dg/atomic/stdatomic-fence-2.c 
b/gcc/testsuite/gcc.dg/atomic/stdatomic-fence-2.c
index 6916e89576c3..44d3c33dd50b 100644
--- a/gcc/testsuite/gcc.dg/atomic/stdatomic-fence-2.c
+++ b/gcc/testsuite/gcc.dg/atomic/stdatomic-fence-2.c
@@ -1,6 +1,7 @@
 /* Test atomic_*_fence routines for existence and execution with each
    valid memory model.  Out-of-line function calls.  */
 /* { dg-do run } */
+/* { dg-do-if compile { target *-*-vxworks* } } */
 /* { dg-options "-std=c11 -pedantic-errors" } */
 
 #include <stdatomic.h>
diff --git a/gcc/testsuite/gcc.dg/atomic/stdatomic-flag-2.c 
b/gcc/testsuite/gcc.dg/atomic/stdatomic-flag-2.c
index e4e3a6ef33d7..b74a54e95918 100644
--- a/gcc/testsuite/gcc.dg/atomic/stdatomic-flag-2.c
+++ b/gcc/testsuite/gcc.dg/atomic/stdatomic-flag-2.c
@@ -2,6 +2,7 @@
    function calls.  */
 /* The test needs a lockless atomic implementation.  */
 /* { dg-do run } */
+/* { dg-do-if compile { target *-*-vxworks* } } */
 /* { dg-options "-std=c11 -pedantic-errors" } */
 
 #include <stdatomic.h>
diff --git a/gcc/testsuite/lib/atomic-dg.exp b/gcc/testsuite/lib/atomic-dg.exp
index 83b225a4d3cc..b47282c50587 100644
--- a/gcc/testsuite/lib/atomic-dg.exp
+++ b/gcc/testsuite/lib/atomic-dg.exp
@@ -71,7 +71,11 @@ proc atomic_init { args } {
        }
     }
 
-    append link_flags " -latomic "
+    if { [istarget *-*-vxworks*] } {
+       # vxworks provides libatomic as part of libc.
+    } else {
+       append link_flags " -latomic "
+    }
 
     if [info exists TEST_ALWAYS_FLAGS] {
        set atomic_saved_TEST_ALWAYS_FLAGS $TEST_ALWAYS_FLAGS