Do not redirect calls to __GI_* symbols, when redirecting to *ieee128

On platforms where long double has IEEE binary128 format as a third
option (initially, only powerpc64le), many exported functions are
redirected to their __*ieee128 equivalents.  This redirection is
provided by installed headers such as stdio-ldbl.h, and is supposed to
work correctly with user code.

However, during the build of glibc, similar redirections are employed,
in internal headers, such as include/stdio.h, in order to avoid extra
PLT entries.  These redirections conflict with the redirections to
__*ieee128, and must be avoided during the build.  This patch protects
the second redirections with a test for __LONG_DOUBLE_USES_FLOAT128, a
new macro that is defined to 1 when functions that deal with long double
typed values reuses the _Float128 implementation (this is currently only
true for powerpc64le).

Tested for powerpc64le, x86_64, and with build-many-glibcs.py.

Co-authored-by: Gabriel F. T. Gomes <gabrielftg@linux.ibm.com>
Reviewed-by: Florian Weimer <fweimer@redhat.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/include/stdlib.h b/include/stdlib.h
index 114e12d255..1fab78aa16 100644
--- a/include/stdlib.h
+++ b/include/stdlib.h
@@ -202,9 +202,12 @@ libc_hidden_proto (____strtoll_l_internal)
 libc_hidden_proto (____strtoul_l_internal)
 libc_hidden_proto (____strtoull_l_internal)
 
+#include <bits/floatn.h>
 libc_hidden_proto (strtof)
 libc_hidden_proto (strtod)
+#if __LONG_DOUBLE_USES_FLOAT128 == 0
 libc_hidden_proto (strtold)
+#endif
 libc_hidden_proto (strtol)
 libc_hidden_proto (strtoll)
 libc_hidden_proto (strtoul)