From f418bc3cd173bc4e679469928d4d96ffcc05fc7e Mon Sep 17 00:00:00 2001 From: Eric Botcazou Date: Tue, 4 May 2021 12:40:42 +0200 Subject: [PATCH] Fix libiberty link failures in LTO mode for MinGW The test for the presence of variables (really symbols) does not work when you add -Ox -flto to CFLAGS: for v in $vars; do AC_MSG_CHECKING([for $v]) AC_CACHE_VAL(libiberty_cv_var_$v, [AC_LINK_IFELSE([AC_LANG_PROGRAM([[int *p;]],[[extern int $v []; p = $v;]])], [eval "libiberty_cv_var_$v=yes"], [eval "libiberty_cv_var_$v=no"])]) if eval "test \"`echo '$libiberty_cv_var_'$v`\" = yes"; then AC_MSG_RESULT(yes) AC_DEFINE_UNQUOTED($n) else AC_MSG_RESULT(no) fi done because the assignment to 'p' is optimized away by LTO. This is visible on MinGW platforms in the form of a link failure for sys_siglist. There is another link failures for stpcpy: the symbol is both referenced by libiberty's pex-win32.c and provided by libiberty's stpcpy.c, so it needs to have a linkage to be resolved in LTO mode. libiberty/ * configure.ac: Make test for variables more robust. * configure: Regenerate. gcc/ * builtins.c (builtin_with_linkage_p): Return true for stp[n]cpy. * symtab.c (symtab_node::output_to_lto_symbol_table_p): Tidy up. --- gcc/builtins.c | 12 ++++++++++-- gcc/symtab.c | 5 +---- libiberty/configure | 4 ++-- libiberty/configure.ac | 2 +- 4 files changed, 14 insertions(+), 9 deletions(-) diff --git a/gcc/builtins.c b/gcc/builtins.c index 14cfa57..0db4090 100644 --- a/gcc/builtins.c +++ b/gcc/builtins.c @@ -14480,8 +14480,8 @@ target_char_cst_p (tree t, char *p) } /* Return true if the builtin DECL is implemented in a standard library. - Otherwise returns false which doesn't guarantee it is not (thus the list of - handled builtins below may be incomplete). */ + Otherwise return false which doesn't guarantee it is not (thus the list + of handled builtins below may be incomplete). */ bool builtin_with_linkage_p (tree decl) @@ -14560,6 +14560,14 @@ builtin_with_linkage_p (tree decl) CASE_FLT_FN (BUILT_IN_TRUNC): CASE_FLT_FN_FLOATN_NX (BUILT_IN_TRUNC): return true; + + case BUILT_IN_STPCPY: + case BUILT_IN_STPNCPY: + /* stpcpy is both referenced in libiberty's pex-win32.c and provided + by libiberty's stpcpy.c for MinGW targets so we need to return true + in order to be able to build libiberty in LTO mode for them. */ + return true; + default: break; } diff --git a/gcc/symtab.c b/gcc/symtab.c index 2135b34..8c4cb70 100644 --- a/gcc/symtab.c +++ b/gcc/symtab.c @@ -2526,10 +2526,7 @@ symtab_node::output_to_lto_symbol_table_p (void) in libraries so make sure to output references into the symbol table to make those libraries referenced. Note this is incomplete handling for now and only covers math functions. */ - if (builtin_with_linkage_p (decl)) - return true; - else - return false; + return builtin_with_linkage_p (decl); } /* We have real symbol that should be in symbol table. However try to trim diff --git a/libiberty/configure b/libiberty/configure index fc0c953..57498d8 100755 --- a/libiberty/configure +++ b/libiberty/configure @@ -7049,11 +7049,11 @@ else fi cat confdefs.h - <<_ACEOF >conftest.$ac_ext /* end confdefs.h. */ -int *p; +extern int $v []; int main () { -extern int $v []; p = $v; +if ($v [0]) return 1; ; return 0; } diff --git a/libiberty/configure.ac b/libiberty/configure.ac index ad95296..3c03f24 100644 --- a/libiberty/configure.ac +++ b/libiberty/configure.ac @@ -665,7 +665,7 @@ if test -z "${setobjs}"; then for v in $vars; do AC_MSG_CHECKING([for $v]) AC_CACHE_VAL(libiberty_cv_var_$v, - [AC_LINK_IFELSE([AC_LANG_PROGRAM([[int *p;]],[[extern int $v []; p = $v;]])], + [AC_LINK_IFELSE([AC_LANG_PROGRAM([[extern int $v [];]],[[if ($v [0]) return 1;]])], [eval "libiberty_cv_var_$v=yes"], [eval "libiberty_cv_var_$v=no"])]) if eval "test \"`echo '$libiberty_cv_var_'$v`\" = yes"; then -- 2.7.4