From 499b315324519f8deb5b42a143a76319934a3ab0 Mon Sep 17 00:00:00 2001 From: Joseph Myers Date: Thu, 15 Feb 2018 20:58:16 +0000 Subject: Use libc_hidden_* for fputs (bug 15105). Among other localplt test failures when building with -Os, there are libc.so PLT references for fputs. fputs calls normally get redirected to _IO_fputs by a macro in include/stdio.h (and _IO_fputs in turn uses libc_hidden_proto), but GCC can convert an fprintf call with a constant string argument into an fputs call, which of course is then unaffected by the macro redirection. (I don't know why this issue only appears with -Os.) This patch duly adds a use of libc_hidden_proto for fputs. I see no obvious reason why the fputs macro redirection is needed at all, but this patch does not change it. Tested for x86_64 (both that it removes this particular localplt failure for -Os - but other such failures remain so the bug can't yet be closed - and that the testsuite continues to pass without -Os). [BZ #15105] * include/stdio.h [!_ISOMAC && IS_IN (libc)] (fputs): Use libc_hidden_proto. * libio/iofputs.c (fputs): Use libc_hidden_weak. --- include/stdio.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include/stdio.h') diff --git a/include/stdio.h b/include/stdio.h index 7ab3ddd942..7871000071 100644 --- a/include/stdio.h +++ b/include/stdio.h @@ -140,6 +140,10 @@ extern int _IO_new_fclose (_IO_FILE*); # define fclose(fp) _IO_new_fclose (fp) extern int _IO_fputs (const char*, _IO_FILE*); libc_hidden_proto (_IO_fputs) +/* The compiler may optimize calls to fprintf into calls to fputs. + Use libc_hidden_proto to ensure that those calls, not redirected by + the fputs macro, also do not go through the PLT. */ +libc_hidden_proto (fputs) # define fputs(str, fp) _IO_fputs (str, fp) extern int _IO_new_fsetpos (_IO_FILE *, const _IO_fpos_t *); # define fsetpos(fp, posp) _IO_new_fsetpos (fp, posp) -- cgit v1.2.3