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| author | Joseph Myers <joseph@codesourcery.com> | 2018-02-15 20:58:16 +0000 |
|---|---|---|
| committer | Joseph Myers <joseph@codesourcery.com> | 2018-02-15 20:58:16 +0000 |
| commit | 499b315324519f8deb5b42a143a76319934a3ab0 (patch) | |
| tree | 4923f289669b62c9093e6820341706235f96cafe | |
| parent | 7fc03cf320f9ed0178babbb33de0550d393b8886 (diff) | |
| download | glibc-499b315324519f8deb5b42a143a76319934a3ab0.zip glibc-499b315324519f8deb5b42a143a76319934a3ab0.tar.gz glibc-499b315324519f8deb5b42a143a76319934a3ab0.tar.bz2 | |
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.
| -rw-r--r-- | ChangeLog | 5 | ||||
| -rw-r--r-- | include/stdio.h | 4 | ||||
| -rw-r--r-- | libio/iofputs.c | 1 |
3 files changed, 10 insertions, 0 deletions
@@ -1,6 +1,11 @@ 2018-02-15 Joseph Myers <joseph@codesourcery.com> [BZ #15105] + * include/stdio.h [!_ISOMAC && IS_IN (libc)] (fputs): Use + libc_hidden_proto. + * libio/iofputs.c (fputs): Use libc_hidden_weak. + + [BZ #15105] [BZ #19463] * libio/feof_u.c (feof_unlocked): Rename to __feof_unlocked and define as weak alias of __feof_unlocked. Use libc_hidden_weak. diff --git a/include/stdio.h b/include/stdio.h index 7ab3ddd..7871000 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) diff --git a/libio/iofputs.c b/libio/iofputs.c index b4fbeb5..176e9ed 100644 --- a/libio/iofputs.c +++ b/libio/iofputs.c @@ -43,6 +43,7 @@ _IO_fputs (const char *str, _IO_FILE *fp) libc_hidden_def (_IO_fputs) weak_alias (_IO_fputs, fputs) +libc_hidden_weak (fputs) # ifndef _IO_MTSAFE_IO strong_alias (_IO_fputs, __fputs_unlocked) |