PR26806, Suspected linker bug with LTO
Alan Modra
amodra@gmail.com
Sun Nov 1 23:14:14 GMT 2020
This patch reverts most of git commit 1e3b96fd6cf, so IR symbols are
again not marked def_regular or ref_regular. That should be enough to
stop IR symbols from becoming dynamic. To mark as-needed shared
libraries referenced by IR symbols, use the referencing BFD rather
than the ref flags.
bfd/
PR 15146
PR 26314
PR 26530
PR 26806
* elflink.c (elf_link_add_object_symbols): Don't set def/ref flags
for plugin syms. Do allow plugin syms to mark as-needed libs.
ld/
PR 26806
* testsuite/ld-plugin/lto-19.h,
* testsuite/ld-plugin/lto-19a.c,
* testsuite/ld-plugin/lto-19b.c,
* testsuite/ld-plugin/lto-19c.c: New test.
* testsuite/ld-plugin/pr26806.c,
* testsuite/ld-plugin/pr26806.d: New test.
* testsuite/ld-plugin/lto.exp: Run them.
diff --git a/bfd/elflink.c b/bfd/elflink.c
index e23d189b98..4b035a2cd5 100644
--- a/bfd/elflink.c
+++ b/bfd/elflink.c
@@ -4989,7 +4989,10 @@ elf_link_add_object_symbols (bfd *abfd, struct bfd_link_info *info)
object and a shared object. */
bfd_boolean dynsym = FALSE;
- if (! dynamic)
+ /* Plugin symbols aren't normal. Don't set def/ref flags. */
+ if ((abfd->flags & BFD_PLUGIN) != 0)
+ ;
+ else if (!dynamic)
{
if (! definition)
{
@@ -5006,14 +5009,6 @@ elf_link_add_object_symbols (bfd *abfd, struct bfd_link_info *info)
h->ref_dynamic = 1;
}
}
-
- /* If the indirect symbol has been forced local, don't
- make the real symbol dynamic. */
- if ((h == hi || !hi->forced_local)
- && (bfd_link_dll (info)
- || h->def_dynamic
- || h->ref_dynamic))
- dynsym = TRUE;
}
else
{
@@ -5027,14 +5022,25 @@ elf_link_add_object_symbols (bfd *abfd, struct bfd_link_info *info)
h->def_dynamic = 1;
hi->def_dynamic = 1;
}
+ }
- /* If the indirect symbol has been forced local, don't
- make the real symbol dynamic. */
- if ((h == hi || !hi->forced_local)
- && (h->def_regular
- || h->ref_regular
- || (h->is_weakalias
- && weakdef (h)->dynindx != -1)))
+ /* If an indirect symbol has been forced local, don't
+ make the real symbol dynamic. */
+ if (h != hi && hi->forced_local)
+ ;
+ else if (!dynamic)
+ {
+ if (bfd_link_dll (info)
+ || h->def_dynamic
+ || h->ref_dynamic)
+ dynsym = TRUE;
+ }
+ else
+ {
+ if (h->def_regular
+ || h->ref_regular
+ || (h->is_weakalias
+ && weakdef (h)->dynindx != -1))
dynsym = TRUE;
}
@@ -5170,6 +5176,10 @@ elf_link_add_object_symbols (bfd *abfd, struct bfd_link_info *info)
&& !bfd_link_relocatable (info))
dynsym = FALSE;
+ /* Nor should we make plugin symbols dynamic. */
+ if ((abfd->flags & BFD_PLUGIN) != 0)
+ dynsym = FALSE;
+
if (definition)
{
h->target_internal = isym->st_target_internal;
@@ -5196,7 +5206,7 @@ elf_link_add_object_symbols (bfd *abfd, struct bfd_link_info *info)
}
}
- if (dynsym && (abfd->flags & BFD_PLUGIN) == 0 && h->dynindx == -1)
+ if (dynsym && h->dynindx == -1)
{
if (! bfd_elf_link_record_dynamic_symbol (info, h))
goto error_free_vers;
@@ -5225,6 +5235,9 @@ elf_link_add_object_symbols (bfd *abfd, struct bfd_link_info *info)
&& definition
&& ((dynsym
&& h->ref_regular_nonweak)
+ || (old_bfd != NULL
+ && (old_bfd->flags & BFD_PLUGIN) != 0
+ && bind != STB_WEAK)
|| (h->ref_dynamic_nonweak
&& (elf_dyn_lib_class (abfd) & DYN_AS_NEEDED) != 0
&& !on_needed_list (elf_dt_name (abfd),
diff --git a/ld/testsuite/ld-plugin/lto-19.h b/ld/testsuite/ld-plugin/lto-19.h
new file mode 100644
index 0000000000..0ca48d1f1a
--- /dev/null
+++ b/ld/testsuite/ld-plugin/lto-19.h
@@ -0,0 +1,6 @@
+struct re_dfa_t {
+ const int *sb_char;
+};
+struct re_dfa_t *xregcomp (void);
+struct re_dfa_t *rpl_regcomp (void);
+void rpl_regfree (struct re_dfa_t *);
diff --git a/ld/testsuite/ld-plugin/lto-19a.c b/ld/testsuite/ld-plugin/lto-19a.c
new file mode 100644
index 0000000000..6213f79144
--- /dev/null
+++ b/ld/testsuite/ld-plugin/lto-19a.c
@@ -0,0 +1,19 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include "lto-19.h"
+
+static const int utf8_sb_map[4] = { 0x12, 0x34, 0x56, 0x78 };
+
+struct re_dfa_t *
+rpl_regcomp ()
+{
+ struct re_dfa_t *dfa = malloc (sizeof (struct re_dfa_t));
+ dfa->sb_char = utf8_sb_map;
+ return dfa;
+}
+
+void
+rpl_regfree (struct re_dfa_t *dfa)
+{
+ puts (dfa->sb_char == utf8_sb_map ? "PASS" : "FAIL");
+}
diff --git a/ld/testsuite/ld-plugin/lto-19b.c b/ld/testsuite/ld-plugin/lto-19b.c
new file mode 100644
index 0000000000..b784f84ce0
--- /dev/null
+++ b/ld/testsuite/ld-plugin/lto-19b.c
@@ -0,0 +1,7 @@
+#include "lto-19.h"
+
+struct re_dfa_t *
+xregcomp (void)
+{
+ return rpl_regcomp ();
+}
diff --git a/ld/testsuite/ld-plugin/lto-19c.c b/ld/testsuite/ld-plugin/lto-19c.c
new file mode 100644
index 0000000000..0d231ba572
--- /dev/null
+++ b/ld/testsuite/ld-plugin/lto-19c.c
@@ -0,0 +1,9 @@
+#include "lto-19.h"
+
+int
+main ()
+{
+ struct re_dfa_t *dfa = xregcomp ();
+ rpl_regfree (dfa);
+ return 0;
+}
diff --git a/ld/testsuite/ld-plugin/lto.exp b/ld/testsuite/ld-plugin/lto.exp
index 9f9f2d13ce..23c948cc64 100644
--- a/ld/testsuite/ld-plugin/lto.exp
+++ b/ld/testsuite/ld-plugin/lto.exp
@@ -403,6 +403,18 @@ set lto_link_elf_tests [list \
[list {lto-18d.o} \
{} {-flto -O2} \
{lto-18d.c} {} {}] \
+ [list {liblto-19.a} \
+ "$plug_opt" {-flto -O2 -fPIC} \
+ {lto-19a.c} {} {liblto-19.a}] \
+ [list {compile lto-19b.c} \
+ "$plug_opt" {-flto -O2 -fPIC} \
+ {lto-19b.c} {} {} {c}] \
+ [list {liblto-19.so} \
+ {-shared tmpdir/lto-19b.o tmpdir/liblto-19.a} {-O2 -fPIC} \
+ {dummy.c} {} {liblto-19.so}] \
+ [list {pr26806.so} \
+ {-shared} {-fpic -O2 -flto} \
+ {pr26806.c} {{nm {-D} pr26806.d}} {pr26806.so}] \
]
# PR 14918 checks that libgcc is not spuriously included in a shared link of
@@ -584,6 +596,10 @@ set lto_run_elf_shared_tests [list \
{-static -flto -fuse-linker-plugin} {} \
{lto-18a.c} {lto-18-4.exe} {lto-18.out} {-flto -O2} {c} {} \
{ -Ltmpdir -llto-18b -llto-18c tmpdir/lto-18d.o}] \
+ [list {lto-19} \
+ {-Wl,--as-needed,-R,tmpdir} {} \
+ {lto-19c.c} {lto-19.exe} {pass.out} {-flto -O2} {c} {} \
+ {tmpdir/liblto-19.so tmpdir/liblto-19.a}] \
]
# LTO run-time tests for ELF
diff --git a/ld/testsuite/ld-plugin/pr26806.c b/ld/testsuite/ld-plugin/pr26806.c
new file mode 100644
index 0000000000..8bb29316f5
--- /dev/null
+++ b/ld/testsuite/ld-plugin/pr26806.c
@@ -0,0 +1,2 @@
+#include <unistd.h>
+int foo (int x) { if (__builtin_constant_p (x)) return getpid (); return 0; }
diff --git a/ld/testsuite/ld-plugin/pr26806.d b/ld/testsuite/ld-plugin/pr26806.d
new file mode 100644
index 0000000000..16fa828e13
--- /dev/null
+++ b/ld/testsuite/ld-plugin/pr26806.d
@@ -0,0 +1,4 @@
+#failif
+#...
+.* _*getpid[@ ].*
+#...
--
Alan Modra
Australia Development Lab, IBM
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