Hi,
PR 78253 shows that the handling of weak references has changed for
ARM with gcc-5.
When r220674 was committed, default_binds_local_p_2 gained a new
parameter (weak_dominate), which, when true, implies that a reference
to a weak symbol defined locally will be resolved locally, even though
it could be overridden by a strong definition in another object file.
With r220674, default_binds_local_p forces weak_dominate=true,
effectively changing the previous behavior.
The attached patch introduces default_binds_local_p_4 which is a copy
of default_binds_local_p_2, but using weak_dominate=false, and updates
the ARM target to call default_binds_local_p_4 instead of
default_binds_local_p_2.
I ran cross-tests on various arm* configurations with no regression,
and checked that the test attached to the original bugzilla now works
as expected.
I am not sure why weak_dominate defaults to true, and I couldn't
really understand why by reading the threads related to r220674 and
following updates to default_binds_local_p_* which all deal with other
corner cases and do not discuss the weak_dominate parameter.
Or should this patch be made more generic?
Thanks,
Christophe
2016-11-09 Christophe Lyon <christophe.l...@linaro.org>
PR target/78253
* output.h (default_binds_local_p_4): New.
* varasm.c (default_binds_local_p_4): New, use
weak_dominate=false.
* config/arm/linux-elf.h (TARGET_BINDS_LOCAL_P): Define to
default_binds_local_p_4.
diff --git a/gcc/config/arm/linux-elf.h b/gcc/config/arm/linux-elf.h
index cc17b51..4f32ce8 100644
--- a/gcc/config/arm/linux-elf.h
+++ b/gcc/config/arm/linux-elf.h
@@ -110,7 +110,7 @@
strong definitions in dependent shared libraries, will resolve
to COPY relocated symbol in the executable. See PR65780. */
#undef TARGET_BINDS_LOCAL_P
-#define TARGET_BINDS_LOCAL_P default_binds_local_p_2
+#define TARGET_BINDS_LOCAL_P default_binds_local_p_4
/* Define this to be nonzero if static stack checking is supported. */
#define STACK_CHECK_STATIC_BUILTIN 1
diff --git a/gcc/output.h b/gcc/output.h
index 0924499..11b5ce5 100644
--- a/gcc/output.h
+++ b/gcc/output.h
@@ -585,6 +585,7 @@ extern bool default_binds_local_p (const_tree);
extern bool default_binds_local_p_1 (const_tree, int);
extern bool default_binds_local_p_2 (const_tree);
extern bool default_binds_local_p_3 (const_tree, bool, bool, bool, bool);
+extern bool default_binds_local_p_4 (const_tree);
extern void default_globalize_label (FILE *, const char *);
extern void default_globalize_decl_name (FILE *, tree);
extern void default_emit_unwind_label (FILE *, tree, int, int);
diff --git a/gcc/varasm.c b/gcc/varasm.c
index 6a7ffc2..7a3cf99 100644
--- a/gcc/varasm.c
+++ b/gcc/varasm.c
@@ -6952,6 +6952,16 @@ default_binds_local_p_2 (const_tree exp)
!flag_pic);
}
+/* Similar to default_binds_local_p_2, but local weak definition does
+ not imply local resolution (weak_dominate is false). */
+
+bool
+default_binds_local_p_4 (const_tree exp)
+{
+ return default_binds_local_p_3 (exp, flag_shlib != 0, false, true,
+ !flag_pic);
+}
+
bool
default_binds_local_p_1 (const_tree exp, int shlib)
{
