[pushed] Darwin, Objective-C : Adjust objective-c symbol linkage with version.

[Iain Sandoe]

Hi

Earlier linkers cannot handle publicly-visible (or linker-visible)
metadata, so we need to make the output of these conditional on version.

tested across the Darwin range, and on x86_64-linux
pushed to master
thanks
Iain

gcc/ChangeLog:

	* config/darwin.c (darwin_globalize_label): Make a subset of
	metadate symbols global.
	(darwin_label_is_anonymous_local_objc_name): Make a subset of
	metadata symbols linker-visible.
	(darwin_override_options): Track more target OS versions, make
	the next_runtime version track this (unless it's set to 0 for
	GNU runtime).

gcc/objc/ChangeLog:

	* objc-next-runtime-abi-02.c (FIXUP_NEEDED): Rename ...
	(USE_FIXUP_BEFORE): ... to this.
	(next_runtime_02_initialize): Likewise.
	(next_runtime_abi_02_get_arg_type_list_base): Likewise.
	(next_runtime_abi_02_build_objc_method_call): Likewise.
---
 gcc/config/darwin.c                 | 33 ++++++++++++++++++++++++++---
 gcc/objc/objc-next-runtime-abi-02.c |  8 +++----
 2 files changed, 34 insertions(+), 7 deletions(-)

diff --git a/gcc/config/darwin.c b/gcc/config/darwin.c
index 33c6ce42c1b..dd4857f9e34 100644
--- a/gcc/config/darwin.c
+++ b/gcc/config/darwin.c
@@ -1876,7 +1876,10 @@ darwin_globalize_label (FILE *stream, const char *name)
 {
   if (!!strncmp (name, "_OBJC_", 6))
     default_globalize_label (stream, name);
-  /* We have some Objective C cases that need to be global.  */
+  /* We have some Objective C cases that need to be global, but only on newer
+     OS versions.  */
+  if (flag_objc_abi < 2 || flag_next_runtime < 100700)
+    return;
   if (!strncmp (name+6, "LabelPro", 8))
     default_globalize_label (stream, name);
   if (!strncmp (name+6, "Protocol_", 9))
@@ -1901,8 +1904,14 @@ darwin_label_is_anonymous_local_objc_name (const char *name)
   }
   if (strncmp ((const char *)p, "_OBJC_", 6) != 0)
     return false;
+
   /* We need some of the objective c meta-data symbols to be visible to the
-     linker.  FIXME: this is horrible, we need a better mechanism.  */
+     linker (when the target OS version is newer).  FIXME: this is horrible,
+     we need a better mechanism.  */
+
+  if (flag_objc_abi < 2 || flag_next_runtime < 100700)
+    return true;
+
   p += 6;
   if (!strncmp ((const char *)p, "ClassRef", 8))
     return false;
@@ -3183,10 +3192,14 @@ darwin_override_options (void)
   /* Keep track of which (major) version we're generating code for.  */
   if (darwin_macosx_version_min)
     {
-      if (strverscmp (darwin_macosx_version_min, "10.6") >= 0)
+      if (strverscmp (darwin_macosx_version_min, "10.7") >= 0)
+	generating_for_darwin_version = 11;
+      else if (strverscmp (darwin_macosx_version_min, "10.6") >= 0)
 	generating_for_darwin_version = 10;
       else if (strverscmp (darwin_macosx_version_min, "10.5") >= 0)
 	generating_for_darwin_version = 9;
+      else if (strverscmp (darwin_macosx_version_min, "10.4") >= 0)
+	generating_for_darwin_version = 8;
 
       /* Earlier versions are not specifically accounted, until required.  */
     }
@@ -3202,6 +3215,20 @@ darwin_override_options (void)
      should check for correctness re. the ABI.  TODO: check and provide the
      flags (runtime & ABI) from the lto wrapper).  */
 
+  /* At present, make a hard update to the runtime version based on the target
+     OS version.  */
+  if (flag_next_runtime)
+    {
+      if (generating_for_darwin_version > 10)
+	flag_next_runtime = 100705;
+      else if (generating_for_darwin_version > 9)
+	flag_next_runtime = 100608;
+      else if (generating_for_darwin_version > 8)
+	flag_next_runtime = 100508;
+      else
+	flag_next_runtime = 100000;
+    }
+
   /* Unless set, force ABI=2 for NeXT and m64, 0 otherwise.  */
   if (!global_options_set.x_flag_objc_abi)
     global_options.x_flag_objc_abi
diff --git a/gcc/objc/objc-next-runtime-abi-02.c b/gcc/objc/objc-next-runtime-abi-02.c
index 0c7a600c597..60bf86ab8c9 100644
--- a/gcc/objc/objc-next-runtime-abi-02.c
+++ b/gcc/objc/objc-next-runtime-abi-02.c
@@ -69,7 +69,7 @@ along with GCC; see the file COPYING3.  If not see
 #define TAG_MSGSENDID_STRET	"objc_msgSendId_stret"
 #define TAG_MSGSENDSUPER_STRET	"objc_msgSendSuper2_stret"
 
-#define FIXUP_NEEDED		100600
+#define USE_FIXUP_BEFORE	100600
 #define TAG_FIXUP		"_fixup"
 
 
@@ -392,7 +392,7 @@ static void next_runtime_02_initialize (void)
   build_v2_protocol_template ();
   build_v2_category_template ();
 
-  bool fixup_p = flag_next_runtime < FIXUP_NEEDED;
+  bool fixup_p = flag_next_runtime < USE_FIXUP_BEFORE;
   if (fixup_p)
     {
       /* id objc_msgSend_fixup_rtp (id, struct message_ref_t*, ...); */
@@ -1151,7 +1151,7 @@ next_runtime_abi_02_get_arg_type_list_base (vec<tree, va_gc> **argtypes,
     receiver_type = objc_object_type;
 
   vec_safe_push (*argtypes, receiver_type);
-  if (flag_next_runtime < FIXUP_NEEDED)
+  if (flag_next_runtime < USE_FIXUP_BEFORE)
     /* Selector type - will eventually change to `int'.  */
     vec_safe_push (*argtypes, superflag ? objc_v2_super_selector_type
 					: objc_v2_selector_type);
@@ -1821,7 +1821,7 @@ next_runtime_abi_02_build_objc_method_call (location_t loc,
 	  && TREE_TYPE (receiver) == objc_class_type))
     check_for_nil = false;
 
-  if (flag_next_runtime >= FIXUP_NEEDED)
+  if (flag_next_runtime >= USE_FIXUP_BEFORE)
     {
       tree selector
 	= next_runtime_abi_02_build_selector_reference (loc, sel_name,
-- 
2.24.1