Hi Steven,
On 5 Jun 2012, at 21:23, Steven Bosscher wrote:
> On Tue, Jun 5, 2012 at 8:55 PM, Iain Sandoe <i...@codesourcery.com> wrote:
>> I would welcome a simple solution if one is available, although I don't
>> quite see what you have in mind at present.
>
> This is what I have in mind. Untested, but it shows the idea. What do
> you think of this?
Thanks, it looks like a good compromise given the small number of targets using
it.
Just for the record, the NeXT ObjC runtime is open sourced, and could be ported
to a non-Darwin target (as long as it has named sections) - I do recall Nicola
made the comment that it would be harder for targets other than x86/PPC since
there is some asm in the message forwarding scheme.
===
As for your patch, I've moved stuff around a bit and fixed up a couple of typos
(notes below), but retained your scheme (hopefully as you intended).
The attached patch survives normal and lto bootstrap on i686-darwin9 and
x86_64-darwin10.
No regressions for ObjC or Obj-C++.
Otherwise, lightly tested, but appears to solve PR 48109 on the way.
changes:
o [minor] typo fixes and some changes to the comments, minor adjustments to
make the asm indents match with other code.
o I moved the functions to config/darwin-c.c (I suspect that's what you
originally intended, from the comments).
o I made two (c-family) target hooks instead of generating new target macros -
side benefits of this are:
(i) that we can also remove tm.h from objc-next-runtime-abi-01.c
(ii) we don't end up with dead code pathways on non-darwin builds.
(iii) the actual implementation of the defs/refs is now private to Darwin.
if you think this good to go - given that Mike has already commented, then I
guess we should move it to Patches for review.
thanks for the idea!
Iain
Index: gcc/doc/tm.texi
===================================================================
--- gcc/doc/tm.texi (revision 188216)
+++ gcc/doc/tm.texi (working copy)
@@ -694,6 +694,14 @@ should use @code{TARGET_HANDLE_C_OPTION} instead.
Targets may provide a string object type that can be used within and between
C, C++ and their respective Objective-C dialects. A string object might, for
example, embed encoding and length information. These objects are considered
opaque to the compiler and handled as references. An ideal implementation makes
the composition of the string object match that of the Objective-C
@code{NSString} (@code{NXString} for GNUStep), allowing efficient interworking
between C-only and Objective-C code. If a target implements string objects then
this hook should return a reference to such an object constructed from the
normal `C' string representation provided in @var{string}. At present, the hook
is used by Objective-C only, to obtain a common-format string object when the
target provides one.
@end deftypefn
+@deftypefn {C Target Hook} void TARGET_OBJC_DECLARE_UNRESOLVED_CLASS_REFERENCE
(const char *@var{classname})
+Declare that Objective C class @var{classname} is referenced by the current
TU.
+@end deftypefn
+
+@deftypefn {C Target Hook} void TARGET_OBJC_DECLARE_CLASS_DEFINITION (const
char *@var{classname})
+Declare that Objective C class @var{classname} is defined by the current TU.
+@end deftypefn
+
@deftypefn {C Target Hook} bool TARGET_STRING_OBJECT_REF_TYPE_P (const_tree
@var{stringref})
If a target implements string objects then this hook should return @code{true}
if @var{stringref} is a valid reference to such an object.
@end deftypefn
Index: gcc/c-family/c-target.def
===================================================================
--- gcc/c-family/c-target.def (revision 188216)
+++ gcc/c-family/c-target.def (working copy)
@@ -59,8 +59,22 @@ DEFHOOK
common-format string object when the target provides one.",
tree, (tree string),
NULL)
-
+
DEFHOOK
+(objc_declare_unresolved_class_reference,
+ "Declare that Objective C class @var{classname} is referenced\
+ by the current TU.",
+ void, (const char *classname),
+ NULL)
+
+DEFHOOK
+(objc_declare_class_definition,
+ "Declare that Objective C class @var{classname} is defined\
+ by the current TU.",
+ void, (const char *classname),
+ NULL)
+
+DEFHOOK
(string_object_ref_type_p,
"If a target implements string objects then this hook should return\
@code{true} if @var{stringref} is a valid reference to such an object.",
Index: gcc/objc/objc-next-runtime-abi-01.c
===================================================================
--- gcc/objc/objc-next-runtime-abi-01.c (revision 188216)
+++ gcc/objc/objc-next-runtime-abi-01.c (working copy)
@@ -26,7 +26,6 @@ along with GCC; see the file COPYING3. If not see
#include "config.h"
#include "system.h"
#include "coretypes.h"
-#include "tm.h"
#include "tree.h"
#ifdef OBJCPLUS
@@ -49,7 +48,7 @@ along with GCC; see the file COPYING3. If not see
#include "ggc.h"
#include "target.h"
-#include "output.h" /* for asm_out_file */
+#include "c-family/c-target.h"
#include "tree-iterator.h"
#include "objc-runtime-hooks.h"
@@ -2267,47 +2266,50 @@ generate_objc_symtab_decl (void)
init_objc_symtab (TREE_TYPE (UOBJC_SYMBOLS_decl)));
}
+/* Any target implementing NeXT ObjC m32 ABI has to ensure that objects
+ refer to, and define, symbols that enforce linkage of classes into the
+ executable image, preserving unix archive semantics.
+ At present (4.8), the only targets implementing this are Darwin; these
+ use top level asms to implement a scheme (see config/darwin-c.c). The
+ latter method is a hack, but compatible with LTO see also PR48109 for
+ further discussion and other possible methods. */
+
static void
-handle_next_class_ref (tree chain)
+handle_next_class_ref (tree chain ATTRIBUTE_UNUSED)
{
- const char *name = IDENTIFIER_POINTER (TREE_VALUE (chain));
- char *string = (char *) alloca (strlen (name) + 30);
-
- sprintf (string, ".objc_class_name_%s", name);
-
-#ifdef ASM_DECLARE_UNRESOLVED_REFERENCE
- ASM_DECLARE_UNRESOLVED_REFERENCE (asm_out_file, string);
-#else
- return ; /* NULL build for targets other than Darwin. */
-#endif
+ if (targetcm.objc_declare_unresolved_class_reference)
+ {
+ const char *name = IDENTIFIER_POINTER (TREE_VALUE (chain));
+ char *string = (char *) alloca (strlen (name) + 30);
+ sprintf (string, ".objc_class_name_%s", name);
+ targetcm.objc_declare_unresolved_class_reference (string);
+ }
}
static void
-handle_next_impent (struct imp_entry *impent)
+handle_next_impent (struct imp_entry *impent ATTRIBUTE_UNUSED)
{
- char buf[BUFSIZE];
+ if (targetcm.objc_declare_class_definition)
+ {
+ char buf[BUFSIZE];
- switch (TREE_CODE (impent->imp_context))
- {
- case CLASS_IMPLEMENTATION_TYPE:
- snprintf (buf, BUFSIZE, ".objc_class_name_%s",
- IDENTIFIER_POINTER (CLASS_NAME (impent->imp_context)));
- break;
- case CATEGORY_IMPLEMENTATION_TYPE:
- snprintf (buf, BUFSIZE, "*.objc_category_name_%s_%s",
- IDENTIFIER_POINTER (CLASS_NAME (impent->imp_context)),
- IDENTIFIER_POINTER (CLASS_SUPER_NAME (impent->imp_context)));
- break;
- default:
- return;
+ switch (TREE_CODE (impent->imp_context))
+ {
+ case CLASS_IMPLEMENTATION_TYPE:
+ snprintf (buf, BUFSIZE, ".objc_class_name_%s",
+ IDENTIFIER_POINTER (CLASS_NAME (impent->imp_context)));
+ break;
+ case CATEGORY_IMPLEMENTATION_TYPE:
+ snprintf (buf, BUFSIZE, "*.objc_category_name_%s_%s",
+ IDENTIFIER_POINTER (CLASS_NAME (impent->imp_context)),
+ IDENTIFIER_POINTER (CLASS_SUPER_NAME
(impent->imp_context)));
+ break;
+ default:
+ return;
+ }
+ targetcm.objc_declare_class_definition (buf);
}
-
-#ifdef ASM_DECLARE_CLASS_REFERENCE
- ASM_DECLARE_CLASS_REFERENCE (asm_out_file, buf);
-#else
- return ; /* NULL build for targets other than Darwin. */
-#endif
}
static void
@@ -2414,9 +2416,7 @@ objc_generate_v1_next_metadata (void)
/* Dump the class references. This forces the appropriate classes
to be linked into the executable image, preserving unix archive
- semantics. This can be removed when we move to a more dynamically
- linked environment. */
-
+ semantics. */
for (chain = cls_ref_chain; chain; chain = TREE_CHAIN (chain))
{
handle_next_class_ref (chain);
Index: gcc/config/darwin-c.c
===================================================================
--- gcc/config/darwin-c.c (revision 188216)
+++ gcc/config/darwin-c.c (working copy)
@@ -25,6 +25,7 @@ along with GCC; see the file COPYING3. If not see
#include "tm.h"
#include "cpplib.h"
#include "tree.h"
+#include "target.h"
#include "incpath.h"
#include "c-family/c-common.h"
#include "c-family/c-pragma.h"
@@ -36,6 +37,7 @@ along with GCC; see the file COPYING3. If not see
#include "prefix.h"
#include "c-family/c-target.h"
#include "c-family/c-target-def.h"
+#include "cgraph.h"
/* Pragmas. */
@@ -711,13 +713,60 @@ EXPORTED_CONST format_kind_info darwin_additional_
}
};
-#undef TARGET_HANDLE_C_OPTION
+
+/* Support routines to dump the class references for NeXT ABI v1, aka
+ 32-bits ObjC-2.0, as top-level asms.
+ The following two functions should only be called from
+ objc/objc-next-runtime-abi-01.c. */
+
+static void
+darwin_objc_declare_unresolved_class_reference (const char *name)
+{
+ const char *lazy_reference = ".lazy_reference\t";
+ const char *hard_reference = ".reference\t";
+ const char *reference = MACHOPIC_INDIRECT ? lazy_reference : hard_reference;
+ size_t len = strlen (reference) + strlen(name) + 2;
+ char *buf = (char *) alloca (len);
+
+ gcc_checking_assert (!strncmp (name, ".objc_class_name_", 17));
+
+ snprintf (buf, len, "%s%s", reference, name);
+ add_asm_node (build_string (strlen (buf), buf));
+}
+
+static void
+darwin_objc_declare_class_definition (const char *name)
+{
+ const char *xname = targetm.strip_name_encoding (name);
+ size_t len = strlen (xname) + 7 + 5;
+ char *buf = (char *) alloca (len);
+
+ gcc_checking_assert (!strncmp (name, ".objc_class_name_", 17)
+ || !strncmp (name, "*.objc_category_name_", 21));
+
+ /* Mimic default_globalize_label. */
+ snprintf (buf, len, ".globl\t%s", xname);
+ add_asm_node (build_string (strlen (buf), buf));
+
+ snprintf (buf, len, "%s = 0", xname);
+ add_asm_node (build_string (strlen (buf), buf));
+}
+
+#undef TARGET_HANDLE_C_OPTION
#define TARGET_HANDLE_C_OPTION handle_c_option
-#undef TARGET_OBJC_CONSTRUCT_STRING_OBJECT
+#undef TARGET_OBJC_CONSTRUCT_STRING_OBJECT
#define TARGET_OBJC_CONSTRUCT_STRING_OBJECT darwin_objc_construct_string
-#undef TARGET_STRING_OBJECT_REF_TYPE_P
+#undef TARGET_OBJC_DECLARE_UNRESOLVED_CLASS_REFERENCE
+#define TARGET_OBJC_DECLARE_UNRESOLVED_CLASS_REFERENCE \
+ darwin_objc_declare_unresolved_class_reference
+
+#undef TARGET_OBJC_DECLARE_CLASS_DEFINITION
+#define TARGET_OBJC_DECLARE_CLASS_DEFINITION \
+ darwin_objc_declare_class_definition
+
+#undef TARGET_STRING_OBJECT_REF_TYPE_P
#define TARGET_STRING_OBJECT_REF_TYPE_P darwin_cfstring_ref_p
#undef TARGET_CHECK_STRING_OBJECT_FORMAT_ARG
Index: gcc/config/darwin.h
===================================================================
--- gcc/config/darwin.h (revision 188216)
+++ gcc/config/darwin.h (working copy)
@@ -616,8 +613,6 @@ int darwin_label_is_anonymous_local_objc_name (con
fprintf (FILE, "\"%s\"", xname); \
else if (darwin_label_is_anonymous_local_objc_name (xname)) \
fprintf (FILE, "L%s", xname); \
- else if (!strncmp (xname, ".objc_class_name_", 17)) \
- fprintf (FILE, "%s", xname); \
else if (xname[0] != '"' && name_needs_quotes (xname)) \
asm_fprintf (FILE, "\"%U%s\"", xname); \
else \
@@ -700,29 +695,6 @@ extern GTY(()) section * darwin_sections[NUM_DARWI
#undef TARGET_ASM_RELOC_RW_MASK
#define TARGET_ASM_RELOC_RW_MASK machopic_reloc_rw_mask
-
-#define ASM_DECLARE_UNRESOLVED_REFERENCE(FILE,NAME) \
- do { \
- if (FILE) { \
- if (MACHOPIC_INDIRECT) \
- fprintf (FILE, "\t.lazy_reference "); \
- else \
- fprintf (FILE, "\t.reference "); \
- assemble_name (FILE, NAME); \
- fprintf (FILE, "\n"); \
- } \
- } while (0)
-
-#define ASM_DECLARE_CLASS_REFERENCE(FILE,NAME) \
- do { \
- if (FILE) { \
- fprintf (FILE, "\t"); \
- assemble_name (FILE, NAME); \
- fprintf (FILE, "=0\n"); \
- (*targetm.asm_out.globalize_label) (FILE, NAME); \
- } \
- } while (0)
-
/* Globalizing directive for a label. */
#define GLOBAL_ASM_OP "\t.globl "
#define TARGET_ASM_GLOBALIZE_LABEL darwin_globalize_label
