PATCH: Darwin mach-o stub/non-lazy-ptr fixes

["turly o'connor" <turly at apple dot com>]

Hello,

This patch fixes a number of Darwin-specific mach-o stub and
non-lazy-ptr codegen issues.

    * darwin.c (machopic_classify_ident): Handle "stale" section-
    encoded name problem to avoid generating illegal stubs.
    (func_name_maybe_scoped): Remove, not needed for gcc3.
    (machopic_indirect_call_target): Don't use it.
    (darwin_encode_section_info): Call only one of update_stubs()
    or update_non_lazy_ptrs() as DECL cannot be both.
    (machopic_output_possible_stub_label): New.
    * darwin.h (ASM_DECLARE_FUNCTION_NAME): Use it.
    * darwin-protos.h (machopic_output_possible_stub_label): Declare.

Index: darwin-protos.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/darwin-protos.h,v
retrieving revision 1.7
diff -c -3 -p -r1.7 darwin-protos.h
*** darwin-protos.h     2001/10/23 22:39:06     1.7
--- darwin-protos.h     2001/12/18 20:14:21
*************** extern void darwin_encode_section_info P
*** 64,69 ****
--- 64,71 ----
  
  extern void machopic_finish PARAMS ((FILE *));
  
+ extern void machopic_output_possible_stub_label PARAMS ((FILE *, const
char*));
+ 
  extern void darwin_exception_section PARAMS ((void));
  extern void darwin_eh_frame_section PARAMS ((void));
  
Index: darwin.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/darwin.c,v
retrieving revision 1.15
diff -c -3 -p -r1.15 darwin.c
*** darwin.c    2001/11/09 07:14:16     1.15
--- darwin.c    2001/12/18 20:14:21
*************** machopic_classify_ident (ident)
*** 118,123 ****
--- 118,139 ----
    else if (name[1] == 'T')
      return MACHOPIC_DEFINED_FUNCTION;
  
+   /* It is possible that someone is holding a "stale" name, which has
+      since been defined.  See if there is a "defined" name (i.e,
+      different from NAME only in having a '!D_' or a '!T_' instead of
+      a '!d_' or '!t_' prefix) in the identifier hash tables.  If so, say
+      that this identifier is defined.  */
+   else if (name[1] == 'd' || name[1] == 't')
+     {
+       char *new_name;
+       new_name = (char *)alloca (strlen (name) + 1);
+       strcpy (new_name, name);
+       new_name[1] = (name[1] == 'd') ? 'D' : 'T';
+       if (maybe_get_identifier (new_name) != NULL)
+       return  (name[1] == 'd') ? MACHOPIC_DEFINED_DATA
+                                : MACHOPIC_DEFINED_FUNCTION;
+     }
+ 
    for (temp = machopic_defined_list; temp != NULL_TREE; temp = TREE_CHAIN
(temp))
      {
        if (ident == TREE_VALUE (temp))
*************** machopic_indirect_data_reference (orig,
*** 527,604 ****
    return ptr_ref;
  }
  
- /* For MACHOPIC_INDIRECT_CALL_TARGET below, we need to beware of:
- 
-       extern "C" { int f(); }
-       struct X { int f(); int g(); };
-       int X::f() { ::f(); }
-       int X::g() { ::f(); f();}
- 
-   This is hairy.  Both calls to "::f()" need to be indirect (i.e., to
-   appropriate symbol stubs), but since MACHOPIC_NAME_DEFINED_P calls
-   GET_IDENTIFIER which treats "f" as "X::f", and "X::f" is indeed (being)
-   defined somewhere in "X"'s inheritance hierarchy,
MACHOPIC_NAME_DEFINED_P
-   returns TRUE when called with "f", which means that
-   MACHOPIC_INDIRECT_CALL_TARGET uses an "internal" call instead of an
-   indirect one as it should.
- 
-   Our quick-n-dirty solution to this is to call the following
-   FUNC_NAME_MAYBE_SCOPED routine which (only for C++) checks whether
-   FNAME -- the name of the function which we're calling -- is NOT a
-   mangled C++ name, AND if the current function being compiled is a
-   method, and if so, use an "external" or "indirect" call.
- 
-   Note that this function will be called ONLY when
MACHOPIC_INDIRECT_TARGET_P
-   has already indicated that the target is NOT indirect.
- 
-   This conservative solution will sometimes make indirect calls where
-   it might have been possible to make direct ones.
- 
-   FUNC_NAME_MAYBE_SCOPED returns 1 to indicate a "C" name (not scoped),
-   which in turns means we should create a stub for an indirect call.
-   */
- 
- static int is_cplusplus = -1;
- 
- static int
- func_name_maybe_scoped (fname)
-      const char *fname;
- {
- 
-   if (is_cplusplus < 0)
-     is_cplusplus = (strcmp (lang_hooks.name, "GNU C++") == 0);
- 
-   if (is_cplusplus)
-     {
-       /* If we have a method, then check whether the function we're trying
to
-          call is a "C" function.  If so, we should use an indirect call.
- 
-          It turns out to be hard to tell whether "we have a method", since
-          static member functions have a TREE_CODE of FUNCTION_TYPE, as do
-          namespace-level non-member functions.  So here, we always look
for
-          an extern-"C"-like name, and make stubs for them no matter the
-          calling context.  This is temporary, and leaves nagging suspicion
-        that improvements should be possible here.  (I.e., I suspect that
-          it can still sometimes make stubs where it needn't.)  */
- 
-       /* if (1 || TREE_CODE (TREE_TYPE (current_function_decl)) ==
METHOD_TYPE) */
-       {
-         /* If fname is of the form "f__1X" or "f__Fv", it's C++.  */
-         while (*fname == '_') ++fname;        /* skip leading underscores
*/
-         while (*fname != 0)
-           {
-             if (fname[0] == '_' && fname[1] == '_'
-                 && (fname[2] == 'F' || ISDIGIT (fname[2])))
-               return 0;
-             ++fname;
-           }
-         /* Not a C++ mangled name: must be "C", in which case play safe.
*/
-         return 1;
-       }
-     }
-   return 0;
- }
- 
  /* Transform TARGET (a MEM), which is a function call target, to the
     corresponding symbol_stub if necessary.  Return a new MEM.  */
  
--- 543,548 ----
*************** machopic_indirect_call_target (target)
*** 613,620 ****
      { 
        enum machine_mode mode = GET_MODE (XEXP (target, 0));
        const char *name = XSTR (XEXP (target, 0), 0);
  
!       if (!machopic_name_defined_p (name) || func_name_maybe_scoped
(name)) 
        {
          const char *stub_name = machopic_stub_name (name);
  
--- 557,568 ----
      { 
        enum machine_mode mode = GET_MODE (XEXP (target, 0));
        const char *name = XSTR (XEXP (target, 0), 0);
+ 
+       /* If the name is already defined, we need do nothing.  */
+       if (name[0] == '!' && name[1] == 'T')
+       return target;
  
!       if (!machopic_name_defined_p (name))
        {
          const char *stub_name = machopic_stub_name (name);
  
*************** machopic_finish (asm_out_file)
*** 894,899 ****
--- 842,851 ----
        if (! TREE_USED (temp))
        continue;
  
+       /* If the symbol is actually defined, we don't need a stub.  */
+       if (sym_name[0] == '!' && sym_name[1] == 'T')
+       continue;
+ 
        STRIP_NAME_ENCODING (sym_name, sym_name);
  
        sym = alloca (strlen (sym_name) + 2);
*************** darwin_encode_section_info (decl)
*** 1056,1063 ****
      }
    /* The non-lazy pointer list may have captured references to the
       old encoded name, change them.  */
!   update_non_lazy_ptrs (XSTR (sym_ref, 0));
!   update_stubs (XSTR (sym_ref, 0));
  }
  
  /* Scan the list of non-lazy pointers and update any recorded names whose
--- 1008,1017 ----
      }
    /* The non-lazy pointer list may have captured references to the
       old encoded name, change them.  */
!   if (TREE_CODE (decl) == VAR_DECL)
!     update_non_lazy_ptrs (XSTR (sym_ref, 0));
!   else
!     update_stubs (XSTR (sym_ref, 0));
  }
  
  /* Scan the list of non-lazy pointers and update any recorded names whose
*************** update_non_lazy_ptrs (name)
*** 1090,1095 ****
--- 1044,1080 ----
      }
  }
  
+ /* Function NAME is being defined, and its label has just been output.
+    If there's already a reference to a stub for this function, we can
+    just emit the stub label now and we don't bother emitting the stub
later. */
+ 
+ void
+ machopic_output_possible_stub_label (file, name)
+      FILE *file;
+      const char *name;
+ {
+   tree temp;
+ 
+ 
+   /* Ensure we're looking at a section-encoded name.  */
+   if (name[0] != '!' || (name[1] != 't' && name[1] != 'T'))
+     return;
+ 
+   for (temp = machopic_stubs;
+        temp != NULL_TREE;
+        temp = TREE_CHAIN (temp))
+     {
+       const char *sym_name;
+ 
+       sym_name = IDENTIFIER_POINTER (TREE_VALUE (temp));
+       if (sym_name[0] == '!' && sym_name[1] == 'T'
+         && ! strcmp (name+2, sym_name+2))
+       {
+         ASM_OUTPUT_LABEL (file, IDENTIFIER_POINTER (TREE_PURPOSE (temp)));
+         break;
+       }
+     }
+ }
  
  /* Scan the list of stubs and update any recorded names whose
     stripped name matches the argument.  */
Index: darwin.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/darwin.h,v
retrieving revision 1.21
diff -c -3 -p -r1.21 darwin.h
*** darwin.h    2001/12/17 15:05:24     1.21
--- darwin.h    2001/12/18 20:14:21
*************** do { text_section ();
\
*** 232,237 ****
--- 232,240 ----
          || DECL_INITIAL (DECL))                                         \
        ENCODE_SECTION_INFO (DECL);                                     \
      ASM_OUTPUT_LABEL (FILE, xname);                                     \
+     /* Avoid generating stubs for functions we've just defined by   \
+        outputting any required stub name label now.  */             \
+     machopic_output_possible_stub_label (FILE, xname);              \
    } while (0)
  
  /* Wrap new method names in quotes so the assembler doesn't gag.