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Re: [rfa:symtab] SYMBOL_LOCATION_FUNCS -> SYMBOL_OPS


Ok.

elena

FYI, I've so far committed the attached. Per my other post:
http://sources.redhat.com/ml/gdb-patches/2004-01/msg00671.html
I stumbled across a really horrible hack where by the function's symbol was being used to store the function's frame-base's location expression :-(. That immediatly stops the symbol_ops being called unconditionally when available, sigh.


Andrew

2004-01-26  Andrew Cagney  <cagney@redhat.com>

	* dwarf2loc.c (dwarf_expr_frame_base): Use SYMBOL_OPS instead of
	SYMBOL_LOCATION_FUNCS
	(dwarf2_loclist_funcs, dwarf2_locexpr_funcs): Change type to
	"struct symbol_ops".
	* dwarf2loc.h (dwarf2_locexpr_funcs, dwarf2_loclist_funcs): Change
	type to "struct symbol_ops".
	* symtab.h (struct symbol_ops): Rename "struct location_funcs".
	(struct symbol): Replace ".aux_value.loc.funcs" and
	".aux_value.loc.baton" with ".ops" and ".aux_value.ptr".
	(SYMBOL_OBJFILE): Delete macro.
	(SYMBOL_LOCATION_FUNCS): Delete macro.
	(SYMBOL_LOCATION_BATON): Update.
	* dwarf2read.c (dwarf2_symbol_mark_computed): Set SYMBOL_OPS
	intead of SYMBOL_LOCATION_FUNCS.
	* ax-gdb.c (gen_var_ref): Ditto.
	* printcmd.c (address_info): Ditto.
	* findvar.c (read_var_value): Ditto.
	(symbol_read_needs_frame): Ditto.

Index: ax-gdb.c
===================================================================
RCS file: /cvs/src/src/gdb/ax-gdb.c,v
retrieving revision 1.23
diff -u -r1.23 ax-gdb.c
--- ax-gdb.c	21 Jan 2004 15:37:11 -0000	1.23
+++ ax-gdb.c	26 Jan 2004 20:28:14 -0000
@@ -620,7 +620,12 @@
 
     case LOC_COMPUTED:
     case LOC_COMPUTED_ARG:
-      (*SYMBOL_LOCATION_FUNCS (var)->tracepoint_var_ref) (var, ax, value);
+      /* FIXME: cagney/2004-01-26: It should be possible to
+	 unconditionally call the SYMBOL_OPS method when available.
+	 Unfortunatly DWARF 2 stores the frame-base (instead of the
+	 function) location in a function's symbol.  Oops!  For the
+	 moment enable this when/where applicable.  */
+      SYMBOL_OPS (var)->tracepoint_var_ref (var, ax, value);
       break;
 
     case LOC_OPTIMIZED_OUT:
Index: dwarf2loc.c
===================================================================
RCS file: /cvs/src/src/gdb/dwarf2loc.c,v
retrieving revision 1.13
diff -u -r1.13 dwarf2loc.c
--- dwarf2loc.c	11 Sep 2003 15:02:51 -0000	1.13
+++ dwarf2loc.c	26 Jan 2004 20:28:14 -0000
@@ -154,7 +154,7 @@
 
   framefunc = get_frame_function (debaton->frame);
 
-  if (SYMBOL_LOCATION_FUNCS (framefunc) == &dwarf2_loclist_funcs)
+  if (SYMBOL_OPS (framefunc) == &dwarf2_loclist_funcs)
     {
       struct dwarf2_loclist_baton *symbaton;
       symbaton = SYMBOL_LOCATION_BATON (framefunc);
@@ -465,7 +465,7 @@
 
 /* The set of location functions used with the DWARF-2 expression
    evaluator.  */
-struct location_funcs dwarf2_locexpr_funcs = {
+const struct symbol_ops dwarf2_locexpr_funcs = {
   locexpr_read_variable,
   locexpr_read_needs_frame,
   locexpr_describe_location,
@@ -537,7 +537,7 @@
 
 /* The set of location functions used with the DWARF-2 expression
    evaluator and location lists.  */
-struct location_funcs dwarf2_loclist_funcs = {
+const struct symbol_ops dwarf2_loclist_funcs = {
   loclist_read_variable,
   loclist_read_needs_frame,
   loclist_describe_location,
Index: dwarf2loc.h
===================================================================
RCS file: /cvs/src/src/gdb/dwarf2loc.h,v
retrieving revision 1.3
diff -u -r1.3 dwarf2loc.h
--- dwarf2loc.h	22 Jul 2003 15:41:59 -0000	1.3
+++ dwarf2loc.h	26 Jan 2004 20:28:14 -0000
@@ -21,6 +21,8 @@
 #if !defined (DWARF2LOC_H)
 #define DWARF2LOC_H
 
+struct symbol_ops;
+
 /* This header is private to the DWARF-2 reader.  It is shared between
    dwarf2read.c and dwarf2loc.c.  */
 
@@ -62,7 +64,7 @@
   struct objfile *objfile;
 };
 
-extern struct location_funcs dwarf2_locexpr_funcs;
-extern struct location_funcs dwarf2_loclist_funcs;
+extern const struct symbol_ops dwarf2_locexpr_funcs;
+extern const struct symbol_ops dwarf2_loclist_funcs;
 
 #endif
Index: dwarf2read.c
===================================================================
RCS file: /cvs/src/src/gdb/dwarf2read.c,v
retrieving revision 1.125
diff -u -r1.125 dwarf2read.c
--- dwarf2read.c	26 Jan 2004 19:55:45 -0000	1.125
+++ dwarf2read.c	26 Jan 2004 20:28:16 -0000
@@ -7974,7 +7974,7 @@
 	complaint (&symfile_complaints,
 		   "Location list used without specifying the CU base address.");
 
-      SYMBOL_LOCATION_FUNCS (sym) = &dwarf2_loclist_funcs;
+      SYMBOL_OPS (sym) = &dwarf2_loclist_funcs;
       SYMBOL_LOCATION_BATON (sym) = baton;
     }
   else
@@ -8003,7 +8003,7 @@
 	  baton->data = NULL;
 	}
       
-      SYMBOL_LOCATION_FUNCS (sym) = &dwarf2_locexpr_funcs;
+      SYMBOL_OPS (sym) = &dwarf2_locexpr_funcs;
       SYMBOL_LOCATION_BATON (sym) = baton;
     }
 }
Index: findvar.c
===================================================================
RCS file: /cvs/src/src/gdb/findvar.c,v
retrieving revision 1.67
diff -u -r1.67 findvar.c
--- findvar.c	2 Oct 2003 20:28:29 -0000	1.67
+++ findvar.c	26 Jan 2004 20:28:17 -0000
@@ -346,11 +346,12 @@
          we failed to consider one.  */
     case LOC_COMPUTED:
     case LOC_COMPUTED_ARG:
-      {
-	struct location_funcs *symfuncs = SYMBOL_LOCATION_FUNCS (sym);
-	return (symfuncs->read_needs_frame) (sym);
-      }
-      break;
+      /* FIXME: cagney/2004-01-26: It should be possible to
+	 unconditionally call the SYMBOL_OPS method when available.
+	 Unfortunatly DWARF 2 stores the frame-base (instead of the
+	 function) location in a function's symbol.  Oops!  For the
+	 moment enable this when/where applicable.  */
+      return SYMBOL_OPS (sym)->read_needs_frame (sym);
 
     case LOC_REGISTER:
     case LOC_ARG:
@@ -564,15 +565,14 @@
 
     case LOC_COMPUTED:
     case LOC_COMPUTED_ARG:
-      {
-	struct location_funcs *funcs = SYMBOL_LOCATION_FUNCS (var);
-
-	if (frame == 0 && (funcs->read_needs_frame) (var))
-	  return 0;
-	return (funcs->read_variable) (var, frame);
-
-      }
-      break;
+      /* FIXME: cagney/2004-01-26: It should be possible to
+	 unconditionally call the SYMBOL_OPS method when available.
+	 Unfortunatly DWARF 2 stores the frame-base (instead of the
+	 function) location in a function's symbol.  Oops!  For the
+	 moment enable this when/where applicable.  */
+      if (frame == 0 && SYMBOL_OPS (var)->read_needs_frame (var))
+	return 0;
+      return SYMBOL_OPS (var)->read_variable (var, frame);
 
     case LOC_UNRESOLVED:
       {
Index: printcmd.c
===================================================================
RCS file: /cvs/src/src/gdb/printcmd.c,v
retrieving revision 1.70
diff -u -r1.70 printcmd.c
--- printcmd.c	23 Jan 2004 23:25:16 -0000	1.70
+++ printcmd.c	26 Jan 2004 20:28:17 -0000
@@ -1141,7 +1141,12 @@
 
     case LOC_COMPUTED:
     case LOC_COMPUTED_ARG:
-      (SYMBOL_LOCATION_FUNCS (sym)->describe_location) (sym, gdb_stdout);
+      /* FIXME: cagney/2004-01-26: It should be possible to
+	 unconditionally call the SYMBOL_OPS method when available.
+	 Unfortunatly DWARF 2 stores the frame-base (instead of the
+	 function) location in a function's symbol.  Oops!  For the
+	 moment enable this when/where applicable.  */
+      SYMBOL_OPS (sym)->describe_location (sym, gdb_stdout);
       break;
 
     case LOC_REGISTER:
Index: symtab.h
===================================================================
RCS file: /cvs/src/src/gdb/symtab.h,v
retrieving revision 1.84
diff -u -r1.84 symtab.h
--- symtab.h	23 Jan 2004 23:03:30 -0000	1.84
+++ symtab.h	26 Jan 2004 20:28:18 -0000
@@ -546,21 +546,12 @@
   LOC_COMPUTED_ARG
 };
 
-/* A structure of function pointers describing the location of a
-   variable, structure member, or structure base class.
+/* The methods needed to implement a symbol class.  These methods can
+   use the symbol's .aux_value for additional per-symbol information.
 
-   These functions' BATON arguments are generic data pointers, holding
-   whatever data the functions need --- the code which provides this
-   structure also provides the actual contents of the baton, and
-   decides its form.  However, there may be other rules about where
-   the baton data must be allocated; whoever is pointing to this
-   `struct location_funcs' object will know the rules.  For example,
-   when a symbol S's location is LOC_COMPUTED, then
-   SYMBOL_LOCATION_FUNCS(S) is pointing to a location_funcs structure,
-   and SYMBOL_LOCATION_BATON(S) is the baton, which must be allocated
-   on the same obstack as the symbol itself.  */
+   At present this is only used to implement location expressions.  */
 
-struct location_funcs
+struct symbol_ops
 {
 
   /* Return the value of the variable SYMBOL, relative to the stack
@@ -608,6 +599,12 @@
   ENUM_BITFIELD(domain_enum_tag) domain : 6;
 
   /* Address class */
+  /* NOTE: cagney/2003-11-02: The fields "aclass" and "ops" contain
+     overlapping information.  By creating a per-aclass ops vector, or
+     using the aclass as an index into an ops table, the aclass and
+     ops fields can be merged.  The latter, for instance, would shave
+     32-bits from each symbol (relative to a symbol lookup, any table
+     index overhead would be in the noise).  */
 
   ENUM_BITFIELD(address_class) aclass : 6;
 
@@ -617,28 +614,30 @@
 
   unsigned short line;
 
-  /* Some symbols require an additional value to be recorded on a per-
-     symbol basis.  Stash those values here. */
+  /* Method's for symbol's of this class.  */
+  /* NOTE: cagney/2003-11-02: See comment above attached to "aclass".  */
+
+  const struct symbol_ops *ops;
+
+  /* Some symbols require additional information to be recorded on a
+     per- symbol basis.  Stash those values here. */
 
   union
   {
     /* Used by LOC_BASEREG and LOC_BASEREG_ARG.  */
     short basereg;
-
-    /* For a LOC_COMPUTED or LOC_COMPUTED_ARG symbol, this is the
-       baton and location_funcs structure to find its location.  For a
-       LOC_BLOCK symbol for a function in a compilation unit compiled
-       with DWARF 2 information, this is information used internally
-       by the DWARF 2 code --- specifically, the location expression
-       for the frame base for this function.  */
+    /* An arbitrary data pointer.  Note that this data must be
+       allocated using the same obstack as the symbol itself.  */
+    /* So far it is only used by LOC_COMPUTED and LOC_COMPUTED_ARG to
+       find the location location information.  For a LOC_BLOCK symbol
+       for a function in a compilation unit compiled with DWARF 2
+       information, this is information used internally by the DWARF 2
+       code --- specifically, the location expression for the frame
+       base for this function.  */
     /* FIXME drow/2003-02-21: For the LOC_BLOCK case, it might be better
        to add a magic symbol to the block containing this information,
        or to have a generic debug info annotation slot for symbols.  */
-    struct
-    {
-      void *baton;
-      struct location_funcs *funcs;
-    } loc;
+    void *ptr;
   }
   aux_value;
 
@@ -652,8 +651,8 @@
 #define SYMBOL_LINE(symbol)		(symbol)->line
 #define SYMBOL_BASEREG(symbol)		(symbol)->aux_value.basereg
 #define SYMBOL_OBJFILE(symbol)          (symbol)->aux_value.objfile
-#define SYMBOL_LOCATION_BATON(symbol)   (symbol)->aux_value.loc.baton
-#define SYMBOL_LOCATION_FUNCS(symbol)   (symbol)->aux_value.loc.funcs
+#define SYMBOL_OPS(symbol)              (symbol)->ops
+#define SYMBOL_LOCATION_BATON(symbol)   (symbol)->aux_value.ptr
 
 /* A partial_symbol records the name, domain, and address class of
    symbols whose types we have not parsed yet.  For functions, it also

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