[patch/rfc] Add frame unwinder registrary

[Andrew Cagney <ac131313 at redhat dot com>]

[ref: cagney-unwind-20030108-branch]

This patch add the two files frame-unwind.[hc] that implement a simple 
frame unwind registrary.

Given a function that contains the address PC, the method 
frame_unwind_find_by_pc(ARCH,PC) returns methods that can unwind the 
specified function's stack frame.

At present the code knows about two frames:

dummy-frame
these are the frames that GDB creates when doing an inferior function call.

trad[itional]-frame
GDB's traditional / original prologe analysis, extra frame info, frame 
saved regs, frame.

Architectures can add to this list.  On the above branch, the d10v adds 
a rewritten d10v specific frame unwinder.  An obvious addition would be 
a CFI frame unwinder.

I'll look to commit this in a few days.
Andrew
2003-01-16  Andrew Cagney  <ac131313@redhat.com>

	* dummy-frame.h (dummy_frame_id_unwind): Delete declaration.
	(dummy_frame_pc_unwind, dummy_frame_register_unwind): Ditto.
	(struct frame_unwind): Declare opaque.
	(dummy_frame_p): Declare function.
	* dummy-frame.c (dummy_frame_id_unwind): Make static.
	(dummy_frame_pc_unwind, dummy_frame_register_unwind): Ditto.
	* dummy-frame.c: Include "frame-unwind.h".
	(dummy_frame_p): New function.
	(dummy_frame_unwind): New variable.
	* frame.c: Include "frame-unwind.h".
	(frame_pc_unwind, frame_id_unwind, frame_register_unwind): Update
	to use the new unwind field.
	(set_unwind_by_pc): Delete function.
	(create_new_frame, get_prev_frame): Set unwind field using
	frame_unwind_find_by_pc.
	(trad_frame_unwind, trad_frame_unwinder): New variables.
	* frame.h (trad_frame_unwind): Declare variable.
	(frame_id_unwind_ftype): Delete declaration.
	(frame_pc_unwind_ftype, frame_register_unwind_ftype): Ditto.
	(struct frame_unwind): Declare opaque.
	(struct frame_info): Replace the fields id_unwind, pc_unwind and
	register_unwind with a single unwind pointer.
	* frame-unwind.h, frame-unwind.c: New files.
	* Makefile.in (SFILES): Add frame-unwind.c.
	(frame_unwind_h): Define.
	(COMMON_OBS): Add frame-unwind.o.
	(frame-unwind.o): Specify dependencies.
	(frame.o, dummy-frame.o): Update dependencies.
	
Index: Makefile.in
===================================================================
RCS file: /cvs/src/src/gdb/Makefile.in,v
retrieving revision 1.312
diff -u -r1.312 Makefile.in
--- Makefile.in	13 Jan 2003 18:00:16 -0000	1.312
+++ Makefile.in	16 Jan 2003 19:49:55 -0000
@@ -511,6 +511,7 @@
 	dummy-frame.c dwarfread.c dwarf2read.c \
 	elfread.c environ.c eval.c event-loop.c event-top.c expprint.c \
 	f-exp.y f-lang.c f-typeprint.c f-valprint.c findvar.c frame.c \
+	frame-unwind.c \
 	gdbarch.c arch-utils.c gdbtypes.c gnu-v2-abi.c gnu-v3-abi.c \
 	hpacc-abi.c \
 	inf-loop.c infcmd.c inflow.c infrun.c \
@@ -623,6 +624,7 @@
 expression_h = expression.h $(symtab_h) $(doublest_h)
 f_lang_h = f-lang.h
 frame_h = frame.h
+frame_unwind_h = frame-unwind.h
 gdb_events_h = gdb-events.h
 gdb_stabs_h = gdb-stabs.h
 gdb_h = gdb.h
@@ -833,7 +835,7 @@
 	c-valprint.o cp-valprint.o f-valprint.o m2-valprint.o \
 	nlmread.o serial.o mdebugread.o top.o utils.o \
 	ui-file.o \
-	frame.o doublest.o \
+	frame.o frame-unwind.o doublest.o \
 	gnu-v2-abi.o gnu-v3-abi.o hpacc-abi.o cp-abi.o cp-support.o \
 	reggroups.o
 
@@ -1636,7 +1638,7 @@
 dpx2-nat.o: dpx2-nat.c $(defs_h) $(gdbcore_h) $(gdb_string_h)
 dsrec.o: dsrec.c $(defs_h) $(serial_h) $(srec_h)
 dummy-frame.o: dummy-frame.c $(defs_h) $(dummy_frame_h) $(regcache_h) \
-	$(frame_h) $(inferior_h) $(gdb_assert_h)
+	$(frame_h) $(inferior_h) $(gdb_assert_h) $(frame_unwind_h)
 dve3900-rom.o: dve3900-rom.c $(defs_h) $(gdbcore_h) $(target_h) $(monitor_h) \
 	$(serial_h) $(inferior_h) $(command_h) $(gdb_string_h) $(regcache_h)
 dwarf2cfi.o: dwarf2cfi.c $(defs_h) $(gdbcore_h) $(symtab_h) $(symfile_h) \
@@ -1688,7 +1690,9 @@
 frame.o: frame.c $(defs_h) $(frame_h) $(target_h) $(value_h) $(inferior_h) \
 	$(regcache_h) $(gdb_assert_h) $(gdb_string_h) $(builtin_regs_h) \
 	$(gdb_obstack_h) $(dummy_frame_h) $(gdbcore_h) $(annotate_h) \
-	$(language_h)
+	$(language_h) $(frame_unwind_h)
+frame-unwind.o: frame-unwind.c $(defs_h) $(frame_h) $(frame_unwind_h) \
+	$(gdb_assert_h) $(dummy_frame_h) $(legacy_frame_h)
 frv-tdep.o: frv-tdep.c $(defs_h) $(inferior_h) $(symfile_h) $(gdbcore_h) \
 	$(arch_utils_h) $(regcache_h)
 gcore.o: gcore.c $(defs_h) $(cli_decode_h) $(inferior_h) $(gdbcore_h) \
Index: dummy-frame.c
===================================================================
RCS file: /cvs/src/src/gdb/dummy-frame.c,v
retrieving revision 1.8
diff -u -r1.8 dummy-frame.c
--- dummy-frame.c	16 Jan 2003 16:54:56 -0000	1.8
+++ dummy-frame.c	16 Jan 2003 19:49:55 -0000
@@ -28,6 +28,7 @@
 #include "frame.h"
 #include "inferior.h"
 #include "gdb_assert.h"
+#include "frame-unwind.h"
 
 /* Dummy frame.  This saves the processor state just prior to setting
    up the inferior function call.  Older targets save the registers
@@ -304,7 +305,7 @@
 /* Given a call-dummy dummy-frame, return the registers.  Here the
    register value is taken from the local copy of the register buffer.  */
 
-void
+static void
 dummy_frame_register_unwind (struct frame_info *frame, void **cache,
 			     int regnum, int *optimized,
 			     enum lval_type *lvalp, CORE_ADDR *addrp,
@@ -331,7 +332,10 @@
     }
 }
 
-CORE_ADDR
+/* Assuming that FRAME is a dummy, return the resume address for the
+   previous frame.  */
+
+static CORE_ADDR
 dummy_frame_pc_unwind (struct frame_info *frame,
 		       void **cache)
 {
@@ -345,8 +349,12 @@
 }
 
 
-void
-dummy_frame_id_unwind (struct frame_info *frame, void **cache,
+/* Assuming that FRAME is a dummy, return the ID of the calling frame
+   (the frame that the dummy has the saved state of).  */
+
+static void
+dummy_frame_id_unwind (struct frame_info *frame,
+		       void **cache,
 		       struct frame_id *id)
 {
   struct dummy_frame *dummy = cached_find_dummy_frame (frame, cache);
@@ -359,3 +367,20 @@
     (*id) = dummy->id;
 }
 
+static struct frame_unwind dummy_frame_unwind =
+{
+  dummy_frame_pc_unwind,
+  dummy_frame_id_unwind,
+  dummy_frame_register_unwind
+};
+
+const struct frame_unwind *
+dummy_frame_p (CORE_ADDR pc)
+{
+  if (DEPRECATED_PC_IN_CALL_DUMMY_P ()
+      ? DEPRECATED_PC_IN_CALL_DUMMY (pc, 0, 0)
+      : pc_in_dummy_frame (pc))
+    return &dummy_frame_unwind;
+  else
+    return NULL;
+}
Index: dummy-frame.h
===================================================================
RCS file: /cvs/src/src/gdb/dummy-frame.h,v
retrieving revision 1.6
diff -u -r1.6 dummy-frame.h
--- dummy-frame.h	16 Jan 2003 16:54:56 -0000	1.6
+++ dummy-frame.h	16 Jan 2003 19:49:55 -0000
@@ -24,6 +24,7 @@
 
 struct frame_info;
 struct regcache;
+struct frame_unwind;
 struct frame_id;
 
 /* GENERIC DUMMY FRAMES
@@ -43,30 +44,10 @@
    generic_{file,func}_frame_chain_valid and FIX_CALL_DUMMY as
    generic_fix_call_dummy.  */
 
-/* Assuming that FRAME is a dummy, return a register value for the
-   previous frame.  */
+/* If the PC falls in a dummy frame, return a dummy frame
+   unwinder.  */
 
-extern void dummy_frame_register_unwind (struct frame_info *frame,
-					 void **unwind_cache,
-					 int regnum,
-					 int *optimized,
-					 enum lval_type *lvalp,
-					 CORE_ADDR *addrp,
-					 int *realnump,
-					 void *valuep);
-
-/* Assuming that FRAME is a dummy, return the resume address for the
-   previous frame.  */
-
-extern CORE_ADDR dummy_frame_pc_unwind (struct frame_info *frame,
-					void **unwind_cache);
-
-/* Assuming that FRAME is a dummy, return the ID of the calling frame
-   (the frame that the dummy has the saved state of).  */
-
-extern void dummy_frame_id_unwind (struct frame_info *frame,
-				   void **unwind_cache,
-				   struct frame_id *id);
+extern const struct frame_unwind *dummy_frame_p (CORE_ADDR pc);
 
 /* Does the PC fall in a dummy frame?
 
Index: frame.c
===================================================================
RCS file: /cvs/src/src/gdb/frame.c,v
retrieving revision 1.58
diff -u -r1.58 frame.c
--- frame.c	16 Jan 2003 16:54:57 -0000	1.58
+++ frame.c	16 Jan 2003 19:49:56 -0000
@@ -34,6 +34,7 @@
 #include "gdbcore.h"
 #include "annotate.h"
 #include "language.h"
+#include "frame-unwind.h"
 
 /* Return a frame uniq ID that can be used to, later, re-find the
    frame.  */
@@ -127,7 +128,7 @@
 {
   if (!frame->pc_unwind_cache_p)
     {
-      frame->pc_unwind_cache = frame->pc_unwind (frame, &frame->unwind_cache);
+      frame->pc_unwind_cache = frame->unwind->pc (frame, &frame->unwind_cache);
       frame->pc_unwind_cache_p = 1;
     }
   return frame->pc_unwind_cache;
@@ -138,7 +139,7 @@
 {
   if (!frame->id_unwind_cache_p)
     {
-      frame->id_unwind (frame, &frame->unwind_cache, &frame->id_unwind_cache);
+      frame->unwind->id (frame, &frame->unwind_cache, &frame->id_unwind_cache);
       frame->id_unwind_cache_p = 1;
     }
   return frame->id_unwind_cache;
@@ -185,8 +186,8 @@
     }
 
   /* Ask this frame to unwind its register.  */
-  frame->register_unwind (frame, &frame->unwind_cache, regnum,
-			  optimizedp, lvalp, addrp, realnump, bufferp);
+  frame->unwind->reg (frame, &frame->unwind_cache, regnum,
+		      optimizedp, lvalp, addrp, realnump, bufferp);
 }
 
 void
@@ -714,6 +715,14 @@
   id->base = base;
 }
 	
+const struct frame_unwind trad_frame_unwinder = {
+  frame_saved_regs_pc_unwind,
+  frame_saved_regs_id_unwind,
+  frame_saved_regs_register_unwind
+};
+const struct frame_unwind *trad_frame_unwind = &trad_frame_unwinder;
+
+
 /* Function: get_saved_register
    Find register number REGNUM relative to FRAME and put its (raw,
    target format) contents in *RAW_BUFFER.  
@@ -813,42 +822,6 @@
     deprecated_read_register_gen (regnum, raw_buffer);
 }
 
-/* Using the PC, select a mechanism for unwinding a frame returning
-   the previous frame.  The register unwind function should, on
-   demand, initialize the ->context object.  */
-
-static void
-set_unwind_by_pc (CORE_ADDR pc, CORE_ADDR fp,
-		  frame_register_unwind_ftype **unwind_register,
-		  frame_pc_unwind_ftype **unwind_pc,
-		  frame_id_unwind_ftype **unwind_id)
-{
-  if (!DEPRECATED_USE_GENERIC_DUMMY_FRAMES)
-    {
-      /* Still need to set this to something.  The ``info frame'' code
-	 calls this function to find out where the saved registers are.
-	 Hopefully this is robust enough to stop any core dumps and
-	 return vaguely correct values..  */
-      *unwind_register = frame_saved_regs_register_unwind;
-      *unwind_pc = frame_saved_regs_pc_unwind;
-      *unwind_id = frame_saved_regs_id_unwind;
-    }
-  else if (DEPRECATED_PC_IN_CALL_DUMMY_P ()
-	   ? DEPRECATED_PC_IN_CALL_DUMMY (pc, 0, 0)
-	   : pc_in_dummy_frame (pc))
-    {
-      *unwind_register = dummy_frame_register_unwind;
-      *unwind_pc = dummy_frame_pc_unwind;
-      *unwind_id = dummy_frame_id_unwind;
-    }
-  else
-    {
-      *unwind_register = frame_saved_regs_register_unwind;
-      *unwind_pc = frame_saved_regs_pc_unwind;
-      *unwind_id = frame_saved_regs_id_unwind;
-    }
-}
-
 /* Create an arbitrary (i.e. address specified by user) or innermost frame.
    Always returns a non-NULL value.  */
 
@@ -891,8 +864,7 @@
     INIT_EXTRA_FRAME_INFO (0, fi);
 
   /* Select/initialize an unwind function.  */
-  set_unwind_by_pc (fi->pc, fi->frame, &fi->register_unwind,
-		    &fi->pc_unwind, &fi->id_unwind);
+  fi->unwind = frame_unwind_find_by_pc (current_gdbarch, fi->pc);
 
   return fi;
 }
@@ -1135,8 +1107,7 @@
      (and probably other architectural information).  The PC lets you
      check things like the debug info at that point (dwarf2cfi?) and
      use that to decide how the frame should be unwound.  */
-  set_unwind_by_pc (prev->pc, prev->frame, &prev->register_unwind,
-		    &prev->pc_unwind, &prev->id_unwind);
+  prev->unwind = frame_unwind_find_by_pc (current_gdbarch, prev->pc);
 
   /* NOTE: cagney/2002-11-18: The code segments, found in
      create_new_frame and get_prev_frame(), that initializes the
Index: frame.h
===================================================================
RCS file: /cvs/src/src/gdb/frame.h,v
retrieving revision 1.61
diff -u -r1.61 frame.h
--- frame.h	16 Jan 2003 16:54:57 -0000	1.61
+++ frame.h	16 Jan 2003 19:49:56 -0000
@@ -24,6 +24,10 @@
 #define FRAME_H 1
 
 struct symtab_and_line;
+struct frame_unwind;
+
+/* The traditional frame unwinder.  */
+extern const struct frame_unwind *trad_frame_unwind;
 
 /* The frame object.  */
 
@@ -302,43 +306,6 @@
    caller's frame.  */
 extern struct frame_id frame_id_unwind (struct frame_info *frame);
 
-
-/* Return the location (and possibly value) of REGNUM for the previous
-   (older, up) frame.  All parameters except VALUEP can be assumed to
-   be non NULL.  When VALUEP is NULL, just the location of the
-   register should be returned.
-
-   UNWIND_CACHE is provided as mechanism for implementing a per-frame
-   local cache.  It's initial value being NULL.  Memory for that cache
-   should be allocated using frame_obstack_zalloc().
-
-   Register window architectures (eg SPARC) should note that REGNUM
-   identifies the register for the previous frame.  For instance, a
-   request for the value of "o1" for the previous frame would be found
-   in the register "i1" in this FRAME.  */
-
-typedef void (frame_register_unwind_ftype) (struct frame_info *frame,
-					    void **unwind_cache,
-					    int regnum,
-					    int *optimized,
-					    enum lval_type *lvalp,
-					    CORE_ADDR *addrp,
-					    int *realnump,
-					    void *valuep);
-
-/* Same as for registers above, but return the address at which the
-   calling frame would resume.  */
-
-typedef CORE_ADDR (frame_pc_unwind_ftype) (struct frame_info *frame,
-					   void **unwind_cache);
-
-/* Same as for registers above, but return the ID of the frame that
-   called this one.  */
-
-typedef void (frame_id_unwind_ftype) (struct frame_info *frame,
-				      void **unwind_cache,
-				      struct frame_id *id);
-
 /* Describe the saved registers of a frame.  */
 
 #if defined (EXTRA_FRAME_INFO) || defined (FRAME_FIND_SAVED_REGS)
@@ -426,18 +393,14 @@
        better all agree as to the contents.  */
     void *unwind_cache;
 
-    /* See description above.  The previous frame's registers.  */
-    frame_register_unwind_ftype *register_unwind;
+    /* The frame's unwinder.  */
+    const struct frame_unwind *unwind;
 
-    /* See description above.  The previous frame's resume address.
-       Save the previous PC in a local cache.  */
-    frame_pc_unwind_ftype *pc_unwind;
+    /* Cached copy of the previous frame's resume address.  */
     int pc_unwind_cache_p;
     CORE_ADDR pc_unwind_cache;
 
-    /* See description above.  The previous frame's resume address.
-       Save the previous PC in a local cache.  */
-    frame_id_unwind_ftype *id_unwind;
+    /* Cached copy of the previous frame's ID.  */
     int id_unwind_cache_p;
     struct frame_id id_unwind_cache;