gdb/blockframe.c - third_party/binutils-gdb - Git at Google

 /* Get info from stack frames; convert between frames, blocks,
    functions and pc values.

    Copyright 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994,
    1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002 Free Software
    Foundation, Inc.

    This file is part of GDB.

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place - Suite 330,
    Boston, MA 02111-1307, USA.  */

 #include "defs.h"
 #include "symtab.h"
 #include "bfd.h"
 #include "symfile.h"
 #include "objfiles.h"
 #include "frame.h"
 #include "gdbcore.h"
 #include "value.h"		/* for read_register */
 #include "target.h"		/* for target_has_stack */
 #include "inferior.h"		/* for read_pc */
 #include "annotate.h"
 #include "regcache.h"
 #include "gdb_assert.h"
 #include "dummy-frame.h"

 /* Prototypes for exported functions. */

 void _initialize_blockframe (void);

 /* A default FRAME_CHAIN_VALID, in the form that is suitable for most
    targets.  If FRAME_CHAIN_VALID returns zero it means that the given
    frame is the outermost one and has no caller. */

 int
 file_frame_chain_valid (CORE_ADDR chain, struct frame_info *thisframe)
 {
   return ((chain) != 0
 	  && !inside_entry_file (frame_pc_unwind (thisframe)));
 }

 /* Use the alternate method of avoiding running up off the end of the
    frame chain or following frames back into the startup code.  See
    the comments in objfiles.h. */

 int
 func_frame_chain_valid (CORE_ADDR chain, struct frame_info *thisframe)
 {
   return ((chain) != 0
 	  && !inside_main_func (get_frame_pc (thisframe))
 	  && !inside_entry_func (get_frame_pc (thisframe)));
 }

 /* A very simple method of determining a valid frame */

 int
 nonnull_frame_chain_valid (CORE_ADDR chain, struct frame_info *thisframe)
 {
   return ((chain) != 0);
 }

 /* Is ADDR inside the startup file?  Note that if your machine
    has a way to detect the bottom of the stack, there is no need
    to call this function from FRAME_CHAIN_VALID; the reason for
    doing so is that some machines have no way of detecting bottom
    of stack.

    A PC of zero is always considered to be the bottom of the stack. */

 int
 inside_entry_file (CORE_ADDR addr)
 {
   if (addr == 0)
     return 1;
   if (symfile_objfile == 0)
     return 0;
   if (CALL_DUMMY_LOCATION == AT_ENTRY_POINT)
     {
       /* Do not stop backtracing if the pc is in the call dummy
          at the entry point.  */
       /* FIXME: Won't always work with zeros for the last two arguments */
       if (DEPRECATED_PC_IN_CALL_DUMMY (addr, 0, 0))
 	return 0;
     }
   return (addr >= symfile_objfile->ei.entry_file_lowpc &&
 	  addr < symfile_objfile->ei.entry_file_highpc);
 }

 /* Test a specified PC value to see if it is in the range of addresses
    that correspond to the main() function.  See comments above for why
    we might want to do this.

    Typically called from FRAME_CHAIN_VALID.

    A PC of zero is always considered to be the bottom of the stack. */

 int
 inside_main_func (CORE_ADDR pc)
 {
   if (pc == 0)
     return 1;
   if (symfile_objfile == 0)
     return 0;

   /* If the addr range is not set up at symbol reading time, set it up now.
      This is for FRAME_CHAIN_VALID_ALTERNATE. I do this for coff, because
      it is unable to set it up and symbol reading time. */

   if (symfile_objfile->ei.main_func_lowpc == INVALID_ENTRY_LOWPC &&
       symfile_objfile->ei.main_func_highpc == INVALID_ENTRY_HIGHPC)
     {
       struct symbol *mainsym;

       mainsym = lookup_symbol (main_name (), NULL, VAR_NAMESPACE, NULL, NULL);
       if (mainsym && SYMBOL_CLASS (mainsym) == LOC_BLOCK)
 	{
 	  symfile_objfile->ei.main_func_lowpc =
 	    BLOCK_START (SYMBOL_BLOCK_VALUE (mainsym));
 	  symfile_objfile->ei.main_func_highpc =
 	    BLOCK_END (SYMBOL_BLOCK_VALUE (mainsym));
 	}
     }
   return (symfile_objfile->ei.main_func_lowpc <= pc &&
 	  symfile_objfile->ei.main_func_highpc > pc);
 }

 /* Test a specified PC value to see if it is in the range of addresses
    that correspond to the process entry point function.  See comments
    in objfiles.h for why we might want to do this.

    Typically called from FRAME_CHAIN_VALID.

    A PC of zero is always considered to be the bottom of the stack. */

 int
 inside_entry_func (CORE_ADDR pc)
 {
   if (pc == 0)
     return 1;
   if (symfile_objfile == 0)
     return 0;
   if (CALL_DUMMY_LOCATION == AT_ENTRY_POINT)
     {
       /* Do not stop backtracing if the pc is in the call dummy
          at the entry point.  */
       /* FIXME: Won't always work with zeros for the last two arguments */
       if (DEPRECATED_PC_IN_CALL_DUMMY (pc, 0, 0))
 	return 0;
     }
   return (symfile_objfile->ei.entry_func_lowpc <= pc &&
 	  symfile_objfile->ei.entry_func_highpc > pc);
 }

 /* Return nonzero if the function for this frame lacks a prologue.  Many
    machines can define FRAMELESS_FUNCTION_INVOCATION to just call this
    function.  */

 int
 frameless_look_for_prologue (struct frame_info *frame)
 {
   CORE_ADDR func_start, after_prologue;

   func_start = get_pc_function_start (get_frame_pc (frame));
   if (func_start)
     {
       func_start += FUNCTION_START_OFFSET;
       /* This is faster, since only care whether there *is* a
          prologue, not how long it is.  */
       return PROLOGUE_FRAMELESS_P (func_start);
     }
   else if (get_frame_pc (frame) == 0)
     /* A frame with a zero PC is usually created by dereferencing a
        NULL function pointer, normally causing an immediate core dump
        of the inferior. Mark function as frameless, as the inferior
        has no chance of setting up a stack frame.  */
     return 1;
   else
     /* If we can't find the start of the function, we don't really
        know whether the function is frameless, but we should be able
        to get a reasonable (i.e. best we can do under the
        circumstances) backtrace by saying that it isn't.  */
     return 0;
 }

 /* return the address of the PC for the given FRAME, ie the current PC value
    if FRAME is the innermost frame, or the address adjusted to point to the
    call instruction if not.  */

 CORE_ADDR
 frame_address_in_block (struct frame_info *frame)
 {
   CORE_ADDR pc = get_frame_pc (frame);

   /* If we are not in the innermost frame, and we are not interrupted
      by a signal, frame->pc points to the instruction following the
      call. As a consequence, we need to get the address of the previous
      instruction. Unfortunately, this is not straightforward to do, so
      we just use the address minus one, which is a good enough
      approximation.  */
   /* FIXME: cagney/2002-11-10: Should this instead test for
      NORMAL_FRAME?  A dummy frame (in fact all the abnormal frames)
      save the PC value in the block.  */
   if (get_next_frame (frame) != 0
       && get_frame_type (get_next_frame (frame)) != SIGTRAMP_FRAME)
     --pc;

   return pc;
 }

 /* Return the innermost lexical block in execution
    in a specified stack frame.  The frame address is assumed valid.

    If ADDR_IN_BLOCK is non-zero, set *ADDR_IN_BLOCK to the exact code
    address we used to choose the block.  We use this to find a source
    line, to decide which macro definitions are in scope.

    The value returned in *ADDR_IN_BLOCK isn't necessarily the frame's
    PC, and may not really be a valid PC at all.  For example, in the
    caller of a function declared to never return, the code at the
    return address will never be reached, so the call instruction may
    be the very last instruction in the block.  So the address we use
    to choose the block is actually one byte before the return address
    --- hopefully pointing us at the call instruction, or its delay
    slot instruction.  */

 struct block *
 get_frame_block (struct frame_info *frame, CORE_ADDR *addr_in_block)
 {
   const CORE_ADDR pc = frame_address_in_block (frame);

   if (addr_in_block)
     *addr_in_block = pc;

   return block_for_pc (pc);
 }

 CORE_ADDR
 get_pc_function_start (CORE_ADDR pc)
 {
   register struct block *bl;
   register struct symbol *symbol;
   register struct minimal_symbol *msymbol;
   CORE_ADDR fstart;

   if ((bl = block_for_pc (pc)) != NULL &&
       (symbol = block_function (bl)) != NULL)
     {
       bl = SYMBOL_BLOCK_VALUE (symbol);
       fstart = BLOCK_START (bl);
     }
   else if ((msymbol = lookup_minimal_symbol_by_pc (pc)) != NULL)
     {
       fstart = SYMBOL_VALUE_ADDRESS (msymbol);
       if (!find_pc_section (fstart))
 	return 0;
     }
   else
     {
       fstart = 0;
     }
   return (fstart);
 }

 /* Return the symbol for the function executing in frame FRAME.  */

 struct symbol *
 get_frame_function (struct frame_info *frame)
 {
   register struct block *bl = get_frame_block (frame, 0);
   if (bl == 0)
     return 0;
   return block_function (bl);
 }


 /* Return the blockvector immediately containing the innermost lexical block
    containing the specified pc value and section, or 0 if there is none.
    PINDEX is a pointer to the index value of the block.  If PINDEX
    is NULL, we don't pass this information back to the caller.  */

 struct blockvector *
 blockvector_for_pc_sect (register CORE_ADDR pc, struct sec *section,
 			 int *pindex, struct symtab *symtab)
 {
   register struct block *b;
   register int bot, top, half;
   struct blockvector *bl;

   if (symtab == 0)		/* if no symtab specified by caller */
     {
       /* First search all symtabs for one whose file contains our pc */
       if ((symtab = find_pc_sect_symtab (pc, section)) == 0)
 	return 0;
     }

   bl = BLOCKVECTOR (symtab);
   b = BLOCKVECTOR_BLOCK (bl, 0);

   /* Then search that symtab for the smallest block that wins.  */
   /* Use binary search to find the last block that starts before PC.  */

   bot = 0;
   top = BLOCKVECTOR_NBLOCKS (bl);

   while (top - bot > 1)
     {
       half = (top - bot + 1) >> 1;
       b = BLOCKVECTOR_BLOCK (bl, bot + half);
       if (BLOCK_START (b) <= pc)
 	bot += half;
       else
 	top = bot + half;
     }

   /* Now search backward for a block that ends after PC.  */

   while (bot >= 0)
     {
       b = BLOCKVECTOR_BLOCK (bl, bot);
       if (BLOCK_END (b) > pc)
 	{
 	  if (pindex)
 	    *pindex = bot;
 	  return bl;
 	}
       bot--;
     }
   return 0;
 }

 /* Return the blockvector immediately containing the innermost lexical block
    containing the specified pc value, or 0 if there is none.
    Backward compatibility, no section.  */

 struct blockvector *
 blockvector_for_pc (register CORE_ADDR pc, int *pindex)
 {
   return blockvector_for_pc_sect (pc, find_pc_mapped_section (pc),
 				  pindex, NULL);
 }

 /* Return the innermost lexical block containing the specified pc value
    in the specified section, or 0 if there is none.  */

 struct block *
 block_for_pc_sect (register CORE_ADDR pc, struct sec *section)
 {
   register struct blockvector *bl;
   int index;

   bl = blockvector_for_pc_sect (pc, section, &index, NULL);
   if (bl)
     return BLOCKVECTOR_BLOCK (bl, index);
   return 0;
 }

 /* Return the innermost lexical block containing the specified pc value,
    or 0 if there is none.  Backward compatibility, no section.  */

 struct block *
 block_for_pc (register CORE_ADDR pc)
 {
   return block_for_pc_sect (pc, find_pc_mapped_section (pc));
 }

 /* Return the function containing pc value PC in section SECTION.
    Returns 0 if function is not known.  */

 struct symbol *
 find_pc_sect_function (CORE_ADDR pc, struct sec *section)
 {
   register struct block *b = block_for_pc_sect (pc, section);
   if (b == 0)
     return 0;
   return block_function (b);
 }

 /* Return the function containing pc value PC.
    Returns 0 if function is not known.  Backward compatibility, no section */

 struct symbol *
 find_pc_function (CORE_ADDR pc)
 {
   return find_pc_sect_function (pc, find_pc_mapped_section (pc));
 }

 /* These variables are used to cache the most recent result
  * of find_pc_partial_function. */

 static CORE_ADDR cache_pc_function_low = 0;
 static CORE_ADDR cache_pc_function_high = 0;
 static char *cache_pc_function_name = 0;
 static struct sec *cache_pc_function_section = NULL;

 /* Clear cache, e.g. when symbol table is discarded. */

 void
 clear_pc_function_cache (void)
 {
   cache_pc_function_low = 0;
   cache_pc_function_high = 0;
   cache_pc_function_name = (char *) 0;
   cache_pc_function_section = NULL;
 }

 /* Finds the "function" (text symbol) that is smaller than PC but
    greatest of all of the potential text symbols in SECTION.  Sets
    *NAME and/or *ADDRESS conditionally if that pointer is non-null.
    If ENDADDR is non-null, then set *ENDADDR to be the end of the
    function (exclusive), but passing ENDADDR as non-null means that
    the function might cause symbols to be read.  This function either
    succeeds or fails (not halfway succeeds).  If it succeeds, it sets
    *NAME, *ADDRESS, and *ENDADDR to real information and returns 1.
    If it fails, it sets *NAME, *ADDRESS, and *ENDADDR to zero and
    returns 0.  */

 int
 find_pc_sect_partial_function (CORE_ADDR pc, asection *section, char **name,
 			       CORE_ADDR *address, CORE_ADDR *endaddr)
 {
   struct partial_symtab *pst;
   struct symbol *f;
   struct minimal_symbol *msymbol;
   struct partial_symbol *psb;
   struct obj_section *osect;
   int i;
   CORE_ADDR mapped_pc;

   mapped_pc = overlay_mapped_address (pc, section);

   if (mapped_pc >= cache_pc_function_low
       && mapped_pc < cache_pc_function_high
       && section == cache_pc_function_section)
     goto return_cached_value;

   /* If sigtramp is in the u area, it counts as a function (especially
      important for step_1).  */
   if (SIGTRAMP_START_P () && PC_IN_SIGTRAMP (mapped_pc, (char *) NULL))
     {
       cache_pc_function_low = SIGTRAMP_START (mapped_pc);
       cache_pc_function_high = SIGTRAMP_END (mapped_pc);
       cache_pc_function_name = "<sigtramp>";
       cache_pc_function_section = section;
       goto return_cached_value;
     }

   msymbol = lookup_minimal_symbol_by_pc_section (mapped_pc, section);
   pst = find_pc_sect_psymtab (mapped_pc, section);
   if (pst)
     {
       /* Need to read the symbols to get a good value for the end address.  */
       if (endaddr != NULL && !pst->readin)
 	{
 	  /* Need to get the terminal in case symbol-reading produces
 	     output.  */
 	  target_terminal_ours_for_output ();
 	  PSYMTAB_TO_SYMTAB (pst);
 	}

       if (pst->readin)
 	{
 	  /* Checking whether the msymbol has a larger value is for the
 	     "pathological" case mentioned in print_frame_info.  */
 	  f = find_pc_sect_function (mapped_pc, section);
 	  if (f != NULL
 	      && (msymbol == NULL
 		  || (BLOCK_START (SYMBOL_BLOCK_VALUE (f))
 		      >= SYMBOL_VALUE_ADDRESS (msymbol))))
 	    {
 	      cache_pc_function_low = BLOCK_START (SYMBOL_BLOCK_VALUE (f));
 	      cache_pc_function_high = BLOCK_END (SYMBOL_BLOCK_VALUE (f));
 	      cache_pc_function_name = SYMBOL_NAME (f);
 	      cache_pc_function_section = section;
 	      goto return_cached_value;
 	    }
 	}
       else
 	{
 	  /* Now that static symbols go in the minimal symbol table, perhaps
 	     we could just ignore the partial symbols.  But at least for now
 	     we use the partial or minimal symbol, whichever is larger.  */
 	  psb = find_pc_sect_psymbol (pst, mapped_pc, section);

 	  if (psb
 	      && (msymbol == NULL ||
 		  (SYMBOL_VALUE_ADDRESS (psb)
 		   >= SYMBOL_VALUE_ADDRESS (msymbol))))
 	    {
 	      /* This case isn't being cached currently. */
 	      if (address)
 		*address = SYMBOL_VALUE_ADDRESS (psb);
 	      if (name)
 		*name = SYMBOL_NAME (psb);
 	      /* endaddr non-NULL can't happen here.  */
 	      return 1;
 	    }
 	}
     }

   /* Not in the normal symbol tables, see if the pc is in a known section.
      If it's not, then give up.  This ensures that anything beyond the end
      of the text seg doesn't appear to be part of the last function in the
      text segment.  */

   osect = find_pc_sect_section (mapped_pc, section);

   if (!osect)
     msymbol = NULL;

   /* Must be in the minimal symbol table.  */
   if (msymbol == NULL)
     {
       /* No available symbol.  */
       if (name != NULL)
 	*name = 0;
       if (address != NULL)
 	*address = 0;
       if (endaddr != NULL)
 	*endaddr = 0;
       return 0;
     }

   cache_pc_function_low = SYMBOL_VALUE_ADDRESS (msymbol);
   cache_pc_function_name = SYMBOL_NAME (msymbol);
   cache_pc_function_section = section;

   /* Use the lesser of the next minimal symbol in the same section, or
      the end of the section, as the end of the function.  */

   /* Step over other symbols at this same address, and symbols in
      other sections, to find the next symbol in this section with
      a different address.  */

   for (i = 1; SYMBOL_NAME (msymbol + i) != NULL; i++)
     {
       if (SYMBOL_VALUE_ADDRESS (msymbol + i) != SYMBOL_VALUE_ADDRESS (msymbol)
 	  && SYMBOL_BFD_SECTION (msymbol + i) == SYMBOL_BFD_SECTION (msymbol))
 	break;
     }

   if (SYMBOL_NAME (msymbol + i) != NULL
       && SYMBOL_VALUE_ADDRESS (msymbol + i) < osect->endaddr)
     cache_pc_function_high = SYMBOL_VALUE_ADDRESS (msymbol + i);
   else
     /* We got the start address from the last msymbol in the objfile.
        So the end address is the end of the section.  */
     cache_pc_function_high = osect->endaddr;

  return_cached_value:

   if (address)
     {
       if (pc_in_unmapped_range (pc, section))
 	*address = overlay_unmapped_address (cache_pc_function_low, section);
       else
 	*address = cache_pc_function_low;
     }

   if (name)
     *name = cache_pc_function_name;

   if (endaddr)
     {
       if (pc_in_unmapped_range (pc, section))
 	{
 	  /* Because the high address is actually beyond the end of
 	     the function (and therefore possibly beyond the end of
 	     the overlay), we must actually convert (high - 1) and
 	     then add one to that. */

 	  *endaddr = 1 + overlay_unmapped_address (cache_pc_function_high - 1,
 						   section);
 	}
       else
 	*endaddr = cache_pc_function_high;
     }

   return 1;
 }

 /* Backward compatibility, no section argument.  */

 int
 find_pc_partial_function (CORE_ADDR pc, char **name, CORE_ADDR *address,
 			  CORE_ADDR *endaddr)
 {
   asection *section;

   section = find_pc_overlay (pc);
   return find_pc_sect_partial_function (pc, section, name, address, endaddr);
 }

 /* Return the innermost stack frame executing inside of BLOCK,
    or NULL if there is no such frame.  If BLOCK is NULL, just return NULL.  */

 struct frame_info *
 block_innermost_frame (struct block *block)
 {
   struct frame_info *frame;
   register CORE_ADDR start;
   register CORE_ADDR end;
   CORE_ADDR calling_pc;

   if (block == NULL)
     return NULL;

   start = BLOCK_START (block);
   end = BLOCK_END (block);

   frame = NULL;
   while (1)
     {
       frame = get_prev_frame (frame);
       if (frame == NULL)
 	return NULL;
       calling_pc = frame_address_in_block (frame);
       if (calling_pc >= start && calling_pc < end)
 	return frame;
     }
 }

 /* Are we in a call dummy?  The code below which allows DECR_PC_AFTER_BREAK
    below is for infrun.c, which may give the macro a pc without that
    subtracted out.  */

 extern CORE_ADDR text_end;

 int
 deprecated_pc_in_call_dummy_before_text_end (CORE_ADDR pc, CORE_ADDR sp,
 					     CORE_ADDR frame_address)
 {
   return ((pc) >= text_end - CALL_DUMMY_LENGTH
 	  && (pc) <= text_end + DECR_PC_AFTER_BREAK);
 }

 int
 deprecated_pc_in_call_dummy_after_text_end (CORE_ADDR pc, CORE_ADDR sp,
 					    CORE_ADDR frame_address)
 {
   return ((pc) >= text_end
 	  && (pc) <= text_end + CALL_DUMMY_LENGTH + DECR_PC_AFTER_BREAK);
 }

 /* Is the PC in a call dummy?  SP and FRAME_ADDRESS are the bottom and
    top of the stack frame which we are checking, where "bottom" and
    "top" refer to some section of memory which contains the code for
    the call dummy.  Calls to this macro assume that the contents of
    SP_REGNUM and FP_REGNUM (or the saved values thereof), respectively,
    are the things to pass.

    This won't work on the 29k, where SP_REGNUM and FP_REGNUM don't
    have that meaning, but the 29k doesn't use ON_STACK.  This could be
    fixed by generalizing this scheme, perhaps by passing in a frame
    and adding a few fields, at least on machines which need them for
    DEPRECATED_PC_IN_CALL_DUMMY.

    Something simpler, like checking for the stack segment, doesn't work,
    since various programs (threads implementations, gcc nested function
    stubs, etc) may either allocate stack frames in another segment, or
    allocate other kinds of code on the stack.  */

 int
 deprecated_pc_in_call_dummy_on_stack (CORE_ADDR pc, CORE_ADDR sp,
 				      CORE_ADDR frame_address)
 {
   return (INNER_THAN ((sp), (pc))
 	  && (frame_address != 0)
 	  && INNER_THAN ((pc), (frame_address)));
 }

 int
 deprecated_pc_in_call_dummy_at_entry_point (CORE_ADDR pc, CORE_ADDR sp,
 					    CORE_ADDR frame_address)
 {
   return ((pc) >= CALL_DUMMY_ADDRESS ()
 	  && (pc) <= (CALL_DUMMY_ADDRESS () + DECR_PC_AFTER_BREAK));
 }


 /* Function: frame_chain_valid
    Returns true for a user frame or a call_function_by_hand dummy frame,
    and false for the CRT0 start-up frame.  Purpose is to terminate backtrace */

 int
 generic_file_frame_chain_valid (CORE_ADDR fp, struct frame_info *fi)
 {
   if (DEPRECATED_PC_IN_CALL_DUMMY (frame_pc_unwind (fi), fp, fp))
     return 1;			/* don't prune CALL_DUMMY frames */
   else				/* fall back to default algorithm (see frame.h) */
     return (fp != 0
 	    && (INNER_THAN (get_frame_base (fi), fp)
 		|| get_frame_base (fi) == fp)
 	    && !inside_entry_file (frame_pc_unwind (fi)));
 }

 int
 generic_func_frame_chain_valid (CORE_ADDR fp, struct frame_info *fi)
 {
   if (DEPRECATED_USE_GENERIC_DUMMY_FRAMES
       && DEPRECATED_PC_IN_CALL_DUMMY (get_frame_pc (fi), 0, 0))
     return 1;			/* don't prune CALL_DUMMY frames */
   else				/* fall back to default algorithm (see frame.h) */
     return (fp != 0
 	    && (INNER_THAN (get_frame_base (fi), fp)
 		|| get_frame_base (fi) == fp)
 	    && !inside_main_func (get_frame_pc (fi))
 	    && !inside_entry_func (get_frame_pc (fi)));
 }
	/* Get info from stack frames; convert between frames, blocks,
	functions and pc values.

	Copyright 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994,
	1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002 Free Software
	Foundation, Inc.

	This file is part of GDB.

	This program is free software; you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation; either version 2 of the License, or
	(at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program; if not, write to the Free Software
	Foundation, Inc., 59 Temple Place - Suite 330,
	Boston, MA 02111-1307, USA. */

	#include "defs.h"
	#include "symtab.h"
	#include "bfd.h"
	#include "symfile.h"
	#include "objfiles.h"
	#include "frame.h"
	#include "gdbcore.h"
	#include "value.h" /* for read_register */
	#include "target.h" /* for target_has_stack */
	#include "inferior.h" /* for read_pc */
	#include "annotate.h"
	#include "regcache.h"
	#include "gdb_assert.h"
	#include "dummy-frame.h"

	/* Prototypes for exported functions. */

	void _initialize_blockframe (void);

	/* A default FRAME_CHAIN_VALID, in the form that is suitable for most
	targets. If FRAME_CHAIN_VALID returns zero it means that the given
	frame is the outermost one and has no caller. */

	int
	file_frame_chain_valid (CORE_ADDR chain, struct frame_info *thisframe)
	{
	return ((chain) != 0
	&& !inside_entry_file (frame_pc_unwind (thisframe)));
	}

	/* Use the alternate method of avoiding running up off the end of the
	frame chain or following frames back into the startup code. See
	the comments in objfiles.h. */

	int
	func_frame_chain_valid (CORE_ADDR chain, struct frame_info *thisframe)
	{
	return ((chain) != 0
	&& !inside_main_func (get_frame_pc (thisframe))
	&& !inside_entry_func (get_frame_pc (thisframe)));
	}

	/* A very simple method of determining a valid frame */

	int
	nonnull_frame_chain_valid (CORE_ADDR chain, struct frame_info *thisframe)
	{
	return ((chain) != 0);
	}

	/* Is ADDR inside the startup file? Note that if your machine
	has a way to detect the bottom of the stack, there is no need
	to call this function from FRAME_CHAIN_VALID; the reason for
	doing so is that some machines have no way of detecting bottom
	of stack.

	A PC of zero is always considered to be the bottom of the stack. */

	int
	inside_entry_file (CORE_ADDR addr)
	{
	if (addr == 0)
	return 1;
	if (symfile_objfile == 0)
	return 0;
	if (CALL_DUMMY_LOCATION == AT_ENTRY_POINT)
	{
	/* Do not stop backtracing if the pc is in the call dummy
	at the entry point. */
	/* FIXME: Won't always work with zeros for the last two arguments */
	if (DEPRECATED_PC_IN_CALL_DUMMY (addr, 0, 0))
	return 0;
	}
	return (addr >= symfile_objfile->ei.entry_file_lowpc &&
	addr < symfile_objfile->ei.entry_file_highpc);
	}

	/* Test a specified PC value to see if it is in the range of addresses
	that correspond to the main() function. See comments above for why
	we might want to do this.

	Typically called from FRAME_CHAIN_VALID.

	A PC of zero is always considered to be the bottom of the stack. */

	int
	inside_main_func (CORE_ADDR pc)
	{
	if (pc == 0)
	return 1;
	if (symfile_objfile == 0)
	return 0;

	/* If the addr range is not set up at symbol reading time, set it up now.
	This is for FRAME_CHAIN_VALID_ALTERNATE. I do this for coff, because
	it is unable to set it up and symbol reading time. */

	if (symfile_objfile->ei.main_func_lowpc == INVALID_ENTRY_LOWPC &&
	symfile_objfile->ei.main_func_highpc == INVALID_ENTRY_HIGHPC)
	{
	struct symbol *mainsym;

	mainsym = lookup_symbol (main_name (), NULL, VAR_NAMESPACE, NULL, NULL);
	if (mainsym && SYMBOL_CLASS (mainsym) == LOC_BLOCK)
	{
	symfile_objfile->ei.main_func_lowpc =
	BLOCK_START (SYMBOL_BLOCK_VALUE (mainsym));
	symfile_objfile->ei.main_func_highpc =
	BLOCK_END (SYMBOL_BLOCK_VALUE (mainsym));
	}
	}
	return (symfile_objfile->ei.main_func_lowpc <= pc &&
	symfile_objfile->ei.main_func_highpc > pc);
	}

	/* Test a specified PC value to see if it is in the range of addresses
	that correspond to the process entry point function. See comments
	in objfiles.h for why we might want to do this.

	Typically called from FRAME_CHAIN_VALID.

	A PC of zero is always considered to be the bottom of the stack. */

	int
	inside_entry_func (CORE_ADDR pc)
	{
	if (pc == 0)
	return 1;
	if (symfile_objfile == 0)
	return 0;
	if (CALL_DUMMY_LOCATION == AT_ENTRY_POINT)
	{
	/* Do not stop backtracing if the pc is in the call dummy
	at the entry point. */
	/* FIXME: Won't always work with zeros for the last two arguments */
	if (DEPRECATED_PC_IN_CALL_DUMMY (pc, 0, 0))
	return 0;
	}
	return (symfile_objfile->ei.entry_func_lowpc <= pc &&
	symfile_objfile->ei.entry_func_highpc > pc);
	}

	/* Return nonzero if the function for this frame lacks a prologue. Many
	machines can define FRAMELESS_FUNCTION_INVOCATION to just call this
	function. */

	int
	frameless_look_for_prologue (struct frame_info *frame)
	{
	CORE_ADDR func_start, after_prologue;

	func_start = get_pc_function_start (get_frame_pc (frame));
	if (func_start)
	{
	func_start += FUNCTION_START_OFFSET;
	/* This is faster, since only care whether there is a
	prologue, not how long it is. */
	return PROLOGUE_FRAMELESS_P (func_start);
	}
	else if (get_frame_pc (frame) == 0)
	/* A frame with a zero PC is usually created by dereferencing a
	NULL function pointer, normally causing an immediate core dump
	of the inferior. Mark function as frameless, as the inferior
	has no chance of setting up a stack frame. */
	return 1;
	else
	/* If we can't find the start of the function, we don't really
	know whether the function is frameless, but we should be able
	to get a reasonable (i.e. best we can do under the
	circumstances) backtrace by saying that it isn't. */
	return 0;
	}

	/* return the address of the PC for the given FRAME, ie the current PC value
	if FRAME is the innermost frame, or the address adjusted to point to the
	call instruction if not. */

	CORE_ADDR
	frame_address_in_block (struct frame_info *frame)
	{
	CORE_ADDR pc = get_frame_pc (frame);

	/* If we are not in the innermost frame, and we are not interrupted
	by a signal, frame->pc points to the instruction following the
	call. As a consequence, we need to get the address of the previous
	instruction. Unfortunately, this is not straightforward to do, so
	we just use the address minus one, which is a good enough
	approximation. */
	/* FIXME: cagney/2002-11-10: Should this instead test for
	NORMAL_FRAME? A dummy frame (in fact all the abnormal frames)
	save the PC value in the block. */
	if (get_next_frame (frame) != 0
	&& get_frame_type (get_next_frame (frame)) != SIGTRAMP_FRAME)
	--pc;

	return pc;
	}

	/* Return the innermost lexical block in execution
	in a specified stack frame. The frame address is assumed valid.

	If ADDR_IN_BLOCK is non-zero, set *ADDR_IN_BLOCK to the exact code
	address we used to choose the block. We use this to find a source
	line, to decide which macro definitions are in scope.

	The value returned in *ADDR_IN_BLOCK isn't necessarily the frame's
	PC, and may not really be a valid PC at all. For example, in the
	caller of a function declared to never return, the code at the
	return address will never be reached, so the call instruction may
	be the very last instruction in the block. So the address we use
	to choose the block is actually one byte before the return address
	--- hopefully pointing us at the call instruction, or its delay
	slot instruction. */

	struct block *
	get_frame_block (struct frame_info frame, CORE_ADDR addr_in_block)
	{
	const CORE_ADDR pc = frame_address_in_block (frame);

	if (addr_in_block)
	*addr_in_block = pc;

	return block_for_pc (pc);
	}

	CORE_ADDR
	get_pc_function_start (CORE_ADDR pc)
	{
	register struct block *bl;
	register struct symbol *symbol;
	register struct minimal_symbol *msymbol;
	CORE_ADDR fstart;

	if ((bl = block_for_pc (pc)) != NULL &&
	(symbol = block_function (bl)) != NULL)
	{
	bl = SYMBOL_BLOCK_VALUE (symbol);
	fstart = BLOCK_START (bl);
	}
	else if ((msymbol = lookup_minimal_symbol_by_pc (pc)) != NULL)
	{
	fstart = SYMBOL_VALUE_ADDRESS (msymbol);
	if (!find_pc_section (fstart))
	return 0;
	}
	else
	{
	fstart = 0;
	}
	return (fstart);
	}

	/* Return the symbol for the function executing in frame FRAME. */

	struct symbol *
	get_frame_function (struct frame_info *frame)
	{
	register struct block *bl = get_frame_block (frame, 0);
	if (bl == 0)
	return 0;
	return block_function (bl);
	}


	/* Return the blockvector immediately containing the innermost lexical block
	containing the specified pc value and section, or 0 if there is none.
	PINDEX is a pointer to the index value of the block. If PINDEX
	is NULL, we don't pass this information back to the caller. */

	struct blockvector *
	blockvector_for_pc_sect (register CORE_ADDR pc, struct sec *section,
	int pindex, struct symtab symtab)
	{
	register struct block *b;
	register int bot, top, half;
	struct blockvector *bl;

	if (symtab == 0) /* if no symtab specified by caller */
	{
	/* First search all symtabs for one whose file contains our pc */
	if ((symtab = find_pc_sect_symtab (pc, section)) == 0)
	return 0;
	}

	bl = BLOCKVECTOR (symtab);
	b = BLOCKVECTOR_BLOCK (bl, 0);

	/* Then search that symtab for the smallest block that wins. */
	/* Use binary search to find the last block that starts before PC. */

	bot = 0;
	top = BLOCKVECTOR_NBLOCKS (bl);

	while (top - bot > 1)
	{
	half = (top - bot + 1) >> 1;
	b = BLOCKVECTOR_BLOCK (bl, bot + half);
	if (BLOCK_START (b) <= pc)
	bot += half;
	else
	top = bot + half;
	}

	/* Now search backward for a block that ends after PC. */

	while (bot >= 0)
	{
	b = BLOCKVECTOR_BLOCK (bl, bot);
	if (BLOCK_END (b) > pc)
	{
	if (pindex)
	*pindex = bot;
	return bl;
	}
	bot--;
	}
	return 0;
	}

	/* Return the blockvector immediately containing the innermost lexical block
	containing the specified pc value, or 0 if there is none.
	Backward compatibility, no section. */

	struct blockvector *
	blockvector_for_pc (register CORE_ADDR pc, int *pindex)
	{
	return blockvector_for_pc_sect (pc, find_pc_mapped_section (pc),
	pindex, NULL);
	}

	/* Return the innermost lexical block containing the specified pc value
	in the specified section, or 0 if there is none. */

	struct block *
	block_for_pc_sect (register CORE_ADDR pc, struct sec *section)
	{
	register struct blockvector *bl;
	int index;

	bl = blockvector_for_pc_sect (pc, section, &index, NULL);
	if (bl)
	return BLOCKVECTOR_BLOCK (bl, index);
	return 0;
	}

	/* Return the innermost lexical block containing the specified pc value,
	or 0 if there is none. Backward compatibility, no section. */

	struct block *
	block_for_pc (register CORE_ADDR pc)
	{
	return block_for_pc_sect (pc, find_pc_mapped_section (pc));
	}

	/* Return the function containing pc value PC in section SECTION.
	Returns 0 if function is not known. */

	struct symbol *
	find_pc_sect_function (CORE_ADDR pc, struct sec *section)
	{
	register struct block *b = block_for_pc_sect (pc, section);
	if (b == 0)
	return 0;
	return block_function (b);
	}

	/* Return the function containing pc value PC.
	Returns 0 if function is not known. Backward compatibility, no section */

	struct symbol *
	find_pc_function (CORE_ADDR pc)
	{
	return find_pc_sect_function (pc, find_pc_mapped_section (pc));
	}

	/* These variables are used to cache the most recent result
	* of find_pc_partial_function. */

	static CORE_ADDR cache_pc_function_low = 0;
	static CORE_ADDR cache_pc_function_high = 0;
	static char *cache_pc_function_name = 0;
	static struct sec *cache_pc_function_section = NULL;

	/* Clear cache, e.g. when symbol table is discarded. */

	void
	clear_pc_function_cache (void)
	{
	cache_pc_function_low = 0;
	cache_pc_function_high = 0;
	cache_pc_function_name = (char *) 0;
	cache_pc_function_section = NULL;
	}

	/* Finds the "function" (text symbol) that is smaller than PC but
	greatest of all of the potential text symbols in SECTION. Sets
	NAME and/or ADDRESS conditionally if that pointer is non-null.
	If ENDADDR is non-null, then set *ENDADDR to be the end of the
	function (exclusive), but passing ENDADDR as non-null means that
	the function might cause symbols to be read. This function either
	succeeds or fails (not halfway succeeds). If it succeeds, it sets
	NAME, ADDRESS, and *ENDADDR to real information and returns 1.
	If it fails, it sets NAME, ADDRESS, and *ENDADDR to zero and
	returns 0. */

	int
	find_pc_sect_partial_function (CORE_ADDR pc, asection section, char *name,
	CORE_ADDR address, CORE_ADDR endaddr)
	{
	struct partial_symtab *pst;
	struct symbol *f;
	struct minimal_symbol *msymbol;
	struct partial_symbol *psb;
	struct obj_section *osect;
	int i;
	CORE_ADDR mapped_pc;

	mapped_pc = overlay_mapped_address (pc, section);

	if (mapped_pc >= cache_pc_function_low
	&& mapped_pc < cache_pc_function_high
	&& section == cache_pc_function_section)
	goto return_cached_value;

	/* If sigtramp is in the u area, it counts as a function (especially
	important for step_1). */
	if (SIGTRAMP_START_P () && PC_IN_SIGTRAMP (mapped_pc, (char *) NULL))
	{
	cache_pc_function_low = SIGTRAMP_START (mapped_pc);
	cache_pc_function_high = SIGTRAMP_END (mapped_pc);
	cache_pc_function_name = "<sigtramp>";
	cache_pc_function_section = section;
	goto return_cached_value;
	}

	msymbol = lookup_minimal_symbol_by_pc_section (mapped_pc, section);
	pst = find_pc_sect_psymtab (mapped_pc, section);
	if (pst)
	{
	/* Need to read the symbols to get a good value for the end address. */
	if (endaddr != NULL && !pst->readin)
	{
	/* Need to get the terminal in case symbol-reading produces
	output. */
	target_terminal_ours_for_output ();
	PSYMTAB_TO_SYMTAB (pst);
	}

	if (pst->readin)
	{
	/* Checking whether the msymbol has a larger value is for the
	"pathological" case mentioned in print_frame_info. */
	f = find_pc_sect_function (mapped_pc, section);
	if (f != NULL
	&& (msymbol == NULL
	\|\| (BLOCK_START (SYMBOL_BLOCK_VALUE (f))
	>= SYMBOL_VALUE_ADDRESS (msymbol))))
	{
	cache_pc_function_low = BLOCK_START (SYMBOL_BLOCK_VALUE (f));
	cache_pc_function_high = BLOCK_END (SYMBOL_BLOCK_VALUE (f));
	cache_pc_function_name = SYMBOL_NAME (f);
	cache_pc_function_section = section;
	goto return_cached_value;
	}
	}
	else
	{
	/* Now that static symbols go in the minimal symbol table, perhaps
	we could just ignore the partial symbols. But at least for now
	we use the partial or minimal symbol, whichever is larger. */
	psb = find_pc_sect_psymbol (pst, mapped_pc, section);

	if (psb
	&& (msymbol == NULL \|\|
	(SYMBOL_VALUE_ADDRESS (psb)
	>= SYMBOL_VALUE_ADDRESS (msymbol))))
	{
	/* This case isn't being cached currently. */
	if (address)
	*address = SYMBOL_VALUE_ADDRESS (psb);
	if (name)
	*name = SYMBOL_NAME (psb);
	/* endaddr non-NULL can't happen here. */
	return 1;
	}
	}
	}

	/* Not in the normal symbol tables, see if the pc is in a known section.
	If it's not, then give up. This ensures that anything beyond the end
	of the text seg doesn't appear to be part of the last function in the
	text segment. */

	osect = find_pc_sect_section (mapped_pc, section);

	if (!osect)
	msymbol = NULL;

	/* Must be in the minimal symbol table. */
	if (msymbol == NULL)
	{
	/* No available symbol. */
	if (name != NULL)
	*name = 0;
	if (address != NULL)
	*address = 0;
	if (endaddr != NULL)
	*endaddr = 0;
	return 0;
	}

	cache_pc_function_low = SYMBOL_VALUE_ADDRESS (msymbol);
	cache_pc_function_name = SYMBOL_NAME (msymbol);
	cache_pc_function_section = section;

	/* Use the lesser of the next minimal symbol in the same section, or
	the end of the section, as the end of the function. */

	/* Step over other symbols at this same address, and symbols in
	other sections, to find the next symbol in this section with
	a different address. */

	for (i = 1; SYMBOL_NAME (msymbol + i) != NULL; i++)
	{
	if (SYMBOL_VALUE_ADDRESS (msymbol + i) != SYMBOL_VALUE_ADDRESS (msymbol)
	&& SYMBOL_BFD_SECTION (msymbol + i) == SYMBOL_BFD_SECTION (msymbol))
	break;
	}

	if (SYMBOL_NAME (msymbol + i) != NULL
	&& SYMBOL_VALUE_ADDRESS (msymbol + i) < osect->endaddr)
	cache_pc_function_high = SYMBOL_VALUE_ADDRESS (msymbol + i);
	else
	/* We got the start address from the last msymbol in the objfile.
	So the end address is the end of the section. */
	cache_pc_function_high = osect->endaddr;

	return_cached_value:

	if (address)
	{
	if (pc_in_unmapped_range (pc, section))
	*address = overlay_unmapped_address (cache_pc_function_low, section);
	else
	*address = cache_pc_function_low;
	}

	if (name)
	*name = cache_pc_function_name;

	if (endaddr)
	{
	if (pc_in_unmapped_range (pc, section))
	{
	/* Because the high address is actually beyond the end of
	the function (and therefore possibly beyond the end of
	the overlay), we must actually convert (high - 1) and
	then add one to that. */

	*endaddr = 1 + overlay_unmapped_address (cache_pc_function_high - 1,
	section);
	}
	else
	*endaddr = cache_pc_function_high;
	}

	return 1;
	}

	/* Backward compatibility, no section argument. */

	int
	find_pc_partial_function (CORE_ADDR pc, char *name, CORE_ADDR address,
	CORE_ADDR *endaddr)
	{
	asection *section;

	section = find_pc_overlay (pc);
	return find_pc_sect_partial_function (pc, section, name, address, endaddr);
	}

	/* Return the innermost stack frame executing inside of BLOCK,
	or NULL if there is no such frame. If BLOCK is NULL, just return NULL. */

	struct frame_info *
	block_innermost_frame (struct block *block)
	{
	struct frame_info *frame;
	register CORE_ADDR start;
	register CORE_ADDR end;
	CORE_ADDR calling_pc;

	if (block == NULL)
	return NULL;

	start = BLOCK_START (block);
	end = BLOCK_END (block);

	frame = NULL;
	while (1)
	{
	frame = get_prev_frame (frame);
	if (frame == NULL)
	return NULL;
	calling_pc = frame_address_in_block (frame);
	if (calling_pc >= start && calling_pc < end)
	return frame;
	}
	}

	/* Are we in a call dummy? The code below which allows DECR_PC_AFTER_BREAK
	below is for infrun.c, which may give the macro a pc without that
	subtracted out. */

	extern CORE_ADDR text_end;

	int
	deprecated_pc_in_call_dummy_before_text_end (CORE_ADDR pc, CORE_ADDR sp,
	CORE_ADDR frame_address)
	{
	return ((pc) >= text_end - CALL_DUMMY_LENGTH
	&& (pc) <= text_end + DECR_PC_AFTER_BREAK);
	}

	int
	deprecated_pc_in_call_dummy_after_text_end (CORE_ADDR pc, CORE_ADDR sp,
	CORE_ADDR frame_address)
	{
	return ((pc) >= text_end
	&& (pc) <= text_end + CALL_DUMMY_LENGTH + DECR_PC_AFTER_BREAK);
	}

	/* Is the PC in a call dummy? SP and FRAME_ADDRESS are the bottom and
	top of the stack frame which we are checking, where "bottom" and
	"top" refer to some section of memory which contains the code for
	the call dummy. Calls to this macro assume that the contents of
	SP_REGNUM and FP_REGNUM (or the saved values thereof), respectively,
	are the things to pass.

	This won't work on the 29k, where SP_REGNUM and FP_REGNUM don't
	have that meaning, but the 29k doesn't use ON_STACK. This could be
	fixed by generalizing this scheme, perhaps by passing in a frame
	and adding a few fields, at least on machines which need them for
	DEPRECATED_PC_IN_CALL_DUMMY.

	Something simpler, like checking for the stack segment, doesn't work,
	since various programs (threads implementations, gcc nested function
	stubs, etc) may either allocate stack frames in another segment, or
	allocate other kinds of code on the stack. */

	int
	deprecated_pc_in_call_dummy_on_stack (CORE_ADDR pc, CORE_ADDR sp,
	CORE_ADDR frame_address)
	{
	return (INNER_THAN ((sp), (pc))
	&& (frame_address != 0)
	&& INNER_THAN ((pc), (frame_address)));
	}

	int
	deprecated_pc_in_call_dummy_at_entry_point (CORE_ADDR pc, CORE_ADDR sp,
	CORE_ADDR frame_address)
	{
	return ((pc) >= CALL_DUMMY_ADDRESS ()
	&& (pc) <= (CALL_DUMMY_ADDRESS () + DECR_PC_AFTER_BREAK));
	}


	/* Function: frame_chain_valid
	Returns true for a user frame or a call_function_by_hand dummy frame,
	and false for the CRT0 start-up frame. Purpose is to terminate backtrace */

	int
	generic_file_frame_chain_valid (CORE_ADDR fp, struct frame_info *fi)
	{
	if (DEPRECATED_PC_IN_CALL_DUMMY (frame_pc_unwind (fi), fp, fp))
	return 1; /* don't prune CALL_DUMMY frames */
	else /* fall back to default algorithm (see frame.h) */
	return (fp != 0
	&& (INNER_THAN (get_frame_base (fi), fp)
	\|\| get_frame_base (fi) == fp)
	&& !inside_entry_file (frame_pc_unwind (fi)));
	}

	int
	generic_func_frame_chain_valid (CORE_ADDR fp, struct frame_info *fi)
	{
	if (DEPRECATED_USE_GENERIC_DUMMY_FRAMES
	&& DEPRECATED_PC_IN_CALL_DUMMY (get_frame_pc (fi), 0, 0))
	return 1; /* don't prune CALL_DUMMY frames */
	else /* fall back to default algorithm (see frame.h) */
	return (fp != 0
	&& (INNER_THAN (get_frame_base (fi), fp)
	\|\| get_frame_base (fi) == fp)
	&& !inside_main_func (get_frame_pc (fi))
	&& !inside_entry_func (get_frame_pc (fi)));
	}