Initial creation of sourceware repositorygdb-4_18-branchpoint

1 files changed, 1301 insertions, 0 deletions

diff --git a/gdb/blockframe.c b/gdb/blockframe.c
new file mode 100644
index 0000000..9366ca6
--- /dev/null
+++ b/gdb/blockframe.c
@@ -0,0 +1,1301 @@
+/* Get info from stack frames;
+   convert between frames, blocks, functions and pc values.
+   Copyright 1986, 87, 88, 89, 91, 94, 95, 96, 97, 1998
+             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"
+
+/* Prototypes for exported functions. */
+
+void _initialize_blockframe PARAMS ((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
+default_frame_chain_valid (chain, thisframe)
+     CORE_ADDR chain;
+     struct frame_info *thisframe;
+{
+  return ((chain) != 0
+	  && !inside_main_func ((thisframe) -> pc)
+	  && !inside_entry_func ((thisframe) -> pc));
+}
+
+/* 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
+alternate_frame_chain_valid (chain, thisframe)
+     CORE_ADDR chain;
+     struct frame_info *thisframe;
+{
+  return ((chain) != 0
+	  && !inside_entry_file (FRAME_SAVED_PC (thisframe)));
+}
+
+/* A very simple method of determining a valid frame */
+   
+int
+nonnull_frame_chain_valid (chain, thisframe)
+     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 (addr)
+     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 (PC_IN_CALL_DUMMY (addr, 0, 0))	
+    return 0;
+#endif
+  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 (pc)
+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", 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 (pc)
+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 (PC_IN_CALL_DUMMY (pc, 0, 0))
+    return 0;
+#endif
+  return (symfile_objfile -> ei.entry_func_lowpc  <= pc &&
+	  symfile_objfile -> ei.entry_func_highpc > pc);
+}
+
+/* Info about the innermost stack frame (contents of FP register) */
+
+static struct frame_info *current_frame;
+
+/* Cache for frame addresses already read by gdb.  Valid only while
+   inferior is stopped.  Control variables for the frame cache should
+   be local to this module.  */
+
+static struct obstack frame_cache_obstack;
+
+void *
+frame_obstack_alloc (size)
+     unsigned long size;
+{
+  return obstack_alloc (&frame_cache_obstack, size);
+}
+
+void
+frame_saved_regs_zalloc (fi)
+     struct frame_info *fi;
+{
+  fi->saved_regs = (CORE_ADDR*)
+    frame_obstack_alloc (SIZEOF_FRAME_SAVED_REGS);
+  memset (fi->saved_regs, 0, SIZEOF_FRAME_SAVED_REGS);
+}
+
+
+/* Return the innermost (currently executing) stack frame.  */
+
+struct frame_info *
+get_current_frame ()
+{
+  if (current_frame == NULL)
+    {
+      if (target_has_stack)
+	current_frame = create_new_frame (read_fp (), read_pc ());
+      else
+	error ("No stack.");
+    }
+  return current_frame;
+}
+
+void
+set_current_frame (frame)
+     struct frame_info *frame;
+{
+  current_frame = frame;
+}
+
+/* Create an arbitrary (i.e. address specified by user) or innermost frame.
+   Always returns a non-NULL value.  */
+
+struct frame_info *
+create_new_frame (addr, pc)
+     CORE_ADDR addr;
+     CORE_ADDR pc;
+{
+  struct frame_info *fi;
+  char *name;
+
+  fi = (struct frame_info *)
+    obstack_alloc (&frame_cache_obstack,
+		   sizeof (struct frame_info));
+
+  /* Arbitrary frame */
+  fi->saved_regs = NULL;
+  fi->next = NULL;
+  fi->prev = NULL;
+  fi->frame = addr;
+  fi->pc = pc;
+  find_pc_partial_function (pc, &name, (CORE_ADDR *)NULL,(CORE_ADDR *)NULL);
+  fi->signal_handler_caller = IN_SIGTRAMP (fi->pc, name);
+
+#ifdef INIT_EXTRA_FRAME_INFO
+  INIT_EXTRA_FRAME_INFO (0, fi);
+#endif
+
+  return fi;
+}
+
+/* Return the frame that called FI.
+   If FI is the original frame (it has no caller), return 0.  */
+
+struct frame_info *
+get_prev_frame (frame)
+     struct frame_info *frame;
+{
+  return get_prev_frame_info (frame);
+}
+
+/* Return the frame that FRAME calls (NULL if FRAME is the innermost
+   frame).  */
+
+struct frame_info *
+get_next_frame (frame)
+     struct frame_info *frame;
+{
+  return frame->next;
+}
+
+/* Flush the entire frame cache.  */
+
+void
+flush_cached_frames ()
+{
+  /* Since we can't really be sure what the first object allocated was */
+  obstack_free (&frame_cache_obstack, 0);
+  obstack_init (&frame_cache_obstack);
+
+  current_frame = NULL;  /* Invalidate cache */
+  select_frame (NULL, -1);
+  annotate_frames_invalid ();
+}
+
+/* Flush the frame cache, and start a new one if necessary.  */
+
+void
+reinit_frame_cache ()
+{
+  flush_cached_frames ();
+
+  /* FIXME: The inferior_pid test is wrong if there is a corefile.  */
+  if (inferior_pid != 0)
+    {
+      select_frame (get_current_frame (), 0);
+    }
+}
+
+/* If a machine allows frameless functions, it should define a macro
+   FRAMELESS_FUNCTION_INVOCATION(FI, FRAMELESS) in param.h.  FI is the struct
+   frame_info for the frame, and FRAMELESS should be set to nonzero
+   if it represents a frameless function invocation.  */
+
+/* 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 (frame)
+     struct frame_info *frame;
+{
+  CORE_ADDR func_start, after_prologue;
+  func_start = get_pc_function_start (frame->pc);
+  if (func_start)
+    {
+      func_start += FUNCTION_START_OFFSET;
+      after_prologue = func_start;
+#ifdef SKIP_PROLOGUE_FRAMELESS_P
+      /* This is faster, since only care whether there *is* a prologue,
+	 not how long it is.  */
+      SKIP_PROLOGUE_FRAMELESS_P (after_prologue);
+#else
+      SKIP_PROLOGUE (after_prologue);
+#endif
+      return after_prologue == func_start;
+    }
+  else if (frame->pc == 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;
+}
+
+/* Default a few macros that people seldom redefine.  */
+
+#if !defined (INIT_FRAME_PC)
+#define INIT_FRAME_PC(fromleaf, prev) \
+  prev->pc = (fromleaf ? SAVED_PC_AFTER_CALL (prev->next) : \
+	      prev->next ? FRAME_SAVED_PC (prev->next) : read_pc ());
+#endif
+
+#ifndef FRAME_CHAIN_COMBINE
+#define	FRAME_CHAIN_COMBINE(chain, thisframe) (chain)
+#endif
+
+/* Return a structure containing various interesting information
+   about the frame that called NEXT_FRAME.  Returns NULL
+   if there is no such frame.  */
+
+struct frame_info *
+get_prev_frame_info (next_frame)
+     struct frame_info *next_frame;
+{
+  CORE_ADDR address = 0;
+  struct frame_info *prev;
+  int fromleaf = 0;
+  char *name;
+
+  /* If the requested entry is in the cache, return it.
+     Otherwise, figure out what the address should be for the entry
+     we're about to add to the cache. */
+
+  if (!next_frame)
+    {
+#if 0
+      /* This screws value_of_variable, which just wants a nice clean
+	 NULL return from block_innermost_frame if there are no frames.
+	 I don't think I've ever seen this message happen otherwise.
+	 And returning NULL here is a perfectly legitimate thing to do.  */
+      if (!current_frame)
+	{
+	  error ("You haven't set up a process's stack to examine.");
+	}
+#endif
+
+      return current_frame;
+    }
+
+  /* If we have the prev one, return it */
+  if (next_frame->prev)
+    return next_frame->prev;
+
+  /* On some machines it is possible to call a function without
+     setting up a stack frame for it.  On these machines, we
+     define this macro to take two args; a frameinfo pointer
+     identifying a frame and a variable to set or clear if it is
+     or isn't leafless.  */
+#ifdef FRAMELESS_FUNCTION_INVOCATION
+  /* Still don't want to worry about this except on the innermost
+     frame.  This macro will set FROMLEAF if NEXT_FRAME is a
+     frameless function invocation.  */
+  if (!(next_frame->next))
+    {
+      FRAMELESS_FUNCTION_INVOCATION (next_frame, fromleaf);
+      if (fromleaf)
+	address = FRAME_FP (next_frame);
+    }
+#endif
+
+  if (!fromleaf)
+    {
+      /* Two macros defined in tm.h specify the machine-dependent
+	 actions to be performed here.
+	 First, get the frame's chain-pointer.
+	 If that is zero, the frame is the outermost frame or a leaf
+	 called by the outermost frame.  This means that if start
+	 calls main without a frame, we'll return 0 (which is fine
+	 anyway).
+
+	 Nope; there's a problem.  This also returns when the current
+	 routine is a leaf of main.  This is unacceptable.  We move
+	 this to after the ffi test; I'd rather have backtraces from
+	 start go curfluy than have an abort called from main not show
+	 main.  */
+      address = FRAME_CHAIN (next_frame);
+      if (!FRAME_CHAIN_VALID (address, next_frame))
+	return 0;
+      address = FRAME_CHAIN_COMBINE (address, next_frame);
+    }
+  if (address == 0)
+    return 0;
+
+  prev = (struct frame_info *)
+    obstack_alloc (&frame_cache_obstack,
+		   sizeof (struct frame_info));
+
+  prev->saved_regs = NULL;
+  if (next_frame)
+    next_frame->prev = prev;
+  prev->next = next_frame;
+  prev->prev = (struct frame_info *) 0;
+  prev->frame = address;
+  prev->signal_handler_caller = 0;
+
+/* This change should not be needed, FIXME!  We should
+   determine whether any targets *need* INIT_FRAME_PC to happen
+   after INIT_EXTRA_FRAME_INFO and come up with a simple way to
+   express what goes on here.
+
+      INIT_EXTRA_FRAME_INFO is called from two places: create_new_frame
+      		(where the PC is already set up) and here (where it isn't).
+      INIT_FRAME_PC is only called from here, always after
+      		INIT_EXTRA_FRAME_INFO.
+   
+   The catch is the MIPS, where INIT_EXTRA_FRAME_INFO requires the PC
+   value (which hasn't been set yet).  Some other machines appear to
+   require INIT_EXTRA_FRAME_INFO before they can do INIT_FRAME_PC.  Phoo.
+
+   We shouldn't need INIT_FRAME_PC_FIRST to add more complication to
+   an already overcomplicated part of GDB.   gnu@cygnus.com, 15Sep92.
+
+   Assuming that some machines need INIT_FRAME_PC after
+   INIT_EXTRA_FRAME_INFO, one possible scheme:
+
+   SETUP_INNERMOST_FRAME()
+     Default version is just create_new_frame (read_fp ()),
+     read_pc ()).  Machines with extra frame info would do that (or the
+     local equivalent) and then set the extra fields.
+   SETUP_ARBITRARY_FRAME(argc, argv)
+     Only change here is that create_new_frame would no longer init extra
+     frame info; SETUP_ARBITRARY_FRAME would have to do that.
+   INIT_PREV_FRAME(fromleaf, prev)
+     Replace INIT_EXTRA_FRAME_INFO and INIT_FRAME_PC.  This should
+     also return a flag saying whether to keep the new frame, or
+     whether to discard it, because on some machines (e.g.  mips) it
+     is really awkward to have FRAME_CHAIN_VALID called *before*
+     INIT_EXTRA_FRAME_INFO (there is no good way to get information
+     deduced in FRAME_CHAIN_VALID into the extra fields of the new frame).
+   std_frame_pc(fromleaf, prev)
+     This is the default setting for INIT_PREV_FRAME.  It just does what
+     the default INIT_FRAME_PC does.  Some machines will call it from
+     INIT_PREV_FRAME (either at the beginning, the end, or in the middle).
+     Some machines won't use it.
+   kingdon@cygnus.com, 13Apr93, 31Jan94, 14Dec94.  */
+
+#ifdef INIT_FRAME_PC_FIRST
+  INIT_FRAME_PC_FIRST (fromleaf, prev);
+#endif
+
+#ifdef INIT_EXTRA_FRAME_INFO
+  INIT_EXTRA_FRAME_INFO(fromleaf, prev);
+#endif
+
+  /* This entry is in the frame queue now, which is good since
+     FRAME_SAVED_PC may use that queue to figure out its value
+     (see tm-sparc.h).  We want the pc saved in the inferior frame. */
+  INIT_FRAME_PC(fromleaf, prev);
+
+  /* If ->frame and ->pc are unchanged, we are in the process of getting
+     ourselves into an infinite backtrace.  Some architectures check this
+     in FRAME_CHAIN or thereabouts, but it seems like there is no reason
+     this can't be an architecture-independent check.  */
+  if (next_frame != NULL)
+    {
+      if (prev->frame == next_frame->frame
+	  && prev->pc == next_frame->pc)
+	{
+	  next_frame->prev = NULL;
+	  obstack_free (&frame_cache_obstack, prev);
+	  return NULL;
+	}
+    }
+
+  find_pc_partial_function (prev->pc, &name,
+			    (CORE_ADDR *)NULL,(CORE_ADDR *)NULL);
+  if (IN_SIGTRAMP (prev->pc, name))
+    prev->signal_handler_caller = 1;
+
+  return prev;
+}
+
+CORE_ADDR
+get_frame_pc (frame)
+     struct frame_info *frame;
+{
+  return frame->pc;
+}
+
+
+#ifdef FRAME_FIND_SAVED_REGS
+/* XXX - deprecated.  This is a compatibility function for targets
+   that do not yet implement FRAME_INIT_SAVED_REGS.  */
+/* Find the addresses in which registers are saved in FRAME.  */
+
+void
+get_frame_saved_regs (frame, saved_regs_addr)
+     struct frame_info *frame;
+     struct frame_saved_regs *saved_regs_addr;
+{
+  if (frame->saved_regs == NULL)
+    {
+      frame->saved_regs = (CORE_ADDR*)
+	frame_obstack_alloc (SIZEOF_FRAME_SAVED_REGS);
+    }
+  if (saved_regs_addr == NULL)
+    {
+      struct frame_saved_regs saved_regs;
+      FRAME_FIND_SAVED_REGS (frame, saved_regs);
+      memcpy (frame->saved_regs, &saved_regs, SIZEOF_FRAME_SAVED_REGS);
+    }
+  else
+    {
+      FRAME_FIND_SAVED_REGS (frame, *saved_regs_addr);
+      memcpy (frame->saved_regs, saved_regs_addr, SIZEOF_FRAME_SAVED_REGS);
+    }
+}
+#endif
+
+/* Return the innermost lexical block in execution
+   in a specified stack frame.  The frame address is assumed valid.  */
+
+struct block *
+get_frame_block (frame)
+     struct frame_info *frame;
+{
+  CORE_ADDR pc;
+
+  pc = frame->pc;
+  if (frame->next != 0 && frame->next->signal_handler_caller == 0)
+    /* We are not in the innermost frame and we were not interrupted
+       by a signal.  We need to subtract one to get the correct block,
+       in case the call instruction was the last instruction of the block.
+       If there are any machines on which the saved pc does not point to
+       after the call insn, we probably want to make frame->pc point after
+       the call insn anyway.  */
+    --pc;
+  return block_for_pc (pc);
+}
+
+struct block *
+get_current_block ()
+{
+  return block_for_pc (read_pc ());
+}
+
+CORE_ADDR
+get_pc_function_start (pc)
+     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);
+    }
+  else
+    {
+      fstart = 0;
+    }
+  return (fstart);
+}
+
+/* Return the symbol for the function executing in frame FRAME.  */
+
+struct symbol *
+get_frame_function (frame)
+     struct frame_info *frame;
+{
+  register struct block *bl = get_frame_block (frame);
+  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 (pc, section, pindex, symtab)
+     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 (pc, pindex)
+     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 (pc, section)
+     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 (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 (pc, section)
+     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 (pc)
+     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()
+{
+  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 (pc, section, name, address, endaddr)
+     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 defined SIGTRAMP_START
+  if (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;
+    }
+#endif
+
+  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 (pc, name, address, endaddr)
+     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 (block)
+     struct block *block;
+{
+  struct frame_info *frame;
+  register CORE_ADDR start;
+  register CORE_ADDR end;
+
+  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;
+      if (frame->pc >= start && frame->pc < end)
+	return frame;
+    }
+}
+
+/* Return the full FRAME which corresponds to the given CORE_ADDR
+   or NULL if no FRAME on the chain corresponds to CORE_ADDR.  */
+
+struct frame_info *
+find_frame_addr_in_frame_chain (frame_addr)
+     CORE_ADDR frame_addr;
+{
+  struct frame_info *frame = NULL;
+
+  if (frame_addr == (CORE_ADDR)0)
+    return NULL;
+
+  while (1)
+    {
+      frame = get_prev_frame (frame);
+      if (frame == NULL)
+	return NULL;
+      if (FRAME_FP (frame) == frame_addr)
+	return frame;
+    }
+}
+
+#ifdef SIGCONTEXT_PC_OFFSET
+/* Get saved user PC for sigtramp from sigcontext for BSD style sigtramp.  */
+
+CORE_ADDR
+sigtramp_saved_pc (frame)
+     struct frame_info *frame;
+{
+  CORE_ADDR sigcontext_addr;
+  char buf[TARGET_PTR_BIT / TARGET_CHAR_BIT];
+  int ptrbytes = TARGET_PTR_BIT / TARGET_CHAR_BIT;
+  int sigcontext_offs = (2 * TARGET_INT_BIT) / TARGET_CHAR_BIT;
+
+  /* Get sigcontext address, it is the third parameter on the stack.  */
+  if (frame->next)
+    sigcontext_addr = read_memory_integer (FRAME_ARGS_ADDRESS (frame->next)
+					   + FRAME_ARGS_SKIP
+					   + sigcontext_offs,
+					   ptrbytes);
+  else
+    sigcontext_addr = read_memory_integer (read_register (SP_REGNUM)
+					    + sigcontext_offs,
+					   ptrbytes);
+
+  /* Don't cause a memory_error when accessing sigcontext in case the stack
+     layout has changed or the stack is corrupt.  */
+  target_read_memory (sigcontext_addr + SIGCONTEXT_PC_OFFSET, buf, ptrbytes);
+  return extract_unsigned_integer (buf, ptrbytes);
+}
+#endif /* SIGCONTEXT_PC_OFFSET */
+
+#ifdef USE_GENERIC_DUMMY_FRAMES
+
+/*
+ * GENERIC DUMMY FRAMES
+ * 
+ * The following code serves to maintain the dummy stack frames for
+ * inferior function calls (ie. when gdb calls into the inferior via
+ * call_function_by_hand).  This code saves the machine state before 
+ * the call in host memory, so we must maintain an independant stack 
+ * and keep it consistant etc.  I am attempting to make this code 
+ * generic enough to be used by many targets.
+ *
+ * The cheapest and most generic way to do CALL_DUMMY on a new target
+ * is probably to define CALL_DUMMY to be empty, CALL_DUMMY_LENGTH to
+ * zero, and CALL_DUMMY_LOCATION to AT_ENTRY.  Then you must remember
+ * to define PUSH_RETURN_ADDRESS, because no call instruction will be
+ * being executed by the target.  Also FRAME_CHAIN_VALID as
+ * generic_frame_chain_valid.  */
+
+static struct dummy_frame *dummy_frame_stack = NULL;
+
+/* Function: find_dummy_frame(pc, fp, sp)
+   Search the stack of dummy frames for one matching the given PC, FP and SP.
+   This is the work-horse for pc_in_call_dummy and read_register_dummy     */
+
+char * 
+generic_find_dummy_frame (pc, fp)
+     CORE_ADDR pc;
+     CORE_ADDR fp;
+{
+  struct dummy_frame * dummyframe;
+
+  if (pc != entry_point_address ())
+    return 0;
+
+  for (dummyframe = dummy_frame_stack; dummyframe != NULL;
+       dummyframe = dummyframe->next)
+    if (fp == dummyframe->fp || fp == dummyframe->sp)
+      /* The frame in question lies between the saved fp and sp, inclusive */
+      return dummyframe->regs;
+
+  return 0;
+}
+
+/* Function: pc_in_call_dummy (pc, fp)
+   Return true if this is a dummy frame created by gdb for an inferior call */
+
+int
+generic_pc_in_call_dummy (pc, fp)
+     CORE_ADDR pc;
+     CORE_ADDR fp;
+{
+  /* if find_dummy_frame succeeds, then PC is in a call dummy */
+  return (generic_find_dummy_frame (pc, fp) != 0);
+}
+
+/* Function: read_register_dummy 
+   Find a saved register from before GDB calls a function in the inferior */
+
+CORE_ADDR
+generic_read_register_dummy (pc, fp, regno)
+     CORE_ADDR pc;
+     CORE_ADDR fp;
+     int regno;
+{
+  char *dummy_regs = generic_find_dummy_frame (pc, fp);
+
+  if (dummy_regs)
+    return extract_address (&dummy_regs[REGISTER_BYTE (regno)],
+			    REGISTER_RAW_SIZE(regno));
+  else
+    return 0;
+}
+
+/* Save all the registers on the dummy frame stack.  Most ports save the
+   registers on the target stack.  This results in lots of unnecessary memory
+   references, which are slow when debugging via a serial line.  Instead, we
+   save all the registers internally, and never write them to the stack.  The
+   registers get restored when the called function returns to the entry point,
+   where a breakpoint is laying in wait.  */
+
+void
+generic_push_dummy_frame ()
+{
+  struct dummy_frame *dummy_frame;
+  CORE_ADDR fp = (get_current_frame ())->frame;
+
+  /* check to see if there are stale dummy frames, 
+     perhaps left over from when a longjump took us out of a 
+     function that was called by the debugger */
+
+  dummy_frame = dummy_frame_stack;
+  while (dummy_frame)
+    if (INNER_THAN (dummy_frame->fp, fp))	/* stale -- destroy! */
+      {
+	dummy_frame_stack = dummy_frame->next;
+	free (dummy_frame);
+	dummy_frame = dummy_frame_stack;
+      }
+    else
+      dummy_frame = dummy_frame->next;
+
+  dummy_frame = xmalloc (sizeof (struct dummy_frame));
+  dummy_frame->pc   = read_register (PC_REGNUM);
+  dummy_frame->sp   = read_register (SP_REGNUM);
+  dummy_frame->fp   = fp;
+  read_register_bytes (0, dummy_frame->regs, REGISTER_BYTES);
+  dummy_frame->next = dummy_frame_stack;
+  dummy_frame_stack = dummy_frame;
+}
+
+/* Function: pop_frame
+   Restore the machine state from either the saved dummy stack or a
+   real stack frame. */
+
+void
+generic_pop_current_frame (pop)
+  void (*pop) PARAMS ((struct frame_info *frame));
+{
+  struct frame_info *frame = get_current_frame ();
+  if (PC_IN_CALL_DUMMY(frame->pc, frame->frame, frame->frame))
+    generic_pop_dummy_frame ();
+  else
+    pop (frame);
+}
+
+/* Function: pop_dummy_frame
+   Restore the machine state from a saved dummy stack frame. */
+
+void
+generic_pop_dummy_frame ()
+{
+  struct dummy_frame *dummy_frame = dummy_frame_stack;
+
+  /* FIXME: what if the first frame isn't the right one, eg..
+     because one call-by-hand function has done a longjmp into another one? */
+
+  if (!dummy_frame)
+    error ("Can't pop dummy frame!");
+  dummy_frame_stack = dummy_frame->next;
+  write_register_bytes (0, dummy_frame->regs, REGISTER_BYTES);
+  flush_cached_frames ();
+  free (dummy_frame);
+}
+
+/* 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_frame_chain_valid (fp, fi)
+     CORE_ADDR fp;
+     struct frame_info *fi;
+{
+  if (PC_IN_CALL_DUMMY(FRAME_SAVED_PC(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 (fi->frame, fp) || fi->frame == fp)
+	    && !inside_entry_file (FRAME_SAVED_PC(fi)));
+}
+ 
+/* Function: get_saved_register
+   Find register number REGNUM relative to FRAME and put its (raw,
+   target format) contents in *RAW_BUFFER.  
+
+   Set *OPTIMIZED if the variable was optimized out (and thus can't be
+   fetched).  Note that this is never set to anything other than zero
+   in this implementation.
+
+   Set *LVAL to lval_memory, lval_register, or not_lval, depending on
+   whether the value was fetched from memory, from a register, or in a
+   strange and non-modifiable way (e.g. a frame pointer which was
+   calculated rather than fetched).  We will use not_lval for values
+   fetched from generic dummy frames.
+
+   Set *ADDRP to the address, either in memory on as a REGISTER_BYTE
+   offset into the registers array.  If the value is stored in a dummy
+   frame, set *ADDRP to zero.
+
+   To use this implementation, define a function called
+   "get_saved_register" in your target code, which simply passes all
+   of its arguments to this function.
+
+   The argument RAW_BUFFER must point to aligned memory.  */
+
+void
+generic_get_saved_register (raw_buffer, optimized, addrp, frame, regnum, lval)
+     char *raw_buffer;
+     int *optimized;
+     CORE_ADDR *addrp;
+     struct frame_info *frame;
+     int regnum;
+     enum lval_type *lval;
+{
+  if (!target_has_registers)
+    error ("No registers.");
+
+  /* Normal systems don't optimize out things with register numbers.  */
+  if (optimized != NULL)
+    *optimized = 0;
+
+  if (addrp)		/* default assumption: not found in memory */
+    *addrp = 0;
+
+  /* Note: since the current frame's registers could only have been
+     saved by frames INTERIOR TO the current frame, we skip examining
+     the current frame itself: otherwise, we would be getting the
+     previous frame's registers which were saved by the current frame.  */
+
+  while (frame && ((frame = frame->next) != NULL))
+    {
+      if (PC_IN_CALL_DUMMY (frame->pc, frame->frame, frame->frame))
+	{
+	  if (lval)			/* found it in a CALL_DUMMY frame */
+	    *lval = not_lval;
+	  if (raw_buffer)
+	    memcpy (raw_buffer, 
+		    generic_find_dummy_frame (frame->pc, frame->frame) + 
+		    REGISTER_BYTE (regnum),
+		    REGISTER_RAW_SIZE (regnum));
+	      return;
+	}
+
+      FRAME_INIT_SAVED_REGS (frame);
+      if (frame->saved_regs != NULL
+	  && frame->saved_regs[regnum] != 0)
+	{
+	  if (lval)			/* found it saved on the stack */
+	    *lval = lval_memory;
+	  if (regnum == SP_REGNUM)
+	    {
+	      if (raw_buffer)		/* SP register treated specially */
+		store_address (raw_buffer, REGISTER_RAW_SIZE (regnum), 
+			       frame->saved_regs[regnum]);
+	    }
+	  else
+	    {
+	      if (addrp)		/* any other register */
+		*addrp = frame->saved_regs[regnum];
+	      if (raw_buffer)
+		read_memory (frame->saved_regs[regnum], raw_buffer, 
+			     REGISTER_RAW_SIZE (regnum));
+	    }
+	  return;
+	}
+    }
+
+  /* If we get thru the loop to this point, it means the register was
+     not saved in any frame.  Return the actual live-register value.  */
+
+  if (lval)				/* found it in a live register */
+    *lval = lval_register;
+  if (addrp)
+    *addrp = REGISTER_BYTE (regnum);
+  if (raw_buffer)
+    read_register_gen (regnum, raw_buffer);
+}
+#endif /* USE_GENERIC_DUMMY_FRAMES */
+
+void
+_initialize_blockframe ()
+{
+  obstack_init (&frame_cache_obstack);
+}