/* Get info from stack frames;
convert between frames, blocks, functions and pc values.
- Copyright (C) 1986, 1987, 1988 Free Software Foundation, Inc.
+ Copyright (C) 1986, 1987, 1988, 1989 Free Software Foundation, Inc.
-GDB is distributed in the hope that it will be useful, but WITHOUT ANY
-WARRANTY. No author or distributor accepts responsibility to anyone
-for the consequences of using it or for whether it serves any
-particular purpose or works at all, unless he says so in writing.
-Refer to the GDB General Public License for full details.
+This file is part of GDB.
-Everyone is granted permission to copy, modify and redistribute GDB,
-but only under the conditions described in the GDB General Public
-License. A copy of this license is supposed to have been given to you
-along with GDB so you can know your rights and responsibilities. It
-should be in a file named COPYING. Among other things, the copyright
-notice and this notice must be preserved on all copies.
+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.
-In other words, go ahead and share GDB, but don't try to stop
-anyone else from sharing it farther. Help stamp out software hoarding!
-*/
+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., 675 Mass Ave, Cambridge, MA 02139, USA. */
+
+#include <stdio.h>
#include "defs.h"
-#include "initialize.h"
#include "param.h"
#include "symtab.h"
#include "frame.h"
+#include "gdbcore.h"
+#include "value.h" /* for read_register */
+#include "target.h" /* for target_has_stack */
+
+CORE_ADDR read_pc (); /* In infcmd.c */
-/* Address of end of first object file.
+/* Start and end of object file containing the entry point.
+ STARTUP_FILE_END is the first address of the next file.
This file is assumed to be a startup file
and frames with pc's inside it
- are treated as nonexistent. */
+ are treated as nonexistent.
+
+ Setting these variables is necessary so that backtraces do not fly off
+ the bottom of the stack. */
+CORE_ADDR startup_file_start;
+CORE_ADDR startup_file_end;
+
+/* Is ADDR outside 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. */
+int
+outside_startup_file (addr)
+ CORE_ADDR addr;
+{
+ return !(addr >= startup_file_start && addr < startup_file_end);
+}
+
+/* Support an alternate method to avoid running off the bottom of
+ the stack (or top, depending upon your stack orientation).
+
+ There are two frames that are "special", the frame for the function
+ containing the process entry point, since it has no predecessor frame,
+ and the frame for the function containing the user code entry point
+ (the main() function), since all the predecessor frames are for the
+ process startup code. Since we have no guarantee that the linked
+ in startup modules have any debugging information that gdb can use,
+ we need to avoid following frame pointers back into frames that might
+ have been built in the startup code, as we might get hopelessly
+ confused. However, we almost always have debugging information
+ available for main().
+
+ These variables are used to save the range of PC values which are valid
+ within the main() function and within the function containing the process
+ entry point. If we always consider the frame for main() as the outermost
+ frame when debugging user code, and the frame for the process entry
+ point function as the outermost frame when debugging startup code, then
+ all we have to do is have FRAME_CHAIN_VALID return false whenever a
+ frame's current PC is within the range specified by these variables.
+ In essence, we set "blocks" in the frame chain beyond which we will
+ not proceed when following the frame chain.
+
+ A nice side effect is that we can still debug startup code without
+ running off the end of the frame chain, assuming that we have usable
+ debugging information in the startup modules, and if we choose to not
+ use the block at main, or can't find it for some reason, everything
+ still works as before. And if we have no startup code debugging
+ information but we do have usable information for main(), backtraces
+ from user code don't go wandering off into the startup code.
+
+ To use this method, define your FRAME_CHAIN_VALID macro like:
+
+ #define FRAME_CHAIN_VALID(chain, thisframe) \
+ (chain != 0 \
+ && !(inside_main_scope ((thisframe)->pc)) \
+ && !(inside_entry_scope ((thisframe)->pc)))
+
+ and add initializations of the four scope controlling variables inside
+ the object file / debugging information processing modules. */
+
+CORE_ADDR entry_scope_lowpc;
+CORE_ADDR entry_scope_highpc;
+CORE_ADDR main_scope_lowpc;
+CORE_ADDR main_scope_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. */
+
+int
+inside_main_scope (pc)
+CORE_ADDR pc;
+{
+ return (main_scope_lowpc <= pc && pc < main_scope_highpc);
+}
+
+/* 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 above
+ for why we might want to do this.
+
+ Typically called from FRAME_CHAIN_VALID. */
-CORE_ADDR first_object_file_end;
+int
+inside_entry_scope (pc)
+CORE_ADDR pc;
+{
+ return (entry_scope_lowpc <= pc && pc < entry_scope_highpc);
+}
/* Address of innermost stack frame (contents of FP register) */
static FRAME current_frame;
-struct block *block_for_pc ();
-CORE_ADDR get_pc_function_start ();
-
-START_FILE
+/*
+ * 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.
+ */
+struct obstack frame_cache_obstack;
/* Return the innermost (currently executing) stack frame. */
current_frame = frame;
}
+FRAME
+create_new_frame (addr, pc)
+ FRAME_ADDR addr;
+ CORE_ADDR pc;
+{
+ struct frame_info *fci; /* Same type as FRAME */
+
+ fci = (struct frame_info *)
+ obstack_alloc (&frame_cache_obstack,
+ sizeof (struct frame_info));
+
+ /* Arbitrary frame */
+ fci->next = (struct frame_info *) 0;
+ fci->prev = (struct frame_info *) 0;
+ fci->frame = addr;
+ fci->next_frame = 0; /* Since arbitrary */
+ fci->pc = pc;
+
+#ifdef INIT_EXTRA_FRAME_INFO
+ INIT_EXTRA_FRAME_INFO (0, fci);
+#endif
+
+ return fci;
+}
+
/* Return the frame that called FRAME.
If FRAME is the original frame (it has no caller), return 0. */
get_prev_frame (frame)
FRAME frame;
{
- CORE_ADDR pointer;
- /* The caller of "no frame" is the innermost frame. */
- if (frame == 0)
- return get_current_frame ();
-
- /* Two macros defined in param.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. */
- pointer = FRAME_CHAIN (frame);
- if (!FRAME_CHAIN_VALID (pointer, frame))
- return 0;
- /* If frame has a caller, combine the chain pointer and the frame's own
- address to get the address of the caller. */
- return FRAME_CHAIN_COMBINE (pointer, frame);
+ /* We're allowed to know that FRAME and "struct frame_info *" are
+ the same */
+ return get_prev_frame_info (frame);
+}
+
+/* Return the frame that FRAME calls (0 if FRAME is the innermost
+ frame). */
+
+FRAME
+get_next_frame (frame)
+ FRAME frame;
+{
+ /* We're allowed to know that FRAME and "struct frame_info *" are
+ the same */
+ 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 = (struct frame_info *) 0; /* Invalidate cache */
+}
+
+/* Flush the frame cache, and start a new one if necessary. */
+void
+reinit_frame_cache ()
+{
+ FRAME fr = current_frame;
+ flush_cached_frames ();
+ if (fr)
+ set_current_frame ( create_new_frame (read_register (FP_REGNUM),
+ read_pc ()));
}
/* Return a structure containing various interesting information
about a specified stack frame. */
+/* How do I justify including this function? Well, the FRAME
+ identifier format has gone through several changes recently, and
+ it's not completely inconceivable that it could happen again. If
+ it does, have this routine around will help */
-struct frame_info
+struct frame_info *
get_frame_info (frame)
FRAME frame;
{
- struct frame_info val;
- FRAME current = get_current_frame ();
- register FRAME frame1;
+ return frame;
+}
- val.frame = frame;
+/* 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. */
- if (frame == current)
+/* Return nonzero if the function for this frame has a prologue. Many
+ machines can define FRAMELESS_FUNCTION_INVOCATION to just call this
+ function. */
+
+int
+frameless_look_for_prologue (frame)
+ FRAME frame;
+{
+ CORE_ADDR func_start, after_prologue;
+ func_start = (get_pc_function_start (frame->pc) +
+ FUNCTION_START_OFFSET);
+ if (func_start)
{
- val.pc = read_pc ();
- val.next_frame = 0;
+ 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
- {
- for (frame1 = current; frame1; frame1 = get_prev_frame (frame1))
- {
- QUIT;
- if (frame1 == frame)
- break;
+ 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;
+}
- val.pc = FRAME_SAVED_PC (frame1);
- val.next_frame = frame1;
- }
- }
+/* Default a few macros that people seldom redefine. */
- return val;
-}
+#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
-/* Return a structure containing various interesting information
- about the frame that called FRAME.
+#ifndef FRAME_CHAIN_COMBINE
+#define FRAME_CHAIN_COMBINE(chain, thisframe) (chain)
+#endif
- This is much faster than get_frame_info (get_prev_frame (FRAME))
- because it does not need to search the entire stack
- to find the frame called by the one being described -- that is FRAME. */
+/* 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
+struct frame_info *
get_prev_frame_info (next_frame)
FRAME next_frame;
{
- struct frame_info val;
- register FRAME frame = get_prev_frame (next_frame);
+ FRAME_ADDR address;
+ struct frame_info *prev;
+ int fromleaf = 0;
- val.frame = frame;
- val.next_frame = next_frame;
+ /* 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 == 0)
+ if (!next_frame)
{
- val.pc = read_pc ();
+ if (!current_frame)
+ {
+ error ("You haven't set up a process's stack to examine.");
+ }
+
+ return current_frame;
}
- else
+
+ /* 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))
{
- val.pc = FRAME_SAVED_PC (next_frame);
+ FRAMELESS_FUNCTION_INVOCATION (next_frame, fromleaf);
+ if (fromleaf)
+ address = next_frame->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));
+
+ if (next_frame)
+ next_frame->prev = prev;
+ prev->next = next_frame;
+ prev->prev = (struct frame_info *) 0;
+ prev->frame = address;
+ prev->next_frame = prev->next ? prev->next->frame : 0;
+
+#ifdef INIT_EXTRA_FRAME_INFO
+ INIT_EXTRA_FRAME_INFO(fromleaf, prev);
+#endif
- return val;
+ /* This entry is in the frame queue now, which is good since
+ FRAME_SAVED_PC may use that queue to figure out it's value
+ (see tm-sparc.h). We want the pc saved in the inferior frame. */
+ INIT_FRAME_PC(fromleaf, prev);
+
+ return prev;
}
CORE_ADDR
get_frame_pc (frame)
FRAME frame;
{
- struct frame_info fi;
+ struct frame_info *fi;
fi = get_frame_info (frame);
- return fi.pc;
+ return fi->pc;
}
+#if defined (FRAME_FIND_SAVED_REGS)
/* Find the addresses in which registers are saved in FRAME. */
void
struct frame_info *frame_info_addr;
struct frame_saved_regs *saved_regs_addr;
{
- FRAME_FIND_SAVED_REGS (*frame_info_addr, *saved_regs_addr);
+ FRAME_FIND_SAVED_REGS (frame_info_addr, *saved_regs_addr);
}
+#endif
/* Return the innermost lexical block in execution
in a specified stack frame. The frame address is assumed valid. */
get_frame_block (frame)
FRAME frame;
{
- struct frame_info fi;
+ struct frame_info *fi;
+ CORE_ADDR pc;
fi = get_frame_info (frame);
- return block_for_pc (fi.pc);
+
+ pc = fi->pc;
+ if (fi->next_frame != 0)
+ /* We are not in the innermost frame. 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 fi->pc point after the call insn anyway. */
+ --pc;
+ return block_for_pc (pc);
}
struct block *
{
register struct block *bl = block_for_pc (pc);
register struct symbol *symbol;
- if (bl == 0)
+ if (bl == 0 || (symbol = block_function (bl)) == 0)
{
register int misc_index = find_pc_misc_function (pc);
if (misc_index >= 0)
return misc_function_vector[misc_index].address;
return 0;
}
- symbol = block_function (bl);
bl = SYMBOL_BLOCK_VALUE (symbol);
return BLOCK_START (bl);
-}
+}
/* Return the symbol for the function executing in frame FRAME. */
return block_function (bl);
}
\f
-/* Return the innermost lexical block containing the specified pc value,
- or 0 if there is none. */
+/* Return the blockvector immediately containing the innermost lexical block
+ containing the specified pc value, 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 block *
-block_for_pc (pc)
+struct blockvector *
+blockvector_for_pc (pc, pindex)
register CORE_ADDR pc;
+ int *pindex;
{
register struct block *b;
register int bot, top, half;
struct blockvector *bl;
/* First search all symtabs for one whose file contains our pc */
-
- for (s = symtab_list; s; s = s->next)
- {
- bl = BLOCKVECTOR (s);
- b = BLOCKVECTOR_BLOCK (bl, 0);
- if (BLOCK_START (b) <= pc
- && BLOCK_END (b) > pc)
- break;
- }
-
+ s = find_pc_symtab (pc);
if (s == 0)
return 0;
+ bl = BLOCKVECTOR (s);
+ 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. */
{
b = BLOCKVECTOR_BLOCK (bl, bot);
if (BLOCK_END (b) > pc)
- return b;
+ {
+ if (pindex)
+ *pindex = bot;
+ return bl;
+ }
bot--;
}
return 0;
}
+/* Return the innermost lexical block containing the specified pc value,
+ or 0 if there is none. */
+
+struct block *
+block_for_pc (pc)
+ register CORE_ADDR pc;
+{
+ register struct blockvector *bl;
+ int index;
+
+ bl = blockvector_for_pc (pc, &index);
+ if (bl)
+ return BLOCKVECTOR_BLOCK (bl, index);
+ return 0;
+}
+
/* Return the function containing pc value PC.
Returns 0 if function is not known. */
return block_function (b);
}
+/* 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;
+
+/* 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;
+}
+
+/* Finds the "function" (text symbol) that is smaller than PC
+ but greatest of all of the potential text symbols. Sets
+ *NAME and/or *ADDRESS conditionally if that pointer is non-zero.
+ Returns 0 if it couldn't find anything, 1 if it did. On a zero
+ return, *NAME and *ADDRESS are always set to zero. On a 1 return,
+ *NAME and *ADDRESS contain real information. */
+
+int
+find_pc_partial_function (pc, name, address)
+ CORE_ADDR pc;
+ char **name;
+ CORE_ADDR *address;
+{
+ struct partial_symtab *pst;
+ struct symbol *f;
+ int miscfunc;
+ struct partial_symbol *psb;
+
+ if (pc >= cache_pc_function_low && pc < cache_pc_function_high)
+ {
+ if (address)
+ *address = cache_pc_function_low;
+ if (name)
+ *name = cache_pc_function_name;
+ return 1;
+ }
+
+ pst = find_pc_psymtab (pc);
+ if (pst)
+ {
+ if (pst->readin)
+ {
+ /* The information we want has already been read in.
+ We can go to the already readin symbols and we'll get
+ the best possible answer. */
+ f = find_pc_function (pc);
+ if (!f)
+ {
+ return_error:
+ /* No available symbol. */
+ if (name != 0)
+ *name = 0;
+ if (address != 0)
+ *address = 0;
+ return 0;
+ }
+
+ 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);
+ if (name)
+ *name = cache_pc_function_name;
+ if (address)
+ *address = cache_pc_function_low;
+ return 1;
+ }
+
+ /* Get the information from a combination of the pst
+ (static symbols), and the misc function vector (extern
+ symbols). */
+ miscfunc = find_pc_misc_function (pc);
+ psb = find_pc_psymbol (pst, pc);
+
+ if (!psb && miscfunc == -1)
+ {
+ goto return_error;
+ }
+ if (psb
+ && (miscfunc == -1
+ || (SYMBOL_VALUE_ADDRESS (psb)
+ >= misc_function_vector[miscfunc].address)))
+ {
+ /* This case isn't being cached currently. */
+ if (address)
+ *address = SYMBOL_VALUE_ADDRESS (psb);
+ if (name)
+ *name = SYMBOL_NAME (psb);
+ return 1;
+ }
+ }
+ else
+ /* Must be in the misc function stuff. */
+ {
+ miscfunc = find_pc_misc_function (pc);
+ if (miscfunc == -1)
+ goto return_error;
+ }
+
+ {
+ if (misc_function_vector[miscfunc].type == mf_text)
+ cache_pc_function_low = misc_function_vector[miscfunc].address;
+ else
+ /* It is a transfer table for Sun shared libraries. */
+ cache_pc_function_low = pc - FUNCTION_START_OFFSET;
+ }
+ cache_pc_function_name = misc_function_vector[miscfunc].name;
+ if (miscfunc < misc_function_count /* && FIXME mf_text again? */ )
+ cache_pc_function_high = misc_function_vector[miscfunc+1].address;
+ else
+ cache_pc_function_high = cache_pc_function_low + 1;
+ if (address)
+ *address = cache_pc_function_low;
+ if (name)
+ *name = cache_pc_function_name;
+ return 1;
+}
+
/* Find the misc function whose address is the largest
while being less than PC. Return its index in misc_function_vector.
Returns -1 if PC is not in suitable range. */
register int lo = 0;
register int hi = misc_function_count-1;
register int new;
- register int distance;
/* Note that the last thing in the vector is always _etext. */
+ /* Actually, "end", now that non-functions
+ go on the misc_function_vector. */
/* Above statement is not *always* true - fix for case where there are */
/* no misc functions at all (ie no symbol table has been read). */
if (hi < 0) return -1; /* no misc functions recorded */
/* trivial reject range test */
- if (pc < misc_function_vector[0].address ||
+ if (pc < misc_function_vector[0].address ||
pc > misc_function_vector[hi].address)
return -1;
+ /* Note that the following search will not return hi if
+ pc == misc_function_vector[hi].address. If "end" points to the
+ first unused location, this is correct and the above test
+ simply needs to be changed to
+ "pc >= misc_function_vector[hi].address". */
do {
new = (lo + hi) >> 1;
- distance = misc_function_vector[new].address - pc;
- if (distance == 0)
+ if (misc_function_vector[new].address == pc)
return new; /* an exact match */
- else if (distance > 0)
+ else if (misc_function_vector[new].address > pc)
hi = new;
else
lo = new;
block_innermost_frame (block)
struct block *block;
{
- struct frame_info fi;
+ struct frame_info *fi;
register FRAME frame;
register CORE_ADDR start = BLOCK_START (block);
register CORE_ADDR end = BLOCK_END (block);
frame = 0;
while (1)
{
- fi = get_prev_frame_info (frame);
- frame = fi.frame;
+ frame = get_prev_frame (frame);
if (frame == 0)
return 0;
- if (fi.pc >= start && fi.pc < end)
+ fi = get_frame_info (frame);
+ if (fi->pc >= start && fi->pc < end)
return frame;
}
}
-static
-initialize ()
+void
+_initialize_blockframe ()
{
+ obstack_init (&frame_cache_obstack);
}
-
-END_FILE
projects / deliverable / binutils-gdb.git / blobdiff