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| Current File : //usr/src/contrib/gdb/gdb/blockframe.c |
/* 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, 2003, 2004
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 "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"
#include "command.h"
#include "gdbcmd.h"
#include "block.h"
/* Prototypes for exported functions. */
void _initialize_blockframe (void);
/* 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 DEPRECATED_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
deprecated_inside_entry_file (CORE_ADDR addr)
{
if (addr == 0)
return 1;
if (symfile_objfile == 0)
return 0;
if (CALL_DUMMY_LOCATION == AT_ENTRY_POINT
|| CALL_DUMMY_LOCATION == AT_SYMBOL)
{
/* 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.deprecated_entry_file_lowpc &&
addr < symfile_objfile->ei.deprecated_entry_file_highpc);
}
/* Test whether PC is in the range of addresses that corresponds to
the "main" function. */
int
inside_main_func (CORE_ADDR pc)
{
struct minimal_symbol *msymbol;
if (symfile_objfile == 0)
return 0;
msymbol = lookup_minimal_symbol (main_name (), NULL, symfile_objfile);
/* If the address range hasn't been set up at symbol reading time,
set it up now. */
if (msymbol != NULL
&& symfile_objfile->ei.main_func_lowpc == INVALID_ENTRY_LOWPC
&& symfile_objfile->ei.main_func_highpc == INVALID_ENTRY_HIGHPC)
{
/* brobecker/2003-10-10: We used to rely on lookup_symbol() to
search the symbol associated to the "main" function.
Unfortunately, lookup_symbol() uses the current-language
la_lookup_symbol_nonlocal function to do the global symbol
search. Depending on the language, this can introduce
certain side-effects, because certain languages, for instance
Ada, may find more than one match. Therefore we prefer to
search the "main" function symbol using its address rather
than its name. */
struct symbol *mainsym =
find_pc_function (SYMBOL_VALUE_ADDRESS (msymbol));
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));
}
}
/* Not in the normal symbol tables, see if "main" is in the partial
symbol table. If it's not, then give up. */
if (msymbol != NULL && MSYMBOL_TYPE (msymbol) == mst_text)
{
CORE_ADDR maddr = SYMBOL_VALUE_ADDRESS (msymbol);
asection *msect = SYMBOL_BFD_SECTION (msymbol);
struct obj_section *osect = find_pc_sect_section (maddr, msect);
if (osect != NULL)
{
int i;
/* 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_LINKAGE_NAME (msymbol + i) != NULL; i++)
{
if (SYMBOL_VALUE_ADDRESS (msymbol + i) != maddr
&& SYMBOL_BFD_SECTION (msymbol + i) == msect)
break;
}
symfile_objfile->ei.main_func_lowpc = maddr;
/* Use the lesser of the next minimal symbol in the same
section, or the end of the section, as the end of the
function. */
if (SYMBOL_LINKAGE_NAME (msymbol + i) != NULL
&& SYMBOL_VALUE_ADDRESS (msymbol + i) < osect->endaddr)
symfile_objfile->ei.main_func_highpc =
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. */
symfile_objfile->ei.main_func_highpc = osect->endaddr;
}
}
return (symfile_objfile->ei.main_func_lowpc <= pc
&& symfile_objfile->ei.main_func_highpc > pc);
}
/* Test whether THIS_FRAME is inside the process entry point function. */
int
inside_entry_func (struct frame_info *this_frame)
{
return (get_frame_func (this_frame) == entry_point_address ());
}
/* Similar to inside_entry_func, but accomodating legacy frame code. */
static int
legacy_inside_entry_func (CORE_ADDR pc)
{
if (symfile_objfile == 0)
return 0;
if (CALL_DUMMY_LOCATION == AT_ENTRY_POINT)
{
/* Do not stop backtracing if the program counter is in the call
dummy at the entry point. */
/* FIXME: This 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 DEPRECATED_FRAMELESS_FUNCTION_INVOCATION
to just call this function. */
int
legacy_frameless_look_for_prologue (struct frame_info *frame)
{
CORE_ADDR func_start;
func_start = get_frame_func (frame);
if (func_start)
{
func_start += FUNCTION_START_OFFSET;
/* NOTE: cagney/2004-02-09: Eliminated per-architecture
PROLOGUE_FRAMELESS_P call as architectures with custom
implementations had all been deleted. Eventually even this
function can go - GDB no longer tries to differentiate
between framed, frameless and stackless functions. They are
all now considered equally evil :-^. */
/* If skipping the prologue ends up skips nothing, there must be
no prologue and hence no code creating a frame. There for
the function is "frameless" :-/. */
return func_start == SKIP_PROLOGUE (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 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 = get_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)
{
struct block *bl;
struct minimal_symbol *msymbol;
bl = block_for_pc (pc);
if (bl)
{
struct symbol *symbol = block_function (bl);
if (symbol)
{
bl = SYMBOL_BLOCK_VALUE (symbol);
return BLOCK_START (bl);
}
}
msymbol = lookup_minimal_symbol_by_pc (pc);
if (msymbol)
{
CORE_ADDR fstart = SYMBOL_VALUE_ADDRESS (msymbol);
if (find_pc_section (fstart))
return fstart;
}
return 0;
}
/* Return the symbol for the function executing in frame FRAME. */
struct symbol *
get_frame_function (struct frame_info *frame)
{
struct block *bl = get_frame_block (frame, 0);
if (bl == 0)
return 0;
return block_function (bl);
}
/* 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 bfd_section *section)
{
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 bfd_section *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 = DEPRECATED_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 = DEPRECATED_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 = DEPRECATED_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; DEPRECATED_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 (DEPRECATED_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)
{
struct bfd_section *bfd_section;
/* To ensure that the symbol returned belongs to the correct setion
(and that the last [random] symbol from the previous section
isn't returned) try to find the section containing PC. First try
the overlay code (which by default returns NULL); and second try
the normal section code (which almost always succeeds). */
bfd_section = find_pc_overlay (pc);
if (bfd_section == NULL)
{
struct obj_section *obj_section = find_pc_section (pc);
if (obj_section == NULL)
bfd_section = NULL;
else
bfd_section = obj_section->the_bfd_section;
}
return find_pc_sect_partial_function (pc, bfd_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;
CORE_ADDR start;
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 = get_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. */
/* 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 DEPRECATED_FP_REGNUM (or the saved values thereof),
respectively, are the things to pass.
This won't work on the 29k, where SP_REGNUM and
DEPRECATED_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)
{
CORE_ADDR addr = entry_point_address ();
return ((pc) >= addr && (pc) <= (addr + DECR_PC_AFTER_BREAK));
}
/* 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
legacy_frame_chain_valid (CORE_ADDR fp, struct frame_info *fi)
{
/* Don't prune CALL_DUMMY frames. */
if (DEPRECATED_USE_GENERIC_DUMMY_FRAMES
&& DEPRECATED_PC_IN_CALL_DUMMY (get_frame_pc (fi), 0, 0))
return 1;
/* If the new frame pointer is zero, then it isn't valid. */
if (fp == 0)
return 0;
/* If the new frame would be inside (younger than) the previous frame,
then it isn't valid. */
if (INNER_THAN (fp, get_frame_base (fi)))
return 0;
/* If the architecture has a custom DEPRECATED_FRAME_CHAIN_VALID,
call it now. */
if (DEPRECATED_FRAME_CHAIN_VALID_P ())
return DEPRECATED_FRAME_CHAIN_VALID (fp, fi);
/* If we're already inside the entry function for the main objfile, then it
isn't valid. */
if (legacy_inside_entry_func (get_frame_pc (fi)))
return 0;
/* If we're inside the entry file, it isn't valid. */
/* NOTE/drow 2002-12-25: should there be a way to disable this check? It
assumes a single small entry file, and the way some debug readers (e.g.
dbxread) figure out which object is the entry file is somewhat hokey. */
if (deprecated_inside_entry_file (frame_pc_unwind (fi)))
return 0;
return 1;
}