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/* Get info from stack frames; convert between frames, blocks,
functions and pc values.
Copyright (C) 1986-2018 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 3 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, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
#include "symtab.h"
#include "bfd.h"
#include "objfiles.h"
#include "frame.h"
#include "gdbcore.h"
#include "value.h"
#include "target.h"
#include "inferior.h"
#include "annotate.h"
#include "regcache.h"
#include "dummy-frame.h"
#include "command.h"
#include "gdbcmd.h"
#include "block.h"
#include "inline-frame.h"
/* 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. */
const struct block *
get_frame_block (struct frame_info *frame, CORE_ADDR *addr_in_block)
{
CORE_ADDR pc;
const struct block *bl;
int inline_count;
if (!get_frame_address_in_block_if_available (frame, &pc))
return NULL;
if (addr_in_block)
*addr_in_block = pc;
bl = block_for_pc (pc);
if (bl == NULL)
return NULL;
inline_count = frame_inlined_callees (frame);
while (inline_count > 0)
{
if (block_inlined_p (bl))
inline_count--;
bl = BLOCK_SUPERBLOCK (bl);
gdb_assert (bl != NULL);
}
return bl;
}
CORE_ADDR
get_pc_function_start (CORE_ADDR pc)
{
const struct block *bl;
struct bound_minimal_symbol msymbol;
bl = block_for_pc (pc);
if (bl)
{
struct symbol *symbol = block_linkage_function (bl);
if (symbol)
{
bl = SYMBOL_BLOCK_VALUE (symbol);
return BLOCK_ENTRY_PC (bl);
}
}
msymbol = lookup_minimal_symbol_by_pc (pc);
if (msymbol.minsym)
{
CORE_ADDR fstart = BMSYMBOL_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)
{
const struct block *bl = get_frame_block (frame, 0);
if (bl == NULL)
return NULL;
while (BLOCK_FUNCTION (bl) == NULL && BLOCK_SUPERBLOCK (bl) != NULL)
bl = BLOCK_SUPERBLOCK (bl);
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 obj_section *section)
{
const struct block *b = block_for_pc_sect (pc, section);
if (b == 0)
return 0;
return block_linkage_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));
}
/* See symtab.h. */
struct symbol *
find_pc_sect_containing_function (CORE_ADDR pc, struct obj_section *section)
{
const block *bl = block_for_pc_sect (pc, section);
if (bl == nullptr)
return nullptr;
return block_containing_function (bl);
}
/* These variables are used to cache the most recent result of
find_pc_partial_function.
The addresses cache_pc_function_low and cache_pc_function_high
record the range in which PC was found during the most recent
successful lookup. When the function occupies a single contiguous
address range, these values correspond to the low and high
addresses of the function. (The high address is actually one byte
beyond the last byte of the function.) For a function with more
than one (non-contiguous) range, the range in which PC was found is
used to set the cache bounds.
When determining whether or not these cached values apply to a
particular PC value, PC must be within the range specified by
cache_pc_function_low and cache_pc_function_high. In addition to
PC being in that range, cache_pc_section must also match PC's
section. See find_pc_partial_function() for details on both the
comparison as well as how PC's section is determined.
The other values aren't used for determining whether the cache
applies, but are used for setting the outputs from
find_pc_partial_function. cache_pc_function_low and
cache_pc_function_high are used to set outputs as well. */
static CORE_ADDR cache_pc_function_low = 0;
static CORE_ADDR cache_pc_function_high = 0;
static const char *cache_pc_function_name = 0;
static struct obj_section *cache_pc_function_section = NULL;
static const struct block *cache_pc_function_block = nullptr;
/* 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;
cache_pc_function_block = nullptr;
}
/* See symtab.h. */
int
find_pc_partial_function (CORE_ADDR pc, const char **name, CORE_ADDR *address,
CORE_ADDR *endaddr, const struct block **block)
{
struct obj_section *section;
struct symbol *f;
struct bound_minimal_symbol msymbol;
struct compunit_symtab *compunit_symtab = NULL;
struct objfile *objfile;
CORE_ADDR mapped_pc;
/* 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). */
section = find_pc_overlay (pc);
if (section == NULL)
section = find_pc_section (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;
msymbol = lookup_minimal_symbol_by_pc_section (mapped_pc, section);
ALL_OBJFILES (objfile)
{
if (objfile->sf)
{
compunit_symtab
= objfile->sf->qf->find_pc_sect_compunit_symtab (objfile, msymbol,
mapped_pc, section,
0);
}
if (compunit_symtab != NULL)
break;
}
if (compunit_symtab != NULL)
{
/* Checking whether the msymbol has a larger value is for the
"pathological" case mentioned in stack.c:find_frame_funname.
We use BLOCK_ENTRY_PC instead of BLOCK_START_PC for this
comparison because the minimal symbol should refer to the
function's entry pc which is not necessarily the lowest
address of the function. This will happen when the function
has more than one range and the entry pc is not within the
lowest range of addresses. */
f = find_pc_sect_function (mapped_pc, section);
if (f != NULL
&& (msymbol.minsym == NULL
|| (BLOCK_ENTRY_PC (SYMBOL_BLOCK_VALUE (f))
>= BMSYMBOL_VALUE_ADDRESS (msymbol))))
{
const struct block *b = SYMBOL_BLOCK_VALUE (f);
cache_pc_function_name = SYMBOL_LINKAGE_NAME (f);
cache_pc_function_section = section;
cache_pc_function_block = b;
/* For blocks occupying contiguous addresses (i.e. no gaps),
the low and high cache addresses are simply the start
and end of the block.
For blocks with non-contiguous ranges, we have to search
for the range containing mapped_pc and then use the start
and end of that range.
This causes the returned *ADDRESS and *ENDADDR values to
be limited to the range in which mapped_pc is found. See
comment preceding declaration of find_pc_partial_function
in symtab.h for more information. */
if (BLOCK_CONTIGUOUS_P (b))
{
cache_pc_function_low = BLOCK_START (b);
cache_pc_function_high = BLOCK_END (b);
}
else
{
int i;
for (i = 0; i < BLOCK_NRANGES (b); i++)
{
if (BLOCK_RANGE_START (b, i) <= mapped_pc
&& mapped_pc < BLOCK_RANGE_END (b, i))
{
cache_pc_function_low = BLOCK_RANGE_START (b, i);
cache_pc_function_high = BLOCK_RANGE_END (b, i);
break;
}
}
/* Above loop should exit via the break. */
gdb_assert (i < BLOCK_NRANGES (b));
}
goto return_cached_value;
}
}
/* 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. */
if (!section)
msymbol.minsym = NULL;
/* Must be in the minimal symbol table. */
if (msymbol.minsym == 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 = BMSYMBOL_VALUE_ADDRESS (msymbol);
cache_pc_function_name = MSYMBOL_LINKAGE_NAME (msymbol.minsym);
cache_pc_function_section = section;
cache_pc_function_high = minimal_symbol_upper_bound (msymbol);
cache_pc_function_block = nullptr;
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;
}
if (block != nullptr)
*block = cache_pc_function_block;
return 1;
}
/* See symtab.h. */
bool
find_function_entry_range_from_pc (CORE_ADDR pc, const char **name,
CORE_ADDR *address, CORE_ADDR *endaddr)
{
const struct block *block;
bool status = find_pc_partial_function (pc, name, address, endaddr, &block);
if (status && block != nullptr && !BLOCK_CONTIGUOUS_P (block))
{
CORE_ADDR entry_pc = BLOCK_ENTRY_PC (block);
for (int i = 0; i < BLOCK_NRANGES (block); i++)
{
if (BLOCK_RANGE_START (block, i) <= entry_pc
&& entry_pc < BLOCK_RANGE_END (block, i))
{
if (address != nullptr)
*address = BLOCK_RANGE_START (block, i);
if (endaddr != nullptr)
*endaddr = BLOCK_RANGE_END (block, i);
return status;
}
}
/* It's an internal error if we exit the above loop without finding
the range. */
internal_error (__FILE__, __LINE__,
_("Entry block not found in find_function_entry_range_from_pc"));
}
return status;
}
/* See symtab.h. */
struct type *
find_function_type (CORE_ADDR pc)
{
struct symbol *sym = find_pc_function (pc);
if (sym != NULL && BLOCK_ENTRY_PC (SYMBOL_BLOCK_VALUE (sym)) == pc)
return SYMBOL_TYPE (sym);
return NULL;
}
/* See symtab.h. */
struct type *
find_gnu_ifunc_target_type (CORE_ADDR resolver_funaddr)
{
struct type *resolver_type = find_function_type (resolver_funaddr);
if (resolver_type != NULL)
{
/* Get the return type of the resolver. */
struct type *resolver_ret_type
= check_typedef (TYPE_TARGET_TYPE (resolver_type));
/* If we found a pointer to function, then the resolved type
is the type of the pointed-to function. */
if (TYPE_CODE (resolver_ret_type) == TYPE_CODE_PTR)
{
struct type *resolved_type
= TYPE_TARGET_TYPE (resolver_ret_type);
if (TYPE_CODE (check_typedef (resolved_type)) == TYPE_CODE_FUNC)
return resolved_type;
}
}
return NULL;
}
/* Return the innermost stack frame that is executing inside of BLOCK and is
at least as old as the selected frame. Return NULL if there is no
such frame. If BLOCK is NULL, just return NULL. */
struct frame_info *
block_innermost_frame (const struct block *block)
{
struct frame_info *frame;
if (block == NULL)
return NULL;
frame = get_selected_frame_if_set ();
if (frame == NULL)
frame = get_current_frame ();
while (frame != NULL)
{
const struct block *frame_block = get_frame_block (frame, NULL);
if (frame_block != NULL && contained_in (frame_block, block))
return frame;
frame = get_prev_frame (frame);
}
return NULL;
}
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