371 lines
11 KiB
C
371 lines
11 KiB
C
/* Get info from stack frames; convert between frames, blocks,
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functions and pc values.
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Copyright (C) 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995,
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1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2007, 2008
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Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#include "defs.h"
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#include "symtab.h"
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#include "bfd.h"
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#include "objfiles.h"
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#include "frame.h"
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#include "gdbcore.h"
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#include "value.h"
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#include "target.h"
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#include "inferior.h"
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#include "annotate.h"
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#include "regcache.h"
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#include "gdb_assert.h"
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#include "dummy-frame.h"
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#include "command.h"
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#include "gdbcmd.h"
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#include "block.h"
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/* Prototypes for exported functions. */
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void _initialize_blockframe (void);
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/* Return the innermost lexical block in execution
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in a specified stack frame. The frame address is assumed valid.
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If ADDR_IN_BLOCK is non-zero, set *ADDR_IN_BLOCK to the exact code
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address we used to choose the block. We use this to find a source
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line, to decide which macro definitions are in scope.
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The value returned in *ADDR_IN_BLOCK isn't necessarily the frame's
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PC, and may not really be a valid PC at all. For example, in the
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caller of a function declared to never return, the code at the
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return address will never be reached, so the call instruction may
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be the very last instruction in the block. So the address we use
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to choose the block is actually one byte before the return address
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--- hopefully pointing us at the call instruction, or its delay
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slot instruction. */
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struct block *
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get_frame_block (struct frame_info *frame, CORE_ADDR *addr_in_block)
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{
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const CORE_ADDR pc = get_frame_address_in_block (frame);
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if (addr_in_block)
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*addr_in_block = pc;
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return block_for_pc (pc);
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}
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CORE_ADDR
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get_pc_function_start (CORE_ADDR pc)
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{
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struct block *bl;
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struct minimal_symbol *msymbol;
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bl = block_for_pc (pc);
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if (bl)
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{
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struct symbol *symbol = block_linkage_function (bl);
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if (symbol)
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{
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bl = SYMBOL_BLOCK_VALUE (symbol);
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return BLOCK_START (bl);
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}
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}
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msymbol = lookup_minimal_symbol_by_pc (pc);
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if (msymbol)
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{
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CORE_ADDR fstart = SYMBOL_VALUE_ADDRESS (msymbol);
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if (find_pc_section (fstart))
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return fstart;
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}
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return 0;
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}
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/* Return the symbol for the function executing in frame FRAME. */
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struct symbol *
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get_frame_function (struct frame_info *frame)
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{
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struct block *bl = get_frame_block (frame, 0);
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if (bl == 0)
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return 0;
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return block_linkage_function (bl);
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}
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/* Return the function containing pc value PC in section SECTION.
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Returns 0 if function is not known. */
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struct symbol *
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find_pc_sect_function (CORE_ADDR pc, struct bfd_section *section)
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{
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struct block *b = block_for_pc_sect (pc, section);
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if (b == 0)
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return 0;
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return block_linkage_function (b);
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}
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/* Return the function containing pc value PC.
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Returns 0 if function is not known. Backward compatibility, no section */
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struct symbol *
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find_pc_function (CORE_ADDR pc)
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{
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return find_pc_sect_function (pc, find_pc_mapped_section (pc));
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}
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/* These variables are used to cache the most recent result
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* of find_pc_partial_function. */
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static CORE_ADDR cache_pc_function_low = 0;
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static CORE_ADDR cache_pc_function_high = 0;
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static char *cache_pc_function_name = 0;
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static struct bfd_section *cache_pc_function_section = NULL;
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/* Clear cache, e.g. when symbol table is discarded. */
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void
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clear_pc_function_cache (void)
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{
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cache_pc_function_low = 0;
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cache_pc_function_high = 0;
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cache_pc_function_name = (char *) 0;
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cache_pc_function_section = NULL;
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}
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/* Finds the "function" (text symbol) that is smaller than PC but
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greatest of all of the potential text symbols in SECTION. Sets
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*NAME and/or *ADDRESS conditionally if that pointer is non-null.
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If ENDADDR is non-null, then set *ENDADDR to be the end of the
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function (exclusive), but passing ENDADDR as non-null means that
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the function might cause symbols to be read. This function either
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succeeds or fails (not halfway succeeds). If it succeeds, it sets
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*NAME, *ADDRESS, and *ENDADDR to real information and returns 1.
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If it fails, it sets *NAME, *ADDRESS, and *ENDADDR to zero and
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returns 0. */
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/* Backward compatibility, no section argument. */
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int
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find_pc_partial_function (CORE_ADDR pc, char **name, CORE_ADDR *address,
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CORE_ADDR *endaddr)
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{
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struct bfd_section *section;
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struct partial_symtab *pst;
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struct symbol *f;
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struct minimal_symbol *msymbol;
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struct partial_symbol *psb;
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struct obj_section *osect;
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int i;
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CORE_ADDR mapped_pc;
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/* To ensure that the symbol returned belongs to the correct setion
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(and that the last [random] symbol from the previous section
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isn't returned) try to find the section containing PC. First try
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the overlay code (which by default returns NULL); and second try
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the normal section code (which almost always succeeds). */
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section = find_pc_overlay (pc);
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if (section == NULL)
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{
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struct obj_section *obj_section = find_pc_section (pc);
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if (obj_section == NULL)
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section = NULL;
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else
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section = obj_section->the_bfd_section;
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}
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mapped_pc = overlay_mapped_address (pc, section);
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if (mapped_pc >= cache_pc_function_low
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&& mapped_pc < cache_pc_function_high
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&& section == cache_pc_function_section)
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goto return_cached_value;
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msymbol = lookup_minimal_symbol_by_pc_section (mapped_pc, section);
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pst = find_pc_sect_psymtab (mapped_pc, section);
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if (pst)
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{
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/* Need to read the symbols to get a good value for the end address. */
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if (endaddr != NULL && !pst->readin)
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{
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/* Need to get the terminal in case symbol-reading produces
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output. */
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target_terminal_ours_for_output ();
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PSYMTAB_TO_SYMTAB (pst);
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}
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if (pst->readin)
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{
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/* Checking whether the msymbol has a larger value is for the
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"pathological" case mentioned in print_frame_info. */
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f = find_pc_sect_function (mapped_pc, section);
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if (f != NULL
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&& (msymbol == NULL
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|| (BLOCK_START (SYMBOL_BLOCK_VALUE (f))
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>= SYMBOL_VALUE_ADDRESS (msymbol))))
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{
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cache_pc_function_low = BLOCK_START (SYMBOL_BLOCK_VALUE (f));
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cache_pc_function_high = BLOCK_END (SYMBOL_BLOCK_VALUE (f));
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cache_pc_function_name = DEPRECATED_SYMBOL_NAME (f);
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cache_pc_function_section = section;
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goto return_cached_value;
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}
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}
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else
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{
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/* Now that static symbols go in the minimal symbol table, perhaps
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we could just ignore the partial symbols. But at least for now
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we use the partial or minimal symbol, whichever is larger. */
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psb = find_pc_sect_psymbol (pst, mapped_pc, section);
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if (psb
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&& (msymbol == NULL ||
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(SYMBOL_VALUE_ADDRESS (psb)
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>= SYMBOL_VALUE_ADDRESS (msymbol))))
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{
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/* This case isn't being cached currently. */
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if (address)
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*address = SYMBOL_VALUE_ADDRESS (psb);
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if (name)
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*name = DEPRECATED_SYMBOL_NAME (psb);
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/* endaddr non-NULL can't happen here. */
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return 1;
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}
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}
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}
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/* Not in the normal symbol tables, see if the pc is in a known section.
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If it's not, then give up. This ensures that anything beyond the end
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of the text seg doesn't appear to be part of the last function in the
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text segment. */
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osect = find_pc_sect_section (mapped_pc, section);
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if (!osect)
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msymbol = NULL;
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/* Must be in the minimal symbol table. */
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if (msymbol == NULL)
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{
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/* No available symbol. */
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if (name != NULL)
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*name = 0;
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if (address != NULL)
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*address = 0;
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if (endaddr != NULL)
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*endaddr = 0;
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return 0;
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}
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cache_pc_function_low = SYMBOL_VALUE_ADDRESS (msymbol);
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cache_pc_function_name = DEPRECATED_SYMBOL_NAME (msymbol);
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cache_pc_function_section = section;
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/* If the minimal symbol has a size, use it for the cache.
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Otherwise use the lesser of the next minimal symbol in the same
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section, or the end of the section, as the end of the
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function. */
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if (MSYMBOL_SIZE (msymbol) != 0)
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cache_pc_function_high = cache_pc_function_low + MSYMBOL_SIZE (msymbol);
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else
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{
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/* Step over other symbols at this same address, and symbols in
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other sections, to find the next symbol in this section with
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a different address. */
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for (i = 1; DEPRECATED_SYMBOL_NAME (msymbol + i) != NULL; i++)
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{
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if (SYMBOL_VALUE_ADDRESS (msymbol + i) != SYMBOL_VALUE_ADDRESS (msymbol)
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&& SYMBOL_BFD_SECTION (msymbol + i) == SYMBOL_BFD_SECTION (msymbol))
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break;
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}
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if (DEPRECATED_SYMBOL_NAME (msymbol + i) != NULL
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&& SYMBOL_VALUE_ADDRESS (msymbol + i) < osect->endaddr)
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cache_pc_function_high = SYMBOL_VALUE_ADDRESS (msymbol + i);
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else
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/* We got the start address from the last msymbol in the objfile.
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So the end address is the end of the section. */
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cache_pc_function_high = osect->endaddr;
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}
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return_cached_value:
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if (address)
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{
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if (pc_in_unmapped_range (pc, section))
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*address = overlay_unmapped_address (cache_pc_function_low, section);
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else
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*address = cache_pc_function_low;
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}
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if (name)
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*name = cache_pc_function_name;
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if (endaddr)
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{
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if (pc_in_unmapped_range (pc, section))
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{
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/* Because the high address is actually beyond the end of
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the function (and therefore possibly beyond the end of
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the overlay), we must actually convert (high - 1) and
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then add one to that. */
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*endaddr = 1 + overlay_unmapped_address (cache_pc_function_high - 1,
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section);
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}
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else
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*endaddr = cache_pc_function_high;
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}
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return 1;
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}
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/* Return the innermost stack frame executing inside of BLOCK,
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or NULL if there is no such frame. If BLOCK is NULL, just return NULL. */
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struct frame_info *
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block_innermost_frame (struct block *block)
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{
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struct frame_info *frame;
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CORE_ADDR start;
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CORE_ADDR end;
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CORE_ADDR calling_pc;
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if (block == NULL)
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return NULL;
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start = BLOCK_START (block);
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end = BLOCK_END (block);
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frame = get_current_frame ();
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while (frame != NULL)
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{
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calling_pc = get_frame_address_in_block (frame);
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if (calling_pc >= start && calling_pc < end)
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return frame;
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frame = get_prev_frame (frame);
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}
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return NULL;
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}
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