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482 lines
13 KiB
C
482 lines
13 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) 1986-2020 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 "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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#include "inline-frame.h"
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/* Return the innermost lexical block in execution in a specified
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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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const 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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CORE_ADDR pc;
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const struct block *bl;
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int inline_count;
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if (!get_frame_address_in_block_if_available (frame, &pc))
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return NULL;
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if (addr_in_block)
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*addr_in_block = pc;
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bl = block_for_pc (pc);
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if (bl == NULL)
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return NULL;
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inline_count = frame_inlined_callees (frame);
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while (inline_count > 0)
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{
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if (block_inlined_p (bl))
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inline_count--;
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bl = BLOCK_SUPERBLOCK (bl);
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gdb_assert (bl != NULL);
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}
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return bl;
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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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const struct block *bl;
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struct bound_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_ENTRY_PC (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.minsym)
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{
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CORE_ADDR fstart = BMSYMBOL_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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const struct block *bl = get_frame_block (frame, 0);
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if (bl == NULL)
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return NULL;
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while (BLOCK_FUNCTION (bl) == NULL && BLOCK_SUPERBLOCK (bl) != NULL)
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bl = BLOCK_SUPERBLOCK (bl);
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return BLOCK_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 obj_section *section)
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{
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const 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.
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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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/* See symtab.h. */
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struct symbol *
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find_pc_sect_containing_function (CORE_ADDR pc, struct obj_section *section)
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{
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const block *bl = block_for_pc_sect (pc, section);
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if (bl == nullptr)
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return nullptr;
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return block_containing_function (bl);
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}
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/* These variables are used to cache the most recent result of
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find_pc_partial_function.
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The addresses cache_pc_function_low and cache_pc_function_high
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record the range in which PC was found during the most recent
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successful lookup. When the function occupies a single contiguous
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address range, these values correspond to the low and high
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addresses of the function. (The high address is actually one byte
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beyond the last byte of the function.) For a function with more
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than one (non-contiguous) range, the range in which PC was found is
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used to set the cache bounds.
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When determining whether or not these cached values apply to a
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particular PC value, PC must be within the range specified by
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cache_pc_function_low and cache_pc_function_high. In addition to
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PC being in that range, cache_pc_section must also match PC's
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section. See find_pc_partial_function() for details on both the
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comparison as well as how PC's section is determined.
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The other values aren't used for determining whether the cache
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applies, but are used for setting the outputs from
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find_pc_partial_function. cache_pc_function_low and
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cache_pc_function_high are used to set outputs as well. */
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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 const char *cache_pc_function_name = 0;
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static struct obj_section *cache_pc_function_section = NULL;
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static const struct block *cache_pc_function_block = nullptr;
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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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cache_pc_function_block = nullptr;
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}
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/* See symtab.h. */
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bool
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find_pc_partial_function (CORE_ADDR pc, const char **name, CORE_ADDR *address,
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CORE_ADDR *endaddr, const struct block **block)
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{
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struct obj_section *section;
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struct symbol *f;
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struct bound_minimal_symbol msymbol;
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struct compunit_symtab *compunit_symtab = NULL;
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CORE_ADDR mapped_pc;
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/* To ensure that the symbol returned belongs to the correct section
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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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section = find_pc_section (pc);
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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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for (objfile *objfile : current_program_space->objfiles ())
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{
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if (objfile->sf)
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{
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compunit_symtab
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= objfile->sf->qf->find_pc_sect_compunit_symtab (objfile, msymbol,
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mapped_pc,
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section,
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0);
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}
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if (compunit_symtab != NULL)
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break;
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}
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if (compunit_symtab != NULL)
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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 stack.c:find_frame_funname.
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We use BLOCK_ENTRY_PC instead of BLOCK_START_PC for this
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comparison because the minimal symbol should refer to the
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function's entry pc which is not necessarily the lowest
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address of the function. This will happen when the function
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has more than one range and the entry pc is not within the
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lowest range of addresses. */
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f = find_pc_sect_function (mapped_pc, section);
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if (f != NULL
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&& (msymbol.minsym == NULL
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|| (BLOCK_ENTRY_PC (SYMBOL_BLOCK_VALUE (f))
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>= BMSYMBOL_VALUE_ADDRESS (msymbol))))
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{
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const struct block *b = SYMBOL_BLOCK_VALUE (f);
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cache_pc_function_name = f->linkage_name ();
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cache_pc_function_section = section;
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cache_pc_function_block = b;
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/* For blocks occupying contiguous addresses (i.e. no gaps),
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the low and high cache addresses are simply the start
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and end of the block.
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For blocks with non-contiguous ranges, we have to search
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for the range containing mapped_pc and then use the start
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and end of that range.
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This causes the returned *ADDRESS and *ENDADDR values to
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be limited to the range in which mapped_pc is found. See
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comment preceding declaration of find_pc_partial_function
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in symtab.h for more information. */
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if (BLOCK_CONTIGUOUS_P (b))
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{
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cache_pc_function_low = BLOCK_START (b);
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cache_pc_function_high = BLOCK_END (b);
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}
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else
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{
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int i;
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for (i = 0; i < BLOCK_NRANGES (b); i++)
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{
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if (BLOCK_RANGE_START (b, i) <= mapped_pc
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&& mapped_pc < BLOCK_RANGE_END (b, i))
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{
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cache_pc_function_low = BLOCK_RANGE_START (b, i);
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cache_pc_function_high = BLOCK_RANGE_END (b, i);
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break;
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}
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}
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/* Above loop should exit via the break. */
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gdb_assert (i < BLOCK_NRANGES (b));
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}
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goto return_cached_value;
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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
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section. If it's not, then give up. This ensures that anything
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beyond the end of the text seg doesn't appear to be part of the
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last function in the text segment. */
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if (!section)
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msymbol.minsym = NULL;
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/* Must be in the minimal symbol table. */
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if (msymbol.minsym == 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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if (block != nullptr)
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*block = nullptr;
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return false;
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}
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cache_pc_function_low = BMSYMBOL_VALUE_ADDRESS (msymbol);
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cache_pc_function_name = msymbol.minsym->linkage_name ();
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cache_pc_function_section = section;
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cache_pc_function_high = minimal_symbol_upper_bound (msymbol);
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cache_pc_function_block = nullptr;
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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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if (block != nullptr)
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*block = cache_pc_function_block;
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return true;
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}
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/* See symtab.h. */
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bool
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find_function_entry_range_from_pc (CORE_ADDR pc, const char **name,
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CORE_ADDR *address, CORE_ADDR *endaddr)
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{
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const struct block *block;
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bool status = find_pc_partial_function (pc, name, address, endaddr, &block);
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if (status && block != nullptr && !BLOCK_CONTIGUOUS_P (block))
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{
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CORE_ADDR entry_pc = BLOCK_ENTRY_PC (block);
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for (int i = 0; i < BLOCK_NRANGES (block); i++)
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{
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if (BLOCK_RANGE_START (block, i) <= entry_pc
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&& entry_pc < BLOCK_RANGE_END (block, i))
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{
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if (address != nullptr)
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*address = BLOCK_RANGE_START (block, i);
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if (endaddr != nullptr)
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*endaddr = BLOCK_RANGE_END (block, i);
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return status;
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}
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}
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/* It's an internal error if we exit the above loop without finding
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the range. */
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internal_error (__FILE__, __LINE__,
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_("Entry block not found in find_function_entry_range_from_pc"));
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}
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return status;
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}
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/* See symtab.h. */
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struct type *
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find_function_type (CORE_ADDR pc)
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{
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struct symbol *sym = find_pc_function (pc);
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if (sym != NULL && BLOCK_ENTRY_PC (SYMBOL_BLOCK_VALUE (sym)) == pc)
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return SYMBOL_TYPE (sym);
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return NULL;
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}
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/* See symtab.h. */
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struct type *
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find_gnu_ifunc_target_type (CORE_ADDR resolver_funaddr)
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{
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struct type *resolver_type = find_function_type (resolver_funaddr);
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if (resolver_type != NULL)
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{
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/* Get the return type of the resolver. */
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struct type *resolver_ret_type
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= check_typedef (TYPE_TARGET_TYPE (resolver_type));
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/* If we found a pointer to function, then the resolved type
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is the type of the pointed-to function. */
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if (TYPE_CODE (resolver_ret_type) == TYPE_CODE_PTR)
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{
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struct type *resolved_type
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= TYPE_TARGET_TYPE (resolver_ret_type);
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if (TYPE_CODE (check_typedef (resolved_type)) == TYPE_CODE_FUNC)
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return resolved_type;
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}
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}
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return NULL;
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}
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/* Return the innermost stack frame that is executing inside of BLOCK and is
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at least as old as the selected frame. Return NULL if there is no
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such frame. If BLOCK is NULL, just return NULL. */
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struct frame_info *
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block_innermost_frame (const struct block *block)
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{
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struct frame_info *frame;
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if (block == NULL)
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return NULL;
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frame = get_selected_frame_if_set ();
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if (frame == NULL)
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frame = get_current_frame ();
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while (frame != NULL)
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{
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const struct block *frame_block = get_frame_block (frame, NULL);
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if (frame_block != NULL && contained_in (frame_block, block))
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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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