mirror of
https://sourceware.org/git/binutils-gdb.git
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c9d95fa3d0
Improves readability. In the future, it will also allow making the name private, once the name setter functions become member functions. gdb/ChangeLog: 2019-11-22 Christian Biesinger <cbiesinger@google.com> * ada-lang.c (ada_lookup_simple_minsym): Update. (ada_collect_symbol_completion_matches): Update. * ada-tasks.c (read_atcb): Update. * amd64-windows-tdep.c (amd64_skip_main_prologue): Update. (amd64_windows_skip_trampoline_code): Update. * arm-tdep.c (skip_prologue_function): Update. (arm_skip_stack_protector): Update. * arm-wince-tdep.c (arm_pe_skip_trampoline_code): Update. (arm_wince_skip_main_prologue): Update. * ax-gdb.c (gen_expr): Update. * block.c (call_site_for_pc): Update. * blockframe.c (find_pc_partial_function): Update. * breakpoint.c (set_breakpoint_location_function): Update. * btrace.c (ftrace_print_function_name): Update. (ftrace_function_switched): Update. * c-valprint.c (print_unpacked_pointer): Update. * coffread.c (coff_symfile_read): Update. * compile/compile-c-symbols.c (convert_symbol_bmsym): Update. * compile/compile-cplus-symbols.c (convert_symbol_bmsym): Update. * dwarf-index-write.c (write_psymbols): Update. * dwarf2loc.c (call_site_to_target_addr): Update. (func_verify_no_selftailcall): Update. (tailcall_dump): Update. (call_site_find_chain_1): Update. (dwarf_expr_reg_to_entry_parameter): Update. * elfread.c (elf_gnu_ifunc_record_cache): Update. * eval.c (evaluate_funcall): Update. (evaluate_subexp_standard): Update. (evaluate_subexp_for_sizeof): Update. * expprint.c (print_subexp_standard): Update. (dump_subexp_body_standard): Update. * frame.c (get_prev_frame_always_1): Update. * frv-tdep.c (frv_skip_main_prologue): Update. * gnu-v2-abi.c (gnuv2_value_rtti_type): Update. * gnu-v3-abi.c (gnuv3_rtti_type): Update. (gnuv3_get_typename_from_type_info): Update. (gnuv3_skip_trampoline): Update. * hppa-tdep.c (hppa_lookup_stub_minimal_symbol): Update. * i386-tdep.c (i386_skip_main_prologue): Update. (i386_pe_skip_trampoline_code): Update. * ia64-tdep.c (ia64_convert_from_func_ptr_addr): Update. * infcall.c (get_function_name): Update. * linespec.c (minsym_found): Update. * linux-fork.c (info_checkpoints_command): Update. * m32c-tdep.c (m32c_m16c_address_to_pointer): Update. (m32c_m16c_pointer_to_address): Update. * maint.c (maintenance_translate_address): Update. * minsyms.c (add_minsym_to_hash_table): Update. (add_minsym_to_demangled_hash_table): Update. (lookup_minimal_symbol_mangled): Update. (lookup_minimal_symbol_demangled): Update. (lookup_minimal_symbol_linkage): Update. (lookup_minimal_symbol_text): Update. (lookup_minimal_symbol_by_pc_name): Update. (minimal_symbol_is_less_than): Update. (compact_minimal_symbols): Update. (build_minimal_symbol_hash_tables): Update. (find_solib_trampoline_target): Update. * mips-tdep.c (mips_stub_frame_sniffer): Update. (mips_skip_pic_trampoline_code): Update. * msp430-tdep.c (msp430_skip_trampoline_code): Update. * objc-lang.c (info_selectors_command): Update. (info_classes_command): Update. (find_methods): Update. (find_imps): Update. * p-valprint.c (pascal_val_print): Update. * ppc-linux-tdep.c (powerpc_linux_in_dynsym_resolve_code): Update. * ppc-sysv-tdep.c (convert_code_addr_to_desc_addr): Update. * printcmd.c (build_address_symbolic): Update. (info_symbol_command): Update. * psymtab.c (psymbol_name_matches): Update. (match_partial_symbol): Update. (lookup_partial_symbol): Update. (print_partial_symbols): Update. (sort_pst_symbols): Update. (maintenance_check_psymtabs): Update. * python/py-framefilter.c (py_print_frame): Update. * python/python.c (gdbpy_rbreak): Update. * record-btrace.c (btrace_get_bfun_name): Update. (btrace_call_history): Update. * rs6000-tdep.c (rs6000_skip_main_prologue): Update. (rs6000_skip_trampoline_code): Update. * sol-thread.c (info_cb): Update. * stabsread.c (scan_file_globals): Update. * stack.c (find_frame_funname): Update. (info_frame_command_core): Update. * symmisc.c (dump_msymbols): Update. * symtab.c (symbol_natural_name): Rename to.., (general_symbol_info::natural_name): ...this. (symbol_demangled_name): Rename to... (general_symbol_info::demangled_name): ...this. (symbol_search_name): Rename to... (general_symbol_info::search_name): ...this. (symbol_matches_search_name): Update. (find_pc_sect_line): Update. (skip_prologue_sal): Update. (search_symbols): Update. (print_msymbol_info): Update. (rbreak_command): Update. (completion_list_add_msymbol): Update. (completion_list_objc_symbol): Update. (get_msymbol_address): Update. * symtab.h (struct general_symbol_info): Add member functions natural_name (), linkage_name (), print_name (), demangled_name (), and search_name (). (SYMBOL_NATURAL_NAME): Update. (symbol_natural_name): Move to a member function on general_symbol_info. (SYMBOL_DEMANGLED_NAME): Update. (symbol_demangled_name): Move to a member function on general_symbol_info. (SYMBOL_SEARCH_NAME): Update. (symbol_search_name): Move to a member function on general_symbol_info. (MSYMBOL_NATURAL_NAME): Remove. (MSYMBOL_LINKAGE_NAME): Remove. (MSYMBOL_PRINT_NAME): Remove. (MSYMBOL_DEMANGLED_NAME): Remove. (MSYMBOL_SEARCH_NAME): Remove. * x86-tdep.c (x86_in_indirect_branch_thunk): Update. Change-Id: I65aa529843a9903e174ce799037e41f954a9fcee
1479 lines
47 KiB
C
1479 lines
47 KiB
C
/* Read ELF (Executable and Linking Format) object files for GDB.
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Copyright (C) 1991-2019 Free Software Foundation, Inc.
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Written by Fred Fish at Cygnus Support.
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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 "bfd.h"
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#include "elf-bfd.h"
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#include "elf/common.h"
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#include "elf/internal.h"
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#include "elf/mips.h"
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#include "symtab.h"
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#include "symfile.h"
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#include "objfiles.h"
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#include "stabsread.h"
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#include "complaints.h"
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#include "demangle.h"
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#include "psympriv.h"
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#include "filenames.h"
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#include "probe.h"
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#include "arch-utils.h"
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#include "gdbtypes.h"
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#include "value.h"
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#include "infcall.h"
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#include "gdbthread.h"
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#include "inferior.h"
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#include "regcache.h"
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#include "bcache.h"
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#include "gdb_bfd.h"
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#include "build-id.h"
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#include "location.h"
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#include "auxv.h"
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#include "mdebugread.h"
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#include "ctfread.h"
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#include "gdbsupport/gdb_string_view.h"
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/* Forward declarations. */
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extern const struct sym_fns elf_sym_fns_gdb_index;
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extern const struct sym_fns elf_sym_fns_debug_names;
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extern const struct sym_fns elf_sym_fns_lazy_psyms;
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/* The struct elfinfo is available only during ELF symbol table and
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psymtab reading. It is destroyed at the completion of psymtab-reading.
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It's local to elf_symfile_read. */
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struct elfinfo
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{
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asection *stabsect; /* Section pointer for .stab section */
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asection *mdebugsect; /* Section pointer for .mdebug section */
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asection *ctfsect; /* Section pointer for .ctf section */
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};
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/* Type for per-BFD data. */
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typedef std::vector<std::unique_ptr<probe>> elfread_data;
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/* Per-BFD data for probe info. */
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static const struct bfd_key<elfread_data> probe_key;
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/* Minimal symbols located at the GOT entries for .plt - that is the real
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pointer where the given entry will jump to. It gets updated by the real
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function address during lazy ld.so resolving in the inferior. These
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minimal symbols are indexed for <tab>-completion. */
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#define SYMBOL_GOT_PLT_SUFFIX "@got.plt"
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/* Locate the segments in ABFD. */
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static struct symfile_segment_data *
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elf_symfile_segments (bfd *abfd)
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{
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Elf_Internal_Phdr *phdrs, **segments;
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long phdrs_size;
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int num_phdrs, num_segments, num_sections, i;
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asection *sect;
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struct symfile_segment_data *data;
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phdrs_size = bfd_get_elf_phdr_upper_bound (abfd);
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if (phdrs_size == -1)
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return NULL;
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phdrs = (Elf_Internal_Phdr *) alloca (phdrs_size);
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num_phdrs = bfd_get_elf_phdrs (abfd, phdrs);
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if (num_phdrs == -1)
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return NULL;
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num_segments = 0;
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segments = XALLOCAVEC (Elf_Internal_Phdr *, num_phdrs);
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for (i = 0; i < num_phdrs; i++)
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if (phdrs[i].p_type == PT_LOAD)
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segments[num_segments++] = &phdrs[i];
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if (num_segments == 0)
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return NULL;
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data = XCNEW (struct symfile_segment_data);
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data->num_segments = num_segments;
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data->segment_bases = XCNEWVEC (CORE_ADDR, num_segments);
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data->segment_sizes = XCNEWVEC (CORE_ADDR, num_segments);
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for (i = 0; i < num_segments; i++)
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{
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data->segment_bases[i] = segments[i]->p_vaddr;
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data->segment_sizes[i] = segments[i]->p_memsz;
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}
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num_sections = bfd_count_sections (abfd);
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data->segment_info = XCNEWVEC (int, num_sections);
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for (i = 0, sect = abfd->sections; sect != NULL; i++, sect = sect->next)
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{
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int j;
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if ((bfd_section_flags (sect) & SEC_ALLOC) == 0)
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continue;
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Elf_Internal_Shdr *this_hdr = &elf_section_data (sect)->this_hdr;
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for (j = 0; j < num_segments; j++)
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if (ELF_SECTION_IN_SEGMENT (this_hdr, segments[j]))
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{
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data->segment_info[i] = j + 1;
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break;
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}
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/* We should have found a segment for every non-empty section.
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If we haven't, we will not relocate this section by any
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offsets we apply to the segments. As an exception, do not
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warn about SHT_NOBITS sections; in normal ELF execution
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environments, SHT_NOBITS means zero-initialized and belongs
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in a segment, but in no-OS environments some tools (e.g. ARM
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RealView) use SHT_NOBITS for uninitialized data. Since it is
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uninitialized, it doesn't need a program header. Such
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binaries are not relocatable. */
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if (bfd_section_size (sect) > 0 && j == num_segments
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&& (bfd_section_flags (sect) & SEC_LOAD) != 0)
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warning (_("Loadable section \"%s\" outside of ELF segments"),
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bfd_section_name (sect));
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}
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return data;
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}
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/* We are called once per section from elf_symfile_read. We
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need to examine each section we are passed, check to see
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if it is something we are interested in processing, and
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if so, stash away some access information for the section.
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For now we recognize the dwarf debug information sections and
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line number sections from matching their section names. The
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ELF definition is no real help here since it has no direct
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knowledge of DWARF (by design, so any debugging format can be
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used).
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We also recognize the ".stab" sections used by the Sun compilers
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released with Solaris 2.
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FIXME: The section names should not be hardwired strings (what
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should they be? I don't think most object file formats have enough
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section flags to specify what kind of debug section it is.
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-kingdon). */
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static void
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elf_locate_sections (bfd *ignore_abfd, asection *sectp, void *eip)
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{
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struct elfinfo *ei;
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ei = (struct elfinfo *) eip;
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if (strcmp (sectp->name, ".stab") == 0)
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{
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ei->stabsect = sectp;
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}
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else if (strcmp (sectp->name, ".mdebug") == 0)
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{
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ei->mdebugsect = sectp;
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}
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else if (strcmp (sectp->name, ".ctf") == 0)
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{
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ei->ctfsect = sectp;
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}
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}
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static struct minimal_symbol *
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record_minimal_symbol (minimal_symbol_reader &reader,
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gdb::string_view name, bool copy_name,
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CORE_ADDR address,
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enum minimal_symbol_type ms_type,
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asection *bfd_section, struct objfile *objfile)
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{
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struct gdbarch *gdbarch = get_objfile_arch (objfile);
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if (ms_type == mst_text || ms_type == mst_file_text
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|| ms_type == mst_text_gnu_ifunc)
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address = gdbarch_addr_bits_remove (gdbarch, address);
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struct minimal_symbol *result
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= reader.record_full (name, copy_name, address,
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ms_type,
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gdb_bfd_section_index (objfile->obfd,
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bfd_section));
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if ((objfile->flags & OBJF_MAINLINE) == 0
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&& (ms_type == mst_data || ms_type == mst_bss))
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result->maybe_copied = 1;
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return result;
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}
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/* Read the symbol table of an ELF file.
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Given an objfile, a symbol table, and a flag indicating whether the
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symbol table contains regular, dynamic, or synthetic symbols, add all
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the global function and data symbols to the minimal symbol table.
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In stabs-in-ELF, as implemented by Sun, there are some local symbols
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defined in the ELF symbol table, which can be used to locate
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the beginnings of sections from each ".o" file that was linked to
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form the executable objfile. We gather any such info and record it
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in data structures hung off the objfile's private data. */
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#define ST_REGULAR 0
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#define ST_DYNAMIC 1
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#define ST_SYNTHETIC 2
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static void
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elf_symtab_read (minimal_symbol_reader &reader,
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struct objfile *objfile, int type,
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long number_of_symbols, asymbol **symbol_table,
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bool copy_names)
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{
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struct gdbarch *gdbarch = get_objfile_arch (objfile);
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asymbol *sym;
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long i;
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CORE_ADDR symaddr;
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enum minimal_symbol_type ms_type;
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/* Name of the last file symbol. This is either a constant string or is
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saved on the objfile's filename cache. */
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const char *filesymname = "";
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int stripped = (bfd_get_symcount (objfile->obfd) == 0);
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int elf_make_msymbol_special_p
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= gdbarch_elf_make_msymbol_special_p (gdbarch);
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for (i = 0; i < number_of_symbols; i++)
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{
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sym = symbol_table[i];
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if (sym->name == NULL || *sym->name == '\0')
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{
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/* Skip names that don't exist (shouldn't happen), or names
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that are null strings (may happen). */
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continue;
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}
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/* Skip "special" symbols, e.g. ARM mapping symbols. These are
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symbols which do not correspond to objects in the symbol table,
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but have some other target-specific meaning. */
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if (bfd_is_target_special_symbol (objfile->obfd, sym))
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{
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if (gdbarch_record_special_symbol_p (gdbarch))
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gdbarch_record_special_symbol (gdbarch, objfile, sym);
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continue;
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}
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if (type == ST_DYNAMIC
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&& sym->section == bfd_und_section_ptr
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&& (sym->flags & BSF_FUNCTION))
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{
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struct minimal_symbol *msym;
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bfd *abfd = objfile->obfd;
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asection *sect;
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/* Symbol is a reference to a function defined in
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a shared library.
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If its value is non zero then it is usually the address
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of the corresponding entry in the procedure linkage table,
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plus the desired section offset.
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If its value is zero then the dynamic linker has to resolve
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the symbol. We are unable to find any meaningful address
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for this symbol in the executable file, so we skip it. */
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symaddr = sym->value;
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if (symaddr == 0)
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continue;
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/* sym->section is the undefined section. However, we want to
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record the section where the PLT stub resides with the
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minimal symbol. Search the section table for the one that
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covers the stub's address. */
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for (sect = abfd->sections; sect != NULL; sect = sect->next)
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{
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if ((bfd_section_flags (sect) & SEC_ALLOC) == 0)
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continue;
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if (symaddr >= bfd_section_vma (sect)
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&& symaddr < bfd_section_vma (sect)
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+ bfd_section_size (sect))
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break;
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}
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if (!sect)
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continue;
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/* On ia64-hpux, we have discovered that the system linker
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adds undefined symbols with nonzero addresses that cannot
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be right (their address points inside the code of another
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function in the .text section). This creates problems
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when trying to determine which symbol corresponds to
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a given address.
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We try to detect those buggy symbols by checking which
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section we think they correspond to. Normally, PLT symbols
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are stored inside their own section, and the typical name
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for that section is ".plt". So, if there is a ".plt"
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section, and yet the section name of our symbol does not
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start with ".plt", we ignore that symbol. */
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if (!startswith (sect->name, ".plt")
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&& bfd_get_section_by_name (abfd, ".plt") != NULL)
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continue;
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msym = record_minimal_symbol
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(reader, sym->name, copy_names,
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symaddr, mst_solib_trampoline, sect, objfile);
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if (msym != NULL)
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{
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msym->filename = filesymname;
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if (elf_make_msymbol_special_p)
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gdbarch_elf_make_msymbol_special (gdbarch, sym, msym);
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}
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continue;
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}
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/* If it is a nonstripped executable, do not enter dynamic
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symbols, as the dynamic symbol table is usually a subset
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of the main symbol table. */
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if (type == ST_DYNAMIC && !stripped)
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continue;
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if (sym->flags & BSF_FILE)
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{
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filesymname
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= ((const char *) objfile->per_bfd->filename_cache.insert
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(sym->name, strlen (sym->name) + 1));
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}
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else if (sym->flags & BSF_SECTION_SYM)
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continue;
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else if (sym->flags & (BSF_GLOBAL | BSF_LOCAL | BSF_WEAK
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| BSF_GNU_UNIQUE))
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{
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struct minimal_symbol *msym;
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/* Select global/local/weak symbols. Note that bfd puts abs
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symbols in their own section, so all symbols we are
|
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interested in will have a section. */
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/* Bfd symbols are section relative. */
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symaddr = sym->value + sym->section->vma;
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/* For non-absolute symbols, use the type of the section
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they are relative to, to intuit text/data. Bfd provides
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||
no way of figuring this out for absolute symbols. */
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if (sym->section == bfd_abs_section_ptr)
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||
{
|
||
/* This is a hack to get the minimal symbol type
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right for Irix 5, which has absolute addresses
|
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with special section indices for dynamic symbols.
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|
||
NOTE: uweigand-20071112: Synthetic symbols do not
|
||
have an ELF-private part, so do not touch those. */
|
||
unsigned int shndx = type == ST_SYNTHETIC ? 0 :
|
||
((elf_symbol_type *) sym)->internal_elf_sym.st_shndx;
|
||
|
||
switch (shndx)
|
||
{
|
||
case SHN_MIPS_TEXT:
|
||
ms_type = mst_text;
|
||
break;
|
||
case SHN_MIPS_DATA:
|
||
ms_type = mst_data;
|
||
break;
|
||
case SHN_MIPS_ACOMMON:
|
||
ms_type = mst_bss;
|
||
break;
|
||
default:
|
||
ms_type = mst_abs;
|
||
}
|
||
|
||
/* If it is an Irix dynamic symbol, skip section name
|
||
symbols, relocate all others by section offset. */
|
||
if (ms_type != mst_abs)
|
||
{
|
||
if (sym->name[0] == '.')
|
||
continue;
|
||
}
|
||
}
|
||
else if (sym->section->flags & SEC_CODE)
|
||
{
|
||
if (sym->flags & (BSF_GLOBAL | BSF_WEAK | BSF_GNU_UNIQUE))
|
||
{
|
||
if (sym->flags & BSF_GNU_INDIRECT_FUNCTION)
|
||
ms_type = mst_text_gnu_ifunc;
|
||
else
|
||
ms_type = mst_text;
|
||
}
|
||
/* The BSF_SYNTHETIC check is there to omit ppc64 function
|
||
descriptors mistaken for static functions starting with 'L'.
|
||
*/
|
||
else if ((sym->name[0] == '.' && sym->name[1] == 'L'
|
||
&& (sym->flags & BSF_SYNTHETIC) == 0)
|
||
|| ((sym->flags & BSF_LOCAL)
|
||
&& sym->name[0] == '$'
|
||
&& sym->name[1] == 'L'))
|
||
/* Looks like a compiler-generated label. Skip
|
||
it. The assembler should be skipping these (to
|
||
keep executables small), but apparently with
|
||
gcc on the (deleted) delta m88k SVR4, it loses.
|
||
So to have us check too should be harmless (but
|
||
I encourage people to fix this in the assembler
|
||
instead of adding checks here). */
|
||
continue;
|
||
else
|
||
{
|
||
ms_type = mst_file_text;
|
||
}
|
||
}
|
||
else if (sym->section->flags & SEC_ALLOC)
|
||
{
|
||
if (sym->flags & (BSF_GLOBAL | BSF_WEAK | BSF_GNU_UNIQUE))
|
||
{
|
||
if (sym->flags & BSF_GNU_INDIRECT_FUNCTION)
|
||
{
|
||
ms_type = mst_data_gnu_ifunc;
|
||
}
|
||
else if (sym->section->flags & SEC_LOAD)
|
||
{
|
||
ms_type = mst_data;
|
||
}
|
||
else
|
||
{
|
||
ms_type = mst_bss;
|
||
}
|
||
}
|
||
else if (sym->flags & BSF_LOCAL)
|
||
{
|
||
if (sym->section->flags & SEC_LOAD)
|
||
{
|
||
ms_type = mst_file_data;
|
||
}
|
||
else
|
||
{
|
||
ms_type = mst_file_bss;
|
||
}
|
||
}
|
||
else
|
||
{
|
||
ms_type = mst_unknown;
|
||
}
|
||
}
|
||
else
|
||
{
|
||
/* FIXME: Solaris2 shared libraries include lots of
|
||
odd "absolute" and "undefined" symbols, that play
|
||
hob with actions like finding what function the PC
|
||
is in. Ignore them if they aren't text, data, or bss. */
|
||
/* ms_type = mst_unknown; */
|
||
continue; /* Skip this symbol. */
|
||
}
|
||
msym = record_minimal_symbol
|
||
(reader, sym->name, copy_names, symaddr,
|
||
ms_type, sym->section, objfile);
|
||
|
||
if (msym)
|
||
{
|
||
/* NOTE: uweigand-20071112: A synthetic symbol does not have an
|
||
ELF-private part. */
|
||
if (type != ST_SYNTHETIC)
|
||
{
|
||
/* Pass symbol size field in via BFD. FIXME!!! */
|
||
elf_symbol_type *elf_sym = (elf_symbol_type *) sym;
|
||
SET_MSYMBOL_SIZE (msym, elf_sym->internal_elf_sym.st_size);
|
||
}
|
||
|
||
msym->filename = filesymname;
|
||
if (elf_make_msymbol_special_p)
|
||
gdbarch_elf_make_msymbol_special (gdbarch, sym, msym);
|
||
}
|
||
|
||
/* If we see a default versioned symbol, install it under
|
||
its version-less name. */
|
||
if (msym != NULL)
|
||
{
|
||
const char *atsign = strchr (sym->name, '@');
|
||
|
||
if (atsign != NULL && atsign[1] == '@' && atsign > sym->name)
|
||
{
|
||
int len = atsign - sym->name;
|
||
|
||
record_minimal_symbol (reader,
|
||
gdb::string_view (sym->name, len),
|
||
true, symaddr, ms_type, sym->section,
|
||
objfile);
|
||
}
|
||
}
|
||
|
||
/* For @plt symbols, also record a trampoline to the
|
||
destination symbol. The @plt symbol will be used in
|
||
disassembly, and the trampoline will be used when we are
|
||
trying to find the target. */
|
||
if (msym && ms_type == mst_text && type == ST_SYNTHETIC)
|
||
{
|
||
int len = strlen (sym->name);
|
||
|
||
if (len > 4 && strcmp (sym->name + len - 4, "@plt") == 0)
|
||
{
|
||
struct minimal_symbol *mtramp;
|
||
|
||
mtramp = record_minimal_symbol
|
||
(reader, gdb::string_view (sym->name, len - 4), true,
|
||
symaddr, mst_solib_trampoline, sym->section, objfile);
|
||
if (mtramp)
|
||
{
|
||
SET_MSYMBOL_SIZE (mtramp, MSYMBOL_SIZE (msym));
|
||
mtramp->created_by_gdb = 1;
|
||
mtramp->filename = filesymname;
|
||
if (elf_make_msymbol_special_p)
|
||
gdbarch_elf_make_msymbol_special (gdbarch,
|
||
sym, mtramp);
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Build minimal symbols named `function@got.plt' (see SYMBOL_GOT_PLT_SUFFIX)
|
||
for later look ups of which function to call when user requests
|
||
a STT_GNU_IFUNC function. As the STT_GNU_IFUNC type is found at the target
|
||
library defining `function' we cannot yet know while reading OBJFILE which
|
||
of the SYMBOL_GOT_PLT_SUFFIX entries will be needed and later
|
||
DYN_SYMBOL_TABLE is no longer easily available for OBJFILE. */
|
||
|
||
static void
|
||
elf_rel_plt_read (minimal_symbol_reader &reader,
|
||
struct objfile *objfile, asymbol **dyn_symbol_table)
|
||
{
|
||
bfd *obfd = objfile->obfd;
|
||
const struct elf_backend_data *bed = get_elf_backend_data (obfd);
|
||
asection *relplt, *got_plt;
|
||
bfd_size_type reloc_count, reloc;
|
||
struct gdbarch *gdbarch = get_objfile_arch (objfile);
|
||
struct type *ptr_type = builtin_type (gdbarch)->builtin_data_ptr;
|
||
size_t ptr_size = TYPE_LENGTH (ptr_type);
|
||
|
||
if (objfile->separate_debug_objfile_backlink)
|
||
return;
|
||
|
||
got_plt = bfd_get_section_by_name (obfd, ".got.plt");
|
||
if (got_plt == NULL)
|
||
{
|
||
/* For platforms where there is no separate .got.plt. */
|
||
got_plt = bfd_get_section_by_name (obfd, ".got");
|
||
if (got_plt == NULL)
|
||
return;
|
||
}
|
||
|
||
/* Depending on system, we may find jump slots in a relocation
|
||
section for either .got.plt or .plt. */
|
||
asection *plt = bfd_get_section_by_name (obfd, ".plt");
|
||
int plt_elf_idx = (plt != NULL) ? elf_section_data (plt)->this_idx : -1;
|
||
|
||
int got_plt_elf_idx = elf_section_data (got_plt)->this_idx;
|
||
|
||
/* This search algorithm is from _bfd_elf_canonicalize_dynamic_reloc. */
|
||
for (relplt = obfd->sections; relplt != NULL; relplt = relplt->next)
|
||
{
|
||
const auto &this_hdr = elf_section_data (relplt)->this_hdr;
|
||
|
||
if (this_hdr.sh_type == SHT_REL || this_hdr.sh_type == SHT_RELA)
|
||
{
|
||
if (this_hdr.sh_info == plt_elf_idx
|
||
|| this_hdr.sh_info == got_plt_elf_idx)
|
||
break;
|
||
}
|
||
}
|
||
if (relplt == NULL)
|
||
return;
|
||
|
||
if (! bed->s->slurp_reloc_table (obfd, relplt, dyn_symbol_table, TRUE))
|
||
return;
|
||
|
||
std::string string_buffer;
|
||
|
||
/* Does ADDRESS reside in SECTION of OBFD? */
|
||
auto within_section = [obfd] (asection *section, CORE_ADDR address)
|
||
{
|
||
if (section == NULL)
|
||
return false;
|
||
|
||
return (bfd_section_vma (section) <= address
|
||
&& (address < bfd_section_vma (section)
|
||
+ bfd_section_size (section)));
|
||
};
|
||
|
||
reloc_count = relplt->size / elf_section_data (relplt)->this_hdr.sh_entsize;
|
||
for (reloc = 0; reloc < reloc_count; reloc++)
|
||
{
|
||
const char *name;
|
||
struct minimal_symbol *msym;
|
||
CORE_ADDR address;
|
||
const char *got_suffix = SYMBOL_GOT_PLT_SUFFIX;
|
||
const size_t got_suffix_len = strlen (SYMBOL_GOT_PLT_SUFFIX);
|
||
|
||
name = bfd_asymbol_name (*relplt->relocation[reloc].sym_ptr_ptr);
|
||
address = relplt->relocation[reloc].address;
|
||
|
||
asection *msym_section;
|
||
|
||
/* Does the pointer reside in either the .got.plt or .plt
|
||
sections? */
|
||
if (within_section (got_plt, address))
|
||
msym_section = got_plt;
|
||
else if (within_section (plt, address))
|
||
msym_section = plt;
|
||
else
|
||
continue;
|
||
|
||
/* We cannot check if NAME is a reference to
|
||
mst_text_gnu_ifunc/mst_data_gnu_ifunc as in OBJFILE the
|
||
symbol is undefined and the objfile having NAME defined may
|
||
not yet have been loaded. */
|
||
|
||
string_buffer.assign (name);
|
||
string_buffer.append (got_suffix, got_suffix + got_suffix_len);
|
||
|
||
msym = record_minimal_symbol (reader, string_buffer,
|
||
true, address, mst_slot_got_plt,
|
||
msym_section, objfile);
|
||
if (msym)
|
||
SET_MSYMBOL_SIZE (msym, ptr_size);
|
||
}
|
||
}
|
||
|
||
/* The data pointer is htab_t for gnu_ifunc_record_cache_unchecked. */
|
||
|
||
static const struct objfile_key<htab, htab_deleter>
|
||
elf_objfile_gnu_ifunc_cache_data;
|
||
|
||
/* Map function names to CORE_ADDR in elf_objfile_gnu_ifunc_cache_data. */
|
||
|
||
struct elf_gnu_ifunc_cache
|
||
{
|
||
/* This is always a function entry address, not a function descriptor. */
|
||
CORE_ADDR addr;
|
||
|
||
char name[1];
|
||
};
|
||
|
||
/* htab_hash for elf_objfile_gnu_ifunc_cache_data. */
|
||
|
||
static hashval_t
|
||
elf_gnu_ifunc_cache_hash (const void *a_voidp)
|
||
{
|
||
const struct elf_gnu_ifunc_cache *a
|
||
= (const struct elf_gnu_ifunc_cache *) a_voidp;
|
||
|
||
return htab_hash_string (a->name);
|
||
}
|
||
|
||
/* htab_eq for elf_objfile_gnu_ifunc_cache_data. */
|
||
|
||
static int
|
||
elf_gnu_ifunc_cache_eq (const void *a_voidp, const void *b_voidp)
|
||
{
|
||
const struct elf_gnu_ifunc_cache *a
|
||
= (const struct elf_gnu_ifunc_cache *) a_voidp;
|
||
const struct elf_gnu_ifunc_cache *b
|
||
= (const struct elf_gnu_ifunc_cache *) b_voidp;
|
||
|
||
return strcmp (a->name, b->name) == 0;
|
||
}
|
||
|
||
/* Record the target function address of a STT_GNU_IFUNC function NAME is the
|
||
function entry address ADDR. Return 1 if NAME and ADDR are considered as
|
||
valid and therefore they were successfully recorded, return 0 otherwise.
|
||
|
||
Function does not expect a duplicate entry. Use
|
||
elf_gnu_ifunc_resolve_by_cache first to check if the entry for NAME already
|
||
exists. */
|
||
|
||
static int
|
||
elf_gnu_ifunc_record_cache (const char *name, CORE_ADDR addr)
|
||
{
|
||
struct bound_minimal_symbol msym;
|
||
struct objfile *objfile;
|
||
htab_t htab;
|
||
struct elf_gnu_ifunc_cache entry_local, *entry_p;
|
||
void **slot;
|
||
|
||
msym = lookup_minimal_symbol_by_pc (addr);
|
||
if (msym.minsym == NULL)
|
||
return 0;
|
||
if (BMSYMBOL_VALUE_ADDRESS (msym) != addr)
|
||
return 0;
|
||
objfile = msym.objfile;
|
||
|
||
/* If .plt jumps back to .plt the symbol is still deferred for later
|
||
resolution and it has no use for GDB. */
|
||
const char *target_name = msym.minsym->linkage_name ();
|
||
size_t len = strlen (target_name);
|
||
|
||
/* Note we check the symbol's name instead of checking whether the
|
||
symbol is in the .plt section because some systems have @plt
|
||
symbols in the .text section. */
|
||
if (len > 4 && strcmp (target_name + len - 4, "@plt") == 0)
|
||
return 0;
|
||
|
||
htab = elf_objfile_gnu_ifunc_cache_data.get (objfile);
|
||
if (htab == NULL)
|
||
{
|
||
htab = htab_create_alloc (1, elf_gnu_ifunc_cache_hash,
|
||
elf_gnu_ifunc_cache_eq,
|
||
NULL, xcalloc, xfree);
|
||
elf_objfile_gnu_ifunc_cache_data.set (objfile, htab);
|
||
}
|
||
|
||
entry_local.addr = addr;
|
||
obstack_grow (&objfile->objfile_obstack, &entry_local,
|
||
offsetof (struct elf_gnu_ifunc_cache, name));
|
||
obstack_grow_str0 (&objfile->objfile_obstack, name);
|
||
entry_p
|
||
= (struct elf_gnu_ifunc_cache *) obstack_finish (&objfile->objfile_obstack);
|
||
|
||
slot = htab_find_slot (htab, entry_p, INSERT);
|
||
if (*slot != NULL)
|
||
{
|
||
struct elf_gnu_ifunc_cache *entry_found_p
|
||
= (struct elf_gnu_ifunc_cache *) *slot;
|
||
struct gdbarch *gdbarch = get_objfile_arch (objfile);
|
||
|
||
if (entry_found_p->addr != addr)
|
||
{
|
||
/* This case indicates buggy inferior program, the resolved address
|
||
should never change. */
|
||
|
||
warning (_("gnu-indirect-function \"%s\" has changed its resolved "
|
||
"function_address from %s to %s"),
|
||
name, paddress (gdbarch, entry_found_p->addr),
|
||
paddress (gdbarch, addr));
|
||
}
|
||
|
||
/* New ENTRY_P is here leaked/duplicate in the OBJFILE obstack. */
|
||
}
|
||
*slot = entry_p;
|
||
|
||
return 1;
|
||
}
|
||
|
||
/* Try to find the target resolved function entry address of a STT_GNU_IFUNC
|
||
function NAME. If the address is found it is stored to *ADDR_P (if ADDR_P
|
||
is not NULL) and the function returns 1. It returns 0 otherwise.
|
||
|
||
Only the elf_objfile_gnu_ifunc_cache_data hash table is searched by this
|
||
function. */
|
||
|
||
static int
|
||
elf_gnu_ifunc_resolve_by_cache (const char *name, CORE_ADDR *addr_p)
|
||
{
|
||
for (objfile *objfile : current_program_space->objfiles ())
|
||
{
|
||
htab_t htab;
|
||
struct elf_gnu_ifunc_cache *entry_p;
|
||
void **slot;
|
||
|
||
htab = elf_objfile_gnu_ifunc_cache_data.get (objfile);
|
||
if (htab == NULL)
|
||
continue;
|
||
|
||
entry_p = ((struct elf_gnu_ifunc_cache *)
|
||
alloca (sizeof (*entry_p) + strlen (name)));
|
||
strcpy (entry_p->name, name);
|
||
|
||
slot = htab_find_slot (htab, entry_p, NO_INSERT);
|
||
if (slot == NULL)
|
||
continue;
|
||
entry_p = (struct elf_gnu_ifunc_cache *) *slot;
|
||
gdb_assert (entry_p != NULL);
|
||
|
||
if (addr_p)
|
||
*addr_p = entry_p->addr;
|
||
return 1;
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Try to find the target resolved function entry address of a STT_GNU_IFUNC
|
||
function NAME. If the address is found it is stored to *ADDR_P (if ADDR_P
|
||
is not NULL) and the function returns 1. It returns 0 otherwise.
|
||
|
||
Only the SYMBOL_GOT_PLT_SUFFIX locations are searched by this function.
|
||
elf_gnu_ifunc_resolve_by_cache must have been already called for NAME to
|
||
prevent cache entries duplicates. */
|
||
|
||
static int
|
||
elf_gnu_ifunc_resolve_by_got (const char *name, CORE_ADDR *addr_p)
|
||
{
|
||
char *name_got_plt;
|
||
const size_t got_suffix_len = strlen (SYMBOL_GOT_PLT_SUFFIX);
|
||
|
||
name_got_plt = (char *) alloca (strlen (name) + got_suffix_len + 1);
|
||
sprintf (name_got_plt, "%s" SYMBOL_GOT_PLT_SUFFIX, name);
|
||
|
||
for (objfile *objfile : current_program_space->objfiles ())
|
||
{
|
||
bfd *obfd = objfile->obfd;
|
||
struct gdbarch *gdbarch = get_objfile_arch (objfile);
|
||
struct type *ptr_type = builtin_type (gdbarch)->builtin_data_ptr;
|
||
size_t ptr_size = TYPE_LENGTH (ptr_type);
|
||
CORE_ADDR pointer_address, addr;
|
||
asection *plt;
|
||
gdb_byte *buf = (gdb_byte *) alloca (ptr_size);
|
||
struct bound_minimal_symbol msym;
|
||
|
||
msym = lookup_minimal_symbol (name_got_plt, NULL, objfile);
|
||
if (msym.minsym == NULL)
|
||
continue;
|
||
if (MSYMBOL_TYPE (msym.minsym) != mst_slot_got_plt)
|
||
continue;
|
||
pointer_address = BMSYMBOL_VALUE_ADDRESS (msym);
|
||
|
||
plt = bfd_get_section_by_name (obfd, ".plt");
|
||
if (plt == NULL)
|
||
continue;
|
||
|
||
if (MSYMBOL_SIZE (msym.minsym) != ptr_size)
|
||
continue;
|
||
if (target_read_memory (pointer_address, buf, ptr_size) != 0)
|
||
continue;
|
||
addr = extract_typed_address (buf, ptr_type);
|
||
addr = gdbarch_convert_from_func_ptr_addr (gdbarch, addr,
|
||
current_top_target ());
|
||
addr = gdbarch_addr_bits_remove (gdbarch, addr);
|
||
|
||
if (elf_gnu_ifunc_record_cache (name, addr))
|
||
{
|
||
if (addr_p != NULL)
|
||
*addr_p = addr;
|
||
return 1;
|
||
}
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Try to find the target resolved function entry address of a STT_GNU_IFUNC
|
||
function NAME. If the address is found it is stored to *ADDR_P (if ADDR_P
|
||
is not NULL) and the function returns true. It returns false otherwise.
|
||
|
||
Both the elf_objfile_gnu_ifunc_cache_data hash table and
|
||
SYMBOL_GOT_PLT_SUFFIX locations are searched by this function. */
|
||
|
||
static bool
|
||
elf_gnu_ifunc_resolve_name (const char *name, CORE_ADDR *addr_p)
|
||
{
|
||
if (elf_gnu_ifunc_resolve_by_cache (name, addr_p))
|
||
return true;
|
||
|
||
if (elf_gnu_ifunc_resolve_by_got (name, addr_p))
|
||
return true;
|
||
|
||
return false;
|
||
}
|
||
|
||
/* Call STT_GNU_IFUNC - a function returning addresss of a real function to
|
||
call. PC is theSTT_GNU_IFUNC resolving function entry. The value returned
|
||
is the entry point of the resolved STT_GNU_IFUNC target function to call.
|
||
*/
|
||
|
||
static CORE_ADDR
|
||
elf_gnu_ifunc_resolve_addr (struct gdbarch *gdbarch, CORE_ADDR pc)
|
||
{
|
||
const char *name_at_pc;
|
||
CORE_ADDR start_at_pc, address;
|
||
struct type *func_func_type = builtin_type (gdbarch)->builtin_func_func;
|
||
struct value *function, *address_val;
|
||
CORE_ADDR hwcap = 0;
|
||
struct value *hwcap_val;
|
||
|
||
/* Try first any non-intrusive methods without an inferior call. */
|
||
|
||
if (find_pc_partial_function (pc, &name_at_pc, &start_at_pc, NULL)
|
||
&& start_at_pc == pc)
|
||
{
|
||
if (elf_gnu_ifunc_resolve_name (name_at_pc, &address))
|
||
return address;
|
||
}
|
||
else
|
||
name_at_pc = NULL;
|
||
|
||
function = allocate_value (func_func_type);
|
||
VALUE_LVAL (function) = lval_memory;
|
||
set_value_address (function, pc);
|
||
|
||
/* STT_GNU_IFUNC resolver functions usually receive the HWCAP vector as
|
||
parameter. FUNCTION is the function entry address. ADDRESS may be a
|
||
function descriptor. */
|
||
|
||
target_auxv_search (current_top_target (), AT_HWCAP, &hwcap);
|
||
hwcap_val = value_from_longest (builtin_type (gdbarch)
|
||
->builtin_unsigned_long, hwcap);
|
||
address_val = call_function_by_hand (function, NULL, hwcap_val);
|
||
address = value_as_address (address_val);
|
||
address = gdbarch_convert_from_func_ptr_addr (gdbarch, address, current_top_target ());
|
||
address = gdbarch_addr_bits_remove (gdbarch, address);
|
||
|
||
if (name_at_pc)
|
||
elf_gnu_ifunc_record_cache (name_at_pc, address);
|
||
|
||
return address;
|
||
}
|
||
|
||
/* Handle inferior hit of bp_gnu_ifunc_resolver, see its definition. */
|
||
|
||
static void
|
||
elf_gnu_ifunc_resolver_stop (struct breakpoint *b)
|
||
{
|
||
struct breakpoint *b_return;
|
||
struct frame_info *prev_frame = get_prev_frame (get_current_frame ());
|
||
struct frame_id prev_frame_id = get_stack_frame_id (prev_frame);
|
||
CORE_ADDR prev_pc = get_frame_pc (prev_frame);
|
||
int thread_id = inferior_thread ()->global_num;
|
||
|
||
gdb_assert (b->type == bp_gnu_ifunc_resolver);
|
||
|
||
for (b_return = b->related_breakpoint; b_return != b;
|
||
b_return = b_return->related_breakpoint)
|
||
{
|
||
gdb_assert (b_return->type == bp_gnu_ifunc_resolver_return);
|
||
gdb_assert (b_return->loc != NULL && b_return->loc->next == NULL);
|
||
gdb_assert (frame_id_p (b_return->frame_id));
|
||
|
||
if (b_return->thread == thread_id
|
||
&& b_return->loc->requested_address == prev_pc
|
||
&& frame_id_eq (b_return->frame_id, prev_frame_id))
|
||
break;
|
||
}
|
||
|
||
if (b_return == b)
|
||
{
|
||
/* No need to call find_pc_line for symbols resolving as this is only
|
||
a helper breakpointer never shown to the user. */
|
||
|
||
symtab_and_line sal;
|
||
sal.pspace = current_inferior ()->pspace;
|
||
sal.pc = prev_pc;
|
||
sal.section = find_pc_overlay (sal.pc);
|
||
sal.explicit_pc = 1;
|
||
b_return
|
||
= set_momentary_breakpoint (get_frame_arch (prev_frame), sal,
|
||
prev_frame_id,
|
||
bp_gnu_ifunc_resolver_return).release ();
|
||
|
||
/* set_momentary_breakpoint invalidates PREV_FRAME. */
|
||
prev_frame = NULL;
|
||
|
||
/* Add new b_return to the ring list b->related_breakpoint. */
|
||
gdb_assert (b_return->related_breakpoint == b_return);
|
||
b_return->related_breakpoint = b->related_breakpoint;
|
||
b->related_breakpoint = b_return;
|
||
}
|
||
}
|
||
|
||
/* Handle inferior hit of bp_gnu_ifunc_resolver_return, see its definition. */
|
||
|
||
static void
|
||
elf_gnu_ifunc_resolver_return_stop (struct breakpoint *b)
|
||
{
|
||
thread_info *thread = inferior_thread ();
|
||
struct gdbarch *gdbarch = get_frame_arch (get_current_frame ());
|
||
struct type *func_func_type = builtin_type (gdbarch)->builtin_func_func;
|
||
struct type *value_type = TYPE_TARGET_TYPE (func_func_type);
|
||
struct regcache *regcache = get_thread_regcache (thread);
|
||
struct value *func_func;
|
||
struct value *value;
|
||
CORE_ADDR resolved_address, resolved_pc;
|
||
|
||
gdb_assert (b->type == bp_gnu_ifunc_resolver_return);
|
||
|
||
while (b->related_breakpoint != b)
|
||
{
|
||
struct breakpoint *b_next = b->related_breakpoint;
|
||
|
||
switch (b->type)
|
||
{
|
||
case bp_gnu_ifunc_resolver:
|
||
break;
|
||
case bp_gnu_ifunc_resolver_return:
|
||
delete_breakpoint (b);
|
||
break;
|
||
default:
|
||
internal_error (__FILE__, __LINE__,
|
||
_("handle_inferior_event: Invalid "
|
||
"gnu-indirect-function breakpoint type %d"),
|
||
(int) b->type);
|
||
}
|
||
b = b_next;
|
||
}
|
||
gdb_assert (b->type == bp_gnu_ifunc_resolver);
|
||
gdb_assert (b->loc->next == NULL);
|
||
|
||
func_func = allocate_value (func_func_type);
|
||
VALUE_LVAL (func_func) = lval_memory;
|
||
set_value_address (func_func, b->loc->related_address);
|
||
|
||
value = allocate_value (value_type);
|
||
gdbarch_return_value (gdbarch, func_func, value_type, regcache,
|
||
value_contents_raw (value), NULL);
|
||
resolved_address = value_as_address (value);
|
||
resolved_pc = gdbarch_convert_from_func_ptr_addr (gdbarch,
|
||
resolved_address,
|
||
current_top_target ());
|
||
resolved_pc = gdbarch_addr_bits_remove (gdbarch, resolved_pc);
|
||
|
||
gdb_assert (current_program_space == b->pspace || b->pspace == NULL);
|
||
elf_gnu_ifunc_record_cache (event_location_to_string (b->location.get ()),
|
||
resolved_pc);
|
||
|
||
b->type = bp_breakpoint;
|
||
update_breakpoint_locations (b, current_program_space,
|
||
find_function_start_sal (resolved_pc, NULL, true),
|
||
{});
|
||
}
|
||
|
||
/* A helper function for elf_symfile_read that reads the minimal
|
||
symbols. */
|
||
|
||
static void
|
||
elf_read_minimal_symbols (struct objfile *objfile, int symfile_flags,
|
||
const struct elfinfo *ei)
|
||
{
|
||
bfd *synth_abfd, *abfd = objfile->obfd;
|
||
long symcount = 0, dynsymcount = 0, synthcount, storage_needed;
|
||
asymbol **symbol_table = NULL, **dyn_symbol_table = NULL;
|
||
asymbol *synthsyms;
|
||
|
||
if (symtab_create_debug)
|
||
{
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"Reading minimal symbols of objfile %s ...\n",
|
||
objfile_name (objfile));
|
||
}
|
||
|
||
/* If we already have minsyms, then we can skip some work here.
|
||
However, if there were stabs or mdebug sections, we go ahead and
|
||
redo all the work anyway, because the psym readers for those
|
||
kinds of debuginfo need extra information found here. This can
|
||
go away once all types of symbols are in the per-BFD object. */
|
||
if (objfile->per_bfd->minsyms_read
|
||
&& ei->stabsect == NULL
|
||
&& ei->mdebugsect == NULL
|
||
&& ei->ctfsect == NULL)
|
||
{
|
||
if (symtab_create_debug)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"... minimal symbols previously read\n");
|
||
return;
|
||
}
|
||
|
||
minimal_symbol_reader reader (objfile);
|
||
|
||
/* Process the normal ELF symbol table first. */
|
||
|
||
storage_needed = bfd_get_symtab_upper_bound (objfile->obfd);
|
||
if (storage_needed < 0)
|
||
error (_("Can't read symbols from %s: %s"),
|
||
bfd_get_filename (objfile->obfd),
|
||
bfd_errmsg (bfd_get_error ()));
|
||
|
||
if (storage_needed > 0)
|
||
{
|
||
/* Memory gets permanently referenced from ABFD after
|
||
bfd_canonicalize_symtab so it must not get freed before ABFD gets. */
|
||
|
||
symbol_table = (asymbol **) bfd_alloc (abfd, storage_needed);
|
||
symcount = bfd_canonicalize_symtab (objfile->obfd, symbol_table);
|
||
|
||
if (symcount < 0)
|
||
error (_("Can't read symbols from %s: %s"),
|
||
bfd_get_filename (objfile->obfd),
|
||
bfd_errmsg (bfd_get_error ()));
|
||
|
||
elf_symtab_read (reader, objfile, ST_REGULAR, symcount, symbol_table,
|
||
false);
|
||
}
|
||
|
||
/* Add the dynamic symbols. */
|
||
|
||
storage_needed = bfd_get_dynamic_symtab_upper_bound (objfile->obfd);
|
||
|
||
if (storage_needed > 0)
|
||
{
|
||
/* Memory gets permanently referenced from ABFD after
|
||
bfd_get_synthetic_symtab so it must not get freed before ABFD gets.
|
||
It happens only in the case when elf_slurp_reloc_table sees
|
||
asection->relocation NULL. Determining which section is asection is
|
||
done by _bfd_elf_get_synthetic_symtab which is all a bfd
|
||
implementation detail, though. */
|
||
|
||
dyn_symbol_table = (asymbol **) bfd_alloc (abfd, storage_needed);
|
||
dynsymcount = bfd_canonicalize_dynamic_symtab (objfile->obfd,
|
||
dyn_symbol_table);
|
||
|
||
if (dynsymcount < 0)
|
||
error (_("Can't read symbols from %s: %s"),
|
||
bfd_get_filename (objfile->obfd),
|
||
bfd_errmsg (bfd_get_error ()));
|
||
|
||
elf_symtab_read (reader, objfile, ST_DYNAMIC, dynsymcount,
|
||
dyn_symbol_table, false);
|
||
|
||
elf_rel_plt_read (reader, objfile, dyn_symbol_table);
|
||
}
|
||
|
||
/* Contrary to binutils --strip-debug/--only-keep-debug the strip command from
|
||
elfutils (eu-strip) moves even the .symtab section into the .debug file.
|
||
|
||
bfd_get_synthetic_symtab on ppc64 for each function descriptor ELF symbol
|
||
'name' creates a new BSF_SYNTHETIC ELF symbol '.name' with its code
|
||
address. But with eu-strip files bfd_get_synthetic_symtab would fail to
|
||
read the code address from .opd while it reads the .symtab section from
|
||
a separate debug info file as the .opd section is SHT_NOBITS there.
|
||
|
||
With SYNTH_ABFD the .opd section will be read from the original
|
||
backlinked binary where it is valid. */
|
||
|
||
if (objfile->separate_debug_objfile_backlink)
|
||
synth_abfd = objfile->separate_debug_objfile_backlink->obfd;
|
||
else
|
||
synth_abfd = abfd;
|
||
|
||
/* Add synthetic symbols - for instance, names for any PLT entries. */
|
||
|
||
synthcount = bfd_get_synthetic_symtab (synth_abfd, symcount, symbol_table,
|
||
dynsymcount, dyn_symbol_table,
|
||
&synthsyms);
|
||
if (synthcount > 0)
|
||
{
|
||
long i;
|
||
|
||
std::unique_ptr<asymbol *[]>
|
||
synth_symbol_table (new asymbol *[synthcount]);
|
||
for (i = 0; i < synthcount; i++)
|
||
synth_symbol_table[i] = synthsyms + i;
|
||
elf_symtab_read (reader, objfile, ST_SYNTHETIC, synthcount,
|
||
synth_symbol_table.get (), true);
|
||
|
||
xfree (synthsyms);
|
||
synthsyms = NULL;
|
||
}
|
||
|
||
/* Install any minimal symbols that have been collected as the current
|
||
minimal symbols for this objfile. The debug readers below this point
|
||
should not generate new minimal symbols; if they do it's their
|
||
responsibility to install them. "mdebug" appears to be the only one
|
||
which will do this. */
|
||
|
||
reader.install ();
|
||
|
||
if (symtab_create_debug)
|
||
fprintf_unfiltered (gdb_stdlog, "Done reading minimal symbols.\n");
|
||
}
|
||
|
||
/* Scan and build partial symbols for a symbol file.
|
||
We have been initialized by a call to elf_symfile_init, which
|
||
currently does nothing.
|
||
|
||
This function only does the minimum work necessary for letting the
|
||
user "name" things symbolically; it does not read the entire symtab.
|
||
Instead, it reads the external and static symbols and puts them in partial
|
||
symbol tables. When more extensive information is requested of a
|
||
file, the corresponding partial symbol table is mutated into a full
|
||
fledged symbol table by going back and reading the symbols
|
||
for real.
|
||
|
||
We look for sections with specific names, to tell us what debug
|
||
format to look for: FIXME!!!
|
||
|
||
elfstab_build_psymtabs() handles STABS symbols;
|
||
mdebug_build_psymtabs() handles ECOFF debugging information.
|
||
|
||
Note that ELF files have a "minimal" symbol table, which looks a lot
|
||
like a COFF symbol table, but has only the minimal information necessary
|
||
for linking. We process this also, and use the information to
|
||
build gdb's minimal symbol table. This gives us some minimal debugging
|
||
capability even for files compiled without -g. */
|
||
|
||
static void
|
||
elf_symfile_read (struct objfile *objfile, symfile_add_flags symfile_flags)
|
||
{
|
||
bfd *abfd = objfile->obfd;
|
||
struct elfinfo ei;
|
||
bool has_dwarf2 = true;
|
||
|
||
memset ((char *) &ei, 0, sizeof (ei));
|
||
if (!(objfile->flags & OBJF_READNEVER))
|
||
bfd_map_over_sections (abfd, elf_locate_sections, (void *) & ei);
|
||
|
||
elf_read_minimal_symbols (objfile, symfile_flags, &ei);
|
||
|
||
/* ELF debugging information is inserted into the psymtab in the
|
||
order of least informative first - most informative last. Since
|
||
the psymtab table is searched `most recent insertion first' this
|
||
increases the probability that more detailed debug information
|
||
for a section is found.
|
||
|
||
For instance, an object file might contain both .mdebug (XCOFF)
|
||
and .debug_info (DWARF2) sections then .mdebug is inserted first
|
||
(searched last) and DWARF2 is inserted last (searched first). If
|
||
we don't do this then the XCOFF info is found first - for code in
|
||
an included file XCOFF info is useless. */
|
||
|
||
if (ei.mdebugsect)
|
||
{
|
||
const struct ecoff_debug_swap *swap;
|
||
|
||
/* .mdebug section, presumably holding ECOFF debugging
|
||
information. */
|
||
swap = get_elf_backend_data (abfd)->elf_backend_ecoff_debug_swap;
|
||
if (swap)
|
||
elfmdebug_build_psymtabs (objfile, swap, ei.mdebugsect);
|
||
}
|
||
if (ei.stabsect)
|
||
{
|
||
asection *str_sect;
|
||
|
||
/* Stab sections have an associated string table that looks like
|
||
a separate section. */
|
||
str_sect = bfd_get_section_by_name (abfd, ".stabstr");
|
||
|
||
/* FIXME should probably warn about a stab section without a stabstr. */
|
||
if (str_sect)
|
||
elfstab_build_psymtabs (objfile,
|
||
ei.stabsect,
|
||
str_sect->filepos,
|
||
bfd_section_size (str_sect));
|
||
}
|
||
|
||
if (dwarf2_has_info (objfile, NULL, true))
|
||
{
|
||
dw_index_kind index_kind;
|
||
|
||
/* elf_sym_fns_gdb_index cannot handle simultaneous non-DWARF
|
||
debug information present in OBJFILE. If there is such debug
|
||
info present never use an index. */
|
||
if (!objfile_has_partial_symbols (objfile)
|
||
&& dwarf2_initialize_objfile (objfile, &index_kind))
|
||
{
|
||
switch (index_kind)
|
||
{
|
||
case dw_index_kind::GDB_INDEX:
|
||
objfile_set_sym_fns (objfile, &elf_sym_fns_gdb_index);
|
||
break;
|
||
case dw_index_kind::DEBUG_NAMES:
|
||
objfile_set_sym_fns (objfile, &elf_sym_fns_debug_names);
|
||
break;
|
||
}
|
||
}
|
||
else
|
||
{
|
||
/* It is ok to do this even if the stabs reader made some
|
||
partial symbols, because OBJF_PSYMTABS_READ has not been
|
||
set, and so our lazy reader function will still be called
|
||
when needed. */
|
||
objfile_set_sym_fns (objfile, &elf_sym_fns_lazy_psyms);
|
||
}
|
||
}
|
||
/* If the file has its own symbol tables it has no separate debug
|
||
info. `.dynsym'/`.symtab' go to MSYMBOLS, `.debug_info' goes to
|
||
SYMTABS/PSYMTABS. `.gnu_debuglink' may no longer be present with
|
||
`.note.gnu.build-id'.
|
||
|
||
.gnu_debugdata is !objfile_has_partial_symbols because it contains only
|
||
.symtab, not .debug_* section. But if we already added .gnu_debugdata as
|
||
an objfile via find_separate_debug_file_in_section there was no separate
|
||
debug info available. Therefore do not attempt to search for another one,
|
||
objfile->separate_debug_objfile->separate_debug_objfile GDB guarantees to
|
||
be NULL and we would possibly violate it. */
|
||
|
||
else if (!objfile_has_partial_symbols (objfile)
|
||
&& objfile->separate_debug_objfile == NULL
|
||
&& objfile->separate_debug_objfile_backlink == NULL)
|
||
{
|
||
std::string debugfile = find_separate_debug_file_by_buildid (objfile);
|
||
|
||
if (debugfile.empty ())
|
||
debugfile = find_separate_debug_file_by_debuglink (objfile);
|
||
|
||
if (!debugfile.empty ())
|
||
{
|
||
gdb_bfd_ref_ptr debug_bfd (symfile_bfd_open (debugfile.c_str ()));
|
||
|
||
symbol_file_add_separate (debug_bfd.get (), debugfile.c_str (),
|
||
symfile_flags, objfile);
|
||
}
|
||
else
|
||
has_dwarf2 = false;
|
||
}
|
||
|
||
/* Read the CTF section only if there is no DWARF info. */
|
||
if (!has_dwarf2 && ei.ctfsect)
|
||
{
|
||
elfctf_build_psymtabs (objfile);
|
||
}
|
||
}
|
||
|
||
/* Callback to lazily read psymtabs. */
|
||
|
||
static void
|
||
read_psyms (struct objfile *objfile)
|
||
{
|
||
if (dwarf2_has_info (objfile, NULL))
|
||
dwarf2_build_psymtabs (objfile);
|
||
}
|
||
|
||
/* Initialize anything that needs initializing when a completely new symbol
|
||
file is specified (not just adding some symbols from another file, e.g. a
|
||
shared library). */
|
||
|
||
static void
|
||
elf_new_init (struct objfile *ignore)
|
||
{
|
||
}
|
||
|
||
/* Perform any local cleanups required when we are done with a particular
|
||
objfile. I.E, we are in the process of discarding all symbol information
|
||
for an objfile, freeing up all memory held for it, and unlinking the
|
||
objfile struct from the global list of known objfiles. */
|
||
|
||
static void
|
||
elf_symfile_finish (struct objfile *objfile)
|
||
{
|
||
}
|
||
|
||
/* ELF specific initialization routine for reading symbols. */
|
||
|
||
static void
|
||
elf_symfile_init (struct objfile *objfile)
|
||
{
|
||
/* ELF objects may be reordered, so set OBJF_REORDERED. If we
|
||
find this causes a significant slowdown in gdb then we could
|
||
set it in the debug symbol readers only when necessary. */
|
||
objfile->flags |= OBJF_REORDERED;
|
||
}
|
||
|
||
/* Implementation of `sym_get_probes', as documented in symfile.h. */
|
||
|
||
static const elfread_data &
|
||
elf_get_probes (struct objfile *objfile)
|
||
{
|
||
elfread_data *probes_per_bfd = probe_key.get (objfile->obfd);
|
||
|
||
if (probes_per_bfd == NULL)
|
||
{
|
||
probes_per_bfd = probe_key.emplace (objfile->obfd);
|
||
|
||
/* Here we try to gather information about all types of probes from the
|
||
objfile. */
|
||
for (const static_probe_ops *ops : all_static_probe_ops)
|
||
ops->get_probes (probes_per_bfd, objfile);
|
||
}
|
||
|
||
return *probes_per_bfd;
|
||
}
|
||
|
||
|
||
|
||
/* Implementation `sym_probe_fns', as documented in symfile.h. */
|
||
|
||
static const struct sym_probe_fns elf_probe_fns =
|
||
{
|
||
elf_get_probes, /* sym_get_probes */
|
||
};
|
||
|
||
/* Register that we are able to handle ELF object file formats. */
|
||
|
||
static const struct sym_fns elf_sym_fns =
|
||
{
|
||
elf_new_init, /* init anything gbl to entire symtab */
|
||
elf_symfile_init, /* read initial info, setup for sym_read() */
|
||
elf_symfile_read, /* read a symbol file into symtab */
|
||
NULL, /* sym_read_psymbols */
|
||
elf_symfile_finish, /* finished with file, cleanup */
|
||
default_symfile_offsets, /* Translate ext. to int. relocation */
|
||
elf_symfile_segments, /* Get segment information from a file. */
|
||
NULL,
|
||
default_symfile_relocate, /* Relocate a debug section. */
|
||
&elf_probe_fns, /* sym_probe_fns */
|
||
&psym_functions
|
||
};
|
||
|
||
/* The same as elf_sym_fns, but not registered and lazily reads
|
||
psymbols. */
|
||
|
||
const struct sym_fns elf_sym_fns_lazy_psyms =
|
||
{
|
||
elf_new_init, /* init anything gbl to entire symtab */
|
||
elf_symfile_init, /* read initial info, setup for sym_read() */
|
||
elf_symfile_read, /* read a symbol file into symtab */
|
||
read_psyms, /* sym_read_psymbols */
|
||
elf_symfile_finish, /* finished with file, cleanup */
|
||
default_symfile_offsets, /* Translate ext. to int. relocation */
|
||
elf_symfile_segments, /* Get segment information from a file. */
|
||
NULL,
|
||
default_symfile_relocate, /* Relocate a debug section. */
|
||
&elf_probe_fns, /* sym_probe_fns */
|
||
&psym_functions
|
||
};
|
||
|
||
/* The same as elf_sym_fns, but not registered and uses the
|
||
DWARF-specific GNU index rather than psymtab. */
|
||
const struct sym_fns elf_sym_fns_gdb_index =
|
||
{
|
||
elf_new_init, /* init anything gbl to entire symab */
|
||
elf_symfile_init, /* read initial info, setup for sym_red() */
|
||
elf_symfile_read, /* read a symbol file into symtab */
|
||
NULL, /* sym_read_psymbols */
|
||
elf_symfile_finish, /* finished with file, cleanup */
|
||
default_symfile_offsets, /* Translate ext. to int. relocation */
|
||
elf_symfile_segments, /* Get segment information from a file. */
|
||
NULL,
|
||
default_symfile_relocate, /* Relocate a debug section. */
|
||
&elf_probe_fns, /* sym_probe_fns */
|
||
&dwarf2_gdb_index_functions
|
||
};
|
||
|
||
/* The same as elf_sym_fns, but not registered and uses the
|
||
DWARF-specific .debug_names index rather than psymtab. */
|
||
const struct sym_fns elf_sym_fns_debug_names =
|
||
{
|
||
elf_new_init, /* init anything gbl to entire symab */
|
||
elf_symfile_init, /* read initial info, setup for sym_red() */
|
||
elf_symfile_read, /* read a symbol file into symtab */
|
||
NULL, /* sym_read_psymbols */
|
||
elf_symfile_finish, /* finished with file, cleanup */
|
||
default_symfile_offsets, /* Translate ext. to int. relocation */
|
||
elf_symfile_segments, /* Get segment information from a file. */
|
||
NULL,
|
||
default_symfile_relocate, /* Relocate a debug section. */
|
||
&elf_probe_fns, /* sym_probe_fns */
|
||
&dwarf2_debug_names_functions
|
||
};
|
||
|
||
/* STT_GNU_IFUNC resolver vector to be installed to gnu_ifunc_fns_p. */
|
||
|
||
static const struct gnu_ifunc_fns elf_gnu_ifunc_fns =
|
||
{
|
||
elf_gnu_ifunc_resolve_addr,
|
||
elf_gnu_ifunc_resolve_name,
|
||
elf_gnu_ifunc_resolver_stop,
|
||
elf_gnu_ifunc_resolver_return_stop
|
||
};
|
||
|
||
void
|
||
_initialize_elfread (void)
|
||
{
|
||
add_symtab_fns (bfd_target_elf_flavour, &elf_sym_fns);
|
||
|
||
gnu_ifunc_fns_p = &elf_gnu_ifunc_fns;
|
||
}
|