| /* Read a symbol table in MIPS' format (Third-Eye). |
| |
| Copyright (C) 1986-2021 Free Software Foundation, Inc. |
| |
| Contributed by Alessandro Forin (af@cs.cmu.edu) at CMU. Major work |
| by Per Bothner, John Gilmore and Ian Lance Taylor at Cygnus Support. |
| |
| This file is part of GDB. |
| |
| This program is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 3 of the License, or |
| (at your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| |
| /* Read symbols from an ECOFF file. Most of the work is done in |
| mdebugread.c. */ |
| |
| #include "defs.h" |
| #include "bfd.h" |
| #include "symtab.h" |
| #include "objfiles.h" |
| #include "stabsread.h" |
| #include "mdebugread.h" |
| |
| #include "coff/sym.h" |
| #include "coff/internal.h" |
| #include "coff/ecoff.h" |
| #include "libcoff.h" /* Private BFD COFF information. */ |
| #include "libecoff.h" /* Private BFD ECOFF information. */ |
| #include "elf/common.h" |
| #include "elf/internal.h" |
| #include "elf/mips.h" |
| |
| #include "psymtab.h" |
| |
| static void |
| read_alphacoff_dynamic_symtab (minimal_symbol_reader &, |
| struct objfile *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 |
| mipscoff_new_init (struct objfile *ignore) |
| { |
| stabsread_new_init (); |
| } |
| |
| /* Initialize to read a symbol file (nothing to do). */ |
| |
| static void |
| mipscoff_symfile_init (struct objfile *objfile) |
| { |
| } |
| |
| /* Read a symbol file from a file. */ |
| |
| static void |
| mipscoff_symfile_read (struct objfile *objfile, symfile_add_flags symfile_flags) |
| { |
| bfd *abfd = objfile->obfd; |
| |
| minimal_symbol_reader reader (objfile); |
| |
| /* Now that the executable file is positioned at symbol table, |
| process it and define symbols accordingly. */ |
| |
| if (!((*ecoff_backend (abfd)->debug_swap.read_debug_info) |
| (abfd, NULL, &ecoff_data (abfd)->debug_info))) |
| error (_("Error reading symbol table: %s"), bfd_errmsg (bfd_get_error ())); |
| |
| mdebug_build_psymtabs (reader, objfile, &ecoff_backend (abfd)->debug_swap, |
| &ecoff_data (abfd)->debug_info); |
| |
| /* Add alpha coff dynamic symbols. */ |
| |
| read_alphacoff_dynamic_symtab (reader, objfile); |
| |
| /* Install any minimal symbols that have been collected as the current |
| minimal symbols for this objfile. */ |
| |
| reader.install (); |
| } |
| |
| /* Perform any local cleanups required when we are done with a |
| particular objfile. */ |
| |
| static void |
| mipscoff_symfile_finish (struct objfile *objfile) |
| { |
| } |
| |
| /* Alpha OSF/1 encapsulates the dynamic symbols in ELF format in a |
| standard COFF section. The ELF format for the symbols differs from |
| the format defined in elf/external.h. It seems that a normal ELF |
| 32-bit format is used, and the representation only changes because |
| longs are 64-bit on the alpha. In addition, the handling of |
| text/data section indices for symbols is different from the ELF |
| ABI. As the BFD linker currently does not support dynamic linking |
| on the alpha, there seems to be no reason to pollute BFD with |
| another mixture of object file formats for now. */ |
| |
| /* Format of an alpha external ELF symbol. */ |
| |
| typedef struct |
| { |
| unsigned char st_name[4]; /* Symbol name, index in string table. */ |
| unsigned char st_pad[4]; /* Pad to long word boundary. */ |
| unsigned char st_value[8]; /* Value of the symbol. */ |
| unsigned char st_size[4]; /* Associated symbol size. */ |
| unsigned char st_info[1]; /* Type and binding attributes. */ |
| unsigned char st_other[1]; /* No defined meaning, 0. */ |
| unsigned char st_shndx[2]; /* Associated section index. */ |
| } Elfalpha_External_Sym; |
| |
| /* Format of an alpha external ELF dynamic info structure. */ |
| |
| typedef struct |
| { |
| unsigned char d_tag[4]; /* Tag. */ |
| unsigned char d_pad[4]; /* Pad to long word boundary. */ |
| union |
| { |
| unsigned char d_ptr[8]; /* Pointer value. */ |
| unsigned char d_val[4]; /* Integer value. */ |
| } |
| d_un; |
| } Elfalpha_External_Dyn; |
| |
| /* Struct to obtain the section pointers for alpha dynamic symbol info. */ |
| |
| struct alphacoff_dynsecinfo |
| { |
| asection *sym_sect; /* Section pointer for .dynsym section. */ |
| asection *str_sect; /* Section pointer for .dynstr section. */ |
| asection *dyninfo_sect; /* Section pointer for .dynamic section. */ |
| asection *got_sect; /* Section pointer for .got section. */ |
| }; |
| |
| /* We are called once per section from read_alphacoff_dynamic_symtab. |
| We need to examine each section we are passed, check to see if it |
| is something we are interested in processing, and if so, stash away |
| some access information for the section. */ |
| |
| static void |
| alphacoff_locate_sections (bfd *ignore_abfd, asection *sectp, void *sip) |
| { |
| struct alphacoff_dynsecinfo *si; |
| |
| si = (struct alphacoff_dynsecinfo *) sip; |
| |
| if (strcmp (sectp->name, ".dynsym") == 0) |
| si->sym_sect = sectp; |
| else if (strcmp (sectp->name, ".dynstr") == 0) |
| si->str_sect = sectp; |
| else if (strcmp (sectp->name, ".dynamic") == 0) |
| si->dyninfo_sect = sectp; |
| else if (strcmp (sectp->name, ".got") == 0) |
| si->got_sect = sectp; |
| } |
| |
| /* Scan an alpha dynamic symbol table for symbols of interest and add |
| them to the minimal symbol table. */ |
| |
| static void |
| read_alphacoff_dynamic_symtab (minimal_symbol_reader &reader, |
| struct objfile *objfile) |
| { |
| bfd *abfd = objfile->obfd; |
| struct alphacoff_dynsecinfo si; |
| int sym_count; |
| int i; |
| int stripped; |
| Elfalpha_External_Sym *x_symp; |
| gdb_byte *dyninfo_p; |
| gdb_byte *dyninfo_end; |
| int got_entry_size = 8; |
| int dt_mips_local_gotno = -1; |
| int dt_mips_gotsym = -1; |
| |
| /* We currently only know how to handle alpha dynamic symbols. */ |
| if (bfd_get_arch (abfd) != bfd_arch_alpha) |
| return; |
| |
| /* Locate the dynamic symbols sections and read them in. */ |
| memset ((char *) &si, 0, sizeof (si)); |
| bfd_map_over_sections (abfd, alphacoff_locate_sections, (void *) & si); |
| if (si.sym_sect == NULL || si.str_sect == NULL |
| || si.dyninfo_sect == NULL || si.got_sect == NULL) |
| return; |
| |
| gdb::byte_vector sym_sec (bfd_section_size (si.sym_sect)); |
| gdb::byte_vector str_sec (bfd_section_size (si.str_sect)); |
| gdb::byte_vector dyninfo_sec (bfd_section_size (si.dyninfo_sect)); |
| gdb::byte_vector got_sec (bfd_section_size (si.got_sect)); |
| |
| if (!bfd_get_section_contents (abfd, si.sym_sect, sym_sec.data (), |
| (file_ptr) 0, sym_sec.size ())) |
| return; |
| if (!bfd_get_section_contents (abfd, si.str_sect, str_sec.data (), |
| (file_ptr) 0, str_sec.size ())) |
| return; |
| if (!bfd_get_section_contents (abfd, si.dyninfo_sect, dyninfo_sec.data (), |
| (file_ptr) 0, dyninfo_sec.size ())) |
| return; |
| if (!bfd_get_section_contents (abfd, si.got_sect, got_sec.data (), |
| (file_ptr) 0, got_sec.size ())) |
| return; |
| |
| /* Find the number of local GOT entries and the index for the |
| first dynamic symbol in the GOT. */ |
| for ((dyninfo_p = dyninfo_sec.data (), |
| dyninfo_end = dyninfo_p + dyninfo_sec.size ()); |
| dyninfo_p < dyninfo_end; |
| dyninfo_p += sizeof (Elfalpha_External_Dyn)) |
| { |
| Elfalpha_External_Dyn *x_dynp = (Elfalpha_External_Dyn *) dyninfo_p; |
| long dyn_tag; |
| |
| dyn_tag = bfd_h_get_32 (abfd, (bfd_byte *) x_dynp->d_tag); |
| if (dyn_tag == DT_NULL) |
| break; |
| else if (dyn_tag == DT_MIPS_LOCAL_GOTNO) |
| { |
| if (dt_mips_local_gotno < 0) |
| dt_mips_local_gotno |
| = bfd_h_get_32 (abfd, (bfd_byte *) x_dynp->d_un.d_val); |
| } |
| else if (dyn_tag == DT_MIPS_GOTSYM) |
| { |
| if (dt_mips_gotsym < 0) |
| dt_mips_gotsym |
| = bfd_h_get_32 (abfd, (bfd_byte *) x_dynp->d_un.d_val); |
| } |
| } |
| if (dt_mips_local_gotno < 0 || dt_mips_gotsym < 0) |
| return; |
| |
| /* Scan all dynamic symbols and enter them into the minimal symbol |
| table if appropriate. */ |
| sym_count = sym_sec.size () / sizeof (Elfalpha_External_Sym); |
| stripped = (bfd_get_symcount (abfd) == 0); |
| |
| /* Skip first symbol, which is a null dummy. */ |
| for (i = 1, x_symp = (Elfalpha_External_Sym *) sym_sec.data () + 1; |
| i < sym_count; |
| i++, x_symp++) |
| { |
| unsigned long strx; |
| char *name; |
| bfd_vma sym_value; |
| unsigned char sym_info; |
| unsigned int sym_shndx; |
| int isglobal; |
| enum minimal_symbol_type ms_type; |
| |
| strx = bfd_h_get_32 (abfd, (bfd_byte *) x_symp->st_name); |
| if (strx >= str_sec.size ()) |
| continue; |
| name = (char *) (str_sec.data () + strx); |
| if (*name == '\0' || *name == '.') |
| continue; |
| |
| sym_value = bfd_h_get_64 (abfd, (bfd_byte *) x_symp->st_value); |
| sym_info = bfd_h_get_8 (abfd, (bfd_byte *) x_symp->st_info); |
| sym_shndx = bfd_h_get_16 (abfd, (bfd_byte *) x_symp->st_shndx); |
| if (sym_shndx >= (SHN_LORESERVE & 0xffff)) |
| sym_shndx += SHN_LORESERVE - (SHN_LORESERVE & 0xffff); |
| isglobal = (ELF_ST_BIND (sym_info) == STB_GLOBAL); |
| |
| if (sym_shndx == SHN_UNDEF) |
| { |
| /* Handle undefined functions which are defined in a shared |
| library. */ |
| if (ELF_ST_TYPE (sym_info) != STT_FUNC |
| || ELF_ST_BIND (sym_info) != STB_GLOBAL) |
| continue; |
| |
| ms_type = mst_solib_trampoline; |
| |
| /* If sym_value is nonzero, it points to the shared library |
| trampoline entry, which is what we are looking for. |
| |
| If sym_value is zero, then we have to get the GOT entry |
| for the symbol. |
| |
| If the GOT entry is nonzero, it represents the quickstart |
| address of the function and we use that as the symbol |
| value. |
| |
| If the GOT entry is zero, the function address has to be |
| resolved by the runtime loader before the executable is |
| started. We are unable to find any meaningful address |
| for these functions in the executable file, so we skip |
| them. */ |
| if (sym_value == 0) |
| { |
| int got_entry_offset = |
| (i - dt_mips_gotsym + dt_mips_local_gotno) * got_entry_size; |
| |
| if (got_entry_offset < 0 |
| || got_entry_offset >= got_sec.size ()) |
| continue; |
| sym_value = |
| bfd_h_get_64 (abfd, |
| (bfd_byte *) (got_sec.data () |
| + got_entry_offset)); |
| if (sym_value == 0) |
| continue; |
| } |
| } |
| else |
| { |
| /* Symbols defined in the executable itself. We only care |
| about them if this is a stripped executable, otherwise |
| they have been retrieved from the normal symbol table |
| already. */ |
| if (!stripped) |
| continue; |
| |
| if (sym_shndx == SHN_MIPS_TEXT) |
| { |
| if (isglobal) |
| ms_type = mst_text; |
| else |
| ms_type = mst_file_text; |
| } |
| else if (sym_shndx == SHN_MIPS_DATA) |
| { |
| if (isglobal) |
| ms_type = mst_data; |
| else |
| ms_type = mst_file_data; |
| } |
| else if (sym_shndx == SHN_MIPS_ACOMMON) |
| { |
| if (isglobal) |
| ms_type = mst_bss; |
| else |
| ms_type = mst_file_bss; |
| } |
| else if (sym_shndx == SHN_ABS) |
| { |
| ms_type = mst_abs; |
| } |
| else |
| { |
| continue; |
| } |
| } |
| |
| reader.record (name, sym_value, ms_type); |
| } |
| } |
| |
| /* Initialization. */ |
| |
| static const struct sym_fns ecoff_sym_fns = |
| { |
| mipscoff_new_init, /* init anything gbl to entire symtab */ |
| mipscoff_symfile_init, /* read initial info, setup for sym_read() */ |
| mipscoff_symfile_read, /* read a symbol file into symtab */ |
| mipscoff_symfile_finish, /* finished with file, cleanup */ |
| default_symfile_offsets, /* dummy FIXME til implem sym reloc */ |
| default_symfile_segments, /* Get segment information from a file. */ |
| NULL, |
| default_symfile_relocate, /* Relocate a debug section. */ |
| NULL, /* sym_probe_fns */ |
| }; |
| |
| void _initialize_mipsread (); |
| void |
| _initialize_mipsread () |
| { |
| add_symtab_fns (bfd_target_ecoff_flavour, &ecoff_sym_fns); |
| } |