/* Read ELF (Executable and Linking Format) object files for GDB.
- Copyright (C) 1991 Free Software Foundation, Inc.
+ Copyright 1991, 1992 Free Software Foundation, Inc.
Written by Fred Fish at Cygnus Support.
This file is part of GDB.
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
-/************************************************************************
- * *
- * NOTICE *
- * *
- * This file is still under construction. When it is complete, this *
- * notice will be removed. Until then, direct any questions or changes *
- * to Fred Fish at Cygnus Support (fnf@cygint) *
- * *
- * FIXME Still needs support for shared libraries. *
- * FIXME Still needs support for core files. *
- * FIXME The ".debug" and ".line" section names are hardwired. *
- * FIXME Still needs support ELF symbol tables (as distinct *
- * from DWARF support). Can use them to build the misc *
- * function vector at least. This is fairly trivial once *
- * bfd is extended to handle ELF symbol tables. *
- * *
- ************************************************************************/
-
-#include <stdio.h>
-
#include "defs.h"
-#include "param.h"
-#include "elf-common.h"
-#include "elf-external.h"
-#include "elf-internal.h"
#include "bfd.h"
-#include "symfile.h"
+#include "libbfd.h" /* For bfd_elf_find_section */
+#include "libelf.h"
#include "symtab.h"
-#include "ansidecl.h"
-
-extern int EXFUN(strcmp, (CONST char *a, CONST char *b));
-#define STREQ(a,b) (strcmp((a),(b))==0)
+#include "symfile.h"
+#include "objfiles.h"
+#include "buildsym.h"
+#include "stabsread.h"
+#include "gdb-stabs.h"
+#include "complaints.h"
+#include <string.h>
+#include "demangle.h"
+
+/* The struct elfinfo is available only during ELF symbol table and
+ psymtab reading. It is destroyed at the complation of psymtab-reading.
+ It's local to elf_symfile_read. */
struct elfinfo {
- unsigned int dboffset; /* Offset to dwarf debug section */
+ file_ptr dboffset; /* Offset to dwarf debug section */
unsigned int dbsize; /* Size of dwarf debug section */
- unsigned int lnoffset; /* Offset to dwarf line number section */
+ file_ptr lnoffset; /* Offset to dwarf line number section */
unsigned int lnsize; /* Size of dwarf line number section */
+ asection *stabsect; /* Section pointer for .stab section */
+ asection *stabindexsect; /* Section pointer for .stab.index section */
};
-#if 0
-/* FIXME - crude hack to resolve undefined global. This function is
- part of support for corefiles, which is not yet implemented. */
+/* Various things we might complain about... */
-unsigned int
-DEFUN(register_addr, (regno, blockend),
- int regno AND
- int blockend)
-{
- error ("Fetching registers from corefiles unimplemented.");
-}
-#endif
+struct complaint section_info_complaint =
+ {"elf/stab section information %s without a preceding file symbol", 0, 0};
+
+struct complaint section_info_dup_complaint =
+ {"duplicated elf/stab section information for %s", 0, 0};
+
+struct complaint stab_info_mismatch_complaint =
+ {"elf/stab section information missing for %s", 0, 0};
+
+struct complaint stab_info_questionable_complaint =
+ {"elf/stab section information questionable for %s", 0, 0};
+
+static void
+elf_symfile_init PARAMS ((struct objfile *));
+
+static void
+elf_new_init PARAMS ((struct objfile *));
+
+static void
+elf_symfile_read PARAMS ((struct objfile *, struct section_offsets *, int));
+
+static void
+elf_symfile_finish PARAMS ((struct objfile *));
+
+static void
+elf_symtab_read PARAMS ((bfd *, CORE_ADDR, struct objfile *));
+
+static void
+free_elfinfo PARAMS ((PTR));
+
+static struct section_offsets *
+elf_symfile_offsets PARAMS ((struct objfile *, CORE_ADDR));
+
+static void
+record_minimal_symbol_and_info PARAMS ((char *, CORE_ADDR,
+ enum minimal_symbol_type, char *,
+ struct objfile *));
+
+static void
+elf_locate_sections PARAMS ((bfd *, asection *, PTR));
/* We are called once per section from elf_symfile_read. We
need to examine each section we are passed, check to see
knowledge of DWARF (by design, so any debugging format can be
used).
+ We also recognize the ".stab" sections used by the Sun compilers
+ released with Solaris 2.
+
FIXME: The section names should not be hardwired strings. */
static void
-DEFUN(elf_locate_sections, (abfd, sectp, ei),
- bfd *abfd AND
- asection *sectp AND
- struct elfinfo *ei)
+elf_locate_sections (ignore_abfd, sectp, eip)
+ bfd *ignore_abfd;
+ asection *sectp;
+ PTR eip;
{
+ register struct elfinfo *ei;
+
+ ei = (struct elfinfo *) eip;
if (STREQ (sectp -> name, ".debug"))
{
ei -> dboffset = sectp -> filepos;
- ei -> dbsize = sectp -> size;
+ ei -> dbsize = bfd_get_section_size_before_reloc (sectp);
}
else if (STREQ (sectp -> name, ".line"))
{
ei -> lnoffset = sectp -> filepos;
- ei -> lnsize = sectp -> size;
+ ei -> lnsize = bfd_get_section_size_before_reloc (sectp);
+ }
+ else if (STREQ (sectp -> name, ".stab"))
+ {
+ ei -> stabsect = sectp;
+ }
+ else if (STREQ (sectp -> name, ".stab.index"))
+ {
+ ei -> stabindexsect = sectp;
+ }
+}
+
+#if 0 /* Currently unused */
+
+char *
+elf_interpreter (abfd)
+ bfd *abfd;
+{
+ sec_ptr interp_sec;
+ unsigned size;
+ char *interp = NULL;
+
+ interp_sec = bfd_get_section_by_name (abfd, ".interp");
+ if (interp_sec)
+ {
+ size = bfd_section_size (abfd, interp_sec);
+ interp = alloca (size);
+ if (bfd_get_section_contents (abfd, interp_sec, interp, (file_ptr)0,
+ size))
+ {
+ interp = savestring (interp, size - 1);
+ }
+ else
+ {
+ interp = NULL;
+ }
+ }
+ return (interp);
+}
+
+#endif
+
+static void
+record_minimal_symbol_and_info (name, address, ms_type, info, objfile)
+ char *name;
+ CORE_ADDR address;
+ enum minimal_symbol_type ms_type;
+ char *info; /* FIXME, is this really char *? */
+ struct objfile *objfile;
+{
+ name = obsavestring (name, strlen (name), &objfile -> symbol_obstack);
+ prim_record_minimal_symbol_and_info (name, address, ms_type, info, -1);
+}
+
+/*
+
+LOCAL FUNCTION
+
+ elf_symtab_read -- read the symbol table of an ELF file
+
+SYNOPSIS
+
+ void elf_symtab_read (bfd *abfd, CORE_ADDR addr,
+ struct objfile *objfile)
+
+DESCRIPTION
+
+ Given an open bfd, a base address to relocate symbols to, and a
+ flag that specifies whether or not this bfd is for an executable
+ or not (may be shared library for example), add all the global
+ function and data symbols to the minimal symbol table.
+
+ In stabs-in-ELF, as implemented by Sun, there are some local symbols
+ defined in the ELF symbol table, which can be used to locate
+ the beginnings of sections from each ".o" file that was linked to
+ form the executable objfile. We gather any such info and record it
+ in data structures hung off the objfile's private data.
+
+*/
+
+static void
+elf_symtab_read (abfd, addr, objfile)
+ bfd *abfd;
+ CORE_ADDR addr;
+ struct objfile *objfile;
+{
+ unsigned int storage_needed;
+ asymbol *sym;
+ asymbol **symbol_table;
+ unsigned int number_of_symbols;
+ unsigned int i;
+ int index;
+ struct cleanup *back_to;
+ CORE_ADDR symaddr;
+ enum minimal_symbol_type ms_type;
+ /* If sectinfo is nonNULL, it contains section info that should end up
+ filed in the objfile. */
+ struct stab_section_info *sectinfo = NULL;
+ /* If filesym is nonzero, it points to a file symbol, but we haven't
+ seen any section info for it yet. */
+ asymbol *filesym = 0;
+ struct dbx_symfile_info *dbx = (struct dbx_symfile_info *)
+ objfile->sym_private;
+ unsigned long size;
+
+ storage_needed = get_symtab_upper_bound (abfd);
+ if (storage_needed > 0)
+ {
+ symbol_table = (asymbol **) xmalloc (storage_needed);
+ back_to = make_cleanup (free, symbol_table);
+ number_of_symbols = bfd_canonicalize_symtab (abfd, symbol_table);
+ for (i = 0; i < number_of_symbols; i++)
+ {
+ sym = symbol_table[i];
+ if (sym -> name == NULL || *sym -> name == '\0')
+ {
+ /* Skip names that don't exist (shouldn't happen), or names
+ that are null strings (may happen). */
+ continue;
+ }
+ if (sym -> flags & BSF_FILE)
+ {
+ /* STT_FILE debugging symbol that helps stabs-in-elf debugging.
+ Chain any old one onto the objfile; remember new sym. */
+ if (sectinfo != NULL)
+ {
+ sectinfo -> next = dbx -> stab_section_info;
+ dbx -> stab_section_info = sectinfo;
+ sectinfo = NULL;
+ }
+ filesym = sym;
+ }
+ else if (sym -> flags & (BSF_GLOBAL | BSF_LOCAL | BSF_WEAK))
+ {
+ /* Select global/local/weak symbols. Note that bfd puts abs
+ symbols in their own section, so all symbols we are
+ interested in will have a section. */
+ /* Bfd symbols are section relative. */
+ symaddr = sym -> value + sym -> section -> vma;
+ /* Relocate all non-absolute symbols by base address. */
+ if (sym -> section != &bfd_abs_section)
+ {
+ symaddr += addr;
+ }
+ /* For non-absolute symbols, use the type of the section
+ they are relative to, to intuit text/data. Bfd provides
+ no way of figuring this out for absolute symbols. */
+ if (sym -> section == &bfd_abs_section)
+ {
+ ms_type = mst_abs;
+ }
+ else if (sym -> section -> flags & SEC_CODE)
+ {
+ if (sym -> flags & BSF_GLOBAL)
+ {
+ ms_type = mst_text;
+ }
+ else if (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
+ 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_DATA)
+ {
+ if (sym -> flags & BSF_GLOBAL)
+ {
+ if (sym -> section -> flags & SEC_HAS_CONTENTS)
+ {
+ ms_type = mst_data;
+ }
+ else
+ {
+ ms_type = mst_bss;
+ }
+ }
+ else if (sym -> flags & BSF_LOCAL)
+ {
+ /* Named Local variable in a Data section. Check its
+ name for stabs-in-elf. The STREQ macro checks the
+ first character inline, so we only actually do a
+ strcmp function call on names that start with 'B'
+ or 'D' */
+ index = SECT_OFF_MAX;
+ if (STREQ ("Bbss.bss", sym -> name))
+ {
+ index = SECT_OFF_BSS;
+ }
+ else if (STREQ ("Ddata.data", sym -> name))
+ {
+ index = SECT_OFF_DATA;
+ }
+ else if (STREQ ("Drodata.rodata", sym -> name))
+ {
+ index = SECT_OFF_RODATA;
+ }
+ if (index != SECT_OFF_MAX)
+ {
+ /* Found a special local symbol. Allocate a
+ sectinfo, if needed, and fill it in. */
+ if (sectinfo == NULL)
+ {
+ sectinfo = (struct stab_section_info *)
+ xmmalloc (objfile -> md, sizeof (*sectinfo));
+ memset ((PTR) sectinfo, 0, sizeof (*sectinfo));
+ if (filesym == NULL)
+ {
+ complain (§ion_info_complaint,
+ sym -> name);
+ }
+ else
+ {
+ sectinfo -> filename =
+ (char *) filesym -> name;
+ }
+ }
+ if (sectinfo -> sections[index] != 0)
+ {
+ complain (§ion_info_dup_complaint,
+ sectinfo -> filename);
+ }
+ /* Bfd symbols are section relative. */
+ symaddr = sym -> value + sym -> section -> vma;
+ /* Relocate non-absolute symbols by base address. */
+ if (sym -> section != &bfd_abs_section)
+ {
+ symaddr += addr;
+ }
+ sectinfo -> sections[index] = symaddr;
+ /* The special local symbols don't go in the
+ minimal symbol table, so ignore this one. */
+ continue;
+ }
+ /* Not a special stabs-in-elf symbol, do regular
+ symbol processing. */
+ if (sym -> section -> flags & SEC_HAS_CONTENTS)
+ {
+ 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. */
+ }
+ /* Pass symbol size field in via BFD. FIXME!!! */
+ size = ((elf_symbol_type *) sym) -> internal_elf_sym.st_size;
+ record_minimal_symbol_and_info ((char *) sym -> name, symaddr,
+ ms_type, (PTR) size, objfile);
+ }
+ }
+ do_cleanups (back_to);
}
}
We have been initialized by a call to elf_symfile_init, which
currently does nothing.
- ADDR is the address relative to which the symbols in it are (e.g.
- the base address of the text segment).
+ SECTION_OFFSETS is a set of offsets to apply to relocate the symbols
+ in each section. We simplify it down to a single offset for all
+ symbols. FIXME.
MAINLINE is true if we are reading the main symbol
table (as opposed to a shared lib or dynamically loaded file).
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. The function dwarf_psymtab_to_symtab() is the function that
- does this for DWARF symbols. */
+ for real.
+
+ We look for sections with specific names, to tell us what debug
+ format to look for: FIXME!!!
+
+ dwarf_build_psymtabs() builds psymtabs for DWARF symbols;
+ elfstab_build_psymtabs() handles STABS symbols.
+
+ 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
-DEFUN(elf_symfile_read, (sf, addr, mainline),
- struct sym_fns *sf AND
- CORE_ADDR addr AND
- int mainline)
+elf_symfile_read (objfile, section_offsets, mainline)
+ struct objfile *objfile;
+ struct section_offsets *section_offsets;
+ int mainline;
{
- bfd *abfd = sf -> sym_bfd;
+ bfd *abfd = objfile->obfd;
struct elfinfo ei;
+ struct cleanup *back_to;
+ CORE_ADDR offset;
+
+ init_minimal_symbol_collection ();
+ back_to = make_cleanup (discard_minimal_symbols, 0);
- bfd_map_over_sections (abfd, elf_locate_sections, &ei);
+ memset ((char *) &ei, 0, sizeof (ei));
+
+ /* Allocate struct to keep track of the symfile */
+ objfile->sym_private = (PTR)
+ xmmalloc (objfile -> md, sizeof (struct dbx_symfile_info));
+ memset ((char *) objfile->sym_private, 0, sizeof (struct dbx_symfile_info));
+ make_cleanup (free_elfinfo, (PTR) objfile);
+
+ /* Process the normal ELF symbol table first. This may write some
+ chain of info into the dbx_symfile_info in objfile->sym_private,
+ which can later be used by elfstab_offset_sections. */
+
+ /* FIXME, should take a section_offsets param, not just an offset. */
+ offset = ANOFFSET (section_offsets, 0);
+ elf_symtab_read (abfd, offset, objfile);
+
+ /* Now process debugging information, which is contained in
+ special ELF sections. We first have to find them... */
+
+ bfd_map_over_sections (abfd, elf_locate_sections, (PTR) &ei);
if (ei.dboffset && ei.lnoffset)
{
- addr = 0; /* FIXME: force address base to zero for now */
- dwarf_build_psymtabs (fileno ((FILE *)(abfd -> iostream)),
- bfd_get_filename (abfd),
- addr, mainline,
+ /* DWARF sections */
+ dwarf_build_psymtabs (objfile,
+ section_offsets, mainline,
ei.dboffset, ei.dbsize,
ei.lnoffset, ei.lnsize);
}
- if (!partial_symtab_list)
+ if (ei.stabsect)
+ {
+ /* STABS sections */
+
+ /* FIXME: Sun didn't really know how to implement this well.
+ They made .stab sections that don't point to the .stabstr
+ section with the sh_link field. BFD doesn't make string table
+ sections visible to the caller. So we have to search the
+ ELF section table, not the BFD section table, for the string
+ table. */
+ struct elf32_internal_shdr *elf_sect;
+
+ elf_sect = bfd_elf_find_section (abfd, ".stabstr");
+ if (elf_sect)
+ elfstab_build_psymtabs (objfile,
+ section_offsets,
+ mainline,
+ ei.stabsect->filepos, /* .stab offset */
+ bfd_get_section_size_before_reloc (ei.stabsect),/* .stab size */
+ (file_ptr) elf_sect->sh_offset, /* .stabstr offset */
+ elf_sect->sh_size); /* .stabstr size */
+ }
+
+ if (!have_partial_symbols ())
{
wrap_here ("");
printf_filtered ("(no debugging symbols found)...");
wrap_here ("");
}
+
+ /* Install any minimal symbols that have been collected as the current
+ minimal symbols for this objfile. */
+
+ install_minimal_symbols (objfile);
+
+ do_cleanups (back_to);
+}
+
+/* This cleans up the objfile's sym_private pointer, and the chain of
+ stab_section_info's, that might be dangling from it. */
+
+static void
+free_elfinfo (objp)
+ PTR objp;
+{
+ struct objfile *objfile = (struct objfile *)objp;
+ struct dbx_symfile_info *dbxinfo = (struct dbx_symfile_info *)
+ objfile->sym_private;
+ struct stab_section_info *ssi, *nssi;
+
+ ssi = dbxinfo->stab_section_info;
+ while (ssi)
+ {
+ nssi = ssi->next;
+ mfree (objfile->md, ssi);
+ ssi = nssi;
+ }
+
+ dbxinfo->stab_section_info = 0; /* Just say No mo info about this. */
}
+
/* 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).
- For now at least, we have nothing in particular to do, so this function is
- just a stub. */
+ We reinitialize buildsym, since we may be reading stabs from an ELF file. */
+
+static void
+elf_new_init (ignore)
+ struct objfile *ignore;
+{
+ stabsread_new_init ();
+ buildsym_new_init ();
+}
+
+/* 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
-DEFUN_VOID (elf_new_init)
+elf_symfile_finish (objfile)
+ struct objfile *objfile;
{
+ if (objfile -> sym_private != NULL)
+ {
+ mfree (objfile -> md, objfile -> sym_private);
+ }
}
/* ELF specific initialization routine for reading symbols.
just a stub. */
static void
-DEFUN(elf_symfile_init, (sf),
- struct sym_fns *sf)
+elf_symfile_init (ignore)
+ struct objfile *ignore;
+{
+}
+
+/* ELF specific parsing routine for section offsets.
+
+ Plain and simple for now. */
+
+static
+struct section_offsets *
+elf_symfile_offsets (objfile, addr)
+ struct objfile *objfile;
+ CORE_ADDR addr;
{
+ struct section_offsets *section_offsets;
+ int i;
+
+ section_offsets = (struct section_offsets *)
+ obstack_alloc (&objfile -> psymbol_obstack,
+ sizeof (struct section_offsets) +
+ sizeof (section_offsets->offsets) * (SECT_OFF_MAX-1));
+
+ for (i = 0; i < SECT_OFF_MAX; i++)
+ ANOFFSET (section_offsets, i) = addr;
+
+ return section_offsets;
}
+\f
+/* When handling an ELF file that contains Sun STABS debug info,
+ some of the debug info is relative to the particular chunk of the
+ section that was generated in its individual .o file. E.g.
+ offsets to static variables are relative to the start of the data
+ segment *for that module before linking*. This information is
+ painfully squirreled away in the ELF symbol table as local symbols
+ with wierd names. Go get 'em when needed. */
+
+void
+elfstab_offset_sections (objfile, pst)
+ struct objfile *objfile;
+ struct partial_symtab *pst;
+{
+ char *filename = pst->filename;
+ struct dbx_symfile_info *dbx = (struct dbx_symfile_info *)
+ objfile->sym_private;
+ struct stab_section_info *maybe = dbx->stab_section_info;
+ struct stab_section_info *questionable = 0;
+ int i;
+ char *p;
+
+ /* The ELF symbol info doesn't include path names, so strip the path
+ (if any) from the psymtab filename. */
+ while (0 != (p = strchr (filename, '/')))
+ filename = p+1;
+
+ /* FIXME: This linear search could speed up significantly
+ if it was chained in the right order to match how we search it,
+ and if we unchained when we found a match. */
+ for (; maybe; maybe = maybe->next)
+ {
+ if (filename[0] == maybe->filename[0]
+ && STREQ (filename, maybe->filename))
+ {
+ /* We found a match. But there might be several source files
+ (from different directories) with the same name. */
+ if (0 == maybe->found)
+ break;
+ questionable = maybe; /* Might use it later. */
+ }
+ }
+
+ if (maybe == 0 && questionable != 0)
+ {
+ complain (&stab_info_questionable_complaint, filename);
+ maybe = questionable;
+ }
+ if (maybe)
+ {
+ /* Found it! Allocate a new psymtab struct, and fill it in. */
+ maybe->found++;
+ pst->section_offsets = (struct section_offsets *)
+ obstack_alloc (&objfile -> psymbol_obstack,
+ sizeof (struct section_offsets) +
+ sizeof (pst->section_offsets->offsets) * (SECT_OFF_MAX-1));
+
+ for (i = 0; i < SECT_OFF_MAX; i++)
+ ANOFFSET (pst->section_offsets, i) = maybe->sections[i];
+ return;
+ }
+
+ /* We were unable to find any offsets for this file. Complain. */
+ if (dbx->stab_section_info) /* If there *is* any info, */
+ complain (&stab_info_mismatch_complaint, filename);
+}
\f
/* Register that we are able to handle ELF object file formats and DWARF
debugging formats.
use "elf" in the same sense as "a.out" or "coff", to imply both the ELF
object file format and the DWARF debugging format. */
-static struct sym_fns elf_sym_fns = {
+static struct sym_fns elf_sym_fns =
+{
"elf", /* sym_name: name or name prefix of BFD target type */
3, /* sym_namelen: number of significant sym_name chars */
elf_new_init, /* sym_new_init: init anything gbl to entire symtab */
elf_symfile_init, /* sym_init: read initial info, setup for sym_read() */
elf_symfile_read, /* sym_read: read a symbol file into symtab */
- NULL, /* sym_bfd: accessor for symbol file being read */
- NULL, /* sym_private: sym_init & sym_read shared info */
+ elf_symfile_finish, /* sym_finish: finished with file, cleanup */
+ elf_symfile_offsets, /* sym_offsets: Translate ext. to int. relocation */
NULL /* next: pointer to next struct sym_fns */
};
void
-DEFUN_VOID (_initialize_elfread)
+_initialize_elfread ()
{
add_symtab_fns (&elf_sym_fns);
}
projects / binutils.git / blobdiff