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-rw-r--r--bfd/ChangeLog22
-rw-r--r--bfd/pdp11.c155
2 files changed, 146 insertions, 31 deletions
diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index f88e5e8..e99de6d 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,5 +1,27 @@
2020-06-04 Stephen Casner <casner@acm.org>
+ Extend pdp11-aout symbol table format to accommodate .stab
+ symbols and implement correct handling of them.
+
+ * pdp11.c (pdp11_external_nlist): Repurposed e_unused to e_desc.
+ (N_STAB, is_stab): Needed new function is_stab to disambiguate
+ normal vs. .stab symbol table type values, replacing N_STAB mask.
+ (translate_from_native_sym_flags): Determine correct section for
+ different .stab types.
+ (translate_to_native_sym_flags): Leave .stab types intact.
+ (translate_symbol_table): Error if symbol indicates overlay;
+ store desc field from .stab symbols.
+ (write_syms): Output desc field with symbol.
+ (aout_link_check_ar_symbols): Skip .stab symbols.
+ (aout_link_add_symbols): Correctly distinguish .stab symbols.
+ (aout_link_write_other_symbol): Write 0 for desk and ovly fields.
+ (aout_link_write_symbols): Write 0 for desk and ovly fields;
+ correctly distinguish .stab symbols and select calculate their
+ section and value; and copy desc and ovly fields from input symbol
+ to output symbol.
+
+2020-06-04 Stephen Casner <casner@acm.org>
+
* aoutx.h (translate_symbol_table): Comment had external and
internal swapped.
* pdp11.c (translate_symbol_table): Likewise.
diff --git a/bfd/pdp11.c b/bfd/pdp11.c
index e436374..2eca67c 100644
--- a/bfd/pdp11.c
+++ b/bfd/pdp11.c
@@ -22,7 +22,9 @@
/* BFD backend for PDP-11, running 2.11BSD in particular.
This file was hacked up by looking hard at the existing vaxnetbsd
- back end and the header files in 2.11BSD.
+ back end and the header files in 2.11BSD. The symbol table format
+ of 2.11BSD has been extended to accommodate .stab symbols. See
+ struct pdp11_external_nlist below for details.
TODO
* support for V7 file formats
@@ -101,10 +103,23 @@ struct pdp11_external_exec
#define A_FLAG_RELOC_STRIPPED 0x0001
+/* The following struct defines the format of an entry in the object file
+ symbol table. In the original 2.11BSD struct the index into the string
+ table is stored as a long, but the PDP11 C convention for storing a long in
+ memory placed the most significant word first even though the bytes within a
+ word are stored least significant first. So here the string table index is
+ considered to be just 16 bits and the first two bytes of the struct were
+ previously named e_unused. To extend the symbol table format to accommodate
+ .stab symbols, the e_unused bytes are renamed e_desc to store the desc field
+ of the .stab symbol. The GDP Project's STABS document says that the "other"
+ field is almost always unused and can be set to zero; the only nonzero cases
+ identified were for stabs in their own sections, which does not apply for
+ pdp11 a.out format, and for a special case of GNU Modula2 which is not
+ supported for the PDP11. */
#define external_nlist pdp11_external_nlist
struct pdp11_external_nlist
{
- bfd_byte e_unused[2]; /* Unused. */
+ bfd_byte e_desc[2]; /* The desc field for .stab symbols, else 0. */
bfd_byte e_strx[2]; /* Index into string table of name. */
bfd_byte e_type[1]; /* Type of symbol. */
bfd_byte e_ovly[1]; /* Overlay number. */
@@ -151,6 +166,13 @@ static bfd_boolean MY(write_object_contents) (bfd *);
#include "aout/stab_gnu.h"
#include "aout/ar.h"
+/* The symbol type numbers for the 16-bit a.out format from 2.11BSD differ from
+ those defined in aout64.h so we must redefine them here. N_EXT changes from
+ 0x01 to 0x20 which creates a conflict with some .stab values, in particular
+ between undefined externals (N_UNDF+N_EXT) vs. global variables (N_GYSM) and
+ between external bss symbols (N_BSS+N_EXT) vs. function names (N_FUN). We
+ disambiguate those conflicts with a hack in is_stab() to look for the ':' in
+ the global variable or function name string. */
#undef N_TYPE
#undef N_UNDF
#undef N_ABS
@@ -170,7 +192,12 @@ static bfd_boolean MY(write_object_contents) (bfd *);
#define N_REG 0x14 /* Register symbol. */
#define N_FN 0x1f /* File name. */
#define N_EXT 0x20 /* External flag. */
-#define N_STAB 0xc0 /* Not relevant; modified aout64.h's 0xe0 to avoid N_EXT. */
+/* Type numbers from .stab entries that could conflict:
+ N_GSYM 0x20 Global variable [conflict with external undef]
+ N_FNAME 0x22 Function name (for BSD Fortran) [ignored]
+ N_FUN 0x24 Function name [conflict with external BSS]
+ N_NOMAP 0x34 No DST map for sym. [ext. reg. doesn't exist]
+*/
#define RELOC_SIZE 2
@@ -300,6 +327,19 @@ NAME (aout, reloc_name_lookup) (bfd *abfd ATTRIBUTE_UNUSED,
return NULL;
}
+/* Disambiguate conflicts between normal symbol types and .stab symbol types
+ (undefined externals N_UNDF+N_EXT vs. global variables N_GYSM and external
+ bss symbols N_BSS+N_EXT vs. function names N_FUN) with a hack to look for
+ the ':' in the global variable or function name string. */
+
+static int
+is_stab (int type, const char *name)
+{
+ if (type == N_GSYM || type == N_FUN)
+ return (index(name, ':') != NULL);
+ return (type > N_FUN);
+}
+
static int
pdp11_aout_write_headers (bfd *abfd, struct internal_exec *execp)
{
@@ -1325,7 +1365,7 @@ translate_from_native_sym_flags (bfd *abfd,
{
flagword visible;
- if (cache_ptr->type == N_FN)
+ if (is_stab (cache_ptr->type, cache_ptr->symbol.name))
{
asection *sec;
@@ -1333,20 +1373,25 @@ translate_from_native_sym_flags (bfd *abfd,
cache_ptr->symbol.flags = BSF_DEBUGGING;
/* Work out the symbol section. */
- switch (cache_ptr->type & N_TYPE)
+ switch (cache_ptr->type)
{
- case N_TEXT:
+ case N_SO:
+ case N_SOL:
+ case N_FUN:
+ case N_ENTRY:
+ case N_SLINE:
case N_FN:
sec = obj_textsec (abfd);
break;
- case N_DATA:
+ case N_STSYM:
+ case N_DSLINE:
sec = obj_datasec (abfd);
break;
- case N_BSS:
+ case N_LCSYM:
+ case N_BSLINE:
sec = obj_bsssec (abfd);
break;
default:
- case N_ABS:
sec = bfd_abs_section_ptr;
break;
}
@@ -1418,10 +1463,12 @@ translate_to_native_sym_flags (bfd *abfd,
bfd_vma value = cache_ptr->value;
asection *sec;
bfd_vma off;
+ const char *name = cache_ptr->name != NULL ? cache_ptr->name : "*unknown*";
/* Mask out any existing type bits in case copying from one section
to another. */
- sym_pointer->e_type[0] &= ~N_TYPE;
+ if (!is_stab (sym_pointer->e_type[0], name))
+ sym_pointer->e_type[0] &= ~N_TYPE;
sec = bfd_asymbol_section (cache_ptr);
off = 0;
@@ -1433,7 +1480,7 @@ translate_to_native_sym_flags (bfd *abfd,
_bfd_error_handler
/* xgettext:c-format */
(_("%pB: can not represent section for symbol `%s' in a.out object file format"),
- abfd, cache_ptr->name != NULL ? cache_ptr->name : "*unknown*");
+ abfd, name);
bfd_set_error (bfd_error_nonrepresentable_section);
return FALSE;
}
@@ -1511,6 +1558,7 @@ NAME (aout, translate_symbol_table) (bfd *abfd,
for (; ext < ext_end; ext++, in++)
{
bfd_vma x;
+ int ovly;
x = GET_WORD (abfd, ext->e_strx);
in->symbol.the_bfd = abfd;
@@ -1533,9 +1581,19 @@ NAME (aout, translate_symbol_table) (bfd *abfd,
return FALSE;
}
+ ovly = H_GET_8 (abfd, ext->e_ovly);
+ if (ovly != 0)
+ {
+ _bfd_error_handler
+ (_("%pB: symbol indicates overlay (not supported)"), abfd);
+ bfd_set_error (bfd_error_bad_value);
+ return FALSE;
+ }
+
in->symbol.value = GET_WORD (abfd, ext->e_value);
- /* TODO: is 0 a safe value here? */
- in->desc = 0;
+ /* e_desc is zero for normal symbols but for .stab symbols it
+ carries the desc field in our extended 2.11BSD format. */
+ in->desc = H_GET_16 (abfd, ext->e_desc);
in->other = 0;
in->type = H_GET_8 (abfd, ext->e_type);
in->symbol.udata.p = NULL;
@@ -1686,23 +1744,27 @@ NAME (aout, write_syms) (bfd *abfd)
bfd_size_type indx;
struct external_nlist nsp;
- PUT_WORD (abfd, 0, nsp.e_unused);
-
indx = add_to_stringtab (abfd, strtab, g->name, FALSE);
if (indx == (bfd_size_type) -1)
goto error_return;
PUT_WORD (abfd, indx, nsp.e_strx);
if (bfd_asymbol_flavour(g) == abfd->xvec->flavour)
- H_PUT_8 (abfd, aout_symbol(g)->type, nsp.e_type);
+ {
+ H_PUT_16 (abfd, aout_symbol (g)->desc, nsp.e_desc);
+ H_PUT_8 (abfd, 0, nsp.e_ovly);
+ H_PUT_8 (abfd, aout_symbol (g)->type, nsp.e_type);
+ }
else
- H_PUT_8 (abfd, 0, nsp.e_type);
+ {
+ H_PUT_16 (abfd, 0, nsp.e_desc);
+ H_PUT_8 (abfd, 0, nsp.e_ovly);
+ H_PUT_8 (abfd, 0, nsp.e_type);
+ }
if (! translate_to_native_sym_flags (abfd, g, &nsp))
goto error_return;
- H_PUT_8 (abfd, 0, nsp.e_ovly);
-
if (bfd_bwrite ((void *)&nsp, (bfd_size_type) EXTERNAL_NLIST_SIZE, abfd)
!= EXTERNAL_NLIST_SIZE)
goto error_return;
@@ -2643,17 +2705,17 @@ aout_link_check_ar_symbols (bfd *abfd,
for (; p < pend; p++)
{
int type = H_GET_8 (abfd, p->e_type);
- const char *name;
+ const char *name = strings + GET_WORD (abfd, p->e_strx);
struct bfd_link_hash_entry *h;
/* Ignore symbols that are not externally visible. This is an
optimization only, as we check the type more thoroughly
below. */
if ((type & N_EXT) == 0
+ || is_stab(type, name)
|| type == N_FN)
continue;
- name = strings + GET_WORD (abfd, p->e_strx);
h = bfd_link_hash_lookup (info->hash, name, FALSE, FALSE, TRUE);
/* We are only interested in symbols that are currently
@@ -2863,6 +2925,10 @@ aout_link_add_symbols (bfd *abfd, struct bfd_link_info *info)
type = H_GET_8 (abfd, p->e_type);
+ /* Ignore debugging symbols. */
+ if (is_stab(type, name))
+ continue;
+
/* PR 19629: Corrupt binaries can contain illegal string offsets. */
if (GET_WORD (abfd, p->e_strx) >= obj_aout_external_string_size (abfd))
return FALSE;
@@ -2873,8 +2939,8 @@ aout_link_add_symbols (bfd *abfd, struct bfd_link_info *info)
switch (type)
{
default:
- /* Anything else should be a debugging symbol. */
- BFD_ASSERT ((type & N_STAB) != 0);
+ /* Shouldn't be any types not covered. */
+ BFD_ASSERT (0);
continue;
case N_UNDF:
@@ -3077,12 +3143,14 @@ aout_link_write_other_symbol (struct bfd_hash_entry *bh, void *data)
}
H_PUT_8 (output_bfd, type, outsym.e_type);
+ H_PUT_8 (output_bfd, 0, outsym.e_ovly);
indx = add_to_stringtab (output_bfd, flaginfo->strtab, h->root.root.string,
FALSE);
if (indx == (bfd_size_type) -1)
/* FIXME: No way to handle errors. */
abort ();
+ PUT_WORD (output_bfd, 0, outsym.e_desc);
PUT_WORD (output_bfd, indx, outsym.e_strx);
PUT_WORD (output_bfd, val, outsym.e_value);
@@ -4097,6 +4165,8 @@ aout_link_write_symbols (struct aout_final_link_info *flaginfo, bfd *input_bfd)
&& discard != discard_all)
{
H_PUT_8 (output_bfd, N_TEXT, outsym->e_type);
+ H_PUT_8 (output_bfd, 0, outsym->e_ovly);
+ H_PUT_16 (output_bfd, 0, outsym->e_desc);
strtab_index = add_to_stringtab (output_bfd, flaginfo->strtab,
bfd_get_filename (input_bfd), FALSE);
if (strtab_index == (bfd_size_type) -1)
@@ -4210,7 +4280,7 @@ aout_link_write_symbols (struct aout_final_link_info *flaginfo, bfd *input_bfd)
case strip_none:
break;
case strip_debugger:
- if ((type & N_STAB) != 0)
+ if (is_stab (type, name))
skip = TRUE;
break;
case strip_some:
@@ -4230,7 +4300,33 @@ aout_link_write_symbols (struct aout_final_link_info *flaginfo, bfd *input_bfd)
}
/* Get the value of the symbol. */
- if ((type & N_TYPE) == N_TEXT
+ if (is_stab (type, name))
+ {
+ switch (type)
+ {
+ default:
+ symsec = bfd_abs_section_ptr;
+ break;
+ case N_SO:
+ case N_SOL:
+ case N_FUN:
+ case N_ENTRY:
+ case N_SLINE:
+ case N_FN:
+ symsec = obj_textsec (input_bfd);
+ break;
+ case N_STSYM:
+ case N_DSLINE:
+ symsec = obj_datasec (input_bfd);
+ break;
+ case N_LCSYM:
+ case N_BSLINE:
+ symsec = obj_bsssec (input_bfd);
+ break;
+ }
+ val = GET_WORD (input_bfd, sym->e_value);
+ }
+ else if ((type & N_TYPE) == N_TEXT
|| type == N_WEAKT)
symsec = obj_textsec (input_bfd);
else if ((type & N_TYPE) == N_DATA
@@ -4258,11 +4354,6 @@ aout_link_write_symbols (struct aout_final_link_info *flaginfo, bfd *input_bfd)
val = GET_WORD (input_bfd, sym->e_value);
symsec = NULL;
}
- else if ((type & N_STAB) != 0)
- {
- val = GET_WORD (input_bfd, sym->e_value);
- symsec = NULL;
- }
else
{
/* If we get here with an indirect symbol, it means that
@@ -4376,7 +4467,7 @@ aout_link_write_symbols (struct aout_final_link_info *flaginfo, bfd *input_bfd)
case discard_sec_merge:
break;
case discard_l:
- if ((type & N_STAB) == 0
+ if (!is_stab (type, name)
&& bfd_is_local_label_name (input_bfd, name))
skip = TRUE;
break;
@@ -4500,6 +4591,8 @@ aout_link_write_symbols (struct aout_final_link_info *flaginfo, bfd *input_bfd)
/* Copy this symbol into the list of symbols we are going to
write out. */
H_PUT_8 (output_bfd, type, outsym->e_type);
+ H_PUT_8 (output_bfd, H_GET_8 (input_bfd, sym->e_ovly), outsym->e_ovly);
+ H_PUT_16 (output_bfd, H_GET_16 (input_bfd, sym->e_desc), outsym->e_desc);
copy = FALSE;
if (! flaginfo->info->keep_memory)
{
generated by cgit v1.1 at 2024-11-30 03:10:41 +0000