RFC: Access TLS symbols without DWARF debuginfo v2

Jan Kratochvil
2006-08-25T20:02:17Z

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Hi,

attached a single unifying/dropping patch those 3 patches before.

2006-08-25 Jan Kratochvil <jan.kratochvil@redhat.com>

* dwarf2loc.c (dwarf_expr_tls_address): Code moved out to
`target_translate_tls_address'.
* target.c (target_translate_tls_address): Moved here.
Provided warnings for TLS `errno' on non-TLS targets.
* target.h (target_translate_tls_address): Moved here.
* eval.c (evaluate_subexp_standard): New `UNOP_MEMVAL_TLS'.
* expprint.c (print_subexp_standard): New `UNOP_MEMVAL_TLS'.
(op_name_standard): New `UNOP_MEMVAL_TLS'.
(dump_subexp_body_standard): New `UNOP_MEMVAL_TLS'.
* expression.h (enum exp_opcode): New `UNOP_MEMVAL_TLS'.
(union exp_element): New `objfile' type.
* parse.c (write_exp_elt_objfile): New `objfile' setter.
(write_exp_msymbol): Support new `UNOP_MEMVAL_TLS'.
(msym_text_tls_symbol_type, msym_data_tls_symbol_type,
msym_unknown_tls_symbol_type, build_parse): New TLS types.
(operator_length_standard): New `UNOP_MEMVAL_TLS'.
* parser-defs.h (write_exp_elt_objfile): New `objfile' setter.
* valops.c (value_at_lazy): Pass control to `value_at_lazy_tls'.
(value_at_lazy_tls): Provide TLS `struct objfile *' storage.
(value_fetch_lazy): Resolve TLS `struct objfile *' storage.
(value_assign): Resolve TLS `struct objfile *' storage.
* value.c (struct value, allocate_value, value_tls_objfile,
set_value_tls_objfile): Provide TLS `struct objfile *' storage.
* value.h (value_tls_objfile, set_value_tls_objfile,
value_at_lazy_tls): Provide TLS `struct objfile *' storage.
* Makefile.in: Updated dependencies.

2006-08-25 Jan Kratochvil <jan.kratochvil@redhat.com>

* gdb.threads/tls-nodebug.c: New file, test TLS symbols on gcc -s.
* gdb.threads/tls-nodebug.exp: New file, test TLS symbols on gcc -s.

On Fri, 25 Aug 2006 05:43:01 +0200, Daniel Jacobowitz wrote:
> First a general note: please include changelogs with patches.

Forgot again, last time, sorry. Isn't there some tool to generate this
changelog type templates from the diff?

> Also in the minor feedback area, updates to included files need to be
> reflected in Makefile.in, and URLs to Red Hat's bugzilla are not appropriate
> for the FSF GDB; if you want to describe the problem, just do so.

Thanks for info, to be followed.
Personal info: That gnatsweb is just unusable, move to Bugzilla, please.

> On Fri, Aug 25, 2006 at 04:13:11AM +0200, Jan Kratochvil wrote:
> > * with -ggdb2 and less "errno" in fact does not exist anywhere as it was
> > compiled to "(*__errno_location ())" and the macro definition is not present.
> > Unfortunately gdb will find the TLS symbol and it will try to access it but
> > as the program has been compiled without -lpthread the TLS base register
> > (%gs on i386) is not setup and it will result in:
> > Cannot access memory at address 0x8
>
> That can't be correct. Every program using glibc references errno.
> If the program can access it, then GDB ought to be able to also.
> In this case, libc.so.6 exports a dynamic TLS symbol named errno.

If I compile code with or without -pthread (on Fedora Core 5) "errno" is never
found in the target (dynamic) executable. "errno" is there only with -ggdb3 as:
DW_MACINFO_define - lineno : 47 macro : errno (*__errno_location ())

Unaware why %gs is not being used in the user code.
%gs-using "errno.h" is available only during glibc compilation. I get only:

8048915: e8 1e fc ff ff call 8048538 <__errno_location@plt>
804891a: 8b 00 mov (%eax),%eax
804891c: 89 04 24 mov %eax,(%esp)

> Did you try this with the patch you posted earlier to access TLS
> without debug info?

Both patches were developed together. Still that
RFC: Ignore TLS symbols for non-TLS programs
gdb-6.5-bz185337-missing-errno-suggestion.patch
had been mostly obsolete by the other one and deprecated after your comments.

> > +++ gdb/minsyms.c 25 Aug 2006 01:42:27 -0000
...
> > +#include "target.h"
>
> This violates the abstraction layers. We're reading the symbols from
> a file. Why should it matter what target we're connected to? In fact,
> we probably aren't connected to a target yet. Decisions about what we
> can access should only be made when we want to access it.

You are right, rewritten by your advice. I had a problem delaying it before as
the TLS `errno' for non-TLS inferior detection had to be written differently.

The trailing part of `target_translate_tls_address' now already contains
gdb-6.5-bz185337-missing-errno-suggestion.patch

> > +/* Test accessing TLS based variable without -lpthread / TLS setup. */
> > +
> > +#include <pthread.h>
> > +
> > +__thread int thread_local = 42;
> > +
> > +int main(void)
> > +{
> > + return 0;
> > +}
>
> It would be legal for main to return the value of thread_local, even
> though it is not linked to pthread.c.

Sorry but I do not understand a reason to do so.

> Oh, and you don't actually need <pthread.h> for this.

Removed.

> > +if {[gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable []] != "" } {
>
> Did you try this? [] should give you a TCL syntax error.

It works, empty command produces empty string.
gdb-unified by '$options', though - thanks.

On Fri, 25 Aug 2006 15:43:16 +0200, Daniel Jacobowitz wrote:
> On Fri, Aug 25, 2006 at 04:13:04AM +0200, Jan Kratochvil wrote:
...
> > Attached patch implements accessing them without the debuginfo suggestions as
> > not always such associatet debuginfo is available. It checks for
> > SYMBOL_BFD_SECTION (msymbol)->flags & SEC_THREAD_LOCAL
> > symbols, implements for them new `UNOP_MEMVAL_TLS' and reuses for them former
> > `dwarf_expr_tls_address'.
...
> Could you explain why you added a new kind of value for this? I'd have
> thought that when we wanted the address of the symbol, we should be
> able to resolve it. So instead of value_at_lazy_tls, we would resolve
> the address using the target. Expressions persist between threads and
> executions, but values shouldn't. That should simplify the code a
> little.

Sorry, I probably do not have such high overview of the code - what code would
you patch to "resolve the address using the target"?

The following text is probably useless:

% I just did not see there any target-specific code needing to be modified
% as former `dwarf_expr_tls_address' covers it nice.
%
% I am aware the TLS-resolving should be done as late as possible as
% linux-thread-db.c providing its target_get_thread_local_address_p () may be
% initialized very late.
%
% The latest possible time is `value_at_lazy_tls' but there is no longer
% available `struct objfile *' for `target_translate_tls_address'.
% So I had to pass such information somehow to `value_at_lazy_tls'.
%
% The target info is `struct objfile *' for `target_translate_tls_address'.
% The source info is `bfd *' in `write_exp_msymbol'.
% I could store `bfd *' (`SYMBOL_BFD_SECTION (msymbol)->owner')
% or `int' (`SYMBOL_BFD_SECTION (msymbol)->owner->id')
% or `struct objfile *' (resolved from `bfd *').
%
% I chose `struct objfile *', so I had to extend `struct value' to store it.
% I would have to extend `struct value' by some field anyway.
% I also had to extend `union exp_element' to store the new type there.
% I would have to extend `union exp_element' even for `bfd *',
% only in the case of chosen `bfd.id' `union exp_element' could be reused.
%
% I do not find much difference how to store this additional information,
% I just did not find a way how to deal without it.

On Fri, 25 Aug 2006 15:47:50 +0200, Daniel Jacobowitz wrote:
> On Thu, Aug 24, 2006 at 11:43:01PM -0400, Daniel Jacobowitz wrote:
> > On Fri, Aug 25, 2006 at 04:13:11AM +0200, Jan Kratochvil wrote:
> > > * with -ggdb2 and less "errno" in fact does not exist anywhere as it was
> > > compiled to "(*__errno_location ())" and the macro definition is not present.
> > > Unfortunately gdb will find the TLS symbol and it will try to access it but
> > > as the program has been compiled without -lpthread the TLS base register
> > > (%gs on i386) is not setup and it will result in:
> > > Cannot access memory at address 0x8
> >
> > That can't be correct. Every program using glibc references errno.
> > If the program can access it, then GDB ought to be able to also.
> > In this case, libc.so.6 exports a dynamic TLS symbol named errno.
> >
> > Did you try this with the patch you posted earlier to access TLS
> > without debug info?
>
> Oh, I see now - that's not enough, you'd also need to implement direct
> DTV lookup in GDB since libthread_db probably can't cope. And that
> might require some fiddling with e.g. the remote protocol, too, to get
> at the result of ps_get_thread_area. Anyway, this is doable, just
> a bit of work.
>
> With your other patch, I hope this would get a more appropriate error,
> like "can't access thread local data"?

I hope this is no longer to be resolved as this patch got dropped.
Sorry but I do not understand `DTV'.

Regads,
Jan

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Index: Makefile.in
===================================================================
RCS file: /cvs/src/src/gdb/Makefile.in,v
retrieving revision 1.840
diff -u -p -r1.840 Makefile.in
--- Makefile.in 22 Aug 2006 19:08:31 -0000 1.840
+++ Makefile.in 25 Aug 2006 19:55:35 -0000
@@ -1977,7 +1977,7 @@ exec.o: exec.c $(defs_h) $(frame_h) $(in
$(xcoffsolib_h) $(observer_h)
expprint.o: expprint.c $(defs_h) $(symtab_h) $(gdbtypes_h) $(expression_h) \
$(value_h) $(language_h) $(parser_defs_h) $(user_regs_h) $(target_h) \
- $(gdb_string_h) $(block_h)
+ $(gdb_string_h) $(block_h) $(objfiles_h)
fbsd-nat.o: fbsd-nat.c $(defs_h) $(gdbcore_h) $(inferior_h) $(regcache_h) \
$(regset_h) $(gdb_assert_h) $(gdb_string_h) $(elf_bfd_h) \
$(fbsd_nat_h)
@@ -2422,7 +2422,7 @@ osabi.o: osabi.c $(defs_h) $(gdb_assert_
parse.o: parse.c $(defs_h) $(gdb_string_h) $(symtab_h) $(gdbtypes_h) \
$(frame_h) $(expression_h) $(value_h) $(command_h) $(language_h) \
$(f_lang_h) $(parser_defs_h) $(gdbcmd_h) $(symfile_h) $(inferior_h) \
- $(doublest_h) $(gdb_assert_h) $(block_h) $(source_h)
+ $(doublest_h) $(gdb_assert_h) $(block_h) $(source_h) $(objfiles_h)
p-exp.o: p-exp.c $(defs_h) $(gdb_string_h) $(expression_h) $(value_h) \
$(parser_defs_h) $(language_h) $(p_lang_h) $(bfd_h) $(symfile_h) \
$(objfiles_h) $(block_h)
@@ -2750,7 +2750,8 @@ symtab.o: symtab.c $(defs_h) $(symtab_h)
$(gdb_stat_h) $(cp_abi_h) $(observer_h)
target.o: target.c $(defs_h) $(gdb_string_h) $(target_h) $(gdbcmd_h) \
$(symtab_h) $(inferior_h) $(bfd_h) $(symfile_h) $(objfiles_h) \
- $(gdb_wait_h) $(dcache_h) $(regcache_h) $(gdb_assert_h) $(gdbcore_h)
+ $(gdb_wait_h) $(dcache_h) $(regcache_h) $(gdb_assert_h) $(gdbcore_h) \
+ $(exceptions_h)
thread.o: thread.c $(defs_h) $(symtab_h) $(frame_h) $(inferior_h) \
$(environ_h) $(value_h) $(target_h) $(gdbthread_h) $(exceptions_h) \
$(command_h) $(gdbcmd_h) $(regcache_h) $(gdb_h) $(gdb_string_h) \
Index: dwarf2loc.c
===================================================================
RCS file: /cvs/src/src/gdb/dwarf2loc.c,v
retrieving revision 1.33
diff -u -p -r1.33 dwarf2loc.c
--- dwarf2loc.c 17 Dec 2005 22:33:59 -0000 1.33
+++ dwarf2loc.c 25 Aug 2006 19:55:36 -0000
@@ -189,86 +189,8 @@ static CORE_ADDR
dwarf_expr_tls_address (void *baton, CORE_ADDR offset)
{
struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton;
- volatile CORE_ADDR addr = 0;

- if (target_get_thread_local_address_p ()
- && gdbarch_fetch_tls_load_module_address_p (current_gdbarch))
- {
- ptid_t ptid = inferior_ptid;
- struct objfile *objfile = debaton->objfile;
- volatile struct gdb_exception ex;
-
- TRY_CATCH (ex, RETURN_MASK_ALL)
- {
- CORE_ADDR lm_addr;
-
- /* Fetch the load module address for this objfile. */
- lm_addr = gdbarch_fetch_tls_load_module_address (current_gdbarch,
- objfile);
- /* If it's 0, throw the appropriate exception. */
- if (lm_addr == 0)
- throw_error (TLS_LOAD_MODULE_NOT_FOUND_ERROR,
- _("TLS load module not found"));
-
- addr = target_get_thread_local_address (ptid, lm_addr, offset);
- }
- /* If an error occurred, print TLS related messages here. Otherwise,
- throw the error to some higher catcher. */
- if (ex.reason < 0)
- {
- int objfile_is_library = (objfile->flags & OBJF_SHARED);
-
- switch (ex.error)
- {
- case TLS_NO_LIBRARY_SUPPORT_ERROR:
- error (_("Cannot find thread-local variables in this thread library."));
- break;
- case TLS_LOAD_MODULE_NOT_FOUND_ERROR:
- if (objfile_is_library)
- error (_("Cannot find shared library `%s' in dynamic"
- " linker's load module list"), objfile->name);
- else
- error (_("Cannot find executable file `%s' in dynamic"
- " linker's load module list"), objfile->name);
- break;
- case TLS_NOT_ALLOCATED_YET_ERROR:
- if (objfile_is_library)
- error (_("The inferior has not yet allocated storage for"
- " thread-local variables in\n"
- "the shared library `%s'\n"
- "for %s"),
- objfile->name, target_pid_to_str (ptid));
- else
- error (_("The inferior has not yet allocated storage for"
- " thread-local variables in\n"
- "the executable `%s'\n"
- "for %s"),
- objfile->name, target_pid_to_str (ptid));
- break;
- case TLS_GENERIC_ERROR:
- if (objfile_is_library)
- error (_("Cannot find thread-local storage for %s, "
- "shared library %s:\n%s"),
- target_pid_to_str (ptid),
- objfile->name, ex.message);
- else
- error (_("Cannot find thread-local storage for %s, "
- "executable file %s:\n%s"),
- target_pid_to_str (ptid),
- objfile->name, ex.message);
- break;
- default:
- throw_exception (ex);
- break;
- }
- }
- }
- /* It wouldn't be wrong here to try a gdbarch method, too; finding
- TLS is an ABI-specific thing. But we don't do that yet. */
- else
- error (_("Cannot find thread-local variables on this target"));
-
- return addr;
+ return target_translate_tls_address (debaton->objfile, offset);
}

/* Evaluate a location description, starting at DATA and with length
Index: eval.c
===================================================================
RCS file: /cvs/src/src/gdb/eval.c,v
retrieving revision 1.63
diff -u -p -r1.63 eval.c
--- eval.c 25 Jul 2006 04:24:50 -0000 1.63
+++ eval.c 25 Aug 2006 19:55:38 -0000
@@ -2019,6 +2019,18 @@ evaluate_subexp_standard (struct type *e
return value_at_lazy (exp->elts[pc + 1].type,
value_as_address (arg1));

+ case UNOP_MEMVAL_TLS:
+ (*pos) += 3;
+ arg1 = evaluate_subexp (expect_type, exp, pos, noside);
+ if (noside == EVAL_SKIP)
+ goto nosideret;
+ if (noside == EVAL_AVOID_SIDE_EFFECTS)
+ return value_zero (exp->elts[pc + 2].type, lval_memory);
+ else
+ return value_at_lazy_tls (exp->elts[pc + 2].type,
+ value_as_address (arg1),
+ exp->elts[pc + 1].objfile);
+
case UNOP_PREINCREMENT:
arg1 = evaluate_subexp (expect_type, exp, pos, noside);
if (noside == EVAL_SKIP || noside == EVAL_AVOID_SIDE_EFFECTS)
Index: expprint.c
===================================================================
RCS file: /cvs/src/src/gdb/expprint.c,v
retrieving revision 1.24
diff -u -p -r1.24 expprint.c
--- expprint.c 7 Aug 2006 03:30:54 -0000 1.24
+++ expprint.c 25 Aug 2006 19:55:39 -0000
@@ -31,6 +31,7 @@
#include "target.h"
#include "gdb_string.h"
#include "block.h"
+#include "objfiles.h"

#ifdef HAVE_CTYPE_H
#include <ctype.h>
@@ -414,6 +415,33 @@ print_subexp_standard (struct expression
fputs_filtered (")", stream);
return;

+ case UNOP_MEMVAL_TLS:
+ (*pos) += 3;
+ if ((int) prec > (int) PREC_PREFIX)
+ fputs_filtered ("(", stream);
+ if (TYPE_CODE (exp->elts[pc + 2].type) == TYPE_CODE_FUNC &&
+ exp->elts[pc + 4].opcode == OP_LONG)
+ {
+ /* We have a minimal symbol fn, probably. It's encoded
+ as a UNOP_MEMVAL (function-type) of an OP_LONG (int, address).
+ Swallow the OP_LONG (including both its opcodes); ignore
+ its type; print the value in the type of the MEMVAL. */
+ (*pos) += 4;
+ val = value_at_lazy (exp->elts[pc + 2].type,
+ (CORE_ADDR) exp->elts[pc + 6].longconst);
+ value_print (val, stream, 0, Val_no_prettyprint);
+ }
+ else
+ {
+ fputs_filtered ("{", stream);
+ type_print (exp->elts[pc + 2].type, "", stream, 0);
+ fputs_filtered ("} ", stream);
+ print_subexp (exp, pos, stream, PREC_PREFIX);
+ }
+ if ((int) prec > (int) PREC_PREFIX)
+ fputs_filtered (")", stream);
+ return;
+
case BINOP_ASSIGN_MODIFY:
opcode = exp->elts[pc + 1].opcode;
(*pos) += 2;
@@ -694,6 +722,8 @@ op_name_standard (enum exp_opcode opcode
return "UNOP_CAST";
case UNOP_MEMVAL:
return "UNOP_MEMVAL";
+ case UNOP_MEMVAL_TLS:
+ return "UNOP_MEMVAL_TLS";
case UNOP_NEG:
return "UNOP_NEG";
case UNOP_LOGICAL_NOT:
@@ -999,6 +1029,16 @@ dump_subexp_body_standard (struct expres
fprintf_filtered (stream, ")");
elt = dump_subexp (exp, stream, elt + 2);
break;
+ case UNOP_MEMVAL_TLS:
+ fprintf_filtered (stream, "TLS type @");
+ gdb_print_host_address (exp->elts[elt + 1].type, stream);
+ fprintf_filtered (stream, " (__thread /* \"%s\" */ ",
+ (exp->elts[elt].objfile == NULL ? "(null)"
+ : exp->elts[elt].objfile->name));
+ type_print (exp->elts[elt + 1].type, NULL, stream, 0);
+ fprintf_filtered (stream, ")");
+ elt = dump_subexp (exp, stream, elt + 3);
+ break;
case OP_TYPE:
fprintf_filtered (stream, "Type @");
gdb_print_host_address (exp->elts[elt].type, stream);
Index: expression.h
===================================================================
RCS file: /cvs/src/src/gdb/expression.h,v
retrieving revision 1.18
diff -u -p -r1.18 expression.h
--- expression.h 17 Dec 2005 22:33:59 -0000 1.18
+++ expression.h 25 Aug 2006 19:55:40 -0000
@@ -234,6 +234,13 @@ enum exp_opcode
following subexpression. */
UNOP_MEMVAL,

+ /* UNOP_MEMVAL_TLS is followed by a `struct objfile' pointer in the next
+ exp_element and a type pointer in the following exp_element.
+ With another UNOP_MEMVAL_TLS at the end, this makes four exp_elements.
+ It casts the contents of the word offsetted by the value of the
+ following subexpression from the TLS specified by `struct objfile'. */
+ UNOP_MEMVAL_TLS,
+
/* UNOP_... operate on one value from a following subexpression
and replace it with a result. They take no immediate arguments. */

@@ -360,6 +367,7 @@ union exp_element
struct type *type;
struct internalvar *internalvar;
struct block *block;
+ struct objfile *objfile;
};

struct expression
Index: parse.c
===================================================================
RCS file: /cvs/src/src/gdb/parse.c,v
retrieving revision 1.53
diff -u -p -r1.53 parse.c
--- parse.c 6 Jul 2006 14:00:48 -0000 1.53
+++ parse.c 25 Aug 2006 19:55:41 -0000
@@ -53,6 +53,7 @@
#include "gdb_assert.h"
#include "block.h"
#include "source.h"
+#include "objfiles.h"

/* Standard set of definitions for printing, dumping, prefixifying,
* and evaluating expressions. */
@@ -219,6 +220,15 @@ write_exp_elt_block (struct block *b)
}

void
+write_exp_elt_objfile (struct objfile *objfile)
+{
+ union exp_element tmp;
+ memset (&tmp, 0, sizeof (union exp_element));
+ tmp.objfile = objfile;
+ write_exp_elt (tmp);
+}
+
+void
write_exp_elt_longcst (LONGEST expelt)
{
union exp_element tmp;
@@ -378,6 +388,9 @@ write_exp_bitstring (struct stoken str)
static struct type *msym_text_symbol_type;
static struct type *msym_data_symbol_type;
static struct type *msym_unknown_symbol_type;
+static struct type *msym_text_tls_symbol_type;
+static struct type *msym_data_tls_symbol_type;
+static struct type *msym_unknown_tls_symbol_type;

void
write_exp_msymbol (struct minimal_symbol *msymbol,
@@ -385,6 +398,8 @@ write_exp_msymbol (struct minimal_symbol
struct type *data_symbol_type)
{
CORE_ADDR addr;
+ int tls = SYMBOL_BFD_SECTION (msymbol)->flags & SEC_THREAD_LOCAL;
+ enum exp_opcode opcode = tls ? UNOP_MEMVAL_TLS : UNOP_MEMVAL;

write_exp_elt_opcode (OP_LONG);
/* Let's make the type big enough to hold a 64-bit address. */
@@ -397,27 +412,49 @@ write_exp_msymbol (struct minimal_symbol

write_exp_elt_opcode (OP_LONG);

- write_exp_elt_opcode (UNOP_MEMVAL);
+ write_exp_elt_opcode (opcode);
+
+ if (opcode == UNOP_MEMVAL_TLS)
+ {
+ bfd *bfd = SYMBOL_BFD_SECTION (msymbol)->owner;
+ struct objfile *ofp;
+
+ ALL_OBJFILES (ofp)
+ if (ofp->obfd == bfd)
+ break;
+ write_exp_elt_objfile (ofp);
+ }
+
switch (msymbol->type)
{
case mst_text:
case mst_file_text:
case mst_solib_trampoline:
- write_exp_elt_type (msym_text_symbol_type);
+ if (tls)
+ write_exp_elt_type (msym_text_tls_symbol_type);
+ else
+ write_exp_elt_type (msym_text_symbol_type);
break;

case mst_data:
case mst_file_data:
case mst_bss:
case mst_file_bss:
- write_exp_elt_type (msym_data_symbol_type);
+ if (tls)
+ write_exp_elt_type (msym_data_tls_symbol_type);
+ else
+ write_exp_elt_type (msym_data_symbol_type);
break;

default:
- write_exp_elt_type (msym_unknown_symbol_type);
+ if (tls)
+ write_exp_elt_type (msym_unknown_tls_symbol_type);
+ else
+ write_exp_elt_type (msym_unknown_symbol_type);
break;
}
- write_exp_elt_opcode (UNOP_MEMVAL);
+
+ write_exp_elt_opcode (opcode);
}
\f
/* Recognize tokens that start with '$'. These include:
@@ -904,6 +941,11 @@ operator_length_standard (struct express
args = 1;
break;

+ case UNOP_MEMVAL_TLS:
+ oplen = 4;
+ args = 1;
+ break;
+
case UNOP_ABS:
case UNOP_CAP:
case UNOP_CHR:
@@ -1341,6 +1383,17 @@ build_parse (void)
init_type (TYPE_CODE_INT, 1, 0,
"<variable (not text or data), no debug info>",
NULL);
+
+ msym_text_tls_symbol_type =
+ init_type (TYPE_CODE_FUNC, 1, 0, "<TLS-based text variable, no debug info>", NULL);
+ TYPE_TARGET_TYPE (msym_text_tls_symbol_type) = builtin_type_int;
+ msym_data_tls_symbol_type =
+ init_type (TYPE_CODE_INT, TARGET_INT_BIT / HOST_CHAR_BIT, 0,
+ "<TLS-based data variable, no debug info>", NULL);
+ msym_unknown_tls_symbol_type =
+ init_type (TYPE_CODE_INT, 1, 0,
+ "<TLS-based variable (not text or data), no debug info>",
+ NULL);
}

/* This function avoids direct calls to fprintf
Index: parser-defs.h
===================================================================
RCS file: /cvs/src/src/gdb/parser-defs.h,v
retrieving revision 1.20
diff -u -p -r1.20 parser-defs.h
--- parser-defs.h 17 Dec 2005 22:34:01 -0000 1.20
+++ parser-defs.h 25 Aug 2006 19:55:41 -0000
@@ -131,6 +131,8 @@ extern void write_exp_bitstring (struct

extern void write_exp_elt_block (struct block *);

+extern void write_exp_elt_objfile (struct objfile *objfile);
+
extern void write_exp_msymbol (struct minimal_symbol *,
struct type *, struct type *);

Index: target.c
===================================================================
RCS file: /cvs/src/src/gdb/target.c,v
retrieving revision 1.124
diff -u -p -r1.124 target.c
--- target.c 16 Aug 2006 18:31:03 -0000 1.124
+++ target.c 25 Aug 2006 19:55:43 -0000
@@ -39,6 +39,7 @@
#include "regcache.h"
#include "gdb_assert.h"
#include "gdbcore.h"
+#include "exceptions.h"

static void target_info (char *, int);

@@ -755,6 +756,103 @@ pop_target (void)
internal_error (__FILE__, __LINE__, _("failed internal consistency check"));
}

+/* Using the objfile specified in BATON, find the address for the
+ current thread's thread-local storage with offset OFFSET. */
+CORE_ADDR
+target_translate_tls_address (struct objfile *objfile, CORE_ADDR offset)
+{
+ volatile CORE_ADDR addr = 0;
+
+ if (target_get_thread_local_address_p ()
+ && gdbarch_fetch_tls_load_module_address_p (current_gdbarch))
+ {
+ ptid_t ptid = inferior_ptid;
+ volatile struct gdb_exception ex;
+
+ TRY_CATCH (ex, RETURN_MASK_ALL)
+ {
+ CORE_ADDR lm_addr;
+
+ /* Fetch the load module address for this objfile. */
+ lm_addr = gdbarch_fetch_tls_load_module_address (current_gdbarch,
+ objfile);
+ /* If it's 0, throw the appropriate exception. */
+ if (lm_addr == 0)
+ throw_error (TLS_LOAD_MODULE_NOT_FOUND_ERROR,
+ _("TLS load module not found"));
+
+ addr = target_get_thread_local_address (ptid, lm_addr, offset);
+ }
+ /* If an error occurred, print TLS related messages here. Otherwise,
+ throw the error to some higher catcher. */
+ if (ex.reason < 0)
+ {
+ int objfile_is_library = (objfile->flags & OBJF_SHARED);
+
+ switch (ex.error)
+ {
+ case TLS_NO_LIBRARY_SUPPORT_ERROR:
+ error (_("Cannot find thread-local variables in this thread library."));
+ break;
+ case TLS_LOAD_MODULE_NOT_FOUND_ERROR:
+ if (objfile_is_library)
+ error (_("Cannot find shared library `%s' in dynamic"
+ " linker's load module list"), objfile->name);
+ else
+ error (_("Cannot find executable file `%s' in dynamic"
+ " linker's load module list"), objfile->name);
+ break;
+ case TLS_NOT_ALLOCATED_YET_ERROR:
+ if (objfile_is_library)
+ error (_("The inferior has not yet allocated storage for"
+ " thread-local variables in\n"
+ "the shared library `%s'\n"
+ "for %s"),
+ objfile->name, target_pid_to_str (ptid));
+ else
+ error (_("The inferior has not yet allocated storage for"
+ " thread-local variables in\n"
+ "the executable `%s'\n"
+ "for %s"),
+ objfile->name, target_pid_to_str (ptid));
+ break;
+ case TLS_GENERIC_ERROR:
+ if (objfile_is_library)
+ error (_("Cannot find thread-local storage for %s, "
+ "shared library %s:\n%s"),
+ target_pid_to_str (ptid),
+ objfile->name, ex.message);
+ else
+ error (_("Cannot find thread-local storage for %s, "
+ "executable file %s:\n%s"),
+ target_pid_to_str (ptid),
+ objfile->name, ex.message);
+ break;
+ default:
+ throw_exception (ex);
+ break;
+ }
+ }
+ }
+ /* It wouldn't be wrong here to try a gdbarch method, too; finding
+ TLS is an ABI-specific thing. But we don't do that yet. */
+ else
+ {
+ struct minimal_symbol *msymbol;
+
+ msymbol = lookup_minimal_symbol ("errno", NULL, NULL);
+ if (msymbol != NULL
+ && SYMBOL_VALUE_ADDRESS (msymbol) == offset
+ && SYMBOL_BFD_SECTION (msymbol)->owner == objfile->obfd)
+ error (_("TLS symbol `errno' not resolved for non-TLS program."
+ " You should use symbol \"(*__errno_location ())\" or"
+ " compile the program with `gcc -ggdb3' or `gcc -pthread'."));
+ error (_("Cannot find thread-local variables on this target"));
+ }
+
+ return addr;
+}
+
#undef MIN
#define MIN(A, B) (((A) <= (B)) ? (A) : (B))

Index: target.h
===================================================================
RCS file: /cvs/src/src/gdb/target.h,v
retrieving revision 1.87
diff -u -p -r1.87 target.h
--- target.h 15 Aug 2006 18:46:25 -0000 1.87
+++ target.h 25 Aug 2006 19:55:44 -0000
@@ -1131,6 +1131,9 @@ extern void target_preopen (int);

extern void pop_target (void);

+extern CORE_ADDR target_translate_tls_address (struct objfile *objfile,
+ CORE_ADDR offset);
+
/* Struct section_table maps address ranges to file sections. It is
mostly used with BFD files, but can be used without (e.g. for handling
raw disks, or files not in formats handled by BFD). */
Index: valops.c
===================================================================
RCS file: /cvs/src/src/gdb/valops.c,v
retrieving revision 1.164
diff -u -p -r1.164 valops.c
--- valops.c 13 Jul 2006 04:31:42 -0000 1.164
+++ valops.c 25 Aug 2006 19:55:46 -0000
@@ -501,7 +501,8 @@ value_at (struct type *type, CORE_ADDR a
/* Return a lazy value with type TYPE located at ADDR (cf. value_at). */

struct value *
-value_at_lazy (struct type *type, CORE_ADDR addr)
+value_at_lazy_tls (struct type *type, CORE_ADDR addr,
+ struct objfile *tls_objfile)
{
struct value *val;

@@ -512,11 +513,19 @@ value_at_lazy (struct type *type, CORE_A

VALUE_LVAL (val) = lval_memory;
VALUE_ADDRESS (val) = addr;
+ if (tls_objfile != NULL)
+ set_value_tls_objfile (val, tls_objfile);
set_value_lazy (val, 1);

return val;
}

+struct value *
+value_at_lazy (struct type *type, CORE_ADDR addr)
+{
+ return value_at_lazy_tls (type, addr, NULL);
+}
+
/* Called only from the value_contents and value_contents_all()
macros, if the current data for a variable needs to be loaded into
value_contents(VAL). Fetches the data from the user's process, and
@@ -538,7 +547,17 @@ value_fetch_lazy (struct value *val)

struct type *type = value_type (val);
if (length)
- read_memory (addr, value_contents_all_raw (val), length);
+ {
+ struct objfile *tls_objfile = value_tls_objfile (val);
+
+ if (tls_objfile != NULL)
+ {
+ /* `target_translate_tls_address' uses `inferior_ptid'. */
+ addr = target_translate_tls_address (tls_objfile, addr);
+ }
+
+ read_memory (addr, value_contents_all_raw (val), length);
+ }

set_value_lazy (val, 0);
return 0;
@@ -596,6 +615,7 @@ value_assign (struct value *toval, struc
CORE_ADDR changed_addr;
int changed_len;
gdb_byte buffer[sizeof (LONGEST)];
+ struct objfile *tls_objfile = value_tls_objfile (toval);

if (value_bitsize (toval))
{
@@ -624,6 +644,13 @@ value_assign (struct value *toval, struc
dest_buffer = value_contents (fromval);
}

+ if (tls_objfile != NULL)
+ {
+ /* `target_translate_tls_address' uses `inferior_ptid'. */
+ changed_addr = target_translate_tls_address (tls_objfile,
+ changed_addr);
+ }
+
write_memory (changed_addr, dest_buffer, changed_len);
if (deprecated_memory_changed_hook)
deprecated_memory_changed_hook (changed_addr, changed_len);
Index: value.c
===================================================================
RCS file: /cvs/src/src/gdb/value.c,v
retrieving revision 1.36
diff -u -p -r1.36 value.c
--- value.c 31 Mar 2006 10:36:18 -0000 1.36
+++ value.c 25 Aug 2006 19:55:47 -0000
@@ -158,6 +158,9 @@ struct value
actually exist in the program. */
char optimized_out;

+ /* TLS owner. */
+ struct objfile *tls_objfile;
+
/* Actual contents of the value. For use of this value; setting it
uses the stuff above. Not valid if lazy is nonzero. Target
byte-order. We force it to be aligned properly for any possible
@@ -230,6 +233,7 @@ allocate_value (struct type *type)
VALUE_REGNUM (val) = -1;
val->lazy = 0;
val->optimized_out = 0;
+ val->tls_objfile = NULL;
val->embedded_offset = 0;
val->pointed_to_offset = 0;
val->modifiable = 1;
@@ -344,6 +348,18 @@ set_value_lazy (struct value *value, int
value->lazy = val;
}

+struct objfile *
+value_tls_objfile (struct value *value)
+{
+ return value->tls_objfile;
+}
+
+void
+set_value_tls_objfile (struct value *value, struct objfile *tls_objfile)
+{
+ value->tls_objfile = tls_objfile;
+}
+
const gdb_byte *
value_contents (struct value *value)
{
Index: value.h
===================================================================
RCS file: /cvs/src/src/gdb/value.h,v
retrieving revision 1.92
diff -u -p -r1.92 value.h
--- value.h 13 Jul 2006 04:31:42 -0000 1.92
+++ value.h 25 Aug 2006 19:55:48 -0000
@@ -154,6 +154,10 @@ extern void set_value_embedded_offset (s
extern int value_lazy (struct value *);
extern void set_value_lazy (struct value *value, int val);

+extern struct objfile *value_tls_objfile (struct value *value);
+extern void set_value_tls_objfile (struct value *value,
+ struct objfile *tls_objfile);
+
/* value_contents() and value_contents_raw() both return the address
of the gdb buffer used to hold a copy of the contents of the lval.
value_contents() is used when the contents of the buffer are needed
@@ -277,6 +281,8 @@ extern struct value *value_from_double (
extern struct value *value_from_string (char *string);

extern struct value *value_at (struct type *type, CORE_ADDR addr);
+extern struct value *value_at_lazy_tls (struct type *type, CORE_ADDR addr,
+ struct objfile *tls_objfile);
extern struct value *value_at_lazy (struct type *type, CORE_ADDR addr);

extern struct value *value_from_register (struct type *type, int regnum,
Index: testsuite/gdb.threads/tls-nodebug.c
===================================================================
RCS file: testsuite/gdb.threads/tls-nodebug.c
diff -N testsuite/gdb.threads/tls-nodebug.c
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ testsuite/gdb.threads/tls-nodebug.c 25 Aug 2006 19:55:48 -0000
@@ -0,0 +1,8 @@
+/* Test accessing TLS based variable without any debug info compiled. */
+
+__thread int thread_local = 42;
+
+int main(void)
+{
+ return 0;
+}
Index: testsuite/gdb.threads/tls-nodebug.exp
===================================================================
RCS file: testsuite/gdb.threads/tls-nodebug.exp
diff -N testsuite/gdb.threads/tls-nodebug.exp
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ testsuite/gdb.threads/tls-nodebug.exp 25 Aug 2006 19:55:49 -0000
@@ -0,0 +1,52 @@
+# tls.exp -- Expect script to test thread-local storage without debuginfo
+# Copyright (C) 2006 Free Software Foundation, Inc.
+
+# 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 2 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, write to the Free Software
+# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
+
+# Please email any bugs, comments, and/or additions to this file to:
+# bug-gdb@prep.ai.mit.edu
+
+set testfile tls-nodebug
+set srcfile ${testfile}.c
+set binfile ${objdir}/${subdir}/${testfile}
+
+if [istarget "*-*-linux"] then {
+ set target_cflags "-D_MIT_POSIX_THREADS"
+} else {
+ set target_cflags ""
+}
+
+if {[gdb_compile_pthreads "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable $options] != "" } {
+ return -1
+}
+
+gdb_exit
+gdb_start
+gdb_reinitialize_dir $srcdir/$subdir
+
+gdb_load ${binfile}
+if ![runto_main] then {
+ fail "Can't run to main"
+ return 0
+}
+
+# Formerly: Cannot access memory at address 0x0
+gdb_test "p thread_local" "= 42" "thread local storage"
+
+# Done!
+#
+gdb_exit
+
+return 0