This patch moves most of the demangling logic out of
symbol_find_demangled_name into the various language_defn objects.
The simplest way to do this seemed to be to add a new method to
language_defn. This is shame given the existing la_demangle, but
given Ada's unusual needs, and the differing demangling options
between languages, la_demangle didn't seem to fit.
In order to make this work, I made enum language order-sensitive.
This helps preserve the current ordering of demangling operations.
2016-06-23 Tom Tromey <tom@tromey.com>
* symtab.c (symbol_find_demangled_name): Loop over languages and
use language_sniff_from_mangled_name.
* rust-lang.c (rust_sniff_from_mangled_name): New function.
(rust_language_defn): Update.
* p-lang.c (pascal_language_defn): Update.
* opencl-lang.c (opencl_language_defn): Update.
* objc-lang.c (objc_sniff_from_mangled_name): New function.
(objc_language_defn): Update.
* m2-lang.c (m2_language_defn): Update.
* language.h (struct language_defn) <la_sniff_from_mangled_name>: New
field.
(language_sniff_from_mangled_name): Declare.
* language.c (language_sniff_from_mangled_name): New function.
(unknown_language_defn, auto_language_defn, local_language_defn):
Update.
* jv-lang.c (java_sniff_from_mangled_name): New function.
(java_language_defn): Use it.
* go-lang.c (go_sniff_from_mangled_name): New function.
(go_language_defn): Use it.
* f-lang.c (f_language_defn): Update.
* defs.h (enum language): Reorder.
* d-lang.c (d_sniff_from_mangled_name): New function.
(d_language_defn): Use it.
* cp-support.h (gdb_sniff_from_mangled_name): Declare.
* cp-support.c (gdb_sniff_from_mangled_name): New function.
* c-lang.c (c_language_defn, cplus_language_defn)
(asm_language_defn, minimal_language_defn): Update.
* ada-lang.c (ada_sniff_from_mangled_name): New function.
(ada_language_defn): Use it.
This moves filename extensions from a function in symfile.c out to
each language_defn. I think this is an improvement because it means
less digging around when writing a new language port.
2016-06-23 Tom Tromey <tom@tromey.com>
* ada-lang.c (ada_extensions): New array.
(ada_language_defn): Use it.
* c-lang.c (c_extensions): New array.
(c_language_defn): Use it.
(cplus_extensions): New array.
(cplus_language_defn): Use it.
(asm_extensions): New array.
(asm_language_defn): Use it.
(minimal_language_defn): Update.
* d-lang.c (d_extensions): New array.
(d_language_defn): Use it.
* f-lang.c (f_extensions): New array.
(f_language_defn): Use it.
* go-lang.c (go_language_defn): Update.
* jv-lang.c (java_extensions): New array.
(java_language_defn): Use it.
* language.c (add_language): Call add_filename_language.
(unknown_language_defn, auto_language_defn, local_language_defn):
Update.
* language.h (struct language_defn) <la_filename_extensions>: New
field.
* m2-lang.c (m2_language_defn): Update.
* objc-lang.c (objc_extensions): New array.
(objc_language_defn): Use it.
* opencl-lang.c (opencl_language_defn): Update.
* p-lang.c (p_extensions): New array.
(pascal_language_defn): Use it.
* rust-lang.c (rust_extensions): New array.
(rust_language_defn): Use it.
* symfile.c (add_filename_language): No longer static. Make "ext"
const.
(init_filename_language_table): Remove.
(_initialize_symfile): Update.
* symfile.h (add_filename_language): Declare.
Looking at testsuite results, I noticed this warning in an MI test:
~"\nCatchpoint "
~"2, "
&"warning: failed to get exception name: No definition of \"e.full_name\" in current context.\n"
~"exception at 0x000000000040192d in foo () at /home/pedro/brno/pedro/gdb/mygit/src/gdb/testsuite/gdb.ada/mi_catch_ex/foo.adb:20\n"
~"20\t raise Constraint_Error; -- SPOT1\n"
*stopped,reason="breakpoint-hit",disp="keep",bkptno="2",exception-name="CONSTRAINT_ERROR",frame={addr="0x000000000040192d",func="foo",args=[],file="/home/pedro/brno/pedro/gdb/mygit/src/gdb/testsuite/gdb.ada/mi_catch_ex/foo.adb",fullname="/home/pedro/brno/pedro/gdb/mygit/src/gdb/testsuite/gdb.ada/mi_catch_ex/foo.adb",line="20"},thread-id="1",stopped-threads="all",core="5"
(gdb)
PASS: gdb.ada/mi_catch_ex.exp: continue until CE caught by all-exceptions catchpoint
The problem is that:
- MI prints the breakpoint hit twice: once on the MI stream;
another time on the console stream.
- After printing the Ada catchpoint hit, gdb selects a non-current
frame, from within the catchpoint's print_it routine.
So the second time the breakpoint is printed, the selected frame is no
longer the current frame, and then evaluating e.full_name in
ada_exception_name_addr fails.
This commit fixes the problem and enhances the gdb.ada/mi_catch_ex.exp
test to make sure the catchpoint hit is printed correctly on the
console stream too.
gdb/ChangeLog:
2016-06-21 Pedro Alves <palves@redhat.com>
* ada-lang.c (ada_exception_name_addr_1): Add comment.
(print_it_exception): Select the current frame.
gdb/testsuite/ChangeLog:
2016-06-21 Pedro Alves <palves@redhat.com>
* gdb.ada/mi_catch_ex.exp (continue_to_exception): New procedure.
(top level): Use it instead of mi_execute_to.
This factors out all the yy-variables remapping to a single file,
instead of each parser having to do the same, with different prefixes.
With this, a parser just needs to define the prefix they want and
include yy-remap.h, which does the dirty job.
Note this renames the c_error, ada_error, etc. functions. Writing the
remapping pattern as:
#define yyerror GDB_YY_REMAP (error)
instead of:
#define yyerror GDB_YY_REMAP (yyerror)
would have avoided the renaming. However, that would be problematic
if we have a macro 'foo' in scope, when we write:
#define yyfoo GDB_YY_REMAP (foo)
as that would expand 'foo'.
The c_yyerror etc. naming end ups indicating that this is a yacc
related function more clearly, so feels like a good change, anyway.
gdb/ChangeLog:
2016-04-22 Pedro Alves <palves@redhat.com>
* ada-exp.y: Remove all yy symbol remappings.
(GDB_YY_REMAP_PREFIX): Define.
Include "yy-remap.h".
* ada-lang.c (ada_language_defn): Adjust.
* ada-lang.h (ada_error): Rename to ...
(ada_yyerror): ... this.
* c-exp.y: Remove all yy symbol remappings.
(GDB_YY_REMAP_PREFIX): Define.
Include "yy-remap.h".
* c-lang.c (c_language_defn, cplus_language_defn)
(asm_language_defn, minimal_language_defn): Adjust.
* c-lang.h (c_error): Rename to ...
(c_yyerror): ... this.
* d-exp.y: Remove all yy symbol remappings.
(GDB_YY_REMAP_PREFIX): Define.
Include "yy-remap.h".
* d-lang.c (d_language_defn): Adjust.
* d-lang.h (d_error): Rename to ...
(d_yyerror): ... this.
* f-exp.y: Remove all yy symbol remappings.
(GDB_YY_REMAP_PREFIX): Define.
Include "yy-remap.h".
* f-lang.c (f_language_defn): Adjust.
* f-lang.h (f_error): Rename to ...
(f_yyerror): ... this.
* go-exp.y: Remove all yy symbol remappings.
(GDB_YY_REMAP_PREFIX): Define.
Include "yy-remap.h".
* go-lang.c (go_language_defn): Adjust.
* go-lang.h (go_error): Rename to ...
(go_yyerror): ... this.
* jv-exp.y: Remove all yy symbol remappings.
(GDB_YY_REMAP_PREFIX): Define.
Include "yy-remap.h".
* jv-lang.c (java_language_defn): Adjust.
* jv-lang.h (java_error): Rename to ...
(java_yyerror): ... this.
* m2-exp.y: Remove all yy symbol remappings.
(GDB_YY_REMAP_PREFIX): Define.
Include "yy-remap.h".
* m2-lang.c (m2_language_defn): Adjust.
* m2-lang.h (m2_error): Rename to ...
(m2_yyerror): ... this.
* objc-exp.y: Remove all yy symbol remappings.
(GDB_YY_REMAP_PREFIX): Define.
Include "yy-remap.h".
* objc-lang.c (objc_language_defn): Adjust.
* opencl-lang.c (opencl_language_defn): Adjust.
* p-exp.y: Remove all yy symbol remappings.
(GDB_YY_REMAP_PREFIX): Define.
Include "yy-remap.h".
* p-lang.c (pascal_language_defn): Adjust.
* p-lang.h (pascal_error): Rename to ...
(pascal_yyerror): ... this.
* yy-remap.h: New file.
Compiling gdb with --enable-build-with-cxx --disable-nls, we get:
.../src/gdb/ada-lang.c:7657:16: error: invalid conversion from ‘const char*’ to ‘char*’ [-fpermissive]
type_str = (type != NULL
^
In file included from .../src/gdb/common/common-defs.h:67:0,
from .../src/gdb/defs.h:28,
from .../src/gdb/ada-lang.c:21:
.../src/gdb/common/gdb_locale.h:40:27: error: invalid conversion from ‘const char*’ to ‘char*’ [-fpermissive]
# define _(String) (String)
^
.../src/gdb/ada-lang.c:7730:46: note: in expansion of macro ‘_’
char *name_str = name != NULL ? name : _("<null>");
^
Makefile:1140: recipe for target 'ada-lang.o' failed
gdb/ChangeLog:
2016-04-15 Pedro Alves <palves@redhat.com>
* ada-lang.c (ada_lookup_struct_elt_type): Constify 'type_str' and
'name_str' locals.
A couple wrong things here
- We should not use target_terminal_ours when all we want is output.
We should use target_terminal_ours_for_output instead, which
preserves raw/cooked terminal modes, and SIGINT forwarding.
- Most importantly, relying on stderr output immediately preceding
the error/exception print isn't correct. The exception could be
caught and handled, for example; MI frontends won't display the
stderr part in an error dialog box. Etc.
This commit introduces a type_as_string helper that allows building a
full error string including type info.
gdb/ChangeLog:
2016-04-12 Pedro Alves <palves@redhat.com>
* ada-lang.c (type_as_string, type_as_string_and_cleanup): New
functions.
(ada_lookup_struct_elt_type): Use type_as_string_and_cleanup.
GCC6 will warn about misleading indentation issues like:
gdb/ada-lang.c: In function ‘ada_evaluate_subexp’:
ada-lang.c:11423:9: error: statement is indented as if it were guarded by...
arg1 = unwrap_value (arg1);
^~~~
gdb/ada-lang.c:11421:7: note: ...this ‘else’ clause, but it is not
else
^~~~
In this case it would be a bug except for the fact the if clause already
returned early. So this misindented statement really only got executed
for the else case. But it could easily mislead a reader, so adding a
proper else block is the correct solution.
In case of c-typeprint.c (c_type_print_base) the if statement is indeed
misleadingly indented, but not a bug. Just indent correctly. The inflow.c
(terminal_ours_1) misindented block comes from the removal of an if clause
in commit d9d2d8b which looks correct. Just introduce an else to fixup the
indentation of the block. The linux-record.c misleadingly indented return
statements are just that. Misleading to the reader, but not actual bugs.
Just unindent them so they don't look like they fall under the wrong if
clause.
So far, trying to evaluate an expression involving a function call for
which GDB could find multiple function candidates outputs a menu so that
the user can select the one to run. For instance, with the two
following functions:
type New_Integer is new Integer;
function F (I : Integer) return Boolean;
function F (I : New_Integer) return Boolean;
Then we get the following GDB session:
(gdb) print f(1)
Multiple matches for f
[0] cancel
[1] foo.f at foo.adb:23
[2] foo.f at foo.adb.28
>
While the source location information is sufficient in order to
determine which one to select, one has to look for them in source files,
which is not convenient.
This commit tunes this menu in order to also include the list of formal
and return types (if any) in each entry. The above then becomes:
(gdb) print f(1)
Multiple matches for f
[0] cancel
[1] foo.f (integer) return boolean at foo.adb:23
[2] foo.f (foo.new_integer) return boolean at foo.adb.28
>
Since this output is more verbose than previously, this change also
introduces an option (set/show ada print-signatures) to get the original
output.
gdb/ChangeLog:
* ada-lang.c (print_signatures): New.
(ada_print_symbol_signature): New.
(user_select_syms): Add signatures to the output of candidate
symbols using ada_print_symbol_signature.
(_initialize_ada_language): Add a "set/show ada
print-signatures" boolean option.
gdb/testsuite/ChangeLog:
* gdb.ada/fun_overload_menu.exp: New testcase.
* gdb.ada/fun_overload_menu/foo.adb: New testcase.
Tested on x86_64-linux, no regression.
Consider a function with the following signature...
function F (R : out Rec_Type) return Enum_Type;
... where Rec_Type is a simple record:
type Rec_Type is record
Cur : Integer;
end record;
Trying to "finish" from that function causes GDB to SEGV:
(gdb) fin
Run till exit from #0 bar.f (r=...) at bar.adb:5
0x00000000004022fe in foo () at foo.adb:5
5 I : Enum_Type := F (R);
[1] 18949 segmentation fault (core dumped) /[..]/gdb
This is related to the fact that funtion F has a parameter (R)
which is an "out" parameter being passed by copy. For those,
GNAT transforms the return value to be a record with multiple
fields: The first one is called "RETVAL" and contains the return
value shown in the source, and the remaining fields have the same
name as the "out" or "in out" parameters which are passed by copy.
So, in the example above, function F returns a struct that has
one field who name is "r".
Because "RETVAL" starts with "R", GDB thinks it's a wrapper field,
because it looks like the encoding used for variant records:
-- member_name ::= {choice} | others_choice
-- choice ::= simple_choice | range_choice
-- simple_choice ::= S number
-- range_choice ::= R number T number <<<<<----- here
-- number ::= {decimal_digit} [m]
-- others_choice ::= O (upper case letter O)
See ada_is_wrapper_field:
return (name != NULL
&& (startswith (name, "PARENT")
|| strcmp (name, "REP") == 0
|| startswith (name, "_parent")
|| name[0] == 'S' || name[0] == 'R' || name[0] == 'O'));
As a result of this, when trying to print the RETURN value,
we think that RETVAL is a wrapper, and thus recurse into
print_field_values...
if (ada_is_wrapper_field (type, i))
{
comma_needed =
print_field_values (TYPE_FIELD_TYPE (type, i),
valaddr,
(offset
+ TYPE_FIELD_BITPOS (type, i) / HOST_CHAR_BIT),
stream, recurse, val, options,
comma_needed, type, offset, language);
... which is a problem since print_field_values assumes that
the type it is given ("TYPE_FIELD_TYPE (type, i)" here), is also
a record type. However, that's not the case, since RETVAL is
an enum. That eventually leads GDB to a NULL type when trying to
extract fields out of the enum, which then leads to a SEGV when
trying to dereference it.
Ideally, we'd want to be a little more careful in identifying
wrapper fields, by enhancing ada_is_wrapper_field to be a little
more complete in its analysis of the field name before declaring
it a variant record wrapper. However, it's not super easy to do
so, considering that the choices can be combined together when
complex choices are used. Eg:
-- [...] the choice 1 .. 4 | 7 | -10 would be represented by
-- R1T4S7S10m
Given that we are working towards getting rid of GNAT encodings,
which means that the above will eventually disappear, we took
the more pragmatic approach is just treating RETVAL as a special
case.
gdb/ChangeLog:
* ada-lang.c (ada_is_wrapper_field): Add special handling
for fields called "RETVAL".
gdb/testsuite/ChangeLog:
* gdb.ada/fin_fun_out: New testcase.
This adds a guard that the size of the "unpacked" buffer is large enough
to contain at least BIT_SIZE bits. If not, report an error. This is to
guard this routine from doing buffer overflows when called incorrectly.
gdb/ChangeLog:
* ada-lang.c (ada_unpack_from_contents): Add guard that unpacked
is large enough for BIT_SIZE. Update function comment.
This patch fixes a buffer overflow in ada_unpack_from_contents
caused by one of the previous commits. This happens when trying
to print the value of an array of variant records.
The overflow happens while trying to print one element of the array.
Because the size of each element in the array is variable, the array
has a DWARF byte_stride attribute, which makes us treat the array
as if it was packed. And during the extraction of each array element,
we try to unpack an object using the array's byte stride as the size,
into an element whose size is actually less than the stride.
This patch fixes the issue by overriding the byte-stride with
the actual element's length.
gdb/ChangeLog:
* ada-lang.c (ada_value_primitive_packed_val): Move
src_len variable to local block where used. Override
BIT_SIZE if bigger than size of resolved type.
Just a small cleanup, to avoid code duplication...
gdb/ChangeLog:
* gdbtypes.h (is_scalar_type): Add extern declaration.
* gdbtypes.c (is_scalar_type): Make non-static.
* ada-lang.c (ada_value_primitive_packed_val): Use is_scalar_type
to compute IS_SCALAR instead of doing it ourselves.
There is some partial handling for dynamic types in
ada_value_primitive_packed_val, but this support was added
in a fairly ad hoc way, and actually only covered the situation
where OBJ is not NULL and its contents had not been fetched yet.
In addition, even in the cases that it does cover, it doesn't make
much sense. In particular, it was adjusting BIT_SIZE and SRC_LEN,
which are properties of the data to be extracted _from_, based
on TYPE's length once resolved, which is a property of the data
we want to extract _to_.
This patch hopefully adjust this function to handle dynamic types
correctly, and in all cases. It does so by unpacking the data into
a temporary buffer in order to use that buffer to resolve the type.
And _then_ creates the resulting value from that resolved type.
gdb/ChangeLog:
* ada-lang.c (ada_value_primitive_packed_val): Rework handling
of case where TYPE is dynamic.
This patch is just preparation work which splits the function
ada_value_primitive_packed_val into two function: one which unpacks
the data, and the other which now uses it to implement
ada_value_primitive_packed_val.
This simplifies a bit ada_value_primitive_packed_val, but will also
allow us to use the new function to unpack data without actually creating
a struct value as a result.
gdb/ChangeLog:
* ada-lang.c (ada_unpack_from_contents): New function,
extracted from ada_value_primitive_packed_val.
(ada_value_primitive_packed_val): Replace extracted out code
by call to ada_unpack_from_contents.
This patch just changes the order in which local variables are declared
so as to group the logically-related variables together. No code
change otherwise.
gdb/ChangeLog:
* ada-lang.c (ada_value_primitive_packed_val): Reorder local
variable declarations.
... instead of "unsigned char".
gdb/Changelog:
* ada-lang.c (ada_value_primitive_packed_val): Change the type
of local variables src and unpacked to "gdb_type *" instead of
"unsigned char *".
A number of local variables declared in ada_value_primitive_packed_val
have a name that could, IMO, be improved to, either: Be more explicit
about what the variable is about (Eg: "src" is an index, so rename it
to "src_idx"); or be more consistent with other variables that they
relate to: for instance, several variables refer to the source via
"src" (Eg: srcBitsLeft, nsrc), but the buffer they refer to is called
"bytes", so patch renames "bytes" to "src".
This should help read and understand a little more easily the code
inside this function. No real code change otherwise.
gdb/ChangeLog:
* ada-lang.c (ada_value_primitive_packed_val): Make the name
of various local variables more explicit and consistent.
No real code change otherwise.
Compilers can materialize renamings of arrays (or of accesses to arrays)
in Ada into variables whose types are references to the actual array
types. Before this change, trying to use such an array renaming yielded
an error in GDB:
(gdb) print my_array(1)
cannot subscript or call a record
(gdb) print my_array_ptr(1)
cannot subscript or call something of type `(null)'
This behavior comes from bad handling for array renamings, in particular
the OP_FUNCALL expression operator handling from ada-lang.c
(ada_evaluate_subexp): in one place we turn the reference into a
pointer, but the code that follows expect the value to be an array.
This patch fixes how we handle references in call/subscript evaluation
so that we turn these references into the actual array values instead of
pointers to them.
gdb/ChangeLog:
* ada-lang.c (ada_evaluate_subexp) <OP_FUNCALL>: When the input
value is a reference, actually dereference it in order to get
the underlying value.
gdb/testsuite/ChangeLog:
* gdb.ada/array_ptr_renaming.exp: New testcase.
* gdb.ada/array_ptr_renaming/foo.adb: New file.
* gdb.ada/array_ptr_renaming/pack.ads: New file.
Tested on x86_64-linux, no regression.
This change is relevant only for standard DWARF (as opposed to the GNAT
encodings extensions): at the time of writing it only makes a difference
with GCC patches that are to be integrated: see in particular
<https://gcc.gnu.org/ml/gcc-patches/2015-07/msg01364.html>.
Given the following Ada declarations:
type Small is mod 2 ** 6;
type Array_Type is array (0 .. 9) of Small
with Pack;
type Array_Access is access all Array_Type;
A : aliased Array_Type := (1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
AA : constant Array_Type := A'Access;
Before this change, we would get the following GDB session:
(gdb) print aa.all(2)
$1 = 3
(gdb) print aa(2)
$2 = 16
This is wrong: both expression should yield the same value: 3. The
problem is simply that the routine which handles accesses to arrays lack
general handling for packed arrays. After this patch, we have the
expected output:
(gdb) print aa.all(2)
$1 = 3
(gdb) print aa(2)
$2 = 3
gdb/ChangeLog:
* ada-lang.c (ada_value_ptr_subscript): Update the heading
comment. Handle packed arrays.
gdb/testsuite/ChangeLog:
* gdb.ada/access_to_packed_array.exp: New testcase.
* gdb.ada/access_to_packed_array/foo.adb: New file.
* gdb.ada/access_to_packed_array/pack.adb: New file.
* gdb.ada/access_to_packed_array/pack.ads: New file.
Tested on x86_64-linux, no regression.
I found this const/not const mixup found by building in C++ mode.
gdb/ChangeLog:
* ada-lang.c (ada_search_struct_field): Constify parameters
and/or variables..
(xget_renaming_scope): Likewise.
(ada_is_redundant_range_encoding): Likewise.
(scan_discrim_bound): Likewise.
(to_fixed_range_type): Likewise.
Before this change, trying to call an overloaded function with at least
one character literal in argument would fail. For instance, given these
two functions:
function F (C : Character) return Integer is
begin
return Character'Pos (C);
end F;
function F (I : Integer) return Integer is
begin
return -I;
end F;
We would get the following GDB session:
(gdb) p f('A')
$1 = -65
(gdb) p f(1)
$1 = -1
This is wrong because the first call should select the first F function
and thus return 65.
The root problem is that ada-lang.c:ada_language_arch_info stores in
string_char_type a type whose code is TYPE_CODE_INT instead of
TYPE_CODE_CHAR. As a result, all parsed character literals are turned
into integer values and during overload matching, the TYPE_CODE_CHAR
formal rejects the TYPE_CODE_INT actual.
This change turns string_char_type into a true TYPE_CODE_CHAR type in
ada-lang.c so that we have instead the expected:
(gdb) p f('A')
$1 = 65
gdb/ChangeLog:
* ada-lang.c (ada_language_arch_info): Create a TYPE_CODE_CHAR
type instead of a TYPE_CODE_INT one for the string_char_type
and the ada_primitive_type_char types.
gdb/testsuite/ChangeLog:
* gdb.ada/funcall_char.exp: New testcase.
* gdb.ada/funcall_char/foo.adb: New file.
Tested on x86_64-linux, no regression.
Before this change, trying to complete an expression ending with an
ambiguous function name (i.e. for which there are multiple matches)
would display a menu with a prompt for the user to pick one. For
instance:
(gdb) p func<tab>Multiple matches for func
[0] cancel
[1] pack2.func at pack2.adb:5
[2] pack.func at pack.adb:5
>
This is not user friendly and actually triggered a segmentation fault
after the user did pick one. It is not clear whether the segmentation
fault needs a separate fix, but this is the only known case which
exhibits it at the moment, and this case must be fixed itself.
The problem lies in ada-lang.c (ada_resolve_function): when we got
multiple matches, we should not display the menu if we are in completion
mode. This patch adjusts the corresponding condition accordingly.
gdb/ChangeLog:
* ada-lang.c (ada_resolve_function): Do not ask the user what
match to use when in completion mode.
gdb/testsuite/ChangeLog:
* gdb.ada/complete.exp: Add "pck.ambiguous_func" to the relevant
expected outputs. Add two testcases for completing ambiguous
functions.
* gdb.ada/complete/aux_pck.adb: New file.
* gdb.ada/complete/aux_pck.ads: New file.
* gdb.ada/complete/foo.adb: Pull Aux_Pck and call the two
Ambiguous_Func functions.
* gdb.ada/complete/pck.ads: Add an Ambiguous_Func function.
* gdb.ada/complete/pck.adb: Likewise.
Tested on x86_64-linux, no regression.
GDB's current behavior when dealing with non-local references in the
context of nested fuctions is approximative:
- code using valops.c:value_of_variable read the first available stack
frame that holds the corresponding variable (whereas there can be
multiple candidates for this);
- code directly relying on read_var_value will instead read non-local
variables in frames where they are not even defined.
This change adds the necessary context to symbol reads (to get the block
they belong to) and to blocks (the static link property, if any) so that
GDB can make the proper decisions when dealing with non-local varibale
references.
gdb/ChangeLog:
* ada-lang.c (ada_read_var_value): Add a var_block argument
and pass it to default_read_var_value.
* block.c (block_static_link): New accessor.
* block.h (block_static_link): Declare it.
* buildsym.c (finish_block_internal): Add a static_link
argument. If there is a static link, associate it to the new
block.
(finish_block): Add a static link argument and pass it to
finish_block_internal.
(end_symtab_get_static_block): Update calls to finish_block and
to finish_block_internal.
(end_symtab_with_blockvector): Update call to
finish_block_internal.
* buildsym.h: Forward-declare struct dynamic_prop.
(struct context_stack): Add a static_link field.
(finish_block): Add a static link argument.
* c-exp.y: Remove an obsolete comment (evaluation of variables
already start from the selected frame, and now they climb *up*
the call stack) and propagate the block information to the
produced expression.
* d-exp.y: Likewise.
* f-exp.y: Likewise.
* go-exp.y: Likewise.
* jv-exp.y: Likewise.
* m2-exp.y: Likewise.
* p-exp.y: Likewise.
* coffread.c (coff_symtab_read): Update calls to finish_block.
* dbxread.c (process_one_symbol): Likewise.
* xcoffread.c (read_xcoff_symtab): Likewise.
* compile/compile-c-symbols.c (convert_one_symbol): Promote the
"sym" parameter to struct block_symbol, update its uses and pass
its block to calls to read_var_value.
(convert_symbol_sym): Update the calls to convert_one_symbol.
* compile/compile-loc2c.c (do_compile_dwarf_expr_to_c): Update
call to read_var_value.
* dwarf2loc.c (block_op_get_frame_base): New.
(dwarf2_block_frame_base_locexpr_funcs): Implement the
get_frame_base method.
(dwarf2_block_frame_base_loclist_funcs): Likewise.
(dwarf2locexpr_baton_eval): Add a frame argument and use it
instead of the selected frame in order to evaluate the
expression.
(dwarf2_evaluate_property): Add a frame argument. Update call
to dwarf2_locexpr_baton_eval to provide a frame in available and
to handle the absence of address stack.
* dwarf2loc.h (dwarf2_evaluate_property): Add a frame argument.
* dwarf2read.c (attr_to_dynamic_prop): Add a forward
declaration.
(read_func_scope): Record any available static link description.
Update call to finish_block.
(read_lexical_block_scope): Update call to finish_block.
* findvar.c (follow_static_link): New.
(get_hosting_frame): New.
(default_read_var_value): Add a var_block argument. Use
get_hosting_frame to handle non-local references.
(read_var_value): Add a var_block argument and pass it to the
LA_READ_VAR_VALUE method.
* gdbtypes.c (resolve_dynamic_range): Update calls to
dwarf2_evaluate_property.
(resolve_dynamic_type_internal): Likewise.
* guile/scm-frame.c (gdbscm_frame_read_var): Update call to
read_var_value, passing it the block coming from symbol lookup.
* guile/scm-symbol.c (gdbscm_symbol_value): Update call to
read_var_value (TODO).
* infcmd.c (finish_command_continuation): Update call to
read_var_value, passing it the block coming from symbol lookup.
* infrun.c (insert_exception_resume_breakpoint): Likewise.
* language.h (struct language_defn): Add a var_block argument to
the LA_READ_VAR_VALUE method.
* objfiles.c (struct static_link_htab_entry): New.
(static_link_htab_entry_hash): New.
(static_link_htab_entry_eq): New.
(objfile_register_static_link): New.
(objfile_lookup_static_link): New.
(free_objfile): Free the STATIC_LINKS hashed map if needed.
* objfiles.h: Include hashtab.h.
(struct objfile): Add a static_links field.
(objfile_register_static_link): New.
(objfile_lookup_static_link): New.
* printcmd.c (print_variable_and_value): Update call to
read_var_value.
* python/py-finishbreakpoint.c (bpfinishpy_init): Likewise.
* python/py-frame.c (frapy_read_var): Update call to
read_var_value, passing it the block coming from symbol lookup.
* python/py-framefilter.c (extract_sym): Add a sym_block
parameter and set the pointed value to NULL (TODO).
(enumerate_args): Update call to extract_sym.
(enumerate_locals): Update calls to extract_sym and to
read_var_value.
* python/py-symbol.c (sympy_value): Update call to
read_var_value (TODO).
* stack.c (read_frame_local): Update call to read_var_value.
(read_frame_arg): Likewise.
(return_command): Likewise.
* symtab.h (struct symbol_block_ops): Add a get_frame_base
method.
(struct symbol): Add a block field.
(SYMBOL_BLOCK): New accessor.
* valops.c (value_of_variable): Remove frame/block handling and
pass the block argument to read_var_value, which does this job
now.
(value_struct_elt_for_reference): Update calls to
read_var_value.
(value_of_this): Pass the block found to read_var_value.
* value.h (read_var_value): Add a var_block argument.
(default_read_var_value): Likewise.
gdb/testsuite/ChangeLog:
* gdb.base/nested-subp1.exp: New file.
* gdb.base/nested-subp1.c: New file.
* gdb.base/nested-subp2.exp: New file.
* gdb.base/nested-subp2.c: New file.
* gdb.base/nested-subp3.exp: New file.
* gdb.base/nested-subp3.c: New file.
Consider the following declaration:
function Foo (I : Integer) return Integer renames Pack.Bar;
As Foo is not materialized as a routine whose name is derived from Foo,
GDB currently cannot use it:
(gdb) print foo(0)
No definition of "foo" in current context.
However, compilers can emit DW_TAG_imported_declaration in order to
materialize the fact that Foo is actually another name for Pack.Bar.
This commit enhances the DWARF reader to record global renamings (it
used to put global ones in a static block) and enhances the Ada engine
to leverage this information during symbol lookup.
gdb/ChangeLog:
* ada-lang.c: Include namespace.h
(aux_add_nonlocal_symbols): Fix a function name in comment.
(ada_add_block_renamings): New.
(add_nonlocal_symbols): Add global renamings handling.
(ada_lookup_symbol_list_worker): Move the symbol lookup part
to...
(ada_add_all_symbols): ... this new function.
(ada_add_block_symbols): Try to match the input name against the
"using directives list", perform a recursive symbol lookup on
the matched declarations.
* block.h (struct block): Move the_namespace to top-level as
namespace_info. Remove the language_specific field.
(BLOCK_NAMESPACE): Update access to the namespace_info field.
* buildsym.h (using_directives): Rename into...
(local_using_directives): ... this.
(global_using_directives): New.
(struct context_stack): Rename the using_directives field into
local_using_directives.
* buildsym.c (finish_block_internal): Deal with the proper
using directives repository (local or global).
(prepare_for_building): Reset local_using_directives. Assert
that there is no pending global using directive.
(reset_symtab_globals): Reset global_using_directives and
local_using_directives.
(end_symtab_get_static_block): Don't ignore symtabs that have
only using directives.
(push_context): Update references to local_using_directives.
(buildsym_init): Do not reset using_directives.
* cp-support.c: Include namespace.h.
* cp-support.h (struct using_direct): Move to namespace.h.
(cp_add_using_directives): Move to namespace.h.
* cp-namespace.c: Include namespace.h
(cp_add_using_directive): Move to namespace.c, rename it to
add_using_directive, add a "using_directives" argument and use
it as the pending using directives repository. All callers
updated.
* dwarf2read.c (using_directives): New.
(read_import_statement): Call using_directives.
(read_func_scope): Update references to local_using_directives.
(read_lexical_block_scope): Likewise.
(read_namespace): Update the heading comment, call
using_directives.
* namespace.h: New file.
* namespace.c: New file.
* Makefile.in (SFILES): Add namespace.c.
(COMMON_OBS): Add namespace.o
gdb/testsuite/ChangeLog:
* gdb.ada/fun_renaming.exp: New testcase.
* gdb.ada/fun_renaming/fun_renaming.adb: New file.
* gdb.ada/fun_renaming/pack.adb: New file.
* gdb.ada/fun_renaming/pack.ads: New file.
Tested on x86_64-linux. Support for this in GCC is in the pipeline: see
<https://gcc.gnu.org/ml/gcc-patches/2015-07/msg02166.html>.
As Pedro suggested on gdb-patches@ (see
https://sourceware.org/ml/gdb-patches/2015-05/msg00714.html), this
change makes symbol lookup functions return a structure that includes
both the symbol found and the block in which it was found. This makes
it possible to get rid of the block_found global variable and thus makes
block hunting explicit.
gdb/
* ada-exp.y (write_object_renaming): Replace struct
ada_symbol_info with struct block_symbol. Update field
references accordingly.
(block_lookup, select_possible_type_sym): Likewise.
(find_primitive_type): Likewise. Also update call to
ada_lookup_symbol to extract the symbol itself.
(write_var_or_type, write_name_assoc): Likewise.
* ada-lang.h (struct ada_symbol_info): Remove.
(ada_lookup_symbol_list): Replace struct ada_symbol_info with
struct block_symbol.
(ada_lookup_encoded_symbol, user_select_syms): Likewise.
(ada_lookup_symbol): Return struct block_symbol instead of a
mere symbol.
* ada-lang.c (defns_collected): Replace struct ada_symbol_info
with struct block_symbol.
(resolve_subexp, ada_resolve_function, sort_choices,
user_select_syms, is_nonfunction, add_defn_to_vec,
num_defns_collected, defns_collected,
symbols_are_identical_enums, remove_extra_symbols,
remove_irrelevant_renamings, add_lookup_symbol_list_worker,
ada_lookup_symbol_list, ada_iterate_over_symbols,
ada_lookup_encoded_symbol, get_var_value): Likewise.
(ada_lookup_symbol): Return a block_symbol instead of a mere
symbol. Replace struct ada_symbol_info with struct
block_symbol.
(ada_lookup_symbol_nonlocal): Likewise.
(standard_lookup): Make block passing explicit through
lookup_symbol_in_language.
* ada-tasks.c (get_tcb_types_info): Update the calls to
lookup_symbol_in_language to extract the mere symbol out of the
returned value.
(ada_tasks_inferior_data_sniffer): Likewise.
* ax-gdb.c (gen_static_field): Likewise for the call to
lookup_symbol.
(gen_maybe_namespace_elt): Deal with struct symbol_in_block from
lookup functions.
(gen_expr): Likewise.
* c-exp.y: Likewise. Remove uses of block_found.
(lex_one_token, classify_inner_name, c_print_token): Likewise.
(classify_name): Likewise. Rename the "sym" local variable to
"bsym".
* c-valprint.c (print_unpacked_pointer): Likewise.
* compile/compile-c-symbols.c (convert_symbol_sym): Promote the
"sym" parameter from struct symbol * to struct block_symbol.
Use it to remove uses of block_found. Deal with struct
symbol_in_block from lookup functions.
(gcc_convert_symbol): Likewise. Update the call to
convert_symbol_sym.
* compile/compile-object-load.c (compile_object_load): Deal with
struct symbol_in_block from lookup functions.
* cp-namespace.c (cp_lookup_nested_symbol_1,
cp_lookup_nested_symbol, cp_lookup_bare_symbol,
cp_search_static_and_baseclasses,
cp_lookup_symbol_in_namespace, cp_lookup_symbol_via_imports,
cp_lookup_symbol_imports_or_template,
cp_lookup_symbol_via_all_imports, cp_lookup_symbol_namespace,
lookup_namespace_scope, cp_lookup_nonlocal,
find_symbol_in_baseclass): Return struct symbol_in_block instead
of mere symbols and deal with struct symbol_in_block from lookup
functions.
* cp-support.c (inspect_type, replace_typedefs,
cp_lookup_rtti_type): Deal with struct symbol_in_block from
lookup functions.
* cp-support.h (cp_lookup_symbol_nonlocal,
cp_lookup_symbol_from_namespace,
cp_lookup_symbol_imports_or_template, cp_lookup_nested_symbol):
Return struct symbol_in_block instead of mere symbols.
* d-exp.y (d_type_from_name, d_module_from_name, push_variable,
push_module_name):
Deal with struct symbol_in_block from lookup functions. Remove
uses of block_found.
* eval.c (evaluate_subexp_standard): Update call to
cp_lookup_symbol_namespace.
* f-exp.y: Deal with struct symbol_in_block from lookup
functions. Remove uses of block_found.
(yylex): Likewise.
* gdbtypes.c (lookup_typename, lookup_struct, lookup_union,
lookup_enum, lookup_template_type, check_typedef): Deal with
struct symbol_in_block from lookup functions.
* guile/scm-frame.c (gdbscm_frame_read_var): Likewise.
* guile/scm-symbol.c (gdbscm_lookup_symbol): Likewise.
(gdbscm_lookup_global_symbol): Likewise.
* gnu-v3-abi.c (gnuv3_get_typeid_type): Likewise.
* go-exp.y: Likewise. Remove uses of block_found.
(package_name_p, classify_packaged_name, classify_name):
Likewise.
* infrun.c (insert_exception_resume_breakpoint): Likewise.
* jv-exp.y (push_variable): Likewise.
* jv-lang.c (java_lookup_class, get_java_object_type): Likewise.
* language.c (language_bool_type): Likewise.
* language.h (struct language_defn): Update
la_lookup_symbol_nonlocal to return a struct symbol_in_block
rather than a mere symbol.
* linespec.c (find_label_symbols): Deal with struct
symbol_in_block from lookup functions.
* m2-exp.y: Likewise. Remove uses of block_found.
(yylex): Likewise.
* mi/mi-cmd-stack.c (list_args_or_locals): Likewise.
* objc-lang.c (lookup_struct_typedef, find_imps): Likewise.
* p-exp.y: Likewise. Remove uses of block_found.
(yylex): Likewise.
* p-valprint.c (pascal_val_print): Likewise.
* parse.c (write_dollar_variable): Likewise. Remove uses of
block_found.
* parser-defs.h (struct symtoken): Turn the SYM field into a
struct symbol_in_block.
* printcmd.c (address_info): Deal with struct symbol_in_block
from lookup functions.
* python/py-frame.c (frapy_read_var): Likewise.
* python/py-symbol.c (gdbpy_lookup_symbol,
gdbpy_lookup_global_symbol): Likewise.
* skip.c (skip_function_command): Likewise.
* solib-darwin.c (darwin_lookup_lib_symbol): Return a struct
symbol_in_block instead of a mere symbol.
* solib-spu.c (spu_lookup_lib_symbol): Likewise.
* solib-svr4.c (elf_lookup_lib_symbol): Likewise.
* solib.c (solib_global_lookup): Likewise.
* solist.h (solib_global_lookup): Likewise.
(struct target_so_ops): Update lookup_lib_global_symbol to
return a struct symbol_in_block rather than a mere symbol.
* source.c (select_source_symtab): Deal with struct
symbol_in_block from lookup functions.
* stack.c (print_frame_args, iterate_over_block_arg_vars):
Likewise.
* symfile.c (set_initial_language): Likewise.
* symtab.c (SYMBOL_LOOKUP_FAILED): Turn into a struct
symbol_in_block.
(SYMBOL_LOOKUP_FAILED_P): New predicate as a macro.
(struct symbol_cache_slot): Turn the FOUND field into a struct
symbol_in_block.
(block_found): Remove.
(eq_symbol_entry): Update to deal with struct symbol_in_block in
cache slots.
(symbol_cache_lookup): Return a struct symbol_in_block rather
than a mere symbol.
(symbol_cache_mark_found): Add a BLOCK parameter to fill
appropriately the cache slots. Update callers.
(symbol_cache_dump): Update cache slots handling to the type
change.
(lookup_symbol_in_language, lookup_symbol, lookup_language_this,
lookup_symbol_aux, lookup_local_symbol,
lookup_symbol_in_objfile, lookup_global_symbol_from_objfile,
lookup_symbol_in_objfile_symtabs,
lookup_symbol_in_objfile_from_linkage_name,
lookup_symbol_via_quick_fns, basic_lookup_symbol_nonlocal,
lookup_symbol_in_static_block, lookup_static_symbol,
lookup_global_symbol):
Return a struct symbol_in_block rather than a mere symbol. Deal
with struct symbol_in_block from other lookup functions. Remove
uses of block_found.
(lookup_symbol_in_block): Remove uses of block_found.
(struct global_sym_lookup_data): Turn the RESULT field into a
struct symbol_in_block.
(lookup_symbol_global_iterator_cb): Update references to the
RESULT field.
(search_symbols): Deal with struct symbol_in_block from lookup
functions.
* symtab.h (struct symbol_in_block): New structure.
(block_found): Remove.
(lookup_symbol_in_language, lookup_symbol,
basic_lookup_symbol_nonlocal, lookup_symbol_in_static_block,
looku_static_symbol, lookup_global_symbol,
lookup_symbol_in_block, lookup_language_this,
lookup_global_symbol_from_objfile): Return a struct
symbol_in_block rather than just a mere symbol. Update comments
to remove mentions of block_found.
* valops.c (find_function_in_inferior,
value_struct_elt_for_reference, value_maybe_namespace_elt,
value_of_this): Deal with struct symbol_in_block from lookup
functions.
* value.c (value_static_field, value_fn_field): Likewise.
... to avoid a build failure when building with C++ compiler
(when configured with --enable-build-with-cxx). We cannot use
"typename" as it is a C++ reserved keyword.
gdb/ChangeLog:
* ada-lang.c (to_fixed_array_type): Rename local variable
typename into type_name.
In Ada, index types of arrays can be enumeration types, and enumeration
types can be non-contiguous. In which case the address of elements is
not given by the value of the index, but by its position in the enumeration
type.
In other words, in this example:
type Color is (Blue, Red);
for Color use (Blue => 8, Red => 12, Green => 16);
type A is array (Color) of Integer;
type B is array (1 .. 3) of Integer;
Arrays of type A and B will have the same layout in memory, even if
the enumeration Color has a hole in its set of integer value.
Since recently support for such a feature was in ada-lang.c, where the
array was casted to a regular continuous index range. We were losing
the information of index type. And this was not quite working for
subranges in variable-length fields; their bounds are expressed using
the integer value of the bounds, not its position in the enumeration,
and there was some confusion all over ada-lang.c as to whether we had
the position or the integer value was used for indexes.
The idea behind this patch is to clean this up by keeping the real
representation of these array index types and bounds when representing
the value, and only use the position when accessing the elements or
computing the length. This first patch fixes the printing of such
an array.
To the best of my knowledge, this feature only exists in Ada so it
should only affect this language.
gdb/ChangeLog:
Jerome Guitton <guitton@adacore.com>:
* ada-lang.c (ada_value_ptr_subscript): Use enum position of
index to get element instead of enum value.
(ada_value_slice_from_ptr, ada_value_slice): Use enum position
of index to compute length, but enum values to compute bounds.
(ada_array_length): Use enum position of index instead of enum value.
(pos_atr): Move position computation to...
(ada_evaluate_subexp): Use enum values to compute bounds.
* gdbtypes.c (discrete_position): ...this new function.
* gdbtypes.h (discrete_position): New function declaration.
* valprint.c (val_print_array_elements): Call discrete_position
to handle array indexed by non-contiguous enumeration types.
gdb/testsuite/ChangeLog:
* gdb.ada/arr_enum_with_gap: New testcase.
In the case of non bit-packed arrays, GNAT does not generate its
traditional XP encoding; it is not needed. However, it still generates
the so-called "implementation type" with a P suffix. This
implementation type shall be skipped when looking for other
descriptive types such as XA encodings for variable-length
fields.
Note also that there may be an intermediate typedef between the
implementation type and its XA description. It shall be skipped
as well.
gdb/ChangeLog:
Jerome Guitton <guitton@adacore.com>
* ada-lang.c (find_parallel_type_by_descriptive_type):
Go through typedefs during lookup.
(to_fixed_array_type): Add support for non-bit packed arrays
as variable-length fields.
gdb/testsuite/ChangeLog:
* gdb.ada/byte_packed_arr: New testcase.
Consider the following declarations:
type Signed_Small is new Integer range - (2 ** 5) .. (2 ** 5 - 1);
type Signed_Simple_Array is array (1 .. 4) of Signed_Small;
pragma Pack (Signed_Simple_Array);
SSA : Signed_Simple_Array := (-1, 2, -3, 4);
GDB currently print its value incorrectly for the elements that
are negative:
(gdb) print ssa
$1 = (65535, 2, 1048573, 4)
(gdb) print ssa(1)
$2 = 65535
(gdb) print ssa(2)
$3 = 2
(gdb) print ssa(3)
$4 = 1048573
(gdb) print ssa(4)
$5 = 4
What happens is that the sign-extension is not working because
we're trying to do left shift with a negative count. In
ada_value_primitive_packed_val, we have a loop which populates
the extra bits of the target (unpacked) value, after extraction
of the data from the original (packed) value:
while (ntarg > 0)
{
accum |= sign << accumSize;
unpacked[targ] = accum & ~(~0L << HOST_CHAR_BIT);
!!! -> accumSize -= HOST_CHAR_BIT;
accum >>= HOST_CHAR_BIT;
ntarg -= 1;
targ += delta;
}
At each iteration, accumSize gets decremented by HOST_CHAR_BIT,
which can easily cause it to become negative, particularly on
little endian targets, where accumSize is at most HOST_CHAR_BIT - 1.
This causes us to perform a left-shift operation with a negative
accumSize at the next loop iteration, which is undefined, and
acutally does not produce the effect we wanted (value left untouched)
when the code is compiled with GCC.
This patch fixes the issue by simply setting accumSize to zero
if negative.
gdb/ChangeLog:
* ada-lang.c (ada_value_primitive_packed_val): Make sure
accumSize is never negative.
gdb/testsuite/ChangeLog:
* gdb.ada/pckd_neg: New testcase.
We observed on x86-windows that trying to call a function from
GDB leads to a mysterious "Invalid cast" error. This can be
observed in gdb.ada/float_param.exp:
(gdb) call set_long_double(1, global_small_struct, 4.0)
Invalid cast.
This happens because the 3rd parameter, a Long_Long_Float, is
actually passed wrapped inside a PAD structure. As documented
in GNAT's exp_dbug.ads, PAD types are simple wrappers that GNAT
uses to handle types with size or alignment constraints.
We already support those when printing an object encapsulated
in a PAD type, but not when trying to pass an argument that
is wrapped inside a PAD type. As a result, what happens is that
call_function_by_hand ends up with an argument with a type
that looks incompatible with the expected type of the argument.
The error comes when trying to push the arguments in inferior
memory, while trying to coerce each one of them to their expected
types (in value_arg_coerce).
Note that the problem is not specific to Windows, but so far, this is
the only platform where we've seen this happen.
gdb/ChangeLog:
* ada-lang.c (ada_convert_actual): Add handling of formals
passed inside an aligner type.
Tested on x86-windows (AdaCore testsuite) and x86_64-linux (official
testsuite as well as AdaCore's testsuite).
This patch improves the documentation of ada-lang.c's
value_assign_to_component to publish the fact that it also works
with not_lval values.
And touching this area of the code showed that there were a number
of whitespace issues, as well as a formatting issue of the main comment
(no leading '*' on each line). This patch fixes those while at it.
No functional change, however.
gdb/ChangeLog:
* ada-lang.c (value_assign_to_component): Reformat and improve
documentation. Remove all trailing spaces.
This is an issue which I noticed while working on trying to print
an array of variant records. For instance, trying to print "A1",
an array of elements whose size is variable, defined as follow
(see gdb.ada/var_rec_arr testcase):
subtype Small_Type is Integer range 0 .. 10;
type Record_Type (I : Small_Type := 0) is record
S : String (1 .. I);
end record;
function Ident (R : Record_Type) return Record_Type;
type Array_Type is array (Integer range <>) of Record_Type;
A1 : Array_Type := (1 => (I => 0, S => <>),
2 => (I => 1, S => "A"),
3 => (I => 2, S => "AB"));
The debugger sometimes prints the array as follow:
(gdb) print A1
$1 = ((i => 0, s => ""), (i => 0, s => ""), (i => 0, s => ""))
The problem happens inside the part of the loop printing the array's
elements, while trying to count the number of consecutive elements
that have the same value (in order to replace them by the "<repeats
nnn times>" message when the number exceeds a threshold). In particular,
in ada-valprint.c::val_print_packed_array_elements:
elttype = TYPE_TARGET_TYPE (type);
eltlen = TYPE_LENGTH (check_typedef (elttype));
while (...)
{
if (!value_contents_eq (v0, value_embedded_offset (v0),
v1, value_embedded_offset (v1),
eltlen))
break;
The value comparison is performed using value_contents_eq but makes
the assumption that elttype is not dynamic, which is not always true.
In particular, in the case above, elttype is dynamic and therefore
its TYPE_LENGTH changes from element to element.
As it happens in this case, the eltlen is zero, which causes the call
to value_contents_eq to return true, and therefore GDB thinks all
3 elements of the array are equal.
This patch fixes the issue by making sure that both v0 and v1, which
are values whose type we expect to be resolved, have identical lengths.
If not, then the two elements of the array cannot possibly have the
same value and we do not even need to do the binary comparison.
Unfortunately, this is still not enough to get GDB to print the correct
value for our array, because the assumption that v0 and v1 have a type
which has been resolved is actually not met. So, the second part of
the patch modifies the function that constructed the values to make
sure dynamic types do get resolved.
gdb/ChangeLog:
* ada-valprint.c (val_print_packed_array_elements): Delete
variable "len". Add a type-length check when comparing two
consecutive elements of the array. Use the element's actual
length in call to value_contents_eq.
* ada-lang.c (ada_value_primitive_packed_val): Always return
a value whose type has been resolved.
Consider the following declarations:
subtype Small_Type is Integer range 0 .. 10;
type Record_Type (I : Small_Type := 0) is record
S : String (1 .. I);
end record;
A2 : Array_Type := (1 => (I => 2, S => "AB"),
2 => (I => 1, S => "A"),
3 => (I => 0, S => <>));
Compiled with -fgnat-encodings=minimal, and trying to print
one element of our array, valgrind reports an invalid memory
access. On certain GNU/Linux boxes, malloc even reports it as
well, and causes GDB to crash.
(gdb) print a2(1)
*** glibc detected *** /[...]/gdb:
malloc(): memory corruption: 0x0a30ba48 ***
[crash]
The invalid memory access occurs because of a simple buffer
overflow in ada_value_primitive_packed_val. When this function
is called, it is given a bit_size of 128 (or 16 bytes), which
corresponds to the stride of our array. But the actual size of
each element depends on its value. In particular, A2(1) is a record
whose size is only 6 bytes.
What happens in our example is that we start building a new value
(v) where the element is to be unpacked, with any of its dynamic
properties getting resolved as well. We then unpack the data into
this value's buffer:
unpacked = (unsigned char *) value_contents (v);
[...]
nsrc = len;
[...]
while (nsrc > 0)
{
[...]
unpacked[targ] = accum & ~(~0L << HOST_CHAR_BIT);
[...]
targ += delta;
[...]
nsrc -= 1;
[...]
}
In the loop above, targ starts at zero (for LE architectures),
and len is 16. With delta being +1, we end up iterating 16 times,
writing 16 bytes into a 6-bytes buffer.
This patch fixes the issue by adjusting BIT_SIZE and recomputing
LEN after having resolved our type if the resolved type turns out
to be smaller than bit_size.
gdb/ChangeLog:
* ada-lang.c (ada_value_primitive_packed_val): Recompute
BIT_SIZE and LEN if the size of the resolved type is smaller
than BIT_SIZE * HOST_CHAR_BIT.
Consider the following (Ada) array...
A1 : Array_Type := (1 => (I => 0, S => <>),
2 => (I => 1, S => "A"),
3 => (I => 2, S => "AB"));
... where Array_Type is declared as follow:
subtype Small_Type is Integer range 0 .. 10;
type Record_Type (I : Small_Type := 0) is record
S : String (1 .. I);
end record;
type Array_Type is array (Integer range <>) of Record_Type;
Trying to print the value of each element individually does not
always work. Printing the value of the first one does:
(gdb) p a1(1)
$1 = (i => 0, s => "")
But printing the value of the subsequent ones often does not.
For instance:
(gdb) p a1(2)
$2 = (i => 1, s => "") <<<--- s should be "A"
(gdb) p a1(3)
$3 = (i => 2, s => "") <<<--- s should be "AB"
I traced the problem to ada_value_primitive_packed_val,
which is trying to perform the array subscripting by
extracting the value of the corresponding array element
into a buffer where the contents is now byte-aligned.
The element type that ada_value_primitive_packed_val gets passed
is a dynamic type. As it happens, that dynamic type can get resolved
thanks to:
v = value_at (type, value_address (obj));
type = value_type (v);
However, obj represents the array, so the address given in the call
to value_at represents the value of the first element. As a result,
the solution of component S's upper bound always gets resolved based
on the value of component I in the first element of the array, whose
value is 0, thus leading to GDB mistakely resolving the element type
where S's upper bound is always 0.
The proper fix would be to systematically resolve the element type
first. But, this requires us to extract-and-realign the element's
value so as to be able to pass it as "valaddr" to resolve_dynamic_type.
In the meantime, it's easy to make the situation a little better by
passing "value_address (obj) + offset" as the object address. This
only works when BIT_OFFSET is nul, but that should be the case when
the element type is anything but a scalar, which seems to be the only
situation where it seems important to resolve the type now. And we're
not that worse off otherwise.
But we'll try to find a better solution in a separate patch.
gdb/ChangeLog:
* ada-lang.c (ada_value_primitive_packed_val): Use a more
correct address in call to value_at. Adjust call to
value_address accordingly.
This is the second part of enhancing the debugger to print the value
of arrays of records whose size is variable when only standard DWARF
info is available (no GNAT encoding). For instance:
subtype Small_Type is Integer range 0 .. 10;
type Record_Type (I : Small_Type := 0) is record
S : String (1 .. I);
end record;
type Array_Type is array (Integer range <>) of Record_Type;
A1 : Array_Type := (1 => (I => 0, S => <>),
2 => (I => 1, S => "A"),
3 => (I => 2, S => "AB"));
Currently, GDB prints the following output:
(gdb) p a1
$1 = (
The error happens while the ada-valprint module is trying to print
the value of an element of our array. Because of the fact that
the array's element (type Record_Type) has a variant size, the DWARF
info for our array provide the array's stride:
<1><749>: Abbrev Number: 10 (DW_TAG_array_type)
<74a> DW_AT_name : (indirect string, offset: 0xb6d): pck__T18s
<74e> DW_AT_byte_stride : 16
<74f> DW_AT_type : <0x6ea>
And because our array has a stride, ada-valprint treats it the same
way as packed arrays (see ada-valprint.c::ada_val_print_array):
if (TYPE_FIELD_BITSIZE (type, 0) > 0)
val_print_packed_array_elements (type, valaddr, offset_aligned,
0, stream, recurse,
original_value, options);
The first thing that we should notice in the call above is that
the "valaddr" buffer and the associated offset (OFFSET_ALIGNED)
is passed, but that the corresponding array's address is not.
This can be explained by looking inside val_print_packed_array_elements,
where we see that the function unpacks each element of our array from
the buffer alone (ada_value_primitive_packed_val), and then prints
the resulting artificial value instead:
v0 = ada_value_primitive_packed_val (NULL, valaddr + offset,
(i0 * bitsize) / HOST_CHAR_BIT,
(i0 * bitsize) % HOST_CHAR_BIT,
bitsize, elttype);
[...]
val_print (elttype, value_contents_for_printing (v0),
value_embedded_offset (v0), 0, stream,
recurse + 1, v0, &opts, current_language);
Of particular interest, here, is the fact that we call val_print
with a null address, which is OK, since we're providing a buffer
instead (value_contents_for_printing). Also, providing an address
might not always possible, since packing could place elements at
boundaries that are not byte-aligned.
Things go south when val_print tries to see if there is a pretty-printer
that could be applied. In particular, one of the first things that
the Python pretty-printer does is to create a value using our buffer,
and the given address, which in this case is null (see call to
value_from_contents_and_address in gdbpy_apply_val_pretty_printer).
value_from_contents_and_address, in turn immediately tries to resolve
the type, using the given address, which is null. But, because our
array element is a record containing an array whose bound is the value
of one of its elements (the "s" component), the debugging info for
the array's upper bound is a reference...
<3><71a>: Abbrev Number: 7 (DW_TAG_subrange_type)
<71b> DW_AT_type : <0x724>
<71f> DW_AT_upper_bound : <0x703>
... to component "i" of our record...
<2><703>: Abbrev Number: 5 (DW_TAG_member)
<704> DW_AT_name : i
<706> DW_AT_decl_file : 2
<707> DW_AT_decl_line : 6
<708> DW_AT_type : <0x6d1>
<70c> DW_AT_data_member_location: 0
... where that component is located at offset 0 of the start
of the record. dwarf2_evaluate_property correctly determines
the offset where to load the value of the bound from, but then
tries to read that value from inferior memory using the address
that was given, which is null. See case PROP_ADDR_OFFSET in
dwarf2_evaluate_property:
val = value_at (baton->offset_info.type,
pinfo->addr + baton->offset_info.offset);
This triggers a memory error, which then causes the printing to terminate.
Since there are going to be situations where providing an address
alone is not going to be sufficient (packed arrays where array elements
are not stored at byte boundaries), this patch fixes the issue by
enhancing the type resolution to take both address and data. This
follows the same principle as the val_print module, where both
address and buffer ("valaddr") can be passed as arguments. If the data
has already been fetched from inferior memory (or provided by the
debugging info in some form -- Eg a constant), then use that data
instead of reading it from inferior memory.
Note that this should also be a good step towards being able to handle
dynamic types whose value is stored outside of inferior memory
(Eg: in a register).
With this patch, GDB isn't able to print all of A1, but does perform
a little better:
(gdb) p a1
$1 = ((i => 0, s => , (i => 1, s => , (i => 2, s => )
There is another issue which is independent of this one, and will
therefore be patched separately.
gdb/ChangeLog:
* dwarf2loc.h (struct property_addr_info): Add "valaddr" field.
* dwarf2loc.c (dwarf2_evaluate_property): Add handling of
pinfo->valaddr.
* gdbtypes.h (resolve_dynamic_type): Add "valaddr" parameter.
* gdbtypes.c (resolve_dynamic_struct): Set pinfo.valaddr.
(resolve_dynamic_type_internal): Set pinfo.valaddr.
Add handling of addr_stack->valaddr.
(resolve_dynamic_type): Add "valaddr" parameter.
Set pinfo.valaddr field.
* ada-lang.c (ada_discrete_type_high_bound): Update call to
resolve_dynamic_type.
(ada_discrete_type_low_bound): Likewise.
* findvar.c (default_read_var_value): Likewise.
* value.c (value_from_contents_and_address): Likewise.
Currently, ada-lang.c:template_to_static_fixed_type (working on
structure types only) caches its result into the unused TYPE_TARGET_TYPE
field. This introduces inconsistencies when the input type is
specialized, for instance during type resolution: the cached static
fixed type is copied along with the original type, but it's no longer
adapted to the copy once the copy is modified:
template_to_static_fixed_type has to compute another static fixed type
for it.
This change first introduces a cache reset during type resolution for
structure types so that this inconsistency does not happen anymore. It
also makes template_to_static_fixed_type smarter with respect to types
that do not need static fixed copies so that less computations is done
in general.
This inconsistency was spotted thanks to code reading, not because of
any sort of failure and we did not manage to exhibit a failure yet, so
no testcase for this.
gdb/ChangeLog:
* ada-lang.c (template_to_static_fixed_type): Return input type
when it is already fixed. Cache the input type itself when not
creating a static fixed copy. Make it explicit that we never
molestate the input type.
* gdbtypes.c (resolve_dynamic_struct): Reset the
TYPE_TARGET_TYPE field for resolved copies.
Consider the following declarations:
type Int_Access is access Integer;
type Record_Type is record
IA : Int_Access;
end record;
R : Record_Type;
Printing the type name of "R.IA" yields:
(gdb) whatis r.ia
type = access integer
It should be:
(gdb) whatis r.ia
type = bar.int_access
Looking at the debugging info, field "r.ia" is defined as
a typedef which has the name of the field type:
.uleb128 0x3 # (DIE (0x4e) DW_TAG_typedef)
.long .LASF4 # DW_AT_name: "bar__int_access"
.long 0x8b # DW_AT_type
... with the typedef's target type being an anonymous pointer
type:
.uleb128 0x7 # (DIE (0x8b) DW_TAG_pointer_type)
.byte 0x8 # DW_AT_byte_size
.long 0x91 # DW_AT_type
What happens here is that a couple of function in ada-lang.c
always start by stripping all typedef layers when handling
struct fields, with the effect of making us lose the type name
in this case.
We did not understand this at the time the code was written,
but typedefs should be stripped only when we know we do not
need them. So this patch, adjust the code to avoid the stripping
while handling the fields, and adds it back in the lone place
which handles the result of processing and didn't know how to
handle typedefs struct fields yet.
gdb/ChangeLog:
* ada-lang.c (ada_is_tagged_type): Add call to ada_check_typedef.
(ada_lookup_struct_elt_type): Remove calls to ada_check_typedef.
(template_to_static_fixed_type): Call ada_check_typedef only
when necessary.
gdb/testsuite/ChangeLog:
* gdb.ada/rec_comp: New testcase.
This patch splits the TRY_CATCH macro into three, so that we go from
this:
~~~
volatile gdb_exception ex;
TRY_CATCH (ex, RETURN_MASK_ERROR)
{
}
if (ex.reason < 0)
{
}
~~~
to this:
~~~
TRY
{
}
CATCH (ex, RETURN_MASK_ERROR)
{
}
END_CATCH
~~~
Thus, we'll be getting rid of the local volatile exception object, and
declaring the caught exception in the catch block.
This allows reimplementing TRY/CATCH in terms of C++ exceptions when
building in C++ mode, while still allowing to build GDB in C mode
(using setjmp/longjmp), as a transition step.
TBC, after this patch, is it _not_ valid to have code between the TRY
and the CATCH blocks, like:
TRY
{
}
// some code here.
CATCH (ex, RETURN_MASK_ERROR)
{
}
END_CATCH
Just like it isn't valid to do that with C++'s native try/catch.
By switching to creating the exception object inside the CATCH block
scope, we can get rid of all the explicitly allocated volatile
exception objects all over the tree, and map the CATCH block more
directly to C++'s catch blocks.
The majority of the TRY_CATCH -> TRY+CATCH+END_CATCH conversion was
done with a script, rerun from scratch at every rebase, no manual
editing involved. After the mechanical conversion, a few places
needed manual intervention, to fix preexisting cases where we were
using the exception object outside of the TRY_CATCH block, and cases
where we were using "else" after a 'if (ex.reason) < 0)' [a CATCH
after this patch]. The result was folded into this patch so that GDB
still builds at each incremental step.
END_CATCH is necessary for two reasons:
First, because we name the exception object in the CATCH block, which
requires creating a scope, which in turn must be closed somewhere.
Declaring the exception variable in the initializer field of a for
block, like:
#define CATCH(EXCEPTION, mask) \
for (struct gdb_exception EXCEPTION; \
exceptions_state_mc_catch (&EXCEPTION, MASK); \
EXCEPTION = exception_none)
would avoid needing END_CATCH, but alas, in C mode, we build with C90,
which doesn't allow mixed declarations and code.
Second, because when TRY/CATCH are wired to real C++ try/catch, as
long as we need to handle cleanup chains, even if there's no CATCH
block that wants to catch the exception, we need for stop at every
frame in the unwind chain and run cleanups, then rethrow. That will
be done in END_CATCH.
After we require C++, we'll still need TRY/CATCH/END_CATCH until
cleanups are completely phased out -- TRY/CATCH in C++ mode will
save/restore the current cleanup chain, like in C mode, and END_CATCH
catches otherwise uncaugh exceptions, runs cleanups and rethrows, so
that C++ cleanups and exceptions can coexist.
IMO, this still makes the TRY/CATCH code look a bit more like a
newcomer would expect, so IMO worth it even if we weren't considering
C++.
gdb/ChangeLog.
2015-03-07 Pedro Alves <palves@redhat.com>
* common/common-exceptions.c (struct catcher) <exception>: No
longer a pointer to volatile exception. Now an exception value.
<mask>: Delete field.
(exceptions_state_mc_init): Remove all parameters. Adjust.
(exceptions_state_mc): No longer pop the catcher here.
(exceptions_state_mc_catch): New function.
(throw_exception): Adjust.
* common/common-exceptions.h (exceptions_state_mc_init): Remove
all parameters.
(exceptions_state_mc_catch): Declare.
(TRY_CATCH): Rename to ...
(TRY): ... this. Remove EXCEPTION and MASK parameters.
(CATCH, END_CATCH): New.
All callers adjusted.
gdb/gdbserver/ChangeLog:
2015-03-07 Pedro Alves <palves@redhat.com>
Adjust all callers of TRY_CATCH to use TRY/CATCH/END_CATCH
instead.
John Baldwin