The operators FLOOR, CEILING, CMPLX, LBOUND, UBOUND, and SIZE accept
(some only with Fortran 2003) the optional parameter KIND. This
parameter determines the kind of the associated return value. So far,
implementation of this kind parameter has been missing in GDB.
Additionally, the one argument overload for the CMPLX intrinsic function
was not yet available.
This patch adds overloads for all above mentioned functions to the
Fortran intrinsics handling in GDB.
It re-writes the intrinsic function handling section to use the helper
methods wrap_unop_intrinsic/wrap_binop_intrinsic/wrap_triop_intrinsic.
These methods define the action taken when a Fortran intrinsic function
is called with a certain amount of arguments (1/2/3). The helper methods
fortran_wrap2_kind and fortran_wrap3_kind have been added as equivalents
to the existing wrap and wrap2 methods.
After adding more overloads to the intrinsics handling, some of the
operation names were no longer accurate. E.g. UNOP_FORTRAN_CEILING
has been renamed to FORTRAN_CEILING as it is no longer a purely unary
intrinsic function. This patch also introduces intrinsic functions with
one, two, or three arguments to the Fortran parser and the
UNOP_OR_BINOP_OR_TERNOP_INTRINSIC token has been added.
On x86 machines with xmm register, and with recent versions of
systemtap (and gcc?), it can occur that stap probe arguments will be
placed into xmm registers.
I notice this happening on a current Fedora Rawhide install with the
following package versions installed:
$ rpm -q glibc systemtap gcc
glibc-2.35.9000-10.fc37.x86_64
systemtap-4.7~pre16468670g9f253544-1.fc37.x86_64
gcc-12.0.1-0.12.fc37.x86_64
If I check the probe data in libc, I see this:
$ readelf -n /lib64/libc.so.6
...
stapsdt 0x0000004d NT_STAPSDT (SystemTap probe descriptors)
Provider: libc
Name: pthread_start
Location: 0x0000000000090ac3, Base: 0x00000000001c65c4, Semaphore: 0x0000000000000000
Arguments: 8@%xmm1 8@1600(%rbx) 8@1608(%rbx)
stapsdt 0x00000050 NT_STAPSDT (SystemTap probe descriptors)
Provider: libc
Name: pthread_create
Location: 0x00000000000912f1, Base: 0x00000000001c65c4, Semaphore: 0x0000000000000000
Arguments: 8@%xmm1 8@%r13 8@8(%rsp) 8@16(%rsp)
...
Notice that for both of these probes, the first argument is a uint64_t
stored in the xmm1 register.
Unfortunately, if I try to use this probe within GDB, then I can't
view the first argument. Here's an example session:
$ gdb $(which gdb)
(gdb) start
...
(gdb) info probes stap libc pthread_create
...
(gdb) break *0x00007ffff729e2f1 # Use address of probe.
(gdb) continue
...
(gdb) p $_probe_arg0
Invalid cast.
What's going wrong? If I re-run my session, but this time use 'set
debug stap-expression 1', this is what I see:
(gdb) set debug stap-expression 1
(gdb) p $_probe_arg0
Operation: UNOP_CAST
Operation: OP_REGISTER
String: xmm1
Type: uint64_t
Operation: UNOP_CAST
Operation: OP_REGISTER
String: r13
Type: uint64_t
Operation: UNOP_CAST
Operation: UNOP_IND
Operation: UNOP_CAST
Operation: BINOP_ADD
Operation: OP_LONG
Type: long
Constant: 0x0000000000000008
Operation: OP_REGISTER
String: rsp
Type: uint64_t *
Type: uint64_t
Operation: UNOP_CAST
Operation: UNOP_IND
Operation: UNOP_CAST
Operation: BINOP_ADD
Operation: OP_LONG
Type: long
Constant: 0x0000000000000010
Operation: OP_REGISTER
String: rsp
Type: uint64_t *
Type: uint64_t
Invalid cast.
(gdb)
The important bit is this:
Operation: UNOP_CAST
Operation: OP_REGISTER
String: xmm1
Type: uint64_t
Which is where we cast the xmm1 register to uint64_t. And the final
piece of the puzzle is:
(gdb) ptype $xmm1
type = union vec128 {
v8bf16 v8_bfloat16;
v4f v4_float;
v2d v2_double;
v16i8 v16_int8;
v8i16 v8_int16;
v4i32 v4_int32;
v2i64 v2_int64;
uint128_t uint128;
}
So, we are attempting to cast a union type to a scalar type, which is
not supporting in C/C++, and as a consequence GDB's expression
evaluator throws an error when we attempt to do this.
The first approach I considered for solving this problem was to try
and make use of gdbarch_stap_adjust_register. We already have a
gdbarch method (gdbarch_stap_adjust_register) that allows us to tweak
the name of the register that we access. Currently only x86
architectures use this to transform things like ax to eax in some
cases.
I wondered, what if we change gdbarch_stap_adjust_register to do more
than just change the register names? What if this method instead
became gdbarch_stap_read_register. This new method would return a
operation_up, and would take the register name, and the type we are
trying to read from the register, and return the operation that
actually reads the register.
The default implementation of this method would just use
user_reg_map_name_to_regnum, and then create a register_operation,
like we already do in stap_parse_register_operand. But, for x86
architectures this method would fist possibly adjust the register
name, then do the default action to read the register. Finally, for
x86 this method would spot when we were accessing an xmm register,
and, based on the type being pulled from the register, would extract
the correct field from the union.
The benefit of this approach is that it would work with the expression
types that GDB currently supports. The draw back would be that this
approach would not be very generic. We'd need code to handle each
sub-field size with an xmm register. If other architectures started
using vector registers for probe arguments, those architectures would
have to create their own gdbarch_stap_read_register method. And
finally, the type of the xmm registers comes from the type defined in
the target description, there's a risk that GDB might end up
hard-coding the names of type sub-fields, then if a target uses a
different target description, with different field names for xmm
registers, the stap probes would stop working.
And so, based on all the above draw backs, I rejected this first
approach.
My second plan involves adding a new expression type to GDB called
unop_extract_operation. This new expression takes a value and a type,
during evaluation the value contents are fetched, and then a new value
is extracted from the value contents (based on type). This is similar
to the following C expression:
result_value = *((output_type *) &input_value);
Obviously we can't actually build this expression in this case, as the
input_value is in a register, but hopefully the above makes it clearer
what I'm trying to do.
The benefit of the new expression approach is that this code can be
shared across all architectures, and it doesn't care about sub-field
names within the union type.
The draw-backs that I see are potential future problems if arguments
are not stored within the least significant bytes of the register.
However if/when that becomes an issue we can adapt the
gdbarch_stap_read_register approach to allow architectures to control
how a value is extracted.
For testing, I've extended the existing gdb.base/stap-probe.exp test
to include a function that tries to force an argument into an xmm
register. Obviously, that will only work on a x86 target, so I've
guarded the new function with an appropriate GCC define. In the exp
script we use readelf to check if the probe exists, and is using the
xmm register.
If the probe doesn't exist then the associated tests are skipped.
If the probe exists, put isn't using the xmm register (which will
depend on systemtap/gcc versions), then again, the tests are skipped.
Otherwise, we can run the test. I think the cost of running readelf
is pretty low, so I don't feel too bad making all the non-xmm targets
running this step.
I found that on a Fedora 35 install, with these packages installed, I
was able to run this test and have the probe argument be placed in an
xmm register:
$ rpm -q systemtap gcc glibc
systemtap-4.6-4.fc35.x86_64
gcc-11.2.1-9.fc35.x86_64
glibc-2.34-7.fc35.x86_64
Finally, as this patch adds a new operation type, then I need to
consider how to generate an agent expression for the new operation
type.
I have kicked the can down the road a bit on this. In the function
stap_parse_register_operand, I only create a unop_extract_operation in
the case where the register type is non-scalar, this means that in
most cases I don't need to worry about generating an agent expression
at all.
In the xmm register case, when an unop_extract_operation will be
created, I have sketched out how the agent expression could be
handled, however, this code is currently not reached. When we try to
generate the agent expression to place the xmm register on the stack,
GDB hits this error:
(gdb) trace -probe-stap test:xmmreg
Tracepoint 1 at 0x401166
(gdb) actions
Enter actions for tracepoint 1, one per line.
End with a line saying just "end".
>collect $_probe_arg0
Value not scalar: cannot be an rvalue.
This is because GDB doesn't currently support placing non-scalar types
on the agent expression evaluation stack. Solving this is clearly
related to the original problem, but feels a bit like a second
problem. I'd like to get feedback on whether my approach to solving
the original problem is acceptable or not before I start looking at
how to handle xmm registers within agent expressions.
This commit brings all the changes made by running gdb/copyright.py
as per GDB's Start of New Year Procedure.
For the avoidance of doubt, all changes in this commits were
performed by the script.
LOC(X) returns the address of X as an integer:
https://gcc.gnu.org/onlinedocs/gfortran/LOC.html
Before:
(gdb) p LOC(r)
No symbol "LOC" in current context.
After:
(gdb) p LOC(r)
$1 = 0xffffdf48
gdb/ChangeLog:
2021-03-09 Felix Willgerodt <felix.willgerodt@intel.com>
* f-exp.h (eval_op_f_loc): Declare.
(expr::fortran_loc_operation): New typedef.
* f-exp.y (exp): Handle UNOP_FORTRAN_LOC after parsing an
UNOP_INTRINSIC.
(f77_keywords): Add LOC keyword.
* f-lang.c (eval_op_f_loc): New function.
* std-operator.def (UNOP_FORTRAN_LOC): New operator.
gdb/testsuite/ChangeLog:
2020-03-09 Felix Willgerodt <felix.willgerodt@intel.com>
* gdb.fortran/intrinsics.exp: Add LOC tests.
Add support for the SHAPE keyword to GDB's Fortran expression parser.
gdb/ChangeLog:
* f-exp.h (eval_op_f_array_shape): Declare.
(fortran_array_shape_operation): New type.
* f-exp.y (exp): Handle UNOP_FORTRAN_SHAPE after parsing
UNOP_INTRINSIC.
(f77_keywords): Add "shape" keyword.
* f-lang.c (fortran_array_shape): New function.
(eval_op_f_array_shape): New function.
* std-operator.def (UNOP_FORTRAN_SHAPE): New operator.
gdb/testsuite/ChangeLog:
* gdb.fortran/shape.exp: New file.
* gdb.fortran/shape.f90: New file.
Add support for the 'SIZE' keyword to the Fortran expression parser.
This returns the number of elements either in an entire array (passing
a single argument to SIZE), or in a particular dimension of an
array (passing two arguments to SIZE).
At this point I have not added support for the optional third argument
to SIZE, which controls the exact integer type of the result.
gdb/ChangeLog:
* f-exp.y (eval_op_f_array_size): Declare 1 and 2 argument forms
of this function.
(expr::fortran_array_size_1arg): New type.
(expr::fortran_array_size_2arg): Likewise.
* f-exp.y (exp): Handle FORTRAN_ARRAY_SIZE after parsing
UNOP_OR_BINOP_INTRINSIC.
(f77_keywords): Add "size" keyword.
* f-lang.c (fortran_array_size): New function.
(eval_op_f_array_size): New function, has a 1 arg and 2 arg form.
* std-operator.def (FORTRAN_ARRAY_SIZE): New operator.
gdb/testsuite/ChangeLog:
* gdb.fortran/size.exp: New file.
* gdb.fortran/size.f90: New file.
gfortran supports the RANK keyword, see:
https://gcc.gnu.org/onlinedocs/gfortran/RANK.html#RANK
this commit adds support for this keyword to GDB's Fortran expression
parser.
gdb/ChangeLog:
* f-exp.h (eval_op_f_rank): Declare.
(expr::fortran_rank_operation): New typedef.
* f-exp.y (exp): Handle UNOP_FORTRAN_RANK after parsing an
UNOP_INTRINSIC.
(f77_keywords): Add "rank" keyword.
* f-lang.c (eval_op_f_rank): New function.
* std-operator.def (UNOP_FORTRAN_RANK): New operator.
gdb/testsuite/ChangeLog:
* gdb.fortran/rank.exp: New file.
* gdb.fortran/rank.f90: New file.
BINOP_END is used only as a "meaningless" value in various tables.
This patch changes these to use OP_NULL instead, and removes
BINOP_END.
gdb/ChangeLog
2021-03-08 Tom Tromey <tom@tromey.com>
* std-operator.def (BINOP_END): Remove.
* p-exp.y (tokentab3, tokentab2): Use OP_NULL, not BINOP_END.
* go-exp.y (tokentab2): Use OP_NULL, not BINOP_END.
* f-exp.y (dot_ops, f77_keywords): Use OP_NULL, not BINOP_END.
* d-exp.y (tokentab2, ident_tokens): Use OP_NULL, not BINOP_END.
* c-exp.y (tokentab3, tokentab2, ident_tokens): Use OP_NULL, not
BINOP_END.
OP_EXTENDED0 was only used for an assertion in the code to rewrite an
expression into prefix form. That code is gone, so this patch removes
the constant.
gdb/ChangeLog
2021-03-08 Tom Tromey <tom@tromey.com>
* std-operator.def (OP_EXTENDED0): Remove.
Several Ada expression opcodes are now unused, and can be removed.
Most of these are handled in a different way by the code.
OP_ATR_IMAGE, however, was never implemented.
gdb/ChangeLog
2021-03-08 Tom Tromey <tom@tromey.com>
* std-operator.def (OP_NAME, OP_ATR_IMAGE, OP_ATR_MODULUS)
(OP_OTHERS, OP_CHOICES, OP_POSITIONAL, OP_DISCRETE_RANGE):
Remove.
As noted in an earlier patch, Modula-2 defined some opcodes but then
never implemented them. This patch removes the unnecessary constants.
gdb/ChangeLog
2021-03-08 Tom Tromey <tom@tromey.com>
* std-operator.def (UNOP_CAP, UNOP_CHR, UNOP_ORD, UNOP_FLOAT)
(UNOP_MAX, UNOP_MIN, UNOP_ODD, UNOP_TRUNC, OP_M2_STRING): Remove.
The OP_ATR_MIN and OP_ATR_MAX constants aren't truly needed.
Internally, they are converted to BINOP_MIN and BINOP_MAX. This patch
removes them in favor of simple reuse.
gdb/ChangeLog
2021-03-08 Tom Tromey <tom@tromey.com>
* std-operator.def (OP_ATR_MIN, OP_ATR_MAX): Remove.
* ada-lang.c (ada_binop_minmax): Update.
* ada-exp.h (ada_binop_min_operation, ada_binop_max_operation):
Use BINOP_MIN and BINOP_MAX.
This commit adds support for the ASSOCIATED builtin to the Fortran
expression evaluator. The ASSOCIATED builtin takes one or two
arguments.
When passed a single pointer argument GDB returns a boolean indicating
if the pointer is associated with anything.
When passed two arguments the second argument should either be some a
pointer could point at or a second pointer.
If the second argument is a pointer target, then the result from
associated indicates if the pointer is pointing at this target.
If the second argument is another pointer, then the result from
associated indicates if the two pointers are pointing at the same
thing.
gdb/ChangeLog:
* f-exp.y (f77_keywords): Add 'associated'.
* f-lang.c (fortran_associated): New function.
(evaluate_subexp_f): Handle FORTRAN_ASSOCIATED.
(operator_length_f): Likewise.
(print_unop_or_binop_subexp_f): New function.
(print_subexp_f): Make use of print_unop_or_binop_subexp_f for
FORTRAN_ASSOCIATED, FORTRAN_LBOUND, and FORTRAN_UBOUND.
(dump_subexp_body_f): Handle FORTRAN_ASSOCIATED.
(operator_check_f): Likewise.
* std-operator.def: Add FORTRAN_ASSOCIATED.
gdb/testsuite/ChangeLog:
* gdb.fortran/associated.exp: New file.
* gdb.fortran/associated.f90: New file.
Add support for the LBOUND and UBOUND built in functions to the
Fortran expression parser.
Both support taking one or two arguments. A single argument, which
must be an array, returns an array containing all of the lower or
upper bound data.
When passed two arguments, the second argument is the dimension being
asked about. In this case the result is a scalar containing the lower
or upper bound just for that dimension.
Some examples of usage taken from the new test:
# Given:
# integer, dimension (-8:-1,-10:-2) :: neg_array
#
(gdb) p lbound (neg_array)
$1 = (-8, -10)
(gdb) p lbound (neg_array, 1)
$3 = -8
(gdb) p lbound (neg_array, 2)
$5 = -10
gdb/ChangeLog:
* f-exp.y (UNOP_OR_BINOP_INTRINSIC): New token.
(exp): New pattern using UNOP_OR_BINOP_INTRINSIC.
(one_or_two_args): New pattern.
(f77_keywords): Add lbound and ubound.
* f-lang.c (fortran_bounds_all_dims): New function.
(fortran_bounds_for_dimension): New function.
(evaluate_subexp_f): Handle FORTRAN_LBOUND and FORTRAN_UBOUND.
(operator_length_f): Likewise.
(print_subexp_f): Likewise.
(dump_subexp_body_f): Likewise.
(operator_check_f): Likewise.
* std-operator.def (FORTRAN_LBOUND): Define.
(FORTRAN_UBOUND): Define.
gdb/testsuite/ChangeLog:
* gdb.fortran/lbound-ubound.F90: New file.
* gdb.fortran/lbound-ubound.exp: New file.
This commits the result of running gdb/copyright.py as per our Start
of New Year procedure...
gdb/ChangeLog
Update copyright year range in copyright header of all GDB files.
This removes ada-operator.def and fortran-operator.def, merging their
contents into std-operator.def.
Note that the comment for OP_EXTENDED0 is a bit wrong. IMO this
constant could be removed, as it is only used for a single assert that
does not provide much value. However, I haven't done so here.
gdb/ChangeLog
2020-12-09 Tom Tromey <tromey@adacore.com>
* expprint.c (op_name): Update.
* expression.h (enum exp_opcode): Update.
* std-operator.def: Add more opcodes.
* ada-operator.def, fortran-operator.def: Remove, moving contents
into std-operator.def.
The Fortran specific OP_F77_UNDETERMINED_ARGLIST is currently handled
in the generic expression handling code. There's no reason why this
should be the case, so this commit moves handling of this into Fortran
specific files.
There should be no user visible changes after this commit.
gdb/ChangeLog:
* eval.c: Remove 'f-lang.h' include.
(value_f90_subarray): Moved to f-lang.c.
(eval_call): Renamed to...
(evaluate_subexp_do_call): ...this, is no longer static, header
comment moved into header file.
(evaluate_funcall): Update call to eval_call.
(skip_undetermined_arglist): Moved to f-lang.c.
(fortran_value_subarray): Likewise.
(evaluate_subexp_standard): OP_F77_UNDETERMINED_ARGLIST handling
moved to evaluate_subexp_f.
(calc_f77_array_dims): Moved to f-lang.c
* expprint.c (print_subexp_funcall): New function.
(print_subexp_standard): OP_F77_UNDETERMINED_ARGLIST handling
moved to print_subexp_f, OP_FUNCALL uses new function.
(dump_subexp_body_funcall): New function.
(dump_subexp_body_standard): OP_F77_UNDETERMINED_ARGLIST handling
moved to dump_subexp_f, OP_FUNCALL uses new function.
* expression.h (evaluate_subexp_do_call): Declare.
* f-lang.c (value_f90_subarray): Moved from eval.c.
(skip_undetermined_arglist): Likewise.
(calc_f77_array_dims): Likewise.
(fortran_value_subarray): Likewise.
(evaluate_subexp_f): Add OP_F77_UNDETERMINED_ARGLIST support.
(operator_length_f): Likewise.
(print_subexp_f): Likewise.
(dump_subexp_body_f): Likewise.
* fortran-operator.def (OP_F77_UNDETERMINED_ARGLIST): Move
declaration of this operation to here.
* parse.c (operator_length_standard): OP_F77_UNDETERMINED_ARGLIST
support moved to operator_length_f.
* parser-defs.h (dump_subexp_body_funcall): Declare.
(print_subexp_funcall): Declare.
* std-operator.def (OP_F77_UNDETERMINED_ARGLIST): Moved to
fortran-operator.def.
Future commits will add more Fortran specific expression operators.
In preparation for these new operators, this commit adds a new
fortran-operator.def file similar to how GDB already has
ada-operator.def.
I've moved UNOP_KIND the Fortran specific operator I introduced in
commit 4d00f5d8f6 into this file, and renamed it to make it clearer
that the operator is Fortran specific. I've then updated the Fortran
exp_descriptor table (exp_descriptor_f) to use entirely Fortran
specific functions that now handle UNOP_FORTRAN_KIND (the new name for
UNOP_KIND).
There should be no visible changes for standard users after this
commit, though for developers, the output when 'set debug expression
1' is now better, before:
(gdb) p kind (l1)
Dump of expression @ 0x2ccc7a0, before conversion to prefix form:
Language fortran, 5 elements, 16 bytes each.
Index Opcode Hex Value String Value
0 OP_VAR_VALUE 42 *...............
1 OP_NULL 47730176 .N..............
2 BINOP_INTDIV 47729184 J..............
3 OP_VAR_VALUE 42 *...............
4 UNOP_KIND 78 N...............
Dump of expression @ 0x2ccc7a0, after conversion to prefix form:
Expression: `Invalid expression
(gdb)
and after:
(gdb) p kind (l1)
Dump of expression @ 0x294d0b0, before conversion to prefix form:
Language fortran, 5 elements, 16 bytes each.
Index Opcode Hex Value String Value
0 OP_VAR_VALUE 40 (...............
1 unknown opcode: 224 44088544 ................
2 unknown opcode: 208 44087504 ................
3 OP_VAR_VALUE 40 (...............
4 UNOP_FORTRAN_KIND 119 w...............
Dump of expression @ 0x294d0b0, after conversion to prefix form:
Expression: `KIND(test::l1)'
Language fortran, 5 elements, 16 bytes each.
0 UNOP_FORTRAN_KIND
1 OP_VAR_VALUE Block @0x2a0bce0, symbol @0x2a0b8d0 (l1)
$1 = 1
(gdb)
gdb/ChangeLog:
* gdb/expprint.c (dump_subexp_body_standard): Remove use of
UNOP_KIND.
* gdb/expression.h (exp_opcode): Include 'fortran-operator.def'.
* gdb/f-exp.y (exp): Rename UNOP_KIND to UNOP_FORTRAN_KIND.
* gdb/f-lang.c (evaluate_subexp_f): Likewise.
(operator_length_f): New fuction.
(print_subexp_f): New function.
(op_name_f): New function.
(dump_subexp_body_f): New function.
(operator_check_f): New function.
(exp_descriptor_f): Replace standard expression handling functions
with new functions.
* gdb/fortran-operator.def: New file.
* gdb/parse.c (operator_length_standard): Remove use of UNOP_KIND.
* gdb/std-operator.def: Remove UNOP_KIND.
What appears to be a stray double quote character in std-operator.def
causes incorrect highlighting in my editor.
The quote was introduced in this commit:
commit 858be34c5a
Date: Mon Sep 4 20:21:15 2017 +0100
Handle "p S::method()::static_var" in the C++ parser
I can't see any reason why the quote should be there, so this commit
removes it.
gdb/ChangeLog:
* std-operator.def: Remove unbalanced, stray double quote
character.
The 'kind' keyword has two uses in Fortran, it is the name of a
builtin intrinsic function, and it is also a keyword used to create a
type of a specific kind.
This commit adds support for using kind as an intrinsic function, and
also adds some initial support for using kind to create types of a
specific kind.
This commit only allows the creation of the type 'character(kind=1)',
however, it will be easy enough to extend this in future to support
more type kinds.
The kind of any expression can be queried using the kind intrinsic
function. At the moment the kind returned corresponds to the size of
the type, this matches how gfortran handles kinds. However, the
correspondence between kind and type size depends on the compiler
and/or the specific target, so this might not be correct for
everyone. If we want to support different compilers/targets in future
the code to compute the kind from a type will need to be updated.
gdb/ChangeLog:
* expprint.c (dump_subexp_body_standard): Support UNOP_KIND.
* f-exp.y: Define 'KIND' token.
(exp): New pattern for KIND expressions.
(ptype): Handle types with a kind extension.
(direct_abs_decl): Extend to spot kind extensions.
(f77_keywords): Add 'kind' to the list.
(push_kind_type): New function.
(convert_to_kind_type): New function.
* f-lang.c (evaluate_subexp_f): Support UNOP_KIND.
* parse.c (operator_length_standard): Likewise.
* parser-defs.h (enum type_pieces): Add tp_kind.
* std-operator.def: Add UNOP_KIND.
gdb/testsuite/ChangeLog:
* gdb.fortran/intrinsics.exp: New file.
* gdb.fortran/intrinsics.f90: New file.
* gdb.fortran/type-kinds.exp: New file.
This commit applies all changes made after running the gdb/copyright.py
script.
Note that one file was flagged by the script, due to an invalid
copyright header
(gdb/unittests/basic_string_view/element_access/char/empty.cc).
As the file was copied from GCC's libstdc++-v3 testsuite, this commit
leaves this file untouched for the time being; a patch to fix the header
was sent to gcc-patches first.
gdb/ChangeLog:
Update copyright year range in all GDB files.
This adds alignof and _Alignof to the C/C++ expression parser, and
adds new tests to test the features. The tests are written to try to
ensure that gdb's knowledge of alignment rules stays in sync with the
compiler's.
2018-04-30 Tom Tromey <tom@tromey.com>
PR exp/17095:
* NEWS: Update.
* std-operator.def (UNOP_ALIGNOF): New operator.
* expprint.c (dump_subexp_body_standard) <case UNOP_ALIGNOF>:
New.
* eval.c (evaluate_subexp_standard) <case UNOP_ALIGNOF>: New.
* c-lang.c (c_op_print_tab): Add alignof.
* c-exp.y (ALIGNOF): New token.
(exp): Add "ALIGNOF" production.
(ident_tokens): Add _Alignof and alignof.
2018-04-30 Tom Tromey <tom@tromey.com>
PR exp/17095:
* gdb.dwarf2/dw2-align.exp: New file.
* gdb.cp/align.exp: New file.
* gdb.base/align.exp: New file.
* lib/gdb.exp (gdb_int128_helper): New proc.
(has_int128_c, has_int128_cxx): New caching procs.
When parsing floating-point literals, the language parsers currently
use parse_float or some equivalent routine to parse the input string
into a DOUBLEST, which is then stored within a OP_DOUBLE expression
node. When evaluating the expression, the OP_DOUBLE is finally
converted into a value in target format.
On the other hand, *decimal* floating-point literals are parsed
directly into target format and stored that way in a OP_DECFLOAT
expression node. In order to eliminate the DOUBLEST, this patch
therefore unifies the handling of binary and decimal floating-
point literals and stores them both in target format within a
new OP_FLOAT expression node, replacing both OP_DOUBLE and
OP_DECFLOAT.
In order to store literals in target format, the parse_float
routine needs to know the type of the literal. All parsers
therefore need to be changed to determine the appropriate type
(e.g. by detecting suffixes) *before* calling parse_float,
instead of after it as today. However, this change is mostly
straightforward -- again, this is already done for decimal FP
today.
The core of the literal parsing is moved into a new routine
floatformat_from_string, mirroring floatformat_to_string.
The parse_float routine now calls either floatformat_from_string
or decimal_from_sting, allowing it to handle any type of FP
literal.
All language parsers need to be updated. Some notes on
specific changes to the various languages:
- C: Decimal FP is now handled in parse_float, and no longer
needs to be handled specially.
- D: Straightforward.
- Fortran: Still used a hard-coded "atof", also replaced by
parse_float now. Continues to always use builtin_real_s8
as the type of literal, even though this is probably wrong.
- Go: This used to handle "f" and "l" suffixes, even though
the Go language actually doesn't support those. I kept this
support for now -- maybe revisit later. Note the the GDB
test suite for some reason actually *verifies* that GDB supports
those unsupported suffixes ...
- Pascal: Likewise -- this handles suffixes that are not
supported in the language standard.
- Modula-2: Like Fortran, used to use "atof".
- Rust: Mostly straightforward, except for a unit-testing hitch.
The code use to set a special "unit_testing" flag which would
cause "rust_type" to always return NULL. This makes it not
possible to encode a literal into target format (which type?).
The reason for this flag appears to have been that during
unit testing, there is no "rust_parser" context set up, which
means no "gdbarch" is available to use its types. To fix this,
I removed the unit_testing flag, and instead simply just set up
a dummy rust_parser context during unit testing.
- Ada: This used to check sizeof (DOUBLEST) to determine which
type to use for floating-point literal. This seems questionable
to begin with (since DOUBLEST is quite unrelated to target formats),
and in any case we need to get rid of DOUBLEST. I'm now simply
always using the largest type (builtin_long_double).
gdb/ChangeLog:
2017-10-25 Ulrich Weigand <uweigand@de.ibm.com>
* doublest.c (floatformat_from_string): New function.
* doublest.h (floatformat_from_string): Add prototype.
* std-operator.def (OP_DOUBLE, OP_DECFLOAT): Remove, replace by ...
(OP_FLOAT): ... this.
* expression.h: Do not include "doublest.h".
(union exp_element): Replace doubleconst and decfloatconst by
new element floatconst.
* ada-lang.c (resolve_subexp): Handle OP_FLOAT instead of OP_DOUBLE.
(ada_evaluate_subexp): Likewise.
* eval.c (evaluate_subexp_standard): Handle OP_FLOAT instead of
OP_DOUBLE and OP_DECFLOAT.
* expprint.c (print_subexp_standard): Likewise.
(dump_subexp_body_standard): Likewise.
* breakpoint.c (watchpoint_exp_is_const): Likewise.
* parse.c: Include "dfp.h".
(write_exp_elt_dblcst, write_exp_elt_decfloatcst): Remove.
(write_exp_elt_floatcst): New function.
(operator_length_standard): Handle OP_FLOAT instead of OP_DOUBLE
and OP_DECFLOAT.
(operator_check_standard): Likewise.
(parse_float): Do not accept suffix. Take type as input. Return bool.
Return target format buffer instead of host DOUBLEST.
Use floatformat_from_string and decimal_from_string to parse
either binary or decimal floating-point types.
(parse_c_float): Remove.
* parser-defs.h: Do not include "doublest.h".
(write_exp_elt_dblcst, write_exp_elt_decfloatcst): Remove.
(write_exp_elt_floatcst): Add prototype.
(parse_float): Update prototype.
(parse_c_float): Remove.
* c-exp.y: Do not include "dfp.h".
(typed_val_float): Use byte buffer instead of DOUBLEST.
(typed_val_decfloat): Remove.
(DECFLOAT): Remove.
(FLOAT): Use OP_FLOAT and write_exp_elt_floatcst.
(parse_number): Update to new parse_float interface.
Parse suffixes and determine type before calling parse_float.
Handle decimal and binary FP types the same way.
* d-exp.y (typed_val_float): Use byte buffer instead of DOUBLEST.
(FLOAT_LITERAL): Use OP_FLOAT and write_exp_elt_floatcst.
(parse_number): Update to new parse_float interface.
Parse suffixes and determine type before calling parse_float.
* f-exp.y: Replace dval by typed_val_float.
(FLOAT): Use OP_FLOAT and write_exp_elt_floatcst.
(parse_number): Use parse_float instead of atof.
* go-exp.y (typed_val_float): Use byte buffer instead of DOUBLEST.
(parse_go_float): Remove.
(FLOAT): Use OP_FLOAT and write_exp_elt_floatcst.
(parse_number): Call parse_float instead of parse_go_float.
Parse suffixes and determine type before calling parse_float.
* p-exp.y (typed_val_float): Use byte buffer instead of DOUBLEST.
(FLOAT): Use OP_FLOAT and write_exp_elt_floatcst.
(parse_number): Update to new parse_float interface.
Parse suffixes and determine type before calling parse_float.
* m2-exp.y: Replace dval by byte buffer val.
(FLOAT): Use OP_FLOAT and write_exp_elt_floatcst.
(parse_number): Call parse_float instead of atof.
* rust-exp.y (typed_val_float): Use byte buffer instead of DOUBLEST.
(lex_number): Call parse_float instead of strtod.
(ast_dliteral): Use OP_FLOAT instead of OP_DOUBLE.
(convert_ast_to_expression): Handle OP_FLOAT instead of OP_DOUBLE.
Use write_exp_elt_floatcst.
(unit_testing): Remove static variable.
(rust_type): Do not check unit_testing.
(rust_lex_tests): Do not set uint_testing. Set up dummy rust_parser.
* ada-exp.y (type_float, type_double): Remove.
(typed_val_float): Use byte buffer instead of DOUBLEST.
(FLOAT): Use OP_FLOAT and write_exp_elt_floatcst.
* ada-lex.l (processReal): Use parse_float instead of sscanf.
While the previous commit made "p method()::static_var" (no
single-quotes) Just Work, if users (or frontends) try wrapping the
expression with quotes, they'll get:
(gdb) p 'S::method()::static_var'
'S::method()::static_var' has unknown type; cast it to its declared type
even if we _do_ have debug info for that variable. That's better than
the bogus/confusing value what GDB would print before the
stop-assuming-int patch:
(gdb) p 'S::method()::static_var'
$1 = 1
but I think it'd still be nice to make this case Just Work too.
In this case, due to the quoting, the C/C++ parser (c-exp.y)
interprets the whole expression/string as a single symbol name, and we
end up calling lookup_symbol on that name. There's no debug symbol
with that fully-qualified name, but since the compiler gives the
static variable a mangled linkage name exactly like the above, it
appears in the mininal symbols:
$ nm -A local-static | c++filt | grep static_var
local-static:0000000000601040 d S::method()::static_var
... and that's what GDB happens to find/print. This only happens in
C++, note, since for C the compiler uses different linkage names:
local-static-c:0000000000601040 d static_var.1848
So while (in C++, not C) function local static variables are given a
mangled name that demangles to the same syntax that GDB
documents/expects as the way to access function local statics, there's
no global symbol in the debug info with that name at all. The debug
info for a static local variable for a non-inline function looks like
this:
<1><2a1>: Abbrev Number: 19 (DW_TAG_subprogram)
...
<2><2f7>: Abbrev Number: 20 (DW_TAG_variable)
<2f8> DW_AT_name : (indirect string, offset: 0x4e9): static_var
<2fc> DW_AT_decl_file : 1
<2fd> DW_AT_decl_line : 64
<2fe> DW_AT_type : <0x25>
<302> DW_AT_location : 9 byte block: 3 40 10 60 0 0 0 0 0 (DW_OP_addr: 601040)
and for an inline function, it looks like this (linkage name run
through c++filt for convenience):
<2><21b>: Abbrev Number: 16 (DW_TAG_variable)
<21c> DW_AT_name : (indirect string, offset: 0x21a): static_var
<220> DW_AT_decl_file : 1
<221> DW_AT_decl_line : 48
<222> DW_AT_linkage_name: (indirect string, offset: 0x200): S::inline_method()::static_var
<226> DW_AT_type : <0x25>
<22a> DW_AT_external : 1
<22a> DW_AT_location : 9 byte block: 3 a0 10 60 0 0 0 0 0 (DW_OP_addr: 6010a0)
(The inline case makes the variable external so that the linker can
merge the different inlined copies. It seems like GCC never outputs
the linkage name for non-extern globals.)
When we read the DWARF, we record the static_var variable as a regular
variable of the containing function's block. This makes stopping in
the function and printing the variable as usual. The variable just so
happens to have a memory address as location.
So one way to make "p 'S::method()::static_var'" work would be to
record _two_ copies of the symbols for these variables. One in the
function's scope/block, with "static_var" as name, as we currently do,
and another in the static or global blocks (depending on whether the
symbol is external), with a fully-qualified name. I wrote a prototype
patch for that, and it works. For the non-inline case above, since
the debug info doesn't point to the linkage same, that patch built the
physname of the static local variable as the concat of the physname of
the containing function, plus "::", plus the variable's name. We
could make that approach work for C too, though it kind of feels
awkward to record fake symbol names like that in C.
The other approach I tried is to change the C++ symbol lookup routines
instead. This is the approach this commit takes. We can already
lookup up symbol in namespaces and classes, so this feels like a good
fit, and was easy enough. The advantage is that this doesn't require
recording extra symbols.
The test in gdb.cp/m-static.exp that exposed the need for this is
removed, since the same functionality is now covered by
gdb.cp/local-static.exp.
gdb/ChangeLog:
2017-09-04 Pedro Alves <palves@redhat.com>
* cp-namespace.c (cp_search_static_and_baseclasses): Handle
function/method scopes; lookup the nested name as a function local
static variable.
gdb/testsuite/ChangeLog:
2017-09-04 Pedro Alves <palves@redhat.com>
* gdb.base/local-static.exp: Also test with
class::method::variable wholly quoted.
* gdb.cp/m-static.exp (class::method::variable): Remove test.
This commit makes "print S::method()::static_var" actually find the
debug symbol for static_var. Currently, you get:
(gdb) print S::method()::static_var
A syntax error in expression, near `'.
Quoting the whole string would seemingly work before the previous
patch that made GDB stop assuming int for no-debug-info variables:
(gdb) p 'S::method()::static_var'
$1 = 1
... except that's incorrect output, because:
(gdb) ptype 'S::method()::static_var'
type = <data variable, no debug info>
The way to make it work correctly currently is by quoting the
function/method part, like this:
(gdb) print 'S::method()'::static_var
$1 = {i1 = 1, i2 = 2, i3 = 3}
(gdb) ptype 'S::method()'::static_var
type = struct aggregate {
int i1;
int i2;
int i3;
}
At least after the "stop assuming int" patch, this is what we
now get:
(gdb) p 'S::method()::static_var'
'S::method()::static_var' has unknown type; cast it to its declared type
(gdb) p (struct aggregate) 'S::method()::static_var'
$1 = {i1 = 1, i2 = 2, i3 = 3}
However, IMO, users shouldn't really have to care about any of this.
GDB should Just Work, without quoting, IMO.
So here's a patch that implements support for that in the C++ parser.
With this patch, you now get:
(gdb) p S::method()::S_M_s_var_aggregate
$1 = {i1 = 1, i2 = 2, i3 = 3}
(gdb) ptype S::method()::S_M_s_var_aggregate
type = struct aggregate {
int i1;
int i2;
int i3;
}
gdb/ChangeLog:
2017-09-04 Pedro Alves <palves@redhat.com>
(%type <voidval>): Add function_method.
* c-exp.y (exp): New production for calls with no arguments.
(function_method, function_method_void_or_typelist): New
productions.
(exp): New production for "method()::static_var".
* eval.c (evaluate_subexp_standard): Handle OP_FUNC_STATIC_VAR.
* expprint.c (print_subexp_standard, dump_subexp_body_standard):
Handle OP_FUNC_STATIC_VAR.
* parse.c (operator_length_standard):
Handle OP_FUNC_STATIC_VAR.
* std-operator.def (OP_FUNC_STATIC_VAR): New.
gdb/testsuite/ChangeLog:
2017-09-04 Pedro Alves <palves@redhat.com>
* gdb.base/local-static.c: New.
* gdb.base/local-static.cc: New.
* gdb.base/local-static.exp: New.
Since minsym references now go via OP_VAR_MSYM_VALUE, UNOP_MEMVAL_TLS
is no longer used anywhere.
gdb/ChangeLog:
2017-09-04 Pedro Alves <palves@redhat.com>
* eval.c (evaluate_subexp_standard): Remove UNOP_MEMVAL_TLS
handling.
* expprint.c (print_subexp_standard, dump_subexp_body_standard):
Ditto.
* parse.c (operator_length_standard, operator_check_standard):
Ditto.
* std-operator.def (UNOP_MEMVAL_TLS): Delete.
The previous patch left GDB with an inconsistency. While with normal
expression evaluation the "unknown return type" error shows the name
of the function that misses debug info:
(gdb) p getenv ("PATH")
'getenv' has unknown return type; cast the call to its declared return type
^^^^^^
which can by handy in more complicated expressions, "ptype" does not:
(gdb) ptype getenv ("PATH")
function has unknown return type; cast the call to its declared return type
^^^^^^^^
This commit is a step toward fixing it.
The problem is that while evaluating the expression above, we have no
reference to the minimal symbol where we could extract the name from.
This is because the resulting expression tree has no reference to the
minsym at all. During parsing, the type and address of the minsym are
extracted and an UNOP_MEMVAL / UNOP_MEMVAL_TLS operator is generated
(see write_exp_elt_msym). With "set debug expression", here's what
you see:
0 OP_FUNCALL Number of args: 0
3 UNOP_MEMVAL Type @0x565334a51930 (<text variable, no debug info>)
6 OP_LONG Type @0x565334a51c60 (__CORE_ADDR), value 140737345035648 (0x7ffff7751d80)
The "print" case finds the function name, because
call_function_by_hand looks up the function by address again.
However, for "ptype", we don't reach that code, because obviously we
don't really call the function.
Unlike minsym references, references to variables with debug info have
a pointer to the variable's symbol in the expression tree, with
OP_VAR_VALUE:
(gdb) ptype main()
...
0 OP_FUNCALL Number of args: 0
3 OP_VAR_VALUE Block @0x0, symbol @0x559bbbd9b358 (main(int, char**))
...
so I don't see why do minsyms need to be different. So to prepare for
fixing the missing function name issue, this commit adds a new
OP_VAR_MSYM_VALUE operator that mimics OP_VAR_VALUE, except that it's
for minsyms instead of debug symbols. For infcalls, we now get
expressions like these:
0 OP_FUNCALL Number of args: 0
3 OP_VAR_MSYM_VALUE Objfile @0x1e41bf0, msymbol @0x7fffe599b000 (getenv)
In the following patch, we'll make OP_FUNCALL extract the function
name from the symbol stored in OP_VAR_VALUE/OP_VAR_MSYM_VALUE.
OP_VAR_MSYM_VALUE will be used more in a later patch in the series
too.
gdb/ChangeLog:
2017-09-04 Pedro Alves <palves@redhat.com>
* ada-lang.c (resolve_subexp): Handle OP_VAR_MSYM_VALUE.
* ax-gdb.c (gen_msym_var_ref): New function.
(gen_expr): Handle OP_VAR_MSYM_VALUE.
* eval.c (evaluate_var_msym_value): New function.
* eval.c (evaluate_subexp_standard): Handle OP_VAR_MSYM_VALUE.
<OP_FUNCALL>: Extract function name from symbol/minsym and pass it
to call_function_by_hand.
* expprint.c (print_subexp_standard, dump_subexp_body_standard):
Handle OP_VAR_MSYM_VALUE.
(union exp_element) <msymbol>: New field.
* minsyms.h (struct type): Forward declare.
(find_minsym_type_and_address): Declare.
* parse.c (write_exp_elt_msym): New function.
(write_exp_msymbol): Delete, refactored as ...
(find_minsym_type_and_address): ... this new function.
(write_exp_msymbol): Reimplement using OP_VAR_MSYM_VALUE.
(operator_length_standard, operator_check_standard): Handle
OP_VAR_MSYM_VALUE.
* std-operator.def (OP_VAR_MSYM_VALUE): New.
This applies the second part of GDB's End of Year Procedure, which
updates the copyright year range in all of GDB's files.
gdb/ChangeLog:
Update copyright year range in all GDB files.
TERNOP_SLICE was added for language Chill, but it is used for Ada and D later.
Since language Chill was removed from GDB, TERNOP_SLICE is only used for
Ada and D. This patch is to update its comments.
gdb:
2014-07-20 Yao Qi <yao@codesourcery.com>
* std-operator.def: Update comments to TERNOP_SLICE.
BINOP_RANGE was added by the following commit for chill language.
commit badefd2800
Author: Per Bothner <per@bothner.com>
Date: Wed Nov 29 22:59:31 1995 +0000
* expression.h (enum exp_opcode): Add BINOP_RANGE.
* expprint.c (dump_expression): Support BINOP_RANGE.
* eval.c (evaluate_subexp_standard): Handle BINOP_RANGE (as error).
(case MULTI_SUBSCRIPT): Fix broken f77 value->int ad hoc conversion.
* ch-lang.c (chill_op_print_tab): Support BINOP_RANGE.
(evaluate_subexp_chill): Error on BINOP_COMMA.
Chill language is no longer supported, so we can remove BINOP_RANGE too.
This patch is to remove BINOP_RANGE.
gdb:
2014-07-20 Yao Qi <yao@codesourcery.com>
* std-operator.def: Remove BINOP_RANGE.
* breakpoint.c (watchpoint_exp_is_const): Update.
* expprint.c (dump_subexp_body_standard): Likewise.
* eval.c (init_array_element): Remove dead code.
(evaluate_subexp_standard): Likewise.
Chill language support was removed several years ago, and BINOP_IN
isn't used for Pascal. This patch is to remove BINOP_IN.
gdb:
2014-07-20 Yao Qi <yao@codesourcery.com>
* std-operator.def: Remove BINOP_IN.
* breakpoint.c (watchpoint_exp_is_const): Update.
* eval.c (evaluate_subexp_standard): Likewise.
* expprint.c (dump_subexp_body_standard): Likewise.
Two modifications:
1. The addition of 2013 to the copyright year range for every file;
2. The use of a single year range, instead of potentially multiple
year ranges, as approved by the FSF.
