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3693fdb3c8
Trying to print a function local static variable of a const-qualified
method still doesn't work after the previous fixes:
(gdb) p 'S::method() const'::static_var
$1 = {i1 = 1, i2 = 2, i3 = 3}
(gdb) p S::method() const::static_var
No symbol "static_var" in specified context.
The reason is that the expression parser/evaluator loses the "const",
and the above unquoted case is just like trying to print a variable of
the non-const overload, if it exists, even. As if the above unquoted
case had been written as:
(gdb) p S::method()::static_var
No symbol "static_var" in specified context.
We can see the problem without static vars in the picture. With:
struct S
{
void method ();
void method () const;
};
Compare:
(gdb) print 'S::method(void) const'
$1 = {void (const S * const)} 0x400606 <S::method() const>
(gdb) print S::method(void) const
$2 = {void (S * const)} 0x4005d8 <S::method()> # wrong method!
That's what we need to fix. If we fix that, the function local static
case starts working.
The grammar production for function/method types is this one:
exp: exp '(' parameter_typelist ')' const_or_volatile
This results in a TYPE_INSTANCE expression evaluator operator. For
the example above, we get something like this ("set debug expression 1"):
...
0 TYPE_INSTANCE 1 TypeInstance: Type @0x560fda958be0 (void)
5 OP_SCOPE Type @0x560fdaa544d8 (S) Field name: `method'
...
While evaluating TYPE_INSTANCE, we end up in
value_struct_elt_for_reference, trying to find the method named
"method" that has the prototype recorded in TYPE_INSTANCE. In this
case, TYPE_INSTANCE says that we're looking for a method that has
"(void)" as parameters (that's what "1 TypeInstance: Type
@0x560fda958be0 (void)" above means. The trouble is that nowhere in
this mechanism do we communicate to value_struct_elt_for_reference
that we're looking for the _const_ overload.
value_struct_elt_for_reference only compared parameters, and the
non-const "method()" overload has matching parameters, so it's
considered the right match...
Conveniently, the "const_or_volatile" production in the grammar
already records "const" and "volatile" info in the type stack. The
type stack is not used in this code path, but we can borrow the
information. The patch converts the info in the type stack to an
"instance flags" enum, and adds that as another element in
TYPE_INSTANCE operators. This type instance flags is then applied to
the temporary type that is passed to value_struct_elt_for_reference
for matching.
The other side of the problem is that methods in the debug info aren't
marked const/volatile, so with that in place, the matching never finds
const/volatile-qualified methods.
The problem is that in the DWARF, there's no indication at all whether
a method is const/volatile qualified... For example (c++filt applied
to the linkage name for convenience):
<2><d3>: Abbrev Number: 6 (DW_TAG_subprogram)
<d4> DW_AT_external : 1
<d4> DW_AT_name : (indirect string, offset: 0x3df): method
<d8> DW_AT_decl_file : 1
<d9> DW_AT_decl_line : 58
<da> DW_AT_linkage_name: (indirect string, offset: 0x5b2): S::method() const
<de> DW_AT_declaration : 1
<de> DW_AT_object_pointer: <0xe6>
<e2> DW_AT_sibling : <0xec>
I see the same with both GCC and Clang. The patch works around this
by extracting the cv qualification from the "const" and "volatile" in
the demangled name. This will need further tweaking for "&" and
"const &" overloads, but we don't support them in the parser yet,
anyway.
The TYPE_CONST changes were necessary otherwise the comparisons in valops.c:
if (TYPE_CONST (intype) != TYPE_FN_FIELD_CONST (f, j))
continue;
would fail, because when both TYPE_CONST() TYPE_FN_FIELD_CONST() were
true, their values were different.
BTW, I'm recording the const/volatile-ness of methods in the
TYPE_FN_FIELD info because #1 - I'm not sure it's kosher to change the
method's type directly (vs having to call make_cv_type to create a new
type), and #2 it's what stabsread.c does:
...
case 'A': /* Normal functions. */
new_sublist->fn_field.is_const = 0;
new_sublist->fn_field.is_volatile = 0;
(*pp)++;
break;
case 'B': /* `const' member functions. */
new_sublist->fn_field.is_const = 1;
new_sublist->fn_field.is_volatile = 0;
...
After all this, this finally all works:
print S::method(void) const
$1 = {void (const S * const)} 0x400606 <S::method() const>
(gdb) p S::method() const::static_var
$2 = {i1 = 1, i2 = 2, i3 = 3}
gdb/ChangeLog:
2017-09-04 Pedro Alves <palves@redhat.com>
* c-exp.y (function_method, function_method_void): Add current
instance flags to TYPE_INSTANCE.
* dwarf2read.c (check_modifier): New.
(compute_delayed_physnames): Assert that only C++ adds delayed
physnames. Mark fn_fields as const/volatile depending on
physname.
* eval.c (make_params): New type_instance_flags parameter. Use
it as the new type's instance flags.
(evaluate_subexp_standard) <TYPE_INSTANCE>: Extract the instance
flags element and pass it to make_params.
* expprint.c (print_subexp_standard) <TYPE_INSTANCE>: Handle
instance flags element.
(dump_subexp_body_standard) <TYPE_INSTANCE>: Likewise.
* gdbtypes.h: Include "enum-flags.h".
(type_instance_flags): New enum-flags type.
(TYPE_CONST, TYPE_VOLATILE, TYPE_RESTRICT, TYPE_ATOMIC)
(TYPE_CODE_SPACE, TYPE_DATA_SPACE): Return boolean.
* parse.c (operator_length_standard) <TYPE_INSTANCE>: Adjust.
(follow_type_instance_flags): New function.
(operator_check_standard) <TYPE_INSTANCE>: Adjust.
* parser-defs.h (follow_type_instance_flags): Declare.
* valops.c (value_struct_elt_for_reference): const/volatile must
match too.
gdb/testsuite/ChangeLog:
2017-09-04 Pedro Alves <palves@redhat.com>
* gdb.base/func-static.c (S::method const, S::method volatile)
(S::method volatile const): New methods.
(c_s, v_s, cv_s): New instances.
(main): Call method() on them.
* gdb.base/func-static.exp (syntax_re, cannot_resolve_re): New variables.
(cannot_resolve): New procedure.
(cxx_scopes_list): Test cv methods. Add print-scope-quote and
print-quote-unquoted columns.
(do_test): Test printing each scope too.
401 lines
12 KiB
C
401 lines
12 KiB
C
/* Parser definitions for GDB.
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Copyright (C) 1986-2017 Free Software Foundation, Inc.
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Modified from expread.y by the Department of Computer Science at the
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State University of New York at Buffalo.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#if !defined (PARSER_DEFS_H)
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#define PARSER_DEFS_H 1
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#include "doublest.h"
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#include "vec.h"
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#include "expression.h"
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struct block;
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struct language_defn;
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struct internalvar;
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extern int parser_debug;
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#define parse_gdbarch(ps) ((ps)->expout->gdbarch)
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#define parse_language(ps) ((ps)->expout->language_defn)
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struct parser_state
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{
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/* The expression related to this parser state. */
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struct expression *expout;
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/* The size of the expression above. */
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size_t expout_size;
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/* The number of elements already in the expression. This is used
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to know where to put new elements. */
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size_t expout_ptr;
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};
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/* If this is nonzero, this block is used as the lexical context
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for symbol names. */
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extern const struct block *expression_context_block;
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/* If expression_context_block is non-zero, then this is the PC within
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the block that we want to evaluate expressions at. When debugging
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C or C++ code, we use this to find the exact line we're at, and
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then look up the macro definitions active at that point. */
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extern CORE_ADDR expression_context_pc;
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/* The innermost context required by the stack and register variables
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we've encountered so far. */
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extern const struct block *innermost_block;
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/* Number of arguments seen so far in innermost function call. */
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extern int arglist_len;
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/* A string token, either a char-string or bit-string. Char-strings are
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used, for example, for the names of symbols. */
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struct stoken
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{
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/* Pointer to first byte of char-string or first bit of bit-string. */
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const char *ptr;
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/* Length of string in bytes for char-string or bits for bit-string. */
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int length;
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};
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struct typed_stoken
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{
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/* A language-specific type field. */
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int type;
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/* Pointer to first byte of char-string or first bit of bit-string. */
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char *ptr;
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/* Length of string in bytes for char-string or bits for bit-string. */
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int length;
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};
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struct stoken_vector
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{
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int len;
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struct typed_stoken *tokens;
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};
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struct ttype
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{
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struct stoken stoken;
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struct type *type;
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};
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struct symtoken
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{
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struct stoken stoken;
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struct block_symbol sym;
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int is_a_field_of_this;
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};
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struct objc_class_str
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{
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struct stoken stoken;
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struct type *type;
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int theclass;
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};
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typedef struct type *type_ptr;
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DEF_VEC_P (type_ptr);
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/* For parsing of complicated types.
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An array should be preceded in the list by the size of the array. */
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enum type_pieces
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{
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tp_end = -1,
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tp_pointer,
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tp_reference,
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tp_rvalue_reference,
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tp_array,
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tp_function,
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tp_function_with_arguments,
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tp_const,
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tp_volatile,
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tp_space_identifier,
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tp_type_stack
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};
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/* The stack can contain either an enum type_pieces or an int. */
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union type_stack_elt
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{
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enum type_pieces piece;
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int int_val;
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struct type_stack *stack_val;
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VEC (type_ptr) *typelist_val;
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};
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/* The type stack is an instance of this structure. */
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struct type_stack
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{
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/* Elements on the stack. */
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union type_stack_elt *elements;
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/* Current stack depth. */
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int depth;
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/* Allocated size of stack. */
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int size;
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};
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/* Helper function to initialize the expout, expout_size, expout_ptr
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trio inside PS before it is used to store expression elements created
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during the parsing of an expression. INITIAL_SIZE is the initial size of
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the expout array. LANG is the language used to parse the expression.
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And GDBARCH is the gdbarch to use during parsing. */
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extern void initialize_expout (struct parser_state *ps,
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size_t initial_size,
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const struct language_defn *lang,
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struct gdbarch *gdbarch);
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/* Helper function that reallocates the EXPOUT inside PS in order to
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eliminate any unused space. It is generally used when the expression
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has just been parsed and created. */
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extern void reallocate_expout (struct parser_state *ps);
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/* Reverse an expression from suffix form (in which it is constructed)
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to prefix form (in which we can conveniently print or execute it).
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Ordinarily this always returns -1. However, if EXPOUT_LAST_STRUCT
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is not -1 (i.e., we are trying to complete a field name), it will
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return the index of the subexpression which is the left-hand-side
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of the struct operation at EXPOUT_LAST_STRUCT. */
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extern int prefixify_expression (struct expression *expr);
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extern void write_exp_elt_opcode (struct parser_state *, enum exp_opcode);
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extern void write_exp_elt_sym (struct parser_state *, struct symbol *);
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extern void write_exp_elt_longcst (struct parser_state *, LONGEST);
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extern void write_exp_elt_dblcst (struct parser_state *, DOUBLEST);
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extern void write_exp_elt_decfloatcst (struct parser_state *, gdb_byte *);
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extern void write_exp_elt_type (struct parser_state *, struct type *);
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extern void write_exp_elt_intern (struct parser_state *, struct internalvar *);
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extern void write_exp_string (struct parser_state *, struct stoken);
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void write_exp_string_vector (struct parser_state *, int type,
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struct stoken_vector *vec);
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extern void write_exp_bitstring (struct parser_state *, struct stoken);
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extern void write_exp_elt_block (struct parser_state *, const struct block *);
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extern void write_exp_elt_objfile (struct parser_state *,
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struct objfile *objfile);
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extern void write_exp_msymbol (struct parser_state *,
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struct bound_minimal_symbol);
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extern void write_dollar_variable (struct parser_state *, struct stoken str);
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extern void mark_struct_expression (struct parser_state *);
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extern const char *find_template_name_end (const char *);
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extern void start_arglist (void);
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extern int end_arglist (void);
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extern char *copy_name (struct stoken);
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extern void insert_type (enum type_pieces);
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extern void push_type (enum type_pieces);
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extern void push_type_int (int);
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extern void insert_type_address_space (struct parser_state *, char *);
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extern enum type_pieces pop_type (void);
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extern int pop_type_int (void);
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extern struct type_stack *get_type_stack (void);
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extern struct type_stack *append_type_stack (struct type_stack *to,
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struct type_stack *from);
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extern void push_type_stack (struct type_stack *stack);
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extern void type_stack_cleanup (void *arg);
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extern void push_typelist (VEC (type_ptr) *typelist);
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extern int dump_subexp (struct expression *, struct ui_file *, int);
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extern int dump_subexp_body_standard (struct expression *,
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struct ui_file *, int);
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extern void operator_length (const struct expression *, int, int *, int *);
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extern void operator_length_standard (const struct expression *, int, int *,
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int *);
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extern int operator_check_standard (struct expression *exp, int pos,
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int (*objfile_func)
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(struct objfile *objfile, void *data),
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void *data);
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extern const char *op_name_standard (enum exp_opcode);
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extern struct type *follow_types (struct type *);
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extern type_instance_flags follow_type_instance_flags ();
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extern void null_post_parser (struct expression **, int);
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extern int parse_float (const char *p, int len, DOUBLEST *d,
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const char **suffix);
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extern int parse_c_float (struct gdbarch *gdbarch, const char *p, int len,
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DOUBLEST *d, struct type **t);
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/* During parsing of a C expression, the pointer to the next character
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is in this variable. */
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extern const char *lexptr;
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/* After a token has been recognized, this variable points to it.
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Currently used only for error reporting. */
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extern const char *prev_lexptr;
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/* Current depth in parentheses within the expression. */
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extern int paren_depth;
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/* Nonzero means stop parsing on first comma (if not within parentheses). */
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extern int comma_terminates;
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/* These codes indicate operator precedences for expression printing,
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least tightly binding first. */
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/* Adding 1 to a precedence value is done for binary operators,
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on the operand which is more tightly bound, so that operators
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of equal precedence within that operand will get parentheses. */
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/* PREC_HYPER and PREC_ABOVE_COMMA are not the precedence of any operator;
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they are used as the "surrounding precedence" to force
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various kinds of things to be parenthesized. */
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enum precedence
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{
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PREC_NULL, PREC_COMMA, PREC_ABOVE_COMMA, PREC_ASSIGN, PREC_LOGICAL_OR,
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PREC_LOGICAL_AND, PREC_BITWISE_IOR, PREC_BITWISE_AND, PREC_BITWISE_XOR,
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PREC_EQUAL, PREC_ORDER, PREC_SHIFT, PREC_ADD, PREC_MUL, PREC_REPEAT,
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PREC_HYPER, PREC_PREFIX, PREC_SUFFIX, PREC_BUILTIN_FUNCTION
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};
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/* Table mapping opcodes into strings for printing operators
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and precedences of the operators. */
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struct op_print
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{
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const char *string;
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enum exp_opcode opcode;
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/* Precedence of operator. These values are used only by comparisons. */
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enum precedence precedence;
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/* For a binary operator: 1 iff right associate.
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For a unary operator: 1 iff postfix. */
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int right_assoc;
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};
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/* Information needed to print, prefixify, and evaluate expressions for
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a given language. */
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struct exp_descriptor
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{
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/* Print subexpression. */
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void (*print_subexp) (struct expression *, int *, struct ui_file *,
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enum precedence);
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/* Returns number of exp_elements needed to represent an operator and
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the number of subexpressions it takes. */
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void (*operator_length) (const struct expression*, int, int*, int *);
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/* Call OBJFILE_FUNC for any objfile found being referenced by the
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single operator of EXP at position POS. Operator parameters are
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located at positive (POS + number) offsets in EXP. OBJFILE_FUNC
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should never be called with NULL OBJFILE. OBJFILE_FUNC should
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get passed an arbitrary caller supplied DATA pointer. If it
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returns non-zero value then (any other) non-zero value should be
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immediately returned to the caller. Otherwise zero should be
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returned. */
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int (*operator_check) (struct expression *exp, int pos,
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int (*objfile_func) (struct objfile *objfile,
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void *data),
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void *data);
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/* Name of this operator for dumping purposes.
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The returned value should never be NULL, even if EXP_OPCODE is
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an unknown opcode (a string containing an image of the numeric
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value of the opcode can be returned, for instance). */
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const char *(*op_name) (enum exp_opcode);
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/* Dump the rest of this (prefix) expression after the operator
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itself has been printed. See dump_subexp_body_standard in
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(expprint.c). */
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int (*dump_subexp_body) (struct expression *, struct ui_file *, int);
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/* Evaluate an expression. */
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struct value *(*evaluate_exp) (struct type *, struct expression *,
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int *, enum noside);
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};
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/* Default descriptor containing standard definitions of all
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elements. */
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extern const struct exp_descriptor exp_descriptor_standard;
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/* Functions used by language-specific extended operators to (recursively)
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print/dump subexpressions. */
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extern void print_subexp (struct expression *, int *, struct ui_file *,
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enum precedence);
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extern void print_subexp_standard (struct expression *, int *,
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struct ui_file *, enum precedence);
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/* Function used to avoid direct calls to fprintf
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in the code generated by the bison parser. */
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extern void parser_fprintf (FILE *, const char *, ...) ATTRIBUTE_PRINTF (2, 3);
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extern int exp_uses_objfile (struct expression *exp, struct objfile *objfile);
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extern void mark_completion_tag (enum type_code, const char *ptr,
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int length);
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/* Reallocate the `expout' pointer inside PS so that it can accommodate
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at least LENELT expression elements. This function does nothing if
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there is enough room for the elements. */
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extern void increase_expout_size (struct parser_state *ps, size_t lenelt);
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#endif /* PARSER_DEFS_H */
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