309 lines
9.4 KiB
C++
309 lines
9.4 KiB
C++
/* Definitions for expressions stored in reversed prefix form, for GDB.
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Copyright (C) 1986-2022 Free Software Foundation, Inc.
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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 (EXPRESSION_H)
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#define EXPRESSION_H 1
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#include "gdbtypes.h"
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/* While parsing expressions we need to track the innermost lexical block
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that we encounter. In some situations we need to track the innermost
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block just for symbols, and in other situations we want to track the
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innermost block for symbols and registers. These flags are used by the
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innermost block tracker to control which blocks we consider for the
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innermost block. These flags can be combined together as needed. */
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enum innermost_block_tracker_type
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{
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/* Track the innermost block for symbols within an expression. */
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INNERMOST_BLOCK_FOR_SYMBOLS = (1 << 0),
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/* Track the innermost block for registers within an expression. */
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INNERMOST_BLOCK_FOR_REGISTERS = (1 << 1)
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};
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DEF_ENUM_FLAGS_TYPE (enum innermost_block_tracker_type,
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innermost_block_tracker_types);
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enum exp_opcode : uint8_t
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{
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#define OP(name) name ,
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#include "std-operator.def"
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#undef OP
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};
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/* Values of NOSIDE argument to eval_subexp. */
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enum noside
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{
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EVAL_NORMAL,
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EVAL_AVOID_SIDE_EFFECTS /* Don't modify any variables or
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call any functions. The value
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returned will have the correct
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type, and will have an
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approximately correct lvalue
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type (inaccuracy: anything that is
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listed as being in a register in
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the function in which it was
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declared will be lval_register).
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Ideally this would not even read
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target memory, but currently it
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does in many situations. */
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};
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struct expression;
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struct agent_expr;
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struct axs_value;
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struct type;
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struct ui_file;
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namespace expr
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{
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class operation;
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typedef std::unique_ptr<operation> operation_up;
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/* Base class for an operation. An operation is a single component of
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an expression. */
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class operation
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{
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protected:
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operation () = default;
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DISABLE_COPY_AND_ASSIGN (operation);
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public:
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virtual ~operation () = default;
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/* Evaluate this operation. */
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virtual value *evaluate (struct type *expect_type,
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struct expression *exp,
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enum noside noside) = 0;
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/* Evaluate this operation in a context where C-like coercion is
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needed. */
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virtual value *evaluate_with_coercion (struct expression *exp,
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enum noside noside)
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{
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return evaluate (nullptr, exp, noside);
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}
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/* Evaluate this expression in the context of a cast to
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EXPECT_TYPE. */
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virtual value *evaluate_for_cast (struct type *expect_type,
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struct expression *exp,
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enum noside noside);
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/* Evaluate this expression in the context of a sizeof
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operation. */
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virtual value *evaluate_for_sizeof (struct expression *exp,
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enum noside noside);
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/* Evaluate this expression in the context of an address-of
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operation. Must return the address. */
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virtual value *evaluate_for_address (struct expression *exp,
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enum noside noside);
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/* Evaluate a function call, with this object as the callee.
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EXPECT_TYPE, EXP, and NOSIDE have the same meaning as in
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'evaluate'. ARGS holds the operations that should be evaluated
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to get the arguments to the call. */
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virtual value *evaluate_funcall (struct type *expect_type,
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struct expression *exp,
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enum noside noside,
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const std::vector<operation_up> &args)
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{
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/* Defer to the helper overload. */
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return evaluate_funcall (expect_type, exp, noside, nullptr, args);
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}
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/* True if this is a constant expression. */
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virtual bool constant_p () const
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{ return false; }
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/* Return true if this operation uses OBJFILE (and will become
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dangling when OBJFILE is unloaded), otherwise return false.
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OBJFILE must not be a separate debug info file. */
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virtual bool uses_objfile (struct objfile *objfile) const
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{ return false; }
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/* Generate agent expression bytecodes for this operation. */
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void generate_ax (struct expression *exp, struct agent_expr *ax,
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struct axs_value *value,
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struct type *cast_type = nullptr);
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/* Return the opcode that is implemented by this operation. */
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virtual enum exp_opcode opcode () const = 0;
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/* Print this operation to STREAM. */
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virtual void dump (struct ui_file *stream, int depth) const = 0;
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/* Call to indicate that this is the outermost operation in the
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expression. This should almost never be overridden. */
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virtual void set_outermost () { }
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protected:
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/* A helper overload that wraps evaluate_subexp_do_call. */
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value *evaluate_funcall (struct type *expect_type,
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struct expression *exp,
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enum noside noside,
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const char *function_name,
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const std::vector<operation_up> &args);
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/* Called by generate_ax to do the work for this particular
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operation. */
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virtual void do_generate_ax (struct expression *exp,
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struct agent_expr *ax,
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struct axs_value *value,
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struct type *cast_type)
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{
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error (_("Cannot translate to agent expression"));
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}
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};
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/* A helper function for creating an operation_up, given a type. */
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template<typename T, typename... Arg>
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operation_up
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make_operation (Arg... args)
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{
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return operation_up (new T (std::forward<Arg> (args)...));
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}
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}
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struct expression
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{
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expression (const struct language_defn *lang, struct gdbarch *arch)
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: language_defn (lang),
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gdbarch (arch)
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{
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}
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DISABLE_COPY_AND_ASSIGN (expression);
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/* Return the opcode for the outermost sub-expression of this
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expression. */
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enum exp_opcode first_opcode () const
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{
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return op->opcode ();
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}
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/* Evaluate the expression. EXPECT_TYPE is the context type of the
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expression; normally this should be nullptr. NOSIDE controls how
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evaluation is performed. */
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struct value *evaluate (struct type *expect_type, enum noside noside);
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/* Language it was entered in. */
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const struct language_defn *language_defn;
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/* Architecture it was parsed in. */
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struct gdbarch *gdbarch;
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expr::operation_up op;
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};
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typedef std::unique_ptr<expression> expression_up;
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/* From parse.c */
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class innermost_block_tracker;
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extern expression_up parse_expression (const char *,
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innermost_block_tracker * = nullptr,
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bool void_context_p = false);
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extern expression_up parse_expression_with_language (const char *string,
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enum language lang);
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class completion_tracker;
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/* Base class for expression completion. An instance of this
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represents a completion request from the parser. */
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struct expr_completion_base
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{
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/* Perform this object's completion. EXP is the expression in which
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the completion occurs. TRACKER is the tracker to update with the
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results. Return true if completion was possible (even if no
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completions were found), false to fall back to ordinary
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expression completion (i.e., symbol names). */
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virtual bool complete (struct expression *exp,
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completion_tracker &tracker) = 0;
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virtual ~expr_completion_base () = default;
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};
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extern expression_up parse_expression_for_completion
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(const char *, std::unique_ptr<expr_completion_base> *completer);
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class innermost_block_tracker;
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extern expression_up parse_exp_1 (const char **, CORE_ADDR pc,
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const struct block *, int,
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innermost_block_tracker * = nullptr);
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/* From eval.c */
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/* Evaluate a function call. The function to be called is in CALLEE and
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the arguments passed to the function are in ARGVEC.
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FUNCTION_NAME is the name of the function, if known.
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DEFAULT_RETURN_TYPE is used as the function's return type if the return
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type is unknown. */
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extern struct value *evaluate_subexp_do_call (expression *exp,
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enum noside noside,
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value *callee,
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gdb::array_view<value *> argvec,
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const char *function_name,
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type *default_return_type);
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/* From expprint.c */
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extern const char *op_name (enum exp_opcode opcode);
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extern void dump_prefix_expression (struct expression *, struct ui_file *);
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/* In an OP_RANGE expression, either bound could be empty, indicating
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that its value is by default that of the corresponding bound of the
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array or string. Also, the upper end of the range can be exclusive
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or inclusive. So we have six sorts of subrange. This enumeration
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type is to identify this. */
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enum range_flag : unsigned
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{
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/* This is a standard range. Both the lower and upper bounds are
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defined, and the bounds are inclusive. */
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RANGE_STANDARD = 0,
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/* The low bound was not given. */
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RANGE_LOW_BOUND_DEFAULT = 1 << 0,
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/* The high bound was not given. */
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RANGE_HIGH_BOUND_DEFAULT = 1 << 1,
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/* The high bound of this range is exclusive. */
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RANGE_HIGH_BOUND_EXCLUSIVE = 1 << 2,
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/* The range has a stride. */
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RANGE_HAS_STRIDE = 1 << 3,
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};
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DEF_ENUM_FLAGS_TYPE (enum range_flag, range_flags);
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#endif /* !defined (EXPRESSION_H) */
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