/* Definitions for expressions stored in reversed prefix form, for GDB.
- Copyright (C) 1986-2020 Free Software Foundation, Inc.
+ Copyright (C) 1986-2022 Free Software Foundation, Inc.
This file is part of GDB.
DEF_ENUM_FLAGS_TYPE (enum innermost_block_tracker_type,
innermost_block_tracker_types);
-/* Definitions for saved C expressions. */
-
-/* An expression is represented as a vector of union exp_element's.
- Each exp_element is an opcode, except that some opcodes cause
- the following exp_element to be treated as a long or double constant
- or as a variable. The opcodes are obeyed, using a stack for temporaries.
- The value is left on the temporary stack at the end. */
-
-/* When it is necessary to include a string,
- it can occupy as many exp_elements as it needs.
- We find the length of the string using strlen,
- divide to find out how many exp_elements are used up,
- and skip that many. Strings, like numbers, are indicated
- by the preceding opcode. */
-
enum exp_opcode : uint8_t
{
#define OP(name) name ,
#include "std-operator.def"
#undef OP
-
- /* Existing only to swallow the last comma (',') from last .inc file. */
- OP_UNUSED_LAST
};
-union exp_element
+/* Values of NOSIDE argument to eval_subexp. */
+
+enum noside
{
- enum exp_opcode opcode;
- struct symbol *symbol;
- struct minimal_symbol *msymbol;
- LONGEST longconst;
- gdb_byte floatconst[16];
- /* Really sizeof (union exp_element) characters (or less for the last
- element of a string). */
- char string;
- struct type *type;
- struct internalvar *internalvar;
- const struct block *block;
- struct objfile *objfile;
+ EVAL_NORMAL,
+ EVAL_AVOID_SIDE_EFFECTS /* Don't modify any variables or
+ call any functions. The value
+ returned will have the correct
+ type, and will have an
+ approximately correct lvalue
+ type (inaccuracy: anything that is
+ listed as being in a register in
+ the function in which it was
+ declared will be lval_register).
+ Ideally this would not even read
+ target memory, but currently it
+ does in many situations. */
};
+struct expression;
+struct agent_expr;
+struct axs_value;
+struct type;
+struct ui_file;
+
+namespace expr
+{
+
+class operation;
+typedef std::unique_ptr<operation> operation_up;
+
+/* Base class for an operation. An operation is a single component of
+ an expression. */
+
+class operation
+{
+protected:
+
+ operation () = default;
+ DISABLE_COPY_AND_ASSIGN (operation);
+
+public:
+
+ virtual ~operation () = default;
+
+ /* Evaluate this operation. */
+ virtual value *evaluate (struct type *expect_type,
+ struct expression *exp,
+ enum noside noside) = 0;
+
+ /* Evaluate this operation in a context where C-like coercion is
+ needed. */
+ virtual value *evaluate_with_coercion (struct expression *exp,
+ enum noside noside)
+ {
+ return evaluate (nullptr, exp, noside);
+ }
+
+ /* Evaluate this expression in the context of a cast to
+ EXPECT_TYPE. */
+ virtual value *evaluate_for_cast (struct type *expect_type,
+ struct expression *exp,
+ enum noside noside);
+
+ /* Evaluate this expression in the context of a sizeof
+ operation. */
+ virtual value *evaluate_for_sizeof (struct expression *exp,
+ enum noside noside);
+
+ /* Evaluate this expression in the context of an address-of
+ operation. Must return the address. */
+ virtual value *evaluate_for_address (struct expression *exp,
+ enum noside noside);
+
+ /* Evaluate a function call, with this object as the callee.
+ EXPECT_TYPE, EXP, and NOSIDE have the same meaning as in
+ 'evaluate'. ARGS holds the operations that should be evaluated
+ to get the arguments to the call. */
+ virtual value *evaluate_funcall (struct type *expect_type,
+ struct expression *exp,
+ enum noside noside,
+ const std::vector<operation_up> &args)
+ {
+ /* Defer to the helper overload. */
+ return evaluate_funcall (expect_type, exp, noside, nullptr, args);
+ }
+
+ /* True if this is a constant expression. */
+ virtual bool constant_p () const
+ { return false; }
+
+ /* Return true if this operation uses OBJFILE (and will become
+ dangling when OBJFILE is unloaded), otherwise return false.
+ OBJFILE must not be a separate debug info file. */
+ virtual bool uses_objfile (struct objfile *objfile) const
+ { return false; }
+
+ /* Generate agent expression bytecodes for this operation. */
+ void generate_ax (struct expression *exp, struct agent_expr *ax,
+ struct axs_value *value,
+ struct type *cast_type = nullptr);
+
+ /* Return the opcode that is implemented by this operation. */
+ virtual enum exp_opcode opcode () const = 0;
+
+ /* Print this operation to STREAM. */
+ virtual void dump (struct ui_file *stream, int depth) const = 0;
+
+ /* Call to indicate that this is the outermost operation in the
+ expression. This should almost never be overridden. */
+ virtual void set_outermost () { }
+
+protected:
+
+ /* A helper overload that wraps evaluate_subexp_do_call. */
+ value *evaluate_funcall (struct type *expect_type,
+ struct expression *exp,
+ enum noside noside,
+ const char *function_name,
+ const std::vector<operation_up> &args);
+
+ /* Called by generate_ax to do the work for this particular
+ operation. */
+ virtual void do_generate_ax (struct expression *exp,
+ struct agent_expr *ax,
+ struct axs_value *value,
+ struct type *cast_type)
+ {
+ error (_("Cannot translate to agent expression"));
+ }
+};
+
+/* A helper function for creating an operation_up, given a type. */
+template<typename T, typename... Arg>
+operation_up
+make_operation (Arg... args)
+{
+ return operation_up (new T (std::forward<Arg> (args)...));
+}
+
+}
+
struct expression
{
- expression (const struct language_defn *, struct gdbarch *, size_t);
- ~expression ();
+ expression (const struct language_defn *lang, struct gdbarch *arch)
+ : language_defn (lang),
+ gdbarch (arch)
+ {
+ }
+
DISABLE_COPY_AND_ASSIGN (expression);
- void resize (size_t);
+ /* Return the opcode for the outermost sub-expression of this
+ expression. */
+ enum exp_opcode first_opcode () const
+ {
+ return op->opcode ();
+ }
+
+ /* Evaluate the expression. EXPECT_TYPE is the context type of the
+ expression; normally this should be nullptr. NOSIDE controls how
+ evaluation is performed. */
+ struct value *evaluate (struct type *expect_type, enum noside noside);
/* Language it was entered in. */
const struct language_defn *language_defn;
/* Architecture it was parsed in. */
struct gdbarch *gdbarch;
- int nelts = 0;
- union exp_element *elts;
+ expr::operation_up op;
};
typedef std::unique_ptr<expression> expression_up;
-/* Macros for converting between number of expression elements and bytes
- to store that many expression elements. */
-
-#define EXP_ELEM_TO_BYTES(elements) \
- ((elements) * sizeof (union exp_element))
-#define BYTES_TO_EXP_ELEM(bytes) \
- (((bytes) + sizeof (union exp_element) - 1) / sizeof (union exp_element))
-
/* From parse.c */
class innermost_block_tracker;
extern expression_up parse_expression (const char *,
- innermost_block_tracker * = nullptr);
+ innermost_block_tracker * = nullptr,
+ bool void_context_p = false);
extern expression_up parse_expression_with_language (const char *string,
enum language lang);
-extern struct type *parse_expression_for_completion
- (const char *, gdb::unique_xmalloc_ptr<char> *, enum type_code *);
+
+class completion_tracker;
+
+/* Base class for expression completion. An instance of this
+ represents a completion request from the parser. */
+struct expr_completion_base
+{
+ /* Perform this object's completion. EXP is the expression in which
+ the completion occurs. TRACKER is the tracker to update with the
+ results. Return true if completion was possible (even if no
+ completions were found), false to fall back to ordinary
+ expression completion (i.e., symbol names). */
+ virtual bool complete (struct expression *exp,
+ completion_tracker &tracker) = 0;
+
+ virtual ~expr_completion_base () = default;
+};
+
+extern expression_up parse_expression_for_completion
+ (const char *, std::unique_ptr<expr_completion_base> *completer);
class innermost_block_tracker;
extern expression_up parse_exp_1 (const char **, CORE_ADDR pc,
/* From eval.c */
-/* Values of NOSIDE argument to eval_subexp. */
-
-enum noside
- {
- EVAL_NORMAL,
- EVAL_SKIP, /* Only effect is to increment pos.
- Return type information where
- possible. */
- EVAL_AVOID_SIDE_EFFECTS /* Don't modify any variables or
- call any functions. The value
- returned will have the correct
- type, and will have an
- approximately correct lvalue
- type (inaccuracy: anything that is
- listed as being in a register in
- the function in which it was
- declared will be lval_register).
- Ideally this would not even read
- target memory, but currently it
- does in many situations. */
- };
-
-extern struct value *evaluate_subexp_standard
- (struct type *, struct expression *, int *, enum noside);
-
/* Evaluate a function call. The function to be called is in CALLEE and
the arguments passed to the function are in ARGVEC.
FUNCTION_NAME is the name of the function, if known.
/* From expprint.c */
-extern void print_expression (struct expression *, struct ui_file *);
-
extern const char *op_name (enum exp_opcode opcode);
-extern const char *op_string (enum exp_opcode);
-
-extern void dump_raw_expression (struct expression *,
- struct ui_file *, const char *);
extern void dump_prefix_expression (struct expression *, struct ui_file *);
/* In an OP_RANGE expression, either bound could be empty, indicating
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