/* Definitions for expressions stored in reversed prefix form, for GDB.
- Copyright 1986, 1989, 1992, 1994, 2000 Free Software Foundation, Inc.
+
+ Copyright (C) 1986-2022 Free Software Foundation, Inc.
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2 of the License, or
+ the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
- along with this program; if not, write to the Free Software
- Foundation, Inc., 59 Temple Place - Suite 330,
- Boston, MA 02111-1307, USA. */
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
#if !defined (EXPRESSION_H)
#define EXPRESSION_H 1
+#include "gdbtypes.h"
-#include "symtab.h" /* Needed for "struct block" type. */
-#include "doublest.h" /* Needed for DOUBLEST. */
-
+/* While parsing expressions we need to track the innermost lexical block
+ that we encounter. In some situations we need to track the innermost
+ block just for symbols, and in other situations we want to track the
+ innermost block for symbols and registers. These flags are used by the
+ innermost block tracker to control which blocks we consider for the
+ innermost block. These flags can be combined together as needed. */
-/* Definitions for saved C expressions. */
+enum innermost_block_tracker_type
+{
+ /* Track the innermost block for symbols within an expression. */
+ INNERMOST_BLOCK_FOR_SYMBOLS = (1 << 0),
-/* 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. */
+ /* Track the innermost block for registers within an expression. */
+ INNERMOST_BLOCK_FOR_REGISTERS = (1 << 1)
+};
+DEF_ENUM_FLAGS_TYPE (enum innermost_block_tracker_type,
+ innermost_block_tracker_types);
-/* 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
+enum exp_opcode : uint8_t
{
- /* Used when it's necessary to pass an opcode which will be ignored,
- or to catch uninitialized values. */
- OP_NULL,
-
-/* BINOP_... operate on two values computed by following subexpressions,
- replacing them by one result value. They take no immediate arguments. */
-
- BINOP_ADD, /* + */
- BINOP_SUB, /* - */
- BINOP_MUL, /* * */
- BINOP_DIV, /* / */
- BINOP_REM, /* % */
- BINOP_MOD, /* mod (Knuth 1.2.4) */
- BINOP_LSH, /* << */
- BINOP_RSH, /* >> */
- BINOP_LOGICAL_AND, /* && */
- BINOP_LOGICAL_OR, /* || */
- BINOP_BITWISE_AND, /* & */
- BINOP_BITWISE_IOR, /* | */
- BINOP_BITWISE_XOR, /* ^ */
- BINOP_EQUAL, /* == */
- BINOP_NOTEQUAL, /* != */
- BINOP_LESS, /* < */
- BINOP_GTR, /* > */
- BINOP_LEQ, /* <= */
- BINOP_GEQ, /* >= */
- BINOP_REPEAT, /* @ */
- BINOP_ASSIGN, /* = */
- BINOP_COMMA, /* , */
- BINOP_SUBSCRIPT, /* x[y] */
- BINOP_EXP, /* Exponentiation */
-
- /* C++. */
-
- BINOP_MIN, /* <? */
- BINOP_MAX, /* >? */
-
- /* STRUCTOP_MEMBER is used for pointer-to-member constructs.
- X . * Y translates into X STRUCTOP_MEMBER Y. */
- STRUCTOP_MEMBER,
-
- /* STRUCTOP_MPTR is used for pointer-to-member constructs
- when X is a pointer instead of an aggregate. */
- STRUCTOP_MPTR,
-
- /* end of C++. */
-
- /* For Modula-2 integer division DIV */
- BINOP_INTDIV,
-
- BINOP_ASSIGN_MODIFY, /* +=, -=, *=, and so on.
- The following exp_element is another opcode,
- a BINOP_, saying how to modify.
- Then comes another BINOP_ASSIGN_MODIFY,
- making three exp_elements in total. */
-
- /* Modula-2 standard (binary) procedures */
- BINOP_VAL,
- BINOP_INCL,
- BINOP_EXCL,
-
- /* Concatenate two operands, such as character strings or bitstrings.
- If the first operand is a integer expression, then it means concatenate
- the second operand with itself that many times. */
- BINOP_CONCAT,
-
- /* For Chill and Pascal. */
- BINOP_IN, /* Returns 1 iff ARG1 IN ARG2. */
-
- /* This is the "colon operator" used various places in Chill. */
- BINOP_RANGE,
-
- /* This must be the highest BINOP_ value, for expprint.c. */
- BINOP_END,
-
- /* Operates on three values computed by following subexpressions. */
- TERNOP_COND, /* ?: */
-
- /* A sub-string/sub-array. Chill syntax: OP1(OP2:OP3).
- Return elements OP2 through OP3 of OP1. */
- TERNOP_SLICE,
-
- /* A sub-string/sub-array. Chill syntax: OP1(OP2 UP OP3).
- Return OP3 elements of OP1, starting with element OP2. */
- TERNOP_SLICE_COUNT,
-
- /* Multidimensional subscript operator, such as Modula-2 x[a,b,...].
- The dimensionality is encoded in the operator, like the number of
- function arguments in OP_FUNCALL, I.E. <OP><dimension><OP>.
- The value of the first following subexpression is subscripted
- by each of the next following subexpressions, one per dimension. */
- MULTI_SUBSCRIPT,
-
- /* The OP_... series take immediate following arguments.
- After the arguments come another OP_... (the same one)
- so that the grouping can be recognized from the end. */
-
- /* OP_LONG is followed by a type pointer in the next exp_element
- and the long constant value in the following exp_element.
- Then comes another OP_LONG.
- Thus, the operation occupies four exp_elements. */
- OP_LONG,
-
- /* OP_DOUBLE is similar but takes a DOUBLEST constant instead of a long. */
- OP_DOUBLE,
-
- /* OP_VAR_VALUE takes one struct block * in the following element,
- and one struct symbol * in the following exp_element, followed by
- another OP_VAR_VALUE, making four exp_elements. If the block is
- non-NULL, evaluate the symbol relative to the innermost frame
- executing in that block; if the block is NULL use the selected frame. */
- OP_VAR_VALUE,
-
- /* OP_LAST is followed by an integer in the next exp_element.
- The integer is zero for the last value printed,
- or it is the absolute number of a history element.
- With another OP_LAST at the end, this makes three exp_elements. */
- OP_LAST,
-
- /* OP_REGISTER is followed by an integer in the next exp_element.
- This is the number of a register to fetch (as an int).
- With another OP_REGISTER at the end, this makes three exp_elements. */
- OP_REGISTER,
-
- /* OP_INTERNALVAR is followed by an internalvar ptr in the next exp_element.
- With another OP_INTERNALVAR at the end, this makes three exp_elements. */
- OP_INTERNALVAR,
-
- /* OP_FUNCALL is followed by an integer in the next exp_element.
- The integer is the number of args to the function call.
- That many plus one values from following subexpressions
- are used, the first one being the function.
- The integer is followed by a repeat of OP_FUNCALL,
- making three exp_elements. */
- OP_FUNCALL,
-
- /* This is EXACTLY like OP_FUNCALL but is semantically different.
- In F77, array subscript expressions, substring expressions
- and function calls are all exactly the same syntactically. They may
- only be dismabiguated at runtime. Thus this operator, which
- indicates that we have found something of the form <name> ( <stuff> ) */
- OP_F77_UNDETERMINED_ARGLIST,
-
- /* The following OP is a special one, it introduces a F77 complex
- literal. It is followed by exactly two args that are doubles. */
- OP_COMPLEX,
-
- /* OP_STRING represents a string constant.
- Its format is the same as that of a STRUCTOP, but the string
- data is just made into a string constant when the operation
- is executed. */
- OP_STRING,
-
- /* OP_BITSTRING represents a packed bitstring constant.
- Its format is the same as that of a STRUCTOP, but the bitstring
- data is just made into a bitstring constant when the operation
- is executed. */
- OP_BITSTRING,
-
- /* OP_ARRAY creates an array constant out of the following subexpressions.
- It is followed by two exp_elements, the first containing an integer
- that is the lower bound of the array and the second containing another
- integer that is the upper bound of the array. The second integer is
- followed by a repeat of OP_ARRAY, making four exp_elements total.
- The bounds are used to compute the number of following subexpressions
- to consume, as well as setting the bounds in the created array constant.
- The type of the elements is taken from the type of the first subexp,
- and they must all match. */
- OP_ARRAY,
-
- /* UNOP_CAST is followed by a type pointer in the next exp_element.
- With another UNOP_CAST at the end, this makes three exp_elements.
- It casts the value of the following subexpression. */
- UNOP_CAST,
-
- /* UNOP_MEMVAL is followed by a type pointer in the next exp_element
- With another UNOP_MEMVAL at the end, this makes three exp_elements.
- It casts the contents of the word addressed by the value of the
- following subexpression. */
- UNOP_MEMVAL,
-
- /* UNOP_... operate on one value from a following subexpression
- and replace it with a result. They take no immediate arguments. */
-
- UNOP_NEG, /* Unary - */
- UNOP_LOGICAL_NOT, /* Unary ! */
- UNOP_COMPLEMENT, /* Unary ~ */
- UNOP_IND, /* Unary * */
- UNOP_ADDR, /* Unary & */
- UNOP_PREINCREMENT, /* ++ before an expression */
- UNOP_POSTINCREMENT, /* ++ after an expression */
- UNOP_PREDECREMENT, /* -- before an expression */
- UNOP_POSTDECREMENT, /* -- after an expression */
- UNOP_SIZEOF, /* Unary sizeof (followed by expression) */
-
- UNOP_PLUS, /* Unary plus */
-
- UNOP_CAP, /* Modula-2 standard (unary) procedures */
- UNOP_CHR,
- UNOP_ORD,
- UNOP_ABS,
- UNOP_FLOAT,
- UNOP_HIGH,
- UNOP_MAX,
- UNOP_MIN,
- UNOP_ODD,
- UNOP_TRUNC,
-
- /* Chill builtin functions. */
- UNOP_LOWER, UNOP_UPPER, UNOP_LENGTH, UNOP_CARD, UNOP_CHMAX, UNOP_CHMIN,
-
- OP_BOOL, /* Modula-2 builtin BOOLEAN type */
- OP_M2_STRING, /* Modula-2 string constants */
-
- /* STRUCTOP_... operate on a value from a following subexpression
- by extracting a structure component specified by a string
- that appears in the following exp_elements (as many as needed).
- STRUCTOP_STRUCT is used for "." and STRUCTOP_PTR for "->".
- They differ only in the error message given in case the value is
- not suitable or the structure component specified is not found.
-
- The length of the string follows the opcode, followed by
- BYTES_TO_EXP_ELEM(length) elements containing the data of the
- string, followed by the length again and the opcode again. */
-
- STRUCTOP_STRUCT,
- STRUCTOP_PTR,
-
- /* C++ */
- /* OP_THIS is just a placeholder for the class instance variable.
- It just comes in a tight (OP_THIS, OP_THIS) pair. */
- OP_THIS,
-
- /* OP_SCOPE surrounds a type name and a field name. The type
- name is encoded as one element, but the field name stays as
- a string, which, of course, is variable length. */
- OP_SCOPE,
-
- /* Used to represent named structure field values in brace initializers
- (or tuples as they are called in Chill).
- The gcc C syntax is NAME:VALUE or .NAME=VALUE, the Chill syntax is
- .NAME:VALUE. Multiple labels (as in the Chill syntax
- .NAME1,.NAME2:VALUE) is represented as if it were
- .NAME1:(.NAME2:VALUE) (though that is not valid Chill syntax).
-
- The NAME is represented as for STRUCTOP_STRUCT; VALUE follows. */
- OP_LABELED,
-
- /* OP_TYPE is for parsing types, and used with the "ptype" command
- so we can look up types that are qualified by scope, either with
- the GDB "::" operator, or the Modula-2 '.' operator. */
- OP_TYPE,
-
- /* An un-looked-up identifier. */
- OP_NAME,
-
- /* An unparsed expression. Used for Scheme (for now at least) */
- OP_EXPRSTRING
- };
+#define OP(name) name ,
-union exp_element
- {
- enum exp_opcode opcode;
- struct symbol *symbol;
- LONGEST longconst;
- DOUBLEST doubleconst;
- /* Really sizeof (union exp_element) characters (or less for the last
- element of a string). */
- char string;
- struct type *type;
- struct internalvar *internalvar;
- struct block *block;
- };
+#include "std-operator.def"
-struct expression
- {
- const struct language_defn *language_defn; /* language it was entered in */
- int nelts;
- union exp_element elts[1];
+#undef OP
};
-/* 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 */
-
-extern struct expression *parse_expression (char *);
-
-extern struct expression *parse_exp_1 (char **, struct block *, int);
-
-/* The innermost context required by the stack and register variables
- we've encountered so far. To use this, set it to NULL, then call
- parse_<whatever>, then look at it. */
-extern struct block *innermost_block;
-
-/* From eval.c */
-
/* Values of NOSIDE argument to eval_subexp. */
enum noside
{
EVAL_NORMAL,
- EVAL_SKIP, /* Only effect is to increment pos. */
EVAL_AVOID_SIDE_EFFECTS /* Don't modify any variables or
call any functions. The value
returned will have the correct
type (inaccuracy: anything that is
listed as being in a register in
the function in which it was
- declared will be lval_register). */
+ 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);
+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 *lang, struct gdbarch *arch)
+ : language_defn (lang),
+ gdbarch (arch)
+ {
+ }
+
+ DISABLE_COPY_AND_ASSIGN (expression);
+
+ /* 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;
+ expr::operation_up op;
+};
+
+typedef std::unique_ptr<expression> expression_up;
+
+/* From parse.c */
+
+class innermost_block_tracker;
+extern expression_up parse_expression (const char *,
+ innermost_block_tracker * = nullptr,
+ bool void_context_p = false);
+
+extern expression_up parse_expression_with_language (const char *string,
+ enum language lang);
+
+
+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,
+ const struct block *, int,
+ innermost_block_tracker * = nullptr);
+
+/* From eval.c */
+
+/* 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.
+ DEFAULT_RETURN_TYPE is used as the function's return type if the return
+ type is unknown. */
+
+extern struct value *evaluate_subexp_do_call (expression *exp,
+ enum noside noside,
+ value *callee,
+ gdb::array_view<value *> argvec,
+ const char *function_name,
+ type *default_return_type);
/* From expprint.c */
-extern void print_expression (struct expression *, struct ui_file *);
+extern const char *op_name (enum exp_opcode opcode);
+
+extern void dump_prefix_expression (struct expression *, struct ui_file *);
+
+/* In an OP_RANGE expression, either bound could be empty, indicating
+ that its value is by default that of the corresponding bound of the
+ array or string. Also, the upper end of the range can be exclusive
+ or inclusive. So we have six sorts of subrange. This enumeration
+ type is to identify this. */
+
+enum range_flag : unsigned
+{
+ /* This is a standard range. Both the lower and upper bounds are
+ defined, and the bounds are inclusive. */
+ RANGE_STANDARD = 0,
+
+ /* The low bound was not given. */
+ RANGE_LOW_BOUND_DEFAULT = 1 << 0,
+
+ /* The high bound was not given. */
+ RANGE_HIGH_BOUND_DEFAULT = 1 << 1,
+
+ /* The high bound of this range is exclusive. */
+ RANGE_HIGH_BOUND_EXCLUSIVE = 1 << 2,
-extern char *op_string (enum exp_opcode);
+ /* The range has a stride. */
+ RANGE_HAS_STRIDE = 1 << 3,
+};
-extern void dump_prefix_expression (struct expression *,
- struct ui_file *,
- char *);
-extern void dump_postfix_expression (struct expression *,
- struct ui_file *,
- char *);
+DEF_ENUM_FLAGS_TYPE (enum range_flag, range_flags);
#endif /* !defined (EXPRESSION_H) */
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