387 lines
14 KiB
C
387 lines
14 KiB
C
/* Definitions for expressions stored in reversed prefix form, for GDB.
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Copyright 1986, 1989, 1992, 1994 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 2 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, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
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#if !defined (EXPRESSION_H)
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#define EXPRESSION_H 1
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#ifdef __STDC__
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struct block; /* Forward declaration for prototypes */
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#endif
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/* Definitions for saved C expressions. */
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/* An expression is represented as a vector of union exp_element's.
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Each exp_element is an opcode, except that some opcodes cause
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the following exp_element to be treated as a long or double constant
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or as a variable. The opcodes are obeyed, using a stack for temporaries.
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The value is left on the temporary stack at the end. */
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/* When it is necessary to include a string,
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it can occupy as many exp_elements as it needs.
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We find the length of the string using strlen,
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divide to find out how many exp_elements are used up,
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and skip that many. Strings, like numbers, are indicated
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by the preceding opcode. */
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enum exp_opcode
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{
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/* Used when it's necessary to pass an opcode which will be ignored,
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or to catch uninitialized values. */
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OP_NULL,
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/* BINOP_... operate on two values computed by following subexpressions,
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replacing them by one result value. They take no immediate arguments. */
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BINOP_ADD, /* + */
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BINOP_SUB, /* - */
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BINOP_MUL, /* * */
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BINOP_DIV, /* / */
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BINOP_REM, /* % */
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BINOP_MOD, /* mod (Knuth 1.2.4) */
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BINOP_LSH, /* << */
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BINOP_RSH, /* >> */
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BINOP_LOGICAL_AND, /* && */
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BINOP_LOGICAL_OR, /* || */
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BINOP_BITWISE_AND, /* & */
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BINOP_BITWISE_IOR, /* | */
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BINOP_BITWISE_XOR, /* ^ */
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BINOP_EQUAL, /* == */
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BINOP_NOTEQUAL, /* != */
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BINOP_LESS, /* < */
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BINOP_GTR, /* > */
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BINOP_LEQ, /* <= */
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BINOP_GEQ, /* >= */
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BINOP_REPEAT, /* @ */
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BINOP_ASSIGN, /* = */
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BINOP_COMMA, /* , */
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BINOP_SUBSCRIPT, /* x[y] */
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BINOP_EXP, /* Exponentiation */
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/* C++. */
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BINOP_MIN, /* <? */
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BINOP_MAX, /* >? */
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BINOP_SCOPE, /* :: */
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/* STRUCTOP_MEMBER is used for pointer-to-member constructs.
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X . * Y translates into X STRUCTOP_MEMBER Y. */
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STRUCTOP_MEMBER,
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/* STRUCTOP_MPTR is used for pointer-to-member constructs
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when X is a pointer instead of an aggregate. */
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STRUCTOP_MPTR,
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/* end of C++. */
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/* For Modula-2 integer division DIV */
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BINOP_INTDIV,
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BINOP_ASSIGN_MODIFY, /* +=, -=, *=, and so on.
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The following exp_element is another opcode,
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a BINOP_, saying how to modify.
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Then comes another BINOP_ASSIGN_MODIFY,
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making three exp_elements in total. */
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/* Modula-2 standard (binary) procedures */
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BINOP_VAL,
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BINOP_INCL,
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BINOP_EXCL,
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/* Concatenate two operands, such as character strings or bitstrings.
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If the first operand is a integer expression, then it means concatenate
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the second operand with itself that many times. */
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BINOP_CONCAT,
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/* For Chill and Pascal. */
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BINOP_IN, /* Returns 1 iff ARG1 IN ARG2. */
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/* This is the "colon operator" used various places in Chill. */
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BINOP_RANGE,
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/* This must be the highest BINOP_ value, for expprint.c. */
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BINOP_END,
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/* Operates on three values computed by following subexpressions. */
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TERNOP_COND, /* ?: */
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/* A sub-string/sub-array. Chill syntax: OP1(OP2:OP3).
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Return elements OP2 through OP3 of OP1. */
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TERNOP_SLICE,
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/* A sub-string/sub-array. Chill syntax: OP1(OP2 UP OP3).
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Return OP3 elements of OP1, starting with element OP2. */
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TERNOP_SLICE_COUNT,
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/* Multidimensional subscript operator, such as Modula-2 x[a,b,...].
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The dimensionality is encoded in the operator, like the number of
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function arguments in OP_FUNCALL, I.E. <OP><dimension><OP>.
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The value of the first following subexpression is subscripted
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by each of the next following subexpressions, one per dimension. */
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MULTI_SUBSCRIPT,
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/* The OP_... series take immediate following arguments.
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After the arguments come another OP_... (the same one)
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so that the grouping can be recognized from the end. */
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/* OP_LONG is followed by a type pointer in the next exp_element
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and the long constant value in the following exp_element.
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Then comes another OP_LONG.
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Thus, the operation occupies four exp_elements. */
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OP_LONG,
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/* OP_DOUBLE is similar but takes a DOUBLEST constant instead of a long. */
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OP_DOUBLE,
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/* OP_VAR_VALUE takes one struct block * in the following element,
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and one struct symbol * in the following exp_element, followed by
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another OP_VAR_VALUE, making four exp_elements. If the block is
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non-NULL, evaluate the symbol relative to the innermost frame
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executing in that block; if the block is NULL use the selected frame. */
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OP_VAR_VALUE,
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/* OP_LAST is followed by an integer in the next exp_element.
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The integer is zero for the last value printed,
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or it is the absolute number of a history element.
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With another OP_LAST at the end, this makes three exp_elements. */
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OP_LAST,
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/* OP_REGISTER is followed by an integer in the next exp_element.
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This is the number of a register to fetch (as an int).
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With another OP_REGISTER at the end, this makes three exp_elements. */
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OP_REGISTER,
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/* OP_INTERNALVAR is followed by an internalvar ptr in the next exp_element.
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With another OP_INTERNALVAR at the end, this makes three exp_elements. */
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OP_INTERNALVAR,
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/* OP_FUNCALL is followed by an integer in the next exp_element.
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The integer is the number of args to the function call.
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That many plus one values from following subexpressions
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are used, the first one being the function.
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The integer is followed by a repeat of OP_FUNCALL,
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making three exp_elements. */
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OP_FUNCALL,
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/* This is EXACTLY like OP_FUNCALL but is semantically different.
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In F77, array subscript expressions, substring expressions
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and function calls are all exactly the same syntactically. They may
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only be dismabiguated at runtime. Thus this operator, which
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indicates that we have found something of the form <name> ( <stuff> ) */
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OP_F77_UNDETERMINED_ARGLIST,
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/* The following OP is a special one, it introduces a F77 complex
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literal. It is followed by exactly two args that are doubles. */
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OP_COMPLEX,
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/* OP_STRING represents a string constant.
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Its format is the same as that of a STRUCTOP, but the string
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data is just made into a string constant when the operation
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is executed. */
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OP_STRING,
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/* OP_BITSTRING represents a packed bitstring constant.
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Its format is the same as that of a STRUCTOP, but the bitstring
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data is just made into a bitstring constant when the operation
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is executed. */
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OP_BITSTRING,
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/* OP_ARRAY creates an array constant out of the following subexpressions.
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It is followed by two exp_elements, the first containing an integer
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that is the lower bound of the array and the second containing another
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integer that is the upper bound of the array. The second integer is
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followed by a repeat of OP_ARRAY, making four exp_elements total.
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The bounds are used to compute the number of following subexpressions
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to consume, as well as setting the bounds in the created array constant.
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The type of the elements is taken from the type of the first subexp,
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and they must all match. */
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OP_ARRAY,
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/* UNOP_CAST is followed by a type pointer in the next exp_element.
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With another UNOP_CAST at the end, this makes three exp_elements.
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It casts the value of the following subexpression. */
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UNOP_CAST,
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/* UNOP_MEMVAL is followed by a type pointer in the next exp_element
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With another UNOP_MEMVAL at the end, this makes three exp_elements.
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It casts the contents of the word addressed by the value of the
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following subexpression. */
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UNOP_MEMVAL,
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/* UNOP_... operate on one value from a following subexpression
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and replace it with a result. They take no immediate arguments. */
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UNOP_NEG, /* Unary - */
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UNOP_LOGICAL_NOT, /* Unary ! */
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UNOP_COMPLEMENT, /* Unary ~ */
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UNOP_IND, /* Unary * */
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UNOP_ADDR, /* Unary & */
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UNOP_PREINCREMENT, /* ++ before an expression */
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UNOP_POSTINCREMENT, /* ++ after an expression */
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UNOP_PREDECREMENT, /* -- before an expression */
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UNOP_POSTDECREMENT, /* -- after an expression */
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UNOP_SIZEOF, /* Unary sizeof (followed by expression) */
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UNOP_PLUS, /* Unary plus */
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UNOP_CAP, /* Modula-2 standard (unary) procedures */
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UNOP_CHR,
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UNOP_ORD,
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UNOP_ABS,
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UNOP_FLOAT,
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UNOP_HIGH,
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UNOP_MAX,
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UNOP_MIN,
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UNOP_ODD,
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UNOP_TRUNC,
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/* Chill builtin functions. */
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UNOP_LOWER, UNOP_UPPER, UNOP_LENGTH, UNOP_CARD, UNOP_CHMAX, UNOP_CHMIN,
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OP_BOOL, /* Modula-2 builtin BOOLEAN type */
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OP_M2_STRING, /* Modula-2 string constants */
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/* STRUCTOP_... operate on a value from a following subexpression
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by extracting a structure component specified by a string
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that appears in the following exp_elements (as many as needed).
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STRUCTOP_STRUCT is used for "." and STRUCTOP_PTR for "->".
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They differ only in the error message given in case the value is
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not suitable or the structure component specified is not found.
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The length of the string follows the opcode, followed by
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BYTES_TO_EXP_ELEM(length) elements containing the data of the
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string, followed by the length again and the opcode again. */
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STRUCTOP_STRUCT,
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STRUCTOP_PTR,
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/* C++ */
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/* OP_THIS is just a placeholder for the class instance variable.
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It just comes in a tight (OP_THIS, OP_THIS) pair. */
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OP_THIS,
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/* OP_SCOPE surrounds a type name and a field name. The type
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name is encoded as one element, but the field name stays as
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a string, which, of course, is variable length. */
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OP_SCOPE,
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/* Used to represent named structure field values in brace initializers
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(or tuples as they are called in Chill).
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The gcc C syntax is NAME:VALUE or .NAME=VALUE, the Chill syntax is
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.NAME:VALUE. Multiple labels (as in the Chill syntax
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.NAME1,.NAME2:VALUE) is represented as if it were
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.NAME1:(.NAME2:VALUE) (though that is not valid Chill syntax).
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The NAME is represented as for STRUCTOP_STRUCT; VALUE follows. */
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OP_LABELED,
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/* OP_TYPE is for parsing types, and used with the "ptype" command
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so we can look up types that are qualified by scope, either with
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the GDB "::" operator, or the Modula-2 '.' operator. */
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OP_TYPE,
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/* An un-looked-up identifier. */
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OP_NAME,
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/* An unparsed expression. Used for Scheme (for now at least) */
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OP_EXPRSTRING
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};
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union exp_element
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{
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enum exp_opcode opcode;
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struct symbol *symbol;
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LONGEST longconst;
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DOUBLEST doubleconst;
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/* Really sizeof (union exp_element) characters (or less for the last
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element of a string). */
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char string;
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struct type *type;
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struct internalvar *internalvar;
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struct block *block;
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};
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struct expression
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{
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const struct language_defn *language_defn; /* language it was entered in */
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int nelts;
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union exp_element elts[1];
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};
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/* Macros for converting between number of expression elements and bytes
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to store that many expression elements. */
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#define EXP_ELEM_TO_BYTES(elements) \
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((elements) * sizeof (union exp_element))
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#define BYTES_TO_EXP_ELEM(bytes) \
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(((bytes) + sizeof (union exp_element) - 1) / sizeof (union exp_element))
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/* From parse.c */
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extern struct expression *parse_expression PARAMS ((char *));
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extern struct expression *parse_exp_1 PARAMS ((char **, struct block *, int));
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/* The innermost context required by the stack and register variables
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we've encountered so far. To use this, set it to NULL, then call
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parse_<whatever>, then look at it. */
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extern struct block *innermost_block;
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/* From eval.c */
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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_SKIP, /* Only effect is to increment pos. */
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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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};
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extern struct value* evaluate_subexp_standard
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PARAMS ((struct type *, struct expression *, int*, enum noside));
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/* From expprint.c */
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extern void print_expression PARAMS ((struct expression *, GDB_FILE *));
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extern char *op_string PARAMS ((enum exp_opcode));
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/* To enable dumping of all parsed expressions in a human readable
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form, define DEBUG_EXPRESSIONS. This is a compile time constant
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at the moment, since it's not clear that this feature is important
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enough to include by default. */
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#ifdef DEBUG_EXPRESSIONS
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extern void dump_expression PARAMS ((struct expression *, GDB_FILE *, char *));
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#define DUMP_EXPRESSION(exp,file,note) dump_expression ((exp), (file), (note))
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#else
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#define DUMP_EXPRESSION(exp,file,note) /* Null expansion */
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#endif /* DEBUG_EXPRESSIONS */
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#endif /* !defined (EXPRESSION_H) */
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