1 // expressions.h -- Go frontend expression handling. -*- C++ -*-
3 // Copyright 2009 The Go Authors. All rights reserved.
4 // Use of this source code is governed by a BSD-style
5 // license that can be found in the LICENSE file.
7 #ifndef GO_EXPRESSIONS_H
8 #define GO_EXPRESSIONS_H
16 class Translate_context;
18 class Statement_inserter;
25 class Expression_list;
27 class Temporary_reference_expression;
28 class String_expression;
29 class Binary_expression;
30 class Call_expression;
31 class Func_expression;
32 class Unknown_expression;
33 class Index_expression;
34 class Map_index_expression;
35 class Bound_method_expression;
36 class Field_reference_expression;
37 class Interface_field_reference_expression;
38 class Type_guard_expression;
39 class Receive_expression;
43 class Temporary_statement;
45 class Ast_dump_context;
48 // The base class for all expressions.
53 // The types of expressions.
54 enum Expression_classification
60 EXPRESSION_CONST_REFERENCE,
61 EXPRESSION_VAR_REFERENCE,
62 EXPRESSION_TEMPORARY_REFERENCE,
64 EXPRESSION_FUNC_REFERENCE,
65 EXPRESSION_UNKNOWN_REFERENCE,
74 EXPRESSION_CALL_RESULT,
75 EXPRESSION_BOUND_METHOD,
77 EXPRESSION_ARRAY_INDEX,
78 EXPRESSION_STRING_INDEX,
81 EXPRESSION_FIELD_REFERENCE,
82 EXPRESSION_INTERFACE_FIELD_REFERENCE,
83 EXPRESSION_ALLOCATION,
84 EXPRESSION_TYPE_GUARD,
85 EXPRESSION_CONVERSION,
86 EXPRESSION_UNSAFE_CONVERSION,
87 EXPRESSION_STRUCT_CONSTRUCTION,
88 EXPRESSION_FIXED_ARRAY_CONSTRUCTION,
89 EXPRESSION_OPEN_ARRAY_CONSTRUCTION,
90 EXPRESSION_MAP_CONSTRUCTION,
91 EXPRESSION_COMPOSITE_LITERAL,
92 EXPRESSION_HEAP_COMPOSITE,
94 EXPRESSION_TYPE_DESCRIPTOR,
96 EXPRESSION_STRUCT_FIELD_OFFSET,
97 EXPRESSION_MAP_DESCRIPTOR,
101 Expression(Expression_classification, source_location);
103 virtual ~Expression();
105 // Make an error expression. This is used when a parse error occurs
106 // to prevent cascading errors.
108 make_error(source_location);
110 // Make an expression which is really a type. This is used during
113 make_type(Type*, source_location);
115 // Make a unary expression.
117 make_unary(Operator, Expression*, source_location);
119 // Make a binary expression.
121 make_binary(Operator, Expression*, Expression*, source_location);
123 // Make a reference to a constant in an expression.
125 make_const_reference(Named_object*, source_location);
127 // Make a reference to a variable in an expression.
129 make_var_reference(Named_object*, source_location);
131 // Make a reference to a temporary variable. Temporary variables
132 // are always created by a single statement, which is what we use to
134 static Temporary_reference_expression*
135 make_temporary_reference(Temporary_statement*, source_location);
137 // Make a sink expression--a reference to the blank identifier _.
139 make_sink(source_location);
141 // Make a reference to a function in an expression.
143 make_func_reference(Named_object*, Expression* closure, source_location);
145 // Make a reference to an unknown name. In a correct program this
146 // will always be lowered to a real const/var/func reference.
148 make_unknown_reference(Named_object*, source_location);
150 // Make a constant bool expression.
152 make_boolean(bool val, source_location);
154 // Make a constant string expression.
156 make_string(const std::string&, source_location);
158 // Make a constant integer expression. TYPE should be NULL for an
161 make_integer(const mpz_t*, Type*, source_location);
163 // Make a constant float expression. TYPE should be NULL for an
166 make_float(const mpfr_t*, Type*, source_location);
168 // Make a constant complex expression. TYPE should be NULL for an
171 make_complex(const mpfr_t* real, const mpfr_t* imag, Type*, source_location);
173 // Make a nil expression.
175 make_nil(source_location);
177 // Make an iota expression. This is used for the predeclared
182 // Make a call expression.
183 static Call_expression*
184 make_call(Expression* func, Expression_list* args, bool is_varargs,
187 // Make a reference to a specific result of a call expression which
190 make_call_result(Call_expression*, unsigned int index);
192 // Make an expression which is a method bound to its first
194 static Bound_method_expression*
195 make_bound_method(Expression* object, Expression* method, source_location);
197 // Make an index or slice expression. This is a parser expression
198 // which represents LEFT[START:END]. END may be NULL, meaning an
199 // index rather than a slice. At parse time we may not know the
200 // type of LEFT. After parsing this is lowered to an array index, a
201 // string index, or a map index.
203 make_index(Expression* left, Expression* start, Expression* end,
206 // Make an array index expression. END may be NULL, in which case
207 // this is an lvalue.
209 make_array_index(Expression* array, Expression* start, Expression* end,
212 // Make a string index expression. END may be NULL. This is never
215 make_string_index(Expression* string, Expression* start, Expression* end,
218 // Make a map index expression. This is an lvalue.
219 static Map_index_expression*
220 make_map_index(Expression* map, Expression* val, source_location);
222 // Make a selector. This is a parser expression which represents
223 // LEFT.NAME. At parse time we may not know the type of the left
226 make_selector(Expression* left, const std::string& name, source_location);
228 // Make a reference to a field in a struct.
229 static Field_reference_expression*
230 make_field_reference(Expression*, unsigned int field_index, source_location);
232 // Make a reference to a field of an interface, with an associated
235 make_interface_field_reference(Expression*, const std::string&,
238 // Make an allocation expression.
240 make_allocation(Type*, source_location);
242 // Make a type guard expression.
244 make_type_guard(Expression*, Type*, source_location);
246 // Make a type cast expression.
248 make_cast(Type*, Expression*, source_location);
250 // Make an unsafe type cast expression. This is only used when
251 // passing parameter to builtin functions that are part of the Go
254 make_unsafe_cast(Type*, Expression*, source_location);
256 // Make a composite literal. The DEPTH parameter is how far down we
257 // are in a list of composite literals with omitted types.
259 make_composite_literal(Type*, int depth, bool has_keys, Expression_list*,
262 // Make a struct composite literal.
264 make_struct_composite_literal(Type*, Expression_list*, source_location);
266 // Make a slice composite literal.
268 make_slice_composite_literal(Type*, Expression_list*, source_location);
270 // Take a composite literal and allocate it on the heap.
272 make_heap_composite(Expression*, source_location);
274 // Make a receive expression. VAL is NULL for a unary receive.
275 static Receive_expression*
276 make_receive(Expression* channel, source_location);
278 // Make an expression which evaluates to the address of the type
279 // descriptor for TYPE.
281 make_type_descriptor(Type* type, source_location);
283 // Make an expression which evaluates to some characteristic of a
284 // type. These are only used for type descriptors, so there is no
285 // location parameter.
288 // The size of a value of the type.
290 // The required alignment of a value of the type.
292 // The required alignment of a value of the type when used as a
293 // field in a struct.
294 TYPE_INFO_FIELD_ALIGNMENT
298 make_type_info(Type* type, Type_info);
300 // Make an expression which evaluates to the offset of a field in a
301 // struct. This is only used for type descriptors, so there is no
302 // location parameter.
304 make_struct_field_offset(Struct_type*, const Struct_field*);
306 // Make an expression which evaluates to the address of the map
307 // descriptor for TYPE.
309 make_map_descriptor(Map_type* type, source_location);
311 // Make an expression which evaluates to the address of an unnamed
314 make_label_addr(Label*, source_location);
316 // Return the expression classification.
317 Expression_classification
318 classification() const
319 { return this->classification_; }
321 // Return the location of the expression.
324 { return this->location_; }
326 // Return whether this is a constant expression.
329 { return this->do_is_constant(); }
331 // If this is not a constant expression with integral type, return
332 // false. If it is one, return true, and set VAL to the value. VAL
333 // should already be initialized. If this returns true, it sets
334 // *PTYPE to the type of the value, or NULL for an abstract type.
335 // If IOTA_IS_CONSTANT is true, then an iota expression is assumed
336 // to have its final value.
338 integer_constant_value(bool iota_is_constant, mpz_t val, Type** ptype) const;
340 // If this is not a constant expression with floating point type,
341 // return false. If it is one, return true, and set VAL to the
342 // value. VAL should already be initialized. If this returns true,
343 // it sets *PTYPE to the type of the value, or NULL for an abstract
346 float_constant_value(mpfr_t val, Type** ptype) const;
348 // If this is not a constant expression with complex type, return
349 // false. If it is one, return true, and set REAL and IMAG to the
350 // value. REAL and IMAG should already be initialized. If this
351 // return strue, it sets *PTYPE to the type of the value, or NULL
352 // for an abstract type.
354 complex_constant_value(mpfr_t real, mpfr_t imag, Type** ptype) const;
356 // If this is not a constant expression with string type, return
357 // false. If it is one, return true, and set VAL to the value.
359 string_constant_value(std::string* val) const
360 { return this->do_string_constant_value(val); }
362 // This is called by the parser if the value of this expression is
363 // being discarded. This issues warnings about computed values
367 { this->do_discarding_value(); }
369 // Return whether this is an error expression.
371 is_error_expression() const
372 { return this->classification_ == EXPRESSION_ERROR; }
374 // Return whether this expression really represents a type.
376 is_type_expression() const
377 { return this->classification_ == EXPRESSION_TYPE; }
379 // If this is a variable reference, return the Var_expression
380 // structure. Otherwise, return NULL. This is a controlled dynamic
384 { return this->convert<Var_expression, EXPRESSION_VAR_REFERENCE>(); }
386 const Var_expression*
387 var_expression() const
388 { return this->convert<const Var_expression, EXPRESSION_VAR_REFERENCE>(); }
390 // If this is a reference to a temporary variable, return the
391 // Temporary_reference_expression. Otherwise, return NULL.
392 Temporary_reference_expression*
393 temporary_reference_expression()
395 return this->convert<Temporary_reference_expression,
396 EXPRESSION_TEMPORARY_REFERENCE>();
399 // Return whether this is a sink expression.
401 is_sink_expression() const
402 { return this->classification_ == EXPRESSION_SINK; }
404 // If this is a string expression, return the String_expression
405 // structure. Otherwise, return NULL.
408 { return this->convert<String_expression, EXPRESSION_STRING>(); }
410 // Return whether this is the expression nil.
412 is_nil_expression() const
413 { return this->classification_ == EXPRESSION_NIL; }
415 // If this is an indirection through a pointer, return the
416 // expression being pointed through. Otherwise return this.
420 // If this is a binary expression, return the Binary_expression
421 // structure. Otherwise return NULL.
424 { return this->convert<Binary_expression, EXPRESSION_BINARY>(); }
426 // If this is a call expression, return the Call_expression
427 // structure. Otherwise, return NULL. This is a controlled dynamic
431 { return this->convert<Call_expression, EXPRESSION_CALL>(); }
433 // If this is an expression which refers to a function, return the
434 // Func_expression structure. Otherwise, return NULL.
437 { return this->convert<Func_expression, EXPRESSION_FUNC_REFERENCE>(); }
439 const Func_expression*
440 func_expression() const
441 { return this->convert<const Func_expression, EXPRESSION_FUNC_REFERENCE>(); }
443 // If this is an expression which refers to an unknown name, return
444 // the Unknown_expression structure. Otherwise, return NULL.
447 { return this->convert<Unknown_expression, EXPRESSION_UNKNOWN_REFERENCE>(); }
449 const Unknown_expression*
450 unknown_expression() const
452 return this->convert<const Unknown_expression,
453 EXPRESSION_UNKNOWN_REFERENCE>();
456 // If this is an index expression, return the Index_expression
457 // structure. Otherwise, return NULL.
460 { return this->convert<Index_expression, EXPRESSION_INDEX>(); }
462 // If this is an expression which refers to indexing in a map,
463 // return the Map_index_expression structure. Otherwise, return
465 Map_index_expression*
466 map_index_expression()
467 { return this->convert<Map_index_expression, EXPRESSION_MAP_INDEX>(); }
469 // If this is a bound method expression, return the
470 // Bound_method_expression structure. Otherwise, return NULL.
471 Bound_method_expression*
472 bound_method_expression()
473 { return this->convert<Bound_method_expression, EXPRESSION_BOUND_METHOD>(); }
475 // If this is a reference to a field in a struct, return the
476 // Field_reference_expression structure. Otherwise, return NULL.
477 Field_reference_expression*
478 field_reference_expression()
480 return this->convert<Field_reference_expression,
481 EXPRESSION_FIELD_REFERENCE>();
484 // If this is a reference to a field in an interface, return the
485 // Interface_field_reference_expression structure. Otherwise,
487 Interface_field_reference_expression*
488 interface_field_reference_expression()
490 return this->convert<Interface_field_reference_expression,
491 EXPRESSION_INTERFACE_FIELD_REFERENCE>();
494 // If this is a type guard expression, return the
495 // Type_guard_expression structure. Otherwise, return NULL.
496 Type_guard_expression*
497 type_guard_expression()
498 { return this->convert<Type_guard_expression, EXPRESSION_TYPE_GUARD>(); }
500 // If this is a receive expression, return the Receive_expression
501 // structure. Otherwise, return NULL.
504 { return this->convert<Receive_expression, EXPRESSION_RECEIVE>(); }
506 // Return true if this is a composite literal.
508 is_composite_literal() const;
510 // Return true if this is a composite literal which is not constant.
512 is_nonconstant_composite_literal() const;
514 // Return true if this is a reference to a local variable.
516 is_local_variable() const;
518 // Traverse an expression.
520 traverse(Expression**, Traverse*);
522 // Traverse subexpressions of this expression.
524 traverse_subexpressions(Traverse*);
526 // Lower an expression. This is called immediately after parsing.
527 // FUNCTION is the function we are in; it will be NULL for an
528 // expression initializing a global variable. INSERTER may be used
529 // to insert statements before the statement or initializer
530 // containing this expression; it is normally used to create
531 // temporary variables. IOTA_VALUE is the value that we should give
532 // to any iota expressions. This function must resolve expressions
533 // which could not be fully parsed into their final form. It
534 // returns the same Expression or a new one.
536 lower(Gogo* gogo, Named_object* function, Statement_inserter* inserter,
538 { return this->do_lower(gogo, function, inserter, iota_value); }
540 // Determine the real type of an expression with abstract integer,
541 // floating point, or complex type. TYPE_CONTEXT describes the
544 determine_type(const Type_context*);
546 // Check types in an expression.
548 check_types(Gogo* gogo)
549 { this->do_check_types(gogo); }
551 // Determine the type when there is no context.
553 determine_type_no_context();
555 // Return the current type of the expression. This may be changed
556 // by determine_type.
559 { return this->do_type(); }
561 // Return a copy of an expression.
564 { return this->do_copy(); }
566 // Return whether the expression is addressable--something which may
567 // be used as the operand of the unary & operator.
569 is_addressable() const
570 { return this->do_is_addressable(); }
572 // Note that we are taking the address of this expression. ESCAPES
573 // is true if this address escapes the current function.
575 address_taken(bool escapes)
576 { this->do_address_taken(escapes); }
578 // Return whether this expression must be evaluated in order
579 // according to the order of evaluation rules. This is basically
580 // true of all expressions with side-effects.
582 must_eval_in_order() const
583 { return this->do_must_eval_in_order(); }
585 // Return the tree for this expression.
587 get_tree(Translate_context*);
589 // Return a tree handling any conversions which must be done during
592 convert_for_assignment(Translate_context*, Type* lhs_type, Type* rhs_type,
593 tree rhs_tree, source_location location);
595 // Return a tree converting a value of one interface type to another
596 // interface type. If FOR_TYPE_GUARD is true this is for a type
599 convert_interface_to_interface(Translate_context*, Type* lhs_type,
600 Type* rhs_type, tree rhs_tree,
601 bool for_type_guard, source_location);
603 // Return a tree implementing the comparison LHS_TREE OP RHS_TREE.
604 // TYPE is the type of both sides.
606 comparison_tree(Translate_context*, Operator op, Type* left_type,
607 tree left_tree, Type* right_type, tree right_tree,
610 // Return a tree for the multi-precision integer VAL in TYPE.
612 integer_constant_tree(mpz_t val, tree type);
614 // Return a tree for the floating point value VAL in TYPE.
616 float_constant_tree(mpfr_t val, tree type);
618 // Return a tree for the complex value REAL/IMAG in TYPE.
620 complex_constant_tree(mpfr_t real, mpfr_t imag, tree type);
622 // Export the expression. This is only used for constants. It will
623 // be used for things like values of named constants and sizes of
626 export_expression(Export* exp) const
627 { this->do_export(exp); }
629 // Import an expression.
631 import_expression(Import*);
633 // Return a tree which checks that VAL, of arbitrary integer type,
634 // is non-negative and is not more than the maximum value of
635 // BOUND_TYPE. If SOFAR is not NULL, it is or'red into the result.
636 // The return value may be NULL if SOFAR is NULL.
638 check_bounds(tree val, tree bound_type, tree sofar, source_location);
640 // Dump an expression to a dump constext.
642 dump_expression(Ast_dump_context*) const;
645 // May be implemented by child class: traverse the expressions.
647 do_traverse(Traverse*);
649 // Return a lowered expression.
651 do_lower(Gogo*, Named_object*, Statement_inserter*, int)
654 // Return whether this is a constant expression.
656 do_is_constant() const
659 // Return whether this is a constant expression of integral type,
660 // and set VAL to the value.
662 do_integer_constant_value(bool, mpz_t, Type**) const
665 // Return whether this is a constant expression of floating point
666 // type, and set VAL to the value.
668 do_float_constant_value(mpfr_t, Type**) const
671 // Return whether this is a constant expression of complex type, and
672 // set REAL and IMAGE to the value.
674 do_complex_constant_value(mpfr_t, mpfr_t, Type**) const
677 // Return whether this is a constant expression of string type, and
678 // set VAL to the value.
680 do_string_constant_value(std::string*) const
683 // Called by the parser if the value is being discarded.
685 do_discarding_value();
687 // Child class holds type.
691 // Child class implements determining type information.
693 do_determine_type(const Type_context*) = 0;
695 // Child class implements type checking if needed.
697 do_check_types(Gogo*)
700 // Child class implements copying.
704 // Child class implements whether the expression is addressable.
706 do_is_addressable() const
709 // Child class implements taking the address of an expression.
711 do_address_taken(bool)
714 // Child class implements whether this expression must be evaluated
717 do_must_eval_in_order() const
720 // Child class implements conversion to tree.
722 do_get_tree(Translate_context*) = 0;
724 // Child class implements export.
726 do_export(Export*) const;
728 // For children to call to warn about an unused value.
730 warn_about_unused_value();
732 // For children to call when they detect that they are in error.
736 // For children to call to report an error conveniently.
738 report_error(const char*);
740 // Child class implements dumping to a dump context.
742 do_dump_expression(Ast_dump_context*) const = 0;
745 // Convert to the desired statement classification, or return NULL.
746 // This is a controlled dynamic cast.
747 template<typename Expression_class,
748 Expression_classification expr_classification>
752 return (this->classification_ == expr_classification
753 ? static_cast<Expression_class*>(this)
757 template<typename Expression_class,
758 Expression_classification expr_classification>
759 const Expression_class*
762 return (this->classification_ == expr_classification
763 ? static_cast<const Expression_class*>(this)
768 convert_type_to_interface(Translate_context*, Type*, Type*, tree,
772 get_interface_type_descriptor(Translate_context*, Type*, tree,
776 convert_interface_to_type(Translate_context*, Type*, Type*, tree,
779 // The expression classification.
780 Expression_classification classification_;
781 // The location in the input file.
782 source_location location_;
785 // A list of Expressions.
787 class Expression_list
794 // Return whether the list is empty.
797 { return this->entries_.empty(); }
799 // Return the number of entries in the list.
802 { return this->entries_.size(); }
804 // Add an entry to the end of the list.
806 push_back(Expression* expr)
807 { this->entries_.push_back(expr); }
810 append(Expression_list* add)
811 { this->entries_.insert(this->entries_.end(), add->begin(), add->end()); }
813 // Reserve space in the list.
816 { this->entries_.reserve(size); }
818 // Traverse the expressions in the list.
826 // Return true if the list contains an error expression.
828 contains_error() const;
830 // Return the first and last elements.
833 { return this->entries_.front(); }
837 { return this->entries_.front(); }
841 { return this->entries_.back(); }
845 { return this->entries_.back(); }
849 typedef std::vector<Expression*>::iterator iterator;
850 typedef std::vector<Expression*>::const_iterator const_iterator;
854 { return this->entries_.begin(); }
858 { return this->entries_.begin(); }
862 { return this->entries_.end(); }
866 { return this->entries_.end(); }
871 { this->entries_.erase(p); }
874 std::vector<Expression*> entries_;
877 // An abstract base class for an expression which is only used by the
878 // parser, and is lowered in the lowering pass.
880 class Parser_expression : public Expression
883 Parser_expression(Expression_classification classification,
884 source_location location)
885 : Expression(classification, location)
890 do_lower(Gogo*, Named_object*, Statement_inserter*, int) = 0;
896 do_determine_type(const Type_context*)
897 { go_unreachable(); }
900 do_check_types(Gogo*)
901 { go_unreachable(); }
904 do_get_tree(Translate_context*)
905 { go_unreachable(); }
908 // An expression which is simply a variable.
910 class Var_expression : public Expression
913 Var_expression(Named_object* variable, source_location location)
914 : Expression(EXPRESSION_VAR_REFERENCE, location),
918 // Return the variable.
921 { return this->variable_; }
925 do_lower(Gogo*, Named_object*, Statement_inserter*, int);
931 do_determine_type(const Type_context*);
938 do_is_addressable() const
942 do_address_taken(bool);
945 do_get_tree(Translate_context*);
948 do_dump_expression(Ast_dump_context*) const;
951 // The variable we are referencing.
952 Named_object* variable_;
955 // A reference to a temporary variable.
957 class Temporary_reference_expression : public Expression
960 Temporary_reference_expression(Temporary_statement* statement,
961 source_location location)
962 : Expression(EXPRESSION_TEMPORARY_REFERENCE, location),
963 statement_(statement), is_lvalue_(false)
966 // Indicate that this reference appears on the left hand side of an
967 // assignment statement.
970 { this->is_lvalue_ = true; }
977 do_determine_type(const Type_context*)
982 { return make_temporary_reference(this->statement_, this->location()); }
985 do_is_addressable() const
989 do_address_taken(bool);
992 do_get_tree(Translate_context*);
995 do_dump_expression(Ast_dump_context*) const;
998 // The statement where the temporary variable is defined.
999 Temporary_statement* statement_;
1000 // Whether this reference appears on the left hand side of an
1001 // assignment statement.
1005 // A string expression.
1007 class String_expression : public Expression
1010 String_expression(const std::string& val, source_location location)
1011 : Expression(EXPRESSION_STRING, location),
1012 val_(val), type_(NULL)
1017 { return this->val_; }
1024 do_is_constant() const
1028 do_string_constant_value(std::string* val) const
1038 do_determine_type(const Type_context*);
1045 do_get_tree(Translate_context*);
1047 // Write string literal to a string dump.
1049 export_string(String_dump* exp, const String_expression* str);
1052 do_export(Export*) const;
1055 do_dump_expression(Ast_dump_context*) const;
1058 // The string value. This is immutable.
1059 const std::string val_;
1060 // The type as determined by context.
1064 // A binary expression.
1066 class Binary_expression : public Expression
1069 Binary_expression(Operator op, Expression* left, Expression* right,
1070 source_location location)
1071 : Expression(EXPRESSION_BINARY, location),
1072 op_(op), left_(left), right_(right)
1075 // Return the operator.
1078 { return this->op_; }
1080 // Return the left hand expression.
1083 { return this->left_; }
1085 // Return the right hand expression.
1088 { return this->right_; }
1090 // Apply binary opcode OP to LEFT_VAL and RIGHT_VAL, setting VAL.
1091 // LEFT_TYPE is the type of LEFT_VAL, RIGHT_TYPE is the type of
1092 // RIGHT_VAL; LEFT_TYPE and/or RIGHT_TYPE may be NULL. Return true
1093 // if this could be done, false if not.
1095 eval_integer(Operator op, Type* left_type, mpz_t left_val,
1096 Type* right_type, mpz_t right_val, source_location,
1099 // Apply binary opcode OP to LEFT_VAL and RIGHT_VAL, setting VAL.
1100 // Return true if this could be done, false if not.
1102 eval_float(Operator op, Type* left_type, mpfr_t left_val,
1103 Type* right_type, mpfr_t right_val, mpfr_t val,
1106 // Apply binary opcode OP to LEFT_REAL/LEFT_IMAG and
1107 // RIGHT_REAL/RIGHT_IMAG, setting REAL/IMAG. Return true if this
1108 // could be done, false if not.
1110 eval_complex(Operator op, Type* left_type, mpfr_t left_real,
1111 mpfr_t left_imag, Type* right_type, mpfr_t right_real,
1112 mpfr_t right_imag, mpfr_t real, mpfr_t imag, source_location);
1114 // Compare integer constants according to OP.
1116 compare_integer(Operator op, mpz_t left_val, mpz_t right_val);
1118 // Compare floating point constants according to OP.
1120 compare_float(Operator op, Type* type, mpfr_t left_val, mpfr_t right_val);
1122 // Compare complex constants according to OP.
1124 compare_complex(Operator op, Type* type, mpfr_t left_real, mpfr_t left_imag,
1125 mpfr_t right_val, mpfr_t right_imag);
1130 // Report an error if OP can not be applied to TYPE. Return whether
1133 check_operator_type(Operator op, Type* type, source_location);
1137 do_traverse(Traverse* traverse);
1140 do_lower(Gogo*, Named_object*, Statement_inserter*, int);
1143 do_is_constant() const
1144 { return this->left_->is_constant() && this->right_->is_constant(); }
1147 do_integer_constant_value(bool, mpz_t val, Type**) const;
1150 do_float_constant_value(mpfr_t val, Type**) const;
1153 do_complex_constant_value(mpfr_t real, mpfr_t imag, Type**) const;
1156 do_discarding_value();
1162 do_determine_type(const Type_context*);
1165 do_check_types(Gogo*);
1170 return Expression::make_binary(this->op_, this->left_->copy(),
1171 this->right_->copy(), this->location());
1175 do_get_tree(Translate_context*);
1178 do_export(Export*) const;
1181 do_dump_expression(Ast_dump_context*) const;
1184 // The binary operator to apply.
1186 // The left hand side operand.
1188 // The right hand side operand.
1192 // A call expression. The go statement needs to dig inside this.
1194 class Call_expression : public Expression
1197 Call_expression(Expression* fn, Expression_list* args, bool is_varargs,
1198 source_location location)
1199 : Expression(EXPRESSION_CALL, location),
1200 fn_(fn), args_(args), type_(NULL), results_(NULL), tree_(NULL),
1201 is_varargs_(is_varargs), varargs_are_lowered_(false),
1202 types_are_determined_(false), is_deferred_(false), issued_error_(false)
1205 // The function to call.
1208 { return this->fn_; }
1213 { return this->args_; }
1215 const Expression_list*
1217 { return this->args_; }
1219 // Get the function type.
1221 get_function_type() const;
1223 // Return the number of values this call will return.
1225 result_count() const;
1227 // Return the temporary variable which holds result I. This is only
1228 // valid after the expression has been lowered, and is only valid
1229 // for calls which return multiple results.
1230 Temporary_statement*
1231 result(size_t i) const;
1233 // Return whether this is a call to the predeclared function
1236 is_recover_call() const;
1238 // Set the argument for a call to recover.
1240 set_recover_arg(Expression*);
1242 // Whether the last argument is a varargs argument (f(a...)).
1245 { return this->is_varargs_; }
1247 // Whether this call is being deferred.
1250 { return this->is_deferred_; }
1252 // Note that the call is being deferred.
1255 { this->is_deferred_ = true; }
1257 // We have found an error with this call expression; return true if
1258 // we should report it.
1264 do_traverse(Traverse*);
1267 do_lower(Gogo*, Named_object*, Statement_inserter*, int);
1270 do_discarding_value()
1277 do_determine_type(const Type_context*);
1280 do_check_types(Gogo*);
1285 return Expression::make_call(this->fn_->copy(),
1286 (this->args_ == NULL
1288 : this->args_->copy()),
1289 this->is_varargs_, this->location());
1293 do_must_eval_in_order() const;
1296 do_get_tree(Translate_context*);
1299 do_is_recover_call() const;
1302 do_set_recover_arg(Expression*);
1304 // Let a builtin expression change the argument list.
1306 set_args(Expression_list* args)
1307 { this->args_ = args; }
1309 // Let a builtin expression lower varargs.
1311 lower_varargs(Gogo*, Named_object* function, Statement_inserter* inserter,
1312 Type* varargs_type, size_t param_count);
1314 // Let a builtin expression check whether types have been
1317 determining_types();
1320 do_dump_expression(Ast_dump_context*) const;
1324 check_argument_type(int, const Type*, const Type*, source_location, bool);
1327 bound_method_function(Translate_context*, Bound_method_expression*, tree*);
1330 interface_method_function(Translate_context*,
1331 Interface_field_reference_expression*,
1335 set_results(Translate_context*, tree);
1337 // The function to call.
1339 // The arguments to pass. This may be NULL if there are no
1341 Expression_list* args_;
1342 // The type of the expression, to avoid recomputing it.
1344 // The list of temporaries which will hold the results if the
1345 // function returns a tuple.
1346 std::vector<Temporary_statement*>* results_;
1347 // The tree for the call, used for a call which returns a tuple.
1349 // True if the last argument is a varargs argument (f(a...)).
1351 // True if varargs have already been lowered.
1352 bool varargs_are_lowered_;
1353 // True if types have been determined.
1354 bool types_are_determined_;
1355 // True if the call is an argument to a defer statement.
1357 // True if we reported an error about a mismatch between call
1358 // results and uses. This is to avoid producing multiple errors
1359 // when there are multiple Call_result_expressions.
1363 // An expression which represents a pointer to a function.
1365 class Func_expression : public Expression
1368 Func_expression(Named_object* function, Expression* closure,
1369 source_location location)
1370 : Expression(EXPRESSION_FUNC_REFERENCE, location),
1371 function_(function), closure_(closure)
1374 // Return the object associated with the function.
1376 named_object() const
1377 { return this->function_; }
1379 // Return the closure for this function. This will return NULL if
1380 // the function has no closure, which is the normal case.
1383 { return this->closure_; }
1385 // Return a tree for this function without evaluating the closure.
1387 get_tree_without_closure(Gogo*);
1391 do_traverse(Traverse*);
1397 do_determine_type(const Type_context*)
1399 if (this->closure_ != NULL)
1400 this->closure_->determine_type_no_context();
1406 return Expression::make_func_reference(this->function_,
1407 (this->closure_ == NULL
1409 : this->closure_->copy()),
1414 do_get_tree(Translate_context*);
1417 do_dump_expression(Ast_dump_context*) const;
1420 // The function itself.
1421 Named_object* function_;
1422 // A closure. This is normally NULL. For a nested function, it may
1423 // be a heap-allocated struct holding pointers to all the variables
1424 // referenced by this function and defined in enclosing functions.
1425 Expression* closure_;
1428 // A reference to an unknown name.
1430 class Unknown_expression : public Parser_expression
1433 Unknown_expression(Named_object* named_object, source_location location)
1434 : Parser_expression(EXPRESSION_UNKNOWN_REFERENCE, location),
1435 named_object_(named_object), is_composite_literal_key_(false)
1438 // The associated named object.
1440 named_object() const
1441 { return this->named_object_; }
1443 // The name of the identifier which was unknown.
1447 // Note that this expression is being used as the key in a composite
1448 // literal, so it may be OK if it is not resolved.
1450 set_is_composite_literal_key()
1451 { this->is_composite_literal_key_ = true; }
1453 // Note that this expression should no longer be treated as a
1454 // composite literal key.
1456 clear_is_composite_literal_key()
1457 { this->is_composite_literal_key_ = false; }
1461 do_lower(Gogo*, Named_object*, Statement_inserter*, int);
1465 { return new Unknown_expression(this->named_object_, this->location()); }
1468 do_dump_expression(Ast_dump_context*) const;
1471 // The unknown name.
1472 Named_object* named_object_;
1473 // True if this is the key in a composite literal.
1474 bool is_composite_literal_key_;
1477 // An index expression. This is lowered to an array index, a string
1478 // index, or a map index.
1480 class Index_expression : public Parser_expression
1483 Index_expression(Expression* left, Expression* start, Expression* end,
1484 source_location location)
1485 : Parser_expression(EXPRESSION_INDEX, location),
1486 left_(left), start_(start), end_(end), is_lvalue_(false)
1489 // Record that this expression is an lvalue.
1492 { this->is_lvalue_ = true; }
1494 // Dump an index expression, i.e. an expression of the form
1495 // expr[expr] or expr[expr:expr], to a dump context.
1497 dump_index_expression(Ast_dump_context*, const Expression* expr,
1498 const Expression* start, const Expression* end);
1502 do_traverse(Traverse*);
1505 do_lower(Gogo*, Named_object*, Statement_inserter*, int);
1510 return new Index_expression(this->left_->copy(), this->start_->copy(),
1513 : this->end_->copy()),
1518 do_dump_expression(Ast_dump_context*) const;
1521 // The expression being indexed.
1525 // The second index. This is NULL for an index, non-NULL for a
1528 // Whether this is being used as an l-value. We set this during the
1529 // parse because map index expressions need to know.
1533 // An index into a map.
1535 class Map_index_expression : public Expression
1538 Map_index_expression(Expression* map, Expression* index,
1539 source_location location)
1540 : Expression(EXPRESSION_MAP_INDEX, location),
1541 map_(map), index_(index), is_lvalue_(false),
1542 is_in_tuple_assignment_(false)
1548 { return this->map_; }
1552 { return this->map_; }
1554 // Return the index.
1557 { return this->index_; }
1561 { return this->index_; }
1563 // Get the type of the map being indexed.
1565 get_map_type() const;
1567 // Record that this map expression is an lvalue. The difference is
1568 // that an lvalue always inserts the key.
1571 { this->is_lvalue_ = true; }
1573 // Return whether this map expression occurs in an assignment to a
1576 is_in_tuple_assignment() const
1577 { return this->is_in_tuple_assignment_; }
1579 // Record that this map expression occurs in an assignment to a pair
1582 set_is_in_tuple_assignment()
1583 { this->is_in_tuple_assignment_ = true; }
1585 // Return a tree for the map index. This returns a tree which
1586 // evaluates to a pointer to a value in the map. If INSERT is true,
1587 // the key will be inserted if not present, and the value pointer
1588 // will be zero initialized. If INSERT is false, and the key is not
1589 // present in the map, the pointer will be NULL.
1591 get_value_pointer(Translate_context*, bool insert);
1595 do_traverse(Traverse*);
1601 do_determine_type(const Type_context*);
1604 do_check_types(Gogo*);
1609 return Expression::make_map_index(this->map_->copy(),
1610 this->index_->copy(),
1614 // A map index expression is an lvalue but it is not addressable.
1617 do_get_tree(Translate_context*);
1620 do_dump_expression(Ast_dump_context*) const;
1623 // The map we are looking into.
1627 // Whether this is an lvalue.
1629 // Whether this is in a tuple assignment to a pair of values.
1630 bool is_in_tuple_assignment_;
1633 // An expression which represents a method bound to its first
1636 class Bound_method_expression : public Expression
1639 Bound_method_expression(Expression* expr, Expression* method,
1640 source_location location)
1641 : Expression(EXPRESSION_BOUND_METHOD, location),
1642 expr_(expr), expr_type_(NULL), method_(method)
1645 // Return the object which is the first argument.
1648 { return this->expr_; }
1650 // Return the implicit type of the first argument. This will be
1651 // non-NULL when using a method from an anonymous field without
1652 // using an explicit stub.
1654 first_argument_type() const
1655 { return this->expr_type_; }
1657 // Return the reference to the method function.
1660 { return this->method_; }
1662 // Set the implicit type of the expression.
1664 set_first_argument_type(Type* type)
1665 { this->expr_type_ = type; }
1669 do_traverse(Traverse*);
1675 do_determine_type(const Type_context*);
1678 do_check_types(Gogo*);
1683 return new Bound_method_expression(this->expr_->copy(),
1684 this->method_->copy(),
1689 do_get_tree(Translate_context*);
1692 do_dump_expression(Ast_dump_context*) const;
1695 // The object used to find the method. This is passed to the method
1696 // as the first argument.
1698 // The implicit type of the object to pass to the method. This is
1699 // NULL in the normal case, non-NULL when using a method from an
1700 // anonymous field which does not require a stub.
1702 // The method itself. This is a Func_expression.
1703 Expression* method_;
1706 // A reference to a field in a struct.
1708 class Field_reference_expression : public Expression
1711 Field_reference_expression(Expression* expr, unsigned int field_index,
1712 source_location location)
1713 : Expression(EXPRESSION_FIELD_REFERENCE, location),
1714 expr_(expr), field_index_(field_index)
1717 // Return the struct expression.
1720 { return this->expr_; }
1722 // Return the field index.
1725 { return this->field_index_; }
1727 // Set the struct expression. This is used when parsing.
1729 set_struct_expression(Expression* expr)
1731 go_assert(this->expr_ == NULL);
1737 do_traverse(Traverse* traverse)
1738 { return Expression::traverse(&this->expr_, traverse); }
1744 do_determine_type(const Type_context*)
1745 { this->expr_->determine_type_no_context(); }
1748 do_check_types(Gogo*);
1753 return Expression::make_field_reference(this->expr_->copy(),
1759 do_is_addressable() const
1760 { return this->expr_->is_addressable(); }
1763 do_get_tree(Translate_context*);
1766 do_dump_expression(Ast_dump_context*) const;
1769 // The expression we are looking into. This should have a type of
1772 // The zero-based index of the field we are retrieving.
1773 unsigned int field_index_;
1776 // A reference to a field of an interface.
1778 class Interface_field_reference_expression : public Expression
1781 Interface_field_reference_expression(Expression* expr,
1782 const std::string& name,
1783 source_location location)
1784 : Expression(EXPRESSION_INTERFACE_FIELD_REFERENCE, location),
1785 expr_(expr), name_(name)
1788 // Return the expression for the interface object.
1791 { return this->expr_; }
1793 // Return the name of the method to call.
1796 { return this->name_; }
1798 // Return a tree for the pointer to the function to call, given a
1799 // tree for the expression.
1801 get_function_tree(Translate_context*, tree);
1803 // Return a tree for the first argument to pass to the interface
1804 // function, given a tree for the expression. This is the real
1805 // object associated with the interface object.
1807 get_underlying_object_tree(Translate_context*, tree);
1811 do_traverse(Traverse* traverse);
1817 do_determine_type(const Type_context*);
1820 do_check_types(Gogo*);
1825 return Expression::make_interface_field_reference(this->expr_->copy(),
1831 do_get_tree(Translate_context*);
1834 do_dump_expression(Ast_dump_context*) const;
1837 // The expression for the interface object. This should have a type
1838 // of interface or pointer to interface.
1840 // The field we are retrieving--the name of the method.
1844 // A type guard expression.
1846 class Type_guard_expression : public Expression
1849 Type_guard_expression(Expression* expr, Type* type, source_location location)
1850 : Expression(EXPRESSION_TYPE_GUARD, location),
1851 expr_(expr), type_(type)
1854 // Return the expression to convert.
1857 { return this->expr_; }
1859 // Return the type to which to convert.
1862 { return this->type_; }
1866 do_traverse(Traverse* traverse);
1870 { return this->type_; }
1873 do_determine_type(const Type_context*)
1874 { this->expr_->determine_type_no_context(); }
1877 do_check_types(Gogo*);
1882 return new Type_guard_expression(this->expr_->copy(), this->type_,
1887 do_get_tree(Translate_context*);
1890 do_dump_expression(Ast_dump_context*) const;
1893 // The expression to convert.
1895 // The type to which to convert.
1899 // A receive expression.
1901 class Receive_expression : public Expression
1904 Receive_expression(Expression* channel, source_location location)
1905 : Expression(EXPRESSION_RECEIVE, location),
1906 channel_(channel), for_select_(false)
1909 // Return the channel.
1912 { return this->channel_; }
1914 // Note that this is for a select statement.
1917 { this->for_select_ = true; }
1921 do_traverse(Traverse* traverse)
1922 { return Expression::traverse(&this->channel_, traverse); }
1925 do_discarding_value()
1932 do_determine_type(const Type_context*)
1933 { this->channel_->determine_type_no_context(); }
1936 do_check_types(Gogo*);
1941 return Expression::make_receive(this->channel_->copy(), this->location());
1945 do_must_eval_in_order() const
1949 do_get_tree(Translate_context*);
1952 do_dump_expression(Ast_dump_context*) const;
1955 // The channel from which we are receiving.
1956 Expression* channel_;
1957 // Whether this is for a select statement.
1961 #endif // !defined(GO_EXPRESSIONS_H)