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1.1 root 1: /* This file contains the definitions and documentation for the
2: tree codes used in the GNU C compiler.
1.1.1.4 root 3: Copyright (C) 1987, 1988, 1993 Free Software Foundation, Inc.
1.1 root 4:
5: This file is part of GNU CC.
6:
7: GNU CC is free software; you can redistribute it and/or modify
8: it under the terms of the GNU General Public License as published by
9: the Free Software Foundation; either version 2, or (at your option)
10: any later version.
11:
12: GNU CC is distributed in the hope that it will be useful,
13: but WITHOUT ANY WARRANTY; without even the implied warranty of
14: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15: GNU General Public License for more details.
16:
17: You should have received a copy of the GNU General Public License
18: along with GNU CC; see the file COPYING. If not, write to
19: the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
20:
21:
22: /* The third argument can be:
23: "x" for an exceptional code (fits no category).
24: "t" for a type object code.
1.1.1.2 root 25: "b" for a lexical block.
1.1 root 26: "c" for codes for constants.
27: "d" for codes for declarations (also serving as variable refs).
28: "r" for codes for references to storage.
29: "<" for codes for comparison expressions.
30: "1" for codes for unary arithmetic expressions.
31: "2" for codes for binary arithmetic expressions.
32: "s" for codes for expressions with inherent side effects.
33: "e" for codes for other kinds of expressions. */
34:
35: /* For `r', `e', `<', `1', `2', `s' and `x' nodes,
36: the 4th element is the number of argument slots to allocate.
37: This determines the size of the tree node object. */
38:
39: /* Any erroneous construct is parsed into a node of this type.
40: This type of node is accepted without complaint in all contexts
41: by later parsing activities, to avoid multiple error messages
42: for one error.
43: No fields in these nodes are used except the TREE_CODE. */
44: DEFTREECODE (ERROR_MARK, "error_mark", "x", 0)
45:
46: /* Used to represent a name (such as, in the DECL_NAME of a decl node).
47: Internally it looks like a STRING_CST node.
48: There is only one IDENTIFIER_NODE ever made for any particular name.
49: Use `get_identifier' to get it (or create it, the first time). */
50: DEFTREECODE (IDENTIFIER_NODE, "identifier_node", "x", -1)
51:
52: /* Used to hold information to identify an operator (or combination
53: of two operators) considered as a `noun' rather than a `verb'.
54: The first operand is encoded in the TREE_TYPE field. */
55: DEFTREECODE (OP_IDENTIFIER, "op_identifier", "x", 2)
56:
57: /* Has the TREE_VALUE and TREE_PURPOSE fields. */
58: /* These nodes are made into lists by chaining through the
59: TREE_CHAIN field. The elements of the list live in the
60: TREE_VALUE fields, while TREE_PURPOSE fields are occasionally
61: used as well to get the effect of Lisp association lists. */
62: DEFTREECODE (TREE_LIST, "tree_list", "x", 2)
63:
64: /* These nodes contain an array of tree nodes. */
65: DEFTREECODE (TREE_VEC, "tree_vec", "x", 2)
66:
67: /* A symbol binding block. These are arranged in a tree,
68: where the BLOCK_SUBBLOCKS field contains a chain of subblocks
69: chained through the BLOCK_CHAIN field.
70: BLOCK_SUPERCONTEXT points to the parent block.
1.1.1.2 root 71: For a block which represents the outermost scope of a function, it
72: points to the FUNCTION_DECL node.
1.1 root 73: BLOCK_VARS points to a chain of decl nodes.
74: BLOCK_TYPE_TAGS points to a chain of types which have their own names.
1.1.1.2 root 75: BLOCK_CHAIN points to the next BLOCK at the same level.
76: BLOCK_ABSTRACT_ORIGIN points to the original (abstract) tree node which
77: this block is an instance of, or else is NULL to indicate that this
78: block is not an instance of anything else. When non-NULL, the value
79: could either point to another BLOCK node or it could point to a
80: FUNCTION_DECL node (e.g. in the case of a block representing the
81: outermost scope of a particular inlining of a function).
82: BLOCK_ABSTRACT is non-zero if the block represents an abstract
83: instance of a block (i.e. one which is nested within an abstract
84: instance of a inline function. */
85: DEFTREECODE (BLOCK, "block", "b", 0)
1.1 root 86:
87: /* Each data type is represented by a tree node whose code is one of
88: the following: */
89: /* Each node that represents a data type has a component TYPE_SIZE
90: containing a tree that is an expression for the size in bits.
91: The TYPE_MODE contains the machine mode for values of this type.
92: The TYPE_POINTER_TO field contains a type for a pointer to this type,
93: or zero if no such has been created yet.
94: The TYPE_NEXT_VARIANT field is used to chain together types
95: that are variants made by type modifiers such as "const" and "volatile".
96: The TYPE_MAIN_VARIANT field, in any member of such a chain,
97: points to the start of the chain.
98: The TYPE_NONCOPIED_PARTS field is a list specifying which parts
99: of an object of this type should *not* be copied by assignment.
100: The TREE_PURPOSE of each element is the offset of the part
101: and the TREE_VALUE is the size in bits of the part.
102: The TYPE_NAME field contains info on the name used in the program
103: for this type (for GDB symbol table output). It is either a
104: TYPE_DECL node, for types that are typedefs, or an IDENTIFIER_NODE
105: in the case of structs, unions or enums that are known with a tag,
106: or zero for types that have no special name.
1.1.1.2 root 107: The TYPE_CONTEXT for any sort of type which could have a name or
108: which could have named members (e.g. tagged types in C/C++) will
109: point to the node which represents the scope of the given type, or
110: will be NULL_TREE if the type has "file scope". For most types, this
111: will point to a BLOCK node or a FUNCTION_DECL node, but it could also
112: point to a FUNCTION_TYPE node (for types whose scope is limited to the
1.1 root 113: formal parameter list of some function type specification) or it
1.1.1.3 root 114: could point to a RECORD_TYPE, UNION_TYPE or QUAL_UNION_TYPE node
115: (for C++ "member" types).
1.1 root 116: For non-tagged-types, TYPE_CONTEXT need not be set to anything in
1.1.1.2 root 117: particular, since any type which is of some type category (e.g.
118: an array type or a function type) which cannot either have a name
1.1.1.3 root 119: itself or have named members doesn't really have a "scope" per se.
120: The TREE_CHAIN field is used as a forward-references to names for
121: ENUMERAL_TYPE, RECORD_TYPE, UNION_TYPE, and QUAL_UNION_TYPE nodes;
122: see below. */
1.1 root 123:
124: DEFTREECODE (VOID_TYPE, "void_type", "t", 0) /* The void type in C */
125:
1.1.1.3 root 126: /* Integer types in all languages, including char in C.
127: Also used for sub-ranges of other discrete types.
128: Has components TYPE_MIN_VALUE, TYPE_MAX_VALUE (expressions, inclusive)
1.1 root 129: and TYPE_PRECISION (number of bits used by this type).
130: In the case of a subrange type in Pascal, the TREE_TYPE
1.1.1.3 root 131: of this will point at the supertype (another INTEGER_TYPE,
132: or an ENUMERAL_TYPE, CHAR_TYPE, or BOOLEAN_TYPE).
1.1 root 133: Otherwise, the TREE_TYPE is zero. */
134: DEFTREECODE (INTEGER_TYPE, "integer_type", "t", 0)
135:
136: /* C's float and double. Different floating types are distinguished
137: by machine mode and by the TYPE_SIZE and the TYPE_PRECISION. */
138: DEFTREECODE (REAL_TYPE, "real_type", "t", 0)
139:
140: /* Complex number types. The TREE_TYPE field is the data type
141: of the real and imaginary parts. */
142: DEFTREECODE (COMPLEX_TYPE, "complex_type", "t", 0)
143:
144: /* C enums. The type node looks just like an INTEGER_TYPE node.
145: The symbols for the values of the enum type are defined by
146: CONST_DECL nodes, but the type does not point to them;
1.1.1.3 root 147: however, the TYPE_VALUES is a list in which each element's TREE_PURPOSE
1.1 root 148: is a name and the TREE_VALUE is the value (an INTEGER_CST node). */
149: /* A forward reference `enum foo' when no enum named foo is defined yet
150: has zero (a null pointer) in its TYPE_SIZE. The tag name is in
151: the TYPE_NAME field. If the type is later defined, the normal
152: fields are filled in.
1.1.1.3 root 153: RECORD_TYPE, UNION_TYPE, and QUAL_UNION_TYPE forward refs are
154: treated similarly. */
1.1 root 155: DEFTREECODE (ENUMERAL_TYPE, "enumeral_type", "t", 0)
156:
157: /* Pascal's boolean type (true or false are the only values);
158: no special fields needed. */
159: DEFTREECODE (BOOLEAN_TYPE, "boolean_type", "t", 0)
160:
161: /* CHAR in Pascal; not used in C.
162: No special fields needed. */
163: DEFTREECODE (CHAR_TYPE, "char_type", "t", 0)
164:
165: /* All pointer-to-x types have code POINTER_TYPE.
166: The TREE_TYPE points to the node for the type pointed to. */
167: DEFTREECODE (POINTER_TYPE, "pointer_type", "t", 0)
168:
169: /* An offset is a pointer relative to an object.
170: The TREE_TYPE field is the type of the object at the offset.
171: The TYPE_OFFSET_BASETYPE points to the node for the type of object
172: that the offset is relative to. */
173: DEFTREECODE (OFFSET_TYPE, "offset_type", "t", 0)
174:
175: /* A reference is like a pointer except that it is coerced
176: automatically to the value it points to. Used in C++. */
177: DEFTREECODE (REFERENCE_TYPE, "reference_type", "t", 0)
178:
179: /* METHOD_TYPE is the type of a function which takes an extra first
180: argument for "self", which is not present in the declared argument list.
181: The TREE_TYPE is the return type of the method. The TYPE_METHOD_BASETYPE
182: is the type of "self". TYPE_ARG_TYPES is the real argument list, which
183: includes the hidden argument for "self". */
184: DEFTREECODE (METHOD_TYPE, "method_type", "t", 0)
185:
186: /* Used for Pascal; details not determined right now. */
187: DEFTREECODE (FILE_TYPE, "file_type", "t", 0)
188:
189: /* Types of arrays. Special fields:
190: TREE_TYPE Type of an array element.
191: TYPE_DOMAIN Type to index by.
192: Its range of values specifies the array length.
193: TYPE_SEP Expression for units from one elt to the next.
194: TYPE_SEP_UNIT Number of bits in a unit for previous.
195: The field TYPE_POINTER_TO (TREE_TYPE (array_type)) is always nonzero
1.1.1.5 ! root 196: and holds the type to coerce a value of that array type to in C.
! 197: TYPE_STRING_FLAG indicates a string (in contrast to an array of chars)
! 198: in languages (such as Chill) that make a distinction. */
1.1 root 199: /* Array types in C or Pascal */
200: DEFTREECODE (ARRAY_TYPE, "array_type", "t", 0)
201:
202: /* Types of sets for Pascal. Special fields are the same as
203: in an array type. The target type is always a boolean type. */
204: DEFTREECODE (SET_TYPE, "set_type", "t", 0)
205:
206: /* Struct in C, or record in Pascal. */
207: /* Special fields:
208: TYPE_FIELDS chain of FIELD_DECLs for the fields of the struct.
209: A few may need to be added for Pascal. */
210: /* See the comment above, before ENUMERAL_TYPE, for how
211: forward references to struct tags are handled in C. */
212: DEFTREECODE (RECORD_TYPE, "record_type", "t", 0)
213:
214: /* Union in C. Like a struct, except that the offsets of the fields
215: will all be zero. */
216: /* See the comment above, before ENUMERAL_TYPE, for how
217: forward references to union tags are handled in C. */
218: DEFTREECODE (UNION_TYPE, "union_type", "t", 0) /* C union type */
219:
1.1.1.3 root 220: /* Similar to UNION_TYPE, except that the expressions in DECL_QUALIFIER
221: in each FIELD_DECL determine what the union contains. The first
222: field whose DECL_QUALIFIER expression is true is deemed to occupy
223: the union. */
224: DEFTREECODE (QUAL_UNION_TYPE, "qual_union_type", "t", 0)
225:
1.1 root 226: /* Type of functions. Special fields:
227: TREE_TYPE type of value returned.
228: TYPE_ARG_TYPES list of types of arguments expected.
229: this list is made of TREE_LIST nodes.
230: Types of "Procedures" in languages where they are different from functions
231: have code FUNCTION_TYPE also, but then TREE_TYPE is zero or void type. */
232: DEFTREECODE (FUNCTION_TYPE, "function_type", "t", 0)
233:
234: /* This is a language-specific kind of type.
235: Its meaning is defined by the language front end.
236: layout_type does not know how to lay this out,
237: so the front-end must do so manually. */
238: DEFTREECODE (LANG_TYPE, "lang_type", "t", 0)
239:
240: /* Expressions */
241:
242: /* First, the constants. */
243:
244: /* Contents are in TREE_INT_CST_LOW and TREE_INT_CST_HIGH fields,
245: 32 bits each, giving us a 64 bit constant capability.
246: Note: constants of type char in Pascal are INTEGER_CST,
247: and so are pointer constants such as nil in Pascal or NULL in C.
248: `(int *) 1' in C also results in an INTEGER_CST. */
249: DEFTREECODE (INTEGER_CST, "integer_cst", "c", 2)
250:
251: /* Contents are in TREE_REAL_CST field. Also there is TREE_CST_RTL. */
252: DEFTREECODE (REAL_CST, "real_cst", "c", 3)
253:
254: /* Contents are in TREE_REALPART and TREE_IMAGPART fields,
255: whose contents are other constant nodes.
256: Also there is TREE_CST_RTL. */
257: DEFTREECODE (COMPLEX_CST, "complex_cst", "c", 3)
258:
259: /* Contents are TREE_STRING_LENGTH and TREE_STRING_POINTER fields.
260: Also there is TREE_CST_RTL. */
261: DEFTREECODE (STRING_CST, "string_cst", "c", 3)
262:
263: /* Declarations. All references to names are represented as ..._DECL nodes.
264: The decls in one binding context are chained through the TREE_CHAIN field.
265: Each DECL has a DECL_NAME field which contains an IDENTIFIER_NODE.
266: (Some decls, most often labels, may have zero as the DECL_NAME).
267: DECL_CONTEXT points to the node representing the context in which
268: this declaration has its scope. For FIELD_DECLs, this is the
1.1.1.3 root 269: RECORD_TYPE, UNION_TYPE, or QUAL_UNION_TYPE node that the field
270: is a member of. For VAR_DECL, PARM_DECL, FUNCTION_DECL, LABEL_DECL,
271: and CONST_DECL nodes, this points to the FUNCTION_DECL for the
272: containing function, or else yields NULL_TREE if the given decl
273: has "file scope".
1.1.1.2 root 274: DECL_ABSTRACT_ORIGIN, if non-NULL, points to the original (abstract)
275: ..._DECL node of which this decl is an (inlined or template expanded)
276: instance.
1.1 root 277: The TREE_TYPE field holds the data type of the object, when relevant.
278: LABEL_DECLs have no data type. For TYPE_DECL, the TREE_TYPE field
279: contents are the type whose name is being declared.
280: The DECL_ALIGN, DECL_SIZE,
281: and DECL_MODE fields exist in decl nodes just as in type nodes.
282: They are unused in LABEL_DECL, TYPE_DECL and CONST_DECL nodes.
283:
284: DECL_OFFSET holds an integer number of bits offset for the location.
285: DECL_VOFFSET holds an expression for a variable offset; it is
286: to be multiplied by DECL_VOFFSET_UNIT (an integer).
287: These fields are relevant only in FIELD_DECLs and PARM_DECLs.
288:
289: DECL_INITIAL holds the value to initialize a variable to,
290: or the value of a constant. For a function, it holds the body
291: (a node of type BLOCK representing the function's binding contour
292: and whose body contains the function's statements.) For a LABEL_DECL
293: in C, it is a flag, nonzero if the label's definition has been seen.
294:
295: PARM_DECLs use a special field:
296: DECL_ARG_TYPE is the type in which the argument is actually
297: passed, which may be different from its type within the function.
298:
299: FUNCTION_DECLs use four special fields:
300: DECL_ARGUMENTS holds a chain of PARM_DECL nodes for the arguments.
301: DECL_RESULT holds a RESULT_DECL node for the value of a function,
302: or it is 0 for a function that returns no value.
303: (C functions returning void have zero here.)
304: DECL_RESULT_TYPE holds the type in which the result is actually
305: returned. This is usually the same as the type of DECL_RESULT,
306: but (1) it may be a wider integer type and
307: (2) it remains valid, for the sake of inlining, even after the
308: function's compilation is done.
309: DECL_FUNCTION_CODE is a code number that is nonzero for
310: built-in functions. Its value is an enum built_in_function
311: that says which built-in function it is.
312:
313: DECL_SOURCE_FILE holds a filename string and DECL_SOURCE_LINE
314: holds a line number. In some cases these can be the location of
1.1.1.2 root 315: a reference, if no definition has been seen.
316:
317: DECL_ABSTRACT is non-zero if the decl represents an abstract instance
318: of a decl (i.e. one which is nested within an abstract instance of a
319: inline function. */
1.1 root 320:
321: DEFTREECODE (FUNCTION_DECL, "function_decl", "d", 0)
322: DEFTREECODE (LABEL_DECL, "label_decl", "d", 0)
323: DEFTREECODE (CONST_DECL, "const_decl", "d", 0)
324: DEFTREECODE (TYPE_DECL, "type_decl", "d", 0)
325: DEFTREECODE (VAR_DECL, "var_decl", "d", 0)
326: DEFTREECODE (PARM_DECL, "parm_decl", "d", 0)
327: DEFTREECODE (RESULT_DECL, "result_decl", "d", 0)
328: DEFTREECODE (FIELD_DECL, "field_decl", "d", 0)
329:
330: /* References to storage. */
331:
332: /* Value is structure or union component.
333: Operand 0 is the structure or union (an expression);
334: operand 1 is the field (a node of type FIELD_DECL). */
335: DEFTREECODE (COMPONENT_REF, "component_ref", "r", 2)
336:
337: /* Reference to a group of bits within an object. Similar to COMPONENT_REF
338: except the position is given explicitly rather than via a FIELD_DECL.
339: Operand 0 is the structure or union expression;
340: operand 1 is a tree giving the number of bits being referenced;
341: operand 2 is a tree giving the position of the first referenced bit.
342: The field can be either a signed or unsigned field;
343: TREE_UNSIGNED says which. */
344: DEFTREECODE (BIT_FIELD_REF, "bit_field_ref", "r", 3)
345:
346: /* C unary `*' or Pascal `^'. One operand, an expression for a pointer. */
347: DEFTREECODE (INDIRECT_REF, "indirect_ref", "r", 1)
348:
349: /* Reference to the contents of an offset
350: (a value whose type is an OFFSET_TYPE).
351: Operand 0 is the object within which the offset is taken.
352: Operand 1 is the offset. */
353: DEFTREECODE (OFFSET_REF, "offset_ref", "r", 2)
354:
355: /* Pascal `^` on a file. One operand, an expression for the file. */
356: DEFTREECODE (BUFFER_REF, "buffer_ref", "r", 1)
357:
358: /* Array indexing in languages other than C.
359: Operand 0 is the array; operand 1 is a list of indices
360: stored as a chain of TREE_LIST nodes. */
361: DEFTREECODE (ARRAY_REF, "array_ref", "r", 2)
362:
363: /* Constructor: return an aggregate value made from specified components.
364: In C, this is used only for structure and array initializers.
365: The first "operand" is really a pointer to the RTL,
366: for constant constructors only.
367: The second operand is a list of component values
368: made out of a chain of TREE_LIST nodes. */
369: DEFTREECODE (CONSTRUCTOR, "constructor", "e", 2)
370:
371: /* The expression types are mostly straightforward,
372: with the fourth argument of DEFTREECODE saying
373: how many operands there are.
374: Unless otherwise specified, the operands are expressions. */
375:
376: /* Contains two expressions to compute, one followed by the other.
377: the first value is ignored. The second one's value is used. */
378: DEFTREECODE (COMPOUND_EXPR, "compound_expr", "e", 2)
379:
380: /* Assignment expression. Operand 0 is the what to set; 1, the new value. */
381: DEFTREECODE (MODIFY_EXPR, "modify_expr", "e", 2)
382:
383: /* Initialization expression. Operand 0 is the variable to initialize;
384: Operand 1 is the initializer. */
385: DEFTREECODE (INIT_EXPR, "init_expr", "e", 2)
386:
387: /* For TARGET_EXPR, operand 0 is the target of an initialization,
388: operand 1 is the initializer for the target,
389: and operand 2 is the cleanup for this node, if any. */
390: DEFTREECODE (TARGET_EXPR, "target_expr", "e", 3)
391:
392: /* Conditional expression ( ... ? ... : ... in C).
393: Operand 0 is the condition.
394: Operand 1 is the then-value.
395: Operand 2 is the else-value. */
396: DEFTREECODE (COND_EXPR, "cond_expr", "e", 3)
397:
398: /* Declare local variables, including making RTL and allocating space.
399: Operand 0 is a chain of VAR_DECL nodes for the variables.
400: Operand 1 is the body, the expression to be computed using
401: the variables. The value of operand 1 becomes that of the BIND_EXPR.
402: Operand 2 is the BLOCK that corresponds to these bindings
403: for debugging purposes. If this BIND_EXPR is actually expanded,
404: that sets the TREE_USED flag in the BLOCK.
405:
406: The BIND_EXPR is not responsible for informing parsers
407: about these variables. If the body is coming from the input file,
408: then the code that creates the BIND_EXPR is also responsible for
409: informing the parser of the variables.
410:
411: If the BIND_EXPR is ever expanded, its TREE_USED flag is set.
412: This tells the code for debugging symbol tables not to ignore the BIND_EXPR.
413: If the BIND_EXPR should be output for debugging but will not be expanded,
414: set the TREE_USED flag by hand.
415:
416: In order for the BIND_EXPR to be known at all, the code that creates it
417: must also install it as a subblock in the tree of BLOCK
418: nodes for the function. */
419: DEFTREECODE (BIND_EXPR, "bind_expr", "e", 3)
420:
421: /* Function call. Operand 0 is the function.
422: Operand 1 is the argument list, a list of expressions
423: made out of a chain of TREE_LIST nodes.
424: There is no operand 2. That slot is used for the
425: CALL_EXPR_RTL macro (see preexpand_calls). */
426: DEFTREECODE (CALL_EXPR, "call_expr", "e", 3)
427:
428: /* Call a method. Operand 0 is the method, whose type is a METHOD_TYPE.
429: Operand 1 is the expression for "self".
430: Operand 2 is the list of explicit arguments. */
431: DEFTREECODE (METHOD_CALL_EXPR, "method_call_expr", "e", 4)
432:
433: /* Specify a value to compute along with its corresponding cleanup.
434: Operand 0 argument is an expression whose value needs a cleanup.
435: Operand 1 is an RTL_EXPR which will eventually represent that value.
436: Operand 2 is the cleanup expression for the object.
437: The RTL_EXPR is used in this expression, which is how the expression
438: manages to act on the proper value.
1.1.1.5 ! root 439: The cleanup is executed by the first enclosing CLEANUP_POINT_EXPR, if
! 440: it exists, otherwise it is the responsibility of the caller to manually
! 441: call expand_cleanups_to, as needed. */
1.1 root 442: DEFTREECODE (WITH_CLEANUP_EXPR, "with_cleanup_expr", "e", 3)
443:
1.1.1.5 ! root 444: /* Specify a cleanup point.
! 445: Operand 0 is the expression that has cleanups that we want ensure are
! 446: cleaned up. */
! 447: DEFTREECODE (CLEANUP_POINT_EXPR, "cleanup_point_expr", "e", 1)
! 448:
1.1.1.4 root 449: /* The following two codes are used in languages that have types where
450: the position and/or sizes of fields vary from object to object of the
451: same type, i.e., where some other field in the object contains a value
452: that is used in the computation of another field's offset or size.
453:
454: For example, a record type with a discriminant in Ada is such a type.
455: This mechanism is also used to create "fat pointers" for unconstrained
456: array types in Ada; the fat pointer is a structure one of whose fields is
457: a pointer to the actual array type and the other field is a pointer to a
458: template, which is a structure containing the bounds of the array. The
459: bounds in the type pointed to by the first field in the fat pointer refer
460: to the values in the template.
461:
462: These "self-references" are doing using a PLACEHOLDER_EXPR. This is a
463: node that will later be replaced with the object being referenced. Its type
464: is that of the object and selects which object to use from a chain of
465: references (see below).
466:
467: When we wish to evaluate a size or offset, we check it is contains a
468: placeholder. If it does, we construct a WITH_RECORD_EXPR that contains
469: both the expression we wish to evaluate and an expression within which the
470: object may be found. The latter expression is the object itself in
471: the simple case of an Ada record with discriminant, but it can be the
472: array in the case of an unconstrained array.
473:
474: In the latter case, we need the fat pointer, because the bounds of the
475: array can only be accessed from it. However, we rely here on the fact that
476: the expression for the array contains the dereference of the fat pointer
477: that obtained the array pointer.
478:
479: Accordingly, when looking for the object to substitute in place of
480: a PLACEHOLDER_EXPR, we look down the first operand of the expression
481: passed as the second operand to WITH_RECORD_EXPR until we find something
482: of the desired type or reach a constant. */
483:
484: /* Denotes a record to later be supplied with a WITH_RECORD_EXPR when
485: evaluating this expression. The type of this expression is used to
486: find the record to replace it. */
487: DEFTREECODE (PLACEHOLDER_EXPR, "placeholder_expr", "x", 0)
488:
489: /* Provide an expression that references a record to be used in place
490: of a PLACEHOLDER_EXPR. The record to be used is the record within
491: operand 1 that has the same type as the PLACEHOLDER_EXPR in
492: operand 0. */
493: DEFTREECODE (WITH_RECORD_EXPR, "with_record_expr", "e", 2)
494:
1.1 root 495: /* Simple arithmetic. Operands must have the same machine mode
496: and the value shares that mode. */
497: DEFTREECODE (PLUS_EXPR, "plus_expr", "2", 2)
498: DEFTREECODE (MINUS_EXPR, "minus_expr", "2", 2)
499: DEFTREECODE (MULT_EXPR, "mult_expr", "2", 2)
500:
501: /* Division for integer result that rounds the quotient toward zero. */
502: /* Operands must have the same machine mode.
503: In principle they may be real, but that is not currently supported.
504: The result is always fixed point, and it has the same type as the
505: operands if they are fixed point. */
506: DEFTREECODE (TRUNC_DIV_EXPR, "trunc_div_expr", "2", 2)
507:
508: /* Division for integer result that rounds the quotient toward infinity. */
509: DEFTREECODE (CEIL_DIV_EXPR, "ceil_div_expr", "2", 2)
510:
511: /* Division for integer result that rounds toward minus infinity. */
512: DEFTREECODE (FLOOR_DIV_EXPR, "floor_div_expr", "2", 2)
513:
514: /* Division for integer result that rounds toward nearest integer. */
515: DEFTREECODE (ROUND_DIV_EXPR, "round_div_expr", "2", 2)
516:
517: /* Four kinds of remainder that go with the four kinds of division. */
518: DEFTREECODE (TRUNC_MOD_EXPR, "trunc_mod_expr", "2", 2)
519: DEFTREECODE (CEIL_MOD_EXPR, "ceil_mod_expr", "2", 2)
520: DEFTREECODE (FLOOR_MOD_EXPR, "floor_mod_expr", "2", 2)
521: DEFTREECODE (ROUND_MOD_EXPR, "round_mod_expr", "2", 2)
522:
523: /* Division for real result. The two operands must have the same type.
524: In principle they could be integers, but currently only real
525: operands are supported. The result must have the same type
526: as the operands. */
527: DEFTREECODE (RDIV_EXPR, "rdiv_expr", "2", 2)
528:
529: /* Division which is not supposed to need rounding.
530: Used for pointer subtraction in C. */
531: DEFTREECODE (EXACT_DIV_EXPR, "exact_div_expr", "2", 2)
532:
533: /* Conversion of real to fixed point: four ways to round,
534: like the four ways to divide.
535: CONVERT_EXPR can also be used to convert a real to an integer,
536: and that is what is used in languages that do not have ways of
537: specifying which of these is wanted. Maybe these are not needed. */
538: DEFTREECODE (FIX_TRUNC_EXPR, "fix_trunc_expr", "1", 1)
539: DEFTREECODE (FIX_CEIL_EXPR, "fix_ceil_expr", "1", 1)
540: DEFTREECODE (FIX_FLOOR_EXPR, "fix_floor_expr", "1", 1)
541: DEFTREECODE (FIX_ROUND_EXPR, "fix_round_expr", "1", 1)
542:
543: /* Conversion of an integer to a real. */
544: DEFTREECODE (FLOAT_EXPR, "float_expr", "1", 1)
545:
546: /* Exponentiation. Operands may have any types;
547: constraints on value type are not known yet. */
548: DEFTREECODE (EXPON_EXPR, "expon_expr", "2", 2)
549:
550: /* Unary negation. Value has same type as operand. */
551: DEFTREECODE (NEGATE_EXPR, "negate_expr", "1", 1)
552:
553: DEFTREECODE (MIN_EXPR, "min_expr", "2", 2)
554: DEFTREECODE (MAX_EXPR, "max_expr", "2", 2)
555: DEFTREECODE (ABS_EXPR, "abs_expr", "1", 1)
556: DEFTREECODE (FFS_EXPR, "ffs_expr", "1", 1)
557:
558: /* Shift operations for shift and rotate.
559: Shift is supposed to mean logical shift if done on an
560: unsigned type, arithmetic shift on a signed type.
561: The second operand is the number of bits to
562: shift by, and must always have mode SImode.
563: The result has the same mode as the first operand. */
564: DEFTREECODE (LSHIFT_EXPR, "alshift_expr", "2", 2)
565: DEFTREECODE (RSHIFT_EXPR, "arshift_expr", "2", 2)
566: DEFTREECODE (LROTATE_EXPR, "lrotate_expr", "2", 2)
567: DEFTREECODE (RROTATE_EXPR, "rrotate_expr", "2", 2)
568:
569: /* Bitwise operations. Operands have same mode as result. */
570: DEFTREECODE (BIT_IOR_EXPR, "bit_ior_expr", "2", 2)
571: DEFTREECODE (BIT_XOR_EXPR, "bit_xor_expr", "2", 2)
572: DEFTREECODE (BIT_AND_EXPR, "bit_and_expr", "2", 2)
573: DEFTREECODE (BIT_ANDTC_EXPR, "bit_andtc_expr", "2", 2)
574: DEFTREECODE (BIT_NOT_EXPR, "bit_not_expr", "1", 1)
575:
576: /* Combination of boolean values or of integers considered only
577: as zero or nonzero. ANDIF and ORIF allow the second operand
578: not to be computed if the value of the expression is determined
1.1.1.3 root 579: from the first operand. AND, OR, and XOR always compute the second
1.1 root 580: operand whether its value is needed or not (for side effects). */
581: DEFTREECODE (TRUTH_ANDIF_EXPR, "truth_andif_expr", "e", 2)
582: DEFTREECODE (TRUTH_ORIF_EXPR, "truth_orif_expr", "e", 2)
1.1.1.4 root 583: DEFTREECODE (TRUTH_AND_EXPR, "truth_and_expr", "e", 2)
584: DEFTREECODE (TRUTH_OR_EXPR, "truth_or_expr", "e", 2)
585: DEFTREECODE (TRUTH_XOR_EXPR, "truth_xor_expr", "e", 2)
1.1 root 586: DEFTREECODE (TRUTH_NOT_EXPR, "truth_not_expr", "e", 1)
587:
588: /* Relational operators.
589: `EQ_EXPR' and `NE_EXPR' are allowed for any types.
590: The others are allowed only for integer (or pointer or enumeral)
591: or real types.
592: In all cases the operands will have the same type,
593: and the value is always the type used by the language for booleans. */
594: DEFTREECODE (LT_EXPR, "lt_expr", "<", 2)
595: DEFTREECODE (LE_EXPR, "le_expr", "<", 2)
596: DEFTREECODE (GT_EXPR, "gt_expr", "<", 2)
597: DEFTREECODE (GE_EXPR, "ge_expr", "<", 2)
598: DEFTREECODE (EQ_EXPR, "eq_expr", "<", 2)
599: DEFTREECODE (NE_EXPR, "ne_expr", "<", 2)
600:
601: /* Operations for Pascal sets. Not used now. */
602: DEFTREECODE (IN_EXPR, "in_expr", "2", 2)
603: DEFTREECODE (SET_LE_EXPR, "set_le_expr", "<", 2)
604: DEFTREECODE (CARD_EXPR, "card_expr", "1", 1)
605: DEFTREECODE (RANGE_EXPR, "range_expr", "2", 2)
606:
607: /* Represents a conversion of type of a value.
608: All conversions, including implicit ones, must be
609: represented by CONVERT_EXPR nodes. */
610: DEFTREECODE (CONVERT_EXPR, "convert_expr", "1", 1)
611:
612: /* Represents a conversion expected to require no code to be generated. */
613: DEFTREECODE (NOP_EXPR, "nop_expr", "1", 1)
614:
615: /* Value is same as argument, but guaranteed not an lvalue. */
616: DEFTREECODE (NON_LVALUE_EXPR, "non_lvalue_expr", "1", 1)
617:
618: /* Represents something we computed once and will use multiple times.
619: First operand is that expression. Second is the function decl
620: in which the SAVE_EXPR was created. The third operand is the RTL,
621: nonzero only after the expression has been computed. */
622: DEFTREECODE (SAVE_EXPR, "save_expr", "e", 3)
623:
624: /* Represents something whose RTL has already been expanded
625: as a sequence which should be emitted when this expression is expanded.
626: The first operand is the RTL to emit. It is the first of a chain of insns.
627: The second is the RTL expression for the result. */
628: DEFTREECODE (RTL_EXPR, "rtl_expr", "e", 2)
629:
630: /* & in C. Value is the address at which the operand's value resides.
631: Operand may have any mode. Result mode is Pmode. */
632: DEFTREECODE (ADDR_EXPR, "addr_expr", "e", 1)
633:
634: /* Non-lvalue reference or pointer to an object. */
635: DEFTREECODE (REFERENCE_EXPR, "reference_expr", "e", 1)
636:
637: /* Operand is a function constant; result is a function variable value
638: of typeEPmode. Used only for languages that need static chains. */
639: DEFTREECODE (ENTRY_VALUE_EXPR, "entry_value_expr", "e", 1)
640:
641: /* Given two real or integer operands of the same type,
642: returns a complex value of the corresponding complex type. */
643: DEFTREECODE (COMPLEX_EXPR, "complex_expr", "2", 2)
644:
645: /* Complex conjugate of operand. Used only on complex types.
646: The value has the same type as the operand. */
647: DEFTREECODE (CONJ_EXPR, "conj_expr", "1", 1)
648:
649: /* Used only on an operand of complex type, these return
650: a value of the corresponding component type. */
651: DEFTREECODE (REALPART_EXPR, "realpart_expr", "1", 1)
652: DEFTREECODE (IMAGPART_EXPR, "imagpart_expr", "1", 1)
653:
654: /* Nodes for ++ and -- in C.
655: The second arg is how much to increment or decrement by.
656: For a pointer, it would be the size of the object pointed to. */
657: DEFTREECODE (PREDECREMENT_EXPR, "predecrement_expr", "e", 2)
658: DEFTREECODE (PREINCREMENT_EXPR, "preincrement_expr", "e", 2)
659: DEFTREECODE (POSTDECREMENT_EXPR, "postdecrement_expr", "e", 2)
660: DEFTREECODE (POSTINCREMENT_EXPR, "postincrement_expr", "e", 2)
661:
662: /* These types of expressions have no useful value,
663: and always have side effects. */
664:
665: /* A label definition, encapsulated as a statement.
666: Operand 0 is the LABEL_DECL node for the label that appears here.
667: The type should be void and the value should be ignored. */
668: DEFTREECODE (LABEL_EXPR, "label_expr", "s", 1)
669:
670: /* GOTO. Operand 0 is a LABEL_DECL node.
671: The type should be void and the value should be ignored. */
672: DEFTREECODE (GOTO_EXPR, "goto_expr", "s", 1)
673:
674: /* RETURN. Evaluates operand 0, then returns from the current function.
675: Presumably that operand is an assignment that stores into the
676: RESULT_DECL that hold the value to be returned.
677: The operand may be null.
678: The type should be void and the value should be ignored. */
679: DEFTREECODE (RETURN_EXPR, "return_expr", "s", 1)
680:
681: /* Exit the inner most loop conditionally. Operand 0 is the condition.
682: The type should be void and the value should be ignored. */
683: DEFTREECODE (EXIT_EXPR, "exit_expr", "s", 1)
684:
685: /* A loop. Operand 0 is the body of the loop.
686: It must contain an EXIT_EXPR or is an infinite loop.
687: The type should be void and the value should be ignored. */
688: DEFTREECODE (LOOP_EXPR, "loop_expr", "s", 1)
689:
690: /*
691: Local variables:
692: mode:c
693: version-control: t
694: End:
695: */
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