1/* The lang_hooks data structure.
2   Copyright 2001, 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
3
4This file is part of GCC.
5
6GCC is free software; you can redistribute it and/or modify
7it under the terms of the GNU General Public License as published by
8the Free Software Foundation; either version 2, or (at your option)
9any later version.
10
11GCC is distributed in the hope that it will be useful,
12but WITHOUT ANY WARRANTY; without even the implied warranty of
13MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14GNU General Public License for more details.
15
16You should have received a copy of the GNU General Public License
17along with GCC; see the file COPYING.  If not, write to
18the Free Software Foundation, 51 Franklin Street, Fifth Floor,
19Boston, MA 02110-1301, USA.  */
20
21#ifndef GCC_LANG_HOOKS_H
22#define GCC_LANG_HOOKS_H
23
24/* This file should be #include-d after tree.h.  */
25
26struct diagnostic_context;
27
28struct gimplify_omp_ctx;
29
30/* A print hook for print_tree ().  */
31typedef void (*lang_print_tree_hook) (FILE *, tree, int indent);
32
33/* The following hooks are documented in langhooks.c.  Must not be
34   NULL.  */
35
36struct lang_hooks_for_tree_inlining
37{
38  tree (*walk_subtrees) (tree *, int *,
39			 tree (*) (tree *, int *, void *),
40			 void *, struct pointer_set_t*);
41  int (*cannot_inline_tree_fn) (tree *);
42  int (*disregard_inline_limits) (tree);
43  tree (*add_pending_fn_decls) (void *, tree);
44  int (*auto_var_in_fn_p) (tree, tree);
45  int (*anon_aggr_type_p) (tree);
46  bool (*var_mod_type_p) (tree, tree);
47  int (*start_inlining) (tree);
48  void (*end_inlining) (tree);
49  tree (*convert_parm_for_inlining) (tree, tree, tree, int);
50};
51
52struct lang_hooks_for_callgraph
53{
54  /* The node passed is a language-specific tree node.  If its contents
55     are relevant to use of other declarations, mark them.  */
56  tree (*analyze_expr) (tree *, int *, tree);
57
58  /* Produce RTL for function passed as argument.  */
59  void (*expand_function) (tree);
60};
61
62/* Lang hooks for management of language-specific data or status
63   when entering / leaving functions etc.  */
64struct lang_hooks_for_functions
65{
66  /* Called when entering a function.  */
67  void (*init) (struct function *);
68
69  /* Called when leaving a function.  */
70  void (*final) (struct function *);
71
72  /* Called when entering a nested function.  */
73  void (*enter_nested) (struct function *);
74
75  /* Called when leaving a nested function.  */
76  void (*leave_nested) (struct function *);
77
78  /* Determines if it's ok for a function to have no noreturn attribute.  */
79  bool (*missing_noreturn_ok_p) (tree);
80};
81
82/* The following hooks are used by tree-dump.c.  */
83
84struct lang_hooks_for_tree_dump
85{
86  /* Dump language-specific parts of tree nodes.  Returns nonzero if it
87     does not want the usual dumping of the second argument.  */
88  bool (*dump_tree) (void *, tree);
89
90  /* Determine type qualifiers in a language-specific way.  */
91  int (*type_quals) (tree);
92};
93
94/* Hooks related to types.  */
95
96struct lang_hooks_for_types
97{
98  /* Return a new type (with the indicated CODE), doing whatever
99     language-specific processing is required.  */
100  tree (*make_type) (enum tree_code);
101
102  /* Given MODE and UNSIGNEDP, return a suitable type-tree with that
103     mode.  */
104  tree (*type_for_mode) (enum machine_mode, int);
105
106  /* Given PRECISION and UNSIGNEDP, return a suitable type-tree for an
107     integer type with at least that precision.  */
108  tree (*type_for_size) (unsigned, int);
109
110  /* Given an integer type T, return a type like T but unsigned.
111     If T is unsigned, the value is T.  */
112  tree (*unsigned_type) (tree);
113
114  /* Given an integer type T, return a type like T but signed.
115     If T is signed, the value is T.  */
116  tree (*signed_type) (tree);
117
118  /* Return a type the same as TYPE except unsigned or signed
119     according to UNSIGNEDP.  */
120  tree (*signed_or_unsigned_type) (int, tree);
121
122  /* Given a type, apply default promotions to unnamed function
123     arguments and return the new type.  Return the same type if no
124     change.  Required by any language that supports variadic
125     arguments.  The default hook dies.  */
126  tree (*type_promotes_to) (tree);
127
128  /* Register TYPE as a builtin type with the indicated NAME.  The
129     TYPE is placed in the outermost lexical scope.  The semantics
130     should be analogous to:
131
132       typedef TYPE NAME;
133
134     in C.  The default hook ignores the declaration.  */
135  void (*register_builtin_type) (tree, const char *);
136
137  /* This routine is called in tree.c to print an error message for
138     invalid use of an incomplete type.  VALUE is the expression that
139     was used (or 0 if that isn't known) and TYPE is the type that was
140     invalid.  */
141  void (*incomplete_type_error) (tree value, tree type);
142
143  /* Called from assign_temp to return the maximum size, if there is one,
144     for a type.  */
145  tree (*max_size) (tree);
146
147  /* Register language specific type size variables as potentially OpenMP
148     firstprivate variables.  */
149  void (*omp_firstprivatize_type_sizes) (struct gimplify_omp_ctx *, tree);
150
151  /* Nonzero if types that are identical are to be hashed so that only
152     one copy is kept.  If a language requires unique types for each
153     user-specified type, such as Ada, this should be set to TRUE.  */
154  bool hash_types;
155};
156
157/* Language hooks related to decls and the symbol table.  */
158
159struct lang_hooks_for_decls
160{
161  /* Returns nonzero if we are in the global binding level.  Ada
162     returns -1 for an undocumented reason used in stor-layout.c.  */
163  int (*global_bindings_p) (void);
164
165  /* Insert BLOCK at the end of the list of subblocks of the
166     current binding level.  This is used when a BIND_EXPR is expanded,
167     to handle the BLOCK node inside the BIND_EXPR.  */
168  void (*insert_block) (tree);
169
170  /* Function to add a decl to the current scope level.  Takes one
171     argument, a decl to add.  Returns that decl, or, if the same
172     symbol is already declared, may return a different decl for that
173     name.  */
174  tree (*pushdecl) (tree);
175
176  /* Returns the chain of decls so far in the current scope level.  */
177  tree (*getdecls) (void);
178
179  /* Returns true when we should warn for an unused global DECL.
180     We will already have checked that it has static binding.  */
181  bool (*warn_unused_global) (tree);
182
183  /* Obtain a list of globals and do final output on them at end
184     of compilation */
185  void (*final_write_globals) (void);
186
187  /* Do necessary preparations before assemble_variable can proceed.  */
188  void (*prepare_assemble_variable) (tree);
189
190  /* True if this decl may be called via a sibcall.  */
191  bool (*ok_for_sibcall) (tree);
192
193  /* Return the COMDAT group into which this DECL should be placed.
194     It is known that the DECL belongs in *some* COMDAT group when
195     this hook is called.  The return value will be used immediately,
196     but not explicitly deallocated, so implementations should not use
197     xmalloc to allocate the string returned.  (Typically, the return
198     value will be the string already stored in an
199     IDENTIFIER_NODE.)  */
200  const char * (*comdat_group) (tree);
201
202  /* True if OpenMP should privatize what this DECL points to rather
203     than the DECL itself.  */
204  bool (*omp_privatize_by_reference) (tree);
205
206  /* Return sharing kind if OpenMP sharing attribute of DECL is
207     predetermined, OMP_CLAUSE_DEFAULT_UNSPECIFIED otherwise.  */
208  enum omp_clause_default_kind (*omp_predetermined_sharing) (tree);
209
210  /* Return true if DECL's DECL_VALUE_EXPR (if any) should be
211     disregarded in OpenMP construct, because it is going to be
212     remapped during OpenMP lowering.  SHARED is true if DECL
213     is going to be shared, false if it is going to be privatized.  */
214  bool (*omp_disregard_value_expr) (tree, bool);
215
216  /* Return true if DECL that is shared iff SHARED is true should
217     be put into OMP_CLAUSE_PRIVATE_DEBUG.  */
218  bool (*omp_private_debug_clause) (tree, bool);
219
220  /* Build and return code for a default constructor for DECL in
221     response to CLAUSE.  Return NULL if nothing to be done.  */
222  tree (*omp_clause_default_ctor) (tree clause, tree decl);
223
224  /* Build and return code for a copy constructor from SRC to DST.  */
225  tree (*omp_clause_copy_ctor) (tree clause, tree dst, tree src);
226
227  /* Similarly, except use an assignment operator instead.  */
228  tree (*omp_clause_assign_op) (tree clause, tree dst, tree src);
229
230  /* Build and return code destructing DECL.  Return NULL if nothing
231     to be done.  */
232  tree (*omp_clause_dtor) (tree clause, tree decl);
233};
234
235/* Language-specific hooks.  See langhooks-def.h for defaults.  */
236
237struct lang_hooks
238{
239  /* String identifying the front end.  e.g. "GNU C++".  */
240  const char *name;
241
242  /* sizeof (struct lang_identifier), so make_node () creates
243     identifier nodes long enough for the language-specific slots.  */
244  size_t identifier_size;
245
246  /* Determines the size of any language-specific tcc_constant or
247     tcc_exceptional nodes.  Since it is called from make_node, the
248     only information available is the tree code.  Expected to die
249     on unrecognized codes.  */
250  size_t (*tree_size) (enum tree_code);
251
252  /* The first callback made to the front end, for simple
253     initialization needed before any calls to handle_option.  Return
254     the language mask to filter the switch array with.  */
255  unsigned int (*init_options) (unsigned int argc, const char **argv);
256
257  /* Callback used to perform language-specific initialization for the
258     global diagnostic context structure.  */
259  void (*initialize_diagnostics) (struct diagnostic_context *);
260
261  /* Handle the switch CODE, which has real type enum opt_code from
262     options.h.  If the switch takes an argument, it is passed in ARG
263     which points to permanent storage.  The handler is responsible for
264     checking whether ARG is NULL, which indicates that no argument
265     was in fact supplied.  For -f and -W switches, VALUE is 1 or 0
266     for the positive and negative forms respectively.
267
268     Return 1 if the switch is valid, 0 if invalid, and -1 if it's
269     valid and should not be treated as language-independent too.  */
270  int (*handle_option) (size_t code, const char *arg, int value);
271
272  /* Return false to use the default complaint about a missing
273     argument, otherwise output a complaint and return true.  */
274  bool (*missing_argument) (const char *opt, size_t code);
275
276  /* Called when all command line options have been parsed to allow
277     further processing and initialization
278
279     Should return true to indicate that a compiler back-end is
280     not required, such as with the -E option.
281
282     If errorcount is nonzero after this call the compiler exits
283     immediately and the finish hook is not called.  */
284  bool (*post_options) (const char **);
285
286  /* Called after post_options to initialize the front end.  Return
287     false to indicate that no further compilation be performed, in
288     which case the finish hook is called immediately.  */
289  bool (*init) (void);
290
291  /* Called at the end of compilation, as a finalizer.  */
292  void (*finish) (void);
293
294  /* Parses the entire file.  The argument is nonzero to cause bison
295     parsers to dump debugging information during parsing.  */
296  void (*parse_file) (int);
297
298  /* Called immediately after parsing to clear the binding stack.  */
299  void (*clear_binding_stack) (void);
300
301  /* Called to obtain the alias set to be used for an expression or type.
302     Returns -1 if the language does nothing special for it.  */
303  HOST_WIDE_INT (*get_alias_set) (tree);
304
305  /* Called with an expression that is to be processed as a constant.
306     Returns either the same expression or a language-independent
307     constant equivalent to its input.  */
308  tree (*expand_constant) (tree);
309
310  /* Called by expand_expr for language-specific tree codes.
311     Fourth argument is actually an enum expand_modifier.  */
312  rtx (*expand_expr) (tree, rtx, enum machine_mode, int, rtx *);
313
314  /* Called by expand_expr to generate the definition of a decl.  Returns
315     1 if handled, 0 otherwise.  */
316  int (*expand_decl) (tree);
317
318  /* Hook called by safe_from_p for language-specific tree codes.  It is
319     up to the language front-end to install a hook if it has any such
320     codes that safe_from_p needs to know about.  Since same_from_p will
321     recursively explore the TREE_OPERANDs of an expression, this hook
322     should not reexamine those pieces.  This routine may recursively
323     call safe_from_p; it should always pass `0' as the TOP_P
324     parameter.  */
325  int (*safe_from_p) (rtx, tree);
326
327  /* Function to finish handling an incomplete decl at the end of
328     compilation.  Default hook is does nothing.  */
329  void (*finish_incomplete_decl) (tree);
330
331  /* Mark EXP saying that we need to be able to take the address of
332     it; it should not be allocated in a register.  Return true if
333     successful.  */
334  bool (*mark_addressable) (tree);
335
336  /* Hook called by staticp for language-specific tree codes.  */
337  tree (*staticp) (tree);
338
339  /* Replace the DECL_LANG_SPECIFIC data, which may be NULL, of the
340     DECL_NODE with a newly GC-allocated copy.  */
341  void (*dup_lang_specific_decl) (tree);
342
343  /* Set the DECL_ASSEMBLER_NAME for a node.  If it is the sort of
344     thing that the assembler should talk about, set
345     DECL_ASSEMBLER_NAME to an appropriate IDENTIFIER_NODE.
346     Otherwise, set it to the ERROR_MARK_NODE to ensure that the
347     assembler does not talk about it.  */
348  void (*set_decl_assembler_name) (tree);
349
350  /* Return nonzero if fold-const is free to use bit-field
351     optimizations, for instance in fold_truthop().  */
352  bool (*can_use_bit_fields_p) (void);
353
354  /* Nonzero if operations on types narrower than their mode should
355     have their results reduced to the precision of the type.  */
356  bool reduce_bit_field_operations;
357
358  /* Nonzero if this front end does not generate a dummy BLOCK between
359     the outermost scope of the function and the FUNCTION_DECL.  See
360     is_body_block in stmt.c, and its callers.  */
361  bool no_body_blocks;
362
363  /* The front end can add its own statistics to -fmem-report with
364     this hook.  It should output to stderr.  */
365  void (*print_statistics) (void);
366
367  /* Called by print_tree when there is a tree of class tcc_exceptional
368     that it doesn't know how to display.  */
369  lang_print_tree_hook print_xnode;
370
371  /* Called to print language-dependent parts of tcc_decl, tcc_type,
372     and IDENTIFIER_NODE nodes.  */
373  lang_print_tree_hook print_decl;
374  lang_print_tree_hook print_type;
375  lang_print_tree_hook print_identifier;
376
377  /* Computes the name to use to print a declaration.  DECL is the
378     non-NULL declaration in question.  VERBOSITY determines what
379     information will be printed: 0: DECL_NAME, demangled as
380     necessary.  1: and scope information.  2: and any other
381     information that might be interesting, such as function parameter
382     types in C++.  */
383  const char *(*decl_printable_name) (tree decl, int verbosity);
384
385  /* Computes the dwarf-2/3 name for a tree.  VERBOSITY determines what
386     information will be printed: 0: DECL_NAME, demangled as
387     necessary.  1: and scope information.  */
388  const char *(*dwarf_name) (tree, int verbosity);
389
390  /* This compares two types for equivalence ("compatible" in C-based languages).
391     This routine should only return 1 if it is sure.  It should not be used
392     in contexts where erroneously returning 0 causes problems.  */
393  int (*types_compatible_p) (tree x, tree y);
394
395  /* Given a CALL_EXPR, return a function decl that is its target.  */
396  tree (*lang_get_callee_fndecl) (tree);
397
398  /* Called by report_error_function to print out function name.  */
399  void (*print_error_function) (struct diagnostic_context *, const char *);
400
401  /* Called from expr_size to calculate the size of the value of an
402     expression in a language-dependent way.  Returns a tree for the size
403     in bytes.  A frontend can call lhd_expr_size to get the default
404     semantics in cases that it doesn't want to handle specially.  */
405  tree (*expr_size) (tree);
406
407  /* Convert a character from the host's to the target's character
408     set.  The character should be in what C calls the "basic source
409     character set" (roughly, the set of characters defined by plain
410     old ASCII).  The default is to return the character unchanged,
411     which is correct in most circumstances.  Note that both argument
412     and result should be sign-extended under -fsigned-char,
413     zero-extended under -fno-signed-char.  */
414  HOST_WIDE_INT (*to_target_charset) (HOST_WIDE_INT);
415
416  /* Pointers to machine-independent attribute tables, for front ends
417     using attribs.c.  If one is NULL, it is ignored.  Respectively, a
418     table of attributes specific to the language, a table of
419     attributes common to two or more languages (to allow easy
420     sharing), and a table of attributes for checking formats.  */
421  const struct attribute_spec *attribute_table;
422  const struct attribute_spec *common_attribute_table;
423  const struct attribute_spec *format_attribute_table;
424
425  /* Function-related language hooks.  */
426  struct lang_hooks_for_functions function;
427
428  struct lang_hooks_for_tree_inlining tree_inlining;
429
430  struct lang_hooks_for_callgraph callgraph;
431
432  struct lang_hooks_for_tree_dump tree_dump;
433
434  struct lang_hooks_for_decls decls;
435
436  struct lang_hooks_for_types types;
437
438  /* Perform language-specific gimplification on the argument.  Returns an
439     enum gimplify_status, though we can't see that type here.  */
440  int (*gimplify_expr) (tree *, tree *, tree *);
441
442  /* Fold an OBJ_TYPE_REF expression to the address of a function.
443     KNOWN_TYPE carries the true type of the OBJ_TYPE_REF_OBJECT.  */
444  tree (*fold_obj_type_ref) (tree, tree);
445
446  /* Return a definition for a builtin function named NAME and whose data type
447     is TYPE.  TYPE should be a function type with argument types.
448     FUNCTION_CODE tells later passes how to compile calls to this function.
449     See tree.h for its possible values.
450
451     If LIBRARY_NAME is nonzero, use that for DECL_ASSEMBLER_NAME,
452     the name to be called if we can't opencode the function.  If
453     ATTRS is nonzero, use that for the function's attribute list.  */
454  tree (*builtin_function) (const char *name, tree type, int function_code,
455			    enum built_in_class bt_class,
456			    const char *library_name, tree attrs);
457
458  /* Used to set up the tree_contains_structure array for a frontend. */
459  void (*init_ts) (void);
460
461  /* Called by recompute_tree_invariant_for_addr_expr to go from EXPR
462     to a contained expression or DECL, possibly updating *TC, *TI or
463     *SE if in the process TREE_CONSTANT, TREE_INVARIANT or
464     TREE_SIDE_EFFECTS need updating.  */
465  tree (*expr_to_decl) (tree expr, bool *tc, bool *ti, bool *se);
466
467  /* Whenever you add entries here, make sure you adjust langhooks-def.h
468     and langhooks.c accordingly.  */
469};
470
471/* Each front end provides its own.  */
472extern const struct lang_hooks lang_hooks;
473
474#endif /* GCC_LANG_HOOKS_H */
475