1 /* Data structure definitions for a generic GCC target.
2 Copyright (C) 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
4 This program is free software; you can redistribute it and/or modify it
5 under the terms of the GNU General Public License as published by the
6 Free Software Foundation; either version 2, or (at your option) any
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program; if not, write to the Free Software
16 Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
18 In other words, you are welcome to use, share and improve this program.
19 You are forbidden to forbid anyone else to use, share and improve
20 what you give them. Help stamp out software-hoarding! */
22 /* This file contains a data structure that describes a GCC target.
23 At present it is incomplete, but in future it should grow to
24 contain most or all target machine and target O/S specific
27 This structure has its initializer declared in target-def.h in the
28 form of large macro TARGET_INITIALIZER that expands to many smaller
31 The smaller macros each initialize one component of the structure,
32 and each has a default. Each target should have a file that
33 includes target.h and target-def.h, and overrides any inappropriate
34 defaults by undefining the relevant macro and defining a suitable
35 replacement. That file should then contain the definition of
38 struct gcc_target targetm = TARGET_INITIALIZER;
40 Doing things this way allows us to bring together everything that
41 defines a GCC target. By supplying a default that is appropriate
42 to most targets, we can easily add new items without needing to
43 edit dozens of target configuration files. It should also allow us
44 to gradually reduce the amount of conditional compilation that is
45 scattered throughout GCC. */
51 /* Functions that output assembler for the target. */
54 /* Opening and closing parentheses for asm expression grouping. */
55 const char *open_paren
, *close_paren
;
57 /* Assembler instructions for creating various kinds of integer object. */
65 } aligned_op
, unaligned_op
;
67 /* Try to output the assembler code for an integer object whose
68 value is given by X. SIZE is the size of the object in bytes and
69 ALIGNED_P indicates whether it is aligned. Return true if
70 successful. Only handles cases for which BYTE_OP, ALIGNED_OP
71 and UNALIGNED_OP are NULL. */
72 bool (* integer
) (rtx x
, unsigned int size
, int aligned_p
);
74 /* Output code that will globalize a label. */
75 void (* globalize_label
) (FILE *, const char *);
77 /* Output code that will emit a label for unwind info, if this
78 target requires such labels. Second argument is the decl the
79 unwind info is associated with, third is is a boolean: true if
80 this is only a placeholder for an omitted FDE. */
81 void (* unwind_label
) (FILE *, tree
, int);
83 /* Output an internal label. */
84 void (* internal_label
) (FILE *, const char *, unsigned long);
86 /* Emit an assembler directive to set visibility for the symbol
87 associated with the tree decl. */
88 void (* visibility
) (tree
, int);
90 /* Output the assembler code for entry to a function. */
91 void (* function_prologue
) (FILE *, HOST_WIDE_INT
);
93 /* Output the assembler code for end of prologue. */
94 void (* function_end_prologue
) (FILE *);
96 /* Output the assembler code for start of epilogue. */
97 void (* function_begin_epilogue
) (FILE *);
99 /* Output the assembler code for function exit. */
100 void (* function_epilogue
) (FILE *, HOST_WIDE_INT
);
102 /* Switch to an arbitrary section NAME with attributes as
103 specified by FLAGS. */
104 void (* named_section
) (const char *, unsigned int);
106 /* Switch to the section that holds the exception table. */
107 void (* exception_section
) (void);
109 /* Switch to the section that holds the exception frames. */
110 void (* eh_frame_section
) (void);
112 /* Select and switch to a section for EXP. It may be a DECL or a
113 constant. RELOC is nonzero if runtime relocations must be applied;
114 bit 1 will be set if the runtime relocations require non-local
115 name resolution. ALIGN is the required alignment of the data. */
116 void (* select_section
) (tree
, int, unsigned HOST_WIDE_INT
);
118 /* Select and switch to a section for X with MODE. ALIGN is
119 the desired alignment of the data. */
120 void (* select_rtx_section
) (enum machine_mode
, rtx
,
121 unsigned HOST_WIDE_INT
);
123 /* Select a unique section name for DECL. RELOC is the same as
124 for SELECT_SECTION. */
125 void (* unique_section
) (tree
, int);
127 /* Output a constructor for a symbol with a given priority. */
128 void (* constructor
) (rtx
, int);
130 /* Output a destructor for a symbol with a given priority. */
131 void (* destructor
) (rtx
, int);
133 /* Output the assembler code for a thunk function. THUNK_DECL is the
134 declaration for the thunk function itself, FUNCTION is the decl for
135 the target function. DELTA is an immediate constant offset to be
136 added to THIS. If VCALL_OFFSET is nonzero, the word at
137 *(*this + vcall_offset) should be added to THIS. */
138 void (* output_mi_thunk
) (FILE *file
, tree thunk_decl
,
139 HOST_WIDE_INT delta
, HOST_WIDE_INT vcall_offset
,
142 /* Determine whether output_mi_thunk would succeed. */
143 /* ??? Ideally, this hook would not exist, and success or failure
144 would be returned from output_mi_thunk directly. But there's
145 too much undo-able setup involved in invoking output_mi_thunk.
146 Could be fixed by making output_mi_thunk emit rtl instead of
147 text to the output file. */
148 bool (* can_output_mi_thunk
) (tree thunk_decl
, HOST_WIDE_INT delta
,
149 HOST_WIDE_INT vcall_offset
,
152 /* Output any boilerplate text needed at the beginning of a
154 void (*file_start
) (void);
156 /* Output any boilerplate text needed at the end of a
158 void (*file_end
) (void);
160 /* Output an assembler pseudo-op to declare a library function name
162 void (*external_libcall
) (rtx
);
165 /* Functions relating to instruction scheduling. */
168 /* Given the current cost, COST, of an insn, INSN, calculate and
169 return a new cost based on its relationship to DEP_INSN through
170 the dependence LINK. The default is to make no adjustment. */
171 int (* adjust_cost
) (rtx insn
, rtx link
, rtx def_insn
, int cost
);
173 /* Adjust the priority of an insn as you see fit. Returns the new
175 int (* adjust_priority
) (rtx
, int);
177 /* Function which returns the maximum number of insns that can be
178 scheduled in the same machine cycle. This must be constant
179 over an entire compilation. The default is 1. */
180 int (* issue_rate
) (void);
182 /* Calculate how much this insn affects how many more insns we
183 can emit this cycle. Default is they all cost the same. */
184 int (* variable_issue
) (FILE *, int, rtx
, int);
186 /* Initialize machine-dependent scheduling code. */
187 void (* md_init
) (FILE *, int, int);
189 /* Finalize machine-dependent scheduling code. */
190 void (* md_finish
) (FILE *, int);
192 /* Initialize machine-dependent function while scheduling code. */
193 void (* md_init_global
) (FILE *, int, int);
195 /* Finalize machine-dependent function wide scheduling code. */
196 void (* md_finish_global
) (FILE *, int);
198 /* Reorder insns in a machine-dependent fashion, in two different
199 places. Default does nothing. */
200 int (* reorder
) (FILE *, int, rtx
*, int *, int);
201 int (* reorder2
) (FILE *, int, rtx
*, int *, int);
203 /* The following member value is a pointer to a function called
204 after evaluation forward dependencies of insns in chain given
205 by two parameter values (head and tail correspondingly). */
206 void (* dependencies_evaluation_hook
) (rtx
, rtx
);
208 /* The following member value is a pointer to a function returning
209 nonzero if we should use DFA based scheduling. The default is
210 to use the old pipeline scheduler. */
211 int (* use_dfa_pipeline_interface
) (void);
212 /* The values of all the following members are used only for the
213 DFA based scheduler: */
214 /* The values of the following four members are pointers to
215 functions used to simplify the automaton descriptions.
216 dfa_pre_cycle_insn and dfa_post_cycle_insn give functions
217 returning insns which are used to change the pipeline hazard
218 recognizer state when the new simulated processor cycle
219 correspondingly starts and finishes. The function defined by
220 init_dfa_pre_cycle_insn and init_dfa_post_cycle_insn are used
221 to initialize the corresponding insns. The default values of
222 the members result in not changing the automaton state when
223 the new simulated processor cycle correspondingly starts and
225 void (* init_dfa_pre_cycle_insn
) (void);
226 rtx (* dfa_pre_cycle_insn
) (void);
227 void (* init_dfa_post_cycle_insn
) (void);
228 rtx (* dfa_post_cycle_insn
) (void);
229 /* The following member value is a pointer to a function returning value
230 which defines how many insns in queue `ready' will we try for
231 multi-pass scheduling. if the member value is nonzero and the
232 function returns positive value, the DFA based scheduler will make
233 multi-pass scheduling for the first cycle. In other words, we will
234 try to choose ready insn which permits to start maximum number of
235 insns on the same cycle. */
236 int (* first_cycle_multipass_dfa_lookahead
) (void);
237 /* The following member value is pointer to a function controlling
238 what insns from the ready insn queue will be considered for the
239 multipass insn scheduling. If the hook returns zero for insn
240 passed as the parameter, the insn will be not chosen to be
242 int (* first_cycle_multipass_dfa_lookahead_guard
) (rtx
);
243 /* The following member value is pointer to a function called by
244 the insn scheduler before issuing insn passed as the third
245 parameter on given cycle. If the hook returns nonzero, the
246 insn is not issued on given processors cycle. Instead of that,
247 the processor cycle is advanced. If the value passed through
248 the last parameter is zero, the insn ready queue is not sorted
249 on the new cycle start as usually. The first parameter passes
250 file for debugging output. The second one passes the scheduler
251 verbose level of the debugging output. The forth and the fifth
252 parameter values are correspondingly processor cycle on which
253 the previous insn has been issued and the current processor
255 int (* dfa_new_cycle
) (FILE *, int, rtx
, int, int, int *);
256 /* The values of the following members are pointers to functions
257 used to improve the first cycle multipass scheduling by
258 inserting nop insns. dfa_scheduler_bubble gives a function
259 returning a nop insn with given index. The indexes start with
260 zero. The function should return NULL if there are no more nop
261 insns with indexes greater than given index. To initialize the
262 nop insn the function given by member
263 init_dfa_scheduler_bubbles is used. The default values of the
264 members result in not inserting nop insns during the multipass
266 void (* init_dfa_bubbles
) (void);
267 rtx (* dfa_bubble
) (int);
268 /* The following member value is a pointer to a function called
269 by the insn scheduler. It should return true if there exists a
270 dependence which is considered costly by the target, between
271 the insn passed as the first parameter, and the insn passed as
272 the second parameter. The third parameter is the INSN_DEPEND
273 link that represents the dependence between the two insns. The
274 fourth argument is the cost of the dependence as estimated by
275 the scheduler. The last argument is the distance in cycles
276 between the already scheduled insn (first parameter) and the
277 the second insn (second parameter). */
278 bool (* is_costly_dependence
) (rtx
, rtx
, rtx
, int, int);
281 /* Given two decls, merge their attributes and return the result. */
282 tree (* merge_decl_attributes
) (tree
, tree
);
284 /* Given two types, merge their attributes and return the result. */
285 tree (* merge_type_attributes
) (tree
, tree
);
287 /* Table of machine attributes and functions to handle them.
289 const struct attribute_spec
*attribute_table
;
291 /* Return zero if the attributes on TYPE1 and TYPE2 are incompatible,
292 one if they are compatible and two if they are nearly compatible
293 (which causes a warning to be generated). */
294 int (* comp_type_attributes
) (tree type1
, tree type2
);
296 /* Assign default attributes to the newly defined TYPE. */
297 void (* set_default_type_attributes
) (tree type
);
299 /* Insert attributes on the newly created DECL. */
300 void (* insert_attributes
) (tree decl
, tree
*attributes
);
302 /* Return true if FNDECL (which has at least one machine attribute)
303 can be inlined despite its machine attributes, false otherwise. */
304 bool (* function_attribute_inlinable_p
) (tree fndecl
);
306 /* Return true if bitfields in RECORD_TYPE should follow the
307 Microsoft Visual C++ bitfield layout rules. */
308 bool (* ms_bitfield_layout_p
) (tree record_type
);
310 /* Return true if anonymous bitfields affect structure alignment. */
311 bool (* align_anon_bitfield
) (void);
313 /* Set up target-specific built-in functions. */
314 void (* init_builtins
) (void);
316 /* Expand a target-specific builtin. */
317 rtx (* expand_builtin
) (tree exp
, rtx target
, rtx subtarget
,
318 enum machine_mode mode
, int ignore
);
320 /* For a vendor-specific fundamental TYPE, return a pointer to
321 a statically-allocated string containing the C++ mangling for
322 TYPE. In all other cases, return NULL. */
323 const char * (* mangle_fundamental_type
) (tree type
);
325 /* Make any adjustments to libfunc names needed for this target. */
326 void (* init_libfuncs
) (void);
328 /* Given a decl, a section name, and whether the decl initializer
329 has relocs, choose attributes for the section. */
330 /* ??? Should be merged with SELECT_SECTION and UNIQUE_SECTION. */
331 unsigned int (* section_type_flags
) (tree
, const char *, int);
333 /* True if new jumps cannot be created, to replace existing ones or
334 not, at the current point in the compilation. */
335 bool (* cannot_modify_jumps_p
) (void);
337 /* Return a register class for which branch target register
338 optimizations should be applied. */
339 int (* branch_target_register_class
) (void);
341 /* Return true if branch target register optimizations should include
342 callee-saved registers that are not already live during the current
343 function. AFTER_PE_GEN is true if prologues and epilogues have
344 already been generated. */
345 bool (* branch_target_register_callee_saved
) (bool after_pe_gen
);
347 /* True if the constant X cannot be placed in the constant pool. */
348 bool (* cannot_force_const_mem
) (rtx
);
350 /* True if the insn X cannot be duplicated. */
351 bool (* cannot_copy_insn_p
) (rtx
);
353 /* Given an address RTX, undo the effects of LEGITIMIZE_ADDRESS. */
354 rtx (* delegitimize_address
) (rtx
);
356 /* True if it is OK to do sibling call optimization for the specified
357 call expression EXP. DECL will be the called function, or NULL if
358 this is an indirect call. */
359 bool (*function_ok_for_sibcall
) (tree decl
, tree exp
);
361 /* True if EXP should be placed in a "small data" section. */
362 bool (* in_small_data_p
) (tree
);
364 /* True if EXP names an object for which name resolution must resolve
365 to the current module. */
366 bool (* binds_local_p
) (tree
);
368 /* Do something target-specific to record properties of the DECL into
369 the associated SYMBOL_REF. */
370 void (* encode_section_info
) (tree
, rtx
, int);
372 /* Undo the effects of encode_section_info on the symbol string. */
373 const char * (* strip_name_encoding
) (const char *);
375 /* True if MODE is valid for a pointer in __attribute__((mode("MODE"))). */
376 bool (* valid_pointer_mode
) (enum machine_mode mode
);
378 /* True if a vector is opaque. */
379 bool (* vector_opaque_p
) (tree
);
381 /* Compute a (partial) cost for rtx X. Return true if the complete
382 cost has been computed, and false if subexpressions should be
383 scanned. In either case, *TOTAL contains the cost result. */
384 /* Note that CODE and OUTER_CODE ought to be RTX_CODE, but that's
385 not necessarily defined at this point. */
386 bool (* rtx_costs
) (rtx x
, int code
, int outer_code
, int *total
);
388 /* Compute the cost of X, used as an address. Never called with
389 invalid addresses. */
390 int (* address_cost
) (rtx x
);
392 /* Given a register, this hook should return a parallel of registers
393 to represent where to find the register pieces. Define this hook
394 if the register and its mode are represented in Dwarf in
395 non-contiguous locations, or if the register should be
396 represented in more than one register in Dwarf. Otherwise, this
397 hook should return NULL_RTX. */
398 rtx (* dwarf_register_span
) (rtx
);
400 /* Fetch the fixed register(s) which hold condition codes, for
401 targets where it makes sense to look for duplicate assignments to
402 the condition codes. This should return true if there is such a
403 register, false otherwise. The arguments should be set to the
404 fixed register numbers. Up to two condition code registers are
405 supported. If there is only one for this target, the int pointed
406 at by the second argument should be set to -1. */
407 bool (* fixed_condition_code_regs
) (unsigned int *, unsigned int *);
409 /* If two condition code modes are compatible, return a condition
410 code mode which is compatible with both, such that a comparison
411 done in the returned mode will work for both of the original
412 modes. If the condition code modes are not compatible, return
414 enum machine_mode (* cc_modes_compatible
) (enum machine_mode
,
417 /* Do machine-dependent code transformations. Called just before
418 delayed-branch scheduling. */
419 void (* machine_dependent_reorg
) (void);
421 /* Create the __builtin_va_list type. */
422 tree (* build_builtin_va_list
) (void);
424 /* Validity-checking routines for PCH files, target-specific.
425 get_pch_validity returns a pointer to the data to be stored,
426 and stores the size in its argument. pch_valid_p gets the same
427 information back and returns NULL if the PCH is valid,
428 or an error message if not.
430 void * (* get_pch_validity
) (size_t *);
431 const char * (* pch_valid_p
) (const void *, size_t);
433 /* True if the compiler should give an enum type only as many
434 bytes as it takes to represent the range of possible values of
436 bool (* default_short_enums
) (void);
438 /* This target hook returns an rtx that is used to store the address
439 of the current frame into the built-in setjmp buffer. */
440 rtx (* builtin_setjmp_frame_value
) (void);
442 /* This target hook should add STRING_CST trees for any hard regs
443 the port wishes to automatically clobber for all asms. */
444 tree (* md_asm_clobbers
) (tree
);
446 /* Functions relating to calls - argument passing, returns, etc. */
448 bool (*promote_function_args
) (tree fntype
);
449 bool (*promote_function_return
) (tree fntype
);
450 bool (*promote_prototypes
) (tree fntype
);
451 rtx (*struct_value_rtx
) (tree fndecl
, int incoming
);
452 bool (*return_in_memory
) (tree type
, tree fndecl
);
453 bool (*return_in_msb
) (tree type
);
454 rtx (*expand_builtin_saveregs
) (void);
455 /* Returns pretend_argument_size. */
456 void (*setup_incoming_varargs
) (CUMULATIVE_ARGS
*ca
, enum machine_mode mode
,
457 tree type
, int *pretend_arg_size
,
459 bool (*strict_argument_naming
) (CUMULATIVE_ARGS
*ca
);
460 /* Returns true if we should use
461 targetm.calls.setup_incoming_varargs() and/or
462 targetm.calls.strict_argument_naming(). */
463 bool (*pretend_outgoing_varargs_named
) (CUMULATIVE_ARGS
*ca
);
465 /* Given a complex type T, return true if a parameter of type T
466 should be passed as two scalars. */
467 bool (* split_complex_arg
) (tree type
);
470 /* Leave the boolean fields at the end. */
472 /* True if arbitrary sections are supported. */
473 bool have_named_sections
;
475 /* True if "native" constructors and destructors are supported,
476 false if we're using collect2 for the job. */
477 bool have_ctors_dtors
;
479 /* True if thread-local storage is supported. */
482 /* True if a small readonly data section is supported. */
483 bool have_srodata_section
;
485 /* True if EH frame info sections should be zero-terminated. */
486 bool terminate_dw2_eh_frame_info
;
488 /* True if #NO_APP should be emitted at the beginning of
490 bool file_start_app_off
;
492 /* True if output_file_directive should be called for main_input_filename
493 at the beginning of assembly output. */
494 bool file_start_file_directive
;
496 /* Leave the boolean fields at the end. */
499 extern struct gcc_target targetm
;