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 an internal label. */
78 void (* internal_label
) (FILE *, const char *, unsigned long);
80 /* Emit an assembler directive to set visibility for the symbol
81 associated with the tree decl. */
82 void (* visibility
) (tree
, int);
84 /* Output the assembler code for entry to a function. */
85 void (* function_prologue
) (FILE *, HOST_WIDE_INT
);
87 /* Output the assembler code for end of prologue. */
88 void (* function_end_prologue
) (FILE *);
90 /* Output the assembler code for start of epilogue. */
91 void (* function_begin_epilogue
) (FILE *);
93 /* Output the assembler code for function exit. */
94 void (* function_epilogue
) (FILE *, HOST_WIDE_INT
);
96 /* Switch to an arbitrary section NAME with attributes as
97 specified by FLAGS. */
98 void (* named_section
) (const char *, unsigned int);
100 /* Switch to the section that holds the exception table. */
101 void (* exception_section
) (void);
103 /* Switch to the section that holds the exception frames. */
104 void (* eh_frame_section
) (void);
106 /* Select and switch to a section for EXP. It may be a DECL or a
107 constant. RELOC is nonzero if runtime relocations must be applied;
108 bit 1 will be set if the runtime relocations require non-local
109 name resolution. ALIGN is the required alignment of the data. */
110 void (* select_section
) (tree
, int, unsigned HOST_WIDE_INT
);
112 /* Select and switch to a section for X with MODE. ALIGN is
113 the desired alignment of the data. */
114 void (* select_rtx_section
) (enum machine_mode
, rtx
,
115 unsigned HOST_WIDE_INT
);
117 /* Select a unique section name for DECL. RELOC is the same as
118 for SELECT_SECTION. */
119 void (* unique_section
) (tree
, int);
121 /* Output a constructor for a symbol with a given priority. */
122 void (* constructor
) (rtx
, int);
124 /* Output a destructor for a symbol with a given priority. */
125 void (* destructor
) (rtx
, int);
127 /* Output the assembler code for a thunk function. THUNK_DECL is the
128 declaration for the thunk function itself, FUNCTION is the decl for
129 the target function. DELTA is an immediate constant offset to be
130 added to THIS. If VCALL_OFFSET is nonzero, the word at
131 *(*this + vcall_offset) should be added to THIS. */
132 void (* output_mi_thunk
) (FILE *file
, tree thunk_decl
,
133 HOST_WIDE_INT delta
, HOST_WIDE_INT vcall_offset
,
136 /* Determine whether output_mi_thunk would succeed. */
137 /* ??? Ideally, this hook would not exist, and success or failure
138 would be returned from output_mi_thunk directly. But there's
139 too much undo-able setup involved in invoking output_mi_thunk.
140 Could be fixed by making output_mi_thunk emit rtl instead of
141 text to the output file. */
142 bool (* can_output_mi_thunk
) (tree thunk_decl
, HOST_WIDE_INT delta
,
143 HOST_WIDE_INT vcall_offset
,
146 /* Output any boilerplate text needed at the beginning of a
148 void (*file_start
) (void);
150 /* Output any boilerplate text needed at the end of a
152 void (*file_end
) (void);
154 /* Output an assembler pseudo-op to declare a library function name
156 void (*external_libcall
) (rtx
);
159 /* Functions relating to instruction scheduling. */
162 /* Given the current cost, COST, of an insn, INSN, calculate and
163 return a new cost based on its relationship to DEP_INSN through
164 the dependence LINK. The default is to make no adjustment. */
165 int (* adjust_cost
) (rtx insn
, rtx link
, rtx def_insn
, int cost
);
167 /* Adjust the priority of an insn as you see fit. Returns the new
169 int (* adjust_priority
) (rtx
, int);
171 /* Function which returns the maximum number of insns that can be
172 scheduled in the same machine cycle. This must be constant
173 over an entire compilation. The default is 1. */
174 int (* issue_rate
) (void);
176 /* Calculate how much this insn affects how many more insns we
177 can emit this cycle. Default is they all cost the same. */
178 int (* variable_issue
) (FILE *, int, rtx
, int);
180 /* Initialize machine-dependent scheduling code. */
181 void (* md_init
) (FILE *, int, int);
183 /* Finalize machine-dependent scheduling code. */
184 void (* md_finish
) (FILE *, int);
186 /* Reorder insns in a machine-dependent fashion, in two different
187 places. Default does nothing. */
188 int (* reorder
) (FILE *, int, rtx
*, int *, int);
189 int (* reorder2
) (FILE *, int, rtx
*, int *, int);
191 /* The following member value is a pointer to a function called
192 after evaluation forward dependencies of insns in chain given
193 by two parameter values (head and tail correspondingly). */
194 void (* dependencies_evaluation_hook
) (rtx
, rtx
);
196 /* The following member value is a pointer to a function returning
197 nonzero if we should use DFA based scheduling. The default is
198 to use the old pipeline scheduler. */
199 int (* use_dfa_pipeline_interface
) (void);
200 /* The values of all the following members are used only for the
201 DFA based scheduler: */
202 /* The values of the following four members are pointers to
203 functions used to simplify the automaton descriptions.
204 dfa_pre_cycle_insn and dfa_post_cycle_insn give functions
205 returning insns which are used to change the pipeline hazard
206 recognizer state when the new simulated processor cycle
207 correspondingly starts and finishes. The function defined by
208 init_dfa_pre_cycle_insn and init_dfa_post_cycle_insn are used
209 to initialize the corresponding insns. The default values of
210 the members result in not changing the automaton state when
211 the new simulated processor cycle correspondingly starts and
213 void (* init_dfa_pre_cycle_insn
) (void);
214 rtx (* dfa_pre_cycle_insn
) (void);
215 void (* init_dfa_post_cycle_insn
) (void);
216 rtx (* dfa_post_cycle_insn
) (void);
217 /* The following member value is a pointer to a function returning value
218 which defines how many insns in queue `ready' will we try for
219 multi-pass scheduling. if the member value is nonzero and the
220 function returns positive value, the DFA based scheduler will make
221 multi-pass scheduling for the first cycle. In other words, we will
222 try to choose ready insn which permits to start maximum number of
223 insns on the same cycle. */
224 int (* first_cycle_multipass_dfa_lookahead
) (void);
225 /* The following member value is pointer to a function controlling
226 what insns from the ready insn queue will be considered for the
227 multipass insn scheduling. If the hook returns zero for insn
228 passed as the parameter, the insn will be not chosen to be
230 int (* first_cycle_multipass_dfa_lookahead_guard
) (rtx
);
231 /* The following member value is pointer to a function called by
232 the insn scheduler before issuing insn passed as the third
233 parameter on given cycle. If the hook returns nonzero, the
234 insn is not issued on given processors cycle. Instead of that,
235 the processor cycle is advanced. If the value passed through
236 the last parameter is zero, the insn ready queue is not sorted
237 on the new cycle start as usually. The first parameter passes
238 file for debugging output. The second one passes the scheduler
239 verbose level of the debugging output. The forth and the fifth
240 parameter values are correspondingly processor cycle on which
241 the previous insn has been issued and the current processor
243 int (* dfa_new_cycle
) (FILE *, int, rtx
, int, int, int *);
244 /* The values of the following members are pointers to functions
245 used to improve the first cycle multipass scheduling by
246 inserting nop insns. dfa_scheduler_bubble gives a function
247 returning a nop insn with given index. The indexes start with
248 zero. The function should return NULL if there are no more nop
249 insns with indexes greater than given index. To initialize the
250 nop insn the function given by member
251 init_dfa_scheduler_bubbles is used. The default values of the
252 members result in not inserting nop insns during the multipass
254 void (* init_dfa_bubbles
) (void);
255 rtx (* dfa_bubble
) (int);
256 /* The following member value is a pointer to a function called
257 by the insn scheduler. It should return true if there exists a
258 dependence which is considered costly by the target, between
259 the insn passed as the first parameter, and the insn passed as
260 the second parameter. The third parameter is the INSN_DEPEND
261 link that represents the dependence between the two insns. The
262 fourth argument is the cost of the dependence as estimated by
263 the scheduler. The last argument is the distance in cycles
264 between the already scheduled insn (first parameter) and the
265 the second insn (second parameter). */
266 bool (* is_costly_dependence
) (rtx
, rtx
, rtx
, int, int);
269 /* Given two decls, merge their attributes and return the result. */
270 tree (* merge_decl_attributes
) (tree
, tree
);
272 /* Given two types, merge their attributes and return the result. */
273 tree (* merge_type_attributes
) (tree
, tree
);
275 /* Table of machine attributes and functions to handle them.
277 const struct attribute_spec
*attribute_table
;
279 /* Return zero if the attributes on TYPE1 and TYPE2 are incompatible,
280 one if they are compatible and two if they are nearly compatible
281 (which causes a warning to be generated). */
282 int (* comp_type_attributes
) (tree type1
, tree type2
);
284 /* Assign default attributes to the newly defined TYPE. */
285 void (* set_default_type_attributes
) (tree type
);
287 /* Insert attributes on the newly created DECL. */
288 void (* insert_attributes
) (tree decl
, tree
*attributes
);
290 /* Return true if FNDECL (which has at least one machine attribute)
291 can be inlined despite its machine attributes, false otherwise. */
292 bool (* function_attribute_inlinable_p
) (tree fndecl
);
294 /* Return true if bitfields in RECORD_TYPE should follow the
295 Microsoft Visual C++ bitfield layout rules. */
296 bool (* ms_bitfield_layout_p
) (tree record_type
);
298 /* Set up target-specific built-in functions. */
299 void (* init_builtins
) (void);
301 /* Expand a target-specific builtin. */
302 rtx (* expand_builtin
) (tree exp
, rtx target
, rtx subtarget
,
303 enum machine_mode mode
, int ignore
);
305 /* Make any adjustments to libfunc names needed for this target. */
306 void (* init_libfuncs
) (void);
308 /* Given a decl, a section name, and whether the decl initializer
309 has relocs, choose attributes for the section. */
310 /* ??? Should be merged with SELECT_SECTION and UNIQUE_SECTION. */
311 unsigned int (* section_type_flags
) (tree
, const char *, int);
313 /* True if new jumps cannot be created, to replace existing ones or
314 not, at the current point in the compilation. */
315 bool (* cannot_modify_jumps_p
) (void);
317 /* Return a register class for which branch target register
318 optimizations should be applied. */
319 int (* branch_target_register_class
) (void);
321 /* Return true if branch target register optimizations should include
322 callee-saved registers that are not already live during the current
323 function. AFTER_PE_GEN is true if prologues and epilogues have
324 already been generated. */
325 bool (* branch_target_register_callee_saved
) (bool after_pe_gen
);
327 /* True if the constant X cannot be placed in the constant pool. */
328 bool (* cannot_force_const_mem
) (rtx
);
330 /* True if the insn X cannot be duplicated. */
331 bool (* cannot_copy_insn_p
) (rtx
);
333 /* Given an address RTX, undo the effects of LEGITIMIZE_ADDRESS. */
334 rtx (* delegitimize_address
) (rtx
);
336 /* True if it is OK to do sibling call optimization for the specified
337 call expression EXP. DECL will be the called function, or NULL if
338 this is an indirect call. */
339 bool (*function_ok_for_sibcall
) (tree decl
, tree exp
);
341 /* True if EXP should be placed in a "small data" section. */
342 bool (* in_small_data_p
) (tree
);
344 /* True if EXP names an object for which name resolution must resolve
345 to the current module. */
346 bool (* binds_local_p
) (tree
);
348 /* Do something target-specific to record properties of the DECL into
349 the associated SYMBOL_REF. */
350 void (* encode_section_info
) (tree
, rtx
, int);
352 /* Undo the effects of encode_section_info on the symbol string. */
353 const char * (* strip_name_encoding
) (const char *);
355 /* True if MODE is valid for a pointer in __attribute__((mode("MODE"))). */
356 bool (* valid_pointer_mode
) (enum machine_mode mode
);
358 /* True if a vector is opaque. */
359 bool (* vector_opaque_p
) (tree
);
361 /* Compute a (partial) cost for rtx X. Return true if the complete
362 cost has been computed, and false if subexpressions should be
363 scanned. In either case, *TOTAL contains the cost result. */
364 /* Note that CODE and OUTER_CODE ought to be RTX_CODE, but that's
365 not necessarily defined at this point. */
366 bool (* rtx_costs
) (rtx x
, int code
, int outer_code
, int *total
);
368 /* Compute the cost of X, used as an address. Never called with
369 invalid addresses. */
370 int (* address_cost
) (rtx x
);
372 /* Given a register, this hook should return a parallel of registers
373 to represent where to find the register pieces. Define this hook
374 if the register and its mode are represented in Dwarf in
375 non-contiguous locations, or if the register should be
376 represented in more than one register in Dwarf. Otherwise, this
377 hook should return NULL_RTX. */
378 rtx (* dwarf_register_span
) (rtx
);
380 /* Fetch the fixed register(s) which hold condition codes, for
381 targets where it makes sense to look for duplicate assignments to
382 the condition codes. This should return true if there is such a
383 register, false otherwise. The arguments should be set to the
384 fixed register numbers. Up to two condition code registers are
385 supported. If there is only one for this target, the int pointed
386 at by the second argument should be set to -1. */
387 bool (* fixed_condition_code_regs
) (unsigned int *, unsigned int *);
389 /* If two condition code modes are compatible, return a condition
390 code mode which is compatible with both, such that a comparison
391 done in the returned mode will work for both of the original
392 modes. If the condition code modes are not compatible, return
394 enum machine_mode (* cc_modes_compatible
) (enum machine_mode
,
397 /* Do machine-dependent code transformations. Called just before
398 delayed-branch scheduling. */
399 void (* machine_dependent_reorg
) (void);
401 /* Create the __builtin_va_list type. */
402 tree (* build_builtin_va_list
) (void);
404 /* Validity-checking routines for PCH files, target-specific.
405 get_pch_validity returns a pointer to the data to be stored,
406 and stores the size in its argument. pch_valid_p gets the same
407 information back and returns NULL if the PCH is valid,
408 or an error message if not.
410 void * (* get_pch_validity
) (size_t *);
411 const char * (* pch_valid_p
) (const void *, size_t);
413 /* Leave the boolean fields at the end. */
415 /* True if arbitrary sections are supported. */
416 bool have_named_sections
;
418 /* True if "native" constructors and destructors are supported,
419 false if we're using collect2 for the job. */
420 bool have_ctors_dtors
;
422 /* True if thread-local storage is supported. */
425 /* True if a small readonly data section is supported. */
426 bool have_srodata_section
;
428 /* True if EH frame info sections should be zero-terminated. */
429 bool terminate_dw2_eh_frame_info
;
431 /* True if #NO_APP should be emitted at the beginning of
433 bool file_start_app_off
;
435 /* True if output_file_directive should be called for main_input_filename
436 at the beginning of assembly output. */
437 bool file_start_file_directive
;
439 /* Functions relating to calls - argument passing, returns, etc. */
441 bool (*promote_function_args
) (tree fntype
);
442 bool (*promote_function_return
) (tree fntype
);
443 bool (*promote_prototypes
) (tree fntype
);
444 rtx (*struct_value_rtx
) (tree fndecl
, int incoming
);
445 bool (*return_in_memory
) (tree type
, tree fndecl
);
446 bool (*return_in_msb
) (tree type
);
447 rtx (*expand_builtin_saveregs
) (void);
448 /* Returns pretend_argument_size. */
449 void (*setup_incoming_varargs
) (CUMULATIVE_ARGS
*ca
, enum machine_mode mode
,
450 tree type
, int *pretend_arg_size
, int second_time
);
451 bool (*strict_argument_naming
) (CUMULATIVE_ARGS
*ca
);
452 /* Returns true if we should use
453 targetm.calls.setup_incoming_varargs() and/or
454 targetm.calls.strict_argument_naming(). */
455 bool (*pretend_outgoing_varargs_named
) (CUMULATIVE_ARGS
*ca
);
459 extern struct gcc_target targetm
;