1 /* Structure for saving state for a nested function. 2 Copyright (C) 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 3 1999, 2000, 2003, 2004, 2005 Free Software Foundation, Inc. 4 5 This file is part of GCC. 6 7 GCC is free software; you can redistribute it and/or modify it under 8 the terms of the GNU General Public License as published by the Free 9 Software Foundation; either version 2, or (at your option) any later 10 version. 11 12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY 13 WARRANTY; without even the implied warranty of MERCHANTABILITY or 14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 15 for more details. 16 17 You should have received a copy of the GNU General Public License 18 along with GCC; see the file COPYING. If not, write to the Free 19 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 20 02110-1301, USA. */ 21 22 #ifndef GCC_FUNCTION_H 23 #define GCC_FUNCTION_H 24 25 #include "tree.h" 26 #include "hashtab.h" 27 28 struct var_refs_queue GTY(()) 29 { 30 rtx modified; 31 enum machine_mode promoted_mode; 32 int unsignedp; 33 struct var_refs_queue *next; 34 }; 35 36 /* Stack of pending (incomplete) sequences saved by `start_sequence'. 37 Each element describes one pending sequence. 38 The main insn-chain is saved in the last element of the chain, 39 unless the chain is empty. */ 40 41 struct sequence_stack GTY(()) 42 { 43 /* First and last insns in the chain of the saved sequence. */ 44 rtx first; 45 rtx last; 46 struct sequence_stack *next; 47 }; 48 49 extern struct sequence_stack *sequence_stack; 50 51 /* Stack of single obstacks. */ 52 53 struct simple_obstack_stack 54 { 55 struct obstack *obstack; 56 struct simple_obstack_stack *next; 57 }; 58 59 struct emit_status GTY(()) 60 { 61 /* This is reset to LAST_VIRTUAL_REGISTER + 1 at the start of each function. 62 After rtl generation, it is 1 plus the largest register number used. */ 63 int x_reg_rtx_no; 64 65 /* Lowest label number in current function. */ 66 int x_first_label_num; 67 68 /* The ends of the doubly-linked chain of rtl for the current function. 69 Both are reset to null at the start of rtl generation for the function. 70 71 start_sequence saves both of these on `sequence_stack' and then starts 72 a new, nested sequence of insns. */ 73 rtx x_first_insn; 74 rtx x_last_insn; 75 76 /* Stack of pending (incomplete) sequences saved by `start_sequence'. 77 Each element describes one pending sequence. 78 The main insn-chain is saved in the last element of the chain, 79 unless the chain is empty. */ 80 struct sequence_stack *sequence_stack; 81 82 /* INSN_UID for next insn emitted. 83 Reset to 1 for each function compiled. */ 84 int x_cur_insn_uid; 85 86 /* Location the last line-number NOTE emitted. 87 This is used to avoid generating duplicates. */ 88 location_t x_last_location; 89 90 /* The length of the regno_pointer_align, regno_decl, and x_regno_reg_rtx 91 vectors. Since these vectors are needed during the expansion phase when 92 the total number of registers in the function is not yet known, the 93 vectors are copied and made bigger when necessary. */ 94 int regno_pointer_align_length; 95 96 /* Indexed by pseudo register number, if nonzero gives the known alignment 97 for that pseudo (if REG_POINTER is set in x_regno_reg_rtx). 98 Allocated in parallel with x_regno_reg_rtx. */ 99 unsigned char * GTY ((length ("%h.x_reg_rtx_no"))) 100 regno_pointer_align; 101 102 /* Indexed by pseudo register number, gives the rtx for that pseudo. 103 Allocated in parallel with regno_pointer_align. */ 104 rtx * GTY ((length ("%h.x_reg_rtx_no"))) x_regno_reg_rtx; 105 }; 106 107 /* For backward compatibility... eventually these should all go away. */ 108 #define reg_rtx_no (cfun->emit->x_reg_rtx_no) 109 #define regno_reg_rtx (cfun->emit->x_regno_reg_rtx) 110 #define seq_stack (cfun->emit->sequence_stack) 111 112 #define REGNO_POINTER_ALIGN(REGNO) (cfun->emit->regno_pointer_align[REGNO]) 113 114 struct expr_status GTY(()) 115 { 116 /* Number of units that we should eventually pop off the stack. 117 These are the arguments to function calls that have already returned. */ 118 int x_pending_stack_adjust; 119 120 /* Under some ABIs, it is the caller's responsibility to pop arguments 121 pushed for function calls. A naive implementation would simply pop 122 the arguments immediately after each call. However, if several 123 function calls are made in a row, it is typically cheaper to pop 124 all the arguments after all of the calls are complete since a 125 single pop instruction can be used. Therefore, GCC attempts to 126 defer popping the arguments until absolutely necessary. (For 127 example, at the end of a conditional, the arguments must be popped, 128 since code outside the conditional won't know whether or not the 129 arguments need to be popped.) 130 131 When INHIBIT_DEFER_POP is nonzero, however, the compiler does not 132 attempt to defer pops. Instead, the stack is popped immediately 133 after each call. Rather then setting this variable directly, use 134 NO_DEFER_POP and OK_DEFER_POP. */ 135 int x_inhibit_defer_pop; 136 137 /* If PREFERRED_STACK_BOUNDARY and PUSH_ROUNDING are defined, the stack 138 boundary can be momentarily unaligned while pushing the arguments. 139 Record the delta since last aligned boundary here in order to get 140 stack alignment in the nested function calls working right. */ 141 int x_stack_pointer_delta; 142 143 /* Nonzero means __builtin_saveregs has already been done in this function. 144 The value is the pseudoreg containing the value __builtin_saveregs 145 returned. */ 146 rtx x_saveregs_value; 147 148 /* Similarly for __builtin_apply_args. */ 149 rtx x_apply_args_value; 150 151 /* List of labels that must never be deleted. */ 152 rtx x_forced_labels; 153 }; 154 155 #define pending_stack_adjust (cfun->expr->x_pending_stack_adjust) 156 #define inhibit_defer_pop (cfun->expr->x_inhibit_defer_pop) 157 #define saveregs_value (cfun->expr->x_saveregs_value) 158 #define apply_args_value (cfun->expr->x_apply_args_value) 159 #define forced_labels (cfun->expr->x_forced_labels) 160 #define stack_pointer_delta (cfun->expr->x_stack_pointer_delta) 161 162 struct temp_slot; 163 typedef struct temp_slot *temp_slot_p; 164 165 DEF_VEC_P(temp_slot_p); 166 DEF_VEC_ALLOC_P(temp_slot_p,gc); 167 168 enum function_frequency { 169 /* This function most likely won't be executed at all. 170 (set only when profile feedback is available). */ 171 FUNCTION_FREQUENCY_UNLIKELY_EXECUTED, 172 /* The default value. */ 173 FUNCTION_FREQUENCY_NORMAL, 174 /* Optimize this function hard 175 (set only when profile feedback is available). */ 176 FUNCTION_FREQUENCY_HOT 177 }; 178 179 /* This structure can save all the important global and static variables 180 describing the status of the current function. */ 181 182 struct function GTY(()) 183 { 184 struct eh_status *eh; 185 struct expr_status *expr; 186 struct emit_status *emit; 187 struct varasm_status *varasm; 188 189 /* The control flow graph for this function. */ 190 struct control_flow_graph *cfg; 191 192 /* For function.c. */ 193 194 /* Points to the FUNCTION_DECL of this function. */ 195 tree decl; 196 197 /* Function containing this function, if any. */ 198 struct function *outer; 199 200 /* Number of bytes of args popped by function being compiled on its return. 201 Zero if no bytes are to be popped. 202 May affect compilation of return insn or of function epilogue. */ 203 int pops_args; 204 205 /* If function's args have a fixed size, this is that size, in bytes. 206 Otherwise, it is -1. 207 May affect compilation of return insn or of function epilogue. */ 208 int args_size; 209 210 /* # bytes the prologue should push and pretend that the caller pushed them. 211 The prologue must do this, but only if parms can be passed in 212 registers. */ 213 int pretend_args_size; 214 215 /* # of bytes of outgoing arguments. If ACCUMULATE_OUTGOING_ARGS is 216 defined, the needed space is pushed by the prologue. */ 217 int outgoing_args_size; 218 219 /* This is the offset from the arg pointer to the place where the first 220 anonymous arg can be found, if there is one. */ 221 rtx arg_offset_rtx; 222 223 /* Quantities of various kinds of registers 224 used for the current function's args. */ 225 CUMULATIVE_ARGS args_info; 226 227 /* If nonzero, an RTL expression for the location at which the current 228 function returns its result. If the current function returns its 229 result in a register, current_function_return_rtx will always be 230 the hard register containing the result. */ 231 rtx return_rtx; 232 233 /* The arg pointer hard register, or the pseudo into which it was copied. */ 234 rtx internal_arg_pointer; 235 236 /* Opaque pointer used by get_hard_reg_initial_val and 237 has_hard_reg_initial_val (see integrate.[hc]). */ 238 struct initial_value_struct *hard_reg_initial_vals; 239 240 /* List (chain of EXPR_LIST) of labels heading the current handlers for 241 nonlocal gotos. */ 242 rtx x_nonlocal_goto_handler_labels; 243 244 /* Label that will go on function epilogue. 245 Jumping to this label serves as a "return" instruction 246 on machines which require execution of the epilogue on all returns. */ 247 rtx x_return_label; 248 249 /* Label that will go on the end of function epilogue. 250 Jumping to this label serves as a "naked return" instruction 251 on machines which require execution of the epilogue on all returns. */ 252 rtx x_naked_return_label; 253 254 /* List (chain of EXPR_LISTs) of all stack slots in this function. 255 Made for the sake of unshare_all_rtl. */ 256 rtx x_stack_slot_list; 257 258 /* Place after which to insert the tail_recursion_label if we need one. */ 259 rtx x_stack_check_probe_note; 260 261 /* Location at which to save the argument pointer if it will need to be 262 referenced. There are two cases where this is done: if nonlocal gotos 263 exist, or if vars stored at an offset from the argument pointer will be 264 needed by inner routines. */ 265 rtx x_arg_pointer_save_area; 266 267 /* Offset to end of allocated area of stack frame. 268 If stack grows down, this is the address of the last stack slot allocated. 269 If stack grows up, this is the address for the next slot. */ 270 HOST_WIDE_INT x_frame_offset; 271 272 /* A PARM_DECL that should contain the static chain for this function. 273 It will be initialized at the beginning of the function. */ 274 tree static_chain_decl; 275 276 /* An expression that contains the non-local goto save area. The first 277 word is the saved frame pointer and the second is the saved stack 278 pointer. */ 279 tree nonlocal_goto_save_area; 280 281 /* Insn after which register parms and SAVE_EXPRs are born, if nonopt. */ 282 rtx x_parm_birth_insn; 283 284 /* List of all used temporaries allocated, by level. */ 285 VEC(temp_slot_p,gc) *x_used_temp_slots; 286 287 /* List of available temp slots. */ 288 struct temp_slot *x_avail_temp_slots; 289 290 /* This slot is initialized as 0 and is added to 291 during the nested function. */ 292 struct var_refs_queue *fixup_var_refs_queue; 293 294 /* Current nesting level for temporaries. */ 295 int x_temp_slot_level; 296 297 /* Highest label number in current function. */ 298 int inl_max_label_num; 299 300 /* Function sequence number for profiling, debugging, etc. */ 301 int funcdef_no; 302 303 /* For flow.c. */ 304 305 /* Highest loop depth seen so far in loop analysis. Used in flow.c 306 for the "failure strategy" when doing liveness analysis starting 307 with non-empty initial sets. */ 308 int max_loop_depth; 309 310 /* For md files. */ 311 312 /* tm.h can use this to store whatever it likes. */ 313 struct machine_function * GTY ((maybe_undef)) machine; 314 315 /* The largest alignment of slot allocated on the stack. */ 316 unsigned int stack_alignment_needed; 317 318 /* Preferred alignment of the end of stack frame. */ 319 unsigned int preferred_stack_boundary; 320 321 /* Language-specific code can use this to store whatever it likes. */ 322 struct language_function * language; 323 324 /* Used types hash table. */ 325 htab_t GTY ((param_is (union tree_node))) used_types_hash; 326 327 /* For reorg. */ 328 329 /* If some insns can be deferred to the delay slots of the epilogue, the 330 delay list for them is recorded here. */ 331 rtx epilogue_delay_list; 332 333 /* Maximal number of entities in the single jumptable. Used to estimate 334 final flowgraph size. */ 335 int max_jumptable_ents; 336 337 /* UIDs for LABEL_DECLs. */ 338 int last_label_uid; 339 340 /* Line number of the end of the function. */ 341 location_t function_end_locus; 342 343 /* Array mapping insn uids to blocks. */ 344 VEC(tree,gc) *ib_boundaries_block; 345 346 /* The variables unexpanded so far. */ 347 tree unexpanded_var_list; 348 349 /* Assembly labels for the hot and cold text sections, to 350 be used by debugger functions for determining the size of text 351 sections. */ 352 353 const char *hot_section_label; 354 const char *cold_section_label; 355 const char *hot_section_end_label; 356 const char *cold_section_end_label; 357 358 /* String to be used for name of cold text sections, via 359 targetm.asm_out.named_section. */ 360 361 const char *unlikely_text_section_name; 362 363 /* A variable living at the top of the frame that holds a known value. 364 Used for detecting stack clobbers. */ 365 tree stack_protect_guard; 366 367 /* Collected bit flags. */ 368 369 /* Nonzero if function being compiled needs to be given an address 370 where the value should be stored. */ 371 unsigned int returns_struct : 1; 372 373 /* Nonzero if function being compiled needs to 374 return the address of where it has put a structure value. */ 375 unsigned int returns_pcc_struct : 1; 376 377 /* Nonzero if the current function returns a pointer type. */ 378 unsigned int returns_pointer : 1; 379 380 /* Nonzero if function being compiled can call setjmp. */ 381 unsigned int calls_setjmp : 1; 382 383 /* Nonzero if function being compiled can call alloca, 384 either as a subroutine or builtin. */ 385 unsigned int calls_alloca : 1; 386 387 /* Nonzero if function being compiled called builtin_return_addr or 388 builtin_frame_address with nonzero count. */ 389 unsigned int accesses_prior_frames : 1; 390 391 /* Nonzero if the function calls __builtin_eh_return. */ 392 unsigned int calls_eh_return : 1; 393 394 /* Nonzero if function being compiled receives nonlocal gotos 395 from nested functions. */ 396 unsigned int has_nonlocal_label : 1; 397 398 /* Nonzero if function being compiled has nonlocal gotos to parent 399 function. */ 400 unsigned int has_nonlocal_goto : 1; 401 402 /* Nonzero if the current function is a thunk, i.e., a lightweight 403 function implemented by the output_mi_thunk hook) that just 404 adjusts one of its arguments and forwards to another 405 function. */ 406 unsigned int is_thunk : 1; 407 408 /* This bit is used by the exception handling logic. It is set if all 409 calls (if any) are sibling calls. Such functions do not have to 410 have EH tables generated, as they cannot throw. A call to such a 411 function, however, should be treated as throwing if any of its callees 412 can throw. */ 413 unsigned int all_throwers_are_sibcalls : 1; 414 415 /* Nonzero if profiling code should be generated. */ 416 unsigned int profile : 1; 417 418 /* Nonzero if stack limit checking should be enabled in the current 419 function. */ 420 unsigned int limit_stack : 1; 421 422 /* Nonzero if current function uses stdarg.h or equivalent. */ 423 unsigned int stdarg : 1; 424 425 /* Nonzero if the back-end should not keep track of expressions that 426 determine the size of variable-sized objects. Normally, such 427 expressions are saved away, and then expanded when the next 428 function is started. For example, if a parameter has a 429 variable-sized type, then the size of the parameter is computed 430 when the function body is entered. However, some front-ends do 431 not desire this behavior. */ 432 unsigned int x_dont_save_pending_sizes_p : 1; 433 434 /* Nonzero if the current function uses the constant pool. */ 435 unsigned int uses_const_pool : 1; 436 437 /* Nonzero if the current function uses pic_offset_table_rtx. */ 438 unsigned int uses_pic_offset_table : 1; 439 440 /* Nonzero if the current function needs an lsda for exception handling. */ 441 unsigned int uses_eh_lsda : 1; 442 443 /* Nonzero if code to initialize arg_pointer_save_area has been emitted. */ 444 unsigned int arg_pointer_save_area_init : 1; 445 446 unsigned int after_inlining : 1; 447 448 /* Set when the call to function itself has been emit. */ 449 unsigned int recursive_call_emit : 1; 450 451 /* Set when the tail call has been produced. */ 452 unsigned int tail_call_emit : 1; 453 454 /* How commonly executed the function is. Initialized during branch 455 probabilities pass. */ 456 ENUM_BITFIELD (function_frequency) function_frequency : 2; 457 458 /* Number of units of general registers that need saving in stdarg 459 function. What unit is depends on the backend, either it is number 460 of bytes, or it can be number of registers. */ 461 unsigned int va_list_gpr_size : 8; 462 463 /* Number of units of floating point registers that need saving in stdarg 464 function. */ 465 unsigned int va_list_fpr_size : 8; 466 }; 467 468 /* If va_list_[gf]pr_size is set to this, it means we don't know how 469 many units need to be saved. */ 470 #define VA_LIST_MAX_GPR_SIZE 255 471 #define VA_LIST_MAX_FPR_SIZE 255 472 473 /* The function currently being compiled. */ 474 extern GTY(()) struct function *cfun; 475 476 /* Pointer to chain of `struct function' for containing functions. */ 477 extern GTY(()) struct function *outer_function_chain; 478 479 /* Nonzero if we've already converted virtual regs to hard regs. */ 480 extern int virtuals_instantiated; 481 482 /* Nonzero if at least one trampoline has been created. */ 483 extern int trampolines_created; 484 485 /* For backward compatibility... eventually these should all go away. */ 486 #define current_function_pops_args (cfun->pops_args) 487 #define current_function_returns_struct (cfun->returns_struct) 488 #define current_function_returns_pcc_struct (cfun->returns_pcc_struct) 489 #define current_function_returns_pointer (cfun->returns_pointer) 490 #define current_function_calls_setjmp (cfun->calls_setjmp) 491 #define current_function_calls_alloca (cfun->calls_alloca) 492 #define current_function_accesses_prior_frames (cfun->accesses_prior_frames) 493 #define current_function_calls_eh_return (cfun->calls_eh_return) 494 #define current_function_is_thunk (cfun->is_thunk) 495 #define current_function_args_info (cfun->args_info) 496 #define current_function_args_size (cfun->args_size) 497 #define current_function_pretend_args_size (cfun->pretend_args_size) 498 #define current_function_outgoing_args_size (cfun->outgoing_args_size) 499 #define current_function_arg_offset_rtx (cfun->arg_offset_rtx) 500 #define current_function_stdarg (cfun->stdarg) 501 #define current_function_internal_arg_pointer (cfun->internal_arg_pointer) 502 #define current_function_return_rtx (cfun->return_rtx) 503 #define current_function_profile (cfun->profile) 504 #define current_function_funcdef_no (cfun->funcdef_no) 505 #define current_function_limit_stack (cfun->limit_stack) 506 #define current_function_uses_pic_offset_table (cfun->uses_pic_offset_table) 507 #define current_function_uses_const_pool (cfun->uses_const_pool) 508 #define current_function_epilogue_delay_list (cfun->epilogue_delay_list) 509 #define current_function_has_nonlocal_label (cfun->has_nonlocal_label) 510 #define current_function_has_nonlocal_goto (cfun->has_nonlocal_goto) 511 512 #define return_label (cfun->x_return_label) 513 #define naked_return_label (cfun->x_naked_return_label) 514 #define stack_slot_list (cfun->x_stack_slot_list) 515 #define parm_birth_insn (cfun->x_parm_birth_insn) 516 #define frame_offset (cfun->x_frame_offset) 517 #define stack_check_probe_note (cfun->x_stack_check_probe_note) 518 #define arg_pointer_save_area (cfun->x_arg_pointer_save_area) 519 #define used_temp_slots (cfun->x_used_temp_slots) 520 #define avail_temp_slots (cfun->x_avail_temp_slots) 521 #define temp_slot_level (cfun->x_temp_slot_level) 522 #define nonlocal_goto_handler_labels (cfun->x_nonlocal_goto_handler_labels) 523 524 /* Given a function decl for a containing function, 525 return the `struct function' for it. */ 526 struct function *find_function_data (tree); 527 528 /* Identify BLOCKs referenced by more than one NOTE_INSN_BLOCK_{BEG,END}, 529 and create duplicate blocks. */ 530 extern void reorder_blocks (void); 531 532 /* Set BLOCK_NUMBER for all the blocks in FN. */ 533 extern void number_blocks (tree); 534 535 extern void clear_block_marks (tree); 536 extern tree blocks_nreverse (tree); 537 extern void reset_block_changes (void); 538 extern void record_block_change (tree); 539 extern void finalize_block_changes (void); 540 extern void check_block_change (rtx, tree *); 541 extern void free_block_changes (void); 542 543 /* Return size needed for stack frame based on slots so far allocated. 544 This size counts from zero. It is not rounded to STACK_BOUNDARY; 545 the caller may have to do that. */ 546 extern HOST_WIDE_INT get_frame_size (void); 547 548 /* Issue an error message and return TRUE if frame OFFSET overflows in 549 the signed target pointer arithmetics for function FUNC. Otherwise 550 return FALSE. */ 551 extern bool frame_offset_overflow (HOST_WIDE_INT, tree); 552 553 /* A pointer to a function to create target specific, per-function 554 data structures. */ 555 extern struct machine_function * (*init_machine_status) (void); 556 557 /* Save and restore status information for a nested function. */ 558 extern void free_after_parsing (struct function *); 559 extern void free_after_compilation (struct function *); 560 561 extern void init_varasm_status (struct function *); 562 563 #ifdef RTX_CODE 564 extern void diddle_return_value (void (*)(rtx, void*), void*); 565 extern void clobber_return_register (void); 566 #endif 567 568 extern rtx get_arg_pointer_save_area (struct function *); 569 570 /* Returns the name of the current function. */ 571 extern const char *current_function_name (void); 572 573 extern void do_warn_unused_parameter (tree); 574 575 extern bool pass_by_reference (CUMULATIVE_ARGS *, enum machine_mode, 576 tree, bool); 577 extern bool reference_callee_copied (CUMULATIVE_ARGS *, enum machine_mode, 578 tree, bool); 579 580 extern void used_types_insert (tree); 581 582 #endif /* GCC_FUNCTION_H */ 583