1 /* tc-xtensa.h -- Header file for tc-xtensa.c. 2 Copyright (C) 2003-2014 Free Software Foundation, Inc. 3 4 This file is part of GAS, the GNU Assembler. 5 6 GAS is free software; you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by 8 the Free Software Foundation; either version 3, or (at your option) 9 any later version. 10 11 GAS is distributed in the hope that it will be useful, 12 but WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 GNU General Public License for more details. 15 16 You should have received a copy of the GNU General Public License 17 along with GAS; see the file COPYING. If not, write to the Free 18 Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA 19 02110-1301, USA. */ 20 21 #ifndef TC_XTENSA 22 #define TC_XTENSA 1 23 24 struct fix; 25 26 #ifndef OBJ_ELF 27 #error Xtensa support requires ELF object format 28 #endif 29 30 #include "xtensa-isa.h" 31 #include "xtensa-config.h" 32 33 #define TARGET_BYTES_BIG_ENDIAN XCHAL_HAVE_BE 34 35 36 /* Maximum number of opcode slots in a VLIW instruction. */ 37 #define MAX_SLOTS 15 38 39 40 /* For all xtensa relax states except RELAX_DESIRE_ALIGN and 41 RELAX_DESIRE_ALIGN_IF_TARGET, the amount a frag might grow is stored 42 in the fr_var field. For the two exceptions, fr_var is a float value 43 that records the frequency with which the following instruction is 44 executed as a branch target. The aligner uses this information to 45 tell which targets are most important to be aligned. */ 46 47 enum xtensa_relax_statesE 48 { 49 RELAX_XTENSA_NONE, 50 51 RELAX_ALIGN_NEXT_OPCODE, 52 /* Use the first opcode of the next fragment to determine the 53 alignment requirements. This is ONLY used for LOOPs currently. */ 54 55 RELAX_CHECK_ALIGN_NEXT_OPCODE, 56 /* The next non-empty frag contains a loop instruction. Check to see 57 if it is correctly aligned, but do not align it. */ 58 59 RELAX_DESIRE_ALIGN_IF_TARGET, 60 /* These are placed in front of labels and converted to either 61 RELAX_DESIRE_ALIGN / RELAX_LOOP_END or rs_fill of 0 before 62 relaxation begins. */ 63 64 RELAX_ADD_NOP_IF_A0_B_RETW, 65 /* These are placed in front of conditional branches. Before 66 relaxation begins, they are turned into either NOPs for branches 67 immediately followed by RETW or RETW.N or rs_fills of 0. This is 68 used to avoid a hardware bug in some early versions of the 69 processor. */ 70 71 RELAX_ADD_NOP_IF_PRE_LOOP_END, 72 /* These are placed after JX instructions. Before relaxation begins, 73 they are turned into either NOPs, if the JX is one instruction 74 before a loop end label, or rs_fills of 0. This is used to avoid a 75 hardware interlock issue prior to Xtensa version T1040. */ 76 77 RELAX_ADD_NOP_IF_SHORT_LOOP, 78 /* These are placed after LOOP instructions and turned into NOPs when: 79 (1) there are less than 3 instructions in the loop; we place 2 of 80 these in a row to add up to 2 NOPS in short loops; or (2) the 81 instructions in the loop do not include a branch or jump. 82 Otherwise they are turned into rs_fills of 0 before relaxation 83 begins. This is used to avoid hardware bug PR3830. */ 84 85 RELAX_ADD_NOP_IF_CLOSE_LOOP_END, 86 /* These are placed after LOOP instructions and turned into NOPs if 87 there are less than 12 bytes to the end of some other loop's end. 88 Otherwise they are turned into rs_fills of 0 before relaxation 89 begins. This is used to avoid hardware bug PR3830. */ 90 91 RELAX_DESIRE_ALIGN, 92 /* The next fragment would like its first instruction to NOT cross an 93 instruction fetch boundary. */ 94 95 RELAX_MAYBE_DESIRE_ALIGN, 96 /* The next fragment might like its first instruction to NOT cross an 97 instruction fetch boundary. These are placed after a branch that 98 might be relaxed. If the branch is relaxed, then this frag will be 99 a branch target and this frag will be changed to RELAX_DESIRE_ALIGN 100 frag. */ 101 102 RELAX_LOOP_END, 103 /* This will be turned into a NOP or NOP.N if the previous instruction 104 is expanded to negate a loop. */ 105 106 RELAX_LOOP_END_ADD_NOP, 107 /* When the code density option is available, this will generate a 108 NOP.N marked RELAX_NARROW. Otherwise, it will create an rs_fill 109 fragment with a NOP in it. Once a frag has been converted to 110 RELAX_LOOP_END_ADD_NOP, it should never be changed back to 111 RELAX_LOOP_END. */ 112 113 RELAX_LITERAL, 114 /* Another fragment could generate an expansion here but has not yet. */ 115 116 RELAX_LITERAL_NR, 117 /* Expansion has been generated by an instruction that generates a 118 literal. However, the stretch has NOT been reported yet in this 119 fragment. */ 120 121 RELAX_LITERAL_FINAL, 122 /* Expansion has been generated by an instruction that generates a 123 literal. */ 124 125 RELAX_LITERAL_POOL_BEGIN, 126 RELAX_LITERAL_POOL_END, 127 /* Technically these are not relaxations at all but mark a location 128 to store literals later. Note that fr_var stores the frchain for 129 BEGIN frags and fr_var stores now_seg for END frags. */ 130 131 RELAX_NARROW, 132 /* The last instruction in this fragment (at->fr_opcode) can be 133 freely replaced with a single wider instruction if a future 134 alignment desires or needs it. */ 135 136 RELAX_IMMED, 137 /* The last instruction in this fragment (at->fr_opcode) contains 138 an immediate or symbol. If the value does not fit, relax the 139 opcode using expansions from the relax table. */ 140 141 RELAX_IMMED_STEP1, 142 /* The last instruction in this fragment (at->fr_opcode) contains a 143 literal. It has already been expanded 1 step. */ 144 145 RELAX_IMMED_STEP2, 146 /* The last instruction in this fragment (at->fr_opcode) contains a 147 literal. It has already been expanded 2 steps. */ 148 149 RELAX_IMMED_STEP3, 150 /* The last instruction in this fragment (at->fr_opcode) contains a 151 literal. It has already been expanded 3 steps. */ 152 153 RELAX_SLOTS, 154 /* There are instructions within the last VLIW instruction that need 155 relaxation. Find the relaxation based on the slot info in 156 xtensa_frag_type. Relaxations that deal with particular opcodes 157 are slot-based (e.g., converting a MOVI to an L32R). Relaxations 158 that deal with entire instructions, such as alignment, are not 159 slot-based. */ 160 161 RELAX_FILL_NOP, 162 /* This marks the location of a pipeline stall. We can fill these guys 163 in for alignment of any size. */ 164 165 RELAX_UNREACHABLE, 166 /* This marks the location as unreachable. The assembler may widen or 167 narrow this area to meet alignment requirements of nearby 168 instructions. */ 169 170 RELAX_MAYBE_UNREACHABLE, 171 /* This marks the location as possibly unreachable. These are placed 172 after a branch that may be relaxed into a branch and jump. If the 173 branch is relaxed, then this frag will be converted to a 174 RELAX_UNREACHABLE frag. */ 175 176 RELAX_ORG, 177 /* This marks the location as having previously been an rs_org frag. 178 rs_org frags are converted to fill-zero frags immediately after 179 relaxation. However, we need to remember where they were so we can 180 prevent the linker from changing the size of any frag between the 181 section start and the org frag. */ 182 183 RELAX_TRAMPOLINE, 184 /* Every few thousand frags, we insert one of these, just in case we may 185 need some space for a trampoline (jump to a jump) because the function 186 has gotten too big. If not needed, it disappears. */ 187 188 RELAX_NONE 189 }; 190 191 /* This is used as a stopper to bound the number of steps that 192 can be taken. */ 193 #define RELAX_IMMED_MAXSTEPS (RELAX_IMMED_STEP3 - RELAX_IMMED) 194 195 struct xtensa_frag_type 196 { 197 /* Info about the current state of assembly, e.g., transform, 198 absolute_literals, etc. These need to be passed to the backend and 199 then to the object file. 200 201 When is_assembly_state_set is false, the frag inherits some of the 202 state settings from the previous frag in this segment. Because it 203 is not possible to intercept all fragment closures (frag_more and 204 frag_append_1_char can close a frag), we use a pass after initial 205 assembly to fill in the assembly states. */ 206 207 unsigned int is_assembly_state_set : 1; 208 unsigned int is_no_density : 1; 209 unsigned int is_no_transform : 1; 210 unsigned int use_longcalls : 1; 211 unsigned int use_absolute_literals : 1; 212 213 /* Inhibits relaxation of machine-dependent alignment frags the 214 first time through a relaxation.... */ 215 unsigned int relax_seen : 1; 216 217 /* Information that is needed in the object file and set when known. */ 218 unsigned int is_literal : 1; 219 unsigned int is_loop_target : 1; 220 unsigned int is_branch_target : 1; 221 unsigned int is_insn : 1; 222 unsigned int is_unreachable : 1; 223 224 unsigned int is_specific_opcode : 1; /* also implies no_transform */ 225 226 unsigned int is_align : 1; 227 unsigned int is_text_align : 1; 228 unsigned int alignment : 5; 229 230 /* A frag with this bit set is the first in a loop that actually 231 contains an instruction. */ 232 unsigned int is_first_loop_insn : 1; 233 234 /* A frag with this bit set is a branch that we are using to 235 align branch targets as if it were a normal narrow instruction. */ 236 unsigned int is_aligning_branch : 1; 237 238 /* For text fragments that can generate literals at relax time, this 239 variable points to the frag where the literal will be stored. For 240 literal frags, this variable points to the nearest literal pool 241 location frag. This literal frag will be moved to after this 242 location. For RELAX_LITERAL_POOL_BEGIN frags, this field points 243 to the frag immediately before the corresponding RELAX_LITERAL_POOL_END 244 frag, to make moving frags for this literal pool efficient. */ 245 fragS *literal_frag; 246 247 /* The destination segment for literal frags. (Note that this is only 248 valid after xtensa_move_literals.) This field is also used for 249 LITERAL_POOL_END frags. */ 250 segT lit_seg; 251 252 /* Frag chain for LITERAL_POOL_BEGIN frags. */ 253 struct frchain *lit_frchain; 254 255 /* For the relaxation scheme, some literal fragments can have their 256 expansions modified by an instruction that relaxes. */ 257 int text_expansion[MAX_SLOTS]; 258 int literal_expansion[MAX_SLOTS]; 259 int unreported_expansion; 260 261 /* For slots that have a free register for relaxation, record that 262 register. */ 263 expressionS free_reg[MAX_SLOTS]; 264 265 /* For text fragments that can generate literals at relax time: */ 266 fragS *literal_frags[MAX_SLOTS]; 267 enum xtensa_relax_statesE slot_subtypes[MAX_SLOTS]; 268 symbolS *slot_symbols[MAX_SLOTS]; 269 offsetT slot_offsets[MAX_SLOTS]; 270 271 /* When marking frags after this one in the chain as no transform, 272 cache the last one in the chain, so that we can skip to the 273 end of the chain. */ 274 fragS *no_transform_end; 275 }; 276 277 278 /* For VLIW support, we need to know what slot a fixup applies to. */ 279 typedef struct xtensa_fix_data_struct 280 { 281 int slot; 282 symbolS *X_add_symbol; 283 offsetT X_add_number; 284 } xtensa_fix_data; 285 286 287 /* Structure to record xtensa-specific symbol information. */ 288 typedef struct xtensa_symfield_type 289 { 290 unsigned int is_loop_target : 1; 291 unsigned int is_branch_target : 1; 292 symbolS *next_expr_symbol; 293 } xtensa_symfield_type; 294 295 296 /* Structure for saving information about a block of property data 297 for frags that have the same flags. The forward reference is 298 in this header file. The actual definition is in tc-xtensa.c. */ 299 struct xtensa_block_info_struct; 300 typedef struct xtensa_block_info_struct xtensa_block_info; 301 302 303 /* Property section types. */ 304 typedef enum 305 { 306 xt_literal_sec, 307 xt_prop_sec, 308 max_xt_sec 309 } xt_section_type; 310 311 typedef struct xtensa_segment_info_struct 312 { 313 fragS *literal_pool_loc; 314 xtensa_block_info *blocks[max_xt_sec]; 315 } xtensa_segment_info; 316 317 318 extern const char *xtensa_target_format (void); 319 extern void xtensa_init_fix_data (struct fix *); 320 extern void xtensa_frag_init (fragS *); 321 extern int xtensa_force_relocation (struct fix *); 322 extern int xtensa_validate_fix_sub (struct fix *); 323 extern void xtensa_frob_label (struct symbol *); 324 extern void xtensa_end (void); 325 extern void xtensa_post_relax_hook (void); 326 extern void xtensa_file_arch_init (bfd *); 327 extern void xtensa_flush_pending_output (void); 328 extern bfd_boolean xtensa_fix_adjustable (struct fix *); 329 extern void xtensa_symbol_new_hook (symbolS *); 330 extern long xtensa_relax_frag (fragS *, long, int *); 331 extern void xtensa_elf_section_change_hook (void); 332 extern int xtensa_unrecognized_line (int); 333 extern bfd_boolean xtensa_check_inside_bundle (void); 334 extern void xtensa_handle_align (fragS *); 335 extern char *xtensa_section_rename (char *); 336 337 #define TARGET_FORMAT xtensa_target_format () 338 #define TARGET_ARCH bfd_arch_xtensa 339 #define TC_SEGMENT_INFO_TYPE xtensa_segment_info 340 #define TC_SYMFIELD_TYPE struct xtensa_symfield_type 341 #define TC_FIX_TYPE xtensa_fix_data 342 #define TC_INIT_FIX_DATA(x) xtensa_init_fix_data (x) 343 #define TC_FRAG_TYPE struct xtensa_frag_type 344 #define TC_FRAG_INIT(frag) xtensa_frag_init (frag) 345 #define TC_FORCE_RELOCATION(fix) xtensa_force_relocation (fix) 346 #define TC_FORCE_RELOCATION_SUB_SAME(fix, seg) \ 347 (! SEG_NORMAL (seg) || xtensa_force_relocation (fix)) 348 #define TC_VALIDATE_FIX_SUB(fix, seg) xtensa_validate_fix_sub (fix) 349 #define NO_PSEUDO_DOT xtensa_check_inside_bundle () 350 #define tc_canonicalize_symbol_name(s) xtensa_section_rename (s) 351 #define tc_canonicalize_section_name(s) xtensa_section_rename (s) 352 #define tc_init_after_args() xtensa_file_arch_init (stdoutput) 353 #define tc_fix_adjustable(fix) xtensa_fix_adjustable (fix) 354 #define tc_frob_label(sym) xtensa_frob_label (sym) 355 #define tc_unrecognized_line(ch) xtensa_unrecognized_line (ch) 356 #define tc_symbol_new_hook(sym) xtensa_symbol_new_hook (sym) 357 #define md_do_align(a,b,c,d,e) xtensa_flush_pending_output () 358 #define md_elf_section_change_hook xtensa_elf_section_change_hook 359 #define md_end xtensa_end 360 #define md_flush_pending_output() xtensa_flush_pending_output () 361 #define md_operand(x) 362 #define TEXT_SECTION_NAME xtensa_section_rename (".text") 363 #define DATA_SECTION_NAME xtensa_section_rename (".data") 364 #define BSS_SECTION_NAME xtensa_section_rename (".bss") 365 #define HANDLE_ALIGN(fragP) xtensa_handle_align (fragP) 366 #define MAX_MEM_FOR_RS_ALIGN_CODE 1 367 368 369 /* The renumber_section function must be mapped over all the sections 370 after calling xtensa_post_relax_hook. That function is static in 371 write.c so it cannot be called from xtensa_post_relax_hook itself. */ 372 373 #define md_post_relax_hook \ 374 do \ 375 { \ 376 int i = 0; \ 377 xtensa_post_relax_hook (); \ 378 bfd_map_over_sections (stdoutput, renumber_sections, &i); \ 379 } \ 380 while (0) 381 382 383 /* Because xtensa relaxation can insert a new literal into the middle of 384 fragment and thus require re-running the relaxation pass on the 385 section, we need an explicit flag here. We explicitly use the name 386 "stretched" here to avoid changing the source code in write.c. */ 387 388 #define md_relax_frag(segment, fragP, stretch) \ 389 xtensa_relax_frag (fragP, stretch, &stretched) 390 391 /* Only allow call frame debug info optimization when linker relaxation is 392 not enabled as otherwise we could generate the DWARF directives without 393 the relocs necessary to patch them up. */ 394 #define md_allow_eh_opt (linkrelax == 0) 395 396 #define LOCAL_LABELS_FB 1 397 #define WORKING_DOT_WORD 1 398 #define DOUBLESLASH_LINE_COMMENTS 399 #define TC_HANDLES_FX_DONE 400 #define TC_FINALIZE_SYMS_BEFORE_SIZE_SEG 0 401 #define TC_LINKRELAX_FIXUP(SEG) 0 402 #define MD_APPLY_SYM_VALUE(FIX) 0 403 #define SUB_SEGMENT_ALIGN(SEG, FRCHAIN) 0 404 405 /* Use line number format that is amenable to linker relaxation. */ 406 #define DWARF2_USE_FIXED_ADVANCE_PC (linkrelax != 0) 407 408 409 /* Resource reservation info functions. */ 410 411 /* Returns the number of copies of a particular unit. */ 412 typedef int (*unit_num_copies_func) (void *, xtensa_funcUnit); 413 414 /* Returns the number of units the opcode uses. */ 415 typedef int (*opcode_num_units_func) (void *, xtensa_opcode); 416 417 /* Given an opcode and an index into the opcode's funcUnit list, 418 returns the unit used for the index. */ 419 typedef int (*opcode_funcUnit_use_unit_func) (void *, xtensa_opcode, int); 420 421 /* Given an opcode and an index into the opcode's funcUnit list, 422 returns the cycle during which the unit is used. */ 423 typedef int (*opcode_funcUnit_use_stage_func) (void *, xtensa_opcode, int); 424 425 /* The above typedefs parameterize the resource_table so that the 426 optional scheduler doesn't need its own resource reservation system. 427 428 For simple resource checking, which is all that happens normally, 429 the functions will be as follows (with some wrapping to make the 430 interface more convenient): 431 432 unit_num_copies_func = xtensa_funcUnit_num_copies 433 opcode_num_units_func = xtensa_opcode_num_funcUnit_uses 434 opcode_funcUnit_use_unit_func = xtensa_opcode_funcUnit_use->unit 435 opcode_funcUnit_use_stage_func = xtensa_opcode_funcUnit_use->stage 436 437 Of course the optional scheduler has its own reservation table 438 and functions. */ 439 440 int opcode_funcUnit_use_unit (void *, xtensa_opcode, int); 441 int opcode_funcUnit_use_stage (void *, xtensa_opcode, int); 442 443 typedef struct 444 { 445 void *data; 446 int cycles; 447 int allocated_cycles; 448 int num_units; 449 unit_num_copies_func unit_num_copies; 450 opcode_num_units_func opcode_num_units; 451 opcode_funcUnit_use_unit_func opcode_unit_use; 452 opcode_funcUnit_use_stage_func opcode_unit_stage; 453 unsigned char **units; 454 } resource_table; 455 456 resource_table *new_resource_table 457 (void *, int, int, unit_num_copies_func, opcode_num_units_func, 458 opcode_funcUnit_use_unit_func, opcode_funcUnit_use_stage_func); 459 void resize_resource_table (resource_table *, int); 460 void clear_resource_table (resource_table *); 461 bfd_boolean resources_available (resource_table *, xtensa_opcode, int); 462 void reserve_resources (resource_table *, xtensa_opcode, int); 463 void release_resources (resource_table *, xtensa_opcode, int); 464 465 #endif /* TC_XTENSA */ 466
