gas/config/tc-xtensa.h

   1 /* tc-xtensa.h -- Header file for tc-xtensa.c.
   2    Copyright (C) 2003, 2004, 2005, 2007 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 2, 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_ALIGN_NEXT_OPCODE,
  50   /* Use the first opcode of the next fragment to determine the
  51      alignment requirements.  This is ONLY used for LOOPs currently.  */
  52
  53   RELAX_CHECK_ALIGN_NEXT_OPCODE,
  54   /* The next non-empty frag contains a loop instruction.  Check to see
  55      if it is correctly aligned, but do not align it.  */
  56
  57   RELAX_DESIRE_ALIGN_IF_TARGET,
  58   /* These are placed in front of labels and converted to either
  59      RELAX_DESIRE_ALIGN / RELAX_LOOP_END or rs_fill of 0 before
  60      relaxation begins.  */
  61
  62   RELAX_ADD_NOP_IF_A0_B_RETW,
  63   /* These are placed in front of conditional branches.  Before
  64      relaxation begins, they are turned into either NOPs for branches
  65      immediately followed by RETW or RETW.N or rs_fills of 0.  This is
  66      used to avoid a hardware bug in some early versions of the
  67      processor.  */
  68
  69   RELAX_ADD_NOP_IF_PRE_LOOP_END,
  70   /* These are placed after JX instructions.  Before relaxation begins,
  71      they are turned into either NOPs, if the JX is one instruction
  72      before a loop end label, or rs_fills of 0.  This is used to avoid a
  73      hardware interlock issue prior to Xtensa version T1040.  */
  74
  75   RELAX_ADD_NOP_IF_SHORT_LOOP,
  76   /* These are placed after LOOP instructions and turned into NOPs when:
  77      (1) there are less than 3 instructions in the loop; we place 2 of
  78      these in a row to add up to 2 NOPS in short loops; or (2) the
  79      instructions in the loop do not include a branch or jump.
  80      Otherwise they are turned into rs_fills of 0 before relaxation
  81      begins.  This is used to avoid hardware bug PR3830.  */
  82
  83   RELAX_ADD_NOP_IF_CLOSE_LOOP_END,
  84   /* These are placed after LOOP instructions and turned into NOPs if
  85      there are less than 12 bytes to the end of some other loop's end.
  86      Otherwise they are turned into rs_fills of 0 before relaxation
  87      begins.  This is used to avoid hardware bug PR3830.  */
  88
  89   RELAX_DESIRE_ALIGN,
  90   /* The next fragment would like its first instruction to NOT cross an
  91      instruction fetch boundary.  */
  92
  93   RELAX_MAYBE_DESIRE_ALIGN,
  94   /* The next fragment might like its first instruction to NOT cross an
  95      instruction fetch boundary.  These are placed after a branch that
  96      might be relaxed.  If the branch is relaxed, then this frag will be
  97      a branch target and this frag will be changed to RELAX_DESIRE_ALIGN
  98      frag.  */
  99
 100   RELAX_LOOP_END,
 101   /* This will be turned into a NOP or NOP.N if the previous instruction
 102      is expanded to negate a loop.  */
 103
 104   RELAX_LOOP_END_ADD_NOP,
 105   /* When the code density option is available, this will generate a
 106      NOP.N marked RELAX_NARROW.  Otherwise, it will create an rs_fill
 107      fragment with a NOP in it.  */
 108
 109   RELAX_LITERAL,
 110   /* Another fragment could generate an expansion here but has not yet.  */
 111
 112   RELAX_LITERAL_NR,
 113   /* Expansion has been generated by an instruction that generates a
 114      literal.  However, the stretch has NOT been reported yet in this
 115      fragment.  */
 116
 117   RELAX_LITERAL_FINAL,
 118   /* Expansion has been generated by an instruction that generates a
 119      literal.  */
 120
 121   RELAX_LITERAL_POOL_BEGIN,
 122   RELAX_LITERAL_POOL_END,
 123   /* Technically these are not relaxations at all but mark a location
 124      to store literals later.  Note that fr_var stores the frchain for
 125      BEGIN frags and fr_var stores now_seg for END frags.  */
 126
 127   RELAX_NARROW,
 128   /* The last instruction in this fragment (at->fr_opcode) can be
 129      freely replaced with a single wider instruction if a future
 130      alignment desires or needs it.  */
 131
 132   RELAX_IMMED,
 133   /* The last instruction in this fragment (at->fr_opcode) contains
 134      the value defined by fr_symbol (fr_offset = 0).  If the value
 135      does not fit, use the specified expansion.  This is similar to
 136      "NARROW", except that these may not be expanded in order to align
 137      code.  */
 138
 139   RELAX_IMMED_STEP1,
 140   /* The last instruction in this fragment (at->fr_opcode) contains a
 141      literal.  It has already been expanded at least 1 step.  */
 142
 143   RELAX_IMMED_STEP2,
 144   /* The last instruction in this fragment (at->fr_opcode) contains a
 145      literal.  It has already been expanded at least 2 steps.  */
 146
 147   RELAX_SLOTS,
 148   /* There are instructions within the last VLIW instruction that need
 149      relaxation.  Find the relaxation based on the slot info in
 150      xtensa_frag_type.  Relaxations that deal with particular opcodes
 151      are slot-based (e.g., converting a MOVI to an L32R).  Relaxations
 152      that deal with entire instructions, such as alignment, are not
 153      slot-based.  */
 154
 155   RELAX_FILL_NOP,
 156   /* This marks the location of a pipeline stall.  We can fill these guys
 157      in for alignment of any size.  */
 158
 159   RELAX_UNREACHABLE,
 160   /* This marks the location as unreachable.  The assembler may widen or
 161      narrow this area to meet alignment requirements of nearby
 162      instructions.  */
 163
 164   RELAX_MAYBE_UNREACHABLE,
 165   /* This marks the location as possibly unreachable.  These are placed
 166      after a branch that may be relaxed into a branch and jump. If the
 167      branch is relaxed, then this frag will be converted to a
 168      RELAX_UNREACHABLE frag.  */
 169
 170   RELAX_ORG,
 171   /* This marks the location as having previously been an rs_org frag.
 172      rs_org frags are converted to fill-zero frags immediately after
 173      relaxation.  However, we need to remember where they were so we can
 174      prevent the linker from changing the size of any frag between the
 175      section start and the org frag.  */
 176
 177   RELAX_NONE
 178 };
 179
 180 /* This is used as a stopper to bound the number of steps that
 181    can be taken.  */
 182 #define RELAX_IMMED_MAXSTEPS (RELAX_IMMED_STEP2 - RELAX_IMMED)
 183
 184 struct xtensa_frag_type
 185 {
 186   /* Info about the current state of assembly, e.g., transform,
 187      absolute_literals, etc.  These need to be passed to the backend and
 188      then to the object file.
 189
 190      When is_assembly_state_set is false, the frag inherits some of the
 191      state settings from the previous frag in this segment.  Because it
 192      is not possible to intercept all fragment closures (frag_more and
 193      frag_append_1_char can close a frag), we use a pass after initial
 194      assembly to fill in the assembly states.  */
 195
 196   unsigned int is_assembly_state_set : 1;
 197   unsigned int is_no_density : 1;
 198   unsigned int is_no_transform : 1;
 199   unsigned int use_longcalls : 1;
 200   unsigned int use_absolute_literals : 1;
 201
 202   /* Inhibits relaxation of machine-dependent alignment frags the
 203      first time through a relaxation....  */
 204   unsigned int relax_seen : 1;
 205
 206   /* Information that is needed in the object file and set when known.  */
 207   unsigned int is_literal : 1;
 208   unsigned int is_loop_target : 1;
 209   unsigned int is_branch_target : 1;
 210   unsigned int is_insn : 1;
 211   unsigned int is_unreachable : 1;
 212
 213   unsigned int is_specific_opcode : 1; /* also implies no_transform */
 214
 215   unsigned int is_align : 1;
 216   unsigned int is_text_align : 1;
 217   unsigned int alignment : 5;
 218
 219   /* A frag with this bit set is the first in a loop that actually
 220      contains an instruction.  */
 221   unsigned int is_first_loop_insn : 1;
 222
 223   /* A frag with this bit set is a branch that we are using to
 224      align branch targets as if it were a normal narrow instruction.  */
 225   unsigned int is_aligning_branch : 1;
 226
 227   /* For text fragments that can generate literals at relax time, this
 228      variable points to the frag where the literal will be stored.  For
 229      literal frags, this variable points to the nearest literal pool
 230      location frag.  This literal frag will be moved to after this
 231      location.  For RELAX_LITERAL_POOL_BEGIN frags, this field points
 232      to the frag immediately before the corresponding RELAX_LITERAL_POOL_END
 233      frag, to make moving frags for this literal pool efficient.  */
 234   fragS *literal_frag;
 235
 236   /* The destination segment for literal frags.  (Note that this is only
 237      valid after xtensa_move_literals.)  This field is also used for
 238      LITERAL_POOL_END frags.  */
 239   segT lit_seg;
 240
 241   /* Frag chain for LITERAL_POOL_BEGIN frags.  */
 242   struct frchain *lit_frchain;
 243
 244   /* For the relaxation scheme, some literal fragments can have their
 245      expansions modified by an instruction that relaxes.  */
 246   int text_expansion[MAX_SLOTS];
 247   int literal_expansion[MAX_SLOTS];
 248   int unreported_expansion;
 249
 250   /* For text fragments that can generate literals at relax time:  */
 251   fragS *literal_frags[MAX_SLOTS];
 252   enum xtensa_relax_statesE slot_subtypes[MAX_SLOTS];
 253   symbolS *slot_symbols[MAX_SLOTS];
 254   offsetT slot_offsets[MAX_SLOTS];
 255
 256   /* The global aligner needs to walk backward through the list of
 257      frags.  This field is only valid after xtensa_end.  */
 258   fragS *fr_prev;
 259 };
 260
 261
 262 /* For VLIW support, we need to know what slot a fixup applies to.  */
 263 typedef struct xtensa_fix_data_struct
 264 {
 265   int slot;
 266   symbolS *X_add_symbol;
 267   offsetT X_add_number;
 268 } xtensa_fix_data;
 269
 270
 271 /* Structure to record xtensa-specific symbol information.  */
 272 typedef struct xtensa_symfield_type
 273 {
 274   unsigned int is_loop_target : 1;
 275   unsigned int is_branch_target : 1;
 276 } xtensa_symfield_type;
 277
 278
 279 /* Structure for saving information about a block of property data
 280    for frags that have the same flags.   The forward reference is
 281    in this header file.  The actual definition is in tc-xtensa.c.  */
 282 struct xtensa_block_info_struct;
 283 typedef struct xtensa_block_info_struct xtensa_block_info;
 284
 285
 286 /* Property section types.  */
 287 typedef enum
 288 {
 289   xt_literal_sec,
 290   xt_prop_sec,
 291   max_xt_sec
 292 } xt_section_type;
 293
 294 typedef struct xtensa_segment_info_struct
 295 {
 296   fragS *literal_pool_loc;
 297   xtensa_block_info *blocks[max_xt_sec];
 298 } xtensa_segment_info;
 299
 300
 301 extern const char *xtensa_target_format (void);
 302 extern void xtensa_init_fix_data (struct fix *);
 303 extern void xtensa_frag_init (fragS *);
 304 extern int xtensa_force_relocation (struct fix *);
 305 extern int xtensa_validate_fix_sub (struct fix *);
 306 extern void xtensa_frob_label (struct symbol *);
 307 extern void xtensa_end (void);
 308 extern void xtensa_post_relax_hook (void);
 309 extern void xtensa_file_arch_init (bfd *);
 310 extern void xtensa_flush_pending_output (void);
 311 extern bfd_boolean xtensa_fix_adjustable (struct fix *);
 312 extern void xtensa_symbol_new_hook (symbolS *);
 313 extern long xtensa_relax_frag (fragS *, long, int *);
 314 extern void xtensa_elf_section_change_hook (void);
 315 extern int xtensa_unrecognized_line (int);
 316 extern bfd_boolean xtensa_check_inside_bundle (void);
 317 extern void xtensa_handle_align (fragS *);
 318 extern char *xtensa_section_rename (char *);
 319
 320 #define TARGET_FORMAT                   xtensa_target_format ()
 321 #define TARGET_ARCH                     bfd_arch_xtensa
 322 #define TC_SEGMENT_INFO_TYPE            xtensa_segment_info
 323 #define TC_SYMFIELD_TYPE                struct xtensa_symfield_type
 324 #define TC_FIX_TYPE                     xtensa_fix_data
 325 #define TC_INIT_FIX_DATA(x)             xtensa_init_fix_data (x)
 326 #define TC_FRAG_TYPE                    struct xtensa_frag_type
 327 #define TC_FRAG_INIT(frag)              xtensa_frag_init (frag)
 328 #define TC_FORCE_RELOCATION(fix)        xtensa_force_relocation (fix)
 329 #define TC_FORCE_RELOCATION_SUB_SAME(fix, seg) \
 330   (! SEG_NORMAL (seg) || xtensa_force_relocation (fix))
 331 #define TC_VALIDATE_FIX_SUB(fix)        xtensa_validate_fix_sub (fix)
 332 #define NO_PSEUDO_DOT                   xtensa_check_inside_bundle ()
 333 #define tc_canonicalize_symbol_name(s)  xtensa_section_rename (s)
 334 #define tc_canonicalize_section_name(s) xtensa_section_rename (s)
 335 #define tc_init_after_args()            xtensa_file_arch_init (stdoutput)
 336 #define tc_fix_adjustable(fix)          xtensa_fix_adjustable (fix)
 337 #define tc_frob_label(sym)              xtensa_frob_label (sym)
 338 #define tc_unrecognized_line(ch)        xtensa_unrecognized_line (ch)
 339 #define md_do_align(a,b,c,d,e)          xtensa_flush_pending_output ()
 340 #define md_elf_section_change_hook      xtensa_elf_section_change_hook
 341 #define md_end                          xtensa_end
 342 #define md_flush_pending_output()       xtensa_flush_pending_output ()
 343 #define md_operand(x)
 344 #define TEXT_SECTION_NAME               xtensa_section_rename (".text")
 345 #define DATA_SECTION_NAME               xtensa_section_rename (".data")
 346 #define BSS_SECTION_NAME                xtensa_section_rename (".bss")
 347 #define HANDLE_ALIGN(fragP)             xtensa_handle_align (fragP)
 348 #define MAX_MEM_FOR_RS_ALIGN_CODE       1
 349
 350
 351 /* The renumber_section function must be mapped over all the sections
 352    after calling xtensa_post_relax_hook.  That function is static in
 353    write.c so it cannot be called from xtensa_post_relax_hook itself.  */
 354
 355 #define md_post_relax_hook \
 356   do \
 357     { \
 358       int i = 0; \
 359       xtensa_post_relax_hook (); \
 360       bfd_map_over_sections (stdoutput, renumber_sections, &i); \
 361     } \
 362   while (0)
 363
 364
 365 /* Because xtensa relaxation can insert a new literal into the middle of
 366    fragment and thus require re-running the relaxation pass on the
 367    section, we need an explicit flag here.  We explicitly use the name
 368    "stretched" here to avoid changing the source code in write.c.  */
 369
 370 #define md_relax_frag(segment, fragP, stretch) \
 371   xtensa_relax_frag (fragP, stretch, &stretched)
 372
 373
 374 #define LOCAL_LABELS_FB 1
 375 #define WORKING_DOT_WORD 1
 376 #define DOUBLESLASH_LINE_COMMENTS
 377 #define TC_HANDLES_FX_DONE
 378 #define TC_FINALIZE_SYMS_BEFORE_SIZE_SEG 0
 379 #define TC_LINKRELAX_FIXUP(SEG) 0
 380 #define MD_APPLY_SYM_VALUE(FIX) 0
 381 #define SUB_SEGMENT_ALIGN(SEG, FRCHAIN) 0
 382
 383 /* Use line number format that is amenable to linker relaxation.  */
 384 #define DWARF2_USE_FIXED_ADVANCE_PC (linkrelax != 0)
 385
 386
 387 /* Resource reservation info functions.  */
 388
 389 /* Returns the number of copies of a particular unit.  */
 390 typedef int (*unit_num_copies_func) (void *, xtensa_funcUnit);
 391
 392 /* Returns the number of units the opcode uses.  */
 393 typedef int (*opcode_num_units_func) (void *, xtensa_opcode);
 394
 395 /* Given an opcode and an index into the opcode's funcUnit list,
 396    returns the unit used for the index.  */
 397 typedef int (*opcode_funcUnit_use_unit_func) (void *, xtensa_opcode, int);
 398
 399 /* Given an opcode and an index into the opcode's funcUnit list,
 400    returns the cycle during which the unit is used.  */
 401 typedef int (*opcode_funcUnit_use_stage_func) (void *, xtensa_opcode, int);
 402
 403 /* The above typedefs parameterize the resource_table so that the
 404    optional scheduler doesn't need its own resource reservation system.
 405
 406    For simple resource checking, which is all that happens normally,
 407    the functions will be as follows (with some wrapping to make the
 408    interface more convenient):
 409
 410    unit_num_copies_func = xtensa_funcUnit_num_copies
 411    opcode_num_units_func = xtensa_opcode_num_funcUnit_uses
 412    opcode_funcUnit_use_unit_func = xtensa_opcode_funcUnit_use->unit
 413    opcode_funcUnit_use_stage_func = xtensa_opcode_funcUnit_use->stage
 414
 415    Of course the optional scheduler has its own reservation table
 416    and functions.  */
 417
 418 int opcode_funcUnit_use_unit (void *, xtensa_opcode, int);
 419 int opcode_funcUnit_use_stage (void *, xtensa_opcode, int);
 420
 421 typedef struct
 422 {
 423   void *data;
 424   int cycles;
 425   int allocated_cycles;
 426   int num_units;
 427   unit_num_copies_func unit_num_copies;
 428   opcode_num_units_func opcode_num_units;
 429   opcode_funcUnit_use_unit_func opcode_unit_use;
 430   opcode_funcUnit_use_stage_func opcode_unit_stage;
 431   unsigned char **units;
 432 } resource_table;
 433
 434 resource_table *new_resource_table
 435   (void *, int, int, unit_num_copies_func, opcode_num_units_func,
 436    opcode_funcUnit_use_unit_func, opcode_funcUnit_use_stage_func);
 437 void resize_resource_table (resource_table *, int);
 438 void clear_resource_table (resource_table *);
 439 bfd_boolean resources_available (resource_table *, xtensa_opcode, int);
 440 void reserve_resources (resource_table *, xtensa_opcode, int);
 441 void release_resources (resource_table *, xtensa_opcode, int);
 442
 443 #endif /* TC_XTENSA */