1 /* tc-xtensa.h -- Header file for tc-xtensa.c.
2 Copyright (C) 2003, 2004, 2005, 2007 Free Software Foundation, Inc.
4 This file is part of GAS, the GNU Assembler.
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)
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.
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
27 #error Xtensa support requires ELF object format
30 #include "xtensa-isa.h"
31 #include "xtensa-config.h"
33 #define TARGET_BYTES_BIG_ENDIAN XCHAL_HAVE_BE
36 /* Maximum number of opcode slots in a VLIW instruction. */
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. */
47 enum xtensa_relax_statesE
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. */
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. */
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
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
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. */
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. */
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. */
90 /* The next fragment would like its first instruction to NOT cross an
91 instruction fetch boundary. */
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
101 /* This will be turned into a NOP or NOP.N if the previous instruction
102 is expanded to negate a loop. */
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. */
110 /* Another fragment could generate an expansion here but has not yet. */
113 /* Expansion has been generated by an instruction that generates a
114 literal. However, the stretch has NOT been reported yet in this
118 /* Expansion has been generated by an instruction that generates a
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. */
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. */
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
140 /* The last instruction in this fragment (at->fr_opcode) contains a
141 literal. It has already been expanded at least 1 step. */
144 /* The last instruction in this fragment (at->fr_opcode) contains a
145 literal. It has already been expanded at least 2 steps. */
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
156 /* This marks the location of a pipeline stall. We can fill these guys
157 in for alignment of any size. */
160 /* This marks the location as unreachable. The assembler may widen or
161 narrow this area to meet alignment requirements of nearby
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. */
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. */
180 /* This is used as a stopper to bound the number of steps that
182 #define RELAX_IMMED_MAXSTEPS (RELAX_IMMED_STEP2 - RELAX_IMMED)
184 struct xtensa_frag_type
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.
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. */
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;
202 /* Inhibits relaxation of machine-dependent alignment frags the
203 first time through a relaxation.... */
204 unsigned int relax_seen
: 1;
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;
213 unsigned int is_specific_opcode
: 1; /* also implies no_transform */
215 unsigned int is_align
: 1;
216 unsigned int is_text_align
: 1;
217 unsigned int alignment
: 5;
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;
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;
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. */
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. */
241 /* Frag chain for LITERAL_POOL_BEGIN frags. */
242 struct frchain
*lit_frchain
;
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
;
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
];
256 /* The global aligner needs to walk backward through the list of
257 frags. This field is only valid after xtensa_end. */
262 /* For VLIW support, we need to know what slot a fixup applies to. */
263 typedef struct xtensa_fix_data_struct
266 symbolS
*X_add_symbol
;
267 offsetT X_add_number
;
271 /* Structure to record xtensa-specific symbol information. */
272 typedef struct xtensa_symfield_type
274 unsigned int is_loop_target
: 1;
275 unsigned int is_branch_target
: 1;
276 } xtensa_symfield_type
;
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
;
286 /* Property section types. */
294 typedef struct xtensa_segment_info_struct
296 fragS
*literal_pool_loc
;
297 xtensa_block_info
*blocks
[max_xt_sec
];
298 } xtensa_segment_info
;
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 *);
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
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. */
355 #define md_post_relax_hook \
359 xtensa_post_relax_hook (); \
360 bfd_map_over_sections (stdoutput, renumber_sections, &i); \
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. */
370 #define md_relax_frag(segment, fragP, stretch) \
371 xtensa_relax_frag (fragP, stretch, &stretched)
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
383 /* Use line number format that is amenable to linker relaxation. */
384 #define DWARF2_USE_FIXED_ADVANCE_PC (linkrelax != 0)
387 /* Resource reservation info functions. */
389 /* Returns the number of copies of a particular unit. */
390 typedef int (*unit_num_copies_func
) (void *, xtensa_funcUnit
);
392 /* Returns the number of units the opcode uses. */
393 typedef int (*opcode_num_units_func
) (void *, xtensa_opcode
);
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);
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);
403 /* The above typedefs parameterize the resource_table so that the
404 optional scheduler doesn't need its own resource reservation system.
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):
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
415 Of course the optional scheduler has its own reservation table
418 int opcode_funcUnit_use_unit (void *, xtensa_opcode
, int);
419 int opcode_funcUnit_use_stage (void *, xtensa_opcode
, int);
425 int allocated_cycles
;
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
;
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);
443 #endif /* TC_XTENSA */