]> Git Repo - binutils.git/blame - gas/config/tc-xtensa.h
2008-03-03 Sterling Augustine <[email protected]>
[binutils.git] / gas / config / tc-xtensa.h
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e0001a05 1/* tc-xtensa.h -- Header file for tc-xtensa.c.
58502fec 2 Copyright (C) 2003, 2004, 2005, 2007, 2008 Free Software Foundation, Inc.
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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
ec2655a6 8 the Free Software Foundation; either version 3, or (at your option)
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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
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18 Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
19 02110-1301, USA. */
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20
21#ifndef TC_XTENSA
22#define TC_XTENSA 1
23
e0001a05 24struct fix;
e0001a05 25
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26#ifndef OBJ_ELF
27#error Xtensa support requires ELF object format
28#endif
29
43cd72b9 30#include "xtensa-isa.h"
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31#include "xtensa-config.h"
32
33#define TARGET_BYTES_BIG_ENDIAN XCHAL_HAVE_BE
34
35
43cd72b9 36/* Maximum number of opcode slots in a VLIW instruction. */
b08b5071 37#define MAX_SLOTS 15
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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
47enum xtensa_relax_statesE
48{
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49 RELAX_XTENSA_NONE,
50
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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. */
110
111 RELAX_LITERAL,
112 /* Another fragment could generate an expansion here but has not yet. */
113
114 RELAX_LITERAL_NR,
115 /* Expansion has been generated by an instruction that generates a
116 literal. However, the stretch has NOT been reported yet in this
117 fragment. */
118
119 RELAX_LITERAL_FINAL,
120 /* Expansion has been generated by an instruction that generates a
121 literal. */
122
123 RELAX_LITERAL_POOL_BEGIN,
124 RELAX_LITERAL_POOL_END,
125 /* Technically these are not relaxations at all but mark a location
126 to store literals later. Note that fr_var stores the frchain for
127 BEGIN frags and fr_var stores now_seg for END frags. */
128
129 RELAX_NARROW,
130 /* The last instruction in this fragment (at->fr_opcode) can be
131 freely replaced with a single wider instruction if a future
132 alignment desires or needs it. */
133
134 RELAX_IMMED,
135 /* The last instruction in this fragment (at->fr_opcode) contains
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136 an immediate or symbol. If the value does not fit, relax the
137 opcode using expansions from the relax table. */
c138bc38 138
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139 RELAX_IMMED_STEP1,
140 /* The last instruction in this fragment (at->fr_opcode) contains a
b81bf389 141 literal. It has already been expanded 1 step. */
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142
143 RELAX_IMMED_STEP2,
144 /* The last instruction in this fragment (at->fr_opcode) contains a
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145 literal. It has already been expanded 2 steps. */
146
147 RELAX_IMMED_STEP3,
148 /* The last instruction in this fragment (at->fr_opcode) contains a
149 literal. It has already been expanded 3 steps. */
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150
151 RELAX_SLOTS,
152 /* There are instructions within the last VLIW instruction that need
153 relaxation. Find the relaxation based on the slot info in
154 xtensa_frag_type. Relaxations that deal with particular opcodes
155 are slot-based (e.g., converting a MOVI to an L32R). Relaxations
156 that deal with entire instructions, such as alignment, are not
157 slot-based. */
158
159 RELAX_FILL_NOP,
160 /* This marks the location of a pipeline stall. We can fill these guys
161 in for alignment of any size. */
162
163 RELAX_UNREACHABLE,
164 /* This marks the location as unreachable. The assembler may widen or
165 narrow this area to meet alignment requirements of nearby
166 instructions. */
167
168 RELAX_MAYBE_UNREACHABLE,
169 /* This marks the location as possibly unreachable. These are placed
170 after a branch that may be relaxed into a branch and jump. If the
c138bc38 171 branch is relaxed, then this frag will be converted to a
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172 RELAX_UNREACHABLE frag. */
173
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174 RELAX_ORG,
175 /* This marks the location as having previously been an rs_org frag.
176 rs_org frags are converted to fill-zero frags immediately after
177 relaxation. However, we need to remember where they were so we can
178 prevent the linker from changing the size of any frag between the
179 section start and the org frag. */
180
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181 RELAX_NONE
182};
183
184/* This is used as a stopper to bound the number of steps that
185 can be taken. */
b81bf389 186#define RELAX_IMMED_MAXSTEPS (RELAX_IMMED_STEP3 - RELAX_IMMED)
43cd72b9 187
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188struct xtensa_frag_type
189{
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190 /* Info about the current state of assembly, e.g., transform,
191 absolute_literals, etc. These need to be passed to the backend and
192 then to the object file.
193
194 When is_assembly_state_set is false, the frag inherits some of the
195 state settings from the previous frag in this segment. Because it
196 is not possible to intercept all fragment closures (frag_more and
197 frag_append_1_char can close a frag), we use a pass after initial
198 assembly to fill in the assembly states. */
199
200 unsigned int is_assembly_state_set : 1;
201 unsigned int is_no_density : 1;
202 unsigned int is_no_transform : 1;
7c834684 203 unsigned int use_longcalls : 1;
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204 unsigned int use_absolute_literals : 1;
205
206 /* Inhibits relaxation of machine-dependent alignment frags the
207 first time through a relaxation.... */
208 unsigned int relax_seen : 1;
209
0fa77c95 210 /* Information that is needed in the object file and set when known. */
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211 unsigned int is_literal : 1;
212 unsigned int is_loop_target : 1;
213 unsigned int is_branch_target : 1;
214 unsigned int is_insn : 1;
215 unsigned int is_unreachable : 1;
e0001a05 216
43cd72b9 217 unsigned int is_specific_opcode : 1; /* also implies no_transform */
e0001a05 218
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219 unsigned int is_align : 1;
220 unsigned int is_text_align : 1;
221 unsigned int alignment : 5;
222
223 /* A frag with this bit set is the first in a loop that actually
224 contains an instruction. */
225 unsigned int is_first_loop_insn : 1;
e0001a05 226
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227 /* A frag with this bit set is a branch that we are using to
228 align branch targets as if it were a normal narrow instruction. */
229 unsigned int is_aligning_branch : 1;
230
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231 /* For text fragments that can generate literals at relax time, this
232 variable points to the frag where the literal will be stored. For
233 literal frags, this variable points to the nearest literal pool
234 location frag. This literal frag will be moved to after this
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235 location. For RELAX_LITERAL_POOL_BEGIN frags, this field points
236 to the frag immediately before the corresponding RELAX_LITERAL_POOL_END
237 frag, to make moving frags for this literal pool efficient. */
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238 fragS *literal_frag;
239
240 /* The destination segment for literal frags. (Note that this is only
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241 valid after xtensa_move_literals.) This field is also used for
242 LITERAL_POOL_END frags. */
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243 segT lit_seg;
244
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245 /* Frag chain for LITERAL_POOL_BEGIN frags. */
246 struct frchain *lit_frchain;
247
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248 /* For the relaxation scheme, some literal fragments can have their
249 expansions modified by an instruction that relaxes. */
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250 int text_expansion[MAX_SLOTS];
251 int literal_expansion[MAX_SLOTS];
252 int unreported_expansion;
253
254 /* For text fragments that can generate literals at relax time: */
255 fragS *literal_frags[MAX_SLOTS];
256 enum xtensa_relax_statesE slot_subtypes[MAX_SLOTS];
257 symbolS *slot_symbols[MAX_SLOTS];
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258 offsetT slot_offsets[MAX_SLOTS];
259
260 /* The global aligner needs to walk backward through the list of
261 frags. This field is only valid after xtensa_end. */
262 fragS *fr_prev;
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263};
264
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265
266/* For VLIW support, we need to know what slot a fixup applies to. */
267typedef struct xtensa_fix_data_struct
268{
269 int slot;
270 symbolS *X_add_symbol;
271 offsetT X_add_number;
272} xtensa_fix_data;
273
274
275/* Structure to record xtensa-specific symbol information. */
276typedef struct xtensa_symfield_type
e0001a05 277{
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278 unsigned int is_loop_target : 1;
279 unsigned int is_branch_target : 1;
6a7eedfe 280 symbolS *next_expr_symbol;
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281} xtensa_symfield_type;
282
283
284/* Structure for saving information about a block of property data
285 for frags that have the same flags. The forward reference is
286 in this header file. The actual definition is in tc-xtensa.c. */
287struct xtensa_block_info_struct;
288typedef struct xtensa_block_info_struct xtensa_block_info;
289
e0001a05 290
43cd72b9 291/* Property section types. */
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292typedef enum
293{
e0001a05 294 xt_literal_sec,
43cd72b9 295 xt_prop_sec,
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296 max_xt_sec
297} xt_section_type;
298
299typedef struct xtensa_segment_info_struct
300{
301 fragS *literal_pool_loc;
302 xtensa_block_info *blocks[max_xt_sec];
303} xtensa_segment_info;
304
e0001a05 305
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306extern const char *xtensa_target_format (void);
307extern void xtensa_init_fix_data (struct fix *);
308extern void xtensa_frag_init (fragS *);
309extern int xtensa_force_relocation (struct fix *);
30f725a1 310extern int xtensa_validate_fix_sub (struct fix *);
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311extern void xtensa_frob_label (struct symbol *);
312extern void xtensa_end (void);
313extern void xtensa_post_relax_hook (void);
314extern void xtensa_file_arch_init (bfd *);
315extern void xtensa_flush_pending_output (void);
316extern bfd_boolean xtensa_fix_adjustable (struct fix *);
317extern void xtensa_symbol_new_hook (symbolS *);
318extern long xtensa_relax_frag (fragS *, long, int *);
319extern void xtensa_elf_section_change_hook (void);
320extern int xtensa_unrecognized_line (int);
321extern bfd_boolean xtensa_check_inside_bundle (void);
322extern void xtensa_handle_align (fragS *);
9456465c 323extern char *xtensa_section_rename (char *);
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324
325#define TARGET_FORMAT xtensa_target_format ()
326#define TARGET_ARCH bfd_arch_xtensa
327#define TC_SEGMENT_INFO_TYPE xtensa_segment_info
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328#define TC_SYMFIELD_TYPE struct xtensa_symfield_type
329#define TC_FIX_TYPE xtensa_fix_data
330#define TC_INIT_FIX_DATA(x) xtensa_init_fix_data (x)
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331#define TC_FRAG_TYPE struct xtensa_frag_type
332#define TC_FRAG_INIT(frag) xtensa_frag_init (frag)
43cd72b9 333#define TC_FORCE_RELOCATION(fix) xtensa_force_relocation (fix)
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334#define TC_FORCE_RELOCATION_SUB_SAME(fix, seg) \
335 (! SEG_NORMAL (seg) || xtensa_force_relocation (fix))
336#define TC_VALIDATE_FIX_SUB(fix) xtensa_validate_fix_sub (fix)
43cd72b9 337#define NO_PSEUDO_DOT xtensa_check_inside_bundle ()
e0001a05 338#define tc_canonicalize_symbol_name(s) xtensa_section_rename (s)
9456465c 339#define tc_canonicalize_section_name(s) xtensa_section_rename (s)
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340#define tc_init_after_args() xtensa_file_arch_init (stdoutput)
341#define tc_fix_adjustable(fix) xtensa_fix_adjustable (fix)
342#define tc_frob_label(sym) xtensa_frob_label (sym)
43cd72b9 343#define tc_unrecognized_line(ch) xtensa_unrecognized_line (ch)
6a7eedfe 344#define tc_symbol_new_hook(sym) xtensa_symbol_new_hook (sym)
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345#define md_do_align(a,b,c,d,e) xtensa_flush_pending_output ()
346#define md_elf_section_change_hook xtensa_elf_section_change_hook
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347#define md_end xtensa_end
348#define md_flush_pending_output() xtensa_flush_pending_output ()
349#define md_operand(x)
350#define TEXT_SECTION_NAME xtensa_section_rename (".text")
351#define DATA_SECTION_NAME xtensa_section_rename (".data")
352#define BSS_SECTION_NAME xtensa_section_rename (".bss")
43cd72b9 353#define HANDLE_ALIGN(fragP) xtensa_handle_align (fragP)
cf523b8e 354#define MAX_MEM_FOR_RS_ALIGN_CODE 1
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355
356
357/* The renumber_section function must be mapped over all the sections
358 after calling xtensa_post_relax_hook. That function is static in
359 write.c so it cannot be called from xtensa_post_relax_hook itself. */
360
361#define md_post_relax_hook \
362 do \
363 { \
364 int i = 0; \
365 xtensa_post_relax_hook (); \
366 bfd_map_over_sections (stdoutput, renumber_sections, &i); \
367 } \
368 while (0)
369
370
371/* Because xtensa relaxation can insert a new literal into the middle of
372 fragment and thus require re-running the relaxation pass on the
373 section, we need an explicit flag here. We explicitly use the name
374 "stretched" here to avoid changing the source code in write.c. */
375
376#define md_relax_frag(segment, fragP, stretch) \
377 xtensa_relax_frag (fragP, stretch, &stretched)
378
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379/* Only allow call frame debug info optimization when linker relaxation is
380 not enabled as otherwise we could generate the DWARF directives without
381 the relocs necessary to patch them up. */
382#define md_allow_eh_opt (linkrelax == 0)
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383
384#define LOCAL_LABELS_FB 1
385#define WORKING_DOT_WORD 1
386#define DOUBLESLASH_LINE_COMMENTS
387#define TC_HANDLES_FX_DONE
388#define TC_FINALIZE_SYMS_BEFORE_SIZE_SEG 0
43cd72b9 389#define TC_LINKRELAX_FIXUP(SEG) 0
e0001a05 390#define MD_APPLY_SYM_VALUE(FIX) 0
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391#define SUB_SEGMENT_ALIGN(SEG, FRCHAIN) 0
392
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393/* Use line number format that is amenable to linker relaxation. */
394#define DWARF2_USE_FIXED_ADVANCE_PC (linkrelax != 0)
395
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396
397/* Resource reservation info functions. */
398
399/* Returns the number of copies of a particular unit. */
400typedef int (*unit_num_copies_func) (void *, xtensa_funcUnit);
401
402/* Returns the number of units the opcode uses. */
403typedef int (*opcode_num_units_func) (void *, xtensa_opcode);
404
c138bc38 405/* Given an opcode and an index into the opcode's funcUnit list,
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406 returns the unit used for the index. */
407typedef int (*opcode_funcUnit_use_unit_func) (void *, xtensa_opcode, int);
408
c138bc38 409/* Given an opcode and an index into the opcode's funcUnit list,
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410 returns the cycle during which the unit is used. */
411typedef int (*opcode_funcUnit_use_stage_func) (void *, xtensa_opcode, int);
412
c138bc38 413/* The above typedefs parameterize the resource_table so that the
43cd72b9 414 optional scheduler doesn't need its own resource reservation system.
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415
416 For simple resource checking, which is all that happens normally,
417 the functions will be as follows (with some wrapping to make the
418 interface more convenient):
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419
420 unit_num_copies_func = xtensa_funcUnit_num_copies
421 opcode_num_units_func = xtensa_opcode_num_funcUnit_uses
422 opcode_funcUnit_use_unit_func = xtensa_opcode_funcUnit_use->unit
423 opcode_funcUnit_use_stage_func = xtensa_opcode_funcUnit_use->stage
424
c138bc38 425 Of course the optional scheduler has its own reservation table
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426 and functions. */
427
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428int opcode_funcUnit_use_unit (void *, xtensa_opcode, int);
429int opcode_funcUnit_use_stage (void *, xtensa_opcode, int);
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430
431typedef struct
432{
433 void *data;
434 int cycles;
435 int allocated_cycles;
436 int num_units;
437 unit_num_copies_func unit_num_copies;
438 opcode_num_units_func opcode_num_units;
439 opcode_funcUnit_use_unit_func opcode_unit_use;
440 opcode_funcUnit_use_stage_func opcode_unit_stage;
0bf60745 441 unsigned char **units;
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442} resource_table;
443
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444resource_table *new_resource_table
445 (void *, int, int, unit_num_copies_func, opcode_num_units_func,
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446 opcode_funcUnit_use_unit_func, opcode_funcUnit_use_stage_func);
447void resize_resource_table (resource_table *, int);
448void clear_resource_table (resource_table *);
449bfd_boolean resources_available (resource_table *, xtensa_opcode, int);
450void reserve_resources (resource_table *, xtensa_opcode, int);
451void release_resources (resource_table *, xtensa_opcode, int);
e0001a05 452
e0001a05 453#endif /* TC_XTENSA */
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