1/* Communication between reload.c and reload1.c.
2   Copyright (C) 1987, 1991, 1992, 1993, 1994, 1995, 1997, 1998,
3   1999, 2000, 2001, 2003, 2004 Free Software Foundation, Inc.
4
5This file is part of GCC.
6
7GCC is free software; you can redistribute it and/or modify it under
8the terms of the GNU General Public License as published by the Free
9Software Foundation; either version 2, or (at your option) any later
10version.
11
12GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13WARRANTY; without even the implied warranty of MERCHANTABILITY or
14FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
15for more details.
16
17You should have received a copy of the GNU General Public License
18along with GCC; see the file COPYING.  If not, write to the Free
19Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
2002110-1301, USA.  */
21
22
23/* If secondary reloads are the same for inputs and outputs, define those
24   macros here.  */
25
26#ifdef SECONDARY_RELOAD_CLASS
27#define SECONDARY_INPUT_RELOAD_CLASS(CLASS, MODE, X) \
28  SECONDARY_RELOAD_CLASS (CLASS, MODE, X)
29#define SECONDARY_OUTPUT_RELOAD_CLASS(CLASS, MODE, X) \
30  SECONDARY_RELOAD_CLASS (CLASS, MODE, X)
31#endif
32
33/* If MEMORY_MOVE_COST isn't defined, give it a default here.  */
34#ifndef MEMORY_MOVE_COST
35#define MEMORY_MOVE_COST(MODE,CLASS,IN) \
36  (4 + memory_move_secondary_cost ((MODE), (CLASS), (IN)))
37#endif
38extern int memory_move_secondary_cost (enum machine_mode, enum reg_class, int);
39
40/* Maximum number of reloads we can need.  */
41#define MAX_RELOADS (2 * MAX_RECOG_OPERANDS * (MAX_REGS_PER_ADDRESS + 1))
42
43/* Encode the usage of a reload.  The following codes are supported:
44
45   RELOAD_FOR_INPUT		reload of an input operand
46   RELOAD_FOR_OUTPUT		likewise, for output
47   RELOAD_FOR_INSN		a reload that must not conflict with anything
48				used in the insn, but may conflict with
49				something used before or after the insn
50   RELOAD_FOR_INPUT_ADDRESS	reload for parts of the address of an object
51				that is an input reload
52   RELOAD_FOR_INPADDR_ADDRESS	reload needed for RELOAD_FOR_INPUT_ADDRESS
53   RELOAD_FOR_OUTPUT_ADDRESS	like RELOAD_FOR INPUT_ADDRESS, for output
54   RELOAD_FOR_OUTADDR_ADDRESS	reload needed for RELOAD_FOR_OUTPUT_ADDRESS
55   RELOAD_FOR_OPERAND_ADDRESS	reload for the address of a non-reloaded
56				operand; these don't conflict with
57				any other addresses.
58   RELOAD_FOR_OPADDR_ADDR	reload needed for RELOAD_FOR_OPERAND_ADDRESS
59                                reloads; usually secondary reloads
60   RELOAD_OTHER			none of the above, usually multiple uses
61   RELOAD_FOR_OTHER_ADDRESS     reload for part of the address of an input
62				that is marked RELOAD_OTHER.
63
64   This used to be "enum reload_when_needed" but some debuggers have trouble
65   with an enum tag and variable of the same name.  */
66
67enum reload_type
68{
69  RELOAD_FOR_INPUT, RELOAD_FOR_OUTPUT, RELOAD_FOR_INSN,
70  RELOAD_FOR_INPUT_ADDRESS, RELOAD_FOR_INPADDR_ADDRESS,
71  RELOAD_FOR_OUTPUT_ADDRESS, RELOAD_FOR_OUTADDR_ADDRESS,
72  RELOAD_FOR_OPERAND_ADDRESS, RELOAD_FOR_OPADDR_ADDR,
73  RELOAD_OTHER, RELOAD_FOR_OTHER_ADDRESS
74};
75
76#ifdef GCC_INSN_CODES_H
77/* Each reload is recorded with a structure like this.  */
78struct reload
79{
80  /* The value to reload from */
81  rtx in;
82  /* Where to store reload-reg afterward if nec (often the same as
83     reload_in)  */
84  rtx out;
85
86  /* The class of registers to reload into.  */
87  enum reg_class class;
88
89  /* The mode this operand should have when reloaded, on input.  */
90  enum machine_mode inmode;
91  /* The mode this operand should have when reloaded, on output.  */
92  enum machine_mode outmode;
93
94  /* The mode of the reload register.  */
95  enum machine_mode mode;
96
97  /* the largest number of registers this reload will require.  */
98  unsigned int nregs;
99
100  /* Positive amount to increment or decrement by if
101     reload_in is a PRE_DEC, PRE_INC, POST_DEC, POST_INC.
102     Ignored otherwise (don't assume it is zero).  */
103  int inc;
104  /* A reg for which reload_in is the equivalent.
105     If reload_in is a symbol_ref which came from
106     reg_equiv_constant, then this is the pseudo
107     which has that symbol_ref as equivalent.  */
108  rtx in_reg;
109  rtx out_reg;
110
111  /* Used in find_reload_regs to record the allocated register.  */
112  int regno;
113  /* This is the register to reload into.  If it is zero when `find_reloads'
114     returns, you must find a suitable register in the class specified by
115     reload_reg_class, and store here an rtx for that register with mode from
116     reload_inmode or reload_outmode.  */
117  rtx reg_rtx;
118  /* The operand number being reloaded.  This is used to group related reloads
119     and need not always be equal to the actual operand number in the insn,
120     though it current will be; for in-out operands, it is one of the two
121     operand numbers.  */
122  int opnum;
123
124  /* Gives the reload number of a secondary input reload, when needed;
125     otherwise -1.  */
126  int secondary_in_reload;
127  /* Gives the reload number of a secondary output reload, when needed;
128     otherwise -1.  */
129  int secondary_out_reload;
130  /* If a secondary input reload is required, gives the INSN_CODE that uses the
131     secondary reload as a scratch register, or CODE_FOR_nothing if the
132     secondary reload register is to be an intermediate register.  */
133  enum insn_code secondary_in_icode;
134  /* Likewise, for a secondary output reload.  */
135  enum insn_code secondary_out_icode;
136
137  /* Classifies reload as needed either for addressing an input reload,
138     addressing an output, for addressing a non-reloaded mem ref, or for
139     unspecified purposes (i.e., more than one of the above).  */
140  enum reload_type when_needed;
141
142  /* Nonzero for an optional reload.  Optional reloads are ignored unless the
143     value is already sitting in a register.  */
144  unsigned int optional:1;
145  /* nonzero if this reload shouldn't be combined with another reload.  */
146  unsigned int nocombine:1;
147  /* Nonzero if this is a secondary register for one or more reloads.  */
148  unsigned int secondary_p:1;
149  /* Nonzero if this reload must use a register not already allocated to a
150     group.  */
151  unsigned int nongroup:1;
152};
153
154extern struct reload rld[MAX_RELOADS];
155extern int n_reloads;
156#endif
157
158extern GTY (()) VEC(rtx,gc) *reg_equiv_memory_loc_vec;
159extern rtx *reg_equiv_constant;
160extern rtx *reg_equiv_invariant;
161extern rtx *reg_equiv_memory_loc;
162extern rtx *reg_equiv_address;
163extern rtx *reg_equiv_mem;
164extern rtx *reg_equiv_alt_mem_list;
165
166/* Element N is the list of insns that initialized reg N from its equivalent
167   constant or memory slot.  */
168extern GTY((length("reg_equiv_init_size"))) rtx *reg_equiv_init;
169
170/* The size of the previous array, for GC purposes.  */
171extern GTY(()) int reg_equiv_init_size;
172
173/* All the "earlyclobber" operands of the current insn
174   are recorded here.  */
175extern int n_earlyclobbers;
176extern rtx reload_earlyclobbers[MAX_RECOG_OPERANDS];
177
178/* Save the number of operands.  */
179extern int reload_n_operands;
180
181/* First uid used by insns created by reload in this function.
182   Used in find_equiv_reg.  */
183extern int reload_first_uid;
184
185/* Nonzero if indirect addressing is supported when the innermost MEM is
186   of the form (MEM (SYMBOL_REF sym)).  It is assumed that the level to
187   which these are valid is the same as spill_indirect_levels, above.  */
188
189extern char indirect_symref_ok;
190
191/* Nonzero if an address (plus (reg frame_pointer) (reg ...)) is valid.  */
192extern char double_reg_address_ok;
193
194extern int num_not_at_initial_offset;
195
196#if defined SET_HARD_REG_BIT && defined CLEAR_REG_SET
197/* This structure describes instructions which are relevant for reload.
198   Apart from all regular insns, this also includes CODE_LABELs, since they
199   must be examined for register elimination.  */
200struct insn_chain
201{
202  /* Links to the neighbor instructions.  */
203  struct insn_chain *next, *prev;
204
205  /* Link through a chains set up by calculate_needs_all_insns, containing
206     all insns that need reloading.  */
207  struct insn_chain *next_need_reload;
208
209  /* The basic block this insn is in.  */
210  int block;
211  /* The rtx of the insn.  */
212  rtx insn;
213  /* Register life information: record all live hard registers, and all
214     live pseudos that have a hard register.  */
215  regset_head live_throughout;
216  regset_head dead_or_set;
217
218  /* Copies of the global variables computed by find_reloads.  */
219  struct reload *rld;
220  int n_reloads;
221
222  /* Indicates which registers have already been used for spills.  */
223  HARD_REG_SET used_spill_regs;
224
225  /* Nonzero if find_reloads said the insn requires reloading.  */
226  unsigned int need_reload:1;
227  /* Nonzero if find_reloads needs to be run during reload_as_needed to
228     perform modifications on any operands.  */
229  unsigned int need_operand_change:1;
230  /* Nonzero if eliminate_regs_in_insn said it requires eliminations.  */
231  unsigned int need_elim:1;
232  /* Nonzero if this insn was inserted by perform_caller_saves.  */
233  unsigned int is_caller_save_insn:1;
234};
235
236/* A chain of insn_chain structures to describe all non-note insns in
237   a function.  */
238extern struct insn_chain *reload_insn_chain;
239
240/* Allocate a new insn_chain structure.  */
241extern struct insn_chain *new_insn_chain (void);
242
243extern void compute_use_by_pseudos (HARD_REG_SET *, regset);
244#endif
245
246/* Functions from reload.c:  */
247
248extern enum reg_class secondary_reload_class (bool, enum reg_class,
249					      enum machine_mode, rtx);
250
251#ifdef GCC_INSN_CODES_H
252extern enum reg_class scratch_reload_class (enum insn_code);
253#endif
254
255/* Return a memory location that will be used to copy X in mode MODE.
256   If we haven't already made a location for this mode in this insn,
257   call find_reloads_address on the location being returned.  */
258extern rtx get_secondary_mem (rtx, enum machine_mode, int, enum reload_type);
259
260/* Clear any secondary memory locations we've made.  */
261extern void clear_secondary_mem (void);
262
263/* Transfer all replacements that used to be in reload FROM to be in
264   reload TO.  */
265extern void transfer_replacements (int, int);
266
267/* IN_RTX is the value loaded by a reload that we now decided to inherit,
268   or a subpart of it.  If we have any replacements registered for IN_RTX,
269   cancel the reloads that were supposed to load them.
270   Return nonzero if we canceled any reloads.  */
271extern int remove_address_replacements (rtx in_rtx);
272
273/* Like rtx_equal_p except that it allows a REG and a SUBREG to match
274   if they are the same hard reg, and has special hacks for
275   autoincrement and autodecrement.  */
276extern int operands_match_p (rtx, rtx);
277
278/* Return 1 if altering OP will not modify the value of CLOBBER.  */
279extern int safe_from_earlyclobber (rtx, rtx);
280
281/* Search the body of INSN for values that need reloading and record them
282   with push_reload.  REPLACE nonzero means record also where the values occur
283   so that subst_reloads can be used.  */
284extern int find_reloads (rtx, int, int, int, short *);
285
286/* Compute the sum of X and Y, making canonicalizations assumed in an
287   address, namely: sum constant integers, surround the sum of two
288   constants with a CONST, put the constant as the second operand, and
289   group the constant on the outermost sum.  */
290extern rtx form_sum (rtx, rtx);
291
292/* Substitute into the current INSN the registers into which we have reloaded
293   the things that need reloading.  */
294extern void subst_reloads (rtx);
295
296/* Make a copy of any replacements being done into X and move those copies
297   to locations in Y, a copy of X.  We only look at the highest level of
298   the RTL.  */
299extern void copy_replacements (rtx, rtx);
300
301/* Change any replacements being done to *X to be done to *Y */
302extern void move_replacements (rtx *x, rtx *y);
303
304/* If LOC was scheduled to be replaced by something, return the replacement.
305   Otherwise, return *LOC.  */
306extern rtx find_replacement (rtx *);
307
308/* Nonzero if modifying X will affect IN.  */
309extern int reg_overlap_mentioned_for_reload_p (rtx, rtx);
310
311/* Check the insns before INSN to see if there is a suitable register
312   containing the same value as GOAL.  */
313extern rtx find_equiv_reg (rtx, rtx, enum reg_class, int, short *,
314			   int, enum machine_mode);
315
316/* Return 1 if register REGNO is the subject of a clobber in insn INSN.  */
317extern int regno_clobbered_p (unsigned int, rtx, enum machine_mode, int);
318
319/* Return 1 if X is an operand of an insn that is being earlyclobbered.  */
320extern int earlyclobber_operand_p (rtx);
321
322/* Record one reload that needs to be performed.  */
323extern int push_reload (rtx, rtx, rtx *, rtx *, enum reg_class,
324			enum machine_mode, enum machine_mode,
325			int, int, int, enum reload_type);
326
327/* Functions in postreload.c:  */
328extern void reload_cse_regs (rtx);
329
330/* Functions in reload1.c:  */
331
332/* Initialize the reload pass once per compilation.  */
333extern void init_reload (void);
334
335/* The reload pass itself.  */
336extern int reload (rtx, int);
337
338/* Mark the slots in regs_ever_live for the hard regs
339   used by pseudo-reg number REGNO.  */
340extern void mark_home_live (int);
341
342/* Scan X and replace any eliminable registers (such as fp) with a
343   replacement (such as sp), plus an offset.  */
344extern rtx eliminate_regs (rtx, enum machine_mode, rtx);
345
346/* Deallocate the reload register used by reload number R.  */
347extern void deallocate_reload_reg (int r);
348
349/* Functions in caller-save.c:  */
350
351/* Initialize for caller-save.  */
352extern void init_caller_save (void);
353
354/* Initialize save areas by showing that we haven't allocated any yet.  */
355extern void init_save_areas (void);
356
357/* Allocate save areas for any hard registers that might need saving.  */
358extern void setup_save_areas (void);
359
360/* Find the places where hard regs are live across calls and save them.  */
361extern void save_call_clobbered_regs (void);
362
363/* Replace (subreg (reg)) with the appropriate (reg) for any operands.  */
364extern void cleanup_subreg_operands (rtx);
365
366/* Debugging support.  */
367extern void debug_reload_to_stream (FILE *);
368extern void debug_reload (void);
369
370/* Compute the actual register we should reload to, in case we're
371   reloading to/from a register that is wider than a word.  */
372extern rtx reload_adjust_reg_for_mode (rtx, enum machine_mode);
373