Home | History | Annotate | Download | only in compiler 
      1 /*
      2  * Copyright (C) 2010 Marek Olk <maraeo (at) gmail.com>
      3  *
      4  * All Rights Reserved.
      5  *
      6  * Permission is hereby granted, free of charge, to any person obtaining
      7  * a copy of this software and associated documentation files (the
      8  * "Software"), to deal in the Software without restriction, including
      9  * without limitation the rights to use, copy, modify, merge, publish,
     10  * distribute, sublicense, and/or sell copies of the Software, and to
     11  * permit persons to whom the Software is furnished to do so, subject to
     12  * the following conditions:
     13  *
     14  * The above copyright notice and this permission notice (including the
     15  * next paragraph) shall be included in all copies or substantial
     16  * portions of the Software.
     17  *
     18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
     19  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
     20  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
     21  * IN NO EVENT SHALL THE COPYRIGHT OWNER(S) AND/OR ITS SUPPLIERS BE
     22  * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
     23  * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
     24  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
     25  *
     26  */
     27 
     28 #include "radeon_remove_constants.h"
     29 #include "radeon_dataflow.h"
     30 
     31 struct mark_used_data {
     32 	unsigned char * const_used;
     33 	unsigned * has_rel_addr;
     34 };
     35 
     36 static void remap_regs(void * userdata, struct rc_instruction * inst,
     37 			rc_register_file * pfile, unsigned int * pindex)
     38 {
     39 	unsigned *inv_remap_table = userdata;
     40 
     41 	if (*pfile == RC_FILE_CONSTANT) {
     42 		*pindex = inv_remap_table[*pindex];
     43 	}
     44 }
     45 
     46 static void mark_used(void * userdata, struct rc_instruction * inst,
     47 						struct rc_src_register * src)
     48 {
     49 	struct mark_used_data * d = userdata;
     50 
     51 	if (src->File == RC_FILE_CONSTANT) {
     52 		if (src->RelAddr) {
     53 			*d->has_rel_addr = 1;
     54 		} else {
     55 			d->const_used[src->Index] = 1;
     56 		}
     57 	}
     58 }
     59 
     60 void rc_remove_unused_constants(struct radeon_compiler *c, void *user)
     61 {
     62 	unsigned **out_remap_table = (unsigned**)user;
     63 	unsigned char *const_used;
     64 	unsigned *remap_table;
     65 	unsigned *inv_remap_table;
     66 	unsigned has_rel_addr = 0;
     67 	unsigned is_identity = 1;
     68 	unsigned are_externals_remapped = 0;
     69 	struct rc_constant *constants = c->Program.Constants.Constants;
     70 	struct mark_used_data d;
     71 	unsigned new_count;
     72 
     73 	if (!c->Program.Constants.Count) {
     74 		*out_remap_table = NULL;
     75 		return;
     76 	}
     77 
     78 	const_used = malloc(c->Program.Constants.Count);
     79 	memset(const_used, 0, c->Program.Constants.Count);
     80 
     81 	d.const_used = const_used;
     82 	d.has_rel_addr = &has_rel_addr;
     83 
     84 	/* Pass 1: Mark used constants. */
     85 	for (struct rc_instruction *inst = c->Program.Instructions.Next;
     86 	     inst != &c->Program.Instructions; inst = inst->Next) {
     87 		rc_for_all_reads_src(inst, mark_used, &d);
     88 	}
     89 
     90 	/* Pass 2: If there is relative addressing or dead constant elimination
     91 	 * is disabled, mark all externals as used. */
     92 	if (has_rel_addr || !c->remove_unused_constants) {
     93 		for (unsigned i = 0; i < c->Program.Constants.Count; i++)
     94 			if (constants[i].Type == RC_CONSTANT_EXTERNAL)
     95 				const_used[i] = 1;
     96 	}
     97 
     98 	/* Pass 3: Make the remapping table and remap constants.
     99 	 * This pass removes unused constants simply by overwriting them by other constants. */
    100 	remap_table = malloc(c->Program.Constants.Count * sizeof(unsigned));
    101 	inv_remap_table = malloc(c->Program.Constants.Count * sizeof(unsigned));
    102 	new_count = 0;
    103 
    104 	for (unsigned i = 0; i < c->Program.Constants.Count; i++) {
    105 		if (const_used[i]) {
    106 			remap_table[new_count] = i;
    107 			inv_remap_table[i] = new_count;
    108 
    109 			if (i != new_count) {
    110 				if (constants[i].Type == RC_CONSTANT_EXTERNAL)
    111 					are_externals_remapped = 1;
    112 
    113 				constants[new_count] = constants[i];
    114 				is_identity = 0;
    115 			}
    116 			new_count++;
    117 		}
    118 	}
    119 
    120 	/*  is_identity ==> new_count == old_count
    121 	 * !is_identity ==> new_count <  old_count */
    122 	assert( is_identity || new_count <  c->Program.Constants.Count);
    123 	assert(!((has_rel_addr || !c->remove_unused_constants) && are_externals_remapped));
    124 
    125 	/* Pass 4: Redirect reads of all constants to their new locations. */
    126 	if (!is_identity) {
    127 		for (struct rc_instruction *inst = c->Program.Instructions.Next;
    128 		     inst != &c->Program.Instructions; inst = inst->Next) {
    129 			rc_remap_registers(inst, remap_regs, inv_remap_table);
    130 		}
    131 	}
    132 
    133 	/* Set the new constant count. Note that new_count may be less than
    134 	 * Count even though the remapping function is identity. In that case,
    135 	 * the constants have been removed at the end of the array. */
    136 	c->Program.Constants.Count = new_count;
    137 
    138 	if (are_externals_remapped) {
    139 		*out_remap_table = remap_table;
    140 	} else {
    141 		*out_remap_table = NULL;
    142 		free(remap_table);
    143 	}
    144 
    145 	free(const_used);
    146 	free(inv_remap_table);
    147 
    148 	if (c->Debug & RC_DBG_LOG)
    149 		rc_constants_print(&c->Program.Constants);
    150 }
    151