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-rw-r--r--src/freedreno/ir3/ir3_legalize.c496
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diff --git a/src/freedreno/ir3/ir3_legalize.c b/src/freedreno/ir3/ir3_legalize.c
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+/*
+ * Copyright (C) 2014 Rob Clark <[email protected]>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ * Authors:
+ * Rob Clark <[email protected]>
+ */
+
+#include "util/ralloc.h"
+#include "util/u_math.h"
+
+#include "ir3.h"
+
+/*
+ * Legalize:
+ *
+ * We currently require that scheduling ensures that we have enough nop's
+ * in all the right places. The legalize step mostly handles fixing up
+ * instruction flags ((ss)/(sy)/(ei)), and collapses sequences of nop's
+ * into fewer nop's w/ rpt flag.
+ */
+
+struct ir3_legalize_ctx {
+ int num_samp;
+ bool has_ssbo;
+ int max_bary;
+};
+
+struct ir3_legalize_state {
+ regmask_t needs_ss;
+ regmask_t needs_ss_war; /* write after read */
+ regmask_t needs_sy;
+};
+
+struct ir3_legalize_block_data {
+ bool valid;
+ struct ir3_legalize_state state;
+};
+
+/* We want to evaluate each block from the position of any other
+ * predecessor block, in order that the flags set are the union of
+ * all possible program paths.
+ *
+ * To do this, we need to know the output state (needs_ss/ss_war/sy)
+ * of all predecessor blocks. The tricky thing is loops, which mean
+ * that we can't simply recursively process each predecessor block
+ * before legalizing the current block.
+ *
+ * How we handle that is by looping over all the blocks until the
+ * results converge. If the output state of a given block changes
+ * in a given pass, this means that all successor blocks are not
+ * yet fully legalized.
+ */
+
+static bool
+legalize_block(struct ir3_legalize_ctx *ctx, struct ir3_block *block)
+{
+ struct ir3_legalize_block_data *bd = block->data;
+
+ if (bd->valid)
+ return false;
+
+ struct ir3_instruction *last_input = NULL;
+ struct ir3_instruction *last_rel = NULL;
+ struct ir3_instruction *last_n = NULL;
+ struct list_head instr_list;
+ struct ir3_legalize_state prev_state = bd->state;
+ struct ir3_legalize_state *state = &bd->state;
+
+ /* our input state is the OR of all predecessor blocks' state: */
+ for (unsigned i = 0; i < block->predecessors_count; i++) {
+ struct ir3_legalize_block_data *pbd = block->predecessors[i]->data;
+ struct ir3_legalize_state *pstate = &pbd->state;
+
+ /* Our input (ss)/(sy) state is based on OR'ing the output
+ * state of all our predecessor blocks
+ */
+ regmask_or(&state->needs_ss,
+ &state->needs_ss, &pstate->needs_ss);
+ regmask_or(&state->needs_ss_war,
+ &state->needs_ss_war, &pstate->needs_ss_war);
+ regmask_or(&state->needs_sy,
+ &state->needs_sy, &pstate->needs_sy);
+ }
+
+ /* remove all the instructions from the list, we'll be adding
+ * them back in as we go
+ */
+ list_replace(&block->instr_list, &instr_list);
+ list_inithead(&block->instr_list);
+
+ list_for_each_entry_safe (struct ir3_instruction, n, &instr_list, node) {
+ struct ir3_register *reg;
+ unsigned i;
+
+ n->flags &= ~(IR3_INSTR_SS | IR3_INSTR_SY);
+
+ if (is_meta(n))
+ continue;
+
+ if (is_input(n)) {
+ struct ir3_register *inloc = n->regs[1];
+ assert(inloc->flags & IR3_REG_IMMED);
+ ctx->max_bary = MAX2(ctx->max_bary, inloc->iim_val);
+ }
+
+ if (last_n && is_barrier(last_n))
+ n->flags |= IR3_INSTR_SS | IR3_INSTR_SY;
+
+ /* NOTE: consider dst register too.. it could happen that
+ * texture sample instruction (for example) writes some
+ * components which are unused. A subsequent instruction
+ * that writes the same register can race w/ the sam instr
+ * resulting in undefined results:
+ */
+ for (i = 0; i < n->regs_count; i++) {
+ reg = n->regs[i];
+
+ if (reg_gpr(reg)) {
+
+ /* TODO: we probably only need (ss) for alu
+ * instr consuming sfu result.. need to make
+ * some tests for both this and (sy)..
+ */
+ if (regmask_get(&state->needs_ss, reg)) {
+ n->flags |= IR3_INSTR_SS;
+ regmask_init(&state->needs_ss_war);
+ regmask_init(&state->needs_ss);
+ }
+
+ if (regmask_get(&state->needs_sy, reg)) {
+ n->flags |= IR3_INSTR_SY;
+ regmask_init(&state->needs_sy);
+ }
+ }
+
+ /* TODO: is it valid to have address reg loaded from a
+ * relative src (ie. mova a0, c<a0.x+4>)? If so, the
+ * last_rel check below should be moved ahead of this:
+ */
+ if (reg->flags & IR3_REG_RELATIV)
+ last_rel = n;
+ }
+
+ if (n->regs_count > 0) {
+ reg = n->regs[0];
+ if (regmask_get(&state->needs_ss_war, reg)) {
+ n->flags |= IR3_INSTR_SS;
+ regmask_init(&state->needs_ss_war);
+ regmask_init(&state->needs_ss);
+ }
+
+ if (last_rel && (reg->num == regid(REG_A0, 0))) {
+ last_rel->flags |= IR3_INSTR_UL;
+ last_rel = NULL;
+ }
+ }
+
+ /* cat5+ does not have an (ss) bit, if needed we need to
+ * insert a nop to carry the sync flag. Would be kinda
+ * clever if we were aware of this during scheduling, but
+ * this should be a pretty rare case:
+ */
+ if ((n->flags & IR3_INSTR_SS) && (opc_cat(n->opc) >= 5)) {
+ struct ir3_instruction *nop;
+ nop = ir3_NOP(block);
+ nop->flags |= IR3_INSTR_SS;
+ n->flags &= ~IR3_INSTR_SS;
+ }
+
+ /* need to be able to set (ss) on first instruction: */
+ if (list_empty(&block->instr_list) && (opc_cat(n->opc) >= 5))
+ ir3_NOP(block);
+
+ if (is_nop(n) && !list_empty(&block->instr_list)) {
+ struct ir3_instruction *last = list_last_entry(&block->instr_list,
+ struct ir3_instruction, node);
+ if (is_nop(last) && (last->repeat < 5)) {
+ last->repeat++;
+ last->flags |= n->flags;
+ continue;
+ }
+ }
+
+ list_addtail(&n->node, &block->instr_list);
+
+ if (is_sfu(n))
+ regmask_set(&state->needs_ss, n->regs[0]);
+
+ if (is_tex(n)) {
+ /* this ends up being the # of samp instructions.. but that
+ * is ok, everything else only cares whether it is zero or
+ * not. We do this here, rather than when we encounter a
+ * SAMP decl, because (especially in binning pass shader)
+ * the samp instruction(s) could get eliminated if the
+ * result is not used.
+ */
+ ctx->num_samp = MAX2(ctx->num_samp, n->cat5.samp + 1);
+ regmask_set(&state->needs_sy, n->regs[0]);
+ } else if (n->opc == OPC_RESINFO) {
+ regmask_set(&state->needs_ss, n->regs[0]);
+ ir3_NOP(block)->flags |= IR3_INSTR_SS;
+ } else if (is_load(n)) {
+ /* seems like ldlv needs (ss) bit instead?? which is odd but
+ * makes a bunch of flat-varying tests start working on a4xx.
+ */
+ if ((n->opc == OPC_LDLV) || (n->opc == OPC_LDL))
+ regmask_set(&state->needs_ss, n->regs[0]);
+ else
+ regmask_set(&state->needs_sy, n->regs[0]);
+ } else if (is_atomic(n->opc)) {
+ if (n->flags & IR3_INSTR_G)
+ regmask_set(&state->needs_sy, n->regs[0]);
+ else
+ regmask_set(&state->needs_ss, n->regs[0]);
+ }
+
+ if (is_ssbo(n->opc) || (is_atomic(n->opc) && (n->flags & IR3_INSTR_G)))
+ ctx->has_ssbo = true;
+
+ /* both tex/sfu appear to not always immediately consume
+ * their src register(s):
+ */
+ if (is_tex(n) || is_sfu(n) || is_mem(n)) {
+ foreach_src(reg, n) {
+ if (reg_gpr(reg))
+ regmask_set(&state->needs_ss_war, reg);
+ }
+ }
+
+ if (is_input(n))
+ last_input = n;
+
+ last_n = n;
+ }
+
+ if (last_input) {
+ /* special hack.. if using ldlv to bypass interpolation,
+ * we need to insert a dummy bary.f on which we can set
+ * the (ei) flag:
+ */
+ if (is_mem(last_input) && (last_input->opc == OPC_LDLV)) {
+ struct ir3_instruction *baryf;
+
+ /* (ss)bary.f (ei)r63.x, 0, r0.x */
+ baryf = ir3_instr_create(block, OPC_BARY_F);
+ baryf->flags |= IR3_INSTR_SS;
+ ir3_reg_create(baryf, regid(63, 0), 0);
+ ir3_reg_create(baryf, 0, IR3_REG_IMMED)->iim_val = 0;
+ ir3_reg_create(baryf, regid(0, 0), 0);
+
+ /* insert the dummy bary.f after last_input: */
+ list_delinit(&baryf->node);
+ list_add(&baryf->node, &last_input->node);
+
+ last_input = baryf;
+ }
+ last_input->regs[0]->flags |= IR3_REG_EI;
+ }
+
+ if (last_rel)
+ last_rel->flags |= IR3_INSTR_UL;
+
+ bd->valid = true;
+
+ if (memcmp(&prev_state, state, sizeof(*state))) {
+ /* our output state changed, this invalidates all of our
+ * successors:
+ */
+ for (unsigned i = 0; i < ARRAY_SIZE(block->successors); i++) {
+ if (!block->successors[i])
+ break;
+ struct ir3_legalize_block_data *pbd = block->successors[i]->data;
+ pbd->valid = false;
+ }
+ }
+
+ return true;
+}
+
+/* NOTE: branch instructions are always the last instruction(s)
+ * in the block. We take advantage of this as we resolve the
+ * branches, since "if (foo) break;" constructs turn into
+ * something like:
+ *
+ * block3 {
+ * ...
+ * 0029:021: mov.s32s32 r62.x, r1.y
+ * 0082:022: br !p0.x, target=block5
+ * 0083:023: br p0.x, target=block4
+ * // succs: if _[0029:021: mov.s32s32] block4; else block5;
+ * }
+ * block4 {
+ * 0084:024: jump, target=block6
+ * // succs: block6;
+ * }
+ * block5 {
+ * 0085:025: jump, target=block7
+ * // succs: block7;
+ * }
+ *
+ * ie. only instruction in block4/block5 is a jump, so when
+ * resolving branches we can easily detect this by checking
+ * that the first instruction in the target block is itself
+ * a jump, and setup the br directly to the jump's target
+ * (and strip back out the now unreached jump)
+ *
+ * TODO sometimes we end up with things like:
+ *
+ * br !p0.x, #2
+ * br p0.x, #12
+ * add.u r0.y, r0.y, 1
+ *
+ * If we swapped the order of the branches, we could drop one.
+ */
+static struct ir3_block *
+resolve_dest_block(struct ir3_block *block)
+{
+ /* special case for last block: */
+ if (!block->successors[0])
+ return block;
+
+ /* NOTE that we may or may not have inserted the jump
+ * in the target block yet, so conditions to resolve
+ * the dest to the dest block's successor are:
+ *
+ * (1) successor[1] == NULL &&
+ * (2) (block-is-empty || only-instr-is-jump)
+ */
+ if (block->successors[1] == NULL) {
+ if (list_empty(&block->instr_list)) {
+ return block->successors[0];
+ } else if (list_length(&block->instr_list) == 1) {
+ struct ir3_instruction *instr = list_first_entry(
+ &block->instr_list, struct ir3_instruction, node);
+ if (instr->opc == OPC_JUMP)
+ return block->successors[0];
+ }
+ }
+ return block;
+}
+
+static bool
+resolve_jump(struct ir3_instruction *instr)
+{
+ struct ir3_block *tblock =
+ resolve_dest_block(instr->cat0.target);
+ struct ir3_instruction *target;
+
+ if (tblock != instr->cat0.target) {
+ list_delinit(&instr->cat0.target->node);
+ instr->cat0.target = tblock;
+ return true;
+ }
+
+ target = list_first_entry(&tblock->instr_list,
+ struct ir3_instruction, node);
+
+ /* TODO maybe a less fragile way to do this. But we are expecting
+ * a pattern from sched_block() that looks like:
+ *
+ * br !p0.x, #else-block
+ * br p0.x, #if-block
+ *
+ * if the first branch target is +2, or if 2nd branch target is +1
+ * then we can just drop the jump.
+ */
+ unsigned next_block;
+ if (instr->cat0.inv == true)
+ next_block = 2;
+ else
+ next_block = 1;
+
+ if ((!target) || (target->ip == (instr->ip + next_block))) {
+ list_delinit(&instr->node);
+ return true;
+ } else {
+ instr->cat0.immed =
+ (int)target->ip - (int)instr->ip;
+ }
+ return false;
+}
+
+/* resolve jumps, removing jumps/branches to immediately following
+ * instruction which we end up with from earlier stages. Since
+ * removing an instruction can invalidate earlier instruction's
+ * branch offsets, we need to do this iteratively until no more
+ * branches are removed.
+ */
+static bool
+resolve_jumps(struct ir3 *ir)
+{
+ list_for_each_entry (struct ir3_block, block, &ir->block_list, node)
+ list_for_each_entry (struct ir3_instruction, instr, &block->instr_list, node)
+ if (is_flow(instr) && instr->cat0.target)
+ if (resolve_jump(instr))
+ return true;
+
+ return false;
+}
+
+/* we want to mark points where divergent flow control re-converges
+ * with (jp) flags. For now, since we don't do any optimization for
+ * things that start out as a 'do {} while()', re-convergence points
+ * will always be a branch or jump target. Note that this is overly
+ * conservative, since unconditional jump targets are not convergence
+ * points, we are just assuming that the other path to reach the jump
+ * target was divergent. If we were clever enough to optimize the
+ * jump at end of a loop back to a conditional branch into a single
+ * conditional branch, ie. like:
+ *
+ * add.f r1.w, r0.x, (neg)(r)c2.x <= loop start
+ * mul.f r1.z, r1.z, r0.x
+ * mul.f r1.y, r1.y, r0.x
+ * mul.f r0.z, r1.x, r0.x
+ * mul.f r0.w, r0.y, r0.x
+ * cmps.f.ge r0.x, (r)c2.y, (r)r1.w
+ * add.s r0.x, (r)r0.x, (r)-1
+ * sel.f32 r0.x, (r)c3.y, (r)r0.x, c3.x
+ * cmps.f.eq p0.x, r0.x, c3.y
+ * mov.f32f32 r0.x, r1.w
+ * mov.f32f32 r0.y, r0.w
+ * mov.f32f32 r1.x, r0.z
+ * (rpt2)nop
+ * br !p0.x, #-13
+ * (jp)mul.f r0.x, c263.y, r1.y
+ *
+ * Then we'd have to be more clever, as the convergence point is no
+ * longer a branch or jump target.
+ */
+static void
+mark_convergence_points(struct ir3 *ir)
+{
+ list_for_each_entry (struct ir3_block, block, &ir->block_list, node) {
+ list_for_each_entry (struct ir3_instruction, instr, &block->instr_list, node) {
+ if (is_flow(instr) && instr->cat0.target) {
+ struct ir3_instruction *target =
+ list_first_entry(&instr->cat0.target->instr_list,
+ struct ir3_instruction, node);
+ target->flags |= IR3_INSTR_JP;
+ }
+ }
+ }
+}
+
+void
+ir3_legalize(struct ir3 *ir, int *num_samp, bool *has_ssbo, int *max_bary)
+{
+ struct ir3_legalize_ctx *ctx = rzalloc(ir, struct ir3_legalize_ctx);
+ bool progress;
+
+ ctx->max_bary = -1;
+
+ /* allocate per-block data: */
+ list_for_each_entry (struct ir3_block, block, &ir->block_list, node) {
+ block->data = rzalloc(ctx, struct ir3_legalize_block_data);
+ }
+
+ /* process each block: */
+ do {
+ progress = false;
+ list_for_each_entry (struct ir3_block, block, &ir->block_list, node) {
+ progress |= legalize_block(ctx, block);
+ }
+ } while (progress);
+
+ *num_samp = ctx->num_samp;
+ *has_ssbo = ctx->has_ssbo;
+ *max_bary = ctx->max_bary;
+
+ do {
+ ir3_count_instructions(ir);
+ } while(resolve_jumps(ir));
+
+ mark_convergence_points(ir);
+
+ ralloc_free(ctx);
+}
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