path: root/src/panfrost/bifrost/compiler.h

/*
 * Copyright (C) 2020 Collabora Ltd.
 *
 * 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 (Collabora):
 *      Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
 */

#ifndef __BIFROST_COMPILER_H
#define __BIFROST_COMPILER_H

#include "bifrost.h"
#include "bi_opcodes.h"
#include "compiler/nir/nir.h"
#include "panfrost/util/pan_ir.h"
#include "util/u_math.h"
#include "util/half_float.h"

/* Swizzles across bytes in a 32-bit word. Expresses swz in the XML directly.
 * To express widen, use the correpsonding replicated form, i.e. H01 = identity
 * for widen = none, H00 for widen = h0, B1111 for widen = b1. For lane, also
 * use the replicated form (interpretation is governed by the opcode). For
 * 8-bit lanes with two channels, use replicated forms for replicated forms
 * (TODO: what about others?). For 8-bit lanes with four channels using
 * matching form (TODO: what about others?).
 */

enum bi_swizzle {
        /* 16-bit swizzle ordering deliberate for fast compute */
        BI_SWIZZLE_H00 = 0, /* = B0101 */
        BI_SWIZZLE_H01 = 1, /* = B0123 = W0 */
        BI_SWIZZLE_H10 = 2, /* = B2301 */
        BI_SWIZZLE_H11 = 3, /* = B2323 */

        /* replication order should be maintained for fast compute */
        BI_SWIZZLE_B0000 = 4, /* single channel (replicate) */
        BI_SWIZZLE_B1111 = 5,
        BI_SWIZZLE_B2222 = 6,
        BI_SWIZZLE_B3333 = 7,

        /* totally special for explicit pattern matching */
        BI_SWIZZLE_B0011 = 8, /* +SWZ.v4i8 */
        BI_SWIZZLE_B2233 = 9, /* +SWZ.v4i8 */
        BI_SWIZZLE_B1032 = 10, /* +SWZ.v4i8 */
        BI_SWIZZLE_B3210 = 11, /* +SWZ.v4i8 */

        BI_SWIZZLE_B0022 = 12, /* for b02 lanes */
};

enum bi_index_type {
        BI_INDEX_NULL = 0,
        BI_INDEX_NORMAL = 1,
        BI_INDEX_REGISTER = 2,
        BI_INDEX_CONSTANT = 3,
        BI_INDEX_PASS = 4,
        BI_INDEX_FAU = 5
};

typedef struct {
        uint32_t value;

        /* modifiers, should only be set if applicable for a given instruction.
         * For *IDP.v4i8, abs plays the role of sign. For bitwise ops where
         * applicable, neg plays the role of not */
        bool abs : 1;
        bool neg : 1;

        enum bi_swizzle swizzle : 4;
        uint32_t offset : 2;
        bool reg : 1;
        enum bi_index_type type : 3;
} bi_index;

static inline bi_index
bi_get_index(unsigned value, bool is_reg, unsigned offset)
{
        return (bi_index) {
                .type = BI_INDEX_NORMAL,
                .value = value,
                .swizzle = BI_SWIZZLE_H01,
                .offset = offset,
                .reg = is_reg,
        };
}

static inline bi_index
bi_register(unsigned reg)
{
        assert(reg < 64);

        return (bi_index) {
                .type = BI_INDEX_REGISTER,
                .swizzle = BI_SWIZZLE_H01,
                .value = reg
        };
}

static inline bi_index
bi_imm_u32(uint32_t imm)
{
        return (bi_index) {
                .type = BI_INDEX_CONSTANT,
                .swizzle = BI_SWIZZLE_H01,
                .value = imm
        };
}

static inline bi_index
bi_imm_f32(float imm)
{
        return bi_imm_u32(fui(imm));
}

static inline bi_index
bi_null()
{
        return (bi_index) { .type = BI_INDEX_NULL };
}

static inline bi_index
bi_zero()
{
        return bi_imm_u32(0);
}

static inline bi_index
bi_passthrough(enum bifrost_packed_src value)
{
        return (bi_index) {
                .type = BI_INDEX_PASS,
                .swizzle = BI_SWIZZLE_H01,
                .value = value
        };
}

/* Read back power-efficent garbage, TODO maybe merge with null? */
static inline bi_index
bi_dontcare()
{
        return bi_passthrough(BIFROST_SRC_FAU_HI);
}

/* Extracts a word from a vectored index */
static inline bi_index
bi_word(bi_index idx, unsigned component)
{
        idx.offset += component;
        return idx;
}

/* Helps construct swizzles */
static inline bi_index
bi_swz_16(bi_index idx, bool x, bool y)
{
        assert(idx.swizzle == BI_SWIZZLE_H01);
        idx.swizzle = BI_SWIZZLE_H00 | (x << 1) | y;
        return idx;
}

static inline bi_index
bi_half(bi_index idx, bool upper)
{
        return bi_swz_16(idx, upper, upper);
}

static inline bi_index
bi_byte(bi_index idx, unsigned lane)
{
        assert(idx.swizzle == BI_SWIZZLE_H01);
        assert(lane < 4);
        idx.swizzle = BI_SWIZZLE_B0000 + lane;
        return idx;
}

static inline bi_index
bi_abs(bi_index idx)
{
        idx.abs = true;
        return idx;
}

static inline bi_index
bi_neg(bi_index idx)
{
        idx.neg ^= true;
        return idx;
}

/* Additive identity in IEEE 754 arithmetic */
static inline bi_index
bi_negzero()
{
        return bi_neg(bi_zero());
}

/* Replaces an index, preserving any modifiers */

static inline bi_index
bi_replace_index(bi_index old, bi_index replacement)
{
        replacement.abs = old.abs;
        replacement.neg = old.neg;
        replacement.swizzle = old.swizzle;
        return replacement;
}

/* For bitwise instructions */
#define bi_not(x) bi_neg(x)

static inline bi_index
bi_imm_u8(uint8_t imm)
{
        return bi_byte(bi_imm_u32(imm), 0);
}

static inline bi_index
bi_imm_u16(uint16_t imm)
{
        return bi_half(bi_imm_u32(imm), false);
}

static inline bi_index
bi_imm_uintN(uint32_t imm, unsigned sz)
{
        assert(sz == 8 || sz == 16 || sz == 32);
        return (sz == 8) ? bi_imm_u8(imm) :
                (sz == 16) ? bi_imm_u16(imm) :
                bi_imm_u32(imm);
}

static inline bi_index
bi_imm_f16(float imm)
{
        return bi_imm_u16(_mesa_float_to_half(imm));
}

static inline bool
bi_is_null(bi_index idx)
{
        return idx.type == BI_INDEX_NULL;
}

static inline bool
bi_is_ssa(bi_index idx)
{
        return idx.type == BI_INDEX_NORMAL && !idx.reg;
}

/* Compares equivalence as references. Does not compare offsets, swizzles, or
 * modifiers. In other words, this forms bi_index equivalence classes by
 * partitioning memory. E.g. -abs(foo[1].yx) == foo.xy but foo != bar */

static inline bool
bi_is_equiv(bi_index left, bi_index right)
{
        return (left.type == right.type) &&
                (left.reg == right.reg) &&
                (left.value == right.value);
}

/* A stronger equivalence relation that requires the indices access the
 * same offset, useful for RA/scheduling to see what registers will
 * correspond to */

static inline bool
bi_is_word_equiv(bi_index left, bi_index right)
{
        return bi_is_equiv(left, right) && left.offset == right.offset;
}

#define BI_MAX_DESTS 2
#define BI_MAX_SRCS 4

typedef struct {
        /* Must be first */
        struct list_head link;

        /* Link for the use chain */
        struct list_head use;

        enum bi_opcode op;

        /* Data flow */
        bi_index dest[BI_MAX_DESTS];
        bi_index src[BI_MAX_SRCS];

        /* For a branch */
        struct bi_block *branch_target;

        /* These don't fit neatly with anything else.. */
        enum bi_register_format register_format;
        enum bi_vecsize vecsize;

        /* Can we spill the value written here? Used to prevent
         * useless double fills */
        bool no_spill;

        /* Override table, inducing a DTSEL_IMM pair if nonzero */
        enum bi_table table;

        /* Everything after this MUST NOT be accessed directly, since
         * interpretation depends on opcodes */

        /* Destination modifiers */
        union {
                enum bi_clamp clamp;
                bool saturate;
                bool not_result;
        };

        /* Immediates. All seen alone in an instruction, except for varying/texture
         * which are specified jointly for VARTEX */
        union {
                uint32_t shift;
                uint32_t fill;
                uint32_t index;
                uint32_t attribute_index;

                struct {
                        uint32_t varying_index;
                        uint32_t sampler_index;
                        uint32_t texture_index;
                };

                /* TEXC, ATOM_CX: # of staging registers used */
                uint32_t sr_count;
        };

        /* Modifiers specific to particular instructions are thrown in a union */
        union {
                enum bi_adj adj; /* FEXP_TABLE.u4 */
                enum bi_atom_opc atom_opc; /* atomics */
                enum bi_func func; /* FPOW_SC_DET */
                enum bi_function function; /* LD_VAR_FLAT */
                enum bi_mux mux; /* MUX */
                enum bi_sem sem; /* FMAX, FMIN */
                enum bi_source source; /* LD_GCLK */
                bool scale; /* VN_ASST2, FSINCOS_OFFSET */
                bool offset; /* FSIN_TABLE, FOCS_TABLE */
                bool mask; /* CLZ */
                bool threads; /* IMULD, IMOV_FMA */
                bool combine; /* BRANCHC */
                bool format; /* LEA_TEX */

                struct {
                        bool skip; /* VAR_TEX, TEXS, TEXC */
                        bool lod_mode; /* TEXS */
                };

                struct {
                        enum bi_special special; /* FADD_RSCALE, FMA_RSCALE */
                        enum bi_round round; /* FMA, converts, FADD, _RSCALE, etc */
                };

                struct {
                        enum bi_result_type result_type; /* FCMP, ICMP */
                        enum bi_cmpf cmpf; /* CSEL, FCMP, ICMP, BRANCH */
                };

                struct {
                        enum bi_stack_mode stack_mode; /* JUMP_EX */
                        bool test_mode;
                };

                struct {
                        enum bi_seg seg; /* LOAD, STORE, SEG_ADD, SEG_SUB */
                        bool preserve_null; /* SEG_ADD, SEG_SUB */
                        enum bi_extend extend; /* LOAD, IMUL */
                };

                struct {
                        enum bi_sample sample; /* LD_VAR */
                        enum bi_update update; /* LD_VAR */
                        enum bi_varying_name varying_name; /* LD_VAR_SPECIAL */
                };

                struct {
                        enum bi_subgroup subgroup; /* WMASK, CLPER */
                        enum bi_inactive_result inactive_result; /* CLPER */
                        enum bi_lane_op lane_op; /* CLPER */
                };

                struct {
                        bool z; /* ZS_EMIT */
                        bool stencil; /* ZS_EMIT */
                };

                struct {
                        bool h; /* VN_ASST1.f16 */
                        bool l; /* VN_ASST1.f16 */
                };

                struct {
                        bool bytes2; /* RROT_DOUBLE, FRSHIFT_DOUBLE */
                        bool result_word;
                };

                struct {
                        bool sqrt; /* FREXPM */
                        bool log; /* FREXPM */
                };

                struct {
                        enum bi_mode mode; /* FLOG_TABLE */
                        enum bi_precision precision; /* FLOG_TABLE */
                        bool divzero; /* FRSQ_APPROX, FRSQ */
                };
        };
} bi_instr;

/* Represents the assignment of slots for a given bi_tuple */

typedef struct {
        /* Register to assign to each slot */
        unsigned slot[4];

        /* Read slots can be disabled */
        bool enabled[2];

        /* Configuration for slots 2/3 */
        struct bifrost_reg_ctrl_23 slot23;

        /* Fast-Access-Uniform RAM index */
        uint8_t fau_idx;

        /* Whether writes are actually for the last instruction */
        bool first_instruction;
} bi_registers;

/* A bi_tuple contains two paired instruction pointers. If a slot is unfilled,
 * leave it NULL; the emitter will fill in a nop. Instructions reference
 * registers via slots which are assigned per tuple.
 */

typedef struct {
        uint8_t fau_idx;
        bi_registers regs;
        bi_instr *fma;
        bi_instr *add;
} bi_tuple;

struct bi_block;

typedef struct {
        struct list_head link;

        /* Link back up for branch calculations */
        struct bi_block *block;

        /* Architectural limit of 8 tuples/clause */
        unsigned tuple_count;
        bi_tuple tuples[8];

        /* For scoreboarding -- the clause ID (this is not globally unique!)
         * and its dependencies in terms of other clauses, computed during
         * scheduling and used when emitting code. Dependencies expressed as a
         * bitfield matching the hardware, except shifted by a clause (the
         * shift back to the ISA's off-by-one encoding is worked out when
         * emitting clauses) */
        unsigned scoreboard_id;
        uint8_t dependencies;

        /* See ISA header for description */
        enum bifrost_flow flow_control;

        /* Can we prefetch the next clause? Usually it makes sense, except for
         * clauses ending in unconditional branches */
        bool next_clause_prefetch;

        /* Assigned data register */
        unsigned staging_register;

        /* Corresponds to the usual bit but shifted by a clause */
        bool staging_barrier;

        /* Constants read by this clause. ISA limit. Must satisfy:
         *
         *      constant_count + tuple_count <= 13
         *
         * Also implicitly constant_count <= tuple_count since a tuple only
         * reads a single constant.
         */
        uint64_t constants[8];
        unsigned constant_count;

        /* Index of a constant to be PC-relative */
        unsigned pcrel_idx;

        /* Branches encode a constant offset relative to the program counter
         * with some magic flags. By convention, if there is a branch, its
         * constant will be last. Set this flag to indicate this is required.
         */
        bool branch_constant;

        /* Unique in a clause */
        enum bifrost_message_type message_type;
        bi_instr *message;
} bi_clause;

typedef struct bi_block {
        pan_block base; /* must be first */

        /* If true, uses clauses; if false, uses instructions */
        bool scheduled;
        struct list_head clauses; /* list of bi_clause */
} bi_block;

typedef struct {
       const struct panfrost_compile_inputs *inputs;
       nir_shader *nir;
       struct pan_shader_info *info;
       gl_shader_stage stage;
       struct list_head blocks; /* list of bi_block */
       struct hash_table_u64 *sysval_to_id;
       uint32_t quirks;
       unsigned arch;

       /* During NIR->BIR */
       bi_block *current_block;
       bi_block *after_block;
       bi_block *break_block;
       bi_block *continue_block;
       bool emitted_atest;

       /* For creating temporaries */
       unsigned ssa_alloc;
       unsigned reg_alloc;

       /* Analysis results */
       bool has_liveness;

       /* Stats for shader-db */
       unsigned instruction_count;
       unsigned loop_count;
       unsigned spills;
       unsigned fills;
} bi_context;

static inline void
bi_remove_instruction(bi_instr *ins)
{
        list_del(&ins->link);
}

enum bir_fau {
        BIR_FAU_ZERO = 0,
        BIR_FAU_LANE_ID = 1,
        BIR_FAU_WRAP_ID = 2,
        BIR_FAU_CORE_ID = 3,
        BIR_FAU_FB_EXTENT = 4,
        BIR_FAU_ATEST_PARAM = 5,
        BIR_FAU_SAMPLE_POS_ARRAY = 6,
        BIR_FAU_BLEND_0 = 8,
        /* blend descs 1 - 7 */
        BIR_FAU_TYPE_MASK = 15,
        BIR_FAU_UNIFORM = (1 << 7),
        BIR_FAU_HI = (1 << 8),
};

static inline bi_index
bi_fau(enum bir_fau value, bool hi)
{
        return (bi_index) {
                .type = BI_INDEX_FAU,
                .value = value,
                .swizzle = BI_SWIZZLE_H01,
                .offset = hi ? 1 : 0
        };
}

static inline unsigned
bi_max_temp(bi_context *ctx)
{
        return (MAX2(ctx->reg_alloc, ctx->ssa_alloc) + 2) << 1;
}

static inline bi_index
bi_temp(bi_context *ctx)
{
        return bi_get_index(ctx->ssa_alloc++, false, 0);
}

static inline bi_index
bi_temp_reg(bi_context *ctx)
{
        return bi_get_index(ctx->reg_alloc++, true, 0);
}

/* Inline constants automatically, will be lowered out by bi_lower_fau where a
 * constant is not allowed. load_const_to_scalar gaurantees that this makes
 * sense */

static inline bi_index
bi_src_index(nir_src *src)
{
        if (nir_src_is_const(*src) && nir_src_bit_size(*src) <= 32)
                return bi_imm_u32(nir_src_as_uint(*src));
        else if (src->is_ssa)
                return bi_get_index(src->ssa->index, false, 0);
        else {
                assert(!src->reg.indirect);
                return bi_get_index(src->reg.reg->index, true, 0);
        }
}

static inline bi_index
bi_dest_index(nir_dest *dst)
{
        if (dst->is_ssa)
                return bi_get_index(dst->ssa.index, false, 0);
        else {
                assert(!dst->reg.indirect);
                return bi_get_index(dst->reg.reg->index, true, 0);
        }
}

static inline unsigned
bi_get_node(bi_index index)
{
        if (bi_is_null(index) || index.type != BI_INDEX_NORMAL)
                return ~0;
        else
                return (index.value << 1) | index.reg;
}

static inline bi_index
bi_node_to_index(unsigned node, unsigned node_count)
{
        assert(node < node_count);
        assert(node_count < ~0);

        return bi_get_index(node >> 1, node & PAN_IS_REG, 0);
}

/* Iterators for Bifrost IR */

#define bi_foreach_block(ctx, v) \
        list_for_each_entry(pan_block, v, &ctx->blocks, link)

#define bi_foreach_block_rev(ctx, v) \
        list_for_each_entry_rev(pan_block, v, &ctx->blocks, link)

#define bi_foreach_block_from(ctx, from, v) \
        list_for_each_entry_from(pan_block, v, from, &ctx->blocks, link)

#define bi_foreach_block_from_rev(ctx, from, v) \
        list_for_each_entry_from_rev(pan_block, v, from, &ctx->blocks, link)

#define bi_foreach_instr_in_block(block, v) \
        list_for_each_entry(bi_instr, v, &(block)->base.instructions, link)

#define bi_foreach_instr_in_block_rev(block, v) \
        list_for_each_entry_rev(bi_instr, v, &(block)->base.instructions, link)

#define bi_foreach_instr_in_block_safe(block, v) \
        list_for_each_entry_safe(bi_instr, v, &(block)->base.instructions, link)

#define bi_foreach_instr_in_block_safe_rev(block, v) \
        list_for_each_entry_safe_rev(bi_instr, v, &(block)->base.instructions, link)

#define bi_foreach_instr_in_block_from(block, v, from) \
        list_for_each_entry_from(bi_instr, v, from, &(block)->base.instructions, link)

#define bi_foreach_instr_in_block_from_rev(block, v, from) \
        list_for_each_entry_from_rev(bi_instr, v, from, &(block)->base.instructions, link)

#define bi_foreach_clause_in_block(block, v) \
        list_for_each_entry(bi_clause, v, &(block)->clauses, link)

#define bi_foreach_clause_in_block_rev(block, v) \
        list_for_each_entry_rev(bi_clause, v, &(block)->clauses, link)

#define bi_foreach_clause_in_block_safe(block, v) \
        list_for_each_entry_safe(bi_clause, v, &(block)->clauses, link)

#define bi_foreach_clause_in_block_from(block, v, from) \
        list_for_each_entry_from(bi_clause, v, from, &(block)->clauses, link)

#define bi_foreach_clause_in_block_from_rev(block, v, from) \
        list_for_each_entry_from_rev(bi_clause, v, from, &(block)->clauses, link)

#define bi_foreach_instr_global(ctx, v) \
        bi_foreach_block(ctx, v_block) \
                bi_foreach_instr_in_block((bi_block *) v_block, v)

#define bi_foreach_instr_global_safe(ctx, v) \
        bi_foreach_block(ctx, v_block) \
                bi_foreach_instr_in_block_safe((bi_block *) v_block, v)

#define bi_foreach_instr_in_tuple(tuple, v) \
        for (bi_instr *v = tuple->fma ?: tuple->add; \
                        v != NULL; \
                        v = (v == tuple->add) ? NULL : tuple->add)

/* Based on set_foreach, expanded with automatic type casts */

#define bi_foreach_predecessor(blk, v) \
        struct set_entry *_entry_##v; \
        bi_block *v; \
        for (_entry_##v = _mesa_set_next_entry(blk->base.predecessors, NULL), \
                v = (bi_block *) (_entry_##v ? _entry_##v->key : NULL);  \
                _entry_##v != NULL; \
                _entry_##v = _mesa_set_next_entry(blk->base.predecessors, _entry_##v), \
                v = (bi_block *) (_entry_##v ? _entry_##v->key : NULL))

#define bi_foreach_src(ins, v) \
        for (unsigned v = 0; v < ARRAY_SIZE(ins->src); ++v)

#define bi_foreach_dest(ins, v) \
        for (unsigned v = 0; v < ARRAY_SIZE(ins->dest); ++v)

#define bi_foreach_instr_and_src_in_tuple(tuple, ins, s) \
        bi_foreach_instr_in_tuple(tuple, ins) \
                bi_foreach_src(ins, s)

static inline bi_instr *
bi_prev_op(bi_instr *ins)
{
        return list_last_entry(&(ins->link), bi_instr, link);
}

static inline bi_instr *
bi_next_op(bi_instr *ins)
{
        return list_first_entry(&(ins->link), bi_instr, link);
}

static inline pan_block *
pan_next_block(pan_block *block)
{
        return list_first_entry(&(block->link), pan_block, link);
}

/* BIR manipulation */

bool bi_has_arg(bi_instr *ins, bi_index arg);
unsigned bi_count_read_registers(bi_instr *ins, unsigned src);
unsigned bi_writemask(bi_instr *ins, unsigned dest);
bi_clause * bi_next_clause(bi_context *ctx, pan_block *block, bi_clause *clause);
bool bi_side_effects(enum bi_opcode op);

void bi_print_instr(bi_instr *I, FILE *fp);
void bi_print_slots(bi_registers *regs, FILE *fp);
void bi_print_tuple(bi_tuple *tuple, FILE *fp);
void bi_print_clause(bi_clause *clause, FILE *fp);
void bi_print_block(bi_block *block, FILE *fp);
void bi_print_shader(bi_context *ctx, FILE *fp);

/* BIR passes */

void bi_opt_copy_prop(bi_context *ctx);
void bi_opt_dead_code_eliminate(bi_context *ctx, bool soft);
void bi_opt_push_ubo(bi_context *ctx);
void bi_opt_constant_fold(bi_context *ctx);
void bi_lower_swizzle(bi_context *ctx);
void bi_schedule(bi_context *ctx);
void bi_assign_scoreboard(bi_context *ctx);
void bi_register_allocate(bi_context *ctx);

/* Test suite */
int bi_test_scheduler(void);
int bi_test_packing(void);
int bi_test_packing_formats(void);

bi_clause *
bi_singleton(void *memctx, bi_instr *ins,
                bi_block *block,
                unsigned scoreboard_id,
                unsigned dependencies,
                uint64_t combined_constant,
                bool osrb);

/* Liveness */

void bi_compute_liveness(bi_context *ctx);
void bi_liveness_ins_update(uint16_t *live, bi_instr *ins, unsigned max);
void bi_invalidate_liveness(bi_context *ctx);

/* Layout */

bool bi_can_insert_tuple(bi_clause *clause, bool constant);
unsigned bi_clause_quadwords(bi_clause *clause);
signed bi_block_offset(bi_context *ctx, bi_clause *start, bi_block *target);
bool bi_ec0_packed(unsigned tuple_count);

/* Check if there are no more instructions starting with a given block, this
 * needs to recurse in case a shader ends with multiple empty blocks */

static inline bool
bi_is_terminal_block(bi_block *block)
{
        return (block == NULL) ||
                (list_is_empty(&block->base.instructions) &&
                 bi_is_terminal_block((bi_block *) block->base.successors[0]) &&
                 bi_is_terminal_block((bi_block *) block->base.successors[1]));
}

/* Code emit */

/* Returns the size of the final clause */
unsigned bi_pack(bi_context *ctx, struct util_dynarray *emission);

struct bi_packed_tuple {
        uint64_t lo;
        uint64_t hi;
};

void
bi_pack_format(struct util_dynarray *emission,
                unsigned index,
                struct bi_packed_tuple *tuples,
                ASSERTED unsigned tuple_count,
                uint64_t header, uint64_t ec0,
                unsigned m0, bool z);

unsigned bi_pack_fma(bi_instr *I,
                enum bifrost_packed_src src0,
                enum bifrost_packed_src src1,
                enum bifrost_packed_src src2,
                enum bifrost_packed_src src3);
unsigned bi_pack_add(bi_instr *I,
                enum bifrost_packed_src src0,
                enum bifrost_packed_src src1,
                enum bifrost_packed_src src2,
                enum bifrost_packed_src src3);

/* Like in NIR, for use with the builder */

enum bi_cursor_option {
    bi_cursor_after_block,
    bi_cursor_before_instr,
    bi_cursor_after_instr
};

typedef struct {
    enum bi_cursor_option option;

    union {
        bi_block *block;
        bi_instr *instr;
    };
} bi_cursor;

static inline bi_cursor
bi_after_block(bi_block *block)
{
    return (bi_cursor) {
        .option = bi_cursor_after_block,
        .block = block
    };
}

static inline bi_cursor
bi_before_instr(bi_instr *instr)
{
    return (bi_cursor) {
        .option = bi_cursor_before_instr,
        .instr = instr
    };
}

static inline bi_cursor
bi_after_instr(bi_instr *instr)
{
    return (bi_cursor) {
        .option = bi_cursor_after_instr,
        .instr = instr
    };
}

/* Invariant: a tuple must be nonempty UNLESS it is the last tuple of a clause,
 * in which case there must exist a nonempty penultimate tuple */

ATTRIBUTE_RETURNS_NONNULL static inline bi_instr *
bi_first_instr_in_clause(bi_clause *clause)
{
        bi_tuple tuple = clause->tuples[0];
        bi_instr *instr = tuple.fma ?: tuple.add;

        assert(instr != NULL);
        return instr;
}

ATTRIBUTE_RETURNS_NONNULL static inline bi_instr *
bi_last_instr_in_clause(bi_clause *clause)
{
        bi_tuple tuple = clause->tuples[clause->tuple_count - 1];
        bi_instr *instr = tuple.add ?: tuple.fma;

        if (!instr) {
                assert(clause->tuple_count >= 2);
                tuple = clause->tuples[clause->tuple_count - 2];
                instr = tuple.add ?: tuple.fma;
        }

        assert(instr != NULL);
        return instr;
}

/* Implemented by expanding bi_foreach_instr_in_block_from(_rev) with the start
 * (end) of the clause and adding a condition for the clause boundary */

#define bi_foreach_instr_in_clause(block, clause, pos) \
   for (bi_instr *pos = LIST_ENTRY(bi_instr, bi_first_instr_in_clause(clause), link); \
	(&pos->link != &(block)->base.instructions) \
                && (pos != bi_next_op(bi_last_instr_in_clause(clause))); \
	pos = LIST_ENTRY(bi_instr, pos->link.next, link))

#define bi_foreach_instr_in_clause_rev(block, clause, pos) \
   for (bi_instr *pos = LIST_ENTRY(bi_instr, bi_last_instr_in_clause(clause), link); \
	(&pos->link != &(block)->base.instructions) \
	        && pos != bi_prev_op(bi_first_instr_in_clause(clause)); \
	pos = LIST_ENTRY(bi_instr, pos->link.prev, link))

static inline bi_cursor
bi_before_clause(bi_clause *clause)
{
    return bi_before_instr(bi_first_instr_in_clause(clause));
}

static inline bi_cursor
bi_after_clause(bi_clause *clause)
{
    return bi_after_instr(bi_last_instr_in_clause(clause));
}

/* IR builder in terms of cursor infrastructure */

typedef struct {
    bi_context *shader;
    bi_cursor cursor;
} bi_builder;

static inline bi_builder
bi_init_builder(bi_context *ctx, bi_cursor cursor)
{
        return (bi_builder) {
                .shader = ctx,
                .cursor = cursor
        };
}

/* Insert an instruction at the cursor and move the cursor */

static inline void
bi_builder_insert(bi_cursor *cursor, bi_instr *I)
{
    switch (cursor->option) {
    case bi_cursor_after_instr:
        list_add(&I->link, &cursor->instr->link);
        cursor->instr = I;
        return;

    case bi_cursor_after_block:
        list_addtail(&I->link, &cursor->block->base.instructions);
        cursor->option = bi_cursor_after_instr;
        cursor->instr = I;
        return;

    case bi_cursor_before_instr:
        list_addtail(&I->link, &cursor->instr->link);
        cursor->option = bi_cursor_after_instr;
        cursor->instr = I;
        return;
    }

    unreachable("Invalid cursor option");
}

#endif