ir3: Support variants with different constlen's

[mesa.git] / src / freedreno / ir3 / ir3_shader.h

/*
 * Copyright (C) 2014 Rob Clark <robclark@freedesktop.org>
 *
 * 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 <robclark@freedesktop.org>
 */

#ifndef IR3_SHADER_H_
#define IR3_SHADER_H_

#include <stdio.h>

#include "c11/threads.h"
#include "compiler/shader_enums.h"
#include "compiler/nir/nir.h"
#include "util/bitscan.h"

#include "ir3_compiler.h"

struct glsl_type;

/* driver param indices: */
enum ir3_driver_param {
        /* compute shader driver params: */
        IR3_DP_NUM_WORK_GROUPS_X = 0,
        IR3_DP_NUM_WORK_GROUPS_Y = 1,
        IR3_DP_NUM_WORK_GROUPS_Z = 2,
        IR3_DP_LOCAL_GROUP_SIZE_X = 4,
        IR3_DP_LOCAL_GROUP_SIZE_Y = 5,
        IR3_DP_LOCAL_GROUP_SIZE_Z = 6,
        /* NOTE: gl_NumWorkGroups should be vec4 aligned because
         * glDispatchComputeIndirect() needs to load these from
         * the info->indirect buffer.  Keep that in mind when/if
         * adding any addition CS driver params.
         */
        IR3_DP_CS_COUNT   = 8,   /* must be aligned to vec4 */

        /* vertex shader driver params: */
        IR3_DP_DRAWID = 0,
        IR3_DP_VTXID_BASE = 1,
        IR3_DP_INSTID_BASE = 2,
        IR3_DP_VTXCNT_MAX = 3,
        /* user-clip-plane components, up to 8x vec4's: */
        IR3_DP_UCP0_X     = 4,
        /* .... */
        IR3_DP_UCP7_W     = 35,
        IR3_DP_VS_COUNT   = 36   /* must be aligned to vec4 */
};

#define IR3_MAX_SHADER_BUFFERS   32
#define IR3_MAX_SHADER_IMAGES    32
#define IR3_MAX_SO_BUFFERS        4
#define IR3_MAX_SO_STREAMS        4
#define IR3_MAX_SO_OUTPUTS       64
#define IR3_MAX_UBO_PUSH_RANGES  32

/**
 * Description of a lowered UBO.
 */
struct ir3_ubo_info {
        uint32_t block; /* Which constant block */
        uint16_t bindless_base; /* For bindless, which base register is used */
        bool bindless;
};

/**
 * Description of a range of a lowered UBO access.
 *
 * Drivers should not assume that there are not multiple disjoint
 * lowered ranges of a single UBO.
 */
struct ir3_ubo_range {
        struct ir3_ubo_info ubo;
        uint32_t offset; /* start offset to push in the const register file */
        uint32_t start, end; /* range of block that's actually used */
};

struct ir3_ubo_analysis_state {
        struct ir3_ubo_range range[IR3_MAX_UBO_PUSH_RANGES];
        uint32_t num_enabled;
        uint32_t size;
        uint32_t cmdstream_size; /* for per-gen backend to stash required cmdstream size */
};

/**
 * Describes the layout of shader consts.  This includes:
 *   + User consts + driver lowered UBO ranges
 *   + SSBO sizes
 *   + Image sizes/dimensions
 *   + Driver params (ie. IR3_DP_*)
 *   + TFBO addresses (for generations that do not have hardware streamout)
 *   + Lowered immediates
 *
 * For consts needed to pass internal values to shader which may or may not
 * be required, rather than allocating worst-case const space, we scan the
 * shader and allocate consts as-needed:
 *
 *   + SSBO sizes: only needed if shader has a get_buffer_size intrinsic
 *     for a given SSBO
 *
 *   + Image dimensions: needed to calculate pixel offset, but only for
 *     images that have a image_store intrinsic
 *
 * Layout of constant registers, each section aligned to vec4.  Note
 * that pointer size (ubo, etc) changes depending on generation.
 *
 *    user consts
 *    UBO addresses
 *    SSBO sizes
 *    if (vertex shader) {
 *        driver params (IR3_DP_*)
 *        if (stream_output.num_outputs > 0)
 *           stream-out addresses
 *    } else if (compute_shader) {
 *        driver params (IR3_DP_*)
 *    }
 *    immediates
 *
 * Immediates go last mostly because they are inserted in the CP pass
 * after the nir -> ir3 frontend.
 *
 * Note UBO size in bytes should be aligned to vec4
 */
struct ir3_const_state {
        unsigned num_ubos;
        unsigned num_driver_params;   /* scalar */

        struct {
                /* user const start at zero */
                unsigned ubo;
                /* NOTE that a3xx might need a section for SSBO addresses too */
                unsigned ssbo_sizes;
                unsigned image_dims;
                unsigned driver_param;
                unsigned tfbo;
                unsigned primitive_param;
                unsigned primitive_map;
                unsigned immediate;
        } offsets;

        struct {
                uint32_t mask;  /* bitmask of SSBOs that have get_buffer_size */
                uint32_t count; /* number of consts allocated */
                /* one const allocated per SSBO which has get_buffer_size,
                 * ssbo_sizes.off[ssbo_id] is offset from start of ssbo_sizes
                 * consts:
                 */
                uint32_t off[IR3_MAX_SHADER_BUFFERS];
        } ssbo_size;

        struct {
                uint32_t mask;  /* bitmask of images that have image_store */
                uint32_t count; /* number of consts allocated */
                /* three const allocated per image which has image_store:
                 *  + cpp         (bytes per pixel)
                 *  + pitch       (y pitch)
                 *  + array_pitch (z pitch)
                 */
                uint32_t off[IR3_MAX_SHADER_IMAGES];
        } image_dims;

        unsigned immediate_idx;
        unsigned immediates_count;
        unsigned immediates_size;
        struct {
                uint32_t val[4];
        } *immediates;

        /* State of ubo access lowered to push consts: */
        struct ir3_ubo_analysis_state ubo_state;
};

/**
 * A single output for vertex transform feedback.
 */
struct ir3_stream_output {
        unsigned register_index:6;  /**< 0 to 63 (OUT index) */
        unsigned start_component:2; /** 0 to 3 */
        unsigned num_components:3;  /** 1 to 4 */
        unsigned output_buffer:3;   /**< 0 to PIPE_MAX_SO_BUFFERS */
        unsigned dst_offset:16;     /**< offset into the buffer in dwords */
        unsigned stream:2;          /**< 0 to 3 */
};

/**
 * Stream output for vertex transform feedback.
 */
struct ir3_stream_output_info {
        unsigned num_outputs;
        /** stride for an entire vertex for each buffer in dwords */
        uint16_t stride[IR3_MAX_SO_BUFFERS];

        /**
         * Array of stream outputs, in the order they are to be written in.
         * Selected components are tightly packed into the output buffer.
         */
        struct ir3_stream_output output[IR3_MAX_SO_OUTPUTS];
};


/**
 * Starting from a4xx, HW supports pre-dispatching texture sampling
 * instructions prior to scheduling a shader stage, when the
 * coordinate maps exactly to an output of the previous stage.
 */

/**
 * There is a limit in the number of pre-dispatches allowed for any
 * given stage.
 */
#define IR3_MAX_SAMPLER_PREFETCH 4

/**
 * This is the output stream value for 'cmd', as used by blob. It may
 * encode the return type (in 3 bits) but it hasn't been verified yet.
 */
#define IR3_SAMPLER_PREFETCH_CMD 0x4
#define IR3_SAMPLER_BINDLESS_PREFETCH_CMD 0x6

/**
 * Stream output for texture sampling pre-dispatches.
 */
struct ir3_sampler_prefetch {
        uint8_t src;
        uint8_t samp_id;
        uint8_t tex_id;
        uint16_t samp_bindless_id;
        uint16_t tex_bindless_id;
        uint8_t dst;
        uint8_t wrmask;
        uint8_t half_precision;
        uint8_t cmd;
};


/* Configuration key used to identify a shader variant.. different
 * shader variants can be used to implement features not supported
 * in hw (two sided color), binning-pass vertex shader, etc.
 *
 * When adding to this struct, please update ir3_shader_variant()'s debug
 * output.
 */
struct ir3_shader_key {
        union {
                struct {
                        /*
                         * Combined Vertex/Fragment shader parameters:
                         */
                        unsigned ucp_enables : 8;

                        /* do we need to check {v,f}saturate_{s,t,r}? */
                        unsigned has_per_samp : 1;

                        /*
                         * Vertex shader variant parameters:
                         */
                        unsigned vclamp_color : 1;

                        /*
                         * Fragment shader variant parameters:
                         */
                        unsigned sample_shading : 1;
                        unsigned msaa           : 1;
                        unsigned color_two_side : 1;
                        /* used when shader needs to handle flat varyings (a4xx)
                         * for front/back color inputs to frag shader:
                         */
                        unsigned rasterflat : 1;
                        unsigned fclamp_color : 1;

                        /* Indicates that this is a tessellation pipeline which requires a
                         * whole different kind of vertex shader.  In case of
                         * tessellation, this field also tells us which kind of output
                         * topology the TES uses, which the TCS needs to know.
                         */
#define IR3_TESS_NONE           0
#define IR3_TESS_TRIANGLES      1
#define IR3_TESS_QUADS          2
#define IR3_TESS_ISOLINES       3
                        unsigned tessellation : 2;

                        unsigned has_gs : 1;

                        /* Whether this variant sticks to the "safe" maximum constlen,
                         * which guarantees that the combined stages will never go over
                         * the limit:
                         */
                        unsigned safe_constlen : 1;
                };
                uint32_t global;
        };

        /* bitmask of sampler which needs coords clamped for vertex
         * shader:
         */
        uint16_t vsaturate_s, vsaturate_t, vsaturate_r;

        /* bitmask of sampler which needs coords clamped for frag
         * shader:
         */
        uint16_t fsaturate_s, fsaturate_t, fsaturate_r;

        /* bitmask of ms shifts */
        uint32_t vsamples, fsamples;

        /* bitmask of samplers which need astc srgb workaround: */
        uint16_t vastc_srgb, fastc_srgb;
};

static inline unsigned
ir3_tess_mode(unsigned gl_tess_mode)
{
        switch (gl_tess_mode) {
        case GL_ISOLINES:
                return  IR3_TESS_ISOLINES;
        case GL_TRIANGLES:
                return IR3_TESS_TRIANGLES;
        case GL_QUADS:
                return IR3_TESS_QUADS;
        default:
                unreachable("bad tessmode");
        }
}

static inline bool
ir3_shader_key_equal(const struct ir3_shader_key *a, const struct ir3_shader_key *b)
{
        /* slow-path if we need to check {v,f}saturate_{s,t,r} */
        if (a->has_per_samp || b->has_per_samp)
                return memcmp(a, b, sizeof(struct ir3_shader_key)) == 0;
        return a->global == b->global;
}

/* will the two keys produce different lowering for a fragment shader? */
static inline bool
ir3_shader_key_changes_fs(struct ir3_shader_key *key, struct ir3_shader_key *last_key)
{
        if (last_key->has_per_samp || key->has_per_samp) {
                if ((last_key->fsaturate_s != key->fsaturate_s) ||
                                (last_key->fsaturate_t != key->fsaturate_t) ||
                                (last_key->fsaturate_r != key->fsaturate_r) ||
                                (last_key->fsamples != key->fsamples) ||
                                (last_key->fastc_srgb != key->fastc_srgb))
                        return true;
        }

        if (last_key->fclamp_color != key->fclamp_color)
                return true;

        if (last_key->color_two_side != key->color_two_side)
                return true;

        if (last_key->rasterflat != key->rasterflat)
                return true;

        if (last_key->ucp_enables != key->ucp_enables)
                return true;

        if (last_key->safe_constlen != key->safe_constlen)
                return true;

        return false;
}

/* will the two keys produce different lowering for a vertex shader? */
static inline bool
ir3_shader_key_changes_vs(struct ir3_shader_key *key, struct ir3_shader_key *last_key)
{
        if (last_key->has_per_samp || key->has_per_samp) {
                if ((last_key->vsaturate_s != key->vsaturate_s) ||
                                (last_key->vsaturate_t != key->vsaturate_t) ||
                                (last_key->vsaturate_r != key->vsaturate_r) ||
                                (last_key->vsamples != key->vsamples) ||
                                (last_key->vastc_srgb != key->vastc_srgb))
                        return true;
        }

        if (last_key->vclamp_color != key->vclamp_color)
                return true;

        if (last_key->ucp_enables != key->ucp_enables)
                return true;

        if (last_key->safe_constlen != key->safe_constlen)
                return true;

        return false;
}

/**
 * On a4xx+a5xx, Images share state with textures and SSBOs:
 *
 *   + Uses texture (cat5) state/instruction (isam) to read
 *   + Uses SSBO state and instructions (cat6) to write and for atomics
 *
 * Starting with a6xx, Images and SSBOs are basically the same thing,
 * with texture state and isam also used for SSBO reads.
 *
 * On top of that, gallium makes the SSBO (shader_buffers) state semi
 * sparse, with the first half of the state space used for atomic
 * counters lowered to atomic buffers.  We could ignore this, but I
 * don't think we could *really* handle the case of a single shader
 * that used the max # of textures + images + SSBOs.  And once we are
 * offsetting images by num_ssbos (or visa versa) to map them into
 * the same hardware state, the hardware state has become coupled to
 * the shader state, so at this point we might as well just use a
 * mapping table to remap things from image/SSBO idx to hw idx.
 *
 * To make things less (more?) confusing, for the hw "SSBO" state
 * (since it is really both SSBO and Image) I'll use the name "IBO"
 */
struct ir3_ibo_mapping {
#define IBO_INVALID 0xff
        /* Maps logical SSBO state to hw tex state: */
        uint8_t ssbo_to_tex[IR3_MAX_SHADER_BUFFERS];

        /* Maps logical Image state to hw tex state: */
        uint8_t image_to_tex[IR3_MAX_SHADER_IMAGES];

        /* Maps hw state back to logical SSBO or Image state:
         *
         * note IBO_SSBO ORd into values to indicate that the
         * hw slot is used for SSBO state vs Image state.
         */
#define IBO_SSBO    0x80
        uint8_t tex_to_image[32];

        uint8_t num_tex;    /* including real textures */
        uint8_t tex_base;   /* the number of real textures, ie. image/ssbo start here */
};

/* Represents half register in regid */
#define HALF_REG_ID    0x100

struct ir3_shader_variant {
        struct fd_bo *bo;

        /* variant id (for debug) */
        uint32_t id;

        struct ir3_shader_key key;

        /* vertex shaders can have an extra version for hwbinning pass,
         * which is pointed to by so->binning:
         */
        bool binning_pass;
//      union {
                struct ir3_shader_variant *binning;
                struct ir3_shader_variant *nonbinning;
//      };

        struct ir3_info info;
        struct ir3 *ir;

        /* The actual binary shader instructions, size given by info.sizedwords: */
        uint32_t *bin;

        /* Levels of nesting of flow control:
         */
        unsigned branchstack;

        unsigned max_sun;
        unsigned loops;

        /* the instructions length is in units of instruction groups
         * (4 instructions for a3xx, 16 instructions for a4xx.. each
         * instruction is 2 dwords):
         */
        unsigned instrlen;

        /* the constants length is in units of vec4's, and is the sum of
         * the uniforms and the built-in compiler constants
         */
        unsigned constlen;

        struct ir3_const_state *const_state;

        /* About Linkage:
         *   + Let the frag shader determine the position/compmask for the
         *     varyings, since it is the place where we know if the varying
         *     is actually used, and if so, which components are used.  So
         *     what the hw calls "outloc" is taken from the "inloc" of the
         *     frag shader.
         *   + From the vert shader, we only need the output regid
         */

        bool frag_face, color0_mrt;
        uint8_t fragcoord_compmask;

        /* NOTE: for input/outputs, slot is:
         *   gl_vert_attrib  - for VS inputs
         *   gl_varying_slot - for VS output / FS input
         *   gl_frag_result  - for FS output
         */

        /* varyings/outputs: */
        unsigned outputs_count;
        struct {
                uint8_t slot;
                uint8_t regid;
                bool    half : 1;
        } outputs[32 + 2];  /* +POSITION +PSIZE */
        bool writes_pos, writes_smask, writes_psize;

        /* Size in dwords of all outputs for VS, size of entire patch for HS. */
        uint32_t output_size;

        /* Map from driver_location to byte offset in per-primitive storage */
        unsigned output_loc[32];

        /* attributes (VS) / varyings (FS):
         * Note that sysval's should come *after* normal inputs.
         */
        unsigned inputs_count;
        struct {
                uint8_t slot;
                uint8_t regid;
                uint8_t compmask;
                /* location of input (ie. offset passed to bary.f, etc).  This
                 * matches the SP_VS_VPC_DST_REG.OUTLOCn value (a3xx and a4xx
                 * have the OUTLOCn value offset by 8, presumably to account
                 * for gl_Position/gl_PointSize)
                 */
                uint8_t inloc;
                /* vertex shader specific: */
                bool    sysval     : 1;   /* slot is a gl_system_value */
                /* fragment shader specific: */
                bool    bary       : 1;   /* fetched varying (vs one loaded into reg) */
                bool    rasterflat : 1;   /* special handling for emit->rasterflat */
                bool    use_ldlv   : 1;   /* internal to ir3_compiler_nir */
                bool    half       : 1;
                enum glsl_interp_mode interpolate;
        } inputs[32 + 2];  /* +POSITION +FACE */

        /* sum of input components (scalar).  For frag shaders, it only counts
         * the varying inputs:
         */
        unsigned total_in;

        /* For frag shaders, the total number of inputs (not scalar,
         * ie. SP_VS_PARAM_REG.TOTALVSOUTVAR)
         */
        unsigned varying_in;

        /* Remapping table to map Image and SSBO to hw state: */
        struct ir3_ibo_mapping image_mapping;

        /* number of samplers/textures (which are currently 1:1): */
        int num_samp;

        /* is there an implicit sampler to read framebuffer (FS only).. if
         * so the sampler-idx is 'num_samp - 1' (ie. it is appended after
         * the last "real" texture)
         */
        bool fb_read;

        /* do we have one or more SSBO instructions: */
        bool has_ssbo;

        /* Which bindless resources are used, for filling out sp_xs_config */
        bool bindless_tex;
        bool bindless_samp;
        bool bindless_ibo;
        bool bindless_ubo;

        /* do we need derivatives: */
        bool need_pixlod;

        bool need_fine_derivatives;

        /* do we have image write, etc (which prevents early-z): */
        bool no_earlyz;

        /* do we have kill, which also prevents early-z, but not necessarily
         * early-lrz (as long as lrz-write is disabled, which must be handled
         * outside of ir3.  Unlike other no_earlyz cases, kill doesn't have
         * side effects that prevent early-lrz discard.
         */
        bool has_kill;

        bool per_samp;

        /* Are we using split or merged register file? */
        bool mergedregs;

        /* for astc srgb workaround, the number/base of additional
         * alpha tex states we need, and index of original tex states
         */
        struct {
                unsigned base, count;
                unsigned orig_idx[16];
        } astc_srgb;

        /* shader variants form a linked list: */
        struct ir3_shader_variant *next;

        /* replicated here to avoid passing extra ptrs everywhere: */
        gl_shader_stage type;
        struct ir3_shader *shader;

        /* texture sampler pre-dispatches */
        uint32_t num_sampler_prefetch;
        struct ir3_sampler_prefetch sampler_prefetch[IR3_MAX_SAMPLER_PREFETCH];
};

static inline const char *
ir3_shader_stage(struct ir3_shader_variant *v)
{
        switch (v->type) {
        case MESA_SHADER_VERTEX:     return v->binning_pass ? "BVERT" : "VERT";
        case MESA_SHADER_TESS_CTRL:  return "TCS";
        case MESA_SHADER_TESS_EVAL:  return "TES";
        case MESA_SHADER_GEOMETRY:   return "GEOM";
        case MESA_SHADER_FRAGMENT:   return "FRAG";
        case MESA_SHADER_COMPUTE:    return "CL";
        default:
                unreachable("invalid type");
                return NULL;
        }
}


struct ir3_shader {
        gl_shader_stage type;

        /* shader id (for debug): */
        uint32_t id;
        uint32_t variant_count;

        /* Set by freedreno after shader_state_create, so we can emit debug info
         * when recompiling a shader at draw time.
         */
        bool initial_variants_done;

        struct ir3_compiler *compiler;

        unsigned num_reserved_user_consts;

        struct nir_shader *nir;
        struct ir3_stream_output_info stream_output;

        struct ir3_shader_variant *variants;
        mtx_t variants_lock;

        /* Bitmask of bits of the shader key used by this shader.  Used to avoid
         * recompiles for GL NOS that doesn't actually apply to the shader.
         */
        struct ir3_shader_key key_mask;
};

/**
 * In order to use the same cmdstream, in particular constlen setup and const
 * emit, for both binning and draw pass (a6xx+), the binning pass re-uses it's
 * corresponding draw pass shaders const_state.
 */
static inline struct ir3_const_state *
ir3_const_state(const struct ir3_shader_variant *v)
{
        if (v->binning_pass)
                return v->nonbinning->const_state;
        return v->const_state;
}

/* Given a variant, calculate the maximum constlen it can have.
 */

static inline unsigned
ir3_max_const(const struct ir3_shader_variant *v)
{
        const struct ir3_compiler *compiler = v->shader->compiler;

        if (v->shader->type == MESA_SHADER_COMPUTE) {
                return compiler->max_const_compute;
        } else if (v->key.safe_constlen) {
                return compiler->max_const_safe;
        } else if (v->shader->type == MESA_SHADER_FRAGMENT) {
                return compiler->max_const_frag;
        } else {
                return compiler->max_const_geom;
        }
}

void * ir3_shader_assemble(struct ir3_shader_variant *v);
struct ir3_shader_variant * ir3_shader_get_variant(struct ir3_shader *shader,
                const struct ir3_shader_key *key, bool binning_pass, bool *created);
struct ir3_shader * ir3_shader_from_nir(struct ir3_compiler *compiler, nir_shader *nir,
                unsigned reserved_user_consts, struct ir3_stream_output_info *stream_output);
void ir3_shader_destroy(struct ir3_shader *shader);
void ir3_shader_disasm(struct ir3_shader_variant *so, uint32_t *bin, FILE *out);
uint64_t ir3_shader_outputs(const struct ir3_shader *so);

int
ir3_glsl_type_size(const struct glsl_type *type, bool bindless);

/*
 * Helper/util:
 */

/* clears shader-key flags which don't apply to the given shader.
 */
static inline void
ir3_key_clear_unused(struct ir3_shader_key *key, struct ir3_shader *shader)
{
        uint32_t *key_bits = (uint32_t *)key;
        uint32_t *key_mask = (uint32_t *)&shader->key_mask;
        STATIC_ASSERT(sizeof(*key) % 4 == 0);
        for (int i = 0; i < sizeof(*key) >> 2; i++)
                key_bits[i] &= key_mask[i];
}

static inline int
ir3_find_output(const struct ir3_shader_variant *so, gl_varying_slot slot)
{
        int j;

        for (j = 0; j < so->outputs_count; j++)
                if (so->outputs[j].slot == slot)
                        return j;

        /* it seems optional to have a OUT.BCOLOR[n] for each OUT.COLOR[n]
         * in the vertex shader.. but the fragment shader doesn't know this
         * so  it will always have both IN.COLOR[n] and IN.BCOLOR[n].  So
         * at link time if there is no matching OUT.BCOLOR[n], we must map
         * OUT.COLOR[n] to IN.BCOLOR[n].  And visa versa if there is only
         * a OUT.BCOLOR[n] but no matching OUT.COLOR[n]
         */
        if (slot == VARYING_SLOT_BFC0) {
                slot = VARYING_SLOT_COL0;
        } else if (slot == VARYING_SLOT_BFC1) {
                slot = VARYING_SLOT_COL1;
        } else if (slot == VARYING_SLOT_COL0) {
                slot = VARYING_SLOT_BFC0;
        } else if (slot == VARYING_SLOT_COL1) {
                slot = VARYING_SLOT_BFC1;
        } else {
                return -1;
        }

        for (j = 0; j < so->outputs_count; j++)
                if (so->outputs[j].slot == slot)
                        return j;

        debug_assert(0);

        return -1;
}

static inline int
ir3_next_varying(const struct ir3_shader_variant *so, int i)
{
        while (++i < so->inputs_count)
                if (so->inputs[i].compmask && so->inputs[i].bary)
                        break;
        return i;
}

struct ir3_shader_linkage {
        /* Maximum location either consumed by the fragment shader or produced by
         * the last geometry stage, i.e. the size required for each vertex in the
         * VPC in DWORD's.
         */
        uint8_t max_loc;

        /* Number of entries in var. */
        uint8_t cnt;

        /* Bitset of locations used, including ones which are only used by the FS.
         */
        uint32_t varmask[4];

        /* Map from VS output to location. */
        struct {
                uint8_t regid;
                uint8_t compmask;
                uint8_t loc;
        } var[32];

        /* location for fixed-function gl_PrimitiveID passthrough */
        uint8_t primid_loc;
};

static inline void
ir3_link_add(struct ir3_shader_linkage *l, uint8_t regid_, uint8_t compmask, uint8_t loc)
{
        for (int j = 0; j < util_last_bit(compmask); j++) {
                uint8_t comploc = loc + j;
                l->varmask[comploc / 32] |= 1 << (comploc % 32);
        }

        l->max_loc = MAX2(l->max_loc, loc + util_last_bit(compmask));

        if (regid_ != regid(63, 0)) {
                int i = l->cnt++;
                debug_assert(i < ARRAY_SIZE(l->var));

                l->var[i].regid    = regid_;
                l->var[i].compmask = compmask;
                l->var[i].loc      = loc;
        }
}

static inline void
ir3_link_shaders(struct ir3_shader_linkage *l,
                const struct ir3_shader_variant *vs,
                const struct ir3_shader_variant *fs,
                bool pack_vs_out)
{
        /* On older platforms, varmask isn't programmed at all, and it appears
         * that the hardware generates a mask of used VPC locations using the VS
         * output map, and hangs if a FS bary instruction references a location
         * not in the list. This means that we need to have a dummy entry in the
         * VS out map for things like gl_PointCoord which aren't written by the
         * VS. Furthermore we can't use r63.x, so just pick a random register to
         * use if there is no VS output.
         */
        const unsigned default_regid = pack_vs_out ? regid(63, 0) : regid(0, 0);
        int j = -1, k;

        l->primid_loc = 0xff;

        while (l->cnt < ARRAY_SIZE(l->var)) {
                j = ir3_next_varying(fs, j);

                if (j >= fs->inputs_count)
                        break;

                if (fs->inputs[j].inloc >= fs->total_in)
                        continue;

                k = ir3_find_output(vs, fs->inputs[j].slot);

                if (k < 0 && fs->inputs[j].slot == VARYING_SLOT_PRIMITIVE_ID) {
                        l->primid_loc = fs->inputs[j].inloc;
                }

                ir3_link_add(l, k >= 0 ? vs->outputs[k].regid : default_regid,
                        fs->inputs[j].compmask, fs->inputs[j].inloc);
        }
}

static inline uint32_t
ir3_find_output_regid(const struct ir3_shader_variant *so, unsigned slot)
{
        int j;
        for (j = 0; j < so->outputs_count; j++)
                if (so->outputs[j].slot == slot) {
                        uint32_t regid = so->outputs[j].regid;
                        if (so->outputs[j].half)
                                regid |= HALF_REG_ID;
                        return regid;
                }
        return regid(63, 0);
}

#define VARYING_SLOT_GS_HEADER_IR3                      (VARYING_SLOT_MAX + 0)
#define VARYING_SLOT_GS_VERTEX_FLAGS_IR3        (VARYING_SLOT_MAX + 1)
#define VARYING_SLOT_TCS_HEADER_IR3                     (VARYING_SLOT_MAX + 2)


static inline uint32_t
ir3_find_sysval_regid(const struct ir3_shader_variant *so, unsigned slot)
{
        int j;
        for (j = 0; j < so->inputs_count; j++)
                if (so->inputs[j].sysval && (so->inputs[j].slot == slot))
                        return so->inputs[j].regid;
        return regid(63, 0);
}

/* calculate register footprint in terms of half-regs (ie. one full
 * reg counts as two half-regs).
 */
static inline uint32_t
ir3_shader_halfregs(const struct ir3_shader_variant *v)
{
        return (2 * (v->info.max_reg + 1)) + (v->info.max_half_reg + 1);
}

static inline uint32_t
ir3_shader_nibo(const struct ir3_shader_variant *v)
{
        /* The dummy variant used in binning mode won't have an actual shader. */
        if (!v->shader)
                return 0;

        return v->shader->nir->info.num_ssbos + v->shader->nir->info.num_images;
}

#endif /* IR3_SHADER_H_ */