mesa/src/compiler/nir/nir_lower_printf.c

/*
 * Copyright © 2020 Microsoft Corporation
 *
 * 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.
 */

#include "nir.h"
#include "nir_builder.h"
#include "nir_builder_opcodes.h"

#include "util/u_math.h"

static bool
lower_printf_intrin(nir_builder *b, nir_intrinsic_instr *prntf, void *_options)
{
   const nir_lower_printf_options *options = _options;
   if (prntf->intrinsic != nir_intrinsic_printf)
      return false;

   b->cursor = nir_before_instr(&prntf->instr);

   nir_def *fmt_str_id = prntf->src[0].ssa;
   if (options && options->use_printf_base_identifier) {
      fmt_str_id = nir_iadd(b,
                            nir_load_printf_base_identifier(b),
                            fmt_str_id);
   }

   nir_deref_instr *args = nir_src_as_deref(prntf->src[1]);
   assert(args->deref_type == nir_deref_type_var);

   const unsigned ptr_bit_size = options->ptr_bit_size != 0 ?
      options->ptr_bit_size : nir_get_ptr_bitsize(b->shader);

   /* Atomic add a buffer size counter to determine where to write.  If
    * overflowed, return -1, otherwise, store the arguments and return 0.
    */
   nir_def *buffer_addr = nir_load_printf_buffer_address(b, ptr_bit_size);
   nir_deref_instr *buffer =
      nir_build_deref_cast(b, buffer_addr, nir_var_mem_global,
                           glsl_array_type(glsl_uint8_t_type(), 0, 4), 0);

   /* Align the struct size to 4 */
   assert(glsl_type_is_struct_or_ifc(args->type));
   int args_size = align(glsl_get_cl_size(args->type), 4);
   assert(fmt_str_id->bit_size == 32);
   int fmt_str_id_size = 4;

   /* Increment the counter at the beginning of the buffer */
   const unsigned counter_size = 4;
   nir_deref_instr *counter = nir_build_deref_array_imm(b, buffer, 0);
   counter = nir_build_deref_cast(b, &counter->def,
                                  nir_var_mem_global,
                                  glsl_uint_type(), 0);
   counter->cast.align_mul = 4;
   nir_def *offset =
      nir_deref_atomic(b, 32, &counter->def,
                       nir_imm_int(b, fmt_str_id_size + args_size),
                       .atomic_op = nir_atomic_op_iadd);

   /* Check if we're still in-bounds */
   const unsigned default_buffer_size = 1024 * 1024;
   unsigned buffer_size = (options && options->max_buffer_size) ? options->max_buffer_size : default_buffer_size;
   int max_valid_offset =
      buffer_size - args_size - fmt_str_id_size - counter_size;
   nir_push_if(b, nir_ilt_imm(b, offset, max_valid_offset));

   nir_def *printf_succ_val = nir_imm_int(b, 0);

   /* Write the format string ID */
   nir_def *fmt_str_id_offset =
      nir_i2iN(b, offset, ptr_bit_size);
   nir_deref_instr *fmt_str_id_deref =
      nir_build_deref_array(b, buffer, fmt_str_id_offset);
   fmt_str_id_deref = nir_build_deref_cast(b, &fmt_str_id_deref->def,
                                           nir_var_mem_global,
                                           glsl_uint_type(), 0);
   fmt_str_id_deref->cast.align_mul = 4;
   nir_store_deref(b, fmt_str_id_deref, fmt_str_id, ~0);

   /* Write the format args */
   for (unsigned i = 0; i < glsl_get_length(args->type); ++i) {
      nir_deref_instr *arg_deref = nir_build_deref_struct(b, args, i);
      nir_def *arg = nir_load_deref(b, arg_deref);
      const struct glsl_type *arg_type = arg_deref->type;

      unsigned field_offset = glsl_get_struct_field_offset(args->type, i);
      nir_def *arg_offset =
         nir_i2iN(b, nir_iadd_imm(b, offset, fmt_str_id_size + field_offset),
                  ptr_bit_size);
      nir_deref_instr *dst_arg_deref =
         nir_build_deref_array(b, buffer, arg_offset);
      dst_arg_deref = nir_build_deref_cast(b, &dst_arg_deref->def,
                                           nir_var_mem_global, arg_type, 0);
      assert(field_offset % 4 == 0);
      dst_arg_deref->cast.align_mul = 4;
      nir_store_deref(b, dst_arg_deref, arg, ~0);
   }

   nir_push_else(b, NULL);
   nir_def *printf_fail_val = nir_imm_int(b, -1);
   nir_pop_if(b, NULL);

   nir_def *ret_val = nir_if_phi(b, printf_succ_val, printf_fail_val);
   nir_def_rewrite_uses(&prntf->def, ret_val);
   nir_instr_remove(&prntf->instr);

   return true;
}

bool
nir_lower_printf(nir_shader *nir, const nir_lower_printf_options *options)
{
   return nir_shader_intrinsics_pass(nir, lower_printf_intrin,
                                     nir_metadata_none,
                                     (void *)options);
}

void
nir_printf_fmt(nir_builder *b,
               bool use_printf_base_identifier,
               unsigned ptr_bit_size,
               const char *fmt, ...)
{
   b->shader->printf_info_count++;
   b->shader->printf_info = reralloc(b->shader,
                                     b->shader->printf_info,
                                     u_printf_info,
                                     b->shader->printf_info_count);

   u_printf_info *info =
      &b->shader->printf_info[b->shader->printf_info_count - 1];

   *info = (u_printf_info) {
      .strings = ralloc_strdup(b->shader, fmt),
      .string_size = strlen(fmt) + 1,
   };

   va_list ap;
   size_t pos = 0;
   size_t args_size = 0;

   va_start(ap, fmt);
   while ((pos = util_printf_next_spec_pos(fmt, pos)) != -1) {
      unsigned arg_size;
      switch (fmt[pos]) {
      case 'c': arg_size = 1; break;
      case 'd': arg_size = 4; break;
      case 'e': arg_size = 4; break;
      case 'E': arg_size = 4; break;
      case 'f': arg_size = 4; break;
      case 'F': arg_size = 4; break;
      case 'G': arg_size = 4; break;
      case 'a': arg_size = 4; break;
      case 'A': arg_size = 4; break;
      case 'i': arg_size = 4; break;
      case 'u': arg_size = 4; break;
      case 'x': arg_size = 4; break;
      case 'X': arg_size = 4; break;
      case 'p': arg_size = 8; break;
      default:  unreachable("invalid");
      }

      ASSERTED nir_def *def = va_arg(ap, nir_def*);
      assert(def->bit_size / 8 == arg_size);

      info->num_args++;
      info->arg_sizes = reralloc(b->shader,
                                 info->arg_sizes,
                                 unsigned, info->num_args);
      info->arg_sizes[info->num_args - 1] = arg_size;

      args_size += arg_size;
   }
   va_end(ap);

   nir_def *buffer_addr =
      nir_load_printf_buffer_address(
         b, ptr_bit_size ? ptr_bit_size : nir_get_ptr_bitsize(b->shader));
   nir_def *buffer_offset =
      nir_global_atomic(b, 32, buffer_addr,
                        nir_imm_int(b, args_size + sizeof(uint32_t)),
                        .atomic_op = nir_atomic_op_iadd);

   /* Identifier */
   nir_def *identifier =
      use_printf_base_identifier ?
      nir_iadd_imm(b,
                   nir_load_printf_base_identifier(b),
                   b->shader->printf_info_count) :
      nir_imm_int(b, b->shader->printf_info_count);

   nir_def *store_addr =
      nir_iadd(b, buffer_addr, nir_i2iN(b, buffer_offset,
                                           buffer_addr->bit_size));
   nir_store_global(b, store_addr, 4, identifier, 0x1);

   /* Arguments */
   va_start(ap, fmt);
   unsigned store_offset = sizeof(uint32_t);
   for (unsigned a = 0; a < info->num_args; a++) {
      nir_def *def = va_arg(ap, nir_def*);

      nir_store_global(b, nir_iadd_imm(b, store_addr, store_offset),
                       4, def, 0x1);

      store_offset += info->arg_sizes[a];
   }
   va_end(ap);
}