slang_emit.c

Mesa is an open-source implementation of the OpenGL specification - a system for rendering interacti

static struct prog_instruction *
emit_swizzle(slang_emit_info *emitInfo, slang_ir_node *n)
{
   struct prog_instruction *inst;

   inst = emit(emitInfo, n->Children[0]);

   /* setup storage info, if needed */
   if (!n->Store->Parent)
      n->Store->Parent = n->Children[0]->Store;

   assert(n->Store->Parent);

   return inst;
}


/**
 * Dereference array element.  Just resolve storage for the array
 * element represented by this node.
 */
static struct prog_instruction *
emit_array_element(slang_emit_info *emitInfo, slang_ir_node *n)
{
   slang_ir_storage *root;

   assert(n->Opcode == IR_ELEMENT);
   assert(n->Store);
   assert(n->Store->File == PROGRAM_UNDEFINED);
   assert(n->Store->Parent);
   assert(n->Store->Size > 0);

   root = n->Store;
   while (root->Parent)
      root = root->Parent;

   if (root->File == PROGRAM_STATE_VAR) {
      GLint index = _slang_alloc_statevar(n, emitInfo->prog->Parameters);
      assert(n->Store->Index == index);
      return NULL;
   }

   /* do codegen for array */
   emit(emitInfo, n->Children[0]);

   if (n->Children[1]->Opcode == IR_FLOAT) {
      /* Constant array index.
       * Set Store's index to be the offset of the array element in
       * the register file.
       */
      const GLint element = (GLint) n->Children[1]->Value[0];
      const GLint sz = (n->Store->Size + 3) / 4; /* size in slots/registers */

      n->Store->Index = sz * element;
      assert(n->Store->Parent);
   }
   else {
      /* Variable array index */
      struct prog_instruction *inst;

      /* do codegen for array index expression */
      emit(emitInfo, n->Children[1]);

      inst = new_instruction(emitInfo, OPCODE_ARL);

      storage_to_dst_reg(&inst->DstReg, n->Store, n->Writemask);
      storage_to_src_reg(&inst->SrcReg[0], n->Children[1]->Store);

      inst->DstReg.File = PROGRAM_ADDRESS;
      inst->DstReg.Index = 0; /* always address register [0] */
      inst->Comment = _mesa_strdup("ARL ADDR");

      n->Store->RelAddr = GL_TRUE;
   }

   /* if array element size is one, make sure we only access X */
   if (n->Store->Size == 1)
      n->Store->Swizzle = SWIZZLE_XXXX;

   return NULL; /* no instruction */
}


/**
 * Resolve storage for accessing a structure field.
 */
static struct prog_instruction *
emit_struct_field(slang_emit_info *emitInfo, slang_ir_node *n)
{
   slang_ir_storage *root = n->Store;

   assert(n->Opcode == IR_FIELD);

   while (root->Parent)
      root = root->Parent;

   /* If this is the field of a state var, allocate constant/uniform
    * storage for it now if we haven't already.
    * Note that we allocate storage (uniform/constant slots) for state
    * variables here rather than at declaration time so we only allocate
    * space for the ones that we actually use!
    */
   if (root->File == PROGRAM_STATE_VAR) {
      root->Index = _slang_alloc_statevar(n, emitInfo->prog->Parameters);
      if (root->Index < 0) {
         slang_info_log_error(emitInfo->log, "Error parsing state variable");
         return NULL;
      }
   }
   else {
      /* do codegen for struct */
      emit(emitInfo, n->Children[0]);
   }

   return NULL; /* no instruction */
}


/**
 * Emit code for a variable declaration.
 * This usually doesn't result in any code generation, but just
 * memory allocation.
 */
static struct prog_instruction *
emit_var_decl(slang_emit_info *emitInfo, slang_ir_node *n)
{
   struct prog_instruction *inst;

   assert(n->Store);
   assert(n->Store->File != PROGRAM_UNDEFINED);
   assert(n->Store->Size > 0);
   /*assert(n->Store->Index < 0);*/

   if (!n->Var || n->Var->isTemp) {
      /* a nameless/temporary variable, will be freed after first use */
      /*NEW*/
      if (n->Store->Index < 0 && !_slang_alloc_temp(emitInfo->vt, n->Store)) {
         slang_info_log_error(emitInfo->log,
                              "Ran out of registers, too many temporaries");
         return NULL;
      }
   }
   else {
      /* a regular variable */
      _slang_add_variable(emitInfo->vt, n->Var);
      if (!_slang_alloc_var(emitInfo->vt, n->Store)) {
         slang_info_log_error(emitInfo->log,
                              "Ran out of registers, too many variables");
         return NULL;
      }
      /*
        printf("IR_VAR_DECL %s %d store %p\n",
        (char*) n->Var->a_name, n->Store->Index, (void*) n->Store);
      */
      assert(n->Var->aux == n->Store);
   }
   if (emitInfo->EmitComments) {
      /* emit NOP with comment describing the variable's storage location */
      char s[1000];
      sprintf(s, "TEMP[%d]%s = variable %s (size %d)",
              n->Store->Index,
              _mesa_swizzle_string(n->Store->Swizzle, 0, GL_FALSE), 
              (n->Var ? (char *) n->Var->a_name : "anonymous"),
              n->Store->Size);
      inst = emit_comment(emitInfo, s);
      return inst;
   }
   return NULL;
}


/**
 * Emit code for a reference to a variable.
 * Actually, no code is generated but we may do some memory alloation.
 * In particular, state vars (uniforms) are allocated on an as-needed basis.
 */
static struct prog_instruction *
emit_var_ref(slang_emit_info *emitInfo, slang_ir_node *n)
{
   assert(n->Store);
   assert(n->Store->File != PROGRAM_UNDEFINED);

   if (n->Store->File == PROGRAM_STATE_VAR && n->Store->Index < 0) {
      n->Store->Index = _slang_alloc_statevar(n, emitInfo->prog->Parameters);
   }
   else if (n->Store->File == PROGRAM_UNIFORM) {
      /* mark var as used */
      _mesa_use_uniform(emitInfo->prog->Parameters, (char *) n->Var->a_name);
   }

   if (n->Store->Index < 0) {
      /* probably ran out of registers */
      return NULL;
   }
   assert(n->Store->Size > 0);

   return NULL;
}


static struct prog_instruction *
emit(slang_emit_info *emitInfo, slang_ir_node *n)
{
   struct prog_instruction *inst;
   if (!n)
      return NULL;

   if (emitInfo->log->error_flag) {
      return NULL;
   }

   switch (n->Opcode) {
   case IR_SEQ:
      /* sequence of two sub-trees */
      assert(n->Children[0]);
      assert(n->Children[1]);
      emit(emitInfo, n->Children[0]);
      if (emitInfo->log->error_flag)
         return NULL;
      inst = emit(emitInfo, n->Children[1]);
#if 0
      assert(!n->Store);
#endif
      n->Store = n->Children[1]->Store;
      return inst;

   case IR_SCOPE:
      /* new variable scope */
      _slang_push_var_table(emitInfo->vt);
      inst = emit(emitInfo, n->Children[0]);
      _slang_pop_var_table(emitInfo->vt);
      return inst;

   case IR_VAR_DECL:
      /* Variable declaration - allocate a register for it */
      inst = emit_var_decl(emitInfo, n);
      return inst;

   case IR_VAR:
      /* Reference to a variable
       * Storage should have already been resolved/allocated.
       */
      return emit_var_ref(emitInfo, n);

   case IR_ELEMENT:
      return emit_array_element(emitInfo, n);
   case IR_FIELD:
      return emit_struct_field(emitInfo, n);
   case IR_SWIZZLE:
      return emit_swizzle(emitInfo, n);

   /* Simple arithmetic */
   /* unary */
   case IR_MOVE:
   case IR_RSQ:
   case IR_RCP:
   case IR_FLOOR:
   case IR_FRAC:
   case IR_F_TO_I:
   case IR_I_TO_F:
   case IR_ABS:
   case IR_SIN:
   case IR_COS:
   case IR_DDX:
   case IR_DDY:
   case IR_EXP:
   case IR_EXP2:
   case IR_LOG2:
   case IR_NOISE1:
   case IR_NOISE2:
   case IR_NOISE3:
   case IR_NOISE4:
   /* binary */
   case IR_ADD:
   case IR_SUB:
   case IR_MUL:
   case IR_DOT4:
   case IR_DOT3:
   case IR_CROSS:
   case IR_MIN:
   case IR_MAX:
   case IR_SEQUAL:
   case IR_SNEQUAL:
   case IR_SGE:
   case IR_SGT:
   case IR_SLE:
   case IR_SLT:
   case IR_POW:
   /* trinary operators */
   case IR_LRP:
      return emit_arith(emitInfo, n);

   case IR_EQUAL:
   case IR_NOTEQUAL:
      return emit_compare(emitInfo, n);

   case IR_CLAMP:
      return emit_clamp(emitInfo, n);
   case IR_TEX:
   case IR_TEXB:
   case IR_TEXP:
      return emit_tex(emitInfo, n);
   case IR_NEG:
      return emit_negation(emitInfo, n);
   case IR_FLOAT:
      /* find storage location for this float constant */
      n->Store->Index = _mesa_add_unnamed_constant(emitInfo->prog->Parameters,
                                                   n->Value,
                                                   n->Store->Size,
                                                   &n->Store->Swizzle);
      if (n->Store->Index < 0) {
         slang_info_log_error(emitInfo->log, "Ran out of space for constants");
         return NULL;
      }
      return NULL;

   case IR_COPY:
      return emit_copy(emitInfo, n);

   case IR_COND:
      return emit_cond(emitInfo, n);

   case IR_NOT:
      return emit_not(emitInfo, n);

   case IR_LABEL:
      return emit_label(emitInfo, n);

   case IR_KILL:
      return emit_kill(emitInfo);

   case IR_CALL:
      /* new variable scope for subroutines/function calls */
      _slang_push_var_table(emitInfo->vt);
      inst = emit_fcall(emitInfo, n);
      _slang_pop_var_table(emitInfo->vt);
      return inst;

   case IR_IF:
      return emit_if(emitInfo, n);

   case IR_LOOP:
      return emit_loop(emitInfo, n);
   case IR_BREAK_IF_TRUE:
   case IR_CONT_IF_TRUE:
      return emit_cont_break_if_true(emitInfo, n);
   case IR_BREAK:
      /* fall-through */
   case IR_CONT:
      return emit_cont_break(emitInfo, n);

   case IR_BEGIN_SUB:
      return new_instruction(emitInfo, OPCODE_BGNSUB);
   case IR_END_SUB:
      return new_instruction(emitInfo, OPCODE_ENDSUB);
   case IR_RETURN:
      return emit_return(emitInfo, n);

   case IR_NOP:
      return NULL;

   default:
      _mesa_problem(NULL, "Unexpected IR opcode in emit()\n");
   }
   return NULL;
}


/**
 * After code generation, any subroutines will be in separate program
 * objects.  This function appends all the subroutines onto the main
 * program and resolves the linking of all the branch/call instructions.
 * XXX this logic should really be part of the linking process...
 */
static void
_slang_resolve_subroutines(slang_emit_info *emitInfo)
{
   GET_CURRENT_CONTEXT(ctx);
   struct gl_program *mainP = emitInfo->prog;
   GLuint *subroutineLoc, i, total;

   subroutineLoc
      = (GLuint *) _mesa_malloc(emitInfo->NumSubroutines * sizeof(GLuint));

   /* total number of instructions */
   total = mainP->NumInstructions;
   for (i = 0; i < emitInfo->NumSubroutines; i++) {
      subroutineLoc[i] = total;
      total += emitInfo->Subroutines[i]->NumInstructions;
   }

   /* adjust BrancTargets within the functions */
   for (i = 0; i < emitInfo->NumSubroutines; i++) {
      struct gl_program *sub = emitInfo->Subroutines[i];
      GLuint j;
      for (j = 0; j < sub->NumInstructions; j++) {
         struct prog_instruction *inst = sub->Instructions + j;
         if (inst->Opcode != OPCODE_CAL && inst->BranchTarget >= 0) {
            inst->BranchTarget += subroutineLoc[i];
         }
      }
   }

   /* append subroutines' instructions after main's instructions */
   mainP->Instructions = _mesa_realloc_instructions(mainP->Instructions,
                                                    mainP->NumInstructions,
                                                    total);
   mainP->NumInstructions = total;
   for (i = 0; i < emitInfo->NumSubroutines; i++) {
      struct gl_program *sub = emitInfo->Subroutines[i];
      _mesa_copy_instructions(mainP->Instructions + subroutineLoc[i],
                              sub->Instructions,
                              sub->NumInstructions);
      /* delete subroutine code */
      sub->Parameters = NULL; /* prevent double-free */
      _mesa_reference_program(ctx, &emitInfo->Subroutines[i], NULL);
   }

   /* free subroutine list */
   if (emitInfo->Subroutines) {
      _mesa_free(emitInfo->Subroutines);
      emitInfo->Subroutines = NULL;
   }
   emitInfo->NumSubroutines = 0;

   /* Examine CAL instructions.
    * At this point, the BranchTarget field of the CAL instruction is
    * the number/id of the subroutine to call (an index into the
    * emitInfo->Subroutines list).
    * Translate that into an actual instruction location now.
    */
   for (i = 0; i < mainP->NumInstructions; i++) {
      struct prog_instruction *inst = mainP->Instructions + i;
      if (inst->Opcode == OPCODE_CAL) {
         const GLuint f = inst->BranchTarget;
         inst->BranchTarget = subroutineLoc[f];
      }
   }

   _mesa_free(subroutineLoc);
}




GLboolean
_slang_emit_code(slang_ir_node *n, slang_var_table *vt,
                 struct gl_program *prog, GLboolean withEnd,
                 slang_info_log *log)
{
   GET_CURRENT_CONTEXT(ctx);
   GLboolean success;
   slang_emit_info emitInfo;
   GLuint maxUniforms;

   emitInfo.log = log;
   emitInfo.vt = vt;
   emitInfo.prog = prog;
   emitInfo.Subroutines = NULL;
   emitInfo.NumSubroutines = 0;

   emitInfo.EmitHighLevelInstructions = ctx->Shader.EmitHighLevelInstructions;
   emitInfo.EmitCondCodes = ctx->Shader.EmitCondCodes;
   emitInfo.EmitComments = ctx->Shader.EmitComments;
   emitInfo.EmitBeginEndSub = GL_TRUE;

   if (!emitInfo.EmitCondCodes) {
      emitInfo.EmitHighLevelInstructions = GL_TRUE;
   }      

   /* Check uniform/constant limits */
   if (prog->Target == GL_FRAGMENT_PROGRAM_ARB) {
      maxUniforms = ctx->Const.FragmentProgram.MaxUniformComponents / 4;
   }
   else {
      assert(prog->Target == GL_VERTEX_PROGRAM_ARB);
      maxUniforms = ctx->Const.VertexProgram.MaxUniformComponents / 4;
   }
   if (prog->Parameters->NumParameters > maxUniforms) {
      slang_info_log_error(log, "Constant/uniform register limit exceeded");
      return GL_FALSE;
   }

   (void) emit(&emitInfo, n);

   /* finish up by adding the END opcode to program */
   if (withEnd) {
      struct prog_instruction *inst;
      inst = new_instruction(&emitInfo, OPCODE_END);
   }

   _slang_resolve_subroutines(&emitInfo);

   success = GL_TRUE;

#if 0
   printf("*********** End emit code (%u inst):\n", prog->NumInstructions);
   _mesa_print_program(prog);
   _mesa_print_program_parameters(ctx,prog);
#endif

   return success;
}