slang_codegen.c

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

                       substCount, substOld, substNew, GL_TRUE);
      slang_substitute(A, &oper->children[1],
                       substCount, substOld, substNew, GL_FALSE);
      break;
   case SLANG_OPER_FIELD:
      /* XXX NEW - test */
      slang_substitute(A, &oper->children[0],
                       substCount, substOld, substNew, GL_TRUE);
      break;
   default:
      {
         GLuint i;
         for (i = 0; i < oper->num_children; i++) 
            slang_substitute(A, &oper->children[i],
                             substCount, substOld, substNew, GL_FALSE);
      }
   }
}


/**
 * Produce inline code for a call to an assembly instruction.
 * This is typically used to compile a call to a built-in function like this:
 *
 * vec4 mix(const vec4 x, const vec4 y, const vec4 a)
 * {
 *    __asm vec4_lrp __retVal, a, y, x;
 * }
 *
 *
 * A call to
 *     r = mix(p1, p2, p3);
 *
 * Becomes:
 *
 *              mov
 *             /   \
 *            r   vec4_lrp
 *                 /  |  \
 *                p3  p2  p1
 *
 * We basically translate a SLANG_OPER_CALL into a SLANG_OPER_ASM.
 */
static slang_operation *
slang_inline_asm_function(slang_assemble_ctx *A,
                          slang_function *fun, slang_operation *oper)
{
   const GLuint numArgs = oper->num_children;
   GLuint i;
   slang_operation *inlined;
   const GLboolean haveRetValue = _slang_function_has_return_value(fun);
   slang_variable **substOld;
   slang_operation **substNew;

   ASSERT(slang_is_asm_function(fun));
   ASSERT(fun->param_count == numArgs + haveRetValue);

   /*
   printf("Inline %s as %s\n",
          (char*) fun->header.a_name,
          (char*) fun->body->children[0].a_id);
   */

   /*
    * We'll substitute formal params with actual args in the asm call.
    */
   substOld = (slang_variable **)
      _slang_alloc(numArgs * sizeof(slang_variable *));
   substNew = (slang_operation **)
      _slang_alloc(numArgs * sizeof(slang_operation *));
   for (i = 0; i < numArgs; i++) {
      substOld[i] = fun->parameters->variables[i];
      substNew[i] = oper->children + i;
   }

   /* make a copy of the code to inline */
   inlined = slang_operation_new(1);
   slang_operation_copy(inlined, &fun->body->children[0]);
   if (haveRetValue) {
      /* get rid of the __retVal child */
      inlined->num_children--;
      for (i = 0; i < inlined->num_children; i++) {
         inlined->children[i] = inlined->children[i + 1];
      }
   }

   /* now do formal->actual substitutions */
   slang_substitute(A, inlined, numArgs, substOld, substNew, GL_FALSE);

   _slang_free(substOld);
   _slang_free(substNew);

#if 0
   printf("+++++++++++++ inlined asm function %s +++++++++++++\n",
          (char *) fun->header.a_name);
   slang_print_tree(inlined, 3);
   printf("+++++++++++++++++++++++++++++++++++++++++++++++++++\n");
#endif

   return inlined;
}


/**
 * Inline the given function call operation.
 * Return a new slang_operation that corresponds to the inlined code.
 */
static slang_operation *
slang_inline_function_call(slang_assemble_ctx * A, slang_function *fun,
			   slang_operation *oper, slang_operation *returnOper)
{
   typedef enum {
      SUBST = 1,
      COPY_IN,
      COPY_OUT
   } ParamMode;
   ParamMode *paramMode;
   const GLboolean haveRetValue = _slang_function_has_return_value(fun);
   const GLuint numArgs = oper->num_children;
   const GLuint totalArgs = numArgs + haveRetValue;
   slang_operation *args = oper->children;
   slang_operation *inlined, *top;
   slang_variable **substOld;
   slang_operation **substNew;
   GLuint substCount, numCopyIn, i;
   slang_function *prevFunction;
   slang_variable_scope *newScope = NULL;

   /* save / push */
   prevFunction = A->CurFunction;
   A->CurFunction = fun;

   /*assert(oper->type == SLANG_OPER_CALL); (or (matrix) multiply, etc) */
   assert(fun->param_count == totalArgs);

   /* allocate temporary arrays */
   paramMode = (ParamMode *)
      _slang_alloc(totalArgs * sizeof(ParamMode));
   substOld = (slang_variable **)
      _slang_alloc(totalArgs * sizeof(slang_variable *));
   substNew = (slang_operation **)
      _slang_alloc(totalArgs * sizeof(slang_operation *));

#if 0
   printf("\nInline call to %s  (total vars=%d  nparams=%d)\n",
	  (char *) fun->header.a_name,
	  fun->parameters->num_variables, numArgs);
#endif

   if (haveRetValue && !returnOper) {
      /* Create 3-child comma sequence for inlined code:
       * child[0]:  declare __resultTmp
       * child[1]:  inlined function body
       * child[2]:  __resultTmp
       */
      slang_operation *commaSeq;
      slang_operation *declOper = NULL;
      slang_variable *resultVar;

      commaSeq = slang_operation_new(1);
      commaSeq->type = SLANG_OPER_SEQUENCE;
      assert(commaSeq->locals);
      commaSeq->locals->outer_scope = oper->locals->outer_scope;
      commaSeq->num_children = 3;
      commaSeq->children = slang_operation_new(3);
      /* allocate the return var */
      resultVar = slang_variable_scope_grow(commaSeq->locals);
      /*
      printf("Alloc __resultTmp in scope %p for retval of calling %s\n",
             (void*)commaSeq->locals, (char *) fun->header.a_name);
      */

      resultVar->a_name = slang_atom_pool_atom(A->atoms, "__resultTmp");
      resultVar->type = fun->header.type; /* XXX copy? */
      resultVar->isTemp = GL_TRUE;

      /* child[0] = __resultTmp declaration */
      declOper = &commaSeq->children[0];
      declOper->type = SLANG_OPER_VARIABLE_DECL;
      declOper->a_id = resultVar->a_name;
      declOper->locals->outer_scope = commaSeq->locals;

      /* child[1] = function body */
      inlined = &commaSeq->children[1];
      inlined->locals->outer_scope = commaSeq->locals;

      /* child[2] = __resultTmp reference */
      returnOper = &commaSeq->children[2];
      returnOper->type = SLANG_OPER_IDENTIFIER;
      returnOper->a_id = resultVar->a_name;
      returnOper->locals->outer_scope = commaSeq->locals;

      top = commaSeq;
   }
   else {
      top = inlined = slang_operation_new(1);
      /* XXXX this may be inappropriate!!!! */
      inlined->locals->outer_scope = oper->locals->outer_scope;
   }


   assert(inlined->locals);

   /* Examine the parameters, look for inout/out params, look for possible
    * substitutions, etc:
    *    param type      behaviour
    *     in             copy actual to local
    *     const in       substitute param with actual
    *     out            copy out
    */
   substCount = 0;
   for (i = 0; i < totalArgs; i++) {
      slang_variable *p = fun->parameters->variables[i];
      /*
      printf("Param %d: %s %s \n", i,
             slang_type_qual_string(p->type.qualifier),
	     (char *) p->a_name);
      */
      if (p->type.qualifier == SLANG_QUAL_INOUT ||
	  p->type.qualifier == SLANG_QUAL_OUT) {
	 /* an output param */
         slang_operation *arg;
         if (i < numArgs)
            arg = &args[i];
         else
            arg = returnOper;
	 paramMode[i] = SUBST;

	 if (arg->type == SLANG_OPER_IDENTIFIER)
            slang_resolve_variable(arg);

         /* replace parameter 'p' with argument 'arg' */
	 substOld[substCount] = p;
	 substNew[substCount] = arg; /* will get copied */
	 substCount++;
      }
      else if (p->type.qualifier == SLANG_QUAL_CONST) {
	 /* a constant input param */
	 if (args[i].type == SLANG_OPER_IDENTIFIER ||
	     args[i].type == SLANG_OPER_LITERAL_FLOAT) {
	    /* replace all occurances of this parameter variable with the
	     * actual argument variable or a literal.
	     */
	    paramMode[i] = SUBST;
            slang_resolve_variable(&args[i]);
	    substOld[substCount] = p;
	    substNew[substCount] = &args[i]; /* will get copied */
	    substCount++;
	 }
	 else {
	    paramMode[i] = COPY_IN;
	 }
      }
      else {
	 paramMode[i] = COPY_IN;
      }
      assert(paramMode[i]);
   }

   /* actual code inlining: */
   slang_operation_copy(inlined, fun->body);

   /*** XXX review this */
   assert(inlined->type == SLANG_OPER_BLOCK_NO_NEW_SCOPE ||
          inlined->type == SLANG_OPER_BLOCK_NEW_SCOPE);
   inlined->type = SLANG_OPER_BLOCK_NEW_SCOPE;

#if 0
   printf("======================= orig body code ======================\n");
   printf("=== params scope = %p\n", (void*) fun->parameters);
   slang_print_tree(fun->body, 8);
   printf("======================= copied code =========================\n");
   slang_print_tree(inlined, 8);
#endif

   /* do parameter substitution in inlined code: */
   slang_substitute(A, inlined, substCount, substOld, substNew, GL_FALSE);

#if 0
   printf("======================= subst code ==========================\n");
   slang_print_tree(inlined, 8);
   printf("=============================================================\n");
#endif

   /* New prolog statements: (inserted before the inlined code)
    * Copy the 'in' arguments.
    */
   numCopyIn = 0;
   for (i = 0; i < numArgs; i++) {
      if (paramMode[i] == COPY_IN) {
	 slang_variable *p = fun->parameters->variables[i];
	 /* declare parameter 'p' */
	 slang_operation *decl = slang_operation_insert(&inlined->num_children,
							&inlined->children,
							numCopyIn);

	 decl->type = SLANG_OPER_VARIABLE_DECL;
         assert(decl->locals);
         decl->locals->outer_scope = inlined->locals;
	 decl->a_id = p->a_name;
	 decl->num_children = 1;
	 decl->children = slang_operation_new(1);

         /* child[0] is the var's initializer */
         slang_operation_copy(&decl->children[0], args + i);

         /* add parameter 'p' to the local variable scope here */
         {
            slang_variable *pCopy = slang_variable_scope_grow(inlined->locals);
            pCopy->type = p->type;
            pCopy->a_name = p->a_name;
            pCopy->array_len = p->array_len;
         }

         newScope = inlined->locals;
	 numCopyIn++;
      }
   }

   /* Now add copies of the function's local vars to the new variable scope */
   for (i = totalArgs; i < fun->parameters->num_variables; i++) {
      slang_variable *p = fun->parameters->variables[i];
      slang_variable *pCopy = slang_variable_scope_grow(inlined->locals);
      pCopy->type = p->type;
      pCopy->a_name = p->a_name;
      pCopy->array_len = p->array_len;
   }


   /* New epilog statements:
    * 1. Create end of function label to jump to from return statements.
    * 2. Copy the 'out' parameter vars
    */
   {
      slang_operation *lab = slang_operation_insert(&inlined->num_children,
                                                    &inlined->children,
                                                    inlined->num_children);
      lab->type = SLANG_OPER_LABEL;
      lab->label = A->curFuncEndLabel;
   }

   for (i = 0; i < totalArgs; i++) {
      if (paramMode[i] == COPY_OUT) {
	 const slang_variable *p = fun->parameters->variables[i];
	 /* actualCallVar = outParam */
	 /*if (i > 0 || !haveRetValue)*/
	 slang_operation *ass = slang_operation_insert(&inlined->num_children,
						       &inlined->children,
						       inlined->num_children);
	 ass->type = SLANG_OPER_ASSIGN;
	 ass->num_children = 2;
         ass->locals->outer_scope = inlined->locals;
	 ass->children = slang_operation_new(2);
	 ass->children[0] = args[i]; /*XXX copy */
	 ass->children[1].type = SLANG_OPER_IDENTIFIER;
	 ass->children[1].a_id = p->a_name;
         ass->children[1].locals->outer_scope = ass->locals;
      }
   }

   _slang_free(paramMode);
   _slang_free(substOld);
   _slang_free(substNew);

   /* Update scoping to use the new local vars instead of the
    * original function's vars.  This is especially important
    * for nested inlining.
    */
   if (newScope)
      slang_replace_scope(inlined, fun->parameters, newScope);

#if 0
   printf("Done Inline call to %s  (total vars=%d  nparams=%d)\n\n",
	  (char *) fun->header.a_name,
	  fun->parameters->num_variables, numArgs);
   slang_print_tree(top, 0);
#endif

   /* pop */
   A->CurFunction = prevFunction;

   return top;
}


static slang_ir_node *
_slang_gen_function_call(slang_assemble_ctx *A, slang_function *fun,
                         slang_operation *oper, slang_operation *dest)
{
   slang_ir_node *n;
   slang_operation *inlined;
   slang_label *prevFuncEndLabel;
   char name[200];

   prevFuncEndLabel = A->curFuncEndLabel;
   sprintf(name, "__endOfFunc_%s_", (char *) fun->header.a_name);
   A->curFuncEndLabel = _slang_label_new(name);
   assert(A->curFuncEndLabel);

   if (slang_is_asm_function(fun) && !dest) {
      /* assemble assembly function - tree style */
      inlined = slang_inline_asm_function(A, fun, oper);
   }
   else {
      /* non-assembly function */
      /* We always generate an "inline-able" block of code here.
       * We may either:
       *  1. insert the inline code
       *  2. Generate a call to the "inline" code as a subroutine
       */


      slang_operation *ret = NULL;

      inlined = slang_inline_function_call(A, fun, oper, dest);
      if (!inlined)
         return NULL;

      ret = _slang_find_node_type(inlined, SLANG_OPER_RETURN);
      if (ret) {
         /* check if this is a "tail" return */
         if (_slang_count_node_type(inlined, SLANG_OPER_RETURN) == 1 &&
             _slang_is_tail_return(inlined)) {
            /* The only RETURN is the last stmt in the function, no-op it
             * and inline the function body.
             */
            ret->type = SLANG_OPER_NONE;
         }
         else {
            slang_operation *callOper;
            /* The function we're calling has one or more 'return' statements.
             * So, we can't truly inline this function because we need to
             * implement 'return' with RET (and CAL).
             * Nevertheless, we performed "inlining" to make a new instance
             * of the function body to deal with static register allocation.
             *
             * XXX check if there's one 'return' and if it's the very last
             * statement in the function - we can optimize that case.
             */
            assert(inlined->type == SLANG_OPER_BLOCK_NEW_SCOPE ||
                   inlined->type == SLANG_OPER_SEQUENCE);

            if (_slang_function_has_return_value(fun) && !dest) {
               assert(inlined->children[0].type == SLANG_OPER_VARIABLE_DECL);
               assert(inlined->children[2].type == SLANG_OPER_IDENTIFIER);
               callOper = &inlined->children[1];
            }
            else {
               callOper = inlined;
            }
            callOper->type = SLANG_OPER_NON_INLINED_CALL;
            callOper->fun = fun;
            callOper->label = _slang_label_new_unique((char*) fun->header.a_name);
         }
      }
   }

   if (!inlined)
      return NULL;