slang_emit.c

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

/*
 * Mesa 3-D graphics library
 * Version:  7.1
 *
 * Copyright (C) 2005-2008  Brian Paul   All Rights Reserved.
 *
 * 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 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
 * BRIAN PAUL 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.
 */

/**
 * \file slang_emit.c
 * Emit program instructions (PI code) from IR trees.
 * \author Brian Paul
 */

/***
 *** NOTES
 ***
 *** To emit GPU instructions, we basically just do an in-order traversal
 *** of the IR tree.
 ***/


#include "main/imports.h"
#include "main/context.h"
#include "main/macros.h"
#include "shader/program.h"
#include "shader/prog_instruction.h"
#include "shader/prog_parameter.h"
#include "shader/prog_print.h"
#include "slang_builtin.h"
#include "slang_emit.h"
#include "slang_mem.h"


#define PEEPHOLE_OPTIMIZATIONS 1
#define ANNOTATE 0


typedef struct
{
   slang_info_log *log;
   slang_var_table *vt;
   struct gl_program *prog;
   struct gl_program **Subroutines;
   GLuint NumSubroutines;

   /* code-gen options */
   GLboolean EmitHighLevelInstructions;
   GLboolean EmitCondCodes;
   GLboolean EmitComments;
   GLboolean EmitBeginEndSub; /* XXX TEMPORARY */
} slang_emit_info;



static struct gl_program *
new_subroutine(slang_emit_info *emitInfo, GLuint *id)
{
   GET_CURRENT_CONTEXT(ctx);
   const GLuint n = emitInfo->NumSubroutines;

   emitInfo->Subroutines = (struct gl_program **)
      _mesa_realloc(emitInfo->Subroutines,
                    n * sizeof(struct gl_program),
                    (n + 1) * sizeof(struct gl_program));
   emitInfo->Subroutines[n] = ctx->Driver.NewProgram(ctx, emitInfo->prog->Target, 0);
   emitInfo->Subroutines[n]->Parameters = emitInfo->prog->Parameters;
   emitInfo->NumSubroutines++;
   *id = n;
   return emitInfo->Subroutines[n];
}


/**
 * Convert a writemask to a swizzle.  Used for testing cond codes because
 * we only want to test the cond code component(s) that was set by the
 * previous instruction.
 */
static GLuint
writemask_to_swizzle(GLuint writemask)
{
   if (writemask == WRITEMASK_X)
      return SWIZZLE_XXXX;
   if (writemask == WRITEMASK_Y)
      return SWIZZLE_YYYY;
   if (writemask == WRITEMASK_Z)
      return SWIZZLE_ZZZZ;
   if (writemask == WRITEMASK_W)
      return SWIZZLE_WWWW;
   return SWIZZLE_XYZW;  /* shouldn't be hit */
}


/**
 * Swizzle a swizzle (function composition).
 * That is, return swz2(swz1), or said another way: swz1.szw2
 * Example: swizzle_swizzle(".zwxx", ".xxyw") yields ".zzwx"
 */
GLuint
_slang_swizzle_swizzle(GLuint swz1, GLuint swz2)
{
   GLuint i, swz, s[4];
   for (i = 0; i < 4; i++) {
      GLuint c = GET_SWZ(swz2, i);
      if (c <= SWIZZLE_W)
         s[i] = GET_SWZ(swz1, c);
      else
         s[i] = c;
   }
   swz = MAKE_SWIZZLE4(s[0], s[1], s[2], s[3]);
   return swz;
}


/**
 * Allocate storage for the given node (if it hasn't already been allocated).
 *
 * Typically this is temporary storage for an intermediate result (such as
 * for a multiply or add, etc).
 *
 * If n->Store does not exist it will be created and will be of the size
 * specified by defaultSize.
 */
static GLboolean
alloc_node_storage(slang_emit_info *emitInfo, slang_ir_node *n,
                   GLint defaultSize)
{
   assert(!n->Var);
   if (!n->Store) {
      assert(defaultSize > 0);
      n->Store = _slang_new_ir_storage(PROGRAM_TEMPORARY, -1, defaultSize);
   }

   /* now allocate actual register(s).  I.e. set n->Store->Index >= 0 */
   if (n->Store->Index < 0) {
      if (!_slang_alloc_temp(emitInfo->vt, n->Store)) {
         slang_info_log_error(emitInfo->log,
                              "Ran out of registers, too many temporaries");
         _slang_free(n->Store);
         n->Store = NULL;
         return GL_FALSE;
      }
   }
   return GL_TRUE;
}


/**
 * Free temporary storage, if n->Store is, in fact, temp storage.
 * Otherwise, no-op.
 */
static void
free_node_storage(slang_var_table *vt, slang_ir_node *n)
{
   if (n->Store->File == PROGRAM_TEMPORARY &&
       n->Store->Index >= 0 &&
       n->Opcode != IR_SWIZZLE) {
      if (_slang_is_temp(vt, n->Store)) {
         _slang_free_temp(vt, n->Store);
         n->Store->Index = -1;
         n->Store = NULL; /* XXX this may not be needed */
      }
   }
}


/**
 * Helper function to allocate a short-term temporary.
 * Free it with _slang_free_temp().
 */
static GLboolean
alloc_local_temp(slang_emit_info *emitInfo, slang_ir_storage *temp, GLint size)
{
   assert(size >= 1);
   assert(size <= 4);
   _mesa_bzero(temp, sizeof(*temp));
   temp->Size = size;
   temp->File = PROGRAM_TEMPORARY;
   temp->Index = -1;
   return _slang_alloc_temp(emitInfo->vt, temp);
}


/**
 * Remove any SWIZZLE_NIL terms from given swizzle mask.
 * For a swizzle like .z??? generate .zzzz (replicate single component).
 * Else, for .wx?? generate .wxzw (insert default component for the position).
 */
static GLuint
fix_swizzle(GLuint swizzle)
{
   GLuint c0 = GET_SWZ(swizzle, 0),
      c1 = GET_SWZ(swizzle, 1),
      c2 = GET_SWZ(swizzle, 2),
      c3 = GET_SWZ(swizzle, 3);
   if (c1 == SWIZZLE_NIL && c2 == SWIZZLE_NIL && c3 == SWIZZLE_NIL) {
      /* smear first component across all positions */
      c1 = c2 = c3 = c0;
   }
   else {
      /* insert default swizzle components */
      if (c0 == SWIZZLE_NIL)
         c0 = SWIZZLE_X;
      if (c1 == SWIZZLE_NIL)
         c1 = SWIZZLE_Y;
      if (c2 == SWIZZLE_NIL)
         c2 = SWIZZLE_Z;
      if (c3 == SWIZZLE_NIL)
         c3 = SWIZZLE_W;
   }
   return MAKE_SWIZZLE4(c0, c1, c2, c3);
}



/**
 * Convert IR storage to an instruction dst register.
 */
static void
storage_to_dst_reg(struct prog_dst_register *dst, const slang_ir_storage *st,
                   GLuint writemask)
{
   const GLint size = st->Size;
   GLint index = st->Index;
   GLuint swizzle = st->Swizzle;

   /* if this is storage relative to some parent storage, walk up the tree */
   while (st->Parent) {
      st = st->Parent;
      index += st->Index;
      swizzle = _slang_swizzle_swizzle(st->Swizzle, swizzle);
   }

   assert(st->File != PROGRAM_UNDEFINED);
   dst->File = st->File;

   assert(index >= 0);
   dst->Index = index;

   assert(size >= 1);
   assert(size <= 4);

   if (size == 1) {
      GLuint comp = GET_SWZ(swizzle, 0);
      assert(comp < 4);
      dst->WriteMask = WRITEMASK_X << comp;
   }
   else {
      dst->WriteMask = writemask;
   }
}


/**
 * Convert IR storage to an instruction src register.
 */
static void
storage_to_src_reg(struct prog_src_register *src, const slang_ir_storage *st)
{
   const GLboolean relAddr = st->RelAddr;
   GLint index = st->Index;
   GLuint swizzle = st->Swizzle;

   /* if this is storage relative to some parent storage, walk up the tree */
   while (st->Parent) {
      st = st->Parent;
      index += st->Index;
      swizzle = _slang_swizzle_swizzle(fix_swizzle(st->Swizzle), swizzle);
   }

   assert(st->File >= 0);
#if 1 /* XXX temporary */
   if (st->File == PROGRAM_UNDEFINED) {
      slang_ir_storage *st0 = (slang_ir_storage *) st;
      st0->File = PROGRAM_TEMPORARY;
   }
#endif
   assert(st->File < PROGRAM_UNDEFINED);
   src->File = st->File;

   assert(index >= 0);
   src->Index = index;

   swizzle = fix_swizzle(swizzle);
   assert(GET_SWZ(swizzle, 0) <= SWIZZLE_W);
   assert(GET_SWZ(swizzle, 1) <= SWIZZLE_W);
   assert(GET_SWZ(swizzle, 2) <= SWIZZLE_W);
   assert(GET_SWZ(swizzle, 3) <= SWIZZLE_W);
   src->Swizzle = swizzle;

   src->RelAddr = relAddr;
}


/*
 * Setup an instrucion src register to point to a scalar constant.
 */
static void
constant_to_src_reg(struct prog_src_register *src, GLfloat val,
                    slang_emit_info *emitInfo)
{
   GLuint zeroSwizzle;
   GLint zeroReg;
   GLfloat value[4];

   value[0] = val;
   zeroReg = _mesa_add_unnamed_constant(emitInfo->prog->Parameters,
                                        value, 1, &zeroSwizzle);
   assert(zeroReg >= 0);

   src->File = PROGRAM_CONSTANT;
   src->Index = zeroReg;
   src->Swizzle = zeroSwizzle;
}


/**
 * Add new instruction at end of given program.
 * \param prog  the program to append instruction onto
 * \param opcode  opcode for the new instruction
 * \return pointer to the new instruction
 */
static struct prog_instruction *
new_instruction(slang_emit_info *emitInfo, gl_inst_opcode opcode)
{
   struct gl_program *prog = emitInfo->prog;
   struct prog_instruction *inst;

#if 0
   /* print prev inst */
   if (prog->NumInstructions > 0) {
      _mesa_print_instruction(prog->Instructions + prog->NumInstructions - 1);
   }
#endif
   prog->Instructions = _mesa_realloc_instructions(prog->Instructions,
                                                   prog->NumInstructions,
                                                   prog->NumInstructions + 1);
   inst = prog->Instructions + prog->NumInstructions;
   prog->NumInstructions++;
   _mesa_init_instructions(inst, 1);
   inst->Opcode = opcode;
   inst->BranchTarget = -1; /* invalid */
   /*
   printf("New inst %d: %p %s\n", prog->NumInstructions-1,(void*)inst,
          _mesa_opcode_string(inst->Opcode));
   */
   return inst;
}


/**
 * Return pointer to last instruction in program.
 */
static struct prog_instruction *
prev_instruction(slang_emit_info *emitInfo)
{
   struct gl_program *prog = emitInfo->prog;
   if (prog->NumInstructions == 0)
      return NULL;
   else
      return prog->Instructions + prog->NumInstructions - 1;
}


static struct prog_instruction *
emit(slang_emit_info *emitInfo, slang_ir_node *n);


/**
 * Return an annotation string for given node's storage.
 */
static char *
storage_annotation(const slang_ir_node *n, const struct gl_program *prog)
{
#if ANNOTATE
   const slang_ir_storage *st = n->Store;
   static char s[100] = "";

   if (!st)
      return _mesa_strdup("");

   switch (st->File) {
   case PROGRAM_CONSTANT:
      if (st->Index >= 0) {
         const GLfloat *val = prog->Parameters->ParameterValues[st->Index];
         if (st->Swizzle == SWIZZLE_NOOP)
            sprintf(s, "{%g, %g, %g, %g}", val[0], val[1], val[2], val[3]);
         else {
            sprintf(s, "%g", val[GET_SWZ(st->Swizzle, 0)]);
         }
      }
      break;
   case PROGRAM_TEMPORARY:
      if (n->Var)
         sprintf(s, "%s", (char *) n->Var->a_name);
      else
         sprintf(s, "t[%d]", st->Index);
      break;
   case PROGRAM_STATE_VAR:
   case PROGRAM_UNIFORM:
      sprintf(s, "%s", prog->Parameters->Parameters[st->Index].Name);
      break;
   case PROGRAM_VARYING:
      sprintf(s, "%s", prog->Varying->Parameters[st->Index].Name);
      break;
   case PROGRAM_INPUT:
      sprintf(s, "input[%d]", st->Index);
      break;
   case PROGRAM_OUTPUT:
      sprintf(s, "output[%d]", st->Index);
      break;
   default:
      s[0] = 0;
   }
   return _mesa_strdup(s);
#else
   return NULL;
#endif
}


/**
 * Return an annotation string for an instruction.
 */
static char *
instruction_annotation(gl_inst_opcode opcode, char *dstAnnot,
                       char *srcAnnot0, char *srcAnnot1, char *srcAnnot2)
{
#if ANNOTATE
   const char *operator;
   char *s;
   int len = 50;

   if (dstAnnot)
      len += strlen(dstAnnot);
   else
      dstAnnot = _mesa_strdup("");

   if (srcAnnot0)
      len += strlen(srcAnnot0);
   else
      srcAnnot0 = _mesa_strdup("");

   if (srcAnnot1)
      len += strlen(srcAnnot1);
   else
      srcAnnot1 = _mesa_strdup("");

   if (srcAnnot2)
      len += strlen(srcAnnot2);
   else
      srcAnnot2 = _mesa_strdup("");

   switch (opcode) {
   case OPCODE_ADD:
      operator = "+";
      break;
   case OPCODE_SUB:
      operator = "-";
      break;
   case OPCODE_MUL:
      operator = "*";
      break;
   case OPCODE_DP3:
      operator = "DP3";
      break;
   case OPCODE_DP4:
      operator = "DP4";
      break;
   case OPCODE_XPD:
      operator = "XPD";
      break;
   case OPCODE_RSQ:
      operator = "RSQ";
      break;
   case OPCODE_SGT:
      operator = ">";
      break;
   default:
      operator = ",";
   }

   s = (char *) malloc(len);
   sprintf(s, "%s = %s %s %s %s", dstAnnot,
           srcAnnot0, operator, srcAnnot1, srcAnnot2);
   assert(_mesa_strlen(s) < len);

   free(dstAnnot);
   free(srcAnnot0);
   free(srcAnnot1);
   free(srcAnnot2);