--- /dev/null
+/*
+ * Mesa 3-D graphics library
+ * Version: 7.5
+ *
+ * Copyright (C) 2009 VMware, Inc. 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
+ * VMWARE 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 "main/glheader.h"
+#include "main/context.h"
+#include "main/macros.h"
+#include "program.h"
+#include "prog_instruction.h"
+#include "prog_optimize.h"
+#include "prog_print.h"
+
+
+static GLboolean dbg = GL_FALSE;
+
+
+/**
+ * In 'prog' remove instruction[i] if removeFlags[i] == TRUE.
+ * \return number of instructions removed
+ */
+static GLuint
+remove_instructions(struct gl_program *prog, const GLboolean *removeFlags)
+{
+ GLint i, removeEnd = 0, removeCount = 0;
+ GLuint totalRemoved = 0;
+
+ /* go backward */
+ for (i = prog->NumInstructions - 1; i >= 0; i--) {
+ if (removeFlags[i]) {
+ totalRemoved++;
+ if (removeCount == 0) {
+ /* begin a run of instructions to remove */
+ removeEnd = i;
+ removeCount = 1;
+ }
+ else {
+ /* extend the run of instructions to remove */
+ removeCount++;
+ }
+ }
+ else {
+ /* don't remove this instruction, but check if the preceeding
+ * instructions are to be removed.
+ */
+ if (removeCount > 0) {
+ GLint removeStart = removeEnd - removeCount + 1;
+ _mesa_delete_instructions(prog, removeStart, removeCount);
+ removeStart = removeCount = 0; /* reset removal info */
+ }
+ }
+ }
+ return totalRemoved;
+}
+
+
+/**
+ * Consolidate temporary registers to use low numbers. For example, if the
+ * shader only uses temps 4, 5, 8, replace them with 0, 1, 2.
+ */
+static void
+_mesa_consolidate_registers(struct gl_program *prog)
+{
+ GLboolean tempUsed[MAX_PROGRAM_TEMPS];
+ GLuint tempMap[MAX_PROGRAM_TEMPS];
+ GLuint tempMax = 0, i;
+
+ if (dbg) {
+ _mesa_printf("Optimize: Begin register consolidation\n");
+ }
+
+ memset(tempUsed, 0, sizeof(tempUsed));
+
+ /* set tempUsed[i] if temporary [i] is referenced */
+ for (i = 0; i < prog->NumInstructions; i++) {
+ const struct prog_instruction *inst = prog->Instructions + i;
+ const GLuint numSrc = _mesa_num_inst_src_regs(inst->Opcode);
+ GLuint j;
+ for (j = 0; j < numSrc; j++) {
+ if (inst->SrcReg[j].File == PROGRAM_TEMPORARY) {
+ const GLuint index = inst->SrcReg[j].Index;
+ ASSERT(index < MAX_PROGRAM_TEMPS);
+ tempUsed[index] = GL_TRUE;
+ tempMax = MAX2(tempMax, index);
+ break;
+ }
+ }
+ if (inst->DstReg.File == PROGRAM_TEMPORARY) {
+ const GLuint index = inst->DstReg.Index;
+ ASSERT(index < MAX_PROGRAM_TEMPS);
+ tempUsed[index] = GL_TRUE;
+ tempMax = MAX2(tempMax, index);
+ }
+ }
+
+ /* allocate a new index for each temp that's used */
+ {
+ GLuint freeTemp = 0;
+ for (i = 0; i <= tempMax; i++) {
+ if (tempUsed[i]) {
+ tempMap[i] = freeTemp++;
+ /*_mesa_printf("replace %u with %u\n", i, tempMap[i]);*/
+ }
+ }
+ if (freeTemp == tempMax + 1) {
+ /* no consolidation possible */
+ return;
+ }
+ if (dbg) {
+ _mesa_printf("Replace regs 0..%u with 0..%u\n", tempMax, freeTemp-1);
+ }
+ }
+
+ /* now replace occurances of old temp indexes with new indexes */
+ for (i = 0; i < prog->NumInstructions; i++) {
+ struct prog_instruction *inst = prog->Instructions + i;
+ const GLuint numSrc = _mesa_num_inst_src_regs(inst->Opcode);
+ GLuint j;
+ for (j = 0; j < numSrc; j++) {
+ if (inst->SrcReg[j].File == PROGRAM_TEMPORARY) {
+ GLuint index = inst->SrcReg[j].Index;
+ assert(index <= tempMax);
+ assert(tempUsed[index]);
+ inst->SrcReg[j].Index = tempMap[index];
+ }
+ }
+ if (inst->DstReg.File == PROGRAM_TEMPORARY) {
+ const GLuint index = inst->DstReg.Index;
+ assert(tempUsed[index]);
+ assert(index <= tempMax);
+ inst->DstReg.Index = tempMap[index];
+ }
+ }
+ if (dbg) {
+ _mesa_printf("Optimize: End register consolidation\n");
+ }
+}
+
+
+/**
+ * Remove dead instructions from the given program.
+ * This is very primitive for now. Basically look for temp registers
+ * that are written to but never read. Remove any instructions that
+ * write to such registers. Be careful with condition code setters.
+ */
+static void
+_mesa_remove_dead_code(struct gl_program *prog)
+{
+ GLboolean tempWritten[MAX_PROGRAM_TEMPS], tempRead[MAX_PROGRAM_TEMPS];
+ GLboolean *removeInst; /* per-instruction removal flag */
+ GLuint i, rem;
+
+ memset(tempWritten, 0, sizeof(tempWritten));
+ memset(tempRead, 0, sizeof(tempRead));
+
+ if (dbg) {
+ _mesa_printf("Optimize: Begin dead code removal\n");
+ /*_mesa_print_program(prog);*/
+ }
+
+ removeInst = (GLboolean *)
+ _mesa_calloc(prog->NumInstructions * sizeof(GLboolean));
+
+ /* Determine which temps are read and written */
+ for (i = 0; i < prog->NumInstructions; i++) {
+ const struct prog_instruction *inst = prog->Instructions + i;
+ const GLuint numSrc = _mesa_num_inst_src_regs(inst->Opcode);
+ GLuint j;
+
+ /* check src regs */
+ for (j = 0; j < numSrc; j++) {
+ if (inst->SrcReg[j].File == PROGRAM_TEMPORARY) {
+ const GLuint index = inst->SrcReg[j].Index;
+ ASSERT(index < MAX_PROGRAM_TEMPS);
+
+ if (inst->SrcReg[j].RelAddr) {
+ if (dbg)
+ _mesa_printf("abort remove dead code (indirect temp)\n");
+ return;
+ }
+
+ tempRead[index] = GL_TRUE;
+ }
+ }
+
+ /* check dst reg */
+ if (inst->DstReg.File == PROGRAM_TEMPORARY) {
+ const GLuint index = inst->DstReg.Index;
+ ASSERT(index < MAX_PROGRAM_TEMPS);
+
+ if (inst->DstReg.RelAddr) {
+ if (dbg)
+ _mesa_printf("abort remove dead code (indirect temp)\n");
+ return;
+ }
+
+ tempWritten[index] = GL_TRUE;
+ if (inst->CondUpdate) {
+ /* If we're writing to this register and setting condition
+ * codes we cannot remove the instruction. Prevent removal
+ * by setting the 'read' flag.
+ */
+ tempRead[index] = GL_TRUE;
+ }
+ }
+ }
+
+ if (dbg) {
+ for (i = 0; i < MAX_PROGRAM_TEMPS; i++) {
+ if (tempWritten[i] && !tempRead[i])
+ _mesa_printf("Remove writes to tmp %u\n", i);
+ }
+ }
+
+ /* find instructions that write to dead registers, flag for removal */
+ for (i = 0; i < prog->NumInstructions; i++) {
+ const struct prog_instruction *inst = prog->Instructions + i;
+ if (inst->DstReg.File == PROGRAM_TEMPORARY) {
+ GLint index = inst->DstReg.Index;
+ removeInst[i] = (tempWritten[index] && !tempRead[index]);
+ if (dbg && removeInst[i]) {
+ _mesa_printf("Remove inst %u: ", i);
+ _mesa_print_instruction(inst);
+ }
+ }
+ }
+
+ /* now remove the instructions which aren't needed */
+ rem = remove_instructions(prog, removeInst);
+
+ _mesa_free(removeInst);
+
+ if (dbg) {
+ _mesa_printf("Optimize: End dead code removal. %u instructions removed\n", rem);
+ /*_mesa_print_program(prog);*/
+ }
+}
+
+
+enum temp_use
+{
+ READ,
+ WRITE,
+ FLOW,
+ END
+};
+
+/**
+ * Scan forward in program from 'start' for the next occurance of TEMP[index].
+ * Return READ, WRITE, FLOW or END to indicate the next usage or an indicator
+ * that we can't look further.
+ */
+static enum temp_use
+find_next_temp_use(const struct gl_program *prog, GLuint start, GLuint index)
+{
+ GLuint i;
+
+ for (i = start; i < prog->NumInstructions; i++) {
+ const struct prog_instruction *inst = prog->Instructions + i;
+ switch (inst->Opcode) {
+ case OPCODE_BGNLOOP:
+ case OPCODE_ENDLOOP:
+ case OPCODE_BGNSUB:
+ case OPCODE_ENDSUB:
+ return FLOW;
+ default:
+ {
+ const GLuint numSrc = _mesa_num_inst_src_regs(inst->Opcode);
+ GLuint j;
+ for (j = 0; j < numSrc; j++) {
+ if (inst->SrcReg[j].File == PROGRAM_TEMPORARY &&
+ inst->SrcReg[j].Index == index)
+ return READ;
+ }
+ if (inst->DstReg.File == PROGRAM_TEMPORARY &&
+ inst->DstReg.Index == index)
+ return WRITE;
+ }
+ }
+ }
+
+ return END;
+}
+
+
+/**
+ * Try to remove extraneous MOV instructions from the given program.
+ */
+static void
+_mesa_remove_extra_moves(struct gl_program *prog)
+{
+ GLboolean *removeInst; /* per-instruction removal flag */
+ GLuint i, rem, loopNesting = 0, subroutineNesting = 0;
+
+ if (dbg) {
+ _mesa_printf("Optimize: Begin remove extra moves\n");
+ _mesa_print_program(prog);
+ }
+
+ removeInst = (GLboolean *)
+ _mesa_calloc(prog->NumInstructions * sizeof(GLboolean));
+
+ /*
+ * Look for sequences such as this:
+ * FOO tmpX, arg0, arg1;
+ * MOV tmpY, tmpX;
+ * and convert into:
+ * FOO tmpY, arg0, arg1;
+ */
+
+ for (i = 0; i < prog->NumInstructions; i++) {
+ const struct prog_instruction *inst = prog->Instructions + i;
+
+ switch (inst->Opcode) {
+ case OPCODE_BGNLOOP:
+ loopNesting++;
+ break;
+ case OPCODE_ENDLOOP:
+ loopNesting--;
+ break;
+ case OPCODE_BGNSUB:
+ subroutineNesting++;
+ break;
+ case OPCODE_ENDSUB:
+ subroutineNesting--;
+ break;
+ case OPCODE_MOV:
+ if (i > 0 &&
+ loopNesting == 0 &&
+ subroutineNesting == 0 &&
+ inst->SrcReg[0].File == PROGRAM_TEMPORARY &&
+ inst->SrcReg[0].Swizzle == SWIZZLE_XYZW) {
+ /* see if this MOV can be removed */
+ const GLuint tempIndex = inst->SrcReg[0].Index;
+ struct prog_instruction *prevInst;
+ GLuint prevI;
+
+ /* get pointer to previous instruction */
+ prevI = i - 1;
+ while (removeInst[prevI] && prevI > 0)
+ prevI--;
+ prevInst = prog->Instructions + prevI;
+
+ if (prevInst->DstReg.File == PROGRAM_TEMPORARY &&
+ prevInst->DstReg.Index == tempIndex &&
+ prevInst->DstReg.WriteMask == WRITEMASK_XYZW) {
+
+ enum temp_use next_use =
+ find_next_temp_use(prog, i + 1, tempIndex);
+
+ if (next_use == WRITE || next_use == END) {
+ /* OK, we can safely remove this MOV instruction.
+ * Transform:
+ * prevI: FOO tempIndex, x, y;
+ * i: MOV z, tempIndex;
+ * Into:
+ * prevI: FOO z, x, y;
+ */
+
+ /* patch up prev inst */
+ prevInst->DstReg.File = inst->DstReg.File;
+ prevInst->DstReg.Index = inst->DstReg.Index;
+
+ /* flag this instruction for removal */
+ removeInst[i] = GL_TRUE;
+
+ if (dbg) {
+ _mesa_printf("Remove MOV at %u\n", i);
+ _mesa_printf("new prev inst %u: ", prevI);
+ _mesa_print_instruction(prevInst);
+ }
+ }
+ }
+ }
+ break;
+ default:
+ ; /* nothing */
+ }
+ }
+
+ /* now remove the instructions which aren't needed */
+ rem = remove_instructions(prog, removeInst);
+
+ if (dbg) {
+ _mesa_printf("Optimize: End remove extra moves. %u instructions removed\n", rem);
+ /*_mesa_print_program(prog);*/
+ }
+}
+
+
+/**
+ * Apply optimizations to the given program to eliminate unnecessary
+ * instructions, temp regs, etc.
+ */
+void
+_mesa_optimize_program(GLcontext *ctx, struct gl_program *program)
+{
+ if (1)
+ _mesa_remove_dead_code(program);
+
+ if (0) /* not test much yet */
+ _mesa_remove_extra_moves(program);
+
+ if (1)
+ _mesa_consolidate_registers(program);
+}
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