#include "prog_print.h"
+#define MAX_LOOP_NESTING 50
+
+
static GLboolean dbg = GL_FALSE;
}
+/**
+ * Remap register indexes according to map.
+ * \param prog the program to search/replace
+ * \param file the type of register file to search/replace
+ * \param map maps old register indexes to new indexes
+ */
+static void
+replace_regs(struct gl_program *prog, gl_register_file file, const GLint map[])
+{
+ GLuint i;
+
+ 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 == file) {
+ GLuint index = inst->SrcReg[j].Index;
+ ASSERT(map[index] >= 0);
+ inst->SrcReg[j].Index = map[index];
+ }
+ }
+ if (inst->DstReg.File == file) {
+ const GLuint index = inst->DstReg.Index;
+ ASSERT(map[index] >= 0);
+ inst->DstReg.Index = map[index];
+ }
+ }
+}
+
+
/**
* Consolidate temporary registers to use low numbers. For example, if the
* shader only uses temps 4, 5, 8, replace them with 0, 1, 2.
_mesa_consolidate_registers(struct gl_program *prog)
{
GLboolean tempUsed[MAX_PROGRAM_TEMPS];
- GLuint tempMap[MAX_PROGRAM_TEMPS];
+ GLint tempMap[MAX_PROGRAM_TEMPS];
GLuint tempMax = 0, i;
if (dbg) {
memset(tempUsed, 0, sizeof(tempUsed));
+ for (i = 0; i < MAX_PROGRAM_TEMPS; i++) {
+ tempMap[i] = -1;
+ }
+
/* set tempUsed[i] if temporary [i] is referenced */
for (i = 0; i < prog->NumInstructions; i++) {
const struct prog_instruction *inst = prog->Instructions + i;
}
}
- /* 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];
- }
- }
+ replace_regs(prog, PROGRAM_TEMPORARY, tempMap);
+
if (dbg) {
_mesa_printf("Optimize: End register consolidation\n");
}
}
+/** A live register interval */
+struct interval
+{
+ GLuint Reg; /** The temporary register index */
+ GLuint Start, End; /** Start/end instruction numbers */
+};
+
+
+/** A list of register intervals */
+struct interval_list
+{
+ GLuint Num;
+ struct interval Intervals[MAX_PROGRAM_TEMPS];
+};
+
+
+static void
+append_interval(struct interval_list *list, const struct interval *inv)
+{
+ list->Intervals[list->Num++] = *inv;
+}
+
+
+/** Insert interval inv into list, sorted by interval end */
+static void
+insert_interval_by_end(struct interval_list *list, const struct interval *inv)
+{
+ /* XXX we could do a binary search insertion here since list is sorted */
+ GLint i = list->Num - 1;
+ while (i >= 0 && list->Intervals[i].End > inv->End) {
+ list->Intervals[i + 1] = list->Intervals[i];
+ i--;
+ }
+ list->Intervals[i + 1] = *inv;
+ list->Num++;
+
+#ifdef DEBUG
+ {
+ GLuint i;
+ for (i = 0; i + 1 < list->Num; i++) {
+ ASSERT(list->Intervals[i].End <= list->Intervals[i + 1].End);
+ }
+ }
+#endif
+}
+
+
+/** Remove the given interval from the interval list */
+static void
+remove_interval(struct interval_list *list, const struct interval *inv)
+{
+ /* XXX we could binary search since list is sorted */
+ GLuint k;
+ for (k = 0; k < list->Num; k++) {
+ if (list->Intervals[k].Reg == inv->Reg) {
+ /* found, remove it */
+ ASSERT(list->Intervals[k].Start == inv->Start);
+ ASSERT(list->Intervals[k].End == inv->End);
+ while (k < list->Num - 1) {
+ list->Intervals[k] = list->Intervals[k + 1];
+ k++;
+ }
+ list->Num--;
+ return;
+ }
+ }
+}
+
+
+/** called by qsort() */
+static int
+compare_start(const void *a, const void *b)
+{
+ const struct interval *ia = (const struct interval *) a;
+ const struct interval *ib = (const struct interval *) b;
+ if (ia->Start < ib->Start)
+ return -1;
+ else if (ia->Start > ib->Start)
+ return +1;
+ else
+ return 0;
+}
+
+/** sort the interval list according to interval starts */
+static void
+sort_interval_list_by_start(struct interval_list *list)
+{
+ qsort(list->Intervals, list->Num, sizeof(struct interval), compare_start);
+#ifdef DEBUG
+ {
+ GLuint i;
+ for (i = 0; i + 1 < list->Num; i++) {
+ ASSERT(list->Intervals[i].Start <= list->Intervals[i + 1].Start);
+ }
+ }
+#endif
+}
+
+
+/**
+ * Update the intermediate interval info for register 'index' and
+ * instruction 'ic'.
+ */
+static void
+update_interval(GLint intBegin[], GLint intEnd[], GLuint index, GLuint ic)
+{
+ ASSERT(index < MAX_PROGRAM_TEMPS);
+ if (intBegin[index] == -1) {
+ ASSERT(intEnd[index] == -1);
+ intBegin[index] = intEnd[index] = ic;
+ }
+ else {
+ intEnd[index] = ic;
+ }
+}
+
+
+/**
+ * Find the live intervals for each temporary register in the program.
+ * For register R, the interval [A,B] indicates that R is referenced
+ * from instruction A through instruction B.
+ * Special consideration is needed for loops and subroutines.
+ * \return GL_TRUE if success, GL_FALSE if we cannot proceed for some reason
+ */
+static GLboolean
+find_live_intervals(struct gl_program *prog,
+ struct interval_list *liveIntervals)
+{
+ struct loop_info
+ {
+ GLuint Start, End; /**< Start, end instructions of loop */
+ };
+ struct loop_info loopStack[MAX_LOOP_NESTING];
+ GLuint loopStackDepth = 0;
+ GLint intBegin[MAX_PROGRAM_TEMPS], intEnd[MAX_PROGRAM_TEMPS];
+ GLuint i;
+
+ /*
+ * Note: we'll return GL_FALSE below if we find relative indexing
+ * into the TEMP register file. We can't handle that yet.
+ * We also give up on subroutines for now.
+ */
+
+ if (dbg) {
+ _mesa_printf("Optimize: Begin find intervals\n");
+ }
+
+ for (i = 0; i < MAX_PROGRAM_TEMPS; i++){
+ intBegin[i] = intEnd[i] = -1;
+ }
+
+ /* Scan instructions looking for temporary registers */
+ for (i = 0; i < prog->NumInstructions; i++) {
+ const struct prog_instruction *inst = prog->Instructions + i;
+ if (inst->Opcode == OPCODE_BGNLOOP) {
+ loopStack[loopStackDepth].Start = i;
+ loopStack[loopStackDepth].End = inst->BranchTarget;
+ loopStackDepth++;
+ }
+ else if (inst->Opcode == OPCODE_ENDLOOP) {
+ loopStackDepth--;
+ }
+ else if (inst->Opcode == OPCODE_CAL) {
+ return GL_FALSE;
+ }
+ else {
+ 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;
+ if (inst->SrcReg[j].RelAddr)
+ return GL_FALSE;
+ update_interval(intBegin, intEnd, index, i);
+ if (loopStackDepth > 0) {
+ /* extend temp register's interval to end of loop */
+ GLuint loopEnd = loopStack[loopStackDepth - 1].End;
+ update_interval(intBegin, intEnd, index, loopEnd);
+ }
+ }
+ }
+ if (inst->DstReg.File == PROGRAM_TEMPORARY) {
+ const GLuint index = inst->DstReg.Index;
+ if (inst->DstReg.RelAddr)
+ return GL_FALSE;
+ update_interval(intBegin, intEnd, index, i);
+ if (loopStackDepth > 0) {
+ /* extend temp register's interval to end of loop */
+ GLuint loopEnd = loopStack[loopStackDepth - 1].End;
+ update_interval(intBegin, intEnd, index, loopEnd);
+ }
+ }
+ }
+ }
+
+ /* Build live intervals list from intermediate arrays */
+ liveIntervals->Num = 0;
+ for (i = 0; i < MAX_PROGRAM_TEMPS; i++) {
+ if (intBegin[i] >= 0) {
+ struct interval inv;
+ inv.Reg = i;
+ inv.Start = intBegin[i];
+ inv.End = intEnd[i];
+ append_interval(liveIntervals, &inv);
+ }
+ }
+
+ /* Sort the list according to interval starts */
+ sort_interval_list_by_start(liveIntervals);
+
+ if (dbg) {
+ /* print interval info */
+ for (i = 0; i < liveIntervals->Num; i++) {
+ const struct interval *inv = liveIntervals->Intervals + i;
+ _mesa_printf("Reg[%d] live [%d, %d]:",
+ inv->Reg, inv->Start, inv->End);
+ if (1) {
+ int j;
+ for (j = 0; j < inv->Start; j++)
+ _mesa_printf(" ");
+ for (j = inv->Start; j <= inv->End; j++)
+ _mesa_printf("x");
+ }
+ _mesa_printf("\n");
+ }
+ }
+
+ return GL_TRUE;
+}
+
+
+static GLuint
+alloc_register(GLboolean usedRegs[MAX_PROGRAM_TEMPS])
+{
+ GLuint k;
+ for (k = 0; k < MAX_PROGRAM_TEMPS; k++) {
+ if (!usedRegs[k]) {
+ usedRegs[k] = GL_TRUE;
+ return k;
+ }
+ }
+ return MAX_PROGRAM_TEMPS;
+}
+
+
+/**
+ * This function implements "Linear Scan Register Allocation" to reduce
+ * the number of temporary registers used by the program.
+ *
+ * We compute the "live interval" for all temporary registers then
+ * examine the overlap of the intervals to allocate new registers.
+ * Basically, if two intervals do not overlap, they can use the same register.
+ */
+static void
+_mesa_reallocate_registers(struct gl_program *prog)
+{
+ struct interval_list liveIntervals;
+ GLint registerMap[MAX_PROGRAM_TEMPS];
+ GLboolean usedRegs[MAX_PROGRAM_TEMPS];
+ GLuint i;
+ GLuint maxTemp = 0;
+
+ if (dbg) {
+ _mesa_printf("Optimize: Begin live-interval register reallocation\n");
+ _mesa_print_program(prog);
+ }
+
+ for (i = 0; i < MAX_PROGRAM_TEMPS; i++){
+ registerMap[i] = -1;
+ usedRegs[i] = GL_FALSE;
+ }
+
+ if (!find_live_intervals(prog, &liveIntervals)) {
+ if (dbg)
+ _mesa_printf("Aborting register reallocation\n");
+ return;
+ }
+
+ {
+ struct interval_list activeIntervals;
+ activeIntervals.Num = 0;
+
+ /* loop over live intervals, allocating a new register for each */
+ for (i = 0; i < liveIntervals.Num; i++) {
+ const struct interval *live = liveIntervals.Intervals + i;
+
+ if (dbg)
+ _mesa_printf("Consider register %u\n", live->Reg);
+
+ /* Expire old intervals. Intervals which have ended with respect
+ * to the live interval can have their remapped registers freed.
+ */
+ {
+ GLint j;
+ for (j = 0; j < activeIntervals.Num; j++) {
+ const struct interval *inv = activeIntervals.Intervals + j;
+ if (inv->End >= live->Start) {
+ /* Stop now. Since the activeInterval list is sorted
+ * we know we don't have to go further.
+ */
+ break;
+ }
+ else {
+ /* Interval 'inv' has expired */
+ const GLint regNew = registerMap[inv->Reg];
+ ASSERT(regNew >= 0);
+
+ if (dbg)
+ _mesa_printf(" expire interval for reg %u\n", inv->Reg);
+
+ /* remove interval j from active list */
+ remove_interval(&activeIntervals, inv);
+ j--; /* counter-act j++ in for-loop above */
+
+ /* return register regNew to the free pool */
+ if (dbg)
+ _mesa_printf(" free reg %d\n", regNew);
+ ASSERT(usedRegs[regNew] == GL_TRUE);
+ usedRegs[regNew] = GL_FALSE;
+ }
+ }
+ }
+
+ /* find a free register for this live interval */
+ {
+ const GLuint k = alloc_register(usedRegs);
+ if (k == MAX_PROGRAM_TEMPS) {
+ /* out of registers, give up */
+ return;
+ }
+ registerMap[live->Reg] = k;
+ maxTemp = MAX2(maxTemp, k);
+ if (dbg)
+ _mesa_printf(" remap register %d -> %d\n", live->Reg, k);
+ }
+
+ /* Insert this live interval into the active list which is sorted
+ * by increasing end points.
+ */
+ insert_interval_by_end(&activeIntervals, live);
+ }
+ }
+
+ if (maxTemp + 1 < liveIntervals.Num) {
+ /* OK, we've reduced the number of registers needed.
+ * Scan the program and replace all the old temporary register
+ * indexes with the new indexes.
+ */
+ replace_regs(prog, PROGRAM_TEMPORARY, registerMap);
+
+ prog->NumTemporaries = maxTemp + 1;
+ }
+
+ if (dbg) {
+ _mesa_printf("Optimize: End live-interval register reallocation\n");
+ _mesa_printf("Num temp regs before: %u after: %u\n",
+ liveIntervals.Num, maxTemp + 1);
+ _mesa_print_program(prog);
+ }
+}
+
+
+
+
/**
* Apply optimizations to the given program to eliminate unnecessary
* instructions, temp regs, etc.
if (1)
_mesa_consolidate_registers(program);
+ else /*NEW*/
+ _mesa_reallocate_registers(program);
}
projects / mesa.git / commitdiff