return;
}
+
+static void
+check_no_subroutines(const struct tgsi_full_instruction *inst)
+{
+ switch (inst->Instruction.Opcode) {
+ case TGSI_OPCODE_BGNSUB:
+ case TGSI_OPCODE_ENDSUB:
+ case TGSI_OPCODE_CAL:
+ unreachable("subroutines unhandled");
+ }
+}
+
+static unsigned
+get_inst_tessfactor_writemask(const struct tgsi_shader_info *info,
+ const struct tgsi_full_instruction *inst)
+{
+ unsigned writemask = 0;
+
+ for (unsigned i = 0; i < inst->Instruction.NumDstRegs; i++) {
+ const struct tgsi_full_dst_register *dst = &inst->Dst[i];
+
+ if (dst->Register.File == TGSI_FILE_OUTPUT &&
+ !dst->Register.Indirect) {
+ unsigned name = info->output_semantic_name[dst->Register.Index];
+
+ if (name == TGSI_SEMANTIC_TESSINNER)
+ writemask |= dst->Register.WriteMask;
+ else if (name == TGSI_SEMANTIC_TESSOUTER)
+ writemask |= dst->Register.WriteMask << 4;
+ }
+ }
+ return writemask;
+}
+
+static unsigned
+get_block_tessfactor_writemask(const struct tgsi_shader_info *info,
+ struct tgsi_parse_context *parse,
+ unsigned end_opcode)
+{
+ struct tgsi_full_instruction *inst;
+ unsigned writemask = 0;
+
+ do {
+ tgsi_parse_token(parse);
+ assert(parse->FullToken.Token.Type == TGSI_TOKEN_TYPE_INSTRUCTION);
+ inst = &parse->FullToken.FullInstruction;
+ check_no_subroutines(inst);
+
+ /* Recursively process nested blocks. */
+ switch (inst->Instruction.Opcode) {
+ case TGSI_OPCODE_IF:
+ case TGSI_OPCODE_UIF:
+ writemask |=
+ get_block_tessfactor_writemask(info, parse, TGSI_OPCODE_ENDIF);
+ continue;
+
+ case TGSI_OPCODE_BGNLOOP:
+ writemask |=
+ get_block_tessfactor_writemask(info, parse, TGSI_OPCODE_ENDLOOP);
+ continue;
+
+ case TGSI_OPCODE_BARRIER:
+ unreachable("nested BARRIER is illegal");
+ continue;
+ }
+
+ writemask |= get_inst_tessfactor_writemask(info, inst);
+ } while (inst->Instruction.Opcode != end_opcode);
+
+ return writemask;
+}
+
+static void
+get_if_block_tessfactor_writemask(const struct tgsi_shader_info *info,
+ struct tgsi_parse_context *parse,
+ unsigned *upper_block_tf_writemask,
+ unsigned *cond_block_tf_writemask)
+{
+ struct tgsi_full_instruction *inst;
+ unsigned then_tessfactor_writemask = 0;
+ unsigned else_tessfactor_writemask = 0;
+ bool is_then = true;
+
+ do {
+ tgsi_parse_token(parse);
+ assert(parse->FullToken.Token.Type == TGSI_TOKEN_TYPE_INSTRUCTION);
+ inst = &parse->FullToken.FullInstruction;
+ check_no_subroutines(inst);
+
+ switch (inst->Instruction.Opcode) {
+ case TGSI_OPCODE_ELSE:
+ is_then = false;
+ continue;
+
+ /* Recursively process nested blocks. */
+ case TGSI_OPCODE_IF:
+ case TGSI_OPCODE_UIF:
+ get_if_block_tessfactor_writemask(info, parse,
+ is_then ? &then_tessfactor_writemask :
+ &else_tessfactor_writemask,
+ cond_block_tf_writemask);
+ continue;
+
+ case TGSI_OPCODE_BGNLOOP:
+ *cond_block_tf_writemask |=
+ get_block_tessfactor_writemask(info, parse, TGSI_OPCODE_ENDLOOP);
+ continue;
+
+ case TGSI_OPCODE_BARRIER:
+ unreachable("nested BARRIER is illegal");
+ continue;
+ }
+
+ /* Process an instruction in the current block. */
+ unsigned writemask = get_inst_tessfactor_writemask(info, inst);
+
+ if (writemask) {
+ if (is_then)
+ then_tessfactor_writemask |= writemask;
+ else
+ else_tessfactor_writemask |= writemask;
+ }
+ } while (inst->Instruction.Opcode != TGSI_OPCODE_ENDIF);
+
+ if (then_tessfactor_writemask || else_tessfactor_writemask) {
+ /* If both statements write the same tess factor channels,
+ * we can say that the upper block writes them too. */
+ *upper_block_tf_writemask |= then_tessfactor_writemask &
+ else_tessfactor_writemask;
+ *cond_block_tf_writemask |= then_tessfactor_writemask |
+ else_tessfactor_writemask;
+ }
+}
+
+void
+tgsi_scan_tess_ctrl(const struct tgsi_token *tokens,
+ const struct tgsi_shader_info *info,
+ struct tgsi_tessctrl_info *out)
+{
+ memset(out, 0, sizeof(*out));
+
+ if (info->processor != PIPE_SHADER_TESS_CTRL)
+ return;
+
+ struct tgsi_parse_context parse;
+ if (tgsi_parse_init(&parse, tokens) != TGSI_PARSE_OK) {
+ debug_printf("tgsi_parse_init() failed in tgsi_scan_arrays()!\n");
+ return;
+ }
+
+ /* The pass works as follows:
+ * If all codepaths write tess factors, we can say that all invocations
+ * define tess factors.
+ *
+ * Each tess factor channel is tracked separately.
+ */
+ unsigned main_block_tf_writemask = 0; /* if main block writes tess factors */
+ unsigned cond_block_tf_writemask = 0; /* if cond block writes tess factors */
+
+ /* Initial value = true. Here the pass will accumulate results from multiple
+ * segments surrounded by barriers. If tess factors aren't written at all,
+ * it's a shader bug and we don't care if this will be true.
+ */
+ out->tessfactors_are_def_in_all_invocs = true;
+
+ while (!tgsi_parse_end_of_tokens(&parse)) {
+ tgsi_parse_token(&parse);
+
+ if (parse.FullToken.Token.Type != TGSI_TOKEN_TYPE_INSTRUCTION)
+ continue;
+
+ struct tgsi_full_instruction *inst = &parse.FullToken.FullInstruction;
+ check_no_subroutines(inst);
+
+ /* Process nested blocks. */
+ switch (inst->Instruction.Opcode) {
+ case TGSI_OPCODE_IF:
+ case TGSI_OPCODE_UIF:
+ get_if_block_tessfactor_writemask(info, &parse,
+ &main_block_tf_writemask,
+ &cond_block_tf_writemask);
+ continue;
+
+ case TGSI_OPCODE_BGNLOOP:
+ cond_block_tf_writemask |=
+ get_block_tessfactor_writemask(info, &parse, TGSI_OPCODE_ENDIF);
+ continue;
+
+ case TGSI_OPCODE_BARRIER:
+ /* The following case must be prevented:
+ * gl_TessLevelInner = ...;
+ * barrier();
+ * if (gl_InvocationID == 1)
+ * gl_TessLevelInner = ...;
+ *
+ * If you consider disjoint code segments separated by barriers, each
+ * such segment that writes tess factor channels should write the same
+ * channels in all codepaths within that segment.
+ */
+ if (main_block_tf_writemask || cond_block_tf_writemask) {
+ /* Accumulate the result: */
+ out->tessfactors_are_def_in_all_invocs &=
+ main_block_tf_writemask &&
+ !(cond_block_tf_writemask & ~main_block_tf_writemask);
+
+ /* Analyze the next code segment from scratch. */
+ main_block_tf_writemask = 0;
+ cond_block_tf_writemask = 0;
+ }
+ continue;
+ }
+
+ main_block_tf_writemask |= get_inst_tessfactor_writemask(info, inst);
+ }
+
+ /* Accumulate the result for the last code segment separated by a barrier. */
+ if (main_block_tf_writemask || cond_block_tf_writemask) {
+ out->tessfactors_are_def_in_all_invocs &=
+ main_block_tf_writemask &&
+ !(cond_block_tf_writemask & ~main_block_tf_writemask);
+ }
+
+ tgsi_parse_free(&parse);
+}
projects / mesa.git / commitdiff