Merge pull request #2453 from Pinata-Consulting/makefile-synth-simplify

makefile: .sdc is copied in synthesis, consistent with other stages

Author: maliberty

flow/Makefile

@@ -448,8 +448,7 @@ $(WRAPPED_LIBS):
 # |____/ |_| |_| \_| |_| |_| |_|_____|____/___|____/
 #
 .PHONY: synth
-synth: $(RESULTS_DIR)/1_synth.v \
-       $(RESULTS_DIR)/1_synth.sdc
+synth: $(RESULTS_DIR)/1_synth.v
 
 .PHONY: synth-report
 synth-report: synth
@@ -506,10 +505,6 @@ $(RESULTS_DIR)/1_synth.rtlil: $(YOSYS_DEPENDENCIES)
 $(RESULTS_DIR)/1_1_yosys.v: $(RESULTS_DIR)/1_synth.rtlil
 	$(UNSET_AND_MAKE) do-yosys-keep-hierarchy do-yosys
 
-$(RESULTS_DIR)/1_synth.sdc: $(SDC_FILE)
-	mkdir -p $(RESULTS_DIR)
-	cp $(SDC_FILE) $(RESULTS_DIR)/1_synth.sdc
-
 .PHONY: do-synth
 do-synth:
 	mkdir -p $(RESULTS_DIR) $(LOG_DIR) $(REPORTS_DIR)

flow/scripts/synth.tcl

@@ -76,3 +76,7 @@ tee -o $::env(REPORTS_DIR)/synth_stat.txt stat {*}$stat_libs
 
 # Write synthesized design
 write_verilog -noexpr -nohex -nodec $::env(RESULTS_DIR)/1_1_yosys.v
+# One day a more sophisticated synthesis will write out a modified
+# .sdc file after synthesis. For now, just copy the input .sdc file,
+# making synthesis more consistent with other stages.
+log_cmd exec cp $::env(SDC_FILE) $::env(RESULTS_DIR)/1_synth.sdc