Makefile: use ln -fs instead of cp to save space

this starts to matter for .odb files in the gigabytes size,
which will happen e.g. in exploration of mm^2 sized
ASAP7 designs with lots of empty space.

Empty space on a die can be common when exploring floorplans
and starting with an overgenerous placement of macros.

make works with softlinks: when the date is identical to
the target, i.e. it is up to date.

Files are only copied "forward" in the flow, so
this is safe.

tar works with hardlinks and softlinks: if the file does not exist in the
archive, then the full file is archived. Subsequent references
to the same file gets a hardlink. This should see "make issue"
sizes reduced.

A symlink is overwritten when a file is opened in write & truncate
mode, thus not changing the file that the symlink points to. This
is unlike a hard link.

Relative paths are used, such that the results folder
can be moved.

Signed-off-by: Øyvind Harboe <[email protected]>

Author: oharboe

flow/Makefile

@@ -399,11 +399,11 @@ $(RESULTS_DIR)/1_1_yosys.v: $(DONT_USE_LIBS) $(WRAPPED_LIBS) $(DONT_USE_SC_LIB)
 
 $(RESULTS_DIR)/1_synth.v: $(RESULTS_DIR)/1_1_yosys.v
 	mkdir -p $(RESULTS_DIR) $(LOG_DIR) $(REPORTS_DIR)
-	cp $< $@
+	ln -sf $(shell realpath --relative-to=$(dir $@) $<) $@
 
 $(RESULTS_DIR)/1_synth.sdc: $(SDC_FILE)
 	mkdir -p $(RESULTS_DIR) $(LOG_DIR) $(REPORTS_DIR)
-	cp $< $@
+	ln -sf $(shell realpath --relative-to=$(dir $@) $<) $@
 
 clean_synth:
 	rm -f  $(RESULTS_DIR)/1_*.v $(RESULTS_DIR)/1_synth.sdc
@@ -443,7 +443,7 @@ $(RESULTS_DIR)/2_2_floorplan_io.odb: $(RESULTS_DIR)/2_1_floorplan.odb $(IO_CONST
 ifndef IS_CHIP
 	($(TIME_CMD) $(OPENROAD_CMD) $(SCRIPTS_DIR)/io_placement_random.tcl -metrics $(LOG_DIR)/2_2_floorplan_io.json) 2>&1 | tee $(LOG_DIR)/2_2_floorplan_io.log
 else
-	cp $< $@
+	ln -sf $(shell realpath --relative-to=$(dir $@) $<) $@
 endif
 
 # STEP 3: Timing Driven Mixed Sized Placement
@@ -453,7 +453,7 @@ ifeq ($(MACRO_PLACEMENT),)
 	($(TIME_CMD) $(OPENROAD_CMD) $(SCRIPTS_DIR)/tdms_place.tcl -metrics $(LOG_DIR)/2_3_tdms.json) 2>&1 | tee $(LOG_DIR)/2_3_tdms_place.log
 else
 	$(info [INFO][FLOW] Using manual macro placement file $(MACRO_PLACEMENT))
-	cp $< $@
+	ln -sf $(shell realpath --relative-to=$(dir $@) $<) $@
 endif
 
 # STEP 4: Macro Placement
@@ -473,7 +473,7 @@ $(RESULTS_DIR)/2_6_floorplan_pdn.odb: $(RESULTS_DIR)/2_5_floorplan_tapcell.odb $
 	($(TIME_CMD) $(OPENROAD_CMD) $(SCRIPTS_DIR)/pdn.tcl -metrics $(LOG_DIR)/2_6_pdn.json) 2>&1 | tee $(LOG_DIR)/2_6_pdn.log
 
 $(RESULTS_DIR)/2_floorplan.odb: $(RESULTS_DIR)/2_6_floorplan_pdn.odb
-	cp $< $@
+	ln -sf $(shell realpath --relative-to=$(dir $@) $<) $@
 
 $(RESULTS_DIR)/2_floorplan.sdc: $(RESULTS_DIR)/2_1_floorplan.odb
 
@@ -506,7 +506,7 @@ $(RESULTS_DIR)/3_2_place_iop.odb: $(RESULTS_DIR)/3_1_place_gp_skip_io.odb $(IO_C
 ifndef IS_CHIP
 	($(TIME_CMD) $(OPENROAD_CMD) $(SCRIPTS_DIR)/io_placement.tcl -metrics $(LOG_DIR)/3_2_place_iop.json) 2>&1 | tee $(LOG_DIR)/3_2_place_iop.log
 else
-	cp $< $@
+	ln -sf $(shell realpath --relative-to=$(dir $@) $<) $@
 endif
 
 # STEP 3: Global placement with placed IOs, timing-driven, and routability-driven.
@@ -529,10 +529,10 @@ $(RESULTS_DIR)/3_5_place_dp.odb: $(RESULTS_DIR)/3_4_place_resized.odb
 	($(TIME_CMD) $(OPENROAD_CMD) $(SCRIPTS_DIR)/detail_place.tcl -metrics $(LOG_DIR)/3_5_opendp.json) 2>&1 | tee $(LOG_DIR)/3_5_opendp.log
 
 $(RESULTS_DIR)/3_place.odb: $(RESULTS_DIR)/3_5_place_dp.odb
-	cp $< $@
+	ln -sf $(shell realpath --relative-to=$(dir $@) $<) $@
 
 $(RESULTS_DIR)/3_place.sdc: $(RESULTS_DIR)/2_floorplan.sdc
-	cp $< $@
+	ln -sf $(shell realpath --relative-to=$(dir $@) $<) $@
 
 # Clean Targets
 #-------------------------------------------------------------------------------
@@ -570,7 +570,7 @@ $(RESULTS_DIR)/4_2_cts_fillcell.odb: $(RESULTS_DIR)/4_1_cts.odb
 $(RESULTS_DIR)/4_cts.sdc: $(RESULTS_DIR)/4_cts.odb
 
 $(RESULTS_DIR)/4_cts.odb: $(RESULTS_DIR)/4_2_cts_fillcell.odb
-	cp $< $@
+	ln -sf $(shell realpath --relative-to=$(dir $@) $<) $@
 
 .PHONY: clean_cts
 clean_cts:
@@ -608,10 +608,10 @@ endif
 	($(TIME_CMD) $(OPENROAD_CMD) $(SCRIPTS_DIR)/detail_route.tcl -metrics $(LOG_DIR)/5_2_TritonRoute.json) 2>&1 | tee $(LOG_DIR)/5_2_TritonRoute.log
 
 $(RESULTS_DIR)/5_route.odb: $(RESULTS_DIR)/5_2_route.odb
-	cp $< $@
+	ln -sf $(shell realpath --relative-to=$(dir $@) $<) $@
 
 $(RESULTS_DIR)/5_route.sdc: $(RESULTS_DIR)/4_cts.sdc
-	cp $< $@
+	ln -sf $(shell realpath --relative-to=$(dir $@) $<) $@
 
 $(RESULTS_DIR)/5_route.v:
 	@export OR_DB=5_route ;\
@@ -666,14 +666,14 @@ $(RESULTS_DIR)/6_1_fill.odb: $(RESULTS_DIR)/5_route.odb $(FILL_CONFIG)
 	($(TIME_CMD) $(OPENROAD_CMD) $(SCRIPTS_DIR)/density_fill.tcl -metrics $(LOG_DIR)/6_density_fill.json) 2>&1 | tee $(LOG_DIR)/6_density_fill.log
 else
 $(RESULTS_DIR)/6_1_fill.odb: $(RESULTS_DIR)/5_route.odb
-	cp $< $@
+	ln -sf $(shell realpath --relative-to=$(dir $@) $<) $@
 endif
 
 $(RESULTS_DIR)/6_1_fill.sdc: $(RESULTS_DIR)/5_route.sdc
-	cp $< $@
+	ln -sf $(shell realpath --relative-to=$(dir $@) $<) $@
 
 $(RESULTS_DIR)/6_final.sdc: $(RESULTS_DIR)/5_route.sdc
-	cp $< $@
+	ln -sf $(shell realpath --relative-to=$(dir $@) $<) $@
 
 $(LOG_DIR)/6_report.log: $(RESULTS_DIR)/6_1_fill.odb $(RESULTS_DIR)/6_1_fill.sdc
 	($(TIME_CMD) $(OPENROAD_CMD) $(SCRIPTS_DIR)/final_report.tcl -metrics $(LOG_DIR)/6_report.json) 2>&1 | tee $(LOG_DIR)/6_report.log
@@ -690,17 +690,17 @@ skip_resize: $(RESULTS_DIR)/3_3_place_gp.odb
 .PHONY: skip_cts
 skip_cts: $(RESULTS_DIR)/3_place.odb $(RESULTS_DIR)/3_place.sdc
 	# mock all intermediate results
-	cp $(RESULTS_DIR)/3_place.odb $(RESULTS_DIR)/4_1_cts.odb
-	cp $(RESULTS_DIR)/3_place.odb $(RESULTS_DIR)/4_2_cts_fillcell.odb
-	cp $(RESULTS_DIR)/3_place.sdc $(RESULTS_DIR)/4_cts.sdc
-	cp $(RESULTS_DIR)/3_place.odb $(RESULTS_DIR)/4_cts.odb
+	cd $(RESULTS_DIR) && ln -sf 3_place.odb 4_1_cts.odb
+	cd $(RESULTS_DIR) && ln -sf 3_place.odb 4_2_cts_fillcell.odb
+	cd $(RESULTS_DIR) && ln -sf 3_place.sdc 4_cts.sdc
+	cd $(RESULTS_DIR) && ln -sf 3_place.odb 4_cts.odb
 
 # Skipping route can be useful to create a mock abstract
 .PHONY: skip_route
 skip_route: $(RESULTS_DIR)/4_cts.odb $(RESULTS_DIR)/4_cts.sdc
-	cp $(RESULTS_DIR)/3_place.odb $(RESULTS_DIR)/5_1_grt.odb
-	cp $(RESULTS_DIR)/3_place.odb $(RESULTS_DIR)/5_2_route.odb
-	cp $(RESULTS_DIR)/3_place.odb $(RESULTS_DIR)/6_1_fill.odb
+	cd $(RESULTS_DIR) && ln -sf 3_place.odb 5_1_grt.odb
+	cd $(RESULTS_DIR) && ln -sf 3_place.odb 5_2_route.odb
+	cd $(RESULTS_DIR) && ln -sf 3_place.odb 6_1_fill.odb
 	touch $(RESULTS_DIR)/6_final.spef
 
 # To create a mock abstract quickly, good enough to iterate quickly on
@@ -743,7 +743,7 @@ $(GDS_MERGED_FILE): $(RESULTS_DIR)/6_final.def $(OBJECTS_DIR)/klayout.lyt $(GDSO
 $(RESULTS_DIR)/6_final.v: $(LOG_DIR)/6_report.log
 
 $(GDS_FINAL_FILE): $(GDS_MERGED_FILE)
-	cp $< $@
+	ln -sf $(shell realpath --relative-to=$(dir $@) $<) $@
 
 .PHONY: drc
 drc: $(REPORTS_DIR)/6_drc.lyrdb