Merge pull request #4270 from The-OpenROAD-Project-staging/secure-syn-bringup

maliberty · web-flow · commit ff182f883aa7 · 2026-06-13T23:30:01.000Z
Opt in first 8 designs to use 'syn'
diff --git a/docs/user/FlowVariables.md b/docs/user/FlowVariables.md
@@ -310,6 +310,7 @@ configuration file.
 | <a name="SYNTH_RETIME_MODULES"></a>SYNTH_RETIME_MODULES| *This is an experimental option and may cause adverse effects.* *No effort has been made to check if the retimed RTL is logically equivalent to the non-retimed RTL.* List of modules to apply automatic retiming to. These modules must not get dissolved and as such they should either be the top module or be included in SYNTH_KEEP_MODULES. The main use case is to quickly identify if performance can be improved by manually retiming the input RTL. Retiming will treat module ports like register endpoints/startpoints. The objective function of retiming isn't informed by SDC, even the clock period is ignored. As such, retiming will optimize for best delay at potentially high register number cost. Automatic retiming can produce suboptimal results as its timing model is crude and it doesn't find the optimal distribution of registers on long pipelines. See OR discussion  # 8080.| |
 | <a name="SYNTH_SKIP_KEEP"></a>SYNTH_SKIP_KEEP| Only meaningful together with SYNTH_CHECKPOINT. When set, signals that the supplied checkpoint is still canonical RTLIL (coarse synth and `keep_hierarchy` have not been run yet), so synth.tcl runs the full coarse+fine synthesis flattened. When unset and SYNTH_CHECKPOINT is used, synth.tcl assumes the checkpoint already has coarse synth + `keep_hierarchy` done and resumes from `coarse:fine`.| 0|
 | <a name="SYNTH_SLANG_ARGS"></a>SYNTH_SLANG_ARGS| Additional arguments passed to the slang frontend during synthesis.| |
+| <a name="SYNTH_USE_SYN"></a>SYNTH_USE_SYN| If set to 1, run synthesis using the "syn" tool built into OpenROAD (the synth_syn.tcl flow) instead of the default Yosys-based flow. Defaults to 0 (Yosys flow).| 0|
 | <a name="SYNTH_WRAPPED_ADDERS"></a>SYNTH_WRAPPED_ADDERS| Specify the adder modules that can be used for synthesis, separated by commas. The default adder module is determined by the first element of this variable.| |
 | <a name="SYNTH_WRAPPED_MULTIPLIERS"></a>SYNTH_WRAPPED_MULTIPLIERS| Specify the multiplier modules that can be used for synthesis, separated by commas. The default multiplier module is determined by the first element of this variable.| |
 | <a name="SYNTH_WRAPPED_OPERATORS"></a>SYNTH_WRAPPED_OPERATORS| Synthesize multiple architectural options for each arithmetic operator in the design. These options are available for switching among in later stages of the flow.| |
@@ -348,6 +349,7 @@ configuration file.
 - [PRE_SYNTH_TCL](#PRE_SYNTH_TCL)
 - [SDC_FILE](#SDC_FILE)
 - [SDC_GUT](#SDC_GUT)
+- [SKIP_REPORT_METRICS](#SKIP_REPORT_METRICS)
 - [SLANG_PLUGIN_PATH](#SLANG_PLUGIN_PATH)
 - [SYNTH_ARGS](#SYNTH_ARGS)
 - [SYNTH_BLACKBOXES](#SYNTH_BLACKBOXES)
@@ -370,6 +372,7 @@ configuration file.
 - [SYNTH_RETIME_MODULES](#SYNTH_RETIME_MODULES)
 - [SYNTH_SKIP_KEEP](#SYNTH_SKIP_KEEP)
 - [SYNTH_SLANG_ARGS](#SYNTH_SLANG_ARGS)
+- [SYNTH_USE_SYN](#SYNTH_USE_SYN)
 - [SYNTH_WRAPPED_ADDERS](#SYNTH_WRAPPED_ADDERS)
 - [SYNTH_WRAPPED_MULTIPLIERS](#SYNTH_WRAPPED_MULTIPLIERS)
 - [TIEHI_CELL_AND_PORT](#TIEHI_CELL_AND_PORT)
diff --git a/flow/Makefile b/flow/Makefile
@@ -404,7 +404,11 @@ floorplan_to_place: $(RESULTS_DIR)/1_synth.odb $(RESULTS_DIR)/1_synth.sdc
 
 # ==============================================================================
 
+ifeq ($(SYNTH_USE_SYN),1)
+$(eval $(call do-step,1_synth,$(VERILOG_FILES) $(SDC_FILE) $(TECH_LEF) $(SC_LEF) $(ADDITIONAL_LEFS) $(LIB_FILES),synth_syn))
+else
 $(eval $(call do-step,1_synth,$(RESULTS_DIR)/1_2_yosys.v $(RESULTS_DIR)/1_2_yosys.sdc $(TECH_LEF) $(SC_LEF) $(ADDITIONAL_LEFS) $(LIB_FILES),synth_odb))
+endif
 
 $(RESULTS_DIR)/1_synth.sdc: $(RESULTS_DIR)/1_synth.odb
 
diff --git a/flow/designs/asap7/aes/config.mk b/flow/designs/asap7/aes/config.mk
@@ -6,8 +6,6 @@ export DESIGN_NICKNAME        = aes
 export VERILOG_FILES = $(sort $(wildcard $(DESIGN_HOME)/src/$(DESIGN_NICKNAME)/*.v))
 export SDC_FILE      = $(DESIGN_HOME)/$(PLATFORM)/$(DESIGN_NICKNAME)/constraint.sdc
 
-export ABC_AREA                 = 1
-
 export CORE_UTILIZATION         = 70
 export CORE_ASPECT_RATIO        = 1
 export CORE_MARGIN              = 2
@@ -27,3 +25,4 @@ else ifeq ($(FLOW_VARIANT),combine)
 	 $(WORK_HOME)/results/$(PLATFORM)/$(DESIGN_NICKNAME)/blackbox/1_synth.v
 endif
 
+export SYNTH_USE_SYN = 1
diff --git a/flow/designs/asap7/aes/rules-base.json b/flow/designs/asap7/aes/rules-base.json
@@ -1,11 +1,11 @@
 {
     "synth__canonical_netlist__hash": {
-        "value": "3882365f5e814a21a600274234b3a087270968d4",
+        "value": "N/A",
         "compare": "==",
         "level": "warning"
     },
     "synth__netlist__hash": {
-        "value": "a04d44da52dba7d4a701d80927ba32d1d89ef9a1",
+        "value": "N/A",
         "compare": "==",
         "level": "warning"
     },
@@ -62,7 +62,7 @@
         "compare": ">="
     },
     "globalroute__timing__setup__tns": {
-        "value": -76.6,
+        "value": -169.0,
         "compare": ">="
     },
     "globalroute__timing__hold__ws": {
diff --git a/flow/designs/asap7/aes_lvt/config.mk b/flow/designs/asap7/aes_lvt/config.mk
@@ -18,4 +18,4 @@ export ASAP7_USE_VT           = LVT
 
 export RECOVER_POWER          = 100
 
-
+export SYNTH_USE_SYN = 1
diff --git a/flow/designs/asap7/aes_lvt/rules-base.json b/flow/designs/asap7/aes_lvt/rules-base.json
@@ -1,11 +1,11 @@
 {
     "synth__canonical_netlist__hash": {
-        "value": "7cb97d6d20f0fb4831af6dc20aea1d411aecc09a",
+        "value": "N/A",
         "compare": "==",
         "level": "warning"
     },
     "synth__netlist__hash": {
-        "value": "d84684a5256bf993bde8bccdff31af8237663019",
+        "value": "N/A",
         "compare": "==",
         "level": "warning"
     },
diff --git a/flow/designs/asap7/gcd-ccs/rules-base.json b/flow/designs/asap7/gcd-ccs/rules-base.json
@@ -1,11 +1,11 @@
 {
     "synth__canonical_netlist__hash": {
-        "value": "9b1daddbf16520e983085be7f06a02bc2fc2e27a",
+        "value": "N/A",
         "compare": "==",
         "level": "warning"
     },
     "synth__netlist__hash": {
-        "value": "2d3fbf9f1b7357c0cadb1e193d984ae458d68fa8",
+        "value": "N/A",
         "compare": "==",
         "level": "warning"
     },
@@ -38,7 +38,7 @@
         "compare": "<="
     },
     "cts__timing__setup__ws": {
-        "value": -79.2,
+        "value": -101.0,
         "compare": ">="
     },
     "cts__timing__setup__tns": {
@@ -90,7 +90,7 @@
         "compare": "<="
     },
     "finish__timing__setup__ws": {
-        "value": -78.5,
+        "value": -96.4,
         "compare": ">="
     },
     "finish__timing__setup__tns": {
diff --git a/flow/designs/asap7/gcd/config.mk b/flow/designs/asap7/gcd/config.mk
@@ -16,3 +16,4 @@ export PLACE_DENSITY          = 0.35
 # few last gasp iterations
 export SKIP_LAST_GASP ?= 1
 
+export SYNTH_USE_SYN = 1
diff --git a/flow/designs/asap7/gcd/rules-base.json b/flow/designs/asap7/gcd/rules-base.json
@@ -1,11 +1,11 @@
 {
     "synth__canonical_netlist__hash": {
-        "value": "9b1daddbf16520e983085be7f06a02bc2fc2e27a",
+        "value": "N/A",
         "compare": "==",
         "level": "warning"
     },
     "synth__netlist__hash": {
-        "value": "2d3fbf9f1b7357c0cadb1e193d984ae458d68fa8",
+        "value": "N/A",
         "compare": "==",
         "level": "warning"
     },
diff --git a/flow/designs/asap7/jpeg/config.mk b/flow/designs/asap7/jpeg/config.mk
@@ -15,3 +15,4 @@ export PLACE_DENSITY          = 0.75
 
 export TNS_END_PERCENT        = 100
 
+export SYNTH_USE_SYN = 1
diff --git a/flow/designs/asap7/jpeg/rules-base.json b/flow/designs/asap7/jpeg/rules-base.json
@@ -1,11 +1,11 @@
 {
     "synth__canonical_netlist__hash": {
-        "value": "b67ad398424800920e8203a11987e51a89b89070",
+        "value": "N/A",
         "compare": "==",
         "level": "warning"
     },
     "synth__netlist__hash": {
-        "value": "d045877b85c5a9e18d5284e8ad3a41dcbc5f3f11",
+        "value": "N/A",
         "compare": "==",
         "level": "warning"
     },
diff --git a/flow/designs/asap7/jpeg_lvt/config.mk b/flow/designs/asap7/jpeg_lvt/config.mk
@@ -18,3 +18,4 @@ export RECOVER_POWER          = 100
 
 export ASAP7_USE_VT           = LVT
 
+export SYNTH_USE_SYN = 1
diff --git a/flow/designs/asap7/jpeg_lvt/rules-base.json b/flow/designs/asap7/jpeg_lvt/rules-base.json
@@ -1,11 +1,11 @@
 {
     "synth__canonical_netlist__hash": {
-        "value": "c46712834957de101139bda123c9da786f05b392",
+        "value": "N/A",
         "compare": "==",
         "level": "warning"
     },
     "synth__netlist__hash": {
-        "value": "8c44353e931d56077e9f64190819c1fe10a05909",
+        "value": "N/A",
         "compare": "==",
         "level": "warning"
     },
@@ -90,11 +90,11 @@
         "compare": "<="
     },
     "finish__timing__setup__ws": {
-        "value": -30.0,
+        "value": -63.9,
         "compare": ">="
     },
     "finish__timing__setup__tns": {
-        "value": -303.0,
+        "value": -514.0,
         "compare": ">="
     },
     "finish__timing__hold__ws": {
diff --git a/flow/designs/ihp-sg13g2/aes/config.mk b/flow/designs/ihp-sg13g2/aes/config.mk
@@ -14,3 +14,5 @@ export TNS_END_PERCENT = 100
 export USE_FILL = 1
 
 export REMOVE_ABC_BUFFERS = 1
+
+export SYNTH_USE_SYN = 1
diff --git a/flow/designs/ihp-sg13g2/aes/rules-base.json b/flow/designs/ihp-sg13g2/aes/rules-base.json
@@ -1,11 +1,11 @@
 {
     "synth__canonical_netlist__hash": {
-        "value": "03f345300073bffe008c28ae418579c55a61a047",
+        "value": "N/A",
         "compare": "==",
         "level": "warning"
     },
     "synth__netlist__hash": {
-        "value": "9ed4fbb1904f7531317bb9162ca084ebe650f588",
+        "value": "N/A",
         "compare": "==",
         "level": "warning"
     },
diff --git a/flow/designs/ihp-sg13g2/gcd/config.mk b/flow/designs/ihp-sg13g2/gcd/config.mk
@@ -12,3 +12,4 @@ export TNS_END_PERCENT = 100
 
 export SWAP_ARITH_OPERATORS = 1
 export OPENROAD_HIERARCHICAL = 1
+export SYNTH_USE_SYN = 1
diff --git a/flow/designs/ihp-sg13g2/gcd/rules-base.json b/flow/designs/ihp-sg13g2/gcd/rules-base.json
@@ -1,11 +1,11 @@
 {
     "synth__canonical_netlist__hash": {
-        "value": "5a518ec61d78294e2e31f7564caba70a2e603a8b",
+        "value": "N/A",
         "compare": "==",
         "level": "warning"
     },
     "synth__netlist__hash": {
-        "value": "3fd7066325a56dedbd71ff32ffc04a42a6888885",
+        "value": "N/A",
         "compare": "==",
         "level": "warning"
     },
diff --git a/flow/designs/nangate45/dynamic_node/config.mk b/flow/designs/nangate45/dynamic_node/config.mk
@@ -15,3 +15,4 @@ export TNS_END_PERCENT = 100
 
 export SWAP_ARITH_OPERATORS = 1
 export OPENROAD_HIERARCHICAL = 1
+export SYNTH_USE_SYN = 1
diff --git a/flow/designs/nangate45/dynamic_node/rules-base.json b/flow/designs/nangate45/dynamic_node/rules-base.json
@@ -1,11 +1,11 @@
 {
     "synth__canonical_netlist__hash": {
-        "value": "2427a81238731cb7068ba9ca3da18ec2837ebf31",
+        "value": "N/A",
         "compare": "==",
         "level": "warning"
     },
     "synth__netlist__hash": {
-        "value": "4617e66bebd8728c158a91b4760b8d4ca0bb2114",
+        "value": "N/A",
         "compare": "==",
         "level": "warning"
     },
diff --git a/flow/scripts/synth_odb.tcl b/flow/scripts/synth_odb.tcl
@@ -1,4 +1,4 @@
-utl::set_metrics_stage "floorplan__{}"
+utl::set_metrics_stage "synth__{}"
 source $::env(SCRIPTS_DIR)/load.tcl
 erase_non_stage_variables synth
 load_design 1_2_yosys.v 1_2_yosys.sdc
@@ -24,6 +24,9 @@ source_step_tcl PRE SYNTH
 # asap7/jpeg_lvt, asap7/swerv_wrapper, nangate45/ariane133).
 log_cmd eliminate_dead_logic
 
+report_design_area
+report_design_area_metrics
+
 source_step_tcl POST SYNTH
 orfs_write_db $::env(RESULTS_DIR)/1_synth.odb
 # Canonicalize 1_synth.sdc. The original SDC_FILE provided by
diff --git a/flow/scripts/synth_syn.tcl b/flow/scripts/synth_syn.tcl
@@ -0,0 +1,76 @@
+utl::set_metrics_stage "synth__{}"
+source $::env(SCRIPTS_DIR)/load.tcl
+erase_non_stage_variables synth
+
+source_env_var_if_exists PLATFORM_TCL
+source $::env(SCRIPTS_DIR)/read_liberty.tcl
+
+read_lef $::env(TECH_LEF)
+read_lef $::env(SC_LEF)
+if { [env_var_exists_and_non_empty ADDITIONAL_LEFS] } {
+  foreach lef $::env(ADDITIONAL_LEFS) {
+    read_lef $lef
+  }
+}
+if { [env_var_exists_and_non_empty DONT_USE_CELLS] } {
+  set_dont_use $::env(DONT_USE_CELLS)
+}
+
+# Setup verilog include directories
+set vIdirsArgs ""
+if { [env_var_exists_and_non_empty VERILOG_INCLUDE_DIRS] } {
+  foreach dir $::env(VERILOG_INCLUDE_DIRS) {
+    lappend vIdirsArgs "-I$dir"
+  }
+  set vIdirsArgs [join $vIdirsArgs]
+}
+
+set elaborate_args [list \
+  -D SYNTHESIS --compat=vcs --ignore-assertions --no-implicit-memories --top $::env(DESIGN_NAME) \
+  {*}$vIdirsArgs {*}[env_var_or_empty VERILOG_DEFINES]]
+
+lappend elaborate_args {*}$::env(VERILOG_FILES)
+
+# Apply top-level parameters
+dict for {key value} [env_var_or_empty VERILOG_TOP_PARAMS] {
+  lappend elaborate_args -G "$key=$value"
+}
+
+# Apply module blackboxing based on module names as they appear
+# in the input, that is before any module name mangling done
+# by elaboration and synthesis
+if { [env_var_exists_and_non_empty SYNTH_BLACKBOXES] } {
+  foreach m $::env(SYNTH_BLACKBOXES) {
+    lappend elaborate_args --blackboxed-module "$m"
+  }
+}
+
+lappend elaborate_args {*}$::env(SYNTH_SLANG_ARGS)
+
+# If the sources are solely .v files, enable Verilog compatibility
+set has_non_v_files false
+foreach fn $::env(VERILOG_FILES) {
+  if { [file extension [string trim $fn]] != ".v" } {
+    set has_non_v_files true
+  }
+}
+if { !$has_non_v_files } {
+  lappend elaborate_args --std=1364-2005
+}
+
+sv_elaborate {*}$elaborate_args
+syn::stats
+
+synthesize
+
+read_sdc $::env(SDC_FILE)
+repair_design -pre_placement
+
+report_metrics 1 "synth" false false
+
+orfs_write_db $::env(RESULTS_DIR)/1_synth.odb
+# Canonicalize 1_synth.sdc. The original SDC_FILE provided by
+# the user could have dependencies, such as sourcing util.tcl,
+# which are read in here and a canonicalized version is written
+# out by OpenSTA that has no dependencies.
+orfs_write_sdc $::env(RESULTS_DIR)/1_synth.sdc
diff --git a/flow/scripts/variables.json b/flow/scripts/variables.json
diff --git a/flow/scripts/variables.yaml b/flow/scripts/variables.yaml
@@ -115,6 +115,7 @@ SKIP_REPORT_METRICS:
     If set to 1, then metrics, report_metrics does nothing. Useful to speed up
     builds.
   stages:
+    - synth
     - floorplan
     - place
     - cts
@@ -180,6 +181,14 @@ SYNTH_HIERARCHICAL:
   stages:
     - synth
   default: 0
+SYNTH_USE_SYN:
+  description: >
+    If set to 1, run synthesis using the "syn" tool built into OpenROAD
+    (the synth_syn.tcl flow) instead of the default Yosys-based flow.
+    Defaults to 0 (Yosys flow).
+  stages:
+    - synth
+  default: 0
 SYNTH_MEMORY_MAX_BITS:
   description: >
     Maximum number of bits for memory synthesis.
diff --git a/flow/util/genMetrics.py b/flow/util/genMetrics.py

Original file line number	Diff line number	Diff line change
`@@ -18,4 +18,4 @@ export ASAP7_USE_VT = LVT`
`18`	`18`
`19`	`19`	`export RECOVER_POWER = 100`
`20`	`20`
`21`		`-`
	`21`	`+export SYNTH_USE_SYN = 1`
Original file line number	Diff line number	Diff line change
`@@ -16,3 +16,4 @@ export PLACE_DENSITY = 0.35`
`16`	`16`	`# few last gasp iterations`
`17`	`17`	`export SKIP_LAST_GASP ?= 1`
`18`	`18`
	`19`	`+export SYNTH_USE_SYN = 1`
Original file line number	Diff line number	Diff line change
`@@ -15,3 +15,4 @@ export PLACE_DENSITY = 0.75`
`15`	`15`
`16`	`16`	`export TNS_END_PERCENT = 100`
`17`	`17`
	`18`	`+export SYNTH_USE_SYN = 1`