rmp: Simulated annealing

src/rmp/BUILD

@@ -14,10 +14,14 @@ cc_library(
     name = "rmp",
     srcs = [
         "src/Restructure.cpp",
+        "src/annealing_strategy.cpp",
+        "src/annealing_strategy.h",
         "src/delay_optimization_strategy.cpp",
         "src/delay_optimization_strategy.h",
         "src/logic_optimization_strategy.h",
         "src/resynthesis_strategy.h",
+        "src/utils.cpp",
+        "src/utils.h",
         "src/zero_slack_strategy.cpp",
         "src/zero_slack_strategy.h",
     ],

src/rmp/README.md

@@ -66,6 +66,36 @@ resynth
 | ----- | ----- |
 | `-corner` | Process corner to use. |
 
+### Resynth with simulated annealing
+
+Resynthesize parts of the design with an ABC script found via simulated annealing.
+The script is a series of operations on ABC's internal AIG data structure.
+A neighboring solution is a script with one operation added, removed, or two operations swapped.
+The optimization function is defined as the worst slack.
+
+```tcl
+resynth_annealing
+    [-corner corner]
+    [-slack_threshold slack_threshold]
+    [-seed seed]
+    [-temp temp]
+    [-iters iters]
+    [-revert_after revert_after]
+    [-initial_ops initial_ops]
+```
+
+#### Options
+
+| Switch Name | Description |
+| ----- | ----- |
+| `-corner` | Process corner to use. |
+| `-slack_threshold` | Specifies a (setup) timing slack value below which timing paths need to be analyzed for restructuring. The default value is `0`. |
+| `-seed` | Seed to use for randomness in simulated annealing. |
+| `-temp` | Initial temperature for simulated annealing. The default is the required arrival time on the worst slack endpoint. |
+| `-iters` | Number of iterations to run simulated annealing for. |
+| `-revert_after` | After the given number of iterations that worsen slack, revert to best found solution. |
+| `-initial_ops` | Size of the initial random solution (number of commands in the script for ABC). |
+
 ## Example scripts
 
 Example scripts on running `rmp` for a sample design of `gcd` as follows:

src/rmp/include/rmp/Restructure.h

@@ -66,12 +66,22 @@ class Restructure
 
   void reset();
   void resynth(sta::Corner* corner);
+  void resynthAnnealing(sta::Corner* corner);
   void run(char* liberty_file_name,
            float slack_threshold,
            unsigned max_depth,
            char* workdir_name,
            char* abc_logfile);
 
+  void setAnnealingSeed(uint64_t seed) { annealing_seed_ = seed; }
+  void setAnnealingTemp(float temp) { annealing_temp_ = temp; }
+  void setAnnealingIters(unsigned iters) { annealing_iters_ = iters; }
+  void setAnnealingRevertAfter(unsigned revert_after)
+  {
+    annealing_revert_after_ = revert_after;
+  }
+  void setAnnealingInitialOps(unsigned ops) { annealing_init_ops_ = ops; }
+  void setSlackThreshold(sta::Slack thresh) { slack_threshold_ = thresh; }
   void setMode(const char* mode_name);
   void setTieLoPort(sta::LibertyPort* loport);
   void setTieHiPort(sta::LibertyPort* hiport);
@@ -106,6 +116,14 @@ class Restructure
   est::EstimateParasitics* estimate_parasitics_;
   odb::dbBlock* block_ = nullptr;
 
+  // Annealing
+  std::optional<uint64_t> annealing_seed_;
+  std::optional<float> annealing_temp_;
+  unsigned annealing_iters_ = 100;
+  std::optional<unsigned> annealing_revert_after_;
+  unsigned annealing_init_ops_ = 10;
+  sta::Slack slack_threshold_ = 0;
+
   std::string input_blif_file_name_;
   std::string output_blif_file_name_;
   std::vector<std::string> lib_file_names_;

src/rmp/src/CMakeLists.txt

@@ -14,10 +14,17 @@ swig_lib(NAME      rmp
 
 add_library(rmp_lib
     Restructure.cpp
+    annealing_strategy.cpp
     delay_optimization_strategy.cpp
+    utils.cpp
     zero_slack_strategy.cpp
 )
 
+# For ABC headers
+set_source_files_properties(annealing_strategy.cpp
+  PROPERTIES COMPILE_FLAGS "-Wno-error=redundant-decls -Wno-error=unused-variable -Wno-error=unused-but-set-variable"
+)
+
 target_sources(rmp
   PRIVATE
     MakeRestructure.cpp
@@ -42,7 +49,7 @@ target_include_directories(rmp_lib
   PUBLIC
     ../include
 )
-  
+
 target_link_libraries(rmp_lib
   PUBLIC
     odb
@@ -58,7 +65,7 @@ target_link_libraries(rmp
   PRIVATE
     rmp_lib
 )
- 
+
 if (Python3_FOUND AND BUILD_PYTHON)
   swig_lib(NAME          rmp_py
            NAMESPACE     rmp

src/rmp/src/Restructure.cpp

@@ -20,6 +20,7 @@
 #include <utility>
 #include <vector>
 
+#include "annealing_strategy.h"
 #include "base/abc/abc.h"
 #include "base/main/abcapis.h"
 #include "cut/abc_init.h"
@@ -87,6 +88,19 @@ void Restructure::resynth(sta::Corner* corner)
       open_sta_, name_generator_, resizer_, logger_);
 }
 
+void Restructure::resynthAnnealing(sta::Corner* corner)
+{
+  AnnealingStrategy annealing_strategy(corner,
+                                       slack_threshold_,
+                                       annealing_seed_,
+                                       annealing_temp_,
+                                       annealing_iters_,
+                                       annealing_revert_after_,
+                                       annealing_init_ops_);
+  annealing_strategy.OptimizeDesign(
+      open_sta_, name_generator_, resizer_, logger_);
+}
+
 void Restructure::run(char* liberty_file_name,
                       float slack_threshold,
                       unsigned max_depth,