finish preparations for coloring

include/opt/cfg.h

@@ -150,3 +150,15 @@ bool GetCollectionsIsSame(const Container &a, const Container &b, Compare comp =
 }
 
 CFGType BuildCFGForFunction(const std::shared_ptr<FunctionDefItem> &func);
+
+// RISC-V calling convention compatible
+const static std::vector<std::string> held_tmp_regs = {"x28", "x29", "x30", "x31"};
+const static std::string zero = "x0", sp = "x2", ra = "x1", fp = "x8";
+const static std::vector<std::string> callee_saved_regs = {"x3",  "x4",  "x9",  "x18", "x19", "x20", "x21",
+                                                           "x22", "x23", "x24", "x25", "x26", "x27"};
+const static std::vector<std::string> caller_saved_regs = {"x5",  "x6",  "x7",  "x10", "x11", "x12",
+                                                           "x13", "x14", "x15", "x16", "x17"};
+const static std::vector<std::string> arg_regs = {"x10", "x11", "x12", "x13", "x14", "x15", "x16", "x17"};
+const static std::vector<std::string> allocating_regs = {"x3",  "x4",  "x9",  "x18", "x19", "x20", "x21", "x22",
+                                                         "x23", "x24", "x25", "x26", "x27", "x5",  "x6",  "x7",
+                                                         "x10", "x11", "x12", "x13", "x14", "x15", "x16", "x17"};

include/opt/confgraph.h

@@ -3,19 +3,32 @@
 #include "cfg.h"
 class ConfGraphNode {
  public:
-  std::string var_name;
+  const static size_t kInf = (std::numeric_limits<size_t>::max()) >> 2;
+  std::vector<size_t> var_ids;
   size_t color;
-  bool is_move_related;
+  size_t degree;
-  bool move_related_but_frozen;
   bool is_binded_with_physical_reg;
-  std::vector<ConfGraphNode *> neighbors;
+  std::list<ConfGraphNode *> neighbors;
-  ConfGraphNode(std::string var_name) : var_name(var_name) {}
+  std::list<opt::MoveInstruct *> move_neighbors;
+  ConfGraphNode() = default;
 };
 class ConfGraph {
  public:
-  std::unordered_map<std::string, ConfGraphNode *> name_to_node;
+  // available after construction
+  std::unordered_map<size_t, ConfGraphNode *> id_to_node;
   std::vector<std::shared_ptr<ConfGraphNode>> nodes;
+  std::unordered_map<ConfGraphNode *, std::unordered_map<ConfGraphNode *, std::list<ConfGraphNode *>::iterator>>
+      adj_table;
+
+  // available during coloring
+  std::vector<ConfGraphNode *> stack;
+  std::vector<ConfGraphNode *> actual_spills;
+  std::unordered_set<ConfGraphNode *> low_degree_and_not_move_related;
+  std::unordered_set<ConfGraphNode *> low_degree_and_move_related;
+  std::unordered_set<ConfGraphNode *> high_degree_nodes;
+  std::unordered_set<opt::MoveInstruct *> pending_moves;
+  std::unordered_set<opt::MoveInstruct *> potential_moves;
 };
 
 ConfGraph BuildConfGraph(CFGType &cfg);
-bool TryColoring(std::shared_ptr<FunctionDefItem> src, CFGType &cfg, ConfGraph& confgraph);
+bool ConductColoring(std::shared_ptr<FunctionDefItem> src, CFGType &cfg, ConfGraph &confgraph);

src/opt/confgraph.cpp

@@ -1,6 +1,80 @@
 #include "confgraph.h"
+#include <cstdint>
+#include <set>
+#include <string>
 #include <unordered_map>
+#include <unordered_set>
 #include "cfg.h"
+ConfGraph BuildConfGraph(CFGType &cfg) {
+  std::unordered_map<ConfGraphNode *, std::unordered_set<ConfGraphNode *>> edges;
+  ConfGraph res;
+  for (size_t id = 0; id < cfg.id_to_var.size(); id++) {
+    auto node = std::make_shared<ConfGraphNode>();
+    node->var_ids.push_back(id);
+    res.id_to_node[id] = node.get();
+    res.nodes.push_back(node);
+    node->is_binded_with_physical_reg = false;
+  }
+  for (auto cfg_node : cfg.nodes) {
+    for (const auto &[act, out_active] : cfg_node->action_out_active_vars) {
+      const auto &def_vars = cfg_node->action_def_vars[act];
+      for (auto def_var : def_vars) {
+        for (auto out_var : out_active) {
+          edges[res.id_to_node[def_var]].insert(res.id_to_node[out_var]);
+          edges[res.id_to_node[out_var]].insert(res.id_to_node[def_var]);
+        }
+      }
+    }
+  }
+  for (const auto &[u, neighbors] : edges) {
+    for (auto v : neighbors) {
+      u->neighbors.push_back(v);
+      res.adj_table[u][v] = std::prev(u->neighbors.end());
+    }
+    u->neighbors.sort();
+  }
+  for (auto node : res.nodes) {
+    node->degree = node->neighbors.size();
+  }
+  for (auto reg : allocating_regs) {
+    size_t reg_id = cfg.var_to_id["%reg." + reg];
+    res.id_to_node[reg_id]->is_binded_with_physical_reg = true;
+    res.id_to_node[reg_id]->color = std::stoi(reg.substr(1));
+    res.id_to_node[reg_id]->degree = ConfGraphNode::kInf;
+  }
+  return res;
+}
+const static size_t kMaxRegs = allocating_regs.size();
+void InitializeBeforeColoring(std::shared_ptr<FunctionDefItem> src, CFGType &cfg, ConfGraph &confgraph) {
+  confgraph.stack.clear();
+  confgraph.actual_spills.clear();
 
-ConfGraph BuildConfGraph(CFGType &cfg) { ; }
+  confgraph.low_degree_and_not_move_related.clear();
-bool TryColoring(std::shared_ptr<FunctionDefItem> src, CFGType &cfg, ConfGraph& confgraph) { return false; }
+  confgraph.low_degree_and_move_related.clear();
+  confgraph.high_degree_nodes.clear();  // note that physical registers are not included in this set
+
+  confgraph.pending_moves.clear();
+  confgraph.potential_moves.clear();
+}
+bool ConductColoring(std::shared_ptr<FunctionDefItem> src, CFGType &cfg, ConfGraph &confgraph) {
+  InitializeBeforeColoring(src, cfg, confgraph);
+  do {
+    if (confgraph.low_degree_and_not_move_related.size() > 0) {
+      // simplify
+    } else if (confgraph.pending_moves.size() > 0) {
+      // coalesce
+    } else if (confgraph.low_degree_and_move_related.size() > 0) {
+      // freeze
+    } else if (confgraph.high_degree_nodes.size() > 0) {
+      // potential spill
+    }
+  } while (confgraph.low_degree_and_not_move_related.size() > 0 || confgraph.pending_moves.size() > 0 ||
+           confgraph.low_degree_and_move_related.size() > 0 || confgraph.high_degree_nodes.size() > 0);
+  // select and spill
+  if (confgraph.actual_spills.size() > 0) {
+    std::cerr << "spilled " << confgraph.actual_spills.size() << " nodes" << std::endl;
+    // allocate memory for spilled nodes
+    return true;
+  }
+  return false;
+}

src/opt/regalloc.cpp

@@ -6,14 +6,6 @@
 #include "phieliminate.h"
 #include "tools.h"
 
-// RISC-V calling convention compatible
-static std::vector<std::string> held_tmp_regs = {"x28", "x29", "x30", "x31"};
-static std::vector<std::string> callee_saved_regs = {"x3",  "x4",  "x9",  "x18", "x19", "x20", "x21",
-                                                     "x22", "x23", "x24", "x25", "x26", "x27"};
-static std::vector<std::string> caller_saved_regs = {"x5",  "x6",  "x7",  "x10", "x11", "x12",
-                                                     "x13", "x14", "x15", "x16", "x17"};
-static std::vector<std::string> arg_regs = {"x10", "x11", "x12", "x13", "x14", "x15", "x16", "x17"};
-static std::string zero = "x0", sp = "x2", ra = "x1", fp = "x8";
 void EnforcePhysicalRegs(CFGType &cfg) {
   using namespace opt;
   // process callee side
@@ -128,14 +120,16 @@ void EnforcePhysicalRegs(CFGType &cfg) {
   }
 }
 void ConductRegAllocForFunction(std::shared_ptr<FunctionDefItem> func) {
+  std::cerr << "processing function " << func->func_name_raw << std::endl;
   CFGType cfg;
   ConfGraph confgraph;
+  cfg = BuildCFGForFunction(func);
+  EnforcePhysicalRegs(cfg);
   do {
     cfg = BuildCFGForFunction(func);
-    EnforcePhysicalRegs(cfg);
     LiveAnalysis(cfg);
     confgraph = BuildConfGraph(cfg);
-  } while (TryColoring(func, cfg, confgraph));
+  } while (ConductColoring(func, cfg, confgraph));
 }
 
 std::shared_ptr<ModuleItem> RegAlloc(std::shared_ptr<ModuleItem> src) {