BST: skip visiting the body of BST_ClassDef and BST_FunctionDef nodes

now that the FlattenVisitor is gone nobody uses this anymore

src/analysis/function_analysis.cpp

@@ -70,9 +70,7 @@ private:
 
 public:
     LivenessBBVisitor(LivenessAnalysis* analysis)
-        : NoopBSTVisitor(true /* skip child CFG nodes */),
-          statuses(analysis->cfg->getVRegInfo().getTotalNumOfVRegs()),
-          analysis(analysis) {}
+        : statuses(analysis->cfg->getVRegInfo().getTotalNumOfVRegs()), analysis(analysis) {}
 
     bool firstIsUse(int vreg) const { return getStatusFirst(vreg) == Status::USED; }
     bool firstIsDef(int vreg) const { return getStatusFirst(vreg) == Status::DEFINED; }
@@ -212,7 +210,7 @@ private:
     }
 
 public:
-    DefinednessVisitor(Map& state) : NoopBSTVisitor(true /* skip child CFG nodes */), state(state) {}
+    DefinednessVisitor(Map& state) : state(state) {}
     bool visit_vreg(int* vreg, bool is_dest) override {
         if (*vreg < 0)
             return false;

src/codegen/irgen.cpp

@@ -344,8 +344,7 @@ private:
     SymbolTable* sym_table;
     bool created_new_sym_table;
 
-    SymTableDstVRegDeleter(SymbolTable* sym_table)
-        : NoopBSTVisitor(true /* skip child CFG nodes */), sym_table(sym_table), created_new_sym_table(false) {}
+    SymTableDstVRegDeleter(SymbolTable* sym_table) : sym_table(sym_table), created_new_sym_table(false) {}
 
 protected:
     bool visit_vreg(int* vreg, bool is_dst = false) override {

src/core/bst.cpp

@@ -43,12 +43,6 @@ template <class T> static void visitVector(const std::vector<T*>& vec, BSTVisito
     }
 }
 
-static void visitCFG(CFG* cfg, BSTVisitor* v) {
-    for (auto bb : cfg->blocks)
-        for (auto e : bb->body)
-            e->accept(v);
-}
-
 void BST_Assert::accept(BSTVisitor* v) {
     bool skip = v->visit_assert(this);
     if (skip)
@@ -180,8 +174,7 @@ void BST_ClassDef::accept(BSTVisitor* v) {
         v->visit_vreg(&decorator[i]);
     }
 
-    if (!v->skip_visit_child_cfg)
-        visitCFG(this->code->source->cfg, v);
+    // we dont't visit the body
 }
 
 void BST_ClassDef::accept_stmt(StmtVisitor* v) {
@@ -272,8 +265,7 @@ void BST_FunctionDef::accept(BSTVisitor* v) {
     for (int i = 0; i < num_decorator + num_defaults; ++i) {
         v->visit_vreg(&elts[i]);
     }
-    if (!v->skip_visit_child_cfg)
-        visitCFG(code->source->cfg, v);
+    // we dont't visit the body
 }
 
 void BST_FunctionDef::accept_stmt(StmtVisitor* v) {

src/core/bst.h

@@ -725,9 +725,7 @@ template <typename T> T* bst_cast(BST_stmt* node) {
 
 class BSTVisitor {
 public:
-    const bool skip_visit_child_cfg;
-    // if skip_visit_child_cfg is set function and class defs will not visit their body nodes.
-    BSTVisitor(bool skip_visit_child_cfg) : skip_visit_child_cfg(skip_visit_child_cfg) {}
+    BSTVisitor() {}
     virtual ~BSTVisitor() {}
 
     // pseudo
@@ -790,7 +788,7 @@ public:
 class NoopBSTVisitor : public BSTVisitor {
 protected:
 public:
-    NoopBSTVisitor(bool skip_visit_child_cfg) : BSTVisitor(skip_visit_child_cfg) {}
+    NoopBSTVisitor() {}
     virtual ~NoopBSTVisitor() {}
 
     virtual bool visit_assert(BST_Assert* node) override { return false; }
@@ -919,7 +917,7 @@ private:
 
 public:
     PrintVisitor(const CodeConstants& code_constants, int indent, llvm::raw_ostream& stream)
-        : BSTVisitor(false /* visit child CFG */), stream(stream), code_constants(code_constants), indent(indent) {}
+        : stream(stream), code_constants(code_constants), indent(indent) {}
     virtual ~PrintVisitor() {}
     void flush() { stream.flush(); }
 

src/core/cfg.cpp

@@ -2917,7 +2917,7 @@ public:
     enum Step { TrackBlockUsage = 0, UserVisible, CrossBlock, SingleBlockUse } step;
 
     AssignVRegsVisitor(llvm::DenseMap<int*, InternedString>& id_vreg)
-        : NoopBSTVisitor(true /* skip child CFG nodes */), current_block(0), next_vreg(0), id_vreg(id_vreg) {}
+        : current_block(0), next_vreg(0), id_vreg(id_vreg) {}
 
     bool visit_vreg(int* vreg, bool is_dst = false) override {
         if (is_dst) {