Add find_vars method to VHDL syntax objects

Finds set of read and written variables. For use in
post-processing the syntax tree for cleanup.

tgt-vhdl/vhdl_syntax.cc

@@ -255,6 +255,17 @@ void stmt_container::move_stmts_from(stmt_container *other)
    other->stmts_.clear();
 }
 
+void stmt_container::find_vars(vhdl_var_set_t& read,
+                               vhdl_var_set_t& write)
+{
+   // Iterate over each sub-statement and find all its
+   // read/written variables
+
+   for (stmt_list_t::const_iterator it = stmts_.begin();
+        it != stmts_.end(); ++it)
+      (*it)->find_vars(read, write); 
+}
+
 void stmt_container::emit(std::ostream &of, int level, bool newline) const
 {
    emit_children<vhdl_seq_stmt>(of, stmts_, level, "", newline);
@@ -347,6 +358,13 @@ vhdl_wait_stmt::~vhdl_wait_stmt()
 
 }
 
+void vhdl_wait_stmt::find_vars(vhdl_var_set_t& read,
+                               vhdl_var_set_t& write)
+{
+   if (expr_)
+      expr_->find_vars(read);
+}
+
 void vhdl_wait_stmt::emit(std::ostream &of, int level) const
 {
    of << "wait";
@@ -497,6 +515,13 @@ vhdl_expr_list::~vhdl_expr_list()
 
 }
 
+void vhdl_expr_list::find_vars(vhdl_var_set_t& read)
+{
+   for (list<vhdl_expr*>::const_iterator it = exprs_.begin();
+        it != exprs_.end(); ++it)
+      (*it)->find_vars(read);
+}
+
 void vhdl_expr_list::emit(std::ostream &of, int level) const
 {
    of << "(";
@@ -520,6 +545,12 @@ void vhdl_pcall_stmt::emit(std::ostream &of, int level) const
    of << ";";
 }
 
+void vhdl_pcall_stmt::find_vars(vhdl_var_set_t& read,
+                                vhdl_var_set_t& write)
+{
+   exprs_.find_vars(read);
+}
+
 vhdl_var_ref::~vhdl_var_ref()
 {
 
@@ -546,6 +577,11 @@ void vhdl_var_ref::set_slice(vhdl_expr *s, int w)
    }
 }
 
+void vhdl_var_ref::find_vars(vhdl_var_set_t& read)
+{
+   read.insert(this);
+}
+
 void vhdl_var_ref::emit(std::ostream &of, int level) const
 {
    of << name_;
@@ -575,6 +611,11 @@ void vhdl_null_stmt::emit(std::ostream &of, int level) const
    emit_comment(of, level, true);
 }
 
+void vhdl_fcall::find_vars(vhdl_var_set_t& read)
+{
+   exprs_.find_vars(read);
+}
+
 void vhdl_fcall::emit(std::ostream &of, int level) const
 {
    of << name_;
@@ -586,6 +627,13 @@ vhdl_abstract_assign_stmt::~vhdl_abstract_assign_stmt()
 
 }
 
+void vhdl_abstract_assign_stmt::find_vars(vhdl_var_set_t& read,
+                                          vhdl_var_set_t& write)
+{
+   write.insert(lhs_);
+   rhs_->find_vars(read);
+}
+
 void vhdl_nbassign_stmt::emit(std::ostream &of, int level) const
 {
    lhs_->emit(of, level);
@@ -767,6 +815,21 @@ void vhdl_if_stmt::emit(std::ostream &of, int level) const
    of << "end if;";
 }
 
+void vhdl_if_stmt::find_vars(vhdl_var_set_t& read,
+                             vhdl_var_set_t& write)
+{
+   test_->find_vars(read);
+
+   then_part_.find_vars(read, write);
+   else_part_.find_vars(read, write);
+
+   for (list<elsif>::const_iterator it = elsif_parts_.begin();
+        it != elsif_parts_.end(); ++it) {
+      (*it).test->find_vars(read);
+      (*it).container->find_vars(read, write);
+   }      
+}
+
 int vhdl_expr::paren_levels(0);
 
 void vhdl_expr::open_parens(std::ostream& of)
@@ -788,6 +851,11 @@ vhdl_unaryop_expr::~vhdl_unaryop_expr()
 
 }
 
+void vhdl_unaryop_expr::find_vars(vhdl_var_set_t& read)
+{
+   operand_->find_vars(read);
+}
+
 void vhdl_unaryop_expr::emit(std::ostream &of, int level) const
 {
    open_parens(of);
@@ -823,6 +891,13 @@ void vhdl_binop_expr::add_expr(vhdl_expr *e)
    operands_.push_back(e);
 }
 
+void vhdl_binop_expr::find_vars(vhdl_var_set_t& read)
+{
+   for (list<vhdl_expr*>::const_iterator it = operands_.begin();
+       it != operands_.end(); ++it)
+      (*it)->find_vars(read);      
+}
+
 void vhdl_binop_expr::emit(std::ostream &of, int level) const
 {
    open_parens(of);
@@ -896,6 +971,18 @@ vhdl_case_stmt::~vhdl_case_stmt()
 
 }
 
+void vhdl_case_stmt::find_vars(vhdl_var_set_t& read,
+                               vhdl_var_set_t& write)
+{
+   test_->find_vars(read);
+
+   for (case_branch_list_t::const_iterator it = branches_.begin();
+        it != branches_.end(); ++it) {
+      (*it)->when_->find_vars(read);
+      (*it)->stmts_.find_vars(read, write);
+   }
+}
+
 void vhdl_case_stmt::emit(std::ostream &of, int level) const
 {
    of << "case ";
@@ -921,6 +1008,14 @@ vhdl_while_stmt::~vhdl_while_stmt()
 
 }
 
+void vhdl_while_stmt::find_vars(vhdl_var_set_t& read,
+                                vhdl_var_set_t& write)
+{
+   test_->find_vars(read);
+
+   vhdl_loop_stmt::find_vars(read, write);
+}
+
 void vhdl_while_stmt::emit(std::ostream &of, int level) const
 {
    of << "while ";
@@ -929,6 +1024,12 @@ void vhdl_while_stmt::emit(std::ostream &of, int level) const
    vhdl_loop_stmt::emit(of, level);
 }
 
+void vhdl_loop_stmt::find_vars(vhdl_var_set_t& read,
+                               vhdl_var_set_t& write)
+{
+   stmts_.find_vars(read, write);
+}
+
 void vhdl_loop_stmt::emit(std::ostream &of, int level) const
 {
    of << "loop";
@@ -941,6 +1042,16 @@ vhdl_for_stmt::~vhdl_for_stmt()
 
 }
 
+
+void vhdl_for_stmt::find_vars(vhdl_var_set_t& read,
+                              vhdl_var_set_t& write)
+{
+   from_->find_vars(read);
+   to_->find_vars(write);
+
+   vhdl_loop_stmt::find_vars(read, write);
+}
+
 void vhdl_for_stmt::emit(std::ostream &of, int level) const
 {
    of << "for " << lname_ << " in ";

tgt-vhdl/vhdl_syntax.hh

@@ -22,6 +22,7 @@
 #define INC_VHDL_SYNTAX_HH
 
 #include <inttypes.h>
+#include <set>
 #include <cassert>
 #include "vhdl_element.hh"
 #include "vhdl_type.hh"
@@ -31,6 +32,9 @@ using namespace std;
 class vhdl_scope;
 class vhdl_entity;
 class vhdl_arch;
+class vhdl_var_ref;
+
+typedef set<vhdl_var_ref*> vhdl_var_set_t;
 
 class vhdl_expr : public vhdl_element {
 public:
@@ -48,6 +52,7 @@ public:
    virtual vhdl_expr *to_std_logic();
    virtual vhdl_expr *to_std_ulogic();
    virtual vhdl_expr *to_vector(vhdl_type_name_t name, int w);
+   virtual void find_vars(vhdl_var_set_t& read) const {}
    
 protected:
    static void open_parens(ostream& of);
@@ -73,13 +78,13 @@ public:
    const std::string &get_name() const { return name_; }
    void set_name(const std::string &name) { name_ = name; }
    void set_slice(vhdl_expr *s, int w=0);
+   void find_vars(vhdl_var_set_t& read);
 private:
    std::string name_;
    vhdl_expr *slice_;
    unsigned slice_width_;
 };
 
-
 enum vhdl_binop_t {
    VHDL_BINOP_AND = 0,
    VHDL_BINOP_OR,
@@ -121,6 +126,7 @@ public:
 
    void add_expr(vhdl_expr *e);
    void emit(std::ostream &of, int level) const;
+   void find_vars(vhdl_var_set_t& read);
 private:
    std::list<vhdl_expr*> operands_;
    vhdl_binop_t op_;
@@ -140,6 +146,7 @@ public:
    ~vhdl_unaryop_expr();
 
    void emit(std::ostream &of, int level) const;
+   void find_vars(vhdl_var_set_t& read);
 private:
    vhdl_unaryop_t op_;
    vhdl_expr *operand_;
@@ -252,6 +259,7 @@ public:
    void emit(std::ostream &of, int level) const;
    bool empty() const { return exprs_.empty(); }
    void add_expr(vhdl_expr *e);
+   void find_vars(vhdl_var_set_t& read);
 private:
    std::list<vhdl_expr*> exprs_;
 };
@@ -268,6 +276,7 @@ public:
 
    void add_expr(vhdl_expr *e) { exprs_.add_expr(e); }
    void emit(std::ostream &of, int level) const;
+   void find_vars(vhdl_var_set_t& read);
 private:
    std::string name_;
    vhdl_expr_list exprs_;
@@ -338,6 +347,12 @@ private:
 class vhdl_seq_stmt : public vhdl_element {
 public:
    virtual ~vhdl_seq_stmt() {}
+
+   // Find all the variables that are read or written in the
+   // expressions within this statement
+   // This is used to clean up the VHDL output
+   virtual void find_vars(vhdl_var_set_t& read,
+                          vhdl_var_set_t& write) = 0;
 };
 
 
@@ -353,6 +368,7 @@ public:
    void move_stmts_from(stmt_container *other);
    void emit(std::ostream &of, int level, bool newline=true) const;
    bool empty() const { return stmts_.empty(); }
+   void find_vars(vhdl_var_set_t& read, vhdl_var_set_t& write);
 
    typedef std::list<vhdl_seq_stmt*> stmt_list_t;
    stmt_list_t &get_stmts() { return stmts_; }
@@ -371,6 +387,7 @@ public:
    virtual ~vhdl_abstract_assign_stmt();
 
    void set_after(vhdl_expr *after) { after_ = after; }
+   void find_vars(vhdl_var_set_t& read, vhdl_var_set_t& write);
 protected:
    vhdl_var_ref *lhs_;
    vhdl_expr *rhs_, *after_;
@@ -421,6 +438,7 @@ public:
    void emit(std::ostream &of, int level) const;
    void add_sensitivity(const std::string &s) { sensitivity_.push_back(s); }
    vhdl_wait_type_t get_type() const { return type_; }
+   void find_vars(vhdl_var_set_t& read, vhdl_var_set_t& write);
 private:
    vhdl_wait_type_t type_;
    vhdl_expr *expr_;
@@ -431,6 +449,7 @@ private:
 class vhdl_null_stmt : public vhdl_seq_stmt {
 public:
    void emit(std::ostream &of, int level) const;
+   void find_vars(vhdl_var_set_t& read, vhdl_var_set_t& write) {}
 };
 
 
@@ -440,6 +459,7 @@ public:
       : reason_(reason) {}
 
    void emit(std::ostream &of, int level) const;
+   void find_vars(vhdl_var_set_t& read, vhdl_var_set_t& write) {}
 private:
    std::string reason_;
 };
@@ -454,6 +474,7 @@ public:
    stmt_container *get_else_container() { return &else_part_; }
    stmt_container *add_elsif(vhdl_expr *test);
    void emit(std::ostream &of, int level) const;
+   void find_vars(vhdl_var_set_t& read, vhdl_var_set_t& write);
 private:
    struct elsif {
       vhdl_expr *test;
@@ -471,6 +492,7 @@ private:
  * expression part and a statement container.
  */
 class vhdl_case_branch : public vhdl_element {
+   friend class vhdl_case_stmt;
 public:
    vhdl_case_branch(vhdl_expr *when) : when_(when) {}
    ~vhdl_case_branch();
@@ -491,6 +513,7 @@ public:
 
    void add_branch(vhdl_case_branch *b) { branches_.push_back(b); }
    void emit(std::ostream &of, int level) const;
+   void find_vars(vhdl_var_set_t& read, vhdl_var_set_t& write);
 private:
    vhdl_expr *test_;
    case_branch_list_t branches_;
@@ -503,6 +526,8 @@ public:
 
    stmt_container *get_container() { return &stmts_; }
    void emit(std::ostream &of, int level) const;
+   virtual void find_vars(vhdl_var_set_t& read,
+                          vhdl_var_set_t& write);
 private:
    stmt_container stmts_;
 };
@@ -514,6 +539,7 @@ public:
    ~vhdl_while_stmt();
 
    void emit(std::ostream &of, int level) const;
+   void find_vars(vhdl_var_set_t& read, vhdl_var_set_t& write);
 private:
    vhdl_expr *test_;
 };
@@ -526,6 +552,7 @@ public:
    ~vhdl_for_stmt();
 
    void emit(std::ostream &of, int level) const;
+   void find_vars(vhdl_var_set_t& read, vhdl_var_set_t& write);
 private:
    const char *lname_;
    vhdl_expr *from_, *to_;
@@ -542,6 +569,7 @@ public:
 
    void emit(std::ostream &of, int level) const;
    void add_expr(vhdl_expr *e) { exprs_.add_expr(e); }
+   void find_vars(vhdl_var_set_t& read, vhdl_var_set_t& write);
 private:
    std::string name_;
    vhdl_expr_list exprs_;