Elaborate foreach loops as synthetic for loops.

Create an implicit scope to hold the index variable, and
generate a for loop to perform the functionality of the
foreach.

Author: steveicarus

Statement.cc

@@ -336,6 +336,16 @@ PForce::~PForce()
       delete expr_;
 }
 
+PForeach::PForeach(perm_string av, perm_string ix, Statement*s)
+: array_var_(av), index_var_(ix), statement_(s)
+{
+}
+
+PForeach::~PForeach()
+{
+      delete statement_;
+}
+
 PForever::PForever(Statement*s)
 : statement_(s)
 {

Statement.h

@@ -443,6 +443,22 @@ class PForce  : public Statement {
       PExpr*expr_;
 };
 
+class PForeach : public Statement {
+    public:
+      explicit PForeach(perm_string var, perm_string ix, Statement*stmt);
+      ~PForeach();
+
+      virtual NetProc* elaborate(Design*des, NetScope*scope) const;
+      virtual void elaborate_scope(Design*des, NetScope*scope) const;
+      virtual void elaborate_sig(Design*des, NetScope*scope) const;
+      virtual void dump(ostream&out, unsigned ind) const;
+
+    private:
+      perm_string array_var_;
+      perm_string index_var_;
+      Statement*statement_;
+};
+
 class PForever : public Statement {
     public:
       explicit PForever(Statement*s);

elab_scope.cc

@@ -1890,6 +1890,18 @@ void PEventStatement::elaborate_scope(Design*des, NetScope*scope) const
 	    statement_ -> elaborate_scope(des, scope);
 }
 
+/*
+ * The standard says that we create an implicit scope for foreach
+ * loops, but that is just to hold the index variables, and we'll
+ * handle them by creating unique names. So just jump into the
+ * contained statement for scope elaboration.
+ */
+void PForeach::elaborate_scope(Design*des, NetScope*scope) const
+{
+      if (statement_)
+	    statement_ -> elaborate_scope(des, scope);
+}
+
 /*
  * Statements that contain a further statement but do not
  * intrinsically add a scope need to elaborate_scope the contained

elab_sig.cc

@@ -806,6 +806,12 @@ void PEventStatement::elaborate_sig(Design*des, NetScope*scope) const
 	    statement_->elaborate_sig(des, scope);
 }
 
+void PForeach::elaborate_sig(Design*des, NetScope*scope) const
+{
+      if (statement_)
+	    statement_->elaborate_sig(des, scope);
+}
+
 void PForever::elaborate_sig(Design*des, NetScope*scope) const
 {
       if (statement_)

elaborate.cc

@@ -4575,6 +4575,65 @@ NetForce* PForce::elaborate(Design*des, NetScope*scope) const
       return dev;
 }
 
+/*
+ * The foreach statement can be written as a for statement like so:
+ *
+ *     for (<idx> = $low(<array>) ; <idx> <= $high(<array>) ; <idx> += 1)
+ *          <statement_>
+ *
+ * The <idx> variable is already known to be in the containing named
+ * block scope, which was created by the parser.
+ */
+NetProc* PForeach::elaborate(Design*des, NetScope*scope) const
+{
+	// Get the signal for the index variable.
+      pform_name_t index_name;
+      index_name.push_back(name_component_t(index_var_));
+      NetNet*idx_sig = des->find_signal(scope, index_name);
+      ivl_assert(*this, idx_sig);
+
+      NetESignal*idx_exp = new NetESignal(idx_sig);
+      idx_exp->set_line(*this);
+
+	// Get the signal for the array variable
+      pform_name_t array_name;
+      array_name.push_back(name_component_t(array_var_));
+      NetNet*array_sig = des->find_signal(scope, array_name);
+      ivl_assert(*this, array_sig);
+
+      NetESignal*array_exp = new NetESignal(array_sig);
+      array_exp->set_line(*this);
+
+	// Make an initialization expression for the index.
+      NetESFunc*init_expr = new NetESFunc("$low", IVL_VT_BOOL, 32, 1);
+      init_expr->set_line(*this);
+      init_expr->parm(0, array_exp);
+
+	// Make a condition expression: idx <= $high(array)
+      NetESFunc*high_exp = new NetESFunc("$high", IVL_VT_BOOL, 32, 1);
+      high_exp->set_line(*this);
+      high_exp->parm(0, array_exp);
+
+      NetEBComp*cond_expr = new NetEBComp('L', idx_exp, high_exp);
+      cond_expr->set_line(*this);
+
+	/* Elaborate the statement that is contained in the foreach
+	   loop. */
+      NetProc*sub = statement_->elaborate(des, scope);
+
+	/* Make a step statement: idx += 1 */
+      NetAssign_*idx_lv = new NetAssign_(idx_sig);
+      NetEConst*step_val = make_const_val(1);
+      NetAssign*step = new NetAssign(idx_lv, '+', step_val);
+      step->set_line(*this);
+
+      NetForLoop*stmt = new NetForLoop(idx_sig, init_expr, cond_expr, sub, step);
+      stmt->set_line(*this);
+      stmt->wrap_up();
+
+      return stmt;
+}
+
 /*
  * elaborate the for loop as the equivalent while loop. This eases the
  * task for the target code generator. The structure is:

parse.y

@@ -1376,12 +1376,29 @@ loop_statement /* IEEE1800-2005: A.6.8 */
 	$$ = tmp;
       }
 
-  | K_foreach '(' IDENTIFIER '[' loop_variables ']' ')' statement_or_null
-      { yyerror(@1, "sorry: foreach loops not supported");
-	delete[]$3;
-	delete $5;
-	delete $8;
-	$$ = 0;
+      // When matching a foreach loop, implicitly create a named block
+      // to hold the definitions for the index variables.
+  | K_foreach '(' IDENTIFIER '[' loop_variables ']' ')'
+      { static unsigned foreach_counter = 0;
+	char for_block_name[64];
+	snprintf(for_block_name, sizeof for_block_name, "$ivl_foreach%u", foreach_counter);
+	foreach_counter += 1;
+
+	PBlock*tmp = pform_push_block_scope(for_block_name, PBlock::BL_SEQ);
+	FILE_NAME(tmp, @1);
+	current_block_stack.push(tmp);
+
+	pform_make_foreach_declarations(@1, $5);
+      }
+    statement_or_null
+      { PForeach*tmp_for = pform_make_foreach(@1, $3, $5, $9);
+
+	pform_pop_scope();
+	vector<Statement*>tmp_for_list(1);
+	tmp_for_list[0] = tmp_for;
+	PBlock*tmp_blk = current_block_stack.top();
+	tmp_blk->set_statement(tmp_for_list);
+	$$ = tmp_blk;
       }
 
   /* Error forms for loop statements. */

pform.cc

@@ -704,6 +704,42 @@ PCallTask* pform_make_call_task(const struct vlltype&loc,
       return tmp;
 }
 
+void pform_make_foreach_declarations(const struct vlltype&loc,
+				     std::list<perm_string>*loop_vars)
+{
+      static const struct str_pair_t str = { IVL_DR_STRONG, IVL_DR_STRONG };
+
+      list<decl_assignment_t*>assign_list;
+      for (list<perm_string>::const_iterator cur = loop_vars->begin()
+		 ; cur != loop_vars->end() ; ++ cur) {
+	    decl_assignment_t*tmp_assign = new decl_assignment_t;
+	    tmp_assign->name = lex_strings.make(*cur);
+	    assign_list.push_back(tmp_assign);
+      }
+
+      pform_makewire(loc, 0, str, &assign_list, NetNet::REG, &size_type);
+}
+
+PForeach* pform_make_foreach(const struct vlltype&loc,
+			     char*name,
+			     list<perm_string>*loop_vars,
+			     Statement*stmt)
+{
+      perm_string use_name = lex_strings.make(name);
+      delete[]name;
+
+      perm_string use_index = loop_vars->front();
+      loop_vars->pop_front();
+
+      ivl_assert(loc, loop_vars->empty());
+      delete loop_vars;
+
+      PForeach*fe = new PForeach(use_name, use_index, stmt);
+      FILE_NAME(fe, loc);
+
+      return fe;
+}
+
 static void pform_put_behavior_in_scope(PProcess*pp)
 {
       lexical_scope->behaviors.push_back(pp);

pform.h

@@ -285,6 +285,12 @@ extern PCallTask* pform_make_call_task(const struct vlltype&loc,
 				       const pform_name_t&name,
 				       const std::list<PExpr*>&parms);
 
+extern void pform_make_foreach_declarations(const struct vlltype&loc,
+					    std::list<perm_string>*loop_vars);
+extern PForeach* pform_make_foreach(const struct vlltype&loc,
+				    char*ident,
+				    std::list<perm_string>*loop_vars,
+				    Statement*stmt);
 
 /*
  * The makewire functions announce to the pform code new wires. These
@@ -349,7 +355,7 @@ extern void pform_set_data_type(const struct vlltype&li, data_type_t*, list<perm
 
 extern void pform_set_struct_type(struct_type_t*struct_type, std::list<perm_string>*names, NetNet::Type net_type, std::list<named_pexpr_t>*attr);
 
-extern void pform_set_string_type(string_type_t*string_type, std::list<perm_string>*names, NetNet::Type net_type, std::list<named_pexpr_t>*attr);
+extern void pform_set_string_type(const string_type_t*string_type, std::list<perm_string>*names, NetNet::Type net_type, std::list<named_pexpr_t>*attr);
 
 extern void pform_set_class_type(class_type_t*class_type, std::list<perm_string>*names, NetNet::Type net_type, std::list<named_pexpr_t>*addr);
 

pform_dump.cc

@@ -967,6 +967,15 @@ void PForce::dump(ostream&out, unsigned ind) const
 	  << "; /* " << get_fileline() << " */" << endl;
 }
 
+void PForeach::dump(ostream&fd, unsigned ind) const
+{
+      fd << setw(ind) << "" << "foreach "
+	 << "variable=" << array_var_
+	 << ", index=" << index_var_
+	 << " /* " << get_fileline() << " */" << endl;
+      statement_->dump(fd, ind+3);
+}
+
 void PForever::dump(ostream&out, unsigned ind) const
 {
       out << setw(ind) << "" << "forever /* " << get_fileline() << " */" << endl;

pform_string_type.cc

@@ -21,13 +21,13 @@
 # include  "parse_misc.h"
 # include  "ivl_assert.h"
 
-static void pform_set_string_type(string_type_t*, perm_string name, NetNet::Type net_type, list<named_pexpr_t>*attr)
+static void pform_set_string_type(const string_type_t*, perm_string name, NetNet::Type net_type, list<named_pexpr_t>*attr)
 {
       PWire*net = pform_get_make_wire_in_scope(name, net_type, NetNet::NOT_A_PORT, IVL_VT_STRING);
       pform_bind_attributes(net->attributes, attr, true);
 }
 
-void pform_set_string_type(string_type_t*string_type, list<perm_string>*names, NetNet::Type net_type, list<named_pexpr_t>*attr)
+void pform_set_string_type(const string_type_t*string_type, list<perm_string>*names, NetNet::Type net_type, list<named_pexpr_t>*attr)
 {
       for (list<perm_string>::iterator cur = names->begin()
 		 ; cur != names->end() ; ++ cur) {

pform_types.cc

@@ -42,3 +42,5 @@ ivl_variable_type_t vector_type_t::figure_packed_base_type(void) const
 {
       return base_type;
 }
+
+atom2_type_t size_type (32, true);

pform_types.h

@@ -182,6 +182,8 @@ struct atom2_type_t : public data_type_t {
       ivl_type_s* elaborate_type_raw(Design*des, NetScope*scope) const;
 };
 
+extern atom2_type_t size_type;
+
 /*
  * The vector_type_t class represents types in the old Verilog
  * way. Some typical examples: