Fully support variable initialization in tasks/functions/named blocks.

(cherry picked from commit 635adfc01e)

PScope.h

@@ -1,7 +1,7 @@
 #ifndef IVL_PScope_H
 #define IVL_PScope_H
 /*
- * Copyright (c) 2008-2014 Stephen Williams (steve@icarus.com)
+ * Copyright (c) 2008-2016 Stephen Williams (steve@icarus.com)
  *
  *    This source code is free software; you can redistribute it
  *    and/or modify it in source code form under the terms of the GNU
@@ -36,6 +36,7 @@ class PProcess;
 class PClass;
 class PTask;
 class PWire;
+class Statement;
 
 class Design;
 class NetScope;
@@ -108,6 +109,9 @@ class LexicalScope {
         // creating implicit nets.
       map<perm_string,LineInfo*> genvars;
 
+	// Variable initializations in this scope
+      vector<Statement*> var_inits;
+
 	// Behaviors (processes) in this scope
       list<PProcess*> behaviors;
       list<AProcess*> analog_behaviors;
@@ -130,6 +134,10 @@ class LexicalScope {
 
       void dump_wires_(ostream&out, unsigned indent) const;
 
+      void dump_var_inits_(ostream&out, unsigned indent) const;
+
+      bool elaborate_var_inits_(Design*des, NetScope*scope) const;
+
     private:
       LexicalScope*parent_;
 };

elaborate.cc

@@ -2894,14 +2894,27 @@ NetProc* PBlock::elaborate(Design*des, NetScope*scope) const
 		  des->errors += 1;
 		  return 0;
 	    }
-
 	    assert(nscope);
-
-	    elaborate_behaviors_(des, nscope);
       }
 
       NetBlock*cur = new NetBlock(type, nscope);
 
+      if (nscope) {
+	      // Handle any variable initialization statements in this scope.
+	      // For automatic scopes these statements need to be executed
+	      // each time the block is entered, so add them to the main
+	      // block. For static scopes, put them in a separate process
+	      // that will be executed at the start of simulation.
+	    if (nscope->is_auto()) {
+		  for (unsigned idx = 0; idx < var_inits.size(); idx += 1) {
+			NetProc*tmp = var_inits[idx]->elaborate(des, nscope);
+			if (tmp) cur->append(tmp);
+		  }
+	    } else {
+		  elaborate_var_inits_(des, nscope);
+	    }
+      }
+
       if (nscope == 0)
 	    nscope = scope;
 
@@ -5023,7 +5036,6 @@ void PFunction::elaborate(Design*des, NetScope*scope) const
 	    des->errors += 1;
 	    return;
       }
-
       assert(def);
 
       ivl_assert(*this, statement_);
@@ -5036,6 +5048,31 @@ void PFunction::elaborate(Design*des, NetScope*scope) const
 	    return;
       }
 
+	// Handle any variable initialization statements in this scope.
+	// For automatic functions, these statements need to be executed
+	// each time the function is called, so insert them at the start
+	// of the elaborated definition. For static functions, put them
+	// in a separate process that will be executed before the start
+	// of simulation.
+      if (is_auto_) {
+	      // Get the NetBlock of the statement. If it is not a
+	      // NetBlock then create one to wrap the initialization
+	      // statements and the original statement.
+	    NetBlock*blk = dynamic_cast<NetBlock*> (st);
+	    if ((blk == 0) && (var_inits.size() > 0)) {
+		  blk = new NetBlock(NetBlock::SEQU, scope);
+		  blk->set_line(*this);
+		  blk->append(st);
+		  st = blk;
+	    }
+	    for (unsigned idx = var_inits.size(); idx > 0; idx -= 1) {
+		  NetProc*tmp = var_inits[idx-1]->elaborate(des, scope);
+		  if (tmp) blk->prepend(tmp);
+	    }
+      } else {
+	    elaborate_var_inits_(des, scope);
+      }
+
       def->set_proc(st);
 }
 
@@ -5198,11 +5235,6 @@ NetProc* PReturn::elaborate(Design*des, NetScope*scope) const
 
 void PTask::elaborate(Design*des, NetScope*task) const
 {
-	// Elaborate any processes that are part of this scope that
-	// aren't the definition itself. This can happen, for example,
-	// with variable initialization statements in this scope.
-      elaborate_behaviors_(des, task);
-
       NetTaskDef*def = task->task_def();
       assert(def);
 
@@ -5221,6 +5253,31 @@ void PTask::elaborate(Design*des, NetScope*task) const
 	    }
       }
 
+	// Handle any variable initialization statements in this scope.
+	// For automatic tasks , these statements need to be executed
+	// each time the task is called, so insert them at the start
+	// of the elaborated definition. For static tasks, put them
+	// in a separate process that will be executed before the start
+	// of simulation.
+      if (is_auto_) {
+	      // Get the NetBlock of the statement. If it is not a
+	      // NetBlock then create one to wrap the initialization
+	      // statements and the original statement.
+	    NetBlock*blk = dynamic_cast<NetBlock*> (st);
+	    if ((blk == 0) && (var_inits.size() > 0)) {
+		  blk = new NetBlock(NetBlock::SEQU, task);
+		  blk->set_line(*this);
+		  blk->append(st);
+		  st = blk;
+	    }
+	    for (unsigned idx = var_inits.size(); idx > 0; idx -= 1) {
+		  NetProc*tmp = var_inits[idx-1]->elaborate(des, task);
+		  if (tmp) blk->prepend(tmp);
+	    }
+      } else {
+	    elaborate_var_inits_(des, task);
+      }
+
       def->set_proc(st);
 }
 
@@ -5677,6 +5734,10 @@ bool Module::elaborate(Design*des, NetScope*scope) const
 	    (*gt)->elaborate(des, scope);
       }
 
+	// Elaborate the variable initialization statements, making a
+	// single initial process out of them.
+      result_flag &= elaborate_var_inits_(des, scope);
+
 	// Elaborate the behaviors, making processes out of them. This
 	// involves scanning the PProcess* list, creating a NetProcTop
 	// for each process.
@@ -5867,6 +5928,8 @@ bool PGenerate::elaborate_(Design*des, NetScope*scope) const
       for (gates_it_t cur = gates.begin() ; cur != gates.end() ; ++ cur )
 	    (*cur)->elaborate(des, scope);
 
+      elaborate_var_inits_(des, scope);
+
       typedef list<PProcess*>::const_iterator proc_it_t;
       for (proc_it_t cur = behaviors.begin(); cur != behaviors.end(); ++ cur )
 	    (*cur)->elaborate(des, scope);
@@ -5902,6 +5965,37 @@ bool PScope::elaborate_behaviors_(Design*des, NetScope*scope) const
       return result_flag;
 }
 
+bool LexicalScope::elaborate_var_inits_(Design*des, NetScope*scope) const
+{
+      if (var_inits.size() == 0)
+	    return true;
+
+      NetProc*proc = 0;
+      if (var_inits.size() == 1) {
+	    proc = var_inits[0]->elaborate(des, scope);
+      } else {
+	    NetBlock*blk = new NetBlock(NetBlock::SEQU, scope);
+	    bool flag = true;
+	    for (unsigned idx = 0; idx < var_inits.size(); idx += 1) {
+		  NetProc*tmp = var_inits[idx]->elaborate(des, scope);
+		  if (tmp)
+			blk->append(tmp);
+		  else
+			flag = false;
+	    }
+	    if (flag) proc = blk;
+      }
+      if (proc == 0)
+	    return false;
+
+      NetProcTop*top = new NetProcTop(scope, IVL_PR_INITIAL, proc);
+      des->add_process(top);
+
+      scope->set_var_init(proc);
+
+      return true;
+}
+
 class elaborate_package_t : public elaborator_work_item_t {
     public:
       elaborate_package_t(Design*d, NetScope*scope, PPackage*p)

net_func_eval.cc

@@ -88,6 +88,10 @@ NetExpr* NetFuncDef::evaluate_function(const LineInfo&loc, const std::vector<Net
 	// fills in the context_map with local variables held by the scope.
       scope()->evaluate_function_find_locals(loc, context_map);
 
+	// Execute any variable initialization statements.
+      if (const NetProc*init_proc = scope()->var_init())
+	    init_proc->evaluate_function(loc, context_map);
+
       if (debug_eval_tree && proc_==0) {
 	    cerr << loc.get_fileline() << ": NetFuncDef::evaluate_function: "
 		 << "Function " << scope_path(scope())
@@ -505,6 +509,10 @@ bool NetBlock::evaluate_function(const LineInfo&loc,
 	      // Now collect the new locals.
 	    subscope_->evaluate_function_find_locals(loc, local_context_map);
 	    use_local_context_map = true;
+
+	      // Execute any variable initialization statements.
+	    if (const NetProc*init_proc = subscope_->var_init())
+		  init_proc->evaluate_function(loc, local_context_map);
       }
 
 	// Now use the local context map if there is any local

net_proc.cc

@@ -56,6 +56,17 @@ void NetBlock::append(NetProc*cur)
       }
 }
 
+void NetBlock::prepend(NetProc*cur)
+{
+      if (last_ == 0) {
+	    last_ = cur;
+	    cur->next_ = cur;
+      } else {
+	    cur->next_ = last_->next_;
+	    last_->next_ = cur;
+      }
+}
+
 const NetProc* NetBlock::proc_first() const
 {
       if (last_ == 0)

net_scope.cc

@@ -139,6 +139,7 @@ NetScope::NetScope(NetScope*up, const hname_t&n, NetScope::TYPE t, bool nest,
 	    time_from_timescale_ = false;
       }
 
+      var_init_ = 0;
       switch (t) {
 	  case NetScope::TASK:
 	    task_ = 0;

netlist.h

@@ -1020,6 +1020,13 @@ class NetScope : public Definitions, public Attrib {
       TYPE type() const;
       void print_type(ostream&) const;
 
+	// This provides a link to the variable initialisation process
+	// for use when evaluating a constant function. Note this is
+	// only used for static functions - the variable initialization
+	// for automatic functions is included in the function definition.
+      void set_var_init(const NetProc*proc) { var_init_ = proc; }
+      const NetProc* var_init() const { return var_init_; }
+
       void set_task_def(NetTaskDef*);
       void set_func_def(NetFuncDef*);
       void set_class_def(netclass_t*);
@@ -1250,6 +1257,8 @@ class NetScope : public Definitions, public Attrib {
 
       vector<PortInfo> ports_;
 
+      const NetProc*var_init_;
+
       union {
 	    NetTaskDef*task_;
 	    NetFuncDef*func_;
@@ -2904,6 +2913,7 @@ class NetBlock  : public NetProc {
       NetScope* subscope() const { return subscope_; }
 
       void append(NetProc*);
+      void prepend(NetProc*);
 
       const NetProc*proc_first() const;
       const NetProc*proc_next(const NetProc*cur) const;

parse.y

@@ -4223,7 +4223,7 @@ port_declaration
 	port_declaration_context.port_net_type = use_type;
 	port_declaration_context.data_type = $4;
 
-	pform_make_reginit(@5, name, $7);
+	pform_make_var_init(@5, name, $7);
 
 	delete[]$5;
 	$$ = ptmp;
@@ -4622,7 +4622,7 @@ module_item
 		       IVL_VT_NO_TYPE, $1, SR_BOTH);
 	for (pp = $6->begin(); pp != $6->end(); ++ pp ) {
 	      if ((*pp).second) {
-		   pform_make_reginit(@2, (*pp).first, (*pp).second);
+		   pform_make_var_init(@2, (*pp).first, (*pp).second);
 	      }
 	}
 	delete $6;
@@ -5486,7 +5486,7 @@ register_variable
 	pform_makewire(@1, name, NetNet::REG,
 		       NetNet::NOT_A_PORT, IVL_VT_NO_TYPE, 0);
 	pform_set_reg_idx(name, $2);
-	pform_make_reginit(@1, name, $4);
+	pform_make_var_init(@1, name, $4);
 	$$ = $1;
       }
   ;

pform.cc

@@ -2248,22 +2248,29 @@ void pform_make_pgassign_list(list<PExpr*>*alist,
 }
 
 /*
- * this function makes the initial assignment to a register as given
+ * This function makes the initial assignment to a variable as given
- * in the source. It handles the case where a reg variable is assigned
+ * in the source. It handles the case where a variable is assigned
- * where it it declared:
+ * where it is declared, e.g.
  *
  *    reg foo = <expr>;
  *
- * This is equivalent to the combination of statements:
+ * In Verilog-2001 this is only supported at the module level, and is
+ * equivalent to the combination of statements:
  *
  *    reg foo;
  *    initial foo = <expr>;
  *
- * and that is how it is parsed. This syntax is not part of the
+ * In SystemVerilog, variable initializations are allowed in any scope.
- * IEEE1364-1995 standard, but is approved by OVI as enhancement
+ * For static variables, initializations are performed before the start
- * BTF-B14.
+ * of simulation. For automatic variables, initializations are performed
+ * each time the enclosing block is entered. Here we store the variable
+ * assignments in the current scope, and later elaboration creates an
+ * initialization block that will be executed at the appropriate time.
+ *
+ * This syntax is not part of the IEEE1364-1995 standard, but is
+ * approved by OVI as enhancement BTF-B14.
  */
-void pform_make_reginit(const struct vlltype&li,
+void pform_make_var_init(const struct vlltype&li,
 			 perm_string name, PExpr*expr)
 {
       if (! pform_at_module_level() && !gn_system_verilog()) {
@@ -2275,7 +2282,7 @@ void pform_make_reginit(const struct vlltype&li,
 
       PWire*cur = pform_get_wire_in_scope(name);
       if (cur == 0) {
-	    VLerror(li, "internal error: reginit to non-register?");
+	    VLerror(li, "internal error: var_init to non-register?");
 	    delete expr;
 	    return;
       }
@@ -2284,10 +2291,8 @@ void pform_make_reginit(const struct vlltype&li,
       FILE_NAME(lval, li);
       PAssign*ass = new PAssign(lval, expr, true);
       FILE_NAME(ass, li);
-      PProcess*top = new PProcess(IVL_PR_INITIAL, ass);
-      FILE_NAME(top, li);
 
-      pform_put_behavior_in_scope(top);
+      lexical_scope->var_inits.push_back(ass);
 }
 
 /*

pform.h

@@ -351,7 +351,7 @@ extern void pform_makewire(const struct vlltype&li,
 			   list<perm_string>*names,
 			   list<named_pexpr_t>*attr);
 
-extern void pform_make_reginit(const struct vlltype&li,
+extern void pform_make_var_init(const struct vlltype&li,
 				perm_string name, PExpr*expr);
 
   /* Look up the names of the wires, and set the port type,

pform_dump.cc

@@ -789,6 +789,8 @@ void PBlock::dump(ostream&out, unsigned ind) const
             dump_events_(out, ind+2);
 
 	    dump_wires_(out, ind+2);
+
+	    dump_var_inits_(out, ind+2);
       }
 
       for (unsigned idx = 0 ;  idx < list_.size() ;  idx += 1) {
@@ -1030,6 +1032,8 @@ void PFunction::dump(ostream&out, unsigned ind) const
 
       dump_wires_(out, ind+2);
 
+      dump_var_inits_(out, ind+2);
+
       if (statement_)
 	    statement_->dump(out, ind+2);
       else
@@ -1072,6 +1076,8 @@ void PTask::dump(ostream&out, unsigned ind) const
 
       dump_wires_(out, ind+2);
 
+      dump_var_inits_(out, ind+2);
+
       if (statement_)
 	    statement_->dump(out, ind+2);
       else
@@ -1269,6 +1275,8 @@ void PGenerate::dump(ostream&out, unsigned indent) const
 	    (*idx)->dump(out, indent+2);
       }
 
+      dump_var_inits_(out, indent+2);
+
       for (list<PProcess*>::const_iterator idx = behaviors.begin()
 		 ; idx != behaviors.end() ; ++ idx ) {
 	    (*idx)->dump(out, indent+2);
@@ -1408,6 +1416,14 @@ void LexicalScope::dump_wires_(ostream&out, unsigned indent) const
       }
 }
 
+void LexicalScope::dump_var_inits_(ostream&out, unsigned indent) const
+{
+	// Iterate through and display all the register initializations.
+      for (unsigned idx = 0; idx < var_inits.size(); idx += 1) {
+	    var_inits[idx]->dump(out, indent);
+      }
+}
+
 void PScopeExtra::dump_classes_(ostream&out, unsigned indent) const
 {
 	// Dump the task definitions.
@@ -1564,6 +1580,7 @@ void Module::dump(ostream&out) const
 	    (*gate)->dump(out);
       }
 
+      dump_var_inits_(out, 4);
 
       for (list<PProcess*>::const_iterator behav = behaviors.begin()
 		 ; behav != behaviors.end() ; ++ behav ) {