Objects of lexical scope use PScope base class.

All the pform objects that represent lexical scope now are derived
from the PScope class, and are kept in a lexical_scope table so that
the scope can be managed.

Module.cc

@@ -29,7 +29,7 @@
 
 /* n is a permallocated string. */
 Module::Module(perm_string n)
-: PScope(n)
+: PScope(n, 0)
 {
       library_flag = false;
       default_nettype = NetNet::NONE;

PFunction.cc

@@ -21,8 +21,8 @@
 
 #include "PTask.h"
 
-PFunction::PFunction(perm_string name)
+PFunction::PFunction(perm_string name, PScope*parent)
-: PScope(name), ports_(0), statement_(0)
+: PScope(name, parent), ports_(0), statement_(0)
 {
       return_type_.type = PTF_NONE;
 }

PScope.cc

@@ -19,8 +19,8 @@
 
 # include  "PScope.h"
 
-PScope::PScope(perm_string n)
+PScope::PScope(perm_string n, PScope*p)
-: name_(n)
+    : name_(n), parent_(p)
 {
 }
 

PScope.h

@@ -20,14 +20,15 @@
  */
 
 # include  "StringHeap.h"
+# include  "pform_types.h"
 # include  <map>
 
 class PEvent;
 
 /*
  * The PScope class is a base representation of an object that
- * represents some sort of compile-time scope. For example, a module,
+ * represents lexical scope. For example, a module, a function/task, a
- * a function/task, a named block is derived from a PScope.
+ * named block is derived from a PScope.
  *
  * NOTE: This is note the same concept as the "scope" of an elaborated
  * hierarchy. That is represented by NetScope objects after elaboration.
@@ -35,16 +36,26 @@ class PEvent;
 class PScope {
 
     public:
-      PScope(perm_string name);
+	// When created, a scope has a name and a parent. The name is
-      ~PScope();
+	// the name of the definition. For example, if this is a
+	// module declaration, the name is the name after the "module"
+	// keyword, and if this is a task scope, the name is the task
+	// name. The parent is the lexical parent of this scope. Since
+	// modules do not nest in Verilog, the parent must be nil for
+	// modules. Scopes for tasks and functions point to their
+	// containing module.
+      PScope(perm_string name, PScope*parent);
+      virtual ~PScope();
 
       perm_string pscope_name() const { return name_; }
+      PScope* pscope_parent() { return parent_; }
 
 	// Named events in the scope.
       map<perm_string,PEvent*>events;
 
     private:
       perm_string name_;
+      PScope*parent_;
 };
 
 #endif

PTask.cc

@@ -21,8 +21,8 @@
 
 # include  "PTask.h"
 
-PTask::PTask(perm_string name)
+PTask::PTask(perm_string name, PScope*parent)
-: PScope(name), ports_(0), statement_(0)
+: PScope(name, parent), ports_(0), statement_(0)
 {
 }
 

PTask.h

@@ -51,7 +51,7 @@ struct PTaskFuncArg {
 class PTask  : public PScope, public LineInfo {
 
     public:
-      explicit PTask(perm_string name);
+      explicit PTask(perm_string name, PScope*parent);
       ~PTask();
 
       void set_ports(svector<PWire *>*p);
@@ -90,7 +90,7 @@ class PTask  : public PScope, public LineInfo {
 class PFunction : public PScope, public LineInfo {
 
     public:
-      explicit PFunction(perm_string name);
+      explicit PFunction(perm_string name, PScope*parent);
       ~PFunction();
 
       void set_ports(svector<PWire *>*p);

Statement.cc

@@ -86,18 +86,13 @@ PAssignNB::~PAssignNB()
 {
 }
 
-PBlock::PBlock(perm_string n, BL_TYPE t, const svector<Statement*>&st)
+PBlock::PBlock(perm_string n, PScope*parent, BL_TYPE t)
-: name_(n), bl_type_(t), list_(st)
+: PScope(n, parent), bl_type_(t)
-{
-}
-
-PBlock::PBlock(BL_TYPE t, const svector<Statement*>&st)
-: bl_type_(t), list_(st)
 {
 }
 
 PBlock::PBlock(BL_TYPE t)
-: bl_type_(t)
+: PScope(perm_string(),0), bl_type_(t)
 {
 }
 
@@ -107,6 +102,11 @@ PBlock::~PBlock()
 	    delete list_[idx];
 }
 
+void PBlock::set_statement(const svector<Statement*>&st)
+{
+      list_ = st;
+}
+
 PCallTask::PCallTask(const pform_name_t&n, const svector<PExpr*>&p)
 : path_(n), parms_(p)
 {

Statement.h

@@ -27,6 +27,7 @@
 # include  "StringHeap.h"
 # include  "PDelays.h"
 # include  "PExpr.h"
+# include  "PScope.h"
 # include  "HName.h"
 # include  "LineInfo.h"
 class PExpr;
@@ -147,25 +148,26 @@ class PAssignNB  : public PAssign_ {
  * statements before constructing this object, so it knows a priori
  * what is contained.
  */
-class PBlock  : public Statement {
+class PBlock  : public PScope, public Statement {
 
     public:
       enum BL_TYPE { BL_SEQ, BL_PAR };
 
-      explicit PBlock(perm_string n, BL_TYPE t, const svector<Statement*>&st);
+	// If the block has a name, it is a scope and also has a parent.
-      explicit PBlock(BL_TYPE t, const svector<Statement*>&st);
+      explicit PBlock(perm_string n, PScope*parent, BL_TYPE t);
+	// If it doesn't have a name, it's not a scope
       explicit PBlock(BL_TYPE t);
       ~PBlock();
 
       BL_TYPE bl_type() const { return bl_type_; }
 
+      void set_statement(const svector<Statement*>&st);
 
       virtual void dump(ostream&out, unsigned ind) const;
       virtual NetProc* elaborate(Design*des, NetScope*scope) const;
       virtual void elaborate_scope(Design*des, NetScope*scope) const;
 
     private:
-      perm_string name_;
       const BL_TYPE bl_type_;
       svector<Statement*>list_;
 };

elab_scope.cc

@@ -794,8 +794,8 @@ void PBlock::elaborate_scope(Design*des, NetScope*scope) const
 {
       NetScope*my_scope = scope;
 
-      if (name_ != 0) {
+      if (pscope_name() != 0) {
-	    hname_t use_name(name_);
+	    hname_t use_name(pscope_name());
 	    if (scope->child(use_name)) {
 		  cerr << get_fileline() << ": error: block/scope name "
 		       << use_name << " already used in this context."

elaborate.cc

@@ -1846,12 +1846,12 @@ NetProc* PBlock::elaborate(Design*des, NetScope*scope) const
 	    : NetBlock::SEQU;
 
       NetScope*nscope = 0;
-      if (name_.str() != 0) {
+      if (pscope_name() != 0) {
-	    nscope = scope->child(hname_t(name_));
+	    nscope = scope->child(hname_t(pscope_name()));
 	    if (nscope == 0) {
 		  cerr << get_fileline() << ": internal error: "
 			"unable to find block scope " << scope_path(scope)
-		       << "<" << name_ << ">" << endl;
+		       << "<" << pscope_name() << ">" << endl;
 		  des->errors += 1;
 		  return 0;
 	    }
@@ -1869,7 +1869,7 @@ NetProc* PBlock::elaborate(Design*des, NetScope*scope) const
 	// statement. There is no need to keep the block node. Also,
 	// don't elide named blocks, because they might be referenced
 	// elsewhere.
-      if ((list_.count() == 1) && (name_.str() == 0)) {
+      if ((list_.count() == 1) && (pscope_name() == 0)) {
 	    assert(list_[0]);
 	    NetProc*tmp = list_[0]->elaborate(des, nscope);
 	    return tmp;

parse.y

@@ -45,6 +45,12 @@ static struct {
       svector<PExpr*>* range;
 } port_declaration_context;
 
+/* The task and function rules need to briefly hold the pointer to the
+   task/function that is currently in progress. */
+static PTask* current_task = 0;
+static PFunction* current_function = 0;
+static PBlock* current_block = 0;
+
 /* Later version of bison (including 1.35) will not compile in stack
    extension if the output is compiled with C++ and either the YYSTYPE
    or YYLTYPE are provided by the source code. However, I can get the
@@ -1843,33 +1849,31 @@ module_item
      extension. */
 
   | K_task IDENTIFIER ';'
-      { pform_push_scope($2); }
+      { current_task = pform_push_task_scope($2);
+	FILE_NAME(current_task, @1);
+      }
     task_item_list_opt
     statement_or_null
     K_endtask
-      { perm_string task_name = lex_strings.make($2);
+      { current_task->set_ports($5);
-	PTask*tmp = new PTask(task_name);
+	current_task->set_statement($6);
-	FILE_NAME(tmp, @1);
-	tmp->set_ports($5);
-	tmp->set_statement($6);
-	pform_set_task(task_name, tmp);
 	pform_pop_scope();
+	current_task = 0;
 	delete $2;
       }
 
   | K_task IDENTIFIER
-      { pform_push_scope($2); }
+      { current_task = pform_push_task_scope($2);
+	FILE_NAME(current_task, @1);
+      }
     '(' task_port_decl_list ')' ';'
     task_item_list_opt
     statement_or_null
     K_endtask
-      { perm_string task_name = lex_strings.make($2);
+      { current_task->set_ports($5);
-	PTask*tmp = new PTask(task_name);
+	current_task->set_statement($9);
-	FILE_NAME(tmp, @1);
-	tmp->set_ports($5);
-	tmp->set_statement($9);
-	pform_set_task(task_name, tmp);
 	pform_pop_scope();
+	current_task = 0;
 	delete $2;
       }
 
@@ -1879,17 +1883,14 @@ module_item
      instead of the module. */
 
   | K_function function_range_or_type_opt IDENTIFIER ';'
-                { pform_push_scope($3); }
+      { current_function = pform_push_function_scope($3); }
     function_item_list statement
     K_endfunction
-		{ perm_string name = lex_strings.make($3);
+      { current_function->set_ports($6);
-		  PFunction *tmp = new PFunction(name);
+	current_function->set_statement($7);
-		  FILE_NAME(tmp, @1);
+	current_function->set_return($2);
-		  tmp->set_ports($6);
-		  tmp->set_statement($7);
-		  tmp->set_return($2);
-		  pform_set_function(name, tmp);
 	pform_pop_scope();
+	current_function = 0;
 	delete $3;
       }
 
@@ -2962,22 +2963,23 @@ statement
      the declarations. The scope is popped at the end of the block. */
 
   | K_begin statement_list K_end
-		{ PBlock*tmp = new PBlock(PBlock::BL_SEQ, *$2);
+      { PBlock*tmp = new PBlock(PBlock::BL_SEQ);
 	FILE_NAME(tmp, @1);
+	tmp->set_statement(*$2);
 	delete $2;
 	$$ = tmp;
       }
   | K_begin ':' IDENTIFIER
-		{ pform_push_scope($3); }
+      { current_block = pform_push_block_scope($3, PBlock::BL_SEQ);
+	FILE_NAME(current_block, @1);
+      }
     block_item_decls_opt
     statement_list K_end
       { pform_pop_scope();
-		  PBlock*tmp = new PBlock(lex_strings.make($3),
+	current_block->set_statement(*$6);
-					  PBlock::BL_SEQ, *$6);
-		  FILE_NAME(tmp, @1);
 	delete $3;
 	delete $6;
-		  $$ = tmp;
+	$$ = current_block;
       }
   | K_begin K_end
       { PBlock*tmp = new PBlock(PBlock::BL_SEQ);
@@ -2998,16 +3000,16 @@ statement
      code generator can do the right thing. */
 
   | K_fork ':' IDENTIFIER
-		{ pform_push_scope($3); }
+      { current_block = pform_push_block_scope($3, PBlock::BL_PAR);
+	FILE_NAME(current_block, @1);
+      }
     block_item_decls_opt
     statement_list K_join
       { pform_pop_scope();
-		  PBlock*tmp = new PBlock(lex_strings.make($3),
+	current_block->set_statement(*$6);
-					  PBlock::BL_PAR, *$6);
-		  FILE_NAME(tmp, @1);
 	delete $3;
 	delete $6;
-		  $$ = tmp;
+	$$ = current_block;
       }
   | K_fork K_join
       { PBlock*tmp = new PBlock(PBlock::BL_PAR);
@@ -3039,8 +3041,9 @@ statement
 		  $$ = tmp;
 		}
 	| K_fork statement_list K_join
-		{ PBlock*tmp = new PBlock(PBlock::BL_PAR, *$2);
+		{ PBlock*tmp = new PBlock(PBlock::BL_PAR);
 		  FILE_NAME(tmp, @1);
+		  tmp->set_statement(*$2);
 		  delete $2;
 		  $$ = tmp;
 		}

pform.cc

@@ -38,6 +38,7 @@
 
 # include  "ivl_assert.h"
 
+
 map<perm_string,Module*> pform_modules;
 map<perm_string,PUdp*> pform_primitives;
 
@@ -103,6 +104,7 @@ static inline void FILE_NAME(LineInfo*tmp, const struct vlltype&where)
  */
 
 static pform_name_t scope_stack;
+static PScope* lexical_scope = 0;
 
 void pform_push_scope(char*name)
 {
@@ -112,6 +114,7 @@ void pform_push_scope(char*name)
 void pform_pop_scope()
 {
       scope_stack.pop_back();
+      lexical_scope = lexical_scope->pscope_parent();
 }
 
 static pform_name_t hier_name(const char*tail)
@@ -121,6 +124,41 @@ static pform_name_t hier_name(const char*tail)
       return name;
 }
 
+PTask* pform_push_task_scope(char*name)
+{
+      pform_push_scope(name);
+      perm_string task_name = lex_strings.make(name);
+      PTask*task = new PTask(task_name, pform_cur_module);
+
+	// Add the task to the current module
+      pform_cur_module->add_task(task->pscope_name(), task);
+	// Make this the current lexical scope
+      lexical_scope = task;
+      return task;
+}
+
+PFunction* pform_push_function_scope(char*name)
+{
+      pform_push_scope(name);
+      perm_string func_name = lex_strings.make(name);
+      PFunction*func = new PFunction(func_name, lexical_scope);
+
+	// Add the task to the current module
+      pform_cur_module->add_function(func->pscope_name(), func);
+	// Make this the current lexical scope
+      lexical_scope = func;
+      return func;
+}
+
+PBlock* pform_push_block_scope(char*name, PBlock::BL_TYPE bt)
+{
+      pform_push_scope(name);
+      perm_string block_name = lex_strings.make(name);
+      PBlock*block = new PBlock(block_name, lexical_scope, bt);
+
+      return block;
+}
+
 static PWire*get_wire_in_module(const pform_name_t&name)
 {
 	/* Note that if we are processing a generate, then the
@@ -1590,17 +1628,6 @@ svector<PWire*>*pform_make_task_ports(NetNet::PortType pt,
       return res;
 }
 
-void pform_set_task(perm_string name, PTask*task)
-{
-      pform_cur_module->add_task(name, task);
-}
-
-
-void pform_set_function(perm_string name, PFunction*func)
-{
-      pform_cur_module->add_function(name, func);
-}
-
 void pform_set_attrib(perm_string name, perm_string key, char*value)
 {
       pform_name_t path = hier_name(name);

pform.h

@@ -167,9 +167,12 @@ extern void pform_make_udp(perm_string name,
  * name string onto the scope hierarchy. The pop pulls it off and
  * deletes it. Thus, the string pushed must be allocated.
  */
-extern void pform_push_scope(char*name);
 extern void pform_pop_scope();
 
+extern PTask*pform_push_task_scope(char*name);
+extern PFunction*pform_push_function_scope(char*name);
+extern PBlock*pform_push_block_scope(char*name, PBlock::BL_TYPE tt);
+
 
 extern verinum* pform_verinum_with_size(verinum*s, verinum*val,
 					const char*file, unsigned loneno);
@@ -248,8 +251,6 @@ extern void pform_set_net_range(list<perm_string>*names,
 extern void pform_set_reg_idx(const char*name, PExpr*l, PExpr*r);
 extern void pform_set_reg_integer(list<perm_string>*names);
 extern void pform_set_reg_time(list<perm_string>*names);
-extern void pform_set_task(perm_string name, PTask*);
-extern void pform_set_function(perm_string name, PFunction*);
 
   /* pform_set_attrib and pform_set_type_attrib exist to support the
      $attribute syntax, which can only set string values to

pform_dump.cc

@@ -504,8 +504,8 @@ void PAssignNB::dump(ostream&out, unsigned ind) const
 void PBlock::dump(ostream&out, unsigned ind) const
 {
       out << setw(ind) << "" << "begin";
-      if (name_ != 0)
+      if (pscope_name() != 0)
-	    out << " : " << name_;
+	    out << " : " << pscope_name();
       out << endl;
 
       for (unsigned idx = 0 ;  idx < list_.count() ;  idx += 1) {