1 files changed, 42 insertions, 0 deletions
diff --git a/src/vhdl/sem_decls.ads b/src/vhdl/sem_decls.ads
index 7a8e240..49ba43a 100644
--- a/src/vhdl/sem_decls.ads
+++ b/src/vhdl/sem_decls.ads
@@ -18,6 +18,7 @@
 with Iirs; use Iirs;
 
 package Sem_Decls is
+   --  Analyze an interface chain.
    procedure Sem_Interface_Chain (Interface_Chain: Iir;
                                   Interface_Kind : Interface_Kind_Type);
 
@@ -49,4 +50,45 @@ package Sem_Decls is
    --  is an overload list, it is destroyed.
    function Sem_Signature (Name : Iir; Sig : Iir_Signature) return Iir;
 
+   --  The attribute signals ('stable, 'quiet and 'transaction) are
+   --  implicitely declared.
+   --  Note: guard signals are also implicitly declared but with a guard
+   --   expression, which is at a known location.
+   --  Since these signals need resources and are not easily located (can be
+   --  nearly in every expression), it is useful to add a node into a
+   --  declaration list to declare them.
+   --  However, only a few declaration_list can declare signals.  These
+   --  declarations lists must register and unregister themselves with
+   --  push_declarative_region_with_signals and
+   --  pop_declarative_region_with_signals.
+   type Implicit_Signal_Declaration_Type is private;
+
+   procedure Push_Signals_Declarative_Part
+     (Cell: out Implicit_Signal_Declaration_Type; Decls_Parent : Iir);
+
+   procedure Pop_Signals_Declarative_Part
+     (Cell: in Implicit_Signal_Declaration_Type);
+
+   --  Declare an implicit signal.
+   procedure Add_Declaration_For_Implicit_Signal (Sig : Iir);
+
+private
+   type Implicit_Signal_Declaration_Type is record
+      --  Declaration or statement than will contain implicit declarations.
+      Decls_Parent : Iir;
+
+      --  If True, declarations of DECLS_PARENT have already been analyzed.
+      --  So implicit declarations are appended to the parent, and the last
+      --  declaration is LAST_IMPLICIT_DECL.
+      --  If False, declarations are being analyzed.  Implicit declarations
+      --  are saved in FIRST_IMPLICIT_DECL / LAST_IMPLICIT_DECL and will be
+      --  inserted before the current declaration.
+      Decls_Analyzed : Boolean;
+
+      --  If DECLS_ANALYZED is False, this is the chain of implicit
+      --  declarations.  If True, LAST_IMPLICIT_DECL contains the last
+      --  declaration.
+      First_Implicit_Decl : Iir;
+      Last_Implicit_Decl : Iir;
+   end record;
 end Sem_Decls;