Remove redundant back-end selections.

Target selection is done by the DLL target code generator, so there
is no value having a layer of target selection ahead of it. Remove
all that redundant code and simplify the target config files to reflect
this.

Makefile.in

@@ -110,7 +110,7 @@ net_proc.o net_scope.o net_tran.o net_udp.o pad_to_width.o \
 parse.o parse_misc.o pform.o pform_analog.o pform_disciplines.o \
 pform_dump.o pform_types.o \
 set_width.o symbol_search.o sync.o sys_funcs.o \
-verinum.o verireal.o target.o targets.o \
+verinum.o verireal.o target.o \
 Attrib.o HName.o LineInfo.o Module.o PDelays.o PEvent.o \
 PExpr.o PGate.o PGenerate.o PScope.o PSpec.o \
 PTask.o PUdp.o PFunction.o PWire.o Statement.o AStatement.o StringHeap.o \

emit.cc

@@ -540,17 +540,3 @@ void NetEUnary::expr_scan(struct expr_scan_t*tgt) const
 {
       tgt->expr_unary(this);
 }
-
-int emit(const Design*des, const char*type)
-{
-      for (unsigned idx = 0 ;  target_table[idx] ;  idx += 1) {
-	    const struct target*tgt = target_table[idx];
-	    if (strcmp(tgt->name, type) == 0)
-		  return des->emit(tgt->meth);
-
-      }
-
-      cerr << "error: Code generator type " << type
-	   << " not found." << endl;
-      return -1;
-}

main.cc

@@ -59,6 +59,7 @@ const char NOTICE[] =
 # include  "target.h"
 # include  "compiler.h"
 # include  "discipline.h"
+# include  "t-dll.h"
 
 #if defined(__MINGW32__) && !defined(HAVE_GETOPT_H)
 extern "C" int getopt(int argc, char*argv[], const char*fmt);
@@ -79,8 +80,6 @@ const char VERSION[] = "$Name:  $";
 
 const char*basedir = ".";
 
-const char*target = "null";
-
 /*
  * These are the language support control flags. These support which
  * language features (the generation) to support. The generation_flag
@@ -293,7 +292,7 @@ static void find_module_mention(map<perm_string,bool>&check_map, PGenerate*s);
  *    -T:<min/typ/max>
  *        Select which expression to use.
  *
- *    -t:<target>
+ *    -t:<target>    (obsolete)
  *        Usually, "-t:dll"
  *
  *    basedir:<path>
@@ -483,7 +482,7 @@ static void read_iconfig_file(const char*ipath)
 		  library_suff.push_back(strdup(cp));
 
 	    } else if (strcmp(buf,"-t") == 0) {
-		  target = strdup(cp);
+		    // NO LONGER USED
 
 	    } else if (strcmp(buf,"-T") == 0) {
 		  if (strcmp(cp,"min") == 0) {
@@ -844,20 +843,21 @@ int main(int argc, char*argv[])
       }
 
       if (verbose_flag) {
-	    cout << "CODE GENERATION -t "<<target<< endl;
+	    cout << "CODE GENERATION" << endl;
       }
 
-      int emit_rc;
+      if (int emit_rc = des->emit(&dll_target_obj)) {
-      emit_rc = emit(des, target);
+	    if (emit_rc > 0) {
-      if (emit_rc > 0) {
+		  cerr << "error: Code generation had "
-	    cerr << "error: Code generation had "
+		       << emit_rc << " errors."
-		 << emit_rc << " errors."
+		       << endl;
-		 << endl;
+		  return 1;
-	    return 1;
+	    }
-      }
+	    if (emit_rc < 0) {
-      if (emit_rc < 0) {
+		  cerr << "error: Code generator failure: " << emit_rc << endl;
-	    cerr << "error: Code generator failure: " << emit_rc << endl;
+		  return -1;
-	    return -1;
+	    }
+	    assert(emit_rc);
       }
 
       if (verbose_flag) {

t-dll.cc

@@ -32,6 +32,8 @@
 # include  <stdlib.h>
 # include  "ivl_assert.h"
 
+struct dll_target dll_target_obj;
+
 #if defined(__WIN32__)
 
 inline ivl_dll_t ivl_dlopen(const char *name)
@@ -144,8 +146,6 @@ static perm_string make_scope_name(const hname_t&name)
       return lex_strings.make(buf);
 }
 
-static struct dll_target dll_target_obj;
-
 static void drive_from_link(const Link&lnk, ivl_drive_t&drv0, ivl_drive_t&drv1)
 {
       switch (lnk.drive0()) {
@@ -2578,5 +2578,3 @@ bool dll_target::signal_paths(const NetNet*net)
 
       return true;
 }
-
-extern const struct target tgt_dll = { "dll", &dll_target_obj };

t-dll.h

@@ -178,6 +178,8 @@ struct dll_target  : public target_t, public expr_scan_t {
       static ivl_expr_t expr_from_value_(const verinum&that);
 };
 
+extern struct dll_target dll_target_obj;
+
 /*
  * These are various private declarations used by the t-dll target.
  */

target.h

@@ -151,11 +151,6 @@ struct expr_scan_t {
 };
 
 
-/* The emit functions take a design and emit it to the output stream
-   using the specified target. If the target is given by name, it is
-   located in the target_table and used. */
-extern int emit(const Design*des, const char*type);
-
 /* This function takes a fully qualified Verilog name (which may have,
    for example, dots in it) and produces a mangled version that can be
    used by most any language. */
@@ -165,8 +160,4 @@ extern string mangle(const string&str);
    used inside a string constant for a C++ compiler. */
 extern string stresc(const string&str);
 
-/* This is the table of supported output targets. It is a null
-   terminated array of pointers to targets. */
-extern const struct target *target_table[];
-
 #endif

targets.cc

@@ -1,29 +0,0 @@
-/*
- * Copyright (c) 1998 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
- *    General Public License as published by the Free Software
- *    Foundation; either version 2 of the License, or (at your option)
- *    any later version.
- *
- *    This program is distributed in the hope that it will be useful,
- *    but WITHOUT ANY WARRANTY; without even the implied warranty of
- *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *    GNU General Public License for more details.
- *
- *    You should have received a copy of the GNU General Public License
- *    along with this program; if not, write to the Free Software
- *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
- */
-
-# include "config.h"
-
-# include "target.h"
-
-extern const struct target tgt_dll;
-
-const struct target *target_table[] = {
-      &tgt_dll,
-      0
-};

tgt-null/null-s.conf

@@ -1,5 +1,4 @@
 functor:synth2
 functor:synth
 functor:syn-rules
--t:dll
 flag:DLL=null.tgt

tgt-null/null.conf

@@ -1,2 +1 @@
--t:dll
 flag:DLL=null.tgt

tgt-stub/stub-s.conf

@@ -3,5 +3,4 @@ functor:synth
 functor:syn-rules
 functor:cprop
 functor:nodangle
--t:dll
 flag:DLL=stub.tgt

tgt-stub/stub.conf

@@ -1,4 +1,3 @@
 functor:cprop
 functor:nodangle
--t:dll
 flag:DLL=stub.tgt

tgt-vhdl/vhdl.conf

@@ -1,4 +1,3 @@
 functor:cprop
 functor:nodangle
--t:dll
 flag:DLL=vhdl.tgt

tgt-vvp/vvp-s.conf.in

@@ -3,5 +3,4 @@ functor:synth
 functor:syn-rules
 functor:cprop
 functor:nodangle
--t:dll
 flag:DLL=vvp.tgt

tgt-vvp/vvp.conf.in

@@ -1,4 +1,3 @@
 functor:cprop
 functor:nodangle
--t:dll
 flag:DLL=vvp.tgt