From 79e193e0c94cd33fceecd755fcb41e9aae85ee63 Mon Sep 17 00:00:00 2001
From: Tim Edwards <tim@opencircuitdesign.com>
Date: Mon, 12 Sep 2022 11:26:21 -0400
Subject: [PATCH] Modified behavior for the "-noflatten" option on LVS:  Added
 a command option "flatten prohibit" (or "flatten deny") to prevent a subcell
 from being flattened at any time during the compare process.  Previously, the
 "-noflatten" option for the "lvs" script had been used to prevent flattening
 during initial pre-match, but if the circuit passed the prematch phase and
 subcells were mismatched, they would be flattened regardless of whether or
 not they were listed by the "-noflatten" option.  This also codifies a way to
 prevent subcells from being flattened in the setup file rather than in the
 "lvs" command line.  Also: Found and fixed a bug that prevents the use of
 "-noflatten=" with a cell name or list of cell names instead of a filename.

---
 VERSION             |  2 +-
 base/flatten.c      | 24 +++++++++++++++++-------
 tcltk/netgen.tcl.in |  4 +++-
 tcltk/tclnetgen.c   |  6 ++++++
 4 files changed, 27 insertions(+), 9 deletions(-)

diff --git a/VERSION b/VERSION
index ec27d32..12f037c 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-1.5.227
+1.5.228
diff --git a/base/flatten.c b/base/flatten.c
index 262570f..7c3b6a4 100644
--- a/base/flatten.c
+++ b/base/flatten.c
@@ -69,6 +69,10 @@ void flattenCell(char *name, int file)
     Printf("No cell %s found.\n", name);
     return;
   }
+
+  /* Placeholder cells must not be flattened */
+  if (ThisCell->flags & CELL_PLACEHOLDER) return;
+
   FreeNodeNames(ThisCell);
 
   ParentParams = ThisCell->cell;
@@ -288,6 +292,9 @@ int flattenInstancesOf(char *name, int fnum, char *instance)
       return 0;
     }
   }
+  /* Placeholder cells must not be flattened */
+  if (ThisCell->flags & CELL_PLACEHOLDER) return 0;
+
   FreeNodeNames(ThisCell);
 
   ParentParams = ThisCell->cell;
@@ -1620,19 +1627,22 @@ PrematchLists(char *name1, int file1, char *name2, int file2)
 		}
 	    }
 	    if (match) {
-		if (ecomp->cell1 && (ecomp->num1 > 0)) {
+		if (ecomp->cell1 && (ecomp->num1 > 0) &&
+				(!(ecomp->cell1->flags & CELL_PLACEHOLDER))) {
 		    Fprintf(stdout, "Flattening instances of %s in cell %s (%d)"
 				" makes a better match\n", ecomp->cell1->name,
 				name1, file1);
 		    flattenInstancesOf(name1, file1, ecomp->cell1->name); 
+		    modified++;
 		}
-		if (ecomp->cell2 && (ecomp->num2 > 0)) {
+		if (ecomp->cell2 && (ecomp->num2 > 0) &&
+				(!(ecomp->cell2->flags & CELL_PLACEHOLDER))) {
 		    Fprintf(stdout, "Flattening instances of %s in cell %s (%d)"
 				" makes a better match\n", ecomp->cell2->name,
 				name2, file2);
 		    flattenInstancesOf(name2, file2, ecomp->cell2->name); 
+		    modified++;
 		}
-		modified++;
 	    }
 
 	    /* Reset or apply the count adjustments */
@@ -1716,13 +1726,13 @@ PrematchLists(char *name1, int file1, char *name2, int file2)
 		if ((ecomp->num1 == 0) || (ecomp->cell1->class !=
 				CLASS_MODULE)) {
 
-		    if (ecomp->cell2) {
+		    if (ecomp->cell2 && !(ecomp->cell2->flags & CELL_PLACEHOLDER)) {
 		    	Fprintf(stdout, "Flattening instances of %s in cell %s (%d)"
 				" makes a better match\n", ecomp->cell2->name,
 				name2, file2);
 		    	flattenInstancesOf(name2, file2, ecomp->cell2->name); 
+		    	modified++;
 		    }
-		    modified++;
 		}
 	    }
 
@@ -1782,13 +1792,13 @@ PrematchLists(char *name1, int file1, char *name2, int file2)
 		if ((ecomp->num2 == 0) || (ecomp->cell2->class !=
 				CLASS_MODULE)) {
 
-		    if (ecomp->cell1) {
+		    if (ecomp->cell1 && !(ecomp->cell1->flags & CELL_PLACEHOLDER)) {
 		    	Fprintf(stdout, "Flattening instances of %s in cell %s (%d)"
 				" makes a better match\n", ecomp->cell1->name,
 				name1, file1);
 		    	flattenInstancesOf(name1, file1, ecomp->cell1->name); 
+		        modified++;
 		    }
-		    modified++;
 		}
 	    }
 
diff --git a/tcltk/netgen.tcl.in b/tcltk/netgen.tcl.in
index f63364f..f9c1ae8 100644
--- a/tcltk/netgen.tcl.in
+++ b/tcltk/netgen.tcl.in
@@ -393,7 +393,7 @@ proc netgen::lvs { name1 name2 {setupfile setup.tcl} {logfile comp.out} args} {
 	 # If argument is a filename then read the list of cells from it;
 	 # otherwise, argument is the list of files itself in quotes or
 	 # braces.
-	 if {![catch {file exists $value}]} {
+	 if {[file exists $value]} {
 	    if {![catch {open $value r} fnf]} {
 	       while {[gets $fnf line] >= 0} {
 		  if {[lindex $line 0] != "#"} {
@@ -569,6 +569,8 @@ proc netgen::lvs { name1 name2 {setupfile setup.tcl} {logfile comp.out} args} {
 	           netgen::log put "  Continuing with black-boxed subcircuits $endval\n"
 		   lappend matcherr [lindex $endval 0]"($fnum1)"
 		   lappend matcherr [lindex $endval 1]"($fnum2)"
+		   netgen::flatten prohibit "[lindex $endval 0] $fnum1"
+		   netgen::flatten prohibit "[lindex $endval 1] $fnum2"
 	           # Match pins
                    netgen::log echo off
 	           if {$dolist == 1} {
diff --git a/tcltk/tclnetgen.c b/tcltk/tclnetgen.c
index f6c573c..7a597ed 100644
--- a/tcltk/tclnetgen.c
+++ b/tcltk/tclnetgen.c
@@ -1056,6 +1056,12 @@ _netgen_flatten(ClientData clientData,
             FlattenInstancesOf(repstr, filenum);
 	 }
       }
+      else if (!strcmp(argv, "prohibit") || !strcmp(argv, "deny")) {
+	 tp = GetTopCell(filenum);
+	 Printf("Will not flatten instances of %s in file %s\n", repstr, tp->name);
+	 /* Mark cell as placeholder so it will not be flattened */
+	 tp->flags |= CELL_PLACEHOLDER;
+      }
       else {
 	 Tcl_WrongNumArgs(interp, 1, objv, "class valid_cellname");
 	 return TCL_ERROR;