From 63c4b7642cd4566a39906b2d73c47b4ebe9f7c1c Mon Sep 17 00:00:00 2001
From: Valentin Wüstholz <wuestholz@gmail.com>
Date: Mon, 7 Mar 2016 18:25:13 -0600
Subject: Add support for weights on soft assumes.

---
 Source/Provers/SMTLib/SMTLibLineariser.cs  |  2 +-
 Source/Provers/SMTLib/TypeDeclCollector.cs |  4 ++--
 Source/VCExpr/VCExprAST.cs                 | 11 ++++++++++-
 Source/VCGeneration/Wlp.cs                 |  5 +++--
 4 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/Source/Provers/SMTLib/SMTLibLineariser.cs b/Source/Provers/SMTLib/SMTLibLineariser.cs
index 6df44c2f..06554fcb 100644
--- a/Source/Provers/SMTLib/SMTLibLineariser.cs
+++ b/Source/Provers/SMTLib/SMTLibLineariser.cs
@@ -281,7 +281,7 @@ namespace Microsoft.Boogie.SMTLib
           Linearise(node[1], options);
           return true;
         }
-        if (node.Op.Equals(VCExpressionGenerator.SoftOp))
+        if (node.Op is VCExprSoftOp)
         {
           Linearise(node[1], options);
           return true;
diff --git a/Source/Provers/SMTLib/TypeDeclCollector.cs b/Source/Provers/SMTLib/TypeDeclCollector.cs
index 72540c9c..d911ce58 100644
--- a/Source/Provers/SMTLib/TypeDeclCollector.cs
+++ b/Source/Provers/SMTLib/TypeDeclCollector.cs
@@ -210,10 +210,10 @@ void ObjectInvariant()
 
       if (node.Op is VCExprStoreOp) RegisterStore(node);
       else if (node.Op is VCExprSelectOp) RegisterSelect(node);
-      else if (node.Op.Equals(VCExpressionGenerator.SoftOp)) {
+      else if (node.Op is VCExprSoftOp) {
         var exprVar = node[0] as VCExprVar;
         AddDeclaration(string.Format("(declare-fun {0} () Bool)", exprVar.Name));
-        AddDeclaration(string.Format("(assert-soft {0} :weight 1)", exprVar.Name));
+        AddDeclaration(string.Format("(assert-soft {0} :weight {1})", exprVar.Name, ((VCExprSoftOp)node.Op).Weight));
       } else if (node.Op.Equals(VCExpressionGenerator.NamedAssumeOp)) {
         var exprVar = node[0] as VCExprVar;
         AddDeclaration(string.Format("(declare-fun {0} () Bool)", exprVar.Name));
diff --git a/Source/VCExpr/VCExprAST.cs b/Source/VCExpr/VCExprAST.cs
index a58cfb7f..2c77a252 100644
--- a/Source/VCExpr/VCExprAST.cs
+++ b/Source/VCExpr/VCExprAST.cs
@@ -344,7 +344,6 @@ namespace Microsoft.Boogie {
     public static readonly VCExprOp MinimizeOp = new VCExprCustomOp("minimize##dummy", 2, Type.Bool);
     public static readonly VCExprOp MaximizeOp = new VCExprCustomOp("maximize##dummy", 2, Type.Bool);
     public static readonly VCExprOp NamedAssumeOp = new VCExprCustomOp("named_assume##dummy", 2, Type.Bool);
-    public static readonly VCExprOp SoftOp = new VCExprCustomOp("soft##dummy", 2, Type.Bool);
 
     public VCExprOp BoogieFunctionOp(Function func) {
       Contract.Requires(func != null);
@@ -1570,6 +1569,16 @@ namespace Microsoft.Boogie.VCExprAST {
     }
   }
 
+  public class VCExprSoftOp : VCExprCustomOp
+  {
+    public readonly int Weight;
+
+    public VCExprSoftOp(int weight) : base("soft##dummy", 2, Microsoft.Boogie.Type.Bool)
+    {
+      Weight = weight;
+    }
+  }
+
   public class VCExprCustomOp : VCExprOp {
     public readonly string/*!*/ Name;
     int arity;
diff --git a/Source/VCGeneration/Wlp.cs b/Source/VCGeneration/Wlp.cs
index 07db709d..d18c544a 100644
--- a/Source/VCGeneration/Wlp.cs
+++ b/Source/VCGeneration/Wlp.cs
@@ -199,10 +199,11 @@ namespace VC {
           expr = gen.Function(VCExpressionGenerator.NamedAssumeOp, v, gen.ImpliesSimp(v, expr));
         }
         var soft = QKeyValue.FindBoolAttribute(ac.Attributes, "soft");
-        if (soft && aid != null)
+        var softWeight = QKeyValue.FindIntAttribute(ac.Attributes, "soft", 0);
+        if ((soft || 0 < softWeight) && aid != null)
         {
           var v = gen.Variable("soft$$" + aid, Microsoft.Boogie.Type.Bool);
-          expr = gen.Function(VCExpressionGenerator.SoftOp, v, gen.ImpliesSimp(v, expr));
+          expr = gen.Function(new VCExprSoftOp(Math.Max(softWeight, 1)), v, gen.ImpliesSimp(v, expr));
         }
         return MaybeWrapWithOptimization(ctxt, gen, ac.Attributes, gen.ImpliesSimp(expr, N));
       } else {
-- 
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