save progress

src/BinaryIndex/__Libraries/StellaOps.BinaryIndex.Builders/IFunctionFingerprintExtractor.cs

@@ -1,3 +1,5 @@
+using StellaOps.BinaryIndex.Semantic;
+
 namespace StellaOps.BinaryIndex.Builders;
 
 /// <summary>
@@ -109,6 +111,12 @@ public sealed record FunctionFingerprint
     /// Source line number if debug info available.
     /// </summary>
     public int? SourceLine { get; init; }
+
+    /// <summary>
+    /// Semantic fingerprint for enhanced similarity comparison.
+    /// Uses IR-level analysis for resilience to compiler optimizations.
+    /// </summary>
+    public Semantic.SemanticFingerprint? SemanticFingerprint { get; init; }
 }
 
 /// <summary>

src/BinaryIndex/__Libraries/StellaOps.BinaryIndex.Builders/IPatchDiffEngine.cs

@@ -192,25 +192,42 @@ public sealed record HashWeights
     /// <summary>
     /// Weight for basic block hash comparison.
     /// </summary>
-    public decimal BasicBlockWeight { get; init; } = 0.5m;
+    public decimal BasicBlockWeight { get; init; } = 0.4m;
 
     /// <summary>
     /// Weight for CFG hash comparison.
     /// </summary>
-    public decimal CfgWeight { get; init; } = 0.3m;
+    public decimal CfgWeight { get; init; } = 0.25m;
 
     /// <summary>
     /// Weight for string refs hash comparison.
     /// </summary>
-    public decimal StringRefsWeight { get; init; } = 0.2m;
+    public decimal StringRefsWeight { get; init; } = 0.15m;
+
+    /// <summary>
+    /// Weight for semantic fingerprint comparison.
+    /// Only used when both fingerprints have semantic data.
+    /// </summary>
+    public decimal SemanticWeight { get; init; } = 0.2m;
 
     /// <summary>
     /// Default weights.
     /// </summary>
     public static HashWeights Default => new();
 
+    /// <summary>
+    /// Weights without semantic analysis (traditional mode).
+    /// </summary>
+    public static HashWeights Traditional => new()
+    {
+        BasicBlockWeight = 0.5m,
+        CfgWeight = 0.3m,
+        StringRefsWeight = 0.2m,
+        SemanticWeight = 0.0m
+    };
+
     /// <summary>
     /// Validates that weights sum to 1.0.
     /// </summary>
-    public bool IsValid => Math.Abs(BasicBlockWeight + CfgWeight + StringRefsWeight - 1.0m) < 0.001m;
+    public bool IsValid => Math.Abs(BasicBlockWeight + CfgWeight + StringRefsWeight + SemanticWeight - 1.0m) < 0.001m;
 }

src/BinaryIndex/__Libraries/StellaOps.BinaryIndex.Builders/PatchDiffEngine.cs

@@ -1,4 +1,5 @@
 using Microsoft.Extensions.Logging;
+using StellaOps.BinaryIndex.Semantic;
 
 namespace StellaOps.BinaryIndex.Builders;
 
@@ -202,6 +203,16 @@ public sealed class PatchDiffEngine : IPatchDiffEngine
             matchedWeight += weights.StringRefsWeight;
         }
 
+        // Include semantic fingerprint similarity if available
+        if (weights.SemanticWeight > 0 &&
+            a.SemanticFingerprint is not null &&
+            b.SemanticFingerprint is not null)
+        {
+            totalWeight += weights.SemanticWeight;
+            var semanticSimilarity = ComputeSemanticSimilarity(a.SemanticFingerprint, b.SemanticFingerprint);
+            matchedWeight += weights.SemanticWeight * semanticSimilarity;
+        }
+
         // Size similarity bonus (if sizes are within 10%, add small bonus)
         if (a.Size > 0 && b.Size > 0)
         {
@@ -216,6 +227,86 @@ public sealed class PatchDiffEngine : IPatchDiffEngine
         return totalWeight > 0 ? matchedWeight / totalWeight : 0m;
     }
 
+    private static decimal ComputeSemanticSimilarity(
+        Semantic.SemanticFingerprint a,
+        Semantic.SemanticFingerprint b)
+    {
+        // Check for exact hash match first
+        if (a.HashEquals(b))
+        {
+            return 1.0m;
+        }
+
+        // Compute weighted similarity from components
+        decimal graphSim = ComputeHashSimilarity(a.GraphHash, b.GraphHash);
+        decimal opSim = ComputeHashSimilarity(a.OperationHash, b.OperationHash);
+        decimal dfSim = ComputeHashSimilarity(a.DataFlowHash, b.DataFlowHash);
+        decimal apiSim = ComputeApiCallSimilarity(a.ApiCalls, b.ApiCalls);
+
+        // Weights: graph structure 40%, operation sequence 25%, data flow 20%, API calls 15%
+        return (graphSim * 0.40m) + (opSim * 0.25m) + (dfSim * 0.20m) + (apiSim * 0.15m);
+    }
+
+    private static decimal ComputeHashSimilarity(byte[] hashA, byte[] hashB)
+    {
+        if (hashA.Length == 0 || hashB.Length == 0)
+        {
+            return 0m;
+        }
+
+        if (hashA.AsSpan().SequenceEqual(hashB))
+        {
+            return 1.0m;
+        }
+
+        // Count matching bits (Hamming similarity)
+        int matchingBits = 0;
+        int totalBits = hashA.Length * 8;
+        int len = Math.Min(hashA.Length, hashB.Length);
+
+        for (int i = 0; i < len; i++)
+        {
+            byte xor = (byte)(hashA[i] ^ hashB[i]);
+            matchingBits += 8 - PopCount(xor);
+        }
+
+        return (decimal)matchingBits / totalBits;
+    }
+
+    private static int PopCount(byte value)
+    {
+        int count = 0;
+        while (value != 0)
+        {
+            count += value & 1;
+            value >>= 1;
+        }
+        return count;
+    }
+
+    private static decimal ComputeApiCallSimilarity(
+        System.Collections.Immutable.ImmutableArray<string> apiCallsA,
+        System.Collections.Immutable.ImmutableArray<string> apiCallsB)
+    {
+        if (apiCallsA.IsEmpty && apiCallsB.IsEmpty)
+        {
+            return 1.0m;
+        }
+
+        if (apiCallsA.IsEmpty || apiCallsB.IsEmpty)
+        {
+            return 0.0m;
+        }
+
+        var setA = new HashSet<string>(apiCallsA, StringComparer.Ordinal);
+        var setB = new HashSet<string>(apiCallsB, StringComparer.Ordinal);
+
+        var intersection = setA.Intersect(setB).Count();
+        var union = setA.Union(setB).Count();
+
+        return union > 0 ? (decimal)intersection / union : 0m;
+    }
+
     /// <inheritdoc />
     public IReadOnlyDictionary<string, string> FindFunctionMappings(
         IReadOnlyList<FunctionFingerprint> vulnerable,

src/BinaryIndex/__Libraries/StellaOps.BinaryIndex.Builders/StellaOps.BinaryIndex.Builders.csproj

@@ -20,5 +20,6 @@
   <ItemGroup>
     <ProjectReference Include="../StellaOps.BinaryIndex.Core/StellaOps.BinaryIndex.Core.csproj" />
     <ProjectReference Include="../StellaOps.BinaryIndex.Fingerprints/StellaOps.BinaryIndex.Fingerprints.csproj" />
+    <ProjectReference Include="../StellaOps.BinaryIndex.Semantic/StellaOps.BinaryIndex.Semantic.csproj" />
   </ItemGroup>
 </Project>