# Function-Range Hashing and Symbol Mapping

## Module
BinaryIndex

## Status
IMPLEMENTED

## Description
Multi-backend disassembly (Iced, B2R2) with function-range normalization for symbol-level binary proof.

## Implementation Details
- **Modules**: `src/BinaryIndex/__Libraries/StellaOps.BinaryIndex.Builders/`, `src/BinaryIndex/__Libraries/StellaOps.BinaryIndex.Diff/`
- **Key Classes**:
  - `IFunctionFingerprintExtractor` (`src/BinaryIndex/__Libraries/StellaOps.BinaryIndex.Builders/IFunctionFingerprintExtractor.cs`) - extracts function-range fingerprints from disassembled binaries
  - `FunctionDiffer` (`src/BinaryIndex/__Libraries/StellaOps.BinaryIndex.Diff/FunctionDiffer.cs`) - compares function fingerprints with semantic analysis support; computes call-graph edge diffs
  - `FunctionRenameDetector` (`src/BinaryIndex/__Libraries/StellaOps.BinaryIndex.Diff/FunctionRenameDetector.cs`) - detects renamed functions by comparing fingerprint similarity
  - `PatchDiffEngine` (`src/BinaryIndex/__Libraries/StellaOps.BinaryIndex.Builders/PatchDiffEngine.cs`) - builder-level patch diff engine
  - `FingerprintClaimModels` (`src/BinaryIndex/__Libraries/StellaOps.BinaryIndex.Builders/FingerprintClaimModels.cs`) - `FingerprintClaim` and `FingerprintClaimEvidence` records
- **Models**: `FingerprintModels` (`src/BinaryIndex/__Libraries/StellaOps.BinaryIndex.Analysis/Models/FingerprintModels.cs`) - `FunctionFingerprint` with hash, size, call edges
- **Disassembly Backends**: `B2R2DisassemblyPlugin` (ARM/x86/x64/AArch64), `IcedDisassemblyPlugin` (x86/x64)

## E2E Test Plan
- [ ] Extract function fingerprints from an ELF binary and verify hash consistency for identical functions
- [ ] Verify function-range normalization produces same hash across compiler optimization levels when function logic is identical
- [ ] Verify `FunctionDiffer` correctly identifies added, removed, and modified functions
- [ ] Verify `FunctionRenameDetector` matches renamed functions based on fingerprint similarity threshold
- [ ] Verify `FingerprintClaim` evidence links correctly to Build-ID and function IDs
- [ ] Verify multi-backend consistency: same binary produces matching fingerprints via B2R2 and Iced