fix: HLIL OperationOperands undercounts + ROR bogus Carry#26
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The OperationOperands count table in Struct/BNHighLevelILInstruction.cs sized the per-instruction RawOperands[] array too small for 21 operations, so accessing the affected typed-accessor properties threw IndexOutOfRangeException at runtime. The undercounts fell into groups: - TwoOperandWithCarry ops (ADC/SBB/RLC/RRC) omitted the carry operand (2->3) - SSA stores omitted the dest memory-version slot (VAR_INIT_SSA, ASSIGN_MEM_SSA, ASSIGN_UNPACK_MEM_SSA, CALL_SSA, INTRINSIC_SSA, SYSCALL_SSA) - SSAVariable-occupying ops omitted the version's second raw slot (FORCE_VER_SSA, ASSERT_SSA, VAR_PHI) - Phi/control ops omitted loop and phi operands (MEM_PHI, WHILE_SSA, DO_WHILE_SSA, FOR_SSA, CASE, ASSIGN_UNPACK) - Plain non-SSA force/assert omitted their second operand (FORCE_VER, ASSERT) HLIL_ROR additionally exposed a bogus Carry property that read operands[2] past its two operands -- C++ ROR is TwoOperandInstruction (no carry; only ADC/SBB/RLC/RRC are TwoOperandWithCarry). Removed. Counts verified 1:1 against binaryninja-api/highlevelilinstruction.h raw operand layouts; SSAVariable occupies two raw slots (variable, version).
This was referenced Jul 8, 2026
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#41) Mirror Python HighLevelILInstruction.detailed_operands / operands / traverse (highlevelil.py:795/786/802). A static descriptor table (operation -> named, typed operands) drives a kind-dispatched reader; Operands and Traverse derive from it, exactly as in Python. - HighLevelILOperand: enum Kind + readonly Operand/Descriptor structs. - HighLevelILDetailedOperandsTable: 114-op descriptor table generated from the Python detailed_operands overrides, abstract bases expanded to concrete ops. - HighLevelILInstruction: GetOperandAsInteger, virtual DetailedOperands, ReadDetailedOperandByKind (SSA var + constant data occupy two raw slots), Operands, generic Traverse<T> (DFS, shallow blacklist matches Python). - HLILVariableDeclare: expose the .Variable accessor (the one missing accessor). Divergence from Python (intentional, documented in the table header): HLIL_ROR omits the "carry" operand -- Python's HighLevelILRor inherits CarryBase but the core (highlevelilinstruction.cpp:189) defines ROR with only {left,right}, so Python's Ror.carry reads a non-existent slot. C# follows the core (OperationOperands = 2, matching PR #26's removal of the bogus Carry accessor). E2E (harness, not in this repo): DetailedOperands parity vs the Python spec for ADD/STRUCT_FIELD/CONST(+PTR/FLOAT); Operands + Traverse; full cat.bndb sweep no-throw; static consistency test reflecting over the table + OperationOperands catches out-of-bounds indices (the ROR bug above was found + fixed by it). 76/76 pass.
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Problem
The
OperationOperandscount table inStruct/BNHighLevelILInstruction.cssizes each instruction'sRawOperands[]array. 21 entries undercounted their operands, so accessing the affected typed-accessor property (e.g.DestMemoryVersion,SourceMemoryVersion,Carry,Loop,Cond) threwIndexOutOfRangeExceptionat runtime — the operand was never readable.HLIL_RORadditionally exposed a bogusCarryproperty readingoperands[2]past its two operands (C++RORisTwoOperandInstruction; onlyADC/SBB/RLC/RRCareTwoOperandWithCarry).Root cause
Counts verified 1:1 against
binaryninja-api/highlevelilinstruction.hraw operand layouts. The misses fall into groups:2→3This is the systematic-miscount cluster flagged from PR #24 (which fixed only STRUCT_FIELD/DEREF_FIELD/DEREF_FIELD_SSA).
Changes
Struct/BNHighLevelILInstruction.cs: 21 count bumps in theOperationOperandstable, each with an operand-list comment.HighLevelIL/HLILRotateRight.cs: removed bogusCarryproperty.Verification
dotnet build -c Releaseclean.crash_audit.py, op→accessor switch): NO OOB after the fix (was 22 OOB).cat.bndbviaMustGetExpression, invokes each declared operand-accessor getter, asserts none throwsIndexOutOfRangeException.Scope
Same bug class likely exists in the MLIL and LLIL operand-count tables — follow-up PRs will address those. (Also noted: the cross-IL mapping properties
MediumLevelILs/LowLevelILsthrowIndexOutOfRangefor unmapped instructions — a separate latent bug, out of scope here.)