Raising binaries to LLVM IR with MCTOLL (WIP paper)

Abstract

The need to analyze and execute binaries from legacy ISAs on new or different ISAs has been addressed in a variety of ways over the past few decades. Solutions using complementary static and dynamic binary translation techniques have been deployed in most real-world situations. As new ISAs are designed and legacy ISAs re-examined, the need for binary translation infrastructure re-emerges, and needs to be re- engineered all over again. Work is in progress with a goal to make such re-engineering efforts easier by using some of the software tools that would irrespectively be developed or available for a new or existing ISA. To that end, this paper presents a static binary raiser that translates binaries to LLVM IR. Native binaries for a new ISA are generated from the raised LLVM IR using the LLVM compiler backend. This technique enables development of a single raiser per legacy ISA, irrespective of the new target ISA. The result of such a raiser can then leverage compiler back-ends of new ISAs, thus simplifying the development of binary translator for the new ISA . This work leverages the existing LLVM infrastructure to implement a static raiser that currently supports raising x64 and Arm32 binaries to LLVM IR. The raiser is built as an LLVM tool – similar to llvm-objdump or clang and does not have any dependencies outside of those needed to build LLVM. This paper describes the phases of the raiser and gives the current status and limitations.