Balancing performance and productivity for the development of dynamic binary instrumentation tools: a case study on Arm systems

Dynamic Binary Instrumentation (DBI) is a well-established approach for analysing the execution of applications at the level of machine code. DBI frameworks implement a runtime system capable of modifying running applications without access to their source code. These frameworks provide APIs used by DBI tools to plug in their specific analysis and instrumentation routines. However, the dynamic instrumentation needed by these DBI tools is either challenging to implement, and/or introduces a significant performance overhead. An added complexity beyond the well studied scenario of x86 and x86-64, is that state-of-the-art Arm systems (i.e. Arm v8) introduced a distinct 64-bit execution mode with a new redesigned instruction set. Thus, Arm v8 is a computer architecture which contains three instruction sets. This further complicates the development of DBI tools which can work for both 32-bit Arm (includes the A32 and T32 instruction sets), and 64-bit (the A64 instruction set). This paper presents the design of a novel DBI framework API that provides support both for portable (across A32, T32 and A64), and for native-code-level analysis and instrumentation, which can be intermixed freely. This API allows DBI tool developers to balance performance and productivity at a fine-grain level. The API is implemented on top of the MAMBO DBI system.