EBC, The EFI Byte Code, is a UEFI feature that supports Intel (Itanium, x86, and x64) instructions in a single bytecode. The Intel C Compiler can target EBC, and UEFI drivers can use EBC instead of native drivers, to save space (1 binary, instead of 3).
The other week I gave a firmware security tools talk at BlackLodgeResearch.org, and Vincent Zimmer of Intel showed up. I had a slide complaining that EBC is only supported by Intel C Compiler, a commercial-only product, and that the UEFI Forum should fund a ‘summer-of-code’-style effort to get EBC into GCC or LLVM CLang. After the talk, Vincent mentioned that ICC had to do a bit of unexpected work to generate EBC, and would blog about it. Well, he did blog about it, a few days ago, just catching up to it, and describe the problem.
If you know of someone on the LLVM CLang or GCC project, please try to add a request for EBC support.
Not only would it be nice to have LLVM CLang work with EBC to have an alternative to ICC, and for LLBVM’s Klee fuzzer (to fuzz UEFI via OVMF), but ALSO because the Capstone Framework RE tool uses LLVM’s intermediate form and would then get EBC support!!
Today, radare2, another RE tool, already has EBC support.
If technically possible, it might be nice if ARM added AArch32 and AArch64 support, and EBC support in their compiler, so that EBC could actually target all UEFI platforms with a single blob. ARM/Linaro already has something that appears to overlap in some ways:
Also, there’s a C#/IL to EBC translation project on Github. If you get it to work, let me know!