Philipp Klaus Krause via llvm-dev
2016-Sep-15 15:11 UTC
[llvm-dev] What's the easisest way to tell clang about type sizes and alignment?
To see the benefit of some optimization passes in LLVM for certain architectures, I'd like to compile C or C++ code for a target where a C compiler (SDCC) already exists. I guess the easiest way would be to use clang -S -emit-llvm then the optimization passes then the C backend (probably much easier than writing code to translate LLVM IR to SDCC iCode). There is a version of the C backend on GitHub for LLVM 3.7. I have looked at the output from that, and guess that with a few small fixes to make the C backend emit something more like proper C (instead of GCC/MSVC-isms) it should be useable with SDCC. But clang needs to know about the sizes and alignment of the C types (after all I don't want my int to become an expensive 32-bit wide 32-bit aligned thing inside clang). Is there an easy way to do so? Philipp