[llvm-dev] Runtime interception: design problem

[Mehdi Amini via llvm-dev]

> On May 25, 2016, at 6:05 AM, Pierre Gagelin via llvm-dev <llvm-dev at lists.llvm.org> wrote:
> 
> Hi everyone,
> 
> I am having troubles but this shouldn't be hard to solve for many people here. I am beginning a runtime feature for the BoundsChecking pass and I want to replace the libc malloc&free. I followed the design of AddressSanitizer (Asan) and tried to use the INTERCEPTOR macro from the interception.h file of compiler-rt library.
> 
> Here is the problem. The file I modify (BoundsCheking.cpp) is in lib/Transforms/Instrumentation/ and I can't include properly interception.h (which is in projects/compiler-rt/lib/interception/).

Something does not make sense to me here: lib/Transforms/... is about stuff that will transform/generate code, it does not contain code that will be part of the final binary. So this transform may generates calls to your runtime, but should not need the runtime to operate.

-- 
Mehdi



> I looked at the CMakeLists.txt and how other files included interception.h but they are all from compiler-rt lib directory.
> 
> I assume this is normal as runtime project should be developped under the correct directory but I don't see how this should be designed in order that the code optimized by BoundsCheking Pass uses my own malloc&free functions.
> 
> I spent quite some time on Asan runtime code and found that runtime could be initialized with a call to __asan_init() (function defined in asan_rtl.cc) from the instrumented code directly but I don't know if it's the only way to do it or how to reproduce it...
> 
> So to resume, I want to make my own malloc and free function to be called by the code I instrument with BoundsChecking. Any suggestion is welcome =)
> 
> Thanks,
> Pierre
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