duncantl / NativeCodeAnalysis

Code analysis tools for C/C++ using Rllvm and RCIndex to access code content

NativeCodeAnalysis

This is R-level code to query and analyze C and C++ code. It uses both the Rllvm and RCIndex packages to access aspects of the native code. This is in some ways analogous to the CodeAnalysis, codetools, and other packages for analyzing R code, but for native code.

It provides R-level functions rather than C/C++-level implementations such as with the excellent rchk tool that finds, e.g., PROTECT/UNPROTECT errors in C/C++ code. The reason for this choice is that writing R code is more time-efficient and makes the code more accessible and extensible to others.

The package provides protoypes for

• identifying the R type of the return from a .Call() or .External() call, including the types (and names) of the elements of a returned list (getRReturnTypes());
• inferring the types of the parameters of a .Call() or .External() routine based on how each parameter is
  • coerced (e.g. Rf_asReal()) or
  • accessed (e.g. INTEGER(x)[0] or VECTOR_ELT(x, 0)), or
  • used, e.g., SET_NAMES(ans, x);
• determining the length/dimension of an R object based on the code that constructs it or how it is used in the routine (inferLength() and inferParamTypes());
• finding the class of the return value (getReturnClass()).

We can also borrow information from the R code that calls a routine to see how it coerces the arguments to different types and what length/dimension information is available from that R code that we can utilize and/or validate when analyzing the C code.

Utilities

• examples/IRMakefile - stand-aside makefile that complements a package's Makevars file so that we can create the IR files from the .c/.cpp source files.

Documentation

• examples/Packages.xml - how to analyze C/C++ code in packages.
• examples/RInternalLLVM.xml - Rllvm approach to analyzing R base/internal code
• examples/RInternal.xml - RCIndex approach to analyzing R base/internal code
• tests/R_FunTab.xml - how to read the R_FunTab array in names.c that maps primitive/internal functions to C routines
• examples/toupper.md - analysis of the toupper() function as it relates to C code.