title: LLVM IR limitations
body: <p>I am looking to generate LLVM-IR code from C code and was wondering how well is the IR generation for functions in:</p>
  
  <p>stdio.h, string.h, stdlib.h and generally the standard memory based functions such as malloc, calloc, since I have not been able to find most of the common functions in: </p>
  
  <p><a href="http://llvm.org/docs/LangRef.html" rel="nofollow">http://llvm.org/docs/LangRef.html</a> and was wondering about the limitations of this representation and whether I might be required to add my own intrinsics just to deal with standard/most popular c functions.</p>
  
  <p>I am looking to change the code at runtime, so was wondering which kind of approach will give me the most flexibility eg: Manipulate the code at AST level instead.</p>
  
  <p>Thanks</p>