[LLVMdev] library functions

[George Baah]

I see that some of the system header-file definitions have the internal
keyword.
For example,

define internal void @__cxx_global_var_init() section
"__TEXT,__StaticInit,regular,pure_instructions" {
entry:
  call void @_ZNSt8ios_base4InitC1Ev(%"class.std::ios_base::Init"*
@_ZStL8__ioinit)
  %0 = call i32 @__cxa_atexit(void (i8*)* bitcast (void
(%"class.std::ios_base::Init"*)* @_ZNSt8ios_base4InitD1Ev to void (i8*)*),
i8* getelementptr
inbounds (%"class.std::ios_base::Init"* @_ZStL8__ioinit, i32 0, i32 0), i8*
bitcast (i8** @__dso_handle to i8*))
  ret void
}

On Mon, May 23, 2011 at 2:24 PM, John Criswell <criswell at illinois.edu>wrote:

>  On 5/23/11 1:05 PM, George Baah wrote:
>
> Hi,
>  I am writing a pass which is supposed to ignore library functions. Is
> there a way to
> distinguish functions declared and defined by a developer from non-local
> functions (library functions)?
> Thanks.
>
>
> There is no reliable way to do this, but there are several heuristics that
> will probably work well in practice.
>
> When analyzing a program, any function that is defined (i.e., has a
> function body) most likely came from the program's source code.  The
> exception will be functions declared in system header files or C/C++ library
> header files.
>
> Any function that is declared but not defined (i.e., has no function body)
> is either a function that is defined in another translation unit (i.e.,
> another source file) or defined in a system or language library (e.g.,
> libc).  It is, in general, not possible to distinguish between the two
> situations, although if you've linked your entire program into a single
> bitcode file, the only external functions are coming from library functions.
>
> -- John T.
>
>
>  George
>
>
> _______________________________________________
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>
>
>
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