A CIL Tutorial - Department of Computer Science - ETH Zürich

CHAPTER 4. INSTRUMENTATION 39
method vstmt (s : stmt) =
let action s =
match s.skind with
| Loop(b, loc, co, bo) →
let counter = makeTempVar fd intType in
let ss, cis, is, es = makeInstrStmts counter loc in
b.bstmts ← is :: b.bstmts;
let nb = mkBlock [ss; cis; mkStmt s.skind; es] in
s.skind ← Block nb;
s
| → s
in
ChangeDoChildrenPost(s, action)
end
The function processFunction applies the loopInstrumenterClass to a function.
let processFunction (fd : fundec) (loc : location) : unit =
let vis = new loopInstrumenterClass fd in
ignore(visitCilFunction vis fd)
The function tut4 is the entry point in the module. It applies processFunction to every function
in a file.
let tut4 (f : file) : unit =
initTutFunctions f;
iterGlobals f (onlyFunctions processFunction)
Now we have added a bunch of function calls to the code. Several questions remain:
• Where are these functions dened? In ciltut-lib/src/tut4.c
• How does that le get built? We use cmake to congure and build the library libciltut.
The build of the library can be adjusted by modifying the CMakeLists.txt les under the
ciltut-lib directory. The Makefile generated by cmake is invoked from the root Makefile
when ciltutcc is built.
• How does that library get linked in to something that ciltutcc is building? There is a
Perl script in lib/Ciltut.pm that wraps up this OCaml program to make it look like gcc
(and a couple other compilers). It has a function called processArguments where we add the
library to a list in @{$self → {CILTUTLIBS}}. When this Perl script detects that it is being
used for the link stage of a build, it adds libciltut.a to the list of object les to link in.