This is my first LLVM PASS exercise

my codes are modified from llvm-3.2.src/lib/Transforms/Hello/Hello.cpp

build

Makefile

$ make
clang -c mypass.cpp -o mypass.o `llvm-config --cppflags` -fPIC -fno-rtti
clang -shared mypass.o -o mypass.so `llvm-config --ldflags`

test

a test loop example

$ cat hello.c

#include <stdio.h>
#include <stdlib.h>

void myfun (void) {
    puts("enter myfunc()");
    for (int i = 0; i < 10; i++) {
        printf("QQ XD Orz %d\n", i);
    }
    puts("leave myfunc()");
}
int main (void) {
    puts("in main");
    myfun();
    puts("after myfunc()");
    return 0;
}

compile to llvm bitcode

$ clang -c -emit-llvm hello.c -o hello.bc

the behavior of hello.c

$ lli hello.bc

in main
enter myfunc()
QQ XD Orz 0
QQ XD Orz 1
QQ XD Orz 2
QQ XD Orz 3
QQ XD Orz 4
QQ XD Orz 5
QQ XD Orz 6
QQ XD Orz 7
QQ XD Orz 8
QQ XD Orz 9
leave myfunc()
after myfunc()

• use mypass to analysis it

$ opt -load ./mypass.so - mypass1 ./hello.bc -disable-output

my pass: (runOn) 'myfun'  
my pass: (runOn) 'main'

• use mypass2 to analysis it!

$ opt -load ./mypass.so -mypass2 ./hello.bc -disable-output

my pass2: (doInit)myfun
my pass2: (runOn), myParent = myfun
my pass2: (runOn), myParent = myfun
my pass2: (runOn), myParent = myfun
my pass2: (runOn), myParent = myfun
my pass2: (runOn), myParent = myfun
my pass2: (doFin)myfun
my pass2: (doInit)main
my pass2: (runOn), myParent = main
my pass2: (doFin)main