This is a simple C++ program, for which we have provided a custom implementation of a function. Full code is provided here
Produce the ll file
Below is the C++ program that we are going to use(src ll file)
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
void usage() {
puts("Usage : message [-dialog] \"title\" \"message\"");
exit(-1);
};
void dialogBox(char* title , char* message) {
puts("Dialog:");
puts(title);
puts(message);
};
void console(char* title , char* message) {
puts(title);
puts(message);
};
int main (int argc,char **argv) {
int base =0;
int dialog=0;
char *title;
char *message;
switch (argc) {
case 3 :
if (strcmp("-dialog",argv[1])) {
title =argv[1];
message=argv[2] ;
console(title,message);
} else {
usage();
}
break;
case 4 :
if (!strcmp("-dialog",argv[1])) {
title =argv[2];
message=argv[3];
dialogBox(title,message);
} else {
usage();
}
break;
default :
usage();
break;
}
return 0;
}
Using the below command line the ll file was generated
llvm-g++ message.cc -S --emit-llvm -o message.ll
Compile with Proteus
Now using this ll file generate an executable jar. But we are going to provide an alternate implementation of dialogBox. First, we generated the source/classes/jar (note -force-name true is a useful option here).
Then, we found the function we wanted to substitute (_Z9dialogBoxPcS_.java) in the generated folder.
This is copied to source/org/proteus and and the static call method modified to modified (see below) to provide our alternate implementation.
/**
Custom version of the DialogBox Function
*/
package org.proteus;
import com.emt.proteus.lib.api.*;
import com.emt.proteus.runtime.api.*;
import javax.swing.*;
public final class _Z9dialogBoxPcS_ extends ImplementedFunction{
public _Z9dialogBoxPcS_() {
super("_Z9dialogBoxPcS_",2);
}
public int execute(int $title, int $message){
call($title, $message);
return 0;
}
public int execute(Env env, Frame caller, int return_addr, int return_width, int argc, int[] code, int pc) {
int $title = caller.getI32(code[pc]);
pc=pc+2;
argc--;
int $message = caller.getI32(code[pc]);
pc=pc+2;
argc--;
call($title, $message);
return pc;
}
public static void call(int $title, int $message){
JOptionPane.showMessageDialog(null,MainMemory.getString($message),MainMemory.getString($title),JOptionPane.PLAIN_MESSAGE);
} //End of Function
}
Now to combine our hand-coded class with the generated code we do the following (remember that we copied the java file to source/org/proteus folder).
java -jar Proteus.jar -source-path source message.ll
Run the generated java executable
The below will output the usage message
java -jar message.jar
The below will output to the console 'Title' and 'Message' (Note '--' to direct parameters to the generated code).
java -jar message.jar -- Title Message
The below will show a java JOptionPane with 'Title' and 'Message' (Note '--' to direct parameters to the generated code).
java -jar message.jar -- -dialog Title Message