source: driver/as.cc @ ef2eade

// 
// Cforall Version 1.0.0 Copyright (C) 2015 University of Waterloo
//
// The contents of this file are covered under the licence agreement in the
// file "LICENCE" distributed with Cforall.
// 
// as.c -- 
// 
// Author           : Peter A. Buhr
// Created On       : Wed Aug  1 10:49:42 2018
// Last Modified By : Peter A. Buhr
// Last Modified On : Thu Aug  2 17:50:09 2018
// Update Count     : 90
// 

#include <cstdio>                                                                               // perror
#include <cstdlib>                                                                              // exit
#include <fcntl.h>                                                                              // open
#include <unistd.h>
#include <sys/stat.h>
#include <sys/mman.h>                                                                   // mmap
#include <string.h>

//#define __DEBUG_H__

int main( const int argc, const char * argv[] ) {
        #ifdef __DEBUG_H__
        for ( int i = 0; i < argc; i += 1 ) {
                cerr << argv[i] << endl;
        } // for
        #endif // __DEBUG_H__

        int fd = open( argv[argc - 1], O_RDWR );
        if ( fd < 0 ) { perror( "open" ); exit( EXIT_FAILURE ); };

        struct stat mystat = {};
        if ( fstat( fd, &mystat ) ) { perror( "fstat" ); exit( EXIT_FAILURE ); };
        off_t size = mystat.st_size;

        char * start = (char *)mmap( NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0 );
        if ( start == (void *)-1 ) { perror( "mmap" ); exit( EXIT_FAILURE ); };

        if ( char * cursor = strstr( start, ".Ldebug_info0:" ) ) { // debug information ?
                // Expand file by one byte to hold 2 character Cforall language code.
                if ( ftruncate( fd, size + 1 ) ) { perror( "ftruncate" ); exit( EXIT_FAILURE ); };

                for ( int i = 0; i < 8; i += 1 ) {                              // move N (magic) lines forward
                        cursor = strstr( cursor, "\n" ) + 1;
                } // for

                cursor -= 2;                                                                    // backup over "c\n" language value
                if ( *(cursor - 1) != 'x' ) { fprintf( stderr, "invalid C language code\n" ); exit( EXIT_FAILURE ); };

                memmove( cursor + 2, cursor + 1, start + size - cursor - 1 ); // move remaining text 1 character right

                *(cursor) = '2';                                                                // replace C language value with CFA
                *(cursor + 1) = '5';
        } // if

        if ( munmap( start, size ) ) { perror( "munmap" ); exit( EXIT_FAILURE ); }; // update on disk

        argv[0] = "as";
        execvp( argv[0], (char * const *)argv );                        // should not return
        perror( "CFA Translator error: cpp level, execvp" );
        exit( EXIT_FAILURE );                                                           // tell gcc not to go any further
} // main

// Local Variables: //
// tab-width: 4 //
// mode: c++ //
// compile-command: "g++ -Wall -Wextra as.c -o as" //
// End: //