Changes in driver/as.cc [92f413c:245a92c]

File:

• driver/as.cc (modified) (2 diffs)

driver/as.cc

@@ -5 +5 @@
 // file "LICENCE" distributed with Cforall.
 // 
-// as.c -- 
+// as.c -- map assembler file, scan for debug information. If found, expand file by one character and insert Cforall
+//         language code on the N line from the start of the debug information.
 // 
 // Author           : Peter A. Buhr
 // Created On       : Wed Aug  1 10:49:42 2018
 // Last Modified By : Peter A. Buhr
-// Last Modified On : Wed Aug 22 17:30:24 2018
-// Update Count     : 93
+// Last Modified On : Sat Sep  8 08:40:16 2018
+// Update Count     : 97
 // 
 
@@ -43 +44 @@
         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 ( size ) {                                                                           // cannot map 0 sized file
+                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 ); };
+                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
+                        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 ); };
+                        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
+                        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';
+                        *(cursor) = '2';                                                        // replace C language value with CFA
+                        *(cursor + 1) = '5';
+                } // if
+
+                if ( munmap( start, size ) ) { perror( "munmap" ); exit( EXIT_FAILURE ); }; // update on disk
         } // if
-
-        if ( munmap( start, size ) ) { perror( "munmap" ); exit( EXIT_FAILURE ); }; // update on disk
 
         argv[0] = "as";