Load files on demand, support multiple source files

command.c

@@ -22,7 +22,7 @@ command_step(struct mi_process proc)
     print_current_instruction(proc);
     struct mi_registers regs = get_process_registers(proc);
     struct mi_sourcepoint *sp = pc_to_sourcepoint(proc, regs.rip - proc.base_address);
-    print_current_line(proc, sp->line);
+    print_sourcepoint(proc, sp);
 #endif
 }
 
@@ -68,7 +68,7 @@ command_next(struct mi_process proc)
         // TODO: skip call, repXXX, etc
     } while (next_sp->line == sp->line);
     
-    print_current_line(proc, next_sp->line);
+    print_sourcepoint(proc, next_sp);
 }
 
 static void
@@ -76,7 +76,7 @@ command_list(struct mi_process proc)
 {
     struct mi_registers regs = get_process_registers(proc);
     struct mi_sourcepoint *sp = pc_to_sourcepoint(proc, regs.rip - proc.base_address);
-    print_current_line(proc, sp->line);
+    print_sourcepoint(proc, sp);
 }
 
 static void

common.h

@@ -31,6 +31,11 @@ typedef int64_t s64;
 
 #include "elf_dwarf.h"
 
+struct mi_buffer {
+    u8 *data;
+    u64 size;
+};
+
 struct mi_sourcepoint {
     u64 pc;
     int line;
@@ -41,9 +46,6 @@ struct mi_sourcepoint {
 struct mi_process {
     pid_t pid;
     
-    char *source;
-    u64 source_size;
-    
     u8 *elf;
     u64 elf_size;
     
@@ -52,6 +54,10 @@ struct mi_process {
     
     struct mi_sourcepoint *sp_table;
     int sp_count;
+    
+    char **source_file_names;
+    struct mi_buffer *source_files;
+    int source_file_count;
 };
 
 struct mi_registers {

dwarf.c

@@ -295,7 +295,7 @@ find_subroutine_offset(u8 *file, u64 header_size, u8 address_size,
 }
 
 static void
-construct_line_number_table(u8 *file, struct mi_sourcepoint *dest, int *dest_size)
+construct_line_number_table(u8 *file, struct mi_sourcepoint *dest, char **dest_files, int *dest_size, int *dest_files_size)
 {
     u64 dl_offset = get_section_offset(file, ".debug_line");
     
@@ -331,9 +331,13 @@ is followed by a single null byte." */
     
     p = file + dl_offset;
     while (*p != 0) {
+        /* null-terminated string */
+        if (dest_files) {
+            dest_files[nfiles] = (char *) p;
+        }
+        
         ++nfiles;
         
-        /* null-terminated string */
         while (*p != 0) {
             ++p;
         }
@@ -350,33 +354,8 @@ is followed by a single null byte." */
         p += offset;
     }
     
-    header.files = malloc(nfiles * sizeof(struct dwarf_debug_line_file_info));
-    header.nfiles = nfiles;
-    
-    struct dwarf_debug_line_file_info *f = header.files;
-    
-    p = file + dl_offset;
-    while (*p != 0) {
-        
-        /* null-terminated string */
-        f->name = (char *) p;
-        
-        while (*p != 0) {
-            ++p;
-        }
-        
-        ++p;
-        
-        u64 offset = 0;
-        u32 dummy = 0;
-        
-        offset += decode_leb128(p, &f->directory_index);
-        offset += decode_leb128(p, &f->time_modified);
-        offset += decode_leb128(p, &f->file_size);
-        
-        p += offset;
-        
-        ++f;
+    if (dest_files_size) {
+        *dest_files_size = nfiles;
     }
     
     dl_offset = p - file + 1;
@@ -618,7 +597,7 @@ is followed by a single null byte." */
         
     } while (opcode_extended != DW_LNE_end_sequence);
     
-    if (!dest) {
+    if (dest_size) {
         *dest_size = pc_count;
     }
 }

main.c

@@ -28,9 +28,11 @@ main(int argc, char *argv[])
     printf("> ");
     fflush(stdout);
     
-    construct_line_number_table(process.elf, 0, &process.sp_count);
+    construct_line_number_table(process.elf, 0, 0, &process.sp_count, &process.source_file_count);
     process.sp_table = malloc(process.sp_count * sizeof(struct mi_sourcepoint));
-    construct_line_number_table(process.elf, process.sp_table, 0);
+    process.source_file_names = malloc(process.source_file_count * sizeof(char *));
+    process.source_files = malloc(process.source_file_count * sizeof(char *));
+    construct_line_number_table(process.elf, process.sp_table, process.source_file_names, 0, 0);
     
     while ((command_length = getline(&command, &max_command_length, stdin))) {
         if (0 == strncmp(command, "exit\n", command_length) || 0 == strncmp(command, "q\n", command_length)) {

util.c

@@ -22,15 +22,44 @@ print_word_at_address(int child, u64 address)
     printf("word at %#018lx: {%x %x %x %x}\n", address, nb[0], nb[1], nb[2], nb[3]);
 }
 
+static struct mi_buffer
+read_file_mmap(char *path)
+{
+    struct mi_buffer result = { 0 };
+    
+    struct stat s;
+    int fd = open(path, O_RDONLY);
+    assert(fd != -1);
+    fstat(fd, &s);
+    
+    result.data = mmap(0, s.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
+    result.size = s.st_size;
+    
+    printf("mmap()-ed %ld bytes (%s)\n", result.size, path);
+    
+    close(fd);
+    
+    return(result);
+}
+
 static void
-print_current_line(struct mi_process proc, u64 line)
+print_sourcepoint(struct mi_process proc, struct mi_sourcepoint *sp)
 {
-    char *source = proc.source;
-    u64 size = proc.source_size;
-    u64 current_line = 1;
+    // NOTE: sourcepoint file indices are 1-based
+    if (proc.source_files[sp->file - 1].data == 0) {
+        char *path = proc.source_file_names[sp->file - 1];
+        struct mi_buffer file = read_file_mmap(path);
+        proc.source_files[sp->file - 1] = file;
+    }
+    
+    struct mi_buffer file = proc.source_files[sp->file - 1];
+    
+    char *source = (char *) file.data;
+    u64 size = file.size;
+    int current_line = 1;
     
     for (u32 i = 0; i < size; ++i) {
-        if (current_line == line) {
+        if (current_line == sp->line) {
             int len = 0;
             int start = 0;
             int leading = 1;
@@ -84,35 +113,10 @@ process_create(char *path)
         }
     }
     
-    u64 source_size;
-    u64 elf_size;
-    u8 *elf;
-    char *source;
-    struct stat s;
-    int fd;
-    
-    {
-        fd = open(path, O_RDONLY);
-        assert(fd != -1);
-        fstat(fd, &s);
-        elf_size = s.st_size;
-        elf = mmap(0, s.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
-        close(fd);
-    }
-    
-    {
-        fd = open("/code/trace-test/traceme.c", O_RDONLY); // TODO
-        assert(fd != -1);
-        fstat(fd, &s);
-        source_size = s.st_size;
-        source = mmap(0, source_size, PROT_READ, MAP_PRIVATE, fd, 0);
-        close(fd);
-    }
+    struct mi_buffer file = read_file_mmap(path);
     
-    result.elf = elf;
-    result.elf_size = elf_size;
-    result.source = source;
-    result.source_size = source_size;
+    result.elf = file.data;
+    result.elf_size = file.size;
     result.pid = pid;
     
     return(result);