backtrace ("bt") command works (only if frame pointer is not ommited!)

command.c

@@ -126,4 +126,25 @@ static void
 command_kill(struct mi_process proc)
 {
     kill(proc.pid, SIGKILL);
+}
+
+static void
+command_backtrace(struct mi_process proc)
+{
+    struct mi_registers regs = get_process_registers(proc);
+    struct mi_function *func = get_function_around_pc(proc, regs.rip - proc.base_address);
+    
+    u64 fb = regs.rbp;
+    u64 return_address = ptrace(PTRACE_PEEKDATA, proc.pid, fb + 8, NULL);
+    
+    printf("%s: %#lx\n", func->name, regs.rip);
+    
+    for (int i = 0; i < 3; ++i) {
+        func = get_function_around_pc(proc, return_address - proc.base_address);
+        if (func) {
+            printf("%s: %#lx\n", func->name, regs.rip);
+        }
+        fb = ptrace(PTRACE_PEEKDATA, proc.pid, fb, NULL);
+        return_address = ptrace(PTRACE_PEEKDATA, proc.pid, fb + 8, NULL);
+    }
 }

common.h

@@ -43,13 +43,6 @@ struct mi_sourcepoint {
     int file;
 };
 
-struct mi_function {
-    char *name;
-    int comp_unit;
-    u64 low_pc;
-    u64 high_pc;
-};
-
 struct mi_sourcefile {
     char *filename;
     char *dir;
@@ -61,18 +54,15 @@ struct mi_variable {
     s64 location;
 };
 
-struct mi_block {
+struct mi_function {
     u64 low_pc;
     u64 high_pc;
-    
-    struct mi_variable variables[4]; // TODO
-    int var_count;
+    char *name;
+    int variables_from;
+    int variables_count;
 };
 
-struct mi_compunit {
-    u64 low_pc;
-    u64 high_pc;
-    
+struct mi_sourceinfo {
     struct mi_sourcepoint *sp_table;
     int sp_count;
     
@@ -83,17 +73,26 @@ struct mi_compunit {
     int source_dirs_count;
     
     char *comp_dir;
+};
+
+struct mi_compunit {
+    u64 low_pc;
+    u64 high_pc;
+    
+    struct mi_sourceinfo source;
     
-    struct mi_block blocks[4]; // TODO
-    int block_count;
+    int functions_from;
+    int functions_count;
 };
 
 struct mi_debuginfo {
-    struct mi_compunit compilation_units[16]; // TODO
-    int cu_count;
+    struct mi_compunit compilation_units[16];
+    struct mi_function functions[64]; 
+    struct mi_variable variables[64];
     
-    struct mi_function functions[64]; // TODO
+    int cu_count;
     int func_count;
+    int var_count;
 };
 
 struct mi_process {

dwarf.c

@@ -768,30 +768,16 @@ read_debug_info_for_compilation_unit(u8 *file, struct mi_debuginfo *dest,
     u32 depth = 0;
     u64 base_data_offset = data_offset - header_size;
     
-    int found_sr = 0;
-    
-    struct mi_function *func = dest->functions + dest->func_count;
     struct mi_compunit *comp_unit = dest->compilation_units + dest->cu_count;
-    struct mi_block *block = comp_unit->blocks;
-    struct mi_variable *variable = block->variables;
-    
-    enum dwarf_die_tag parent = 0;
+    struct mi_function *func = dest->functions + dest->func_count;
+    struct mi_variable *variable = dest->variables + dest->var_count;
     
-    // TODO: make this not bad 
+    comp_unit->functions_from = dest->func_count;
     
     for (;;) {
         data_offset += decode_leb128(file + data_offset, &code);
         
         if (code == 0) {
-            // NOTE: finalize parent
-            if (parent == DW_TAG_lexical_block) {
-                block->high_pc = block->low_pc + block->high_pc;
-                ++block;
-                ++comp_unit->block_count;
-                variable = block->variables;
-                __builtin_trap();
-            }
-            
             if (depth > 1) {
                 --depth;
                 continue;
@@ -808,7 +794,6 @@ read_debug_info_for_compilation_unit(u8 *file, struct mi_debuginfo *dest,
         
         u32 has_children = file[schema_offset++];
         if (has_children) {
-            parent = tag;
             ++depth;
         }
         
@@ -828,7 +813,7 @@ read_debug_info_for_compilation_unit(u8 *file, struct mi_debuginfo *dest,
                 } else if (attribute == DW_AT_high_pc) {
                     comp_unit->high_pc = value;
                 } else if (attribute == DW_AT_comp_dir) {
-                    comp_unit->comp_dir = (char *) value;
+                    comp_unit->source.comp_dir = (char *) value;
                 }
             } else if (tag == DW_TAG_subprogram) {
                 if (attribute == DW_AT_name) {
@@ -838,12 +823,6 @@ read_debug_info_for_compilation_unit(u8 *file, struct mi_debuginfo *dest,
                 } else if (attribute == DW_AT_high_pc) {
                     func->high_pc = value;
                 }
-            } else if (tag == DW_TAG_lexical_block) {
-                if (attribute == DW_AT_low_pc) {
-                    block->low_pc = value;
-                } else if (attribute == DW_AT_high_pc) {
-                    block->high_pc = value;
-                }
             } else if (tag == DW_TAG_variable) {
                 if (attribute == DW_AT_name) {
                     variable->name = (char *) value;
@@ -853,16 +832,18 @@ read_debug_info_for_compilation_unit(u8 *file, struct mi_debuginfo *dest,
             }
         } while (attribute != 0 || form != 0);
         
-        if (parent == DW_TAG_variable) {
-            ++variable;
-            ++block->var_count;
-        }
-        
-        if (parent == DW_TAG_subprogram) {
+        // NOTE(aolo2): DIE completely processed, finish it up
+        if (tag == DW_TAG_subprogram) {
             func->high_pc = func->low_pc + func->high_pc;
-            func->comp_unit = dest->cu_count;
-            ++func;
+            func->variables_from = dest->var_count;
+            ++comp_unit->functions_count;
             ++dest->func_count;
+            ++func;
+        } else if (tag == DW_TAG_variable) {
+            struct mi_function *parent = func - 1; 
+            ++parent->variables_count;
+            ++dest->var_count;
+            ++variable;
         }
     }
     
@@ -900,14 +881,14 @@ parse_debug_info(u8 *file, struct mi_debuginfo *dest)
 static u64
 read_debug_line_for_compilation_unit(u8 *file, u64 dl_offset, struct mi_compunit *unit)
 {
-    struct mi_sourcepoint *dest = unit->sp_table;
-    int *dest_size = &unit->sp_count;
+    struct mi_sourcepoint *dest = unit->source.sp_table;
+    int *dest_size = &unit->source.sp_count;
     
-    struct mi_sourcefile *dest_files = unit->source_files; 
-    int *dest_files_size = &unit->source_file_count;
+    struct mi_sourcefile *dest_files = unit->source.source_files; 
+    int *dest_files_size = &unit->source.source_file_count;
     
-    char **dest_directories = unit->source_directories;
-    int *dest_directories_size = &unit->source_dirs_count;
+    char **dest_directories = unit->source.source_directories;
+    int *dest_directories_size = &unit->source.source_dirs_count;
     
     struct dwarf_debug_line_header_v3_x32 header = { 0 };
     memcpy(&header, file + dl_offset, 15); /* all fixed-size info */
@@ -1246,9 +1227,9 @@ parse_debug_line(u8 *file, struct mi_debuginfo *debug)
     // count
     for (;;) {
         u64 size = read_debug_line_for_compilation_unit(file, at, unit);
-        unit->sp_table = calloc(1, unit->sp_count * sizeof(struct mi_sourcepoint));
-        unit->source_directories = calloc(1, unit->source_dirs_count * sizeof(char *));
-        unit->source_files = calloc(1, unit->source_file_count * sizeof(struct mi_sourcefile));
+        unit->source.sp_table = calloc(1, unit->source.sp_count * sizeof(struct mi_sourcepoint));
+        unit->source.source_directories = calloc(1, unit->source.source_dirs_count * sizeof(char *));
+        unit->source.source_files = calloc(1, unit->source.source_file_count * sizeof(struct mi_sourcefile));
         read += size;
         at += size;
         ++unit;

main.c

@@ -55,6 +55,8 @@ main(int argc, char *argv[])
             command_next(process);
         } else if (0 == strncmp(command, "line\n", command_length)) {
             command_list(process);
+        } else if (0 == strncmp(command, "bt\n", command_length)) {
+            command_backtrace(process);
         } else if (0 == strncmp(command, "cont\n", command_length)) {
             command_cont(process);
             wait = 1;

res/004-scoped-variables.c

@@ -1,11 +1,38 @@
+void f1();
+void f2();
+void f3();
+
+void
+f3()
+{
+	int a_f3 = 3;
+	f2();
+}
+
+void
+f2()
+{
+	int a_f2 = 2;
+	{
+		int b_f2 = 22;
+		{
+			int c_f2 = 33;
+		}
+	}
+}
+
+void
+f1()
+{
+	int a_f1 = 1;
+	f2();
+}
+
 int
 main(int argc, char **argv)
 {
-	int outer = 1;
-	if (outer > 0) {
-		char *inner = "INNER";
-		int outer = -1;
-		outer += 10;
-	}
+	int a_main = 0;
+	f1();
+	f3();
 	return(0);
 }

util.c

@@ -1,4 +1,3 @@
-
 static struct mi_registers
 get_process_registers(struct mi_process proc)
 {
@@ -114,11 +113,11 @@ pc_to_sourcepoint(struct mi_process proc, u64 pc, int *comp_unit)
     for (int c = 0; c < proc.debug.cu_count; ++c) {
         struct mi_compunit unit = proc.debug.compilation_units[c];
         if (unit.low_pc <= pc && pc < unit.high_pc) {
-            for (int i = 0; i < unit.sp_count; ++i) {
-                struct mi_sourcepoint *point = unit.sp_table + i;
+            for (int i = 0; i < unit.source.sp_count; ++i) {
+                struct mi_sourcepoint *point = unit.source.sp_table + i;
                 if (point->pc > pc) {
                     *comp_unit = c;
-                    return(unit.sp_table + i - 1);
+                    return(unit.source.sp_table + i - 1);
                 }
             }
             break;
@@ -173,19 +172,19 @@ print_sourcepoint(struct mi_process proc, int comp_unit, struct mi_sourcepoint *
     struct mi_compunit unit = proc.debug.compilation_units[comp_unit];
     
     // NOTE: sourcepoint file indices are 1-based
-    if (unit.source_files[sp->file - 1].file.data == 0) {
-        char *file_filename = unit.source_files[sp->file - 1].filename;
-        char *file_dirname = unit.source_files[sp->file - 1].dir;
-        char *comp_dir = unit.comp_dir;
+    if (unit.source.source_files[sp->file - 1].file.data == 0) {
+        char *file_filename = unit.source.source_files[sp->file - 1].filename;
+        char *file_dirname = unit.source.source_files[sp->file - 1].dir;
+        char *comp_dir = unit.source.comp_dir;
         
         char full_path[512] = { 0 };
         snprintf(full_path, 511, "%s/%s/%s", comp_dir, file_dirname, file_filename);
         
         struct mi_buffer file = read_file_mmap(full_path);
-        unit.source_files[sp->file - 1].file = file;
+        unit.source.source_files[sp->file - 1].file = file;
     }
     
-    struct mi_buffer file = unit.source_files[sp->file - 1].file;
+    struct mi_buffer file = unit.source.source_files[sp->file - 1].file;
     
     char *source = (char *) file.data;
     u64 size = file.size;
@@ -280,6 +279,7 @@ lookup_identifier_address(struct mi_process proc, char *ident, int len)
     struct mi_registers regs = get_process_registers(proc);
     u64 pc_local = regs.rip - proc.base_address;
     
+#if 0
     for (int c = 0; c < proc.debug.cu_count; ++c) {
         struct mi_compunit unit = proc.debug.compilation_units[c];
         
@@ -303,6 +303,32 @@ lookup_identifier_address(struct mi_process proc, char *ident, int len)
             
         }
     }
+#endif
     
     return(0);
-}
+}
+
+static struct mi_function *
+get_function_around_pc(struct mi_process proc, u64 pc)
+{
+    struct mi_debuginfo debug = proc.debug;
+    
+    for (int c = 0; c < debug.cu_count; ++c) {
+        struct mi_compunit *unit = debug.compilation_units + c;
+        
+        if (unit->low_pc <= pc && pc < unit->high_pc) {
+            
+            for (int f = 0; f < unit->functions_count; ++f) {
+                struct mi_function *func = debug.functions + unit->functions_from + f;
+                
+                if (func->low_pc <= pc && pc < func->high_pc) {
+                    return(func);
+                }
+            }
+            
+            break;
+        }
+    }
+    
+    return(0);
+}