From 777bef06cd075ee4031187fe28381d5d5edd4f94 Mon Sep 17 00:00:00 2001 From: Jim Kingdon Date: Mon, 22 Apr 1991 20:08:53 +0000 Subject: [PATCH] Check for NULL selected_frame in various places. --- gdb/breakpoint.c | 14 +++++++++++--- gdb/exec.c | 2 ++ gdb/findvar.c | 15 +++++++++++++-- gdb/infcmd.c | 2 ++ gdb/inflow.c | 18 +++++++++++++++--- gdb/infrun.c | 2 ++ gdb/stack.c | 24 +++++++++++++++++++----- 7 files changed, 64 insertions(+), 13 deletions(-) diff --git a/gdb/breakpoint.c b/gdb/breakpoint.c index e5d3c69c8d..e3f515221c 100644 --- a/gdb/breakpoint.c +++ b/gdb/breakpoint.c @@ -1537,14 +1537,22 @@ get_catch_sals (this_level_only) { extern struct blockvector *blockvector_for_pc (); register struct blockvector *bl; - register struct block *block = get_frame_block (selected_frame); + register struct block *block; int index, have_default = 0; - struct frame_info *fi = get_frame_info (selected_frame); - CORE_ADDR pc = fi->pc; + struct frame_info *fi; + CORE_ADDR pc; struct symtabs_and_lines sals; struct sal_chain *sal_chain = 0; char *blocks_searched; + /* Not sure whether an error message is always the correct response, + but it's better than a core dump. */ + if (selected_frame == NULL) + error ("No selected frame."); + block = get_frame_block (selected_frame); + fi = get_frame_info (selected_frame); + pc = fi->pc; + sals.nelts = 0; sals.sals = NULL; diff --git a/gdb/exec.c b/gdb/exec.c index 730692ae92..32795c640f 100644 --- a/gdb/exec.c +++ b/gdb/exec.c @@ -193,6 +193,8 @@ build_section_table (some_bfd, start, end) count = bfd_count_sections (some_bfd); if (count == 0) abort(); /* return 1? */ + if (*start) + free (*start); *start = (struct section_table *) xmalloc (count * sizeof (**start)); *end = *start; bfd_map_over_sections (some_bfd, add_to_section_table, end); diff --git a/gdb/findvar.c b/gdb/findvar.c index 25ff0baf6d..5ac03bc448 100644 --- a/gdb/findvar.c +++ b/gdb/findvar.c @@ -354,7 +354,8 @@ supply_register (regno, val) /* Given a struct symbol for a variable, and a stack frame id, read the value of the variable and return a (pointer to a) struct value containing the value. - If the variable cannot be found, return a zero pointer. */ + If the variable cannot be found, return a zero pointer. + If FRAME is NULL, use the selected_frame. */ value read_var_value (var, frame) @@ -411,6 +412,8 @@ read_var_value (var, frame) case LOC_ARG: fi = get_frame_info (frame); + if (fi == NULL) + return 0; addr = FRAME_ARGS_ADDRESS (fi); if (!addr) { return 0; @@ -420,6 +423,8 @@ read_var_value (var, frame) case LOC_REF_ARG: fi = get_frame_info (frame); + if (fi == NULL) + return 0; addr = FRAME_ARGS_ADDRESS (fi); if (!addr) { return 0; @@ -431,6 +436,8 @@ read_var_value (var, frame) case LOC_LOCAL: case LOC_LOCAL_ARG: fi = get_frame_info (frame); + if (fi == NULL) + return 0; addr = SYMBOL_VALUE (var) + FRAME_LOCALS_ADDRESS (fi); break; @@ -445,8 +452,12 @@ read_var_value (var, frame) case LOC_REGISTER: case LOC_REGPARM: { - struct block *b = get_frame_block (frame); + struct block *b; + if (frame == NULL) + return 0; + b = get_frame_block (frame); + v = value_from_register (type, SYMBOL_VALUE (var), frame); if (REG_STRUCT_HAS_ADDR(b->gcc_compile_flag) diff --git a/gdb/infcmd.c b/gdb/infcmd.c index 25883a0a93..2ebfb0b1c3 100644 --- a/gdb/infcmd.c +++ b/gdb/infcmd.c @@ -529,6 +529,8 @@ finish_command (arg, from_tty) error ("The \"finish\" command does not take any arguments."); if (!target_has_execution) error ("The program is not running."); + if (selected_frame == NULL) + error ("No selected frame."); frame = get_prev_frame (selected_frame); if (frame == 0) diff --git a/gdb/inflow.c b/gdb/inflow.c index 6e6905fd50..3d0c68aea5 100644 --- a/gdb/inflow.c +++ b/gdb/inflow.c @@ -364,6 +364,16 @@ kill_command (arg, from_tty) if (!query ("Kill the inferior process? ")) error ("Not confirmed."); target_kill (arg, from_tty); + + /* Killing off the inferior can leave us with a core file. If so, + print the state we are left in. */ + if (target_has_stack) { + printf_filtered ("In %s,\n", current_target->to_longname); + if (selected_frame == NULL) + fputs_filtered ("No selected stack frame.\n", stdout); + else + print_sel_frame (0); + } } /* The inferior process has died. Long live the inferior! */ @@ -381,13 +391,15 @@ generic_mourn_inferior () CLEAR_DEFERRED_STORES; #endif - select_frame ((FRAME) 0, -1); reopen_exec_file (); - if (target_has_stack) + if (target_has_stack) { set_current_frame ( create_new_frame (read_register (FP_REGNUM), read_pc ())); - else + select_frame (get_current_frame (), 0); + } else { set_current_frame (0); + select_frame ((FRAME) 0, -1); + } /* It is confusing to the user for ignore counts to stick around from previous runs of the inferior. So clear them. */ breakpoint_clear_ignore_counts (); diff --git a/gdb/infrun.c b/gdb/infrun.c index ac15f37d10..0c3a3e80e9 100644 --- a/gdb/infrun.c +++ b/gdb/infrun.c @@ -1605,6 +1605,8 @@ restore_inferior_status (inf_status) fid = find_relative_frame (get_current_frame (), &level); + /* If inf_status->selected_frame_address is NULL, there was no + previously selected frame. */ if (fid == 0 || FRAME_FP (fid) != inf_status->selected_frame_address || level != 0) diff --git a/gdb/stack.c b/gdb/stack.c index 09920130b7..e8041fb842 100644 --- a/gdb/stack.c +++ b/gdb/stack.c @@ -221,6 +221,8 @@ extern FRAME setup_arbitrary_frame (); /* * Read a frame specification in whatever the appropriate format is. + * Call error() if the specification is in any way invalid (i.e. + * this function never returns NULL). */ static FRAME parse_frame_specification (frame_exp) @@ -262,6 +264,8 @@ parse_frame_specification (frame_exp) switch (numargs) { case 0: + if (selected_frame == NULL) + error ("No selected frame."); return selected_frame; /* NOTREACHED */ case 1: @@ -477,6 +481,9 @@ backtrace_command (count_exp, from_tty) register FRAME trailing; register int trailing_level; + if (!target_has_stack) + error ("No stack."); + /* The following code must do two things. First, it must set the variable TRAILING to the frame from which we should start printing. Second, it must set the variable count to the number @@ -846,14 +853,15 @@ select_frame (frame, level) find_pc_symtab (get_frame_info (frame)->pc); } -/* Store the selected frame and its level into *FRAMEP and *LEVELP. */ +/* Store the selected frame and its level into *FRAMEP and *LEVELP. + If there is no selected frame, *FRAMEP is set to NULL. */ void record_selected_frame (frameaddrp, levelp) FRAME_ADDR *frameaddrp; int *levelp; { - *frameaddrp = FRAME_FP (selected_frame); + *frameaddrp = selected_frame ? FRAME_FP (selected_frame) : NULL; *levelp = selected_frame_level; } @@ -1028,11 +1036,17 @@ return_command (retval_exp, from_tty) char *retval_exp; int from_tty; { - struct symbol *thisfun = get_frame_function (selected_frame); - FRAME_ADDR selected_frame_addr = FRAME_FP (selected_frame); - CORE_ADDR selected_frame_pc = (get_frame_info (selected_frame))->pc; + struct symbol *thisfun; + FRAME_ADDR selected_frame_addr; + CORE_ADDR selected_frame_pc; FRAME frame; + if (selected_frame == NULL) + error ("No selected frame."); + thisfun = get_frame_function (selected_frame); + selected_frame_addr = FRAME_FP (selected_frame); + selected_frame_pc = (get_frame_info (selected_frame))->pc; + /* If interactive, require confirmation. */ if (from_tty) -- 2.34.1