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authorPedro Alves <palves@redhat.com>2015-03-07 15:14:14 +0000
committerPedro Alves <palves@redhat.com>2015-03-07 15:14:14 +0000
commit492d29ea1c9a8b2c7d5193908119a4e27c045687 (patch)
treeea592a514ec482e6c57020670e9bc447f827e298 /gdb/stack.c
parentece957c859c00fbea7152a2275674d7061dc468a (diff)
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Split TRY_CATCH into TRY + CATCH
This patch splits the TRY_CATCH macro into three, so that we go from this: ~~~ volatile gdb_exception ex; TRY_CATCH (ex, RETURN_MASK_ERROR) { } if (ex.reason < 0) { } ~~~ to this: ~~~ TRY { } CATCH (ex, RETURN_MASK_ERROR) { } END_CATCH ~~~ Thus, we'll be getting rid of the local volatile exception object, and declaring the caught exception in the catch block. This allows reimplementing TRY/CATCH in terms of C++ exceptions when building in C++ mode, while still allowing to build GDB in C mode (using setjmp/longjmp), as a transition step. TBC, after this patch, is it _not_ valid to have code between the TRY and the CATCH blocks, like: TRY { } // some code here. CATCH (ex, RETURN_MASK_ERROR) { } END_CATCH Just like it isn't valid to do that with C++'s native try/catch. By switching to creating the exception object inside the CATCH block scope, we can get rid of all the explicitly allocated volatile exception objects all over the tree, and map the CATCH block more directly to C++'s catch blocks. The majority of the TRY_CATCH -> TRY+CATCH+END_CATCH conversion was done with a script, rerun from scratch at every rebase, no manual editing involved. After the mechanical conversion, a few places needed manual intervention, to fix preexisting cases where we were using the exception object outside of the TRY_CATCH block, and cases where we were using "else" after a 'if (ex.reason) < 0)' [a CATCH after this patch]. The result was folded into this patch so that GDB still builds at each incremental step. END_CATCH is necessary for two reasons: First, because we name the exception object in the CATCH block, which requires creating a scope, which in turn must be closed somewhere. Declaring the exception variable in the initializer field of a for block, like: #define CATCH(EXCEPTION, mask) \ for (struct gdb_exception EXCEPTION; \ exceptions_state_mc_catch (&EXCEPTION, MASK); \ EXCEPTION = exception_none) would avoid needing END_CATCH, but alas, in C mode, we build with C90, which doesn't allow mixed declarations and code. Second, because when TRY/CATCH are wired to real C++ try/catch, as long as we need to handle cleanup chains, even if there's no CATCH block that wants to catch the exception, we need for stop at every frame in the unwind chain and run cleanups, then rethrow. That will be done in END_CATCH. After we require C++, we'll still need TRY/CATCH/END_CATCH until cleanups are completely phased out -- TRY/CATCH in C++ mode will save/restore the current cleanup chain, like in C mode, and END_CATCH catches otherwise uncaugh exceptions, runs cleanups and rethrows, so that C++ cleanups and exceptions can coexist. IMO, this still makes the TRY/CATCH code look a bit more like a newcomer would expect, so IMO worth it even if we weren't considering C++. gdb/ChangeLog. 2015-03-07 Pedro Alves <palves@redhat.com> * common/common-exceptions.c (struct catcher) <exception>: No longer a pointer to volatile exception. Now an exception value. <mask>: Delete field. (exceptions_state_mc_init): Remove all parameters. Adjust. (exceptions_state_mc): No longer pop the catcher here. (exceptions_state_mc_catch): New function. (throw_exception): Adjust. * common/common-exceptions.h (exceptions_state_mc_init): Remove all parameters. (exceptions_state_mc_catch): Declare. (TRY_CATCH): Rename to ... (TRY): ... this. Remove EXCEPTION and MASK parameters. (CATCH, END_CATCH): New. All callers adjusted. gdb/gdbserver/ChangeLog: 2015-03-07 Pedro Alves <palves@redhat.com> Adjust all callers of TRY_CATCH to use TRY/CATCH/END_CATCH instead.
Diffstat (limited to 'gdb/stack.c')
-rw-r--r--gdb/stack.c135
1 files changed, 81 insertions, 54 deletions
diff --git a/gdb/stack.c b/gdb/stack.c
index 5831999..76a2360 100644
--- a/gdb/stack.c
+++ b/gdb/stack.c
@@ -154,19 +154,22 @@ print_stack_frame (struct frame_info *frame, int print_level,
enum print_what print_what,
int set_current_sal)
{
- volatile struct gdb_exception e;
/* For mi, alway print location and address. */
if (ui_out_is_mi_like_p (current_uiout))
print_what = LOC_AND_ADDRESS;
- TRY_CATCH (e, RETURN_MASK_ERROR)
+ TRY
{
print_frame_info (frame, print_level, print_what, 1 /* print_args */,
set_current_sal);
if (set_current_sal)
set_current_sal_from_frame (frame);
}
+ CATCH (e, RETURN_MASK_ERROR)
+ {
+ }
+ END_CATCH
}
/* Print nameless arguments of frame FRAME on STREAM, where START is
@@ -210,9 +213,9 @@ static void
print_frame_arg (const struct frame_arg *arg)
{
struct ui_out *uiout = current_uiout;
- volatile struct gdb_exception except;
struct cleanup *old_chain;
struct ui_file *stb;
+ const char *error_message = NULL;
stb = mem_fileopen ();
old_chain = make_cleanup_ui_file_delete (stb);
@@ -250,12 +253,10 @@ print_frame_arg (const struct frame_arg *arg)
else
{
if (arg->error)
- except.message = arg->error;
+ error_message = arg->error;
else
{
- /* TRY_CATCH has two statements, wrap it in a block. */
-
- TRY_CATCH (except, RETURN_MASK_ERROR)
+ TRY
{
const struct language_defn *language;
struct value_print_options opts;
@@ -284,10 +285,15 @@ print_frame_arg (const struct frame_arg *arg)
common_val_print (arg->val, stb, 2, &opts, language);
}
+ CATCH (except, RETURN_MASK_ERROR)
+ {
+ error_message = except.message;
+ }
+ END_CATCH
}
- if (except.message)
+ if (error_message != NULL)
fprintf_filtered (stb, _("<error reading variable: %s>"),
- except.message);
+ error_message);
}
ui_out_field_stream (uiout, "value", stb);
@@ -306,17 +312,21 @@ void
read_frame_local (struct symbol *sym, struct frame_info *frame,
struct frame_arg *argp)
{
- volatile struct gdb_exception except;
struct value *val = NULL;
- TRY_CATCH (except, RETURN_MASK_ERROR)
+ argp->sym = sym;
+ argp->val = NULL;
+ argp->error = NULL;
+
+ TRY
{
- val = read_var_value (sym, frame);
+ argp->val = read_var_value (sym, frame);
}
-
- argp->error = (val == NULL) ? xstrdup (except.message) : NULL;
- argp->sym = sym;
- argp->val = val;
+ CATCH (except, RETURN_MASK_ERROR)
+ {
+ argp->error = xstrdup (except.message);
+ }
+ END_CATCH
}
/* Read in inferior function parameter SYM at FRAME into ARGP. Caller is
@@ -330,20 +340,20 @@ read_frame_arg (struct symbol *sym, struct frame_info *frame,
struct value *val = NULL, *entryval = NULL;
char *val_error = NULL, *entryval_error = NULL;
int val_equal = 0;
- volatile struct gdb_exception except;
if (print_entry_values != print_entry_values_only
&& print_entry_values != print_entry_values_preferred)
{
- TRY_CATCH (except, RETURN_MASK_ERROR)
+ TRY
{
val = read_var_value (sym, frame);
}
- if (!val)
+ CATCH (except, RETURN_MASK_ERROR)
{
val_error = alloca (strlen (except.message) + 1);
strcpy (val_error, except.message);
}
+ END_CATCH
}
if (SYMBOL_COMPUTED_OPS (sym) != NULL
@@ -352,25 +362,25 @@ read_frame_arg (struct symbol *sym, struct frame_info *frame,
&& (print_entry_values != print_entry_values_if_needed
|| !val || value_optimized_out (val)))
{
- TRY_CATCH (except, RETURN_MASK_ERROR)
+ TRY
{
const struct symbol_computed_ops *ops;
ops = SYMBOL_COMPUTED_OPS (sym);
entryval = ops->read_variable_at_entry (sym, frame);
}
- if (!entryval)
+ CATCH (except, RETURN_MASK_ERROR)
{
- entryval_error = alloca (strlen (except.message) + 1);
- strcpy (entryval_error, except.message);
+ if (except.error != NO_ENTRY_VALUE_ERROR)
+ {
+ entryval_error = (char *) alloca (strlen (except.message) + 1);
+ strcpy (entryval_error, except.message);
+ }
}
+ END_CATCH
- if (except.error == NO_ENTRY_VALUE_ERROR
- || (entryval && value_optimized_out (entryval)))
- {
- entryval = NULL;
- entryval_error = NULL;
- }
+ if (entryval != NULL && value_optimized_out (entryval))
+ entryval = NULL;
if (print_entry_values == print_entry_values_compact
|| print_entry_values == print_entry_values_default)
@@ -396,7 +406,7 @@ read_frame_arg (struct symbol *sym, struct frame_info *frame,
dereferenced DW_AT_GNU_call_site_data_value does not
differ. */
- TRY_CATCH (except, RETURN_MASK_ERROR)
+ TRY
{
struct type *type_deref;
@@ -417,19 +427,23 @@ read_frame_arg (struct symbol *sym, struct frame_info *frame,
TYPE_LENGTH (type_deref)))
val_equal = 1;
}
+ CATCH (except, RETURN_MASK_ERROR)
+ {
+ /* If the dereferenced content could not be
+ fetched do not display anything. */
+ if (except.error == NO_ENTRY_VALUE_ERROR)
+ val_equal = 1;
+ else if (except.message != NULL)
+ {
+ entryval_error = (char *) alloca (strlen (except.message) + 1);
+ strcpy (entryval_error, except.message);
+ }
+ }
+ END_CATCH
/* Value was not a reference; and its content matches. */
if (val == val_deref)
val_equal = 1;
- /* If the dereferenced content could not be fetched do not
- display anything. */
- else if (except.error == NO_ENTRY_VALUE_ERROR)
- val_equal = 1;
- else if (except.message)
- {
- entryval_error = alloca (strlen (except.message) + 1);
- strcpy (entryval_error, except.message);
- }
if (val_equal)
entryval = NULL;
@@ -455,15 +469,18 @@ read_frame_arg (struct symbol *sym, struct frame_info *frame,
{
if (print_entry_values == print_entry_values_preferred)
{
- TRY_CATCH (except, RETURN_MASK_ERROR)
+ gdb_assert (val == NULL);
+
+ TRY
{
val = read_var_value (sym, frame);
}
- if (!val)
+ CATCH (except, RETURN_MASK_ERROR)
{
val_error = alloca (strlen (except.message) + 1);
strcpy (val_error, except.message);
}
+ END_CATCH
}
if (print_entry_values == print_entry_values_only
|| print_entry_values == print_entry_values_both
@@ -748,20 +765,20 @@ static void
do_gdb_disassembly (struct gdbarch *gdbarch,
int how_many, CORE_ADDR low, CORE_ADDR high)
{
- volatile struct gdb_exception exception;
- TRY_CATCH (exception, RETURN_MASK_ERROR)
+ TRY
{
gdb_disassembly (gdbarch, current_uiout, 0,
DISASSEMBLY_RAW_INSN, how_many,
low, high);
}
- if (exception.reason < 0)
+ CATCH (exception, RETURN_MASK_ERROR)
{
/* If an exception was thrown while doing the disassembly, print
the error message, to give the user a clue of what happened. */
exception_print (gdb_stderr, exception);
}
+ END_CATCH
}
/* Print information about frame FRAME. The output is format according
@@ -1188,7 +1205,6 @@ print_frame (struct frame_info *frame, int print_level,
struct gdbarch *gdbarch = get_frame_arch (frame);
int numargs;
struct cleanup *args_list_chain;
- volatile struct gdb_exception e;
if (gdbarch_frame_num_args_p (gdbarch))
{
@@ -1199,10 +1215,15 @@ print_frame (struct frame_info *frame, int print_level,
numargs = -1;
args_list_chain = make_cleanup_ui_out_list_begin_end (uiout, "args");
- TRY_CATCH (e, RETURN_MASK_ERROR)
+ TRY
{
print_frame_args (func, frame, numargs, gdb_stdout);
}
+ CATCH (e, RETURN_MASK_ERROR)
+ {
+ }
+ END_CATCH
+
/* FIXME: ARGS must be a list. If one argument is a string it
will have " that will not be properly escaped. */
/* Invoke ui_out_tuple_end. */
@@ -1410,7 +1431,7 @@ frame_info (char *addr_exp, int from_tty)
int frame_pc_p;
/* Initialize it to avoid "may be used uninitialized" warning. */
CORE_ADDR caller_pc = 0;
- volatile struct gdb_exception ex;
+ int caller_pc_p = 0;
fi = parse_frame_specification_1 (addr_exp, "No stack.", &selected_frame_p);
gdbarch = get_frame_arch (fi);
@@ -1498,11 +1519,12 @@ frame_info (char *addr_exp, int from_tty)
wrap_here (" ");
printf_filtered ("saved %s = ", pc_regname);
- TRY_CATCH (ex, RETURN_MASK_ERROR)
+ TRY
{
caller_pc = frame_unwind_caller_pc (fi);
+ caller_pc_p = 1;
}
- if (ex.reason < 0)
+ CATCH (ex, RETURN_MASK_ERROR)
{
switch (ex.error)
{
@@ -1517,7 +1539,9 @@ frame_info (char *addr_exp, int from_tty)
break;
}
}
- else
+ END_CATCH
+
+ if (caller_pc_p)
fputs_filtered (paddress (gdbarch, caller_pc), gdb_stdout);
printf_filtered ("\n");
@@ -2571,8 +2595,8 @@ get_frame_language (void)
if (frame)
{
- volatile struct gdb_exception ex;
CORE_ADDR pc = 0;
+ int pc_p = 0;
/* We determine the current frame language by looking up its
associated symtab. To retrieve this symtab, we use the frame
@@ -2583,16 +2607,19 @@ get_frame_language (void)
a PC that is guaranteed to be inside the frame's code
block. */
- TRY_CATCH (ex, RETURN_MASK_ERROR)
+ TRY
{
pc = get_frame_address_in_block (frame);
+ pc_p = 1;
}
- if (ex.reason < 0)
+ CATCH (ex, RETURN_MASK_ERROR)
{
if (ex.error != NOT_AVAILABLE_ERROR)
throw_exception (ex);
}
- else
+ END_CATCH
+
+ if (pc_p)
{
struct compunit_symtab *cust = find_pc_compunit_symtab (pc);