On Tue, May 16, 2017 at 7:16 PM, Andi Kleen <a...@firstfloor.org> wrote:
> From: Andi Kleen <a...@linux.intel.com>
>
> When running creduce on an ICE substantial amounts of the total
> CPU time go to backtrace_qsort() (sorting dwarf of the compiler) for
> printing the backtrace of the ICE. When running a reduction we don't need the
> backtrace. So add a -dB option to turn it off, and make reduction
> a bit faster.
Now let me comment on the patch itself because I think it can be
simplified a lot.
>
> Passes bootstrap and testing on x86_64-linux
>
> gcc/:
>
> 2017-05-16 Andi Kleen <a...@linux.intel.com>
>
> * diagnostic.c (diagnostic_initialize): Set disable_backtrace to
> false.
> (diagnostic_action_after_output): Check disable_backtrace.
> * diagnostic.h (struct diagnostic_context): Add
> disable_backtrace.
> * doc/invoke.texi (-dB): Document.
> * opts.c (decode_d_option): Handle -dB.
> ---
> gcc/diagnostic.c | 16 ++++++++++------
> gcc/diagnostic.h | 7 +++++++
> gcc/doc/invoke.texi | 6 ++++++
> gcc/opts.c | 3 +++
> 4 files changed, 26 insertions(+), 6 deletions(-)
>
> diff --git a/gcc/diagnostic.c b/gcc/diagnostic.c
> index 158519606f8..bbac3f384d4 100644
> --- a/gcc/diagnostic.c
> +++ b/gcc/diagnostic.c
> @@ -156,6 +156,7 @@ diagnostic_initialize (diagnostic_context *context, int
> n_opts)
> context->caret_chars[i] = '^';
> context->show_option_requested = false;
> context->abort_on_error = false;
> + context->disable_backtrace = false;
> context->show_column = false;
> context->pedantic_errors = false;
> context->permissive = false;
> @@ -500,13 +501,16 @@ diagnostic_action_after_output (diagnostic_context
> *context,
> case DK_ICE:
> case DK_ICE_NOBT:
> {
> - struct backtrace_state *state = NULL;
> - if (diag_kind == DK_ICE)
> - state = backtrace_create_state (NULL, 0, bt_err_callback, NULL);
> int count = 0;
> - if (state != NULL)
> - backtrace_full (state, 2, bt_callback, bt_err_callback,
> - (void *) &count);
> + if (!context->disable_backtrace)
> + {
> + struct backtrace_state *state = NULL;
> + if (diag_kind == DK_ICE)
Why not put && !context->disable_backtrace in this if statement
instead of wrapping the whole thing in an another if statement?
That is:
struct backtrace_state *state = NULL;
if (diag_kind == DK_ICE && !context->disable_backtrace)
state = backtrace_create_state (NULL, 0, bt_err_callback, NULL);
int count = 0;
if (state != NULL)
backtrace_full (state, 2, bt_callback, bt_err_callback,
(void *) &count);
Changing only one line and instead of many.
Thanks,
Andrew Pinski
> + state = backtrace_create_state (NULL, 0, bt_err_callback, NULL);
> + if (state != NULL)
> + backtrace_full (state, 2, bt_callback, bt_err_callback,
> + (void *) &count);
> + }
>
> if (context->abort_on_error)
> real_abort ();
> diff --git a/gcc/diagnostic.h b/gcc/diagnostic.h
> index dbd1703e0ef..440b547c6da 100644
> --- a/gcc/diagnostic.h
> +++ b/gcc/diagnostic.h
> @@ -120,6 +120,9 @@ struct diagnostic_context
> /* True if we should raise a SIGABRT on errors. */
> bool abort_on_error;
>
> + /* If true don't print backtraces for internal errors. */
> + bool disable_backtrace;
> +
> /* True if we should show the column number on diagnostics. */
> bool show_column;
>
> @@ -245,6 +248,10 @@ diagnostic_inhibit_notes (diagnostic_context * context)
> #define diagnostic_abort_on_error(DC) \
> (DC)->abort_on_error = true
>
> +/* Don't print backtraces for internal errors. */
> +#define diagnostic_disable_backtrace(DC) \
> + (DC)->disable_backtrace = true;
> +
> /* This diagnostic_context is used by front-ends that directly output
> diagnostic messages without going through `error', `warning',
> and similar functions. */
> diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
> index 715830a1a43..677e78c7078 100644
> --- a/gcc/doc/invoke.texi
> +++ b/gcc/doc/invoke.texi
> @@ -12889,6 +12889,12 @@ Produce all the dumps listed above.
> @opindex dA
> Annotate the assembler output with miscellaneous debugging information.
>
> +@item -dB
> +@opindex dB
> +Do not print backtraces on compiler crashes. This speeds up reducing
> +test cases for compiler crashes, because printing backtraces is relatively
> +slow.
> +
> @item -dD
> @opindex dD
> Dump all macro definitions, at the end of preprocessing, in addition to
> diff --git a/gcc/opts.c b/gcc/opts.c
> index ffedb10f18f..0c1da107714 100644
> --- a/gcc/opts.c
> +++ b/gcc/opts.c
> @@ -2593,6 +2593,9 @@ decode_d_option (const char *arg, struct gcc_options
> *opts,
> case 'a':
> opts->x_flag_dump_all_passed = true;
> break;
> + case 'B':
> + diagnostic_disable_backtrace (dc);
> + break;
>
> default:
> warning_at (loc, 0, "unrecognized gcc debugging option: %c", c);
> --
> 2.12.2
>
