On Sat, Sep 30, 2017 at 11:08 AM, Alexandre Oliva <aol...@redhat.com> wrote:
> Introduce a command line option to enable statement frontiers, enabled
> by default in optimized builds with DWARF2+ debug information.
>
> This patch depends on an earlier patch that completed the
> infrastructure for debug markers, and on another patch that turns -g
> into a negatable option prefix.
Ok.
Richard.
> gcc/ChangeLog
>
> * common.opt (gstatement-frontiers): New, setting
> debug_nonbind_markers_p.
> * rtl.h (MAY_HAVE_DEBUG_MARKER_INSNS): Activate.
> * toplev.c (process_options): Autodetect value for debug statement
> frontiers option.
> * tree.h (MAY_HAVE_DEBUG_MARKER_STMTS): Activate.
> * doc/invoke.texi (gstatement-frontiers, gno-statement-frontiers):
> New.
> ---
> gcc/common.opt | 4 ++++
> gcc/doc/invoke.texi | 12 ++++++++++++
> gcc/rtl.h | 2 +-
> gcc/toplev.c | 4 ++++
> gcc/tree.h | 2 +-
> 5 files changed, 22 insertions(+), 2 deletions(-)
>
> diff --git a/gcc/common.opt b/gcc/common.opt
> index dfde6ad..a12c11c 100644
> --- a/gcc/common.opt
> +++ b/gcc/common.opt
> @@ -2889,6 +2889,10 @@ gstabs+
> Common Driver JoinedOrMissing Negative(gvms)
> Generate debug information in extended STABS format.
>
> +gstatement-frontiers
> +Common Driver Var(debug_nonbind_markers_p) Init(2)
> +Emit progressive recommended breakpoint locations.
> +
> gstrict-dwarf
> Common Driver Report Var(dwarf_strict) Init(0)
> Don't emit DWARF additions beyond selected version.
> diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
> index 108d730..85e41e4 100644
> --- a/gcc/doc/invoke.texi
> +++ b/gcc/doc/invoke.texi
> @@ -346,6 +346,7 @@ Objective-C and Objective-C++ Dialects}.
> -ggdb -grecord-gcc-switches -gno-record-gcc-switches @gol
> -gstabs -gstabs+ -gstrict-dwarf -gno-strict-dwarf @gol
> -gcolumn-info -gno-column-info @gol
> +-gstatement-frontiers -gno-statement-frontiers @gol
> -gvms -gxcoff -gxcoff+ -gz@r{[}=@var{type}@r{]} @gol
> -fdebug-prefix-map=@var{old}=@var{new} -fdebug-types-section @gol
> -fno-eliminate-unused-debug-types @gol
> @@ -7040,6 +7041,17 @@ Emit location column information into DWARF debugging
> information, rather
> than just file and line.
> This option is disabled by default.
>
> +@item -gstatement-frontiers
> +@item -gno-statement-frontiers
> +@opindex gstatement-frontiers
> +@opindex gno-statement-frontiers
> +This option causes GCC to create markers in the internal representation
> +at the beginning of statements, and to keep them roughly in place
> +throughout compilation, using them to guide the output of @code{is_stmt}
> +markers in the line number table. This is enabled by default when
> +compiling with optimization (@option{-Os}, @option{-O}, @option{-O2},
> +@dots{}), and outputting DWARF 2 debug information at the normal level.
> +
> @item -gz@r{[}=@var{type}@r{]}
> @opindex gz
> Produce compressed debug sections in DWARF format, if that is supported.
> diff --git a/gcc/rtl.h b/gcc/rtl.h
> index c79a277..a0c27fc 100644
> --- a/gcc/rtl.h
> +++ b/gcc/rtl.h
> @@ -816,7 +816,7 @@ struct GTY(()) rtvec_def {
> #define NONDEBUG_INSN_P(X) (INSN_P (X) && !DEBUG_INSN_P (X))
>
> /* Nonzero if DEBUG_MARKER_INSN_P may possibly hold. */
> -#define MAY_HAVE_DEBUG_MARKER_INSNS 0 /* debug_nonbind_markers_p */
> +#define MAY_HAVE_DEBUG_MARKER_INSNS debug_nonbind_markers_p
> /* Nonzero if DEBUG_BIND_INSN_P may possibly hold. */
> #define MAY_HAVE_DEBUG_BIND_INSNS flag_var_tracking_assignments
> /* Nonzero if DEBUG_INSN_P may possibly hold. */
> diff --git a/gcc/toplev.c b/gcc/toplev.c
> index bee79d3..0ef46da 100644
> --- a/gcc/toplev.c
> +++ b/gcc/toplev.c
> @@ -1514,6 +1514,10 @@ process_options (void)
> warning_at (UNKNOWN_LOCATION, 0,
> "var-tracking-assignments changes selective scheduling");
>
> + if (debug_nonbind_markers_p == AUTODETECT_VALUE)
> + debug_nonbind_markers_p = optimize && debug_info_level >=
> DINFO_LEVEL_NORMAL
> + && (write_symbols == DWARF2_DEBUG || write_symbols ==
> VMS_AND_DWARF2_DEBUG);
> +
> if (flag_tree_cselim == AUTODETECT_VALUE)
> {
> if (HAVE_conditional_move)
> diff --git a/gcc/tree.h b/gcc/tree.h
> index 62a85ea..8c3bda1 100644
> --- a/gcc/tree.h
> +++ b/gcc/tree.h
> @@ -1127,7 +1127,7 @@ extern void omp_clause_range_check_failed (const_tree,
> const char *, int,
> ((int)TREE_INT_CST_LOW (VL_EXP_CHECK (NODE)->exp.operands[0]))
>
> /* Nonzero if gimple_debug_nonbind_marker_p() may possibly hold. */
> -#define MAY_HAVE_DEBUG_MARKER_STMTS 0 /* debug_nonbind_markers_p */
> +#define MAY_HAVE_DEBUG_MARKER_STMTS debug_nonbind_markers_p
> /* Nonzero if gimple_debug_bind_p() (and thus
> gimple_debug_source_bind_p()) may possibly hold. */
> #define MAY_HAVE_DEBUG_BIND_STMTS flag_var_tracking_assignments
> --
> 2.9.5
>
