Re: [SFN+LVU+IEPM v4 6/9] [SFN] Introduce -gstatement-frontiers option, enable debug markers

[Christophe Lyon <christophe dot lyon at linaro dot org>]

Hi,


On 12 December 2017 at 03:42, Alexandre Oliva <aoliva@redhat.com> wrote:
> On Dec  7, 2017, Jeff Law <law@redhat.com> wrote:
>
>> On 11/09/2017 07:34 PM, Alexandre Oliva wrote:
>>> Introduce a command line option to enable statement frontiers, enabled
>>> by default in optimized builds with DWARF2+ debug information.
>> OK once all prereqs are ack'd.
>
> Thanks, here's what's installed, FTR:
>
> From aa2fd8850c18861c8e3811b9174b0b1667111783 Mon Sep 17 00:00:00 2001
> From: aoliva <aoliva@138bc75d-0d04-0410-961f-82ee72b054a4>
> Date: Tue, 12 Dec 2017 02:16:31 +0000
> Subject: [PATCH 6/7] [SFN] Introduce -gstatement-frontiers option, enable
>  debug markers
>
> 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.
>
> for  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.
>
> git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@255569 138bc75d-0d04-0410-961f-82ee72b054a4


Since this was checked in, I've noticed GCC/libatomic build failures
on ARM targets when configuring
--with-mode thumb (--with-mode arm is OK).

I'm seeing this:
/tmp/923972_2.tmpdir/aci-gcc-fsf/builds/gcc-fsf-gccsrc-thumb/obj-arm-none-linux-gnueabi/gcc3/./gcc/xgcc
-B/tmp/923972_2.tmpdir/aci-gcc-fsf/builds/gcc-fsf-gccsrc-thumb/obj-arm-none-
linux-gnueabi/gcc3/./gcc/
-B/tmp/923972_2.tmpdir/aci-gcc-fsf/builds/gcc-fsf-gccsrc-thumb/tools/arm-none-linux-gnueabi/bin/
-B/tmp/923972_2.tmpdir/aci-gcc-fsf/builds/gcc-fsf-gccsrc-thumb/tools/arm-non
e-linux-gnueabi/lib/ -isystem
/tmp/923972_2.tmpdir/aci-gcc-fsf/builds/gcc-fsf-gccsrc-thumb/tools/arm-none-linux-gnueabi/include
-isystem /tmp/923972_2.tmpdir/aci-gcc-fsf/builds/gcc-fsf-gccsrc-thumb/t
ools/arm-none-linux-gnueabi/sys-include -DHAVE_CONFIG_H
-I/tmp/923972_2.tmpdir/aci-gcc-fsf/sources/gcc-fsf/gccsrc/libatomic/config/arm
-I/tmp/923972_2.tmpdir/aci-gcc-fsf/sources/gcc-fsf/gccsrc/libato
mic/config/linux/arm
-I/tmp/923972_2.tmpdir/aci-gcc-fsf/sources/gcc-fsf/gccsrc/libatomic/config/posix
-I/tmp/923972_2.tmpdir/aci-gcc-fsf/sources/gcc-fsf/gccsrc/libatomic
-I. -Wall -Werror -pthread -g
 -O2 -MT gload.lo -MD -MP -MF .deps/gload.Tpo -c
/tmp/923972_2.tmpdir/aci-gcc-fsf/sources/gcc-fsf/gccsrc/libatomic/gload.c
 -fPIC -DPIC -o .libs/gload.o
/tmp/923972_2.tmpdir/ccxBYdCX.s: Assembler messages:
/tmp/923972_2.tmpdir/ccxBYdCX.s: Error: unaligned opcodes detected in
executable segment
make[4]: *** [gload.lo] Error 1
make[4]: Leaving directory
`/tmp/923972_2.tmpdir/aci-gcc-fsf/builds/gcc-fsf-gccsrc-thumb/obj-arm-none-linux-gnueabi/gcc3/arm-none-linux-gnueabi/libatomic'

Christophe

> ---
>  gcc/ChangeLog       |  8 ++++++++
>  gcc/common.opt      |  4 ++++
>  gcc/doc/invoke.texi | 12 ++++++++++++
>  gcc/rtl.h           |  2 +-
>  gcc/toplev.c        |  4 ++++
>  gcc/tree.h          |  2 +-
>  6 files changed, 30 insertions(+), 2 deletions(-)
>
> diff --git a/gcc/ChangeLog b/gcc/ChangeLog
> index 01bd2b9f49ad..a53e7b8173f5 100644
> --- a/gcc/ChangeLog
> +++ b/gcc/ChangeLog
> @@ -1,5 +1,13 @@
>  2017-12-12  Alexandre Oliva <aoliva@redhat.com>
>
> +       * 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.
> +
>         * cfgexpand.c (expand_gimple_basic_block): Handle begin stmt
>         markers.  Integrate source bind into debug stmt expand loop.
>         (pass_expand::execute): Check debug marker limit.  Avoid deep
> diff --git a/gcc/common.opt b/gcc/common.opt
> index 57b3cd7304ab..d80ae5b7f39b 100644
> --- a/gcc/common.opt
> +++ b/gcc/common.opt
> @@ -2936,6 +2936,10 @@ 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 189b3e438fff..6402a5ae1734 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
> @@ -7146,6 +7147,17 @@ Emit location column information into DWARF debugging information, rather
>  than just file and line.
>  This option is enabled 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 4de167d982cf..3ef687e5a371 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 2f154960a170..b6e038d2f89d 100644
> --- a/gcc/toplev.c
> +++ b/gcc/toplev.c
> @@ -1536,6 +1536,10 @@ 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 892a8ba7f707..83af3bcaf55f 100644
> --- a/gcc/tree.h
> +++ b/gcc/tree.h
> @@ -1124,7 +1124,7 @@ 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
> --
> 2.13.6
>
>
>
> --
> Alexandre Oliva, freedom fighter    http://FSFLA.org/~lxoliva/
> You must be the change you wish to see in the world. -- Gandhi
> Be Free! -- http://FSFLA.org/   FSF Latin America board member
> Free Software Evangelist|Red Hat Brasil GNU Toolchain Engineer