[Bug symtab/26046] New: Missing breakpoint location without -readnow

[Bug symtab/26046] New: Missing breakpoint location without -readnow

[vries at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=26046

            Bug ID: 26046
           Summary: Missing breakpoint location without -readnow
           Product: gdb
           Version: HEAD
            Status: NEW
          Severity: normal
          Priority: P2
         Component: symtab
          Assignee: unassigned at sourceware dot org
          Reporter: vries at gcc dot gnu.org
  Target Milestone: ---

Consider the following test-case (based on the test-case from PR15646):
...
$ cat foo.h
namespace N1
{
  class C1
  {
   public:
    static void __attribute__((always_inline)) baz () { volatile unsigned i;
i++; }
  };
}
$ cat foo.cc
#include "foo.h"

namespace N1
{
  void foo () { C1::baz (); }
}

extern void N1_bar (void);

int
main ()
{
  N1::foo ();
  N1_bar ();
  return 0;
}
$ cat foo-2.cc
#include "foo.h"

namespace N1
{
  void bar () { C1::baz (); }
}

void
N1_bar (void)
{
  N1::bar ();
}
...

Compiled like this:
...
$ g++ foo.cc foo-2.cc -g
...


With -readnow, we set two breakpoint locations for N1::C1::baz:
...
$ gdb -readnow a.out -ex "b N1::C1::baz" -ex "info break"
Reading symbols from a.out...
Expanding full symbols from a.out...
Breakpoint 1 at 0x4004cb: N1::C1::baz. (2 locations)
Num     Type           Disp Enb Address            What
1       breakpoint     keep y   <MULTIPLE>         
1.1                         y   0x00000000004004cb in N1::C1::baz() at foo.h:6
1.2                         y   0x00000000004004f0 in N1::C1::baz() at foo.h:6
...

However, without -readnow, using partial symbols, we only get one breakpoint
location:
...
$ gdb a.out -ex "b N1::C1::baz" -ex "info break"
Reading symbols from a.out...
Breakpoint 1 at 0x4004f0: file foo.h, line 6.
Num     Type           Disp Enb Address            What
1       breakpoint     keep y   0x00000000004004f0 in N1::C1::baz() at foo.h:6
...

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[Bug symtab/26046] Missing breakpoint location without -readnow

[vries at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=26046

Tom de Vries <vries at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |tromey at sourceware dot org

--- Comment #1 from Tom de Vries <vries at gcc dot gnu.org> ---
Tentative patch:
...
diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c
index ec3844188e..bbd57325f5 100644
--- a/gdb/dwarf2/read.c
+++ b/gdb/dwarf2/read.c
@@ -8054,6 +8054,8 @@ scan_partial_symbols (struct partial_die_info *first_die,
CORE_ADDR *lowpc,
            case DW_TAG_subprogram:
            case DW_TAG_inlined_subroutine:
              add_partial_subprogram (pdi, lowpc, highpc, set_addrmap, cu);
+             scan_partial_symbols (pdi->die_child, lowpc, highpc,
+                                   set_addrmap, cu);
              break;
            case DW_TAG_constant:
            case DW_TAG_variable:
@@ -18125,7 +18127,8 @@ load_partial_dies (const struct die_reader_specs
*reader,
       if (!load_all
          && cu->language == language_cplus
          && parent_die != NULL
-         && parent_die->tag == DW_TAG_subprogram)
+         && parent_die->tag == DW_TAG_subprogram
+         && abbrev->tag != DW_TAG_inlined_subroutine)
        {
          info_ptr = skip_one_die (reader, info_ptr + bytes_read, abbrev);
          continue;
@@ -18300,9 +18303,7 @@ load_partial_dies (const struct die_reader_specs
*reader,
              || last_die->tag == DW_TAG_module
              || last_die->tag == DW_TAG_enumeration_type
              || (cu->language == language_cplus
-                 && last_die->tag == DW_TAG_subprogram
-                 && (last_die->name == NULL
-                     || strchr (last_die->name, '<') == NULL))
+                 && last_die->tag == DW_TAG_subprogram)
              || (cu->language != language_c
                  && (last_die->tag == DW_TAG_class_type
                      || last_die->tag == DW_TAG_interface_type
...

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[Bug symtab/26046] Missing breakpoint location without -readnow

[vries at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=26046

--- Comment #2 from Tom de Vries <vries at gcc dot gnu.org> ---
submitted patch:
https://sourceware.org/pipermail/gdb-patches/2020-May/169055.html

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[Bug symtab/26046] Missing breakpoint location without -readnow

[cvs-commit at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=26046

--- Comment #3 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Tom de Vries <vries@sourceware.org>:

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=f9b5d5ea18a3878ca48c1b747e35d456133858bc

commit f9b5d5ea18a3878ca48c1b747e35d456133858bc
Author: Tom de Vries <tdevries@suse.de>
Date:   Wed Jun 3 23:50:16 2020 +0200

    [gdb/symtab] Fix missing breakpoint location for inlined function

    Consider the test-case contained in this patch.

    With -readnow, we have two breakpoint locations:
    ...
    $ gdb -readnow -batch breakpoint-locs -ex "b N1::C1::baz" -ex "info break"
    Breakpoint 1 at 0x4004cb: N1::C1::baz. (2 locations)
    Num     Type           Disp Enb Address            What
    1       breakpoint     keep y   <MULTIPLE>
    1.1                         y   0x00000000004004cb in N1::C1::baz() \
                                                         at breakpoint-locs.h:6
    1.2                         y   0x00000000004004f0 in N1::C1::baz() \
                                                         at breakpoint-locs.h:6
    ...

    But without -readnow, we have instead only one breakpoint location:
    ...
    $ gdb -batch breakpoint-locs -ex "b N1::C1::baz" -ex "info break"
    Breakpoint 1 at 0x4004f0: file breakpoint-locs.h, line 6.
    Num     Type           Disp Enb Address            What
    1       breakpoint     keep y   0x00000000004004f0 in N1::C1::baz() \
                                                         at breakpoint-locs.h:6
    ...

    The relevant dwarf is this bit:
    ...
     <0><d2>: Abbrev Number: 1 (DW_TAG_compile_unit)
        <d8>   DW_AT_name        : breakpoint-locs.cc
     <1><f4>: Abbrev Number: 2 (DW_TAG_namespace)
        <f5>   DW_AT_name        : N1
     <2><fe>: Abbrev Number: 3 (DW_TAG_class_type)
        <ff>   DW_AT_name        : C1
     <3><109>: Abbrev Number: 4 (DW_TAG_subprogram)
        <10a>   DW_AT_name        : baz
        <110>   DW_AT_linkage_name: _ZN2N12C13bazEv
     <2><116>: Abbrev Number: 5 (DW_TAG_subprogram)
        <117>   DW_AT_name        : foo
        <11d>   DW_AT_linkage_name: _ZN2N13fooEv
     <1><146>: Abbrev Number: 8 (DW_TAG_subprogram)
        <147>   DW_AT_specification: <0x116>
        <14b>   DW_AT_low_pc      : 0x4004c7
        <153>   DW_AT_high_pc     : 0x10
     <2><161>: Abbrev Number: 9 (DW_TAG_inlined_subroutine)
        <162>   DW_AT_abstract_origin: <0x194>
        <166>   DW_AT_low_pc      : 0x4004cb
        <16e>   DW_AT_high_pc     : 0x9
     <1><194>: Abbrev Number: 12 (DW_TAG_subprogram)
        <195>   DW_AT_specification: <0x109>
        <199>   DW_AT_inline      : 3       (declared as inline and inlined)
    ...

    The missing breakpoint location is specified by DIE 0x161, which is ignored
by
    the partial DIE reader because it's a child of a DW_TAG_subprogram DIE (at
    0x146, for foo).

    Fix this by not ignoring the DIE during partial DIE reading.

    Tested on x86_64-linux.

    gdb/ChangeLog:

    2020-06-03  Tom de Vries  <tdevries@suse.de>

            PR symtab/26046
            * dwarf2/read.c (scan_partial_symbols): Recurse into
DW_TAG_subprogram
            children for C++.
            (load_partial_dies): Don't skip DW_TAG_inlined_subroutine child of
            DW_TAG_subprogram.

    gdb/testsuite/ChangeLog:

    2020-06-03  Tom de Vries  <tdevries@suse.de>

            PR symtab/26046
            * gdb.cp/breakpoint-locs-2.cc: New test.
            * gdb.cp/breakpoint-locs.cc: New test.
            * gdb.cp/breakpoint-locs.exp: New file.
            * gdb.cp/breakpoint-locs.h: New test.

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[Bug symtab/26046] Missing breakpoint location without -readnow

[vries at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=26046

Tom de Vries <vries at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
             Status|NEW                         |RESOLVED

--- Comment #4 from Tom de Vries <vries at gcc dot gnu.org> ---
patch with test-case committed, marking resolved-fixed.

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