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[gdb] Fix missing symtab includes

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[ The test-case requires commit c1a66c0629 "[gdb] Expand symbolless symtabs
using maint expand-symtabs". ]

Consider the debug info for the test-case included in this patch.  It consists
of a PU:
...
 <0><d2>: Abbrev Number: 2 (DW_TAG_partial_unit)
 <1><d3>: Abbrev Number: 0
...
imported by a CU:
...
 <0><df>: Abbrev Number: 2 (DW_TAG_compile_unit)
    <e0>   DW_AT_language    : 2        (non-ANSI C)
    <e1>   DW_AT_stmt_list   : 0xe9
 <1><e5>: Abbrev Number: 3 (DW_TAG_imported_unit)
    <e6>   DW_AT_import      : <0xd2>   [Abbrev Number: 2]
 <1><ea>: Abbrev Number: 0
...
and the CU has a dw2-symtab-includes.h file in the .debug_line file name
table:
...
 The Directory Table (offset 0x101):
  1     /data/gdb_versions/devel/src/gdb/testsuite/gdb.dwarf2

 The File Name Table (offset 0x138):
  Entry Dir     Time    Size    Name
  1     1       0       0       dw2-symtab-includes.h
...

After expanding all symtabs, we can see the CU listed in the user field of the
PU, and vice-versa the PU listed in the includes of the CU:
...
$ gdb.sh -batch \
  -iex "set language c" \
  outputs/gdb.dwarf2/dw2-symtab-includes/dw2-symtab-includes \
  -ex "maint expand-symtabs" \
  -ex "maint info symtabs"
  ...
  { ((struct compunit_symtab *) 0x394dd60)
    debugformat DWARF 2
    producer (null)
    dirname (null)
    blockvector ((struct blockvector *) 0x394dea0)
    user ((struct compunit_symtab *) 0x394dba0)
  }
  { ((struct compunit_symtab *) 0x394dba0)
    debugformat DWARF 2
    producer (null)
    dirname (null)
    blockvector ((struct blockvector *) 0x394dd10)
    user ((struct compunit_symtab *) (null))
    ( includes
      ((struct compunit_symtab *) 0x394dd60)
    )
  }
...

But if we instead only expand the symtab for the dw2-symtab-includes.h file,
the includes and user links are gone:
...
$ gdb -batch \
  -iex "set language c" \
  outputs/gdb.dwarf2/dw2-symtab-includes/dw2-symtab-includes \
  -ex "maint expand-symtabs dw2-symtab-includes.h" \
  -ex "maint info symtabs"
  ...
  { ((struct compunit_symtab *) 0x2728210)
    debugformat DWARF 2
    producer (null)
    dirname (null)
    blockvector ((struct blockvector *) 0x2728350)
    user ((struct compunit_symtab *) (null))
  }
  { ((struct compunit_symtab *) 0x2728050)
    debugformat DWARF 2
    producer (null)
    dirname (null)
    blockvector ((struct blockvector *) 0x27281c0)
    user ((struct compunit_symtab *) (null))
  }
...

The includes are calculated by process_cu_includes in gdb/dwarf2/read.c.

In the case of expanding all symtabs:
- the CU partial symtab is expanded using psymtab_to_symtab
- psymtab_to_symtab calls dwarf2_psymtab::read_symtab
- dwarf2_psymtab::read_symtab calls dwarf2_psymtab::expand_psymtab
- dwarf2_psymtab::read_symtab calls process_cu_includes, and we have the
  includes

In the case of expanding the symtab for dw2-symtab-includes.h:
- the dw2-symtab-includes.h partial symtab is expanded using psymtab_to_symtab
- psymtab_to_symtab calls dwarf2_include_psymtab::read_symtab
- dwarf2_include_psymtab::read_symtab calls
  dwarf2_include_psymtab::expand_psymtab
- dwarf2_include_psymtab::expand_psymtab calls
  partial_symtab::expand_dependencies
- partial_symtab::expand_dependencies calls dwarf2_psymtab::expand_psymtab
  for the CU partial symtab
- the CU partial symtab is expanded using dwarf2_psymtab::expand_psymtab
- process_cu_includes is never called

Fix this by making sure in dwarf2_include_psymtab::read_symtab that
read_symtab is called for the CU partial symtab.

Tested on x86_64-linux, with native, and target board cc-with-dwz and
cc-with-dwz-m.

In addition, tested test-case with target boards cc-with-gdb-index.exp,
cc-with-debug-names.exp and readnow.exp.

gdb/ChangeLog:

2020-04-14  Simon Marchi  <simon.marchi@polymtl.ca>
	    Tom de Vries  <tdevries@suse.de>

	PR symtab/25718
	* psympriv.h (struct partial_symtab::read_symtab)
	(struct partial_symtab::expand_psymtab)
	(struct partial_symtab::read_dependencies): Update comments.
	* dwarf2/read.c (struct dwarf2_include_psymtab::read_symtab): Call
	read_symtab for includer.
	(struct dwarf2_include_psymtab::expand_psymtab): Assert false.
	(struct dwarf2_include_psymtab::readin_p): Call readin_p () for includer.
	(struct dwarf2_include_psymtab::m_readin): Remove.
	(struct dwarf2_include_psymtab::includer): New member function.
	(dwarf2_psymtab::expand_psymtab): Assert !readin.

gdb/testsuite/ChangeLog:

2020-04-14  Tom de Vries  <tdevries@suse.de>

	PR symtab/25718
	* gdb.dwarf2/dw2-symtab-includes.exp: New file.
This commit is contained in:
Tom de Vries 2020-04-14 15:30:50 +02:00
parent c1a66c0629
commit 194d088fb1
5 changed files with 141 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
gdb/ChangeLog
View File

@ -1,3 +1,18 @@
2020-04-14 Simon Marchi <simon.marchi@polymtl.ca>
Tom de Vries <tdevries@suse.de>
PR symtab/25718
* psympriv.h (struct partial_symtab::read_symtab)
(struct partial_symtab::expand_psymtab)
(struct partial_symtab::read_dependencies): Update comments.
* dwarf2/read.c (struct dwarf2_include_psymtab::read_symtab): Call
read_symtab for includer.
(struct dwarf2_include_psymtab::expand_psymtab): Assert false.
(struct dwarf2_include_psymtab::readin_p): Call readin_p () for includer.
(struct dwarf2_include_psymtab::m_readin): Remove.
(struct dwarf2_include_psymtab::includer): New member function.
(dwarf2_psymtab::expand_psymtab): Assert !readin.
2020-04-14 Tom de Vries <tdevries@suse.de>
PR symtab/25720

37
gdb/dwarf2/read.c
View File

@ -5917,22 +5917,31 @@ struct dwarf2_include_psymtab : public partial_symtab
void read_symtab (struct objfile *objfile) override
{
expand_psymtab (objfile);
/* It's an include file, no symbols to read for it.
Everything is in the includer symtab. */
/* The expansion of a dwarf2_include_psymtab is just a trigger for
expansion of the includer psymtab. We use the dependencies[0] field to
model the includer. But if we go the regular route of calling
expand_psymtab here, and having expand_psymtab call expand_dependencies
to expand the includer, we'll only use expand_psymtab on the includer
(making it a non-toplevel psymtab), while if we expand the includer via
another path, we'll use read_symtab (making it a toplevel psymtab).
So, don't pretend a dwarf2_include_psymtab is an actual toplevel
psymtab, and trigger read_symtab on the includer here directly. */
includer ()->read_symtab (objfile);
}
void expand_psymtab (struct objfile *objfile) override
{
if (m_readin)
return;
/* It's an include file, no symbols to read for it.
Everything is in the parent symtab. */
expand_dependencies (objfile);
m_readin = true;
/* This is not called by read_symtab, and should not be called by any
expand_dependencies. */
gdb_assert (false);
}
bool readin_p () const override
{
return m_readin;
return includer ()->readin_p ();
}
struct compunit_symtab *get_compunit_symtab () const override
@ -5941,8 +5950,13 @@ struct dwarf2_include_psymtab : public partial_symtab
}
private:
bool m_readin = false;
partial_symtab *includer () const
{
/* An include psymtab has exactly one dependency: the psymtab that
includes it. */
gdb_assert (this->number_of_dependencies == 1);
return this->dependencies[0];
}
};
/* Allocate a new partial symtab for file named NAME and mark this new
@ -8858,8 +8872,7 @@ process_queue (struct dwarf2_per_objfile *dwarf2_per_objfile)
void
dwarf2_psymtab::expand_psymtab (struct objfile *objfile)
{
if (readin)
return;
gdb_assert (!readin);
expand_dependencies (objfile);

22
gdb/psympriv.h
View File

@ -124,16 +124,26 @@ struct partial_symtab
{
}
/* Read the full symbol table corresponding to this partial symbol
table. */
/* Psymtab expansion is done in two steps:
- a call to read_symtab
- while that call is in progress, calls to expand_psymtab can be made,
both for this psymtab, and its dependencies.
This makes a distinction between a toplevel psymtab (for which both
read_symtab and expand_psymtab will be called) and a non-toplevel
psymtab (for which only expand_psymtab will be called). The
distinction can be used f.i. to do things before and after all
dependencies of a top-level psymtab have been expanded.
Read the full symbol table corresponding to this partial symbol
table. Typically calls expand_psymtab. */
virtual void read_symtab (struct objfile *) = 0;
/* Psymtab expansion is done in two steps. The first step is a call
to read_symtab; but while that is in progress, calls to
expand_psymtab can be made. */
/* Expand the full symbol table for this partial symbol table. Typically
calls expand_dependencies. */
virtual void expand_psymtab (struct objfile *) = 0;
/* Ensure that all the dependencies are read in. */
/* Ensure that all the dependencies are read in. Calls
expand_psymtab for each non-shared dependency. */
void expand_dependencies (struct objfile *);
/* Return true if the symtab corresponding to this psymtab has been

5
gdb/testsuite/ChangeLog
View File

@ -1,3 +1,8 @@
2020-04-14 Tom de Vries <tdevries@suse.de>
PR symtab/25718
* gdb.dwarf2/dw2-symtab-includes.exp: New file.
2020-04-14 Tom de Vries <tdevries@suse.de>
PR symtab/25720

80
gdb/testsuite/gdb.dwarf2/dw2-symtab-includes.exp Normal file
View File

@ -0,0 +1,80 @@
# Copyright 2020 Free Software Foundation, Inc.
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
# Check that symtab user and includes are present after symtab expansion
# triggered by an include file.
load_lib dwarf.exp
# This test can only be run on targets which support DWARF-2 and use gas.
if {![dwarf2_support]} {
return 0
}
standard_testfile main.c .S
# Create the DWARF.
set asm_file [standard_output_file $srcfile2]
Dwarf::assemble $asm_file {
declare_labels partial_label lines_label
global srcdir subdir srcfile
extern main
cu {} {
partial_label: partial_unit {} {
}
}
cu {} {
compile_unit {
{language @DW_LANG_C}
{stmt_list ${lines_label} DW_FORM_sec_offset}
} {
imported_unit {
{import $partial_label ref_addr}
}
}
}
lines {version 2} lines_label {
include_dir "${srcdir}/${subdir}"
file_name "dw2-symtab-includes.h" 1
program {
{DW_LNS_advance_line 1}
}
}
}
if { [prepare_for_testing "failed to prepare" $testfile \
"${asm_file} ${srcfile}" {}] } {
return -1
}
# Check that no symtabs are expanded.
set test "no symtabs expanded"
if { [readnow] } {
unsupported $test
return -1
}
gdb_test_no_output "maint info symtabs" $test
# Expand dw2-symtab-includes.h symtab
gdb_test "maint expand-symtab dw2-symtab-includes.h"
# Check that there are includes.
gdb_test "maint info symtabs" \
"\r\n \\( includes\r\n.*" \
"check symtab includes"