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* [Bug symtab/15391] New: DW_OP_GNU_implicit_pointer bug
@ 2013-04-23 12:25 jan.kratochvil at redhat dot com
2013-04-23 15:13 ` [Bug symtab/15391] " tromey at redhat dot com
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: jan.kratochvil at redhat dot com @ 2013-04-23 12:25 UTC (permalink / raw)
To: gdb-prs
http://sourceware.org/bugzilla/show_bug.cgi?id=15391
Bug #: 15391
Summary: DW_OP_GNU_implicit_pointer bug
Product: gdb
Version: HEAD
Status: NEW
Severity: normal
Priority: P2
Component: symtab
AssignedTo: unassigned@sourceware.org
ReportedBy: jan.kratochvil@redhat.com
CC: tromey@redhat.com
Classification: Unclassified
Target: x86_64-unknown-linux-gnu
struct S { short a; char b, c; };
volatile int v;
void foo (int x)
{
struct S s = { x, x + 2, x + 3 };
char *p = &s.b;
s.a++;
v++; /* line 8 */
}
int main ()
{
foo (1);
return 0;
}
gcc-4.8.0-2.fc19.x86_64
gcc -g -O2 -fno-inline -fno-ipa-cp -o implptr implptr.c -Wall
gdb ./implptr -ex 'b 8' -ex r -ex 'p p[-1]' -ex c -ex q -q
Actual:
$1 = 3 '\003'
Expected:
$1 = 0 '\000'
Bugreported by Jakub Jelinek.
Abbrev Number: 7 (DW_TAG_variable)
DW_AT_name : s
DW_AT_location : (DW_OP_breg5 (rdi): 1; DW_OP_stack_value; DW_OP_piece: 2;
DW_OP_breg5 (rdi): 2; DW_OP_stack_value; DW_OP_piece: 1; DW_OP_breg5 (rdi): 3;
DW_OP_stack_value; DW_OP_piece: 1)
Abbrev Number: 7 (DW_TAG_variable)
DW_AT_name : p
DW_AT_location : (DW_OP_GNU_implicit_pointer: <0x88> 2)
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* [Bug symtab/15391] DW_OP_GNU_implicit_pointer bug
2013-04-23 12:25 [Bug symtab/15391] New: DW_OP_GNU_implicit_pointer bug jan.kratochvil at redhat dot com
@ 2013-04-23 15:13 ` tromey at redhat dot com
2013-06-18 18:11 ` cvs-commit at gcc dot gnu.org
2013-06-18 18:12 ` tromey at redhat dot com
2 siblings, 0 replies; 4+ messages in thread
From: tromey at redhat dot com @ 2013-04-23 15:13 UTC (permalink / raw)
To: gdb-prs
http://sourceware.org/bugzilla/show_bug.cgi?id=15391
Tom Tromey <tromey at redhat dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
AssignedTo|unassigned at sourceware |tromey at redhat dot com
|dot org |
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* [Bug symtab/15391] DW_OP_GNU_implicit_pointer bug
2013-04-23 12:25 [Bug symtab/15391] New: DW_OP_GNU_implicit_pointer bug jan.kratochvil at redhat dot com
2013-04-23 15:13 ` [Bug symtab/15391] " tromey at redhat dot com
@ 2013-06-18 18:11 ` cvs-commit at gcc dot gnu.org
2013-06-18 18:12 ` tromey at redhat dot com
2 siblings, 0 replies; 4+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2013-06-18 18:11 UTC (permalink / raw)
To: gdb-prs
http://sourceware.org/bugzilla/show_bug.cgi?id=15391
--- Comment #1 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
CVSROOT: /cvs/src
Module name: src
Changes by: tromey@sourceware.org 2013-06-18 18:11:19
Modified files:
gdb : ChangeLog dwarf2loc.c utils.c utils.h
gdb/testsuite : ChangeLog
gdb/testsuite/gdb.dwarf2: implptrconst.exp
gdb/testsuite/lib: dwarf.exp
Added files:
gdb/testsuite/gdb.dwarf2: implptrpiece.exp
Log message:
Fix PR symtab/15391
PR symtab/15391 is a failure with the DW_OP_GNU_implicit_pointer
feature.
I tracked it down to a logic error in read_pieced_value. The code
truncates this_size_bits according to the type size and offset too
early -- it should do it after taking bits_to_skip into account.
This patch fixes the bug.
While testing this, I also tripped across a latent bug because
indirect_pieced_value does not sign-extend where needed. This patch
fixes this bug as well.
Finally, Pedro pointed out that a previous version implemented sign
extension incorrectly. This version introduces a new gdb_sign_extend
function for this. A couple of notes on this function:
* It has the gdb_ prefix to avoid clashes with various libraries that
felt free to avoid proper namespacing. There is a "sign_extend"
function in a Tile GX header, in an SOM-related BFD header (and in
sh64-tdep.c and as a macro in arm-wince-tdep.c, but those are
ours...)
* I looked at all the sign extensions in gdb and didn't see ones that
I felt comfortable converting to use this function; in large part
because I don't have a good way to test the conversion.
Built and regtested on x86-64 Fedora 18. New test cases included;
this required a minor addition to the DWARF assembler. Note that the
DWARF CU made by implptrpiece.exp uses a funny pointer size in order
to show the sign-extension bug on all platforms.
* dwarf2loc.c (read_pieced_value): Truncate this_size_bits
after taking bits_to_skip into account. Sign extend byte_offset.
* utils.h (gdb_sign_extend): Declare.
* utils.c (gdb_sign_extend): New function.
* gdb.dwarf2/implptrpiece.exp: New file.
* gdb.dwarf2/implptrconst.exp (d): New variable.
Print d.
* lib/dwarf2.exp (Dwarf::_location): Handle DW_OP_piece.
Patches:
http://sourceware.org/cgi-bin/cvsweb.cgi/src/gdb/ChangeLog.diff?cvsroot=src&r1=1.15708&r2=1.15709
http://sourceware.org/cgi-bin/cvsweb.cgi/src/gdb/dwarf2loc.c.diff?cvsroot=src&r1=1.173&r2=1.174
http://sourceware.org/cgi-bin/cvsweb.cgi/src/gdb/utils.c.diff?cvsroot=src&r1=1.300&r2=1.301
http://sourceware.org/cgi-bin/cvsweb.cgi/src/gdb/utils.h.diff?cvsroot=src&r1=1.8&r2=1.9
http://sourceware.org/cgi-bin/cvsweb.cgi/src/gdb/testsuite/ChangeLog.diff?cvsroot=src&r1=1.3696&r2=1.3697
http://sourceware.org/cgi-bin/cvsweb.cgi/src/gdb/testsuite/gdb.dwarf2/implptrpiece.exp.diff?cvsroot=src&r1=NONE&r2=1.1
http://sourceware.org/cgi-bin/cvsweb.cgi/src/gdb/testsuite/gdb.dwarf2/implptrconst.exp.diff?cvsroot=src&r1=1.3&r2=1.4
http://sourceware.org/cgi-bin/cvsweb.cgi/src/gdb/testsuite/lib/dwarf.exp.diff?cvsroot=src&r1=1.9&r2=1.10
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* [Bug symtab/15391] DW_OP_GNU_implicit_pointer bug
2013-04-23 12:25 [Bug symtab/15391] New: DW_OP_GNU_implicit_pointer bug jan.kratochvil at redhat dot com
2013-04-23 15:13 ` [Bug symtab/15391] " tromey at redhat dot com
2013-06-18 18:11 ` cvs-commit at gcc dot gnu.org
@ 2013-06-18 18:12 ` tromey at redhat dot com
2 siblings, 0 replies; 4+ messages in thread
From: tromey at redhat dot com @ 2013-06-18 18:12 UTC (permalink / raw)
To: gdb-prs
http://sourceware.org/bugzilla/show_bug.cgi?id=15391
Tom Tromey <tromey at redhat dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Resolution|--- |FIXED
Target Milestone|--- |7.7
--- Comment #2 from Tom Tromey <tromey at redhat dot com> ---
Fixed.
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2013-04-23 12:25 [Bug symtab/15391] New: DW_OP_GNU_implicit_pointer bug jan.kratochvil at redhat dot com
2013-04-23 15:13 ` [Bug symtab/15391] " tromey at redhat dot com
2013-06-18 18:11 ` cvs-commit at gcc dot gnu.org
2013-06-18 18:12 ` tromey at redhat dot com
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