[Bug c++/26512] New: 'error reading variable' for char16_t

[Bug c++/26512] New: 'error reading variable' for char16_t

[trass3r at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=26512

            Bug ID: 26512
           Summary: 'error reading variable' for char16_t
           Product: gdb
           Version: HEAD
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c++
          Assignee: unassigned at sourceware dot org
          Reporter: trass3r at gmail dot com
  Target Milestone: ---

$ gdb
GNU gdb (GDB) 10.0.50.20200820-git
...
p (char)70
$1 = 70 'F'

p (char16_t)70
No symbol table is loaded

---

#include <uchar.h>
int main()
{
  char16_t u16 = 0xf000;
  char32_t u32 = 0xf0000000;
  return 0;
}

$ [clan]g++ -g test.cpp -o test
$ gdb -q -ex "br 6" -ex run -ex "p u16" -ex "p u32" -ex cont -ex quit test
gdb: /usr/lib/libtinfo.so.5: no version information available (required by gdb)
+set verbose on
+skip -gfile /usr/include/c++/*/*/*
File(s) /usr/include/c++/*/*/* will be skipped when stepping.
+skip -gfile /usr/include/c++/*/*
File(s) /usr/include/c++/*/* will be skipped when stepping.
+skip -gfile /usr/include/c++/*
File(s) /usr/include/c++/* will be skipped when stepping.
+set print asm-demangle on
+set print vtbl on
+set print symbol on
+set complaints 10
+set trust-readonly-sections on
+set debug timestamp
+set exec-done-display
Reading symbols from test...
+br 6
Reading in symbols for test.cpp...
Breakpoint 1 at 0x64a: file test.cpp, line 6.
+run
Starting program: /tmp/test 
Using PIE (Position Independent Executable) displacement 0x5618978e4000 for
"/tmp/test".
Reading symbols from /lib/ld-linux-x86-64.so.2...
Reading symbols from /lib/.debug/ld-2.27.so...
Reading symbols from system-supplied DSO at 0x7fff703e7000...
(No debugging symbols found in system-supplied DSO at 0x7fff703e7000)
Reading symbols from /usr/lib/libstdc++.so.6...
(No debugging symbols found in /usr/lib/libstdc++.so.6)
Reading symbols from /lib/libm.so.6...
Reading symbols from /lib/.debug/libm-2.27.so...
Reading symbols from /lib/libgcc_s.so.1...
(No debugging symbols found in /lib/libgcc_s.so.1)
Reading symbols from /lib/libc.so.6...
Reading symbols from /lib/.debug/libc-2.27.so...

Breakpoint 1, mainDuring symbol reading: incomplete CFI data; unspecified
registers (e.g., rax) at 0x5618978e464b
During symbol reading: incomplete CFI data; unspecified registers (e.g., rdx)
at 0x5618978e464b
During symbol reading: incomplete CFI data; unspecified registers (e.g., rcx)
at 0x5618978e464b
During symbol reading: incomplete CFI data; unspecified registers (e.g., rbx)
at 0x5618978e464b
During symbol reading: incomplete CFI data; unspecified registers (e.g., rsi)
at 0x5618978e464b
During symbol reading: incomplete CFI data; unspecified registers (e.g., rdi)
at 0x5618978e464b
During symbol reading: incomplete CFI data; unspecified registers (e.g., r8) at
0x5618978e464b
During symbol reading: incomplete CFI data; unspecified registers (e.g., r9) at
0x5618978e464b
During symbol reading: incomplete CFI data; unspecified registers (e.g., r10)
at 0x5618978e464b
During symbol reading: incomplete CFI data; unspecified registers (e.g., r11)
at 0x5618978e464b
 (Reading in symbols for
/usr/src/debug/glibc/2.27-r0/git/sysdeps/x86/libc-start.c...
During symbol reading: cannot get low and high bounds for subprogram DIE at
0x8e0d
) at test.cpp:6
6         return 0;
completed.
+p u16
$1 = 61440 u'<error reading variable>
+p u32
$2 = 4026531840 U'<error reading variable>
+cont
Continuing.
[Inferior 1 (process 10419) exited normally]
completed.
+quit

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[Bug c++/26512] 'error reading variable' for char16_t

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=26512

Tom Tromey <tromey at sourceware dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2020-08-21
                 CC|                            |tromey at sourceware dot org
             Status|UNCONFIRMED                 |WAITING
     Ever confirmed|0                           |1

--- Comment #1 from Tom Tromey <tromey at sourceware dot org> ---
Works for me on Fedora 32 with the system g++:

(gdb) p u16
$1 = 61440 u''
(gdb) p u32
$2 = 4026531840 U'\xf0000000'


Maybe something's wrong with the DWARF in your case.
Could you attach your executable?  Maybe it would help.

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[Bug c++/26512] 'error reading variable' for char16_t

[trass3r at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=26512

trass3r <trass3r at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|WAITING                     |RESOLVED
         Resolution|---                         |INVALID

--- Comment #2 from trass3r <trass3r at gmail dot com> ---
The very same gdb and test executables work in the original build environment
but not in the admittedly weird deployment one.

When I run gdb with LD_LIBRARY_PATH=/lib so it pulls in a different libtinfo.so
and other base libs I get something for u16 at least:
+p u16
$1 = 10003 u'\x2713'
+p u32
$2 = 10003 U'<error reading variable>

Interestingly when using libtinfo.so from the build environment it doesn't
work.
Any pointers to possible causes are still appreciated.

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