[Bug debug/85887] New: [6.4.1 & 7.3.1 Regression] Missing DW_TAG_lexical_block PC range

["jason.vas.dias at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85887

            Bug ID: 85887
           Summary: [6.4.1 & 7.3.1 Regression] Missing
                    DW_TAG_lexical_block PC range
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: debug
          Assignee: unassigned at gcc dot gnu.org
          Reporter: jason.vas.dias at gmail dot com
  Target Milestone: ---

Bug #55665 has reappeared in builds of the gcc-6-branch and gcc-7-branch SVN 
trees, and its test case ( g++.dg/guality/pr55665.C ) now fails, on my 
up-to-date RHEL7.5 Linux x86_64 system (glibc 2.17, with
either gdb-8.1 built from source or the distro gdb-7.6.1-110.el7:

Under GCC 6.4.1 ( 20180521, SVN revision # 260441, gdb 8.1 ):

After 'make check' fails, cd to $GCC_BUILD_DIR/host-x86_64-linux-gnu/gcc, 
and run:

$ make check-g++ RUNTESTFLAGS='guality.exp=pr55665*'
...
Running /home/devel/OS/gcc-6-branch/gcc/testsuite/g++.dg/guality/guality.exp
...
FAIL: g++.dg/guality/pr55665.C   -O2  line 23 p == 40
FAIL: g++.dg/guality/pr55665.C   -O3 -g  line 23 p == 40

Here is the detailed gcc/testsuite/g++/g++.log extract showing errors:

spawn gdb -nx -nw -quiet -batch -x pr55665.gdb ./pr55665.exe
[?1034hBreakpoint 1 at 0x4007cb: file
/home/devel/OS/gcc-6-branch/gcc/testsuite/g++.dg/guality/pr55665.C, line 23.

Breakpoint 1, A::A (this=0x7fffffffccac, x=<optimized out>) at
/home/devel/OS/gcc-6-branch/gcc/testsuite/g++.dg/guality/pr55665.C:23
23        foo (p);              // { dg-final { gdb-test 23 "p" "40" } }
$1 = 0
$2 = 40
0 != 40
FAIL: g++.dg/guality/pr55665.C   -O2  line 23 p == 40


spawn gdb -nx -nw -quiet -batch -x pr55665.gdb ./pr55665.exe
[?1034hBreakpoint 1 at 0x4007cb: file
/home/devel/OS/gcc-6-branch/gcc/testsuite/g++.dg/guality/pr55665.C, line 23.

Breakpoint 1, A::A (this=0x7fffffffccac, x=<optimized out>) at
/home/devel/OS/gcc-6-branch/gcc/testsuite/g++.dg/guality/pr55665.C:23
23        foo (p);              // { dg-final { gdb-test 23 "p" "40" } }
$1 = 0
$2 = 40
0 != 40
FAIL: g++.dg/guality/pr55665.C   -O3 -g  line 23 p == 40


spawn gdb -nx -nw -quiet -batch -x pr55665.gdb ./pr55665.exe
[?1034hBreakpoint 1 at 0x4007cb: file
/home/devel/OS/gcc-6-branch/gcc/testsuite/g++.dg/guality/pr55665.C, line 23.

Breakpoint 1, A::A (this=0x7fffffffccac, x=<optimized out>) at
/home/devel/OS/gcc-6-branch/gcc/testsuite/g++.dg/guality/pr55665.C:23
23        foo (p);              // { dg-final { gdb-test 23 "p" "40" } }
pr55665.gdb:3: Error in sourced command file:
No symbol "p" in current context.
UNSUPPORTED: g++.dg/guality/pr55665.C   -O2 -flto -fno-use-linker-plugin
-flto-partition=none  line 23 p == 40



spawn gdb -nx -nw -quiet -batch -x pr55665.gdb ./pr55665.exe
[?1034hBreakpoint 1 at 0x400680: file
/home/devel/OS/gcc-6-branch/gcc/testsuite/g++.dg/guality/pr55665.C, line 23.

Breakpoint 1, A::__base_ctor (x=42, this=<synthetic pointer>) at
/home/devel/OS/gcc-6-branch/gcc/testsuite/g++.dg/guality/pr55665.C:23
23        foo (p);              // { dg-final { gdb-test 23 "p" "40" } }
pr55665.gdb:3: Error in sourced command file:
No symbol "p" in current context.
UNSUPPORTED: g++.dg/guality/pr55665.C   -O2 -flto -fuse-linker-plugin
-fno-fat-lto-objects  line 23 p == 40


The tests pass with GCC 4.8.5 (distro compiler).


Perhaps the fix for 4.8.5 has not been ported to 7.3 / 6.4 ? investigating.