GDB 9+ can't examine any exported D symbols from another module

[Zixing Liu]

GDB 9+ can't examine exported D symbols from another D module when the imported symbol is imported inside a function (subprogram).

[Zixing Liu (liushuyu-011)]

Created attachment 15807
Suggested patch for this issue

This seems to be a regression: GDB 9+ can't examine exported D symbols from another D module when the imported symbol is imported inside a function (subprogram).

For example, in file a.d, we have:

__gshared float b_Glob = 55.22;

In file b.d, we have:

void main()
{
  import a;
  b_Glob = 99.88; // GDB: p b_Glob
  return; //#break
}

When you build the program using:

gdc -ggdb3 -O0 a.d b.d -o a

And then run `gdb ./a` with the following command inputs, and you will see:

(gdb) b b.d:5
Breakpoint 1 at 0x252da: file /tmp/b.d, line 5.
(gdb) r
Starting program: /tmp/a
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/usr/lib/libthread_db.so.1".

Breakpoint 1, D main () at /tmp/b.d:5
5 return; //#break
(gdb) p b_Glob
No symbol "b_Glob" in current context.
(gdb)

With GDB 9, you will see the expected print-out (on amd64) of:

$1 = 99.8799973

-----------------

I suspect this is an issue with how GDB reads imported modules and investigated this to be an accidental regression caused by a refactor to dwarf2/read.c. Please see my suggested patch attached.