Re: expand-symtabs.exp

[Mark Kettenis <mark.kettenis@xs4all.nl>]

> Date: Sun, 27 Jan 2008 10:38:02 -0500
> From: Daniel Jacobowitz <drow@false.org>
> 
> On Sun, Jan 27, 2008 at 04:28:22PM +0100, Mark Kettenis wrote:
> > The new expand-psymtabs.exp consistently fails on all systems I try it
> > on with something like:
> > 
> > 
> > (gdb) break 32
> > No line 32 in file "../../../../src/gdb/gdb/testsuite/gdb.base/expand-psymtabs.c".
> > (gdb) FAIL: gdb.base/expand-psymtabs.exp: Expand psymtabs
> > 
> > 
> > Looking at the source code for this test, GDB's respnse here is quite
> > reasonable, since line 32 is the line withe the comment /* Break here
> > */ in the code fragment below:
> 
> GDB's historical behavior in that case is to set a breakpoint on the
> next line, and there ought to be code for the next line (the
> epilogue).  It looks like you're hitting the bug the testcase was
> written for.  Does break 32 work with -readnow?

Nope.  And there is no line number info for the epilogue.  As far as I
know, GCC never generated such info, so it must be something that's
new in GCC 4.

(gdb) disas foo
Dump of assembler code for function foo:
0x00000000004007e0 <foo+0>:     push   %rbp
0x00000000004007e1 <foo+1>:     mov    %rsp,%rbp
0x00000000004007e4 <foo+4>:     leaveq 
0x00000000004007e5 <foo+5>:     retq   
End of assembler dump.

...

$ readelf -wl expand-symtabs

...

 Line Number Statements:
  Extended opcode 2: set Address to 0x4007e0
  Advance Line by 30 to 31
  Copy
  Special opcode 61: advance Address by 4 to 0x4007e4 and Line by 0 to 31
  Advance PC by 2 to 4007e6
  Extended opcode 1: End of Sequence