[Bug c++/21222] A function with VEX encoded SSE instructions and a particular number of arguments corrupts a value calculated on the stack when stepping through the function

["kungfujesus06 at gmail dot com" <sourceware-bugzilla at sourceware dot org>]

https://sourceware.org/bugzilla/show_bug.cgi?id=21222

--- Comment #19 from Adam Stylinski <kungfujesus06 at gmail dot com> ---
(In reply to Adam Stylinski from comment #18)
> (In reply to Adam Stylinski from comment #17)
> > (In reply to Pedro Alves from comment #16)
> > > (In reply to Adam Stylinski from comment #15)
> > > 
> > > > Sure, can you send me a link to the repo?
> > > 
> > > https://sourceware.org/gdb/current/
> > > 
> > > > Your workaround seems to be correct, so there's a good chance your fix will
> > > > work:
> > > 
> > > Awesome, that's a very good indication indeed.
> > 
> > Hmm, getting a build error:
> > 
> > target-descriptions.c: In member function ‘virtual void
> > print_c_tdesc::visit_pre(const target_desc*)’:
> > target-descriptions.c:1836:16: error: types may not be defined in a
> > for-range-declaration [-Werror]
> >      for (const struct bfd_arch_info *compatible : e->compatible)
> >                 ^~~~~~
> 
> I think I may have fixed this build error, modified the type to be something
> that was already declared as a type (const bfd_arch_info_type*).  My guess
> is at some point this struct was typedef'd to this and meant to be used this
> way.  I'll let you know if this version fixes it.

adam@eggsbenedict ~/scratch/binutils-gdb/gdb $ ./gdb ~/test.out 
Exception caught while booting Guile.
Error in function "open-file":
No such file or directory: "/usr/share/gdb/guile/gdb/boot.scm"
./gdb: warning: Could not complete Guile gdb module initialization from:
/usr/share/gdb/guile/gdb/boot.scm.
Limited Guile support is available.
Suggest passing --data-directory=/path/to/gdb/data-directory.

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Reading symbols from /home/adam/test.out...done.
(gdb) break testFunc
Breakpoint 1 at 0x400530: file test.cpp, line 12.
(gdb) r
Starting program: /home/adam/test.out 

Breakpoint 1, testFunc (a=0x0, n=0, sx=0x0, sy=0x0, rc=0x0, nr=0, b=4,
f=9.50000026e+09, c=0x0, d=0x0, e=0x0, gx=0x0, gy=0x0, gz=0x0) at test.cpp:12
12          float lambda = C_LIGHT / f;
(gdb) n
13          printf("lambda = %f\n", lambda);
(gdb) 
lambda = 0.031557
14      }
(gdb) n
main () at test.cpp:21
21          return 0;
(gdb) c
Continuing.
[Inferior 1 (process 1119) exited normally]
(gdb) set displaced-stepping on
(gdb) r
Starting program: /home/adam/test.out 

Breakpoint 1, testFunc (a=0x0, n=0, sx=0x0, sy=0x0, rc=0x0, nr=0, b=4,
f=9.50000026e+09, c=0x0, d=0x0, e=0x0, gx=0x0, gy=0x0, gz=0x0) at test.cpp:12
12          float lambda = C_LIGHT / f;
(gdb) n
13          printf("lambda = %f\n", lambda);
(gdb) 
lambda = 0.031557
14      }
(gdb) 
main () at test.cpp:21
21          return 0;
(gdb) c
Continuing.
[Inferior 1 (process 1186) exited normally]

Looks good.

Here's a patch for that build error, though I assume someone will eventually
catch this:

diff --git a/gdb/target-descriptions.c b/gdb/target-descriptions.c
index 5a6f61945d..363ddf5ac6 100644
--- a/gdb/target-descriptions.c
+++ b/gdb/target-descriptions.c
@@ -1832,8 +1832,7 @@ public:
           gdbarch_osabi_name (tdesc_osabi (e)));
        printf_unfiltered ("\n");
       }
-
-    for (const struct bfd_arch_info *compatible : e->compatible)
+    for (const bfd_arch_info_type *compatible : e->compatible)
       printf_unfiltered
        ("  tdesc_add_compatible (result, bfd_scan_arch (\"%s\"));\n",
         compatible->printable_name);

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