Re: [PATCH] Fix gdb.ada/O2_float_param.exp for PowerPC

[Carl Love <cel@us.ibm.com>]

On Fri, 2023-08-04 at 10:05 -0600, Tom Tromey wrote:
<snip>
> 
> Carl> +    # Note, on PowerPC the output line looks like:
> Carl> +    # #0  0x0000000010010a88 in callee.increment (
> val=val@entry=99.0, msg=...)
> Carl> +    # Not all architectures print the address.
> 
> I don't think this is architecture-dependent.  Instead, something
> else
> is going wrong here.  Why exactly is it printing the address?  The
> code
> here looks like:
> 
>     if (opts.addressprint)
>       if (!sal.symtab
> 	  || frame_show_address (frame, sal)
> 	  || print_what == LOC_AND_ADDRESS)
> 
> Could it maybe be different inlining decisions?
> Maybe seeing which of those clauses is true would show the answer.
> 
> I don't mind working around differences like this by patching the
> tests,
> but I would like the real cause to be known and put into the comment.

OK, I was able to get Ada installed on my X86 laptop so I could put in
debug prints on PowerPC and X86-64.  Thanks for the help identifying
where the print occurs.  

The function frame_show_address (frame, sal) returns true on PowerPC. 
The return statement for frame_show_address (frame, sal) is

   return get_frame_pc (frame) != sal.pc || !sal.is_stmt;

On PowerPC sal.is_stmt is false for this test but it is true on X86-64.

The result is the code you gave above, from print_frame in gdb/stack.c,
evaluates to true and the address is printed on PowerPC.

I updated the comment in the patch as:

+    # If sal.is_stmt is false for the frame, function frame_show_address will
+    # return true and function print_frame in gdb/stack.c will print the
+    # address.  In this case, the output will look something like:
+    # #0  0x0000000010010a88 in callee.increment (val=val@entry=99.0, msg=...)
+    # This situation currently occurs on PowerPC but not on X86-64.
+    # The re string needs to account for the possibility that the address
+    # will be printed.
     set re \
-	"#0\\s+callee\\.increment \\(val(=val@entry)?=99\\.0, msg=\\.\\.\\.\\).*"
+	"#0.*callee\\.increment \\(val(=val@entry)?=99\\.0, msg=\\.\\.\\.\\).*"
     set re_different_entry_val \

to describe when the address is printed.  I noted that the address is
printed when sal.is_stmt is false as is currently the case on PowerPC. 

I will post version two of the patch for review.

Thanks for the help on this patch.

                                 Carl