[Bug target/12007] Multiple inheritance float pass by value fails

["dave at hiauly1 dot hia dot nrc dot ca" <gcc-bugzilla@gcc.gnu.org>]

------- Additional Comments From dave at hiauly1 dot hia dot nrc dot ca  2004-01-19 20:36 -------
Subject: Re:  Multiple inheritance float pass by value f

> The testcase fails on 3.4 hpux 10.20 and 3.5 hpux 11.11, 32-bit SOM
> port.

Ok, the problem is understood.  An indirect call is used to transfer
to the thunk.  Under the HP-UX 32-bit runtime, the first arguments
are passed in general registers.  However, myGv::PutVal(float)
expects its second argument in %fr5.  The linker is supposed to
provide a stub to copy the argument.  However, the .PARAM statement
for the thunk doesn't provide argument location information.  As
a result, the float argument doesn't get copied from %r25 to %fr5.
We also don't provide a .CALL for the transfer from the thunk to
the function.  This is also another potential place where argument
relocation might occur.  The linker doesn't relocate arguments
for this branch as it assumes the arguments are in their default
locations.

The .PARAM statement is generated by ASM_DECLARE_FUNCTION_NAME.
It would appear that the declaration for the thunk doesn't contain
any argument information.  The proper fix is to provide appropriate
argument for the thunk (DECL_ARGUMENTS) as the thunk has no way
of knowing whether it is being called directly or not.  This will
allow the linker to appropriately relocate arguments for both direct
and indirect calls to the thunk.

The hppa-linux ABI is slightly different.  The linker doesn't relocate
arguments.  To compensate, we put floating arguments in both general
and floating point registers for indirect calls.  This avoids the
above problem.  However, the sibcall issue needs fixing.

Dave


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12007