Summary:
Variadic functions can be treated in the same way as normal functions
with respect to the number and types of parameters.

Reviewers: grosbach, olista01, t.p.northover, rengolin

Subscribers: javed.absar, aemerson, llvm-commits

Differential Revision: https://reviews.llvm.org/D26748

llvm-svn: 287219

of the abi we should be using. For targets that don't use the
option there's no change, otherwise this allows external users
to set the ABI via string and avoid some of the -backend-option
pain in clang.

Use this option to move the ABI for the ARM port from the
Subtarget to the TargetMachine and update the testcases
accordingly since it's no longer valid to set via -mattr.

llvm-svn: 224492

same. This will change the "bare metal" ABI from APCS to AAPCS.

The only difference between the front and back end code is that
the code for Triple::GNU was added for environment. That will migrate
to the front end shortly.

Tests updated with the ABI they were originally testing in the case
of bare metal (e.g. -mtriple armv7) or with a -gnu for arm-linux
triples.

llvm-svn: 224489

Externally-defined functions with weak linkage should not be
tail-called on ARM or AArch64, as the AAELF spec requires normal calls
to undefined weak functions to be replaced with a NOP or jump to the
next instruction. The behaviour of branch instructions in this
situation (as used for tail calls) is implementation-defined, so we
cannot rely on the linker replacing the tail call with a return.

llvm-svn: 215890

Thanks to gix for pointing out that the CHECK-LABEL lines were incorrect!

llvm-svn: 204700

Use the options in the ARMISelLowering to control whether tail calls are
optimised or not.  Previously, this option was entirely ignored on the ARM
target and only honoured on x86.

This option is mostly useful in profiling scenarios.  The default remains that
tail call optimisations will be applied.

llvm-svn: 203577