Achievements:
Some progress on Range Thunks. [TCWG-614]
- I have all the enabling patches that allow assignAddresses() to be
run multiple times committed.
- Need review for the actual range thunks implementation itself.
Compiler-rt [TCWG-1156]
- Clang (as opposed to llvm) is assuming that all builtins for ARM are
mandated to have a soft-float interface. I have a tentative patch but
need to test it a bit more first.
- Found out a bit more about the structure of how compiler-rt, and why
it behaves differently when I use the default target and
auto-detection of toolkit as opposed to supplying the target via
options.
-- There is quite a bit of hidden magic and hacks going on in the
default case, some of it I don't think is quite right. For example
Compiler-rt seems to conflate architecture with abi.
Set myself the task of getting compiler-rt tests running on v6-m with
testing on qemu.
- v6-m is the only auto-detected default target that I haven't been
able to reproduce results on.
- A review claimed that tests had been run on qemu, and I'm now trying
to work out how to reproduce this with clang and an arm-none-eabi
sysroot.
-- Not having a lot of luck so far, latest qemu only supports
emulation of 2 cortex-m3 dev-boards and I have yet to make a
standalone program that works [*]
-- I'm not looking forward to plumbing in the options to make the
arm-none-eabi testing work.
[*] I thought I would try semi-hosting first, but it turns out the
default semihosting startup code supplied with arm-none-eabi replaces
my heap and stack locations with a semi-hosting call to get top of
memory which qemu gives an inappropriate result for a dev-board
emulation with non contiguous memory. Would like to see if I can get
this working via a quick experiment to rewrite the start-up code,
although for the full tests I may fall back to retargeting the IO via
an emulated serial port.
Plans:
- First priority is range thunks for lld
- Second priority is getting a v6m test of compiler-rt to check for
any latent problems
- Submit clang patch when I know it works for all the supported platforms
- Look into v7-m support, particularly v7-m + single precision floating point.