This is needed to avoid linking errors because the globals are placed
in memory at address 0x80000000 which is out of bounds for the default
code model.
It was `avr-atmel-none`, which is incorrect. It must be
`avr-unknown-unknown`.
Additionally, there is no reason to specify the target triple per chip,
it can be done for all AVR chips at once as it doesn't vary like
Cortex-M chips.
This change adds support for `tinygo gdb` on the PCA10056.
The board is normally flashed with the MSD programmer. Debugging needs a
real debugger interface however, which is relatively simple by just
adding the right OpenOCD configuration.
This makes it possible to use Bluetooth on the BBC micro:bit.
Note that you need to use -programmer=cmsis-dap otherwise the SoftDevice
will be erased while flashing something that uses Bluetooth.
The RAM base address is needed during SoftDevice initialization. So far,
the same magic value has been used in aykevl/go-bluetooth and in TinyGo,
but this should be configured in only one place.
This will have additional benefits in the future:
* It is currently set to 0x39c0, which is around 14.5kB. Most nrf51822
chips have only 16kB of RAM, so this is way too much for those
chips.
* LLD in LLVM 11 allows expressions in the MEMORY part of linker
scripts, which will allow overriding the SoftDevice RAM area with a
linker flag, which might come in handy.
Eventually we might want to start using the FPU, but the easy option
right now is to simply disable it everywhere. Previously, it depended on
whether Clang was built as part of TinyGo or it was an external binary.
By setting the floating point mode explicitly, such inconsistencies are
avoided.
This commit creates a new cortex-m4 target which can be the central
place for setting FPU-related settings across all Cortex-M4 chips.
This results in bigger code size, but it works around a bug in the
linker.
The issue starts with the problem that libraries (picolibc, compiler-rt)
were compiled as ARM and the rest as Thumb. This causes some blx
instructions to be inserted by the linker to call into these libraries.
Ideally we should fix the libraries to use Thumb mode instead, but that
requires some more extensive changes (including fixes to compiler-rt)
and it's just way easier to use ARM mode everywhere.
The GC stack scanning code was implemented in the Cortex-M assembly, which meant that it was not available on the GBA which is pre-cortex.
This change adds a copy of the relevant code into a new asembly file which is used on the GBA.
See commit:
54e6ba6724
Warning: this will drop support for Go 1.13 for WebAssembly targets!
I have modified the integration tests to specifically blacklist Go 1.13
instead of whitelisting any other version, to avoid accidentally not
testing WebAssembly.
Unfortunately, `tinygo flash` doesn't work here. You have to merge the
SoftDevice and the application hex with a mergehex tool and flash that
to the board.
This directory is needed for nrf.h and other headers that are used by
the SoftDevice. It is definitely needed for nrf52840 for example, but
I've also added it to the nrf51 as it will likely also require adding
this directory.
The frame pointer was already omitted in the object files that TinyGo
emits, but wasn't yet omitted in the C files it compiles. Omitting the
frame pointer is good for code size (and perhaps performance).
The frame pointer was originally used for printing stack traces in a
debugger. However, advances in DWARF debug info have made it largely
unnecessary (debug info contains enough information now to recover the
frame pointer even without an explicit frame pointer register). In fact,
GDB has been able to produce backtraces in TinyGo compiled code for a
while now while it didn't include a frame pointer.
This is necessary for better CGo support on bare metal. Existing
libraries expect to be able to include parts of libc and expect to be
able to link to those symbols.
Because with this all targets have a working libc, it is now possible to
add tests to check that a libc in fact works basically.
Not all parts of picolibc are included, such as the math or stdio parts.
These should be added later, when needed.
This commit also avoids the need for the custom memcpy/memset/memcmp
symbols that are sometimes emitted by LLVM. The C library will take care
of that.
Somehow I forgot to add this emulator. With this, you can easily emulate
programs:
$ tinygo run -target=atmega1284p examples/serial
Loaded 698 .text at address 0x0
Loaded 12 .data
hello world!..
hello world!..
hello world!..
This convention is followed by most of the avr-gcc toolchain but older
versions of binutils don't mind overlapping program/data spaces.
However, newer versions start complaining about an overlap in address
space:
avr-ld: section .stack VMA [0000000000000100,00000000000002ff] overlaps section .text VMA [0000000000000000,0000000000000225]
This commit moves the data space in the linker script to 0x800000, like
the rest of the toolchain does.
This adds support for the `-scheduler=tasks` flag for AVR. On most AVR
chips you wouldn't want to run a real scheduler but it may be useful in
some cases, especially on devices with more RAM. It is disabled by
default.
Not tested on actual hardware, only on simavr. The main motivation for
adding this chip is to be able to run simulated tests using a much
larger memory space (16kB RAM, 128kB flash) without jumping to the XMega
devices that may not be as well supported by LLVM.
It does not appear to be necessary for these devices but might result in
more appropriate libraries to be linked in.
It is best to _not_ specify the exact MCU because otherwise a few other
settings (such as startfiles and some linker script configs) also get
set, which we do manually anyway and should not be interfered with.
I discovered this while working on support for the atmega1284.
Previously, the RAM was set to start at address 0. This is incorrect: on
AVR, the first few addresses are taken up by memory-mapped I/O. The
reason this didn't lead to problems (yet) was because the stack was
usually big enough to avoid real problems.
There were a few instances like `.text` and `.text*`. The first was
redundant with the second, but the intention was to write `.text.*`.
This doesn't change anything (tested with `make smoketest`) but should
avoid propagating this error in the future.
