Be able to run `tinygo gdb -target=arduino examples/serial` and debug a
program with the power of a real debugger.
Note that this only works on LLVM 11 because older versions have a bug
in the AVR backend that cause it to produce invalid debug information:
https://reviews.llvm.org/D74213.
This commit switches to LLVM 11 for builds with LLVM linked statically
(e.g. `make`). It does not yet switch the default for builds dynamically
linked to LLVM, that should be done in a later change.
This commit also changes to use the default host toolchain (probably
GCC) instead of Clang as the default compiler in CI. There were some
issues with Clang 3.8 in CI and hopefully this will fix it.
Additionally it updates the way LLVM is built on Windows, with
-DLLVM_ENABLE_PIC=OFF (which should have been used all along). This
change makes it possible to revert a hack to build libclang manually and
instead uses the libclang static library like on all other operating
systems, simplifying the Makefile.
I have chosed to call this implementation `esp8266` instead of `xtensa`
as it has been written specifically for the ESP8266 and there are no
other Xtensa chips with the CALL0 ABI (no windowing) that I know of. The
only other related chip is the ESP32, which does implement register
windowing and thus needs a very different implementation.
This has been a *lot* of work, trying to understand the Xtensa windowed
registers ABI. But in the end I managed to come up with a very simple
implementation that so far seems to work very well.
I tested this with both blinky examples (with blinky2 slightly edited)
and ./testdata/coroutines.go to verify that it actually works.
Most development happened on the ESP32 QEMU fork from Espressif
(https://github.com/espressif/qemu/wiki) but I also verified that it
works on a real ESP32.
The Cortex-M target isn't much changed, but much of the logic for the
AVR stack switcher that was previously in assembly has now been moved to
Go to make it more maintainable and in fact smaller in code size. Three
functions (tinygo_getCurrentStackPointer, tinygo_switchToTask,
tinygo_switchToScheduler) have been changed to one: tinygo_swapTask.
This reduction in assembly code should make the code more maintainable
and should make it easier to port stack switching to other
architectures.
I've also moved the assembly files to src/internal/task, which seems
like a more appropriate location to me.
Unfortunately, CircleCI doesn't seem to provide Debian stretch builds
with Go 1.15. We should be using Debian stretch (an older distro) to
make sure the tinygo binary runs on as many Linux systems as possible
(including older ones), and I think using Go 1.14 for these builds is
unfortunate but the better tradeoff.
On Fedora 33+, there is a buggy package that installs to
`/usr/lib64/clang/{version}/lib`, even on 32-bit systems. The original
code sees the `/usr/lib64/clang/{version}` directory, checks for an
`include` subdirectory, and then gives up because it doesn't exist.
To be more robust, check both `/usr/lib64/clang/{version}/include` and
`/usr/lib/clang/{version}/include`, and only allow versions that match
the LLVM major version used to build tinygo.
* Heap allocation based on available ram
* Added homebrew launcher parser (for overriden heap)
* Removed unused stuff (moved to gonx)
* Kept require code at minimum to work in a real device
* Moved everything to a single file
This fixes an issue where a normal suspending call followed by a plain tail call would result in the tail return value being written to the return pointer of the normal suspending call.
This is fixed by saving the return pointer at the start of the function and restoring it before initiating a plain tail call.
Unfortunately, the .rodata section can't be stored in flash. Instead, an
explicit .progmem section should be used, which is supported in LLVM as
address space 1 but not exposed to normal programs.
Eventually a pass should be written that converts trivial const globals
of which all loads are visible to be in addrspace 1, to get the benefits
of storing those globals directly in ROM.
This appears to be allowed by the specification, at least it is allowed
by the main Go implementation: https://play.golang.org/p/S8jxAMytKDB
Allow it in TinyGo too, for consistency.
Found because it is triggered with `tinygo test flags`. This doesn't
make the flags package pass all tests, but is a step closer.
os.Getenv() was already stubbed out, but os.LookupEnv() wasn't. This
will allow me to compile my program unmodified without using separate
files and build tags.
