This commit adds support for LLVM 16 and switches to it by default. That
means three LLVM versions are supported at the same time: LLVM 14, 15,
and 16.
This commit includes work by QuLogic:
* Part of this work was based on a PR by QuLogic:
https://github.com/tinygo-org/tinygo/pull/3649
But I also had parts of this already implemented in an old branch I
already made for LLVM 16.
* QuLogic also provided a CGo fix here, which is also incorporated in
this commit:
https://github.com/tinygo-org/tinygo/pull/3869
The difference with the original PR by QuLogic is that this commit is
more complete:
* It switches to LLVM 16 by default.
* It updates some things to also make it work with a self-built LLVM.
* It fixes the CGo bug in a slightly different way, and also fixes
another one not included in the original PR.
* It does not keep compiler tests passing on older LLVM versions. I
have found this to be quite burdensome and therefore don't generally
do this - the smoke tests should hopefully catch most regressions.
This flag is necessary in LLVM 15 because it appears that LLVM 15 has
changed the default target ABI from lp64 to lp64d. This results in a
linker failure. Setting the "target-abi" forces the RISC-V backend to
use the intended target ABI.
The target triples have to match mostly to be able to link LLVM modules.
Linking LLVM modules is already possible (the triples already match),
but testing becomes much easier when they match exactly.
For macOS, I picked "macosx10.12.0". That's an old and unsupported
version, but I had to pick _something_. Clang by default uses
"macos10.4.0", which is much older.
You can now debug the ESP32-C3 from the TinyGo command line, like this:
tinygo flash -target=esp32c3 examples/serial
tinygo gdb -target=esp32c3 examples/serial
It's important to flash before running `tinygo gdb`, because loading a
new firmware from GDB has not yet been implemented.
Probably the easiest way to connect to the ESP32-C3 is by using the
built-in JTAG connection. See:
https://docs.espressif.com/projects/esp-idf/en/latest/esp32c3/api-guides/jtag-debugging/configure-builtin-jtag.html
You will need to make sure that the `openocd` command in your $PATH is
the one from Espressif. Otherwise GDB will hang. You can debug this by
supplying the -ocd-output flag:
$ tinygo gdb -target=esp32c3 -ocd-output examples/serial
Open On-Chip Debugger 0.10.0
openocd: Licensed under GNU GPL v2
openocd: For bug reports, read
openocd: http://openocd.org/doc/doxygen/bugs.html
openocd: embedded:startup.tcl:60: Error: Can't find interface/esp_usb_jtag.cfg
openocd: in procedure 'script'
openocd: at file "embedded:startup.tcl", line 60
Make sure to configure OpenOCD correctly, until you get the correct
version (that includes the string "esp32"):
$ openocd --version
Open On-Chip Debugger v0.10.0-esp32-20210721 (2021-07-21-13:33)
Licensed under GNU GPL v2
For bug reports, read
http://openocd.org/doc/doxygen/bugs.html
If you are on Linux, you may also get the following error:
$ tinygo gdb -target=esp32c3 -ocd-output examples/serial
Open On-Chip Debugger v0.10.0-esp32-20210721 (2021-07-21-13:33)
openocd: Licensed under GNU GPL v2
openocd: For bug reports, read
openocd: http://openocd.org/doc/doxygen/bugs.html
openocd: Info : only one transport option; autoselect 'jtag'
openocd: adapter speed: 40000 kHz
openocd:
openocd: Warn : Transport "jtag" was already selected
openocd: Info : Listening on port 6666 for tcl connections
openocd: Info : Listening on port 4444 for telnet connections
openocd: Error: libusb_open() failed with LIBUSB_ERROR_ACCESS
openocd: Error: esp_usb_jtag: could not find or open device!
The error LIBUSB_ERROR_ACCESS means that there is a permission error.
You can fix this by creating the following file:
$ cat /etc/udev/rules.d/50-esp.rules
# ESP32-C3
SUBSYSTEMS=="usb", ATTRS{idVendor}=="303a", ATTRS{idProduct}=="1001", MODE="0666"
For more details, see:
https://docs.espressif.com/projects/esp-idf/en/latest/esp32c3/api-guides/jtag-debugging/index.html
This commit changes a target triple like "armv6m-none-eabi" to
"armv6m-unknown-unknow-eabi". The reason is that while the former is
correctly parsed in Clang (due to normalization), it wasn't parsed
correctly in LLVM meaning that the environment wasn't set to EABI.
This change normalizes all target triples and uses the EABI environment
(-eabi in the triple) for Cortex-M targets.
This change also drops the `--target=` flag in the target JSON files,
the flag is now added implicitly in `(*compileopts.Config).CFlags()`.
This removes some duplication in target JSON files.
Unfortunately, this change also increases code size for Cortex-M
targets. It looks like LLVM now emits calls like __aeabi_memmove instead
of memmove, which pull in slightly more code (they basically just call
the regular C functions) and the calls themself don't seem to be as
efficient as they could be. Perhaps this is a LLVM bug that will be
fixed in the future, as this is a very common occurrence.
