This fixes https://github.com/tinygo-org/tinygo/issues/1884.
My original plan to fix this was much more complicated, but then I
realized that the output type doesn't matter anyway and I can simply
cast the type to an *i8 and perform a GEP on that pointer.
On ARM, the stack has to be aligned to 8 bytes on function calls, but
not necessarily within a function. Leaf functions can take advantage of
this by not keeping the stack aligned so they can avoid pushing one
register. However, because regular functions might expect an aligned
stack, the interrupt controller will forcibly re-align the stack when an
interrupt happens in such a leaf function (controlled by the STKALIGN
flag, defaults to on). This means that stack size calculation (as used
in TinyGo) needs to make sure this extra space for stack re-alignment is
available.
This commit fixes this by aligning the stack size that will be used for
new goroutines.
Additionally, it increases the stack canary size from 4 to 8 bytes, to
keep the stack aligned. This is not strictly necessary but is required
by the AAPCS so let's do it anyway just to be sure.
This can be very useful for some purposes:
* It makes it possible to disable the UART in cases where it is not
needed or needs to be disabled to conserve power.
* It makes it possible to disable the serial output to reduce code
size, which may be important for some chips. Sometimes, a few kB can
be saved this way.
* It makes it possible to override the default, for example you might
want to use an actual UART to debug the USB-CDC implementation.
It also lowers the dependency on having machine.Serial defined, which is
often not defined when targeting a chip. Eventually, we might want to
make it possible to write `-target=nrf52` or `-target=atmega328p` for
example to target the chip itself with no board specific assumptions.
The defaults don't change. I checked this by running `make smoketest`
before and after and comparing the results.
This commit implements various process related functions like
os.Getuid() and os.Getpid(). It also implements or improves this support
in the syscall package if it isn't available yet.
This patch adds a new pragma for functions and globals to set the
section name. This can be useful to place a function or global in a
special device specific section, for example:
* Functions may be placed in RAM to make them run faster, or in flash
(if RAM is the default) to not let them take up RAM.
* DMA memory may only be placed in a special memory area.
* Some RAM may be faster than other RAM, and some globals may be
performance critical thus placing them in this special RAM area can
help.
* Some (large) global variables may need to be placed in external RAM,
which can be done by placing them in a special section.
To use it, you have to place a function or global in a special section,
for example:
//go:section .externalram
var externalRAMBuffer [1024]byte
This can then be placed in a special section of the linker script, for
example something like this:
.bss.extram (NOLOAD) : {
*(.externalram)
} > ERAM
These pragmas weren't really tested anywhere, except that some code
might break if they are not properly applied.
These tests make it easy to see they work correctly and also provide a
logical place to add new pragma tests.
I've also made a slight change to how functions and globals are created:
with the change they're also created in the IR even if they're not
referenced. This makes testing easier.
The wasm build tag together with GOARCH=arm was causing problems in the
internal/cpu package. In general, I think having two architecture build
tag will only cause problems (in this case, wasm and arm) so I've
removed the wasm build tag and replaced it with tinygo.wasm.
This is similar to the tinygo.riscv build tag, which is used for older
Go versions that don't yet have RISC-V support in the standard library
(and therefore pretend to be GOARCH=arm instead).
This package provides access to an operating system resource
(cryptographic numbers) and so needs to be replaced with a TinyGo
version that does this in a different way.
I've made the following choices while adding this feature:
- I'm using the getentropy call whenever possible (most POSIX like
systems), because it is easier to use and more reliable. Linux is
the exception: it only added getentropy relatively recently.
- I've left bare-metal implementations to a future patch. This because
it's hard to reliably get cryptographically secure random numbers on
embedded devices: most devices do not have a hardware PRNG for this
purpose.
This was triggered by the following code:
var smallPrimesProduct = new(big.Int).SetUint64(16294579238595022365)
It is part of the new TinyGo version of the crypto/rand package.
This makes it possible to flash a board even when there are multiple
different kinds of boards attached, e.g. an Arduino Uno and a Circuit
Playground Express. You can find the VID/PID pair in several ways:
1. By running `lsusb` before and after attaching the board and looking
at the new USB device.
2. By grepping for `usb_PID` and `usb_VID` in the TinyGo source code.
3. By checking the Arduino IDE boards.txt from the vendor.
Note that one board may have multiple VID/PID pairs:
* The bootloader and main program may have a different PID, so far
I've seen that the main program generally has the bootloader PID
with 0x8000 added.
* The software running on the board may have an erroneous PID, for
example from a different board. I've seen this happen a few times.
* A single board may have had some revisions which changed the PID.
This is particularly true for the Arduino Uno.
As a fallback, if the given VID/PID pair isn't found, the whole set of
serial ports will be used.
There are many boards which I haven't included yet simply because I
couldn't test them.
Previously it was 1024 bytes, which occasionally ran into a stack
overflow. I hope that 2048 bytes will be enough for most purposes.
I've also removed some 2048-byte stack size settings in JSON files,
which are unnecessary now that the parent (cortex-m.json) sets them.
This only works with a custom bossac build from Arduino, not with the
upstream version. It avoids needing the manual "double tap" to enter
bootloader mode before flashing firmware.
Int in Go and C are two different types (hence why CGo has C.int). The
code in syscall assumed they were of the same type, which led to a bug:
https://github.com/tinygo-org/tinygo/issues/1957
While the C standard makes no guarantees on the size of int, in most
modern operating systems it is 32-bits so Go int32 would be the correct
choice.
This commit includes two changes:
* It makes unexported interface methods package-private, so that it's
not possible to type-assert on an unexported method in a different
package.
* It makes the globals used to identify interface methods defined
globals, so that they can (eventually) be left in the program for an
eventual non-LTO build mode.
Previously, flash-command would assume it could execute a command
straight via /bin/sh, at least on non-Windows systems. Otherwise it
would just split the command using `strings.Split`. This is all a bit
hacky, so I've replaced it with a proper solution: splitting the command
_before_ substituting various paths using a real shell splitter
(shlex.Split, from Google). This solves a few things:
* It guards against special characters in path names. This can be an
issue on Windows where the temporary path may contain spaces (this
is uncommon on POSIX systems).
* It is more portable, by disallowing the use of a shell. That way, it
doesn't differentiate between Windows and non-Windows anymore.
Other chips support explicit control of pull-up vs pull-down for GPIO input. Support that with bluepill also. PinInputPullUpDown is maintained for back-compat. It is implicit pull-down.
This was broken because multiple packages in the program were named
'main', even one that was imported (by the generated main package).
This fixes tests for main packages.
Previously a command like the following would incorrectly print FAIL:
tinygo test -c math
This commit fixes this issue by defaulting to a passing test (the test
is marked as passed if it isn't run).
