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.
This makes viewing the IR easier because parameters have readable names.
This also makes it easier to write compiler tests (still a work in
progress), that work in LLVM 9 and LLVM 10, as LLVM 10 started printing
value names for unnamed parameters.
Previously, a blocking select on a nil channel would result in a nil panic inside the channel runtime code.
This change fixes the nil checks so that the select works as intended.
Previously, the function value lowering pass had special cases for when there were 0 or 1 function implementations.
However, the results of the pass were incorrect in both of these cases.
This change removes the specializations and fixes the transformation.
In the case that there was a single function implementation, the compiler emitted a select instruction to obtain the function pointer.
This selected between null and the implementing function pointer.
While this was technically correct, it failed to eliminate indirect function calls.
This prevented discovery of these calls by the coroutine lowering pass, and caused async function calls to be passed through unlowered.
As a result, the generated code had undefined behavior (usually resulting in a segfault).
In the case of no function implementations, the lowering code was correct.
However, the lowering code was not run.
The discovery of function signatures was accomplished by scanning implementations, and when there were no implementations nothing was discovered or lowered.
For maintainability reasons, I have removed both specializations rather than fixing them.
This substantially simplifies the code, and reduces the amount of variation that we need to worry about for testing purposes.
The IR now generated in the cases of 0 or 1 function implementations can be efficiently simplified by LLVM's optimization passes.
Therefore, there should not be a substantial regression in terms of performance or machine code size.
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.
This makes the result consistent across Go versions, by running a regex
on the CGo output that wraps all single-line functions in a consistent
way.
Originally written by Elliott Sales de Andrade and modified by Ayke van
Laethem.
The coroutine lowering pass had issues where it iterated over maps, sometimes resulting in non-deterministic output.
This change removes many of the maps and ensures that the transformations are deterministic.
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.
See comment in the commit for details. It works around a bug that's been
reported here: https://bugs.llvm.org/show_bug.cgi?id=45336
This is a separate commit so it can easily be reverted if/when this
patch is backported to the LLVM 10 stable branch.
This commit also adds a bit of version independence, in particular for
external commands. It also adds the LLVM version to the `tinygo version`
command, which might help while debugging.
Previously, the typecode was passed via a direct reference, which results in invalid IR when the defer is not reached in all return paths.
It also results in incorrect behavior if the defer is in a loop, causing all defers to use the typecode of the last iteration.
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.
The main change is in building the libraries, where -fshort-enums was
passed on RISC-V while other C files weren't compiled with this setting.
Note: the test already passed before this change, but it seems like a
good idea to explicitly test for enum size consistency.
There is also not a particular reason not to pass -fshort-enums on
RISC-V. Perhaps it's better to do it there too (on baremetal targets
that don't have to worry about binary compatibility).
Calling errors.New in an error path causes a heap allocation at an
already unfortunate moment. It is more efficient to create these error
values in globals and return these constant globals. If these errors are
not used (because the related code was optimized out), the globals will
also be optimized out.
This is the kind that is used in Go (actually CGo) for exporting
functions. I think it's best to use //export instead of our custom
//go:export pragma, for consistency (they are equivalent in TinyGo).
Therefore I've updated all instances to the standard format (except for
two that are updated in https://github.com/tinygo-org/tinygo/pull/1024).
No smoke tests changed (when comparing the output hash), except for some
wasm tests that include DWARF debug info and tend to be flaky anyway.
This is a very common case. Avoiding a runtime.interfaceEqual call leads
to a very big reduction in code size in some cases (while it doesn't
affect many other examples). A number of driver smoke tests are reduced
by about 4kB just with this optimization.
I found this issue while looking into automatically calculating the
required amount of stack space for goroutines. The
runtime.interfaceEqual function is recursive, so it is best avoided.
This is necessary because LLVM defines many options in global variables
that are modified when invoking Clang. In particular, LLVM 10 seems to
have a bug in which it always sets the -pgo-warn-misexpect flag. Setting
it multiple times (over various cc1 invocations) results in an error:
clang (LLVM option parsing): for the --pgo-warn-misexpect option: may only occur zero or one times!
This is fixed by running the Clang invocation in a new `tinygo`
invocation.
Because we've had issues with lld in the past, also run lld in a
separate process so similar issues won't happen with lld in the future.
Yannis Huber
Jaden Weiss
Ayke van Laethem
Ron Evans
suzuki-koya
Elliott Sales de Andrade
Yannis Huber
BCG