For example, this commit moves the 'throw' branch of an assertion (nil
check, slice index check, etc) to the end of the function while
inserting the "continue" branch right after the insert location. This
makes the resulting IR easier to follow.
For some reason, this also reduces code size a bit on average. The
TinyGo smoke tests saw a reduction of 0.22%, mainly from WebAssembly.
The drivers repo saw little average change in code size (-0.01%).
This commit also adds a few compiler tests for the defer keyword.
Switch over to LLVM 14 for static builds. Keep using LLVM 13 for regular
builds for now.
This uses a branch of the upstream Espressif branch to fix an issue,
see: https://github.com/espressif/llvm-project/pull/59
There used to be a difference between `byte` and `uint8` in interface
methods. These are aliases, so they should be treated the same.
This patch introduces a custom serialization format for types,
circumventing the `Type.String()` method that is slightly wrong for our
purposes.
This also fixes an issue with the `any` keyword in Go 1.18, which
suffers from the same problem (but this time actually leads to a crash).
This removes the parentHandle argument from the internal calling convention.
It was formerly used to implment coroutines.
Now that coroutines have been removed, it is no longer necessary.
When a package only uses runtime.trackPointer to create interface packs, the compiler fails to find runtime.trackPointer.
This change predeclares it alongside runtime.alloc and updates the tests to use runtime.trackPointer when the test's target uses it.
This adds support for building with `-tags=llvm13` and switches to LLVM
13 for tinygo binaries that are statically linked against LLVM.
Some notes on this commit:
* Added `-mfloat-abi=soft` to all Cortex-M targets because otherwise
nrfx would complain that floating point was enabled on Cortex-M0.
That's not the case, but with `-mfloat-abi=soft` the `__SOFTFP__`
macro is defined which silences this warning.
See: https://reviews.llvm.org/D100372
* Changed from `--sysroot=<root>` to `-nostdlib -isystem <root>` for
musl because with Clang 13, even with `--sysroot` some system
libraries are used which we don't want.
* Changed all `-Xclang -internal-isystem -Xclang` to simply
`-isystem`, for consistency with the above change. It appears to
have the same effect.
* Moved WebAssembly function declarations to the top of the file in
task_asyncify_wasm.S because (apparently) the assembler has become
more strict.
Large object layouts don't fit in a pointer-sized integer and therefore
need to be stored in a global instead. However, the way the data was
stored in these globals was not correct for buffers that don't have
pointers near the end. This commit fixes this issue by using math/big
FillBytes() instead of Bytes().
This gets the unicode package to compile on AVR.
This change swaps the stack chain when switching goroutines, ensuring that the chain is maintained consistently.
This is only really currently necessary with asyncify on wasm.
This change implements a new "scheduler" for WebAssembly using binaryen's asyncify transform.
This is more reliable than the current "coroutines" transform, and works with non-Go code in the call stack.
runtime (js/wasm): handle scheduler nesting
If WASM calls into JS which calls back into WASM, it is possible for the scheduler to nest.
The event from the callback must be handled immediately, so the task cannot simply be deferred to the outer scheduler.
This creates a minimal scheduler loop which is used to handle such nesting.
This PR fixes two bugs at once:
1. Indices were incorrectly extended to a bigger type. Specifically,
unsigned integers were sign extended and signed integers were zero
extended. This commit swaps them around.
2. The getelementptr instruction was given the raw index, even if it
was a uint8 for example. However, getelementptr assumes the indices
are signed, and therefore an index of uint8(200) was interpreted as
an index of int8(-56).
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.
This commit adds object layout information to new heap allocations. It
is not yet used anywhere: the next commit will make use of it.
Object layout information will eventually be used for a (mostly) precise
garbage collector. This is what the data is made for. However, it is
also useful in the interp package which can work better if it knows the
memory layout and thus the approximate LLVM type of heap-allocated
objects.
This layout parameter is currently always nil and ignored, but will
eventually contain a pointer to a memory layout.
This commit also adds module verification to the transform tests, as I
found out that it didn't (and therefore didn't initially catch all
bugs).
This commit simplifies the IR a little bit: instead of calling
pseudo-functions runtime.interfaceImplements and
runtime.interfaceMethod, real declared functions are being called that
are then defined in the interface lowering pass. This should simplify
the interaction between various transformation passes. It also reduces
the number of lines of code, which is generally a good thing.
This adds support for a construct like this:
type foo func(fn foo)
Unfortunately, LLVM cannot create function pointers that look like this.
LLVM only supports named types for structs (not for pointers) and thus
can't add a pointer to a function type of the same type to a parameter
of that function type.
The fix is simple: cast all function pointers to a void function, in
LLVM IR:
void ()*
Raw function pointers are cast to this type before storing, and cast
back to the regular function type before calling. This means that
function parameters will never refer to its own type because raw
function types are fixed at that one type.
Somehow, this does have an effect on binary size in some cases. The
effect is small and goes both ways. On top of that, there is work
underway in LLVM which would make all pointer types opaque (without a
pointee type). This would make this whole commit useless and therefore
should fix any size increases that might happen.
https://llvm.org/docs/OpaquePointers.html
The division and remainder operations were lowered directly to LLVM IR.
This is wrong however because the Go specification defines exactly what
happens on a divide by zero or signed integer overflow and LLVM IR
itself treats those cases as undefined behavior. Therefore, this commit
implements divide by zero and signed integer overflow according to the
Go specification.
This does have an impact on the generated code, but it is surprisingly
small. I've used the drivers repo to test the code before and after, and
to my surprise most driver smoke tests are not changed at all. Those
that are, have only a small increase in code size. At the same time,
this change makes TinyGo more compliant to the Go specification.
This attribute is also set by Clang when it compiles C source files
(unless -fexceptions is set). The advantage is that no unwind tables are
emitted on Linux (and perhaps other systems). It also avoids
__aeabi_unwind_cpp_pr0 on ARM when using the musl libc.
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.
For example, in this code:
type kv struct {
v float32
}
func foo(a *kv) {
type kv struct {
v byte
}
}
Both 'kv' types would be given the same LLVM type, even though they are
different types! This is fixed by only creating a LLVM type once per Go
type (types.Type).
As an added bonus, this change gives a performance improvement of about
0.4%. Not that much, but certainly not nothing for such a small change.
This commit improves make([]T, len) to be closer to upstream Go. The
difference is unlikely to have much real-world effect, but previously
certain make([]T, len) expressions would not result in a slice out of
bounds error in TinyGo while they would have done such a thing in Go
proper. In practice, available RAM is likely to be a bigger limiting
factor.
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.
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.
Do not store the context parameter (which is used for closures and
function pointers) in the goroutine start parameter bundle for direct
functions that don't need a context parameter. This avoids storing the
(undef) context parameter and thus makes the IR to start a new goroutine
simpler in most cases.
This reduces code size in the channel.go and goroutines.go tests.
Surprisingly, all test cases (when compiled with -target=microbit) have
a changed binary, I haven't investigated why but I suppose the codegen
is slightly different for the runtime.run function (which starts the
main goroutine).
Closure variables are allocated in a parent function and are thus never
nil. Don't do a nil check before reading or modifying the value.
This commit results in a slight reduction in code size in some test
cases: calls.go, channel.go, goroutines.go, json.go, sort.go -
presumably wherever closures are used.
Not sure why you would ever do this, but it appears to be allowed by the
Go specification and previously TinyGo would crash with an unhelpful
error message when you would do this. I don't see any practical use of
it.
The implementation simply runs the builtin directly.
This commit adds a test for both WebAssembly and Cortex-M targets (which
use a different way of goroutine lowering) to show how they lower
goroutines. It makes it easier to show how the output changes in future
commits.
The next commit will change the implementation of func values on Linux
as a result of switching to a task-based scheduler. To keep the
compiler/testdata/func.go test working as expected, switch to
WebAssembly tests.
This allows better escape analysis even without being able to see the
entire program. This makes the stack allocation test case more complete
but probably won't have much of an effect outside of that (as the
compiler is able to infer these attributes in the whole-program
functionattrs pass).
There is no good reason for func values to refer to interface type
codes. The only thing they need is a stable identifier for function
signatures, which is easily created as a new kind of globals. Decoupling
makes it easier to change interface related code.
This is basically just a golden test for the "switch" style of func
lowering. The next commit will make changes to this lowering, which will
be visible in the test output.
This commit optimizes string literals and globals by setting the
appropriate alignment and using a nil pointer in zero-length strings.
- Setting the alignment for string values has a surprisingly large
effect, up to around 2% in binary size. I suspect that LLVM will
pick some default alignment for larger byte arrays if no alignment
has been specified and forcing an alignment of 1 will pack all
strings closer together.
- Using nil for zero-length strings also has a positive effect, but
I'm not sure why. Perhaps it makes some optimizations more trivial.
- Always setting the alignment on globals improves code size slightly,
probably for the same reasons setting the alignment of string
literals improves code size. The effect is much smaller, however.
This commit might have an effect on performance, but if it does this
should be tested separately and such a large win in binary size should
definitely not be ignored for small embedded systems.
Sometimes, LLVM may rename named structs when merging modules.
Therefore, we can't rely on typecodeID structs to retain their struct
names.
This commit changes the interface lowering pass to not rely on these
names. The interp package does however still rely on this name, but I
hope to fix that in the future.
This commit adds a new transform that converts reflect Implements()
calls to runtime.interfaceImplements. At the moment, the Implements()
method is not yet implemented (how ironic) but if the value passed to
Implements is known at compile time the method call can be optimized to
runtime.interfaceImplements to make it a regular interface assert.
This commit is the last change necessary to add basic support for the
encoding/json package. The json package is certainly not yet fully
supported, but some trivial objects can be converted to JSON.
