Do not try to use the ExectutionEngine of Go, instead compile the
program in the conventional way and run the binary.
This fixes some code duplication that causes slight (but problematic)
misbehavior between `tinygo build` and `tinygo run`.
This was necessary before, when only some functions had a context
parameter. Now this is not necessary anymore because all functions
(independent of signature) have a context paramter at the end so the
signature always automatically matches.
This commit does two things:
* It adds support for the GOOS and GOARCH environment variables. They
fall back to runtime.GO* only when not available.
* It adds support for 3 new architectures: 386, arm, and arm64. For
now, this is Linux-only.
* all: add support for specifying target CPU in target config
* avr: specify the chip name in the target CPU
This reduces code size by a large margin. For examples/blinky, it
reduces code size from 1360 to 1266 when compiling for the Arduino Uno
(94 bytes, or ~7%).
By running these interprocedural optimizations after interface lowering,
in particular the heap-to-stack transformation pass, interfaces can be
zero cost in some more cases.
For example, say you have the following interface:
type Writer interface {
Write([]byte) (int, error)
}
and you do something with it:
func foo(w io.Writer) {
w.Write([]byte("foo"))
}
this commit enables escape analysis across interface boundaries, which
means that the Write call does not cause an allocation if all
implementations of io.Writer do not let the slice escape. This enables
broader uses of interfaces, as they are now a zero-cost abstraction in
more cases.
This reduces complexity in the compiler without affecting binary sizes
too much.
Cortex-M0: no changes
Linux x64: no changes
WebAssembly: some testcases (calls, coroutines, map) are slightly bigger
Implement defer in a different way, which results in smaller binaries.
The binary produced from testdata/calls.go (the only test case with
defer) is reduced a bit in size, but the savings in bytes greatly vary
by architecture:
Cortex-M0: -96 .text / flash
WebAssembly: -215 entire file
Linux x64: -32 .text
Deferred functions in TinyGo were implemented by creating a linked list
of struct objects that contain a function pointer to a thunk, a pointer
to the next object, and a list of parameters. When it was time to run
deferred functions, a helper runtime function called each function
pointer (the thunk) with the struct pointer as a parameter. This thunk
would then in turn extract the saved function parameter from the struct
and call the real function.
What this commit changes, is that the loop to call deferred functions is
moved into the end of the function (practically inlining it) and
replacing the thunks with direct calls inside this loop. This makes it
much easier for LLVM to perform all kinds of optimizations like inlining
and dead argument elimination.
The default priority is 0 (highest) which is reserved by the SoftDevice.
For normal operation the exact priority level doesn't matter, only the
relative priority matters. So this change makes the code compatible with
the SoftDevice without actually changing the behavior.
