This commit lets the compiler know about interrupts and allows
optimizations to be performed based on that: interrupts are eliminated
when they appear to be unused in a program. This is done with a new
pseudo-call (runtime/interrupt.New) that is treated specially by the
compiler.
This results in a link error in the following commit (undefined
reference to runtime.trackedGlobalsBitmap from .debug_info). Solution:
don't emit debug info for declared but not defined symbols.
This reduces code size in a few cases when tested against the drivers
smoketests (although there was one minor increase) without significantly
increasing compile time. In fact, in my testing compile time appears to
be going down a little bit (around 1%, within the noise).
Add location information (whenever possible) to failed imports. This
helps in debugging where an incorrect import came from.
For example, show the following error message:
/home/ayke/src/github.com/tinygo-org/tinygo/src/machine/machine.go:5:8: cannot find package "foobar" in any of:
/usr/local/go/src/foobar (from $GOROOT)
/home/ayke/src/foobar (from $GOPATH)
Instead of the following:
error: cannot find package "foobar" in any of:
/usr/local/go/src/foobar (from $GOROOT)
/home/ayke/src/foobar (from $GOPATH)
This commit fixes a crash when trying to compile the following (invalid)
code:
package main
import "unsafe"
func main() {
}
type Foo struct {
x DoesNotExist
}
const foo = unsafe.Sizeof(Foo{})
This commit fixes this situation. The result is a regular error message,
indicating that DoesNotExist is not defined.
This commit makes a number of changes:
* It avoids a dependency on Compiler.emitStartGoroutine.
* It moves the func-lowering pass to the transform package.
* It adds testing to func lowering.
No functionality should have changed with this commit.
This code is required by transformation passes which are being moved
into a separate package, but is too complicated to simply copy.
Therefore, I decided to move them into a new package.
Instead of putting the magic in the AST, generate regular accessor
methods. This avoids a number of special cases in the compiler, and
avoids missing any of them.
The resulting union accesses are somewhat clunkier to use, but the
compiler implementation has far less coupling between the CGo
implementation and the IR generator.
Move most of the logic of determining which compiler configuration to
use (such as GOOS/GOARCH, build tags, whether to include debug symbols,
panic strategy, etc.) into the compileopts package. This makes it a
single source of truth for anything related to compiler configuration.
It has a few advantages:
* The compile configuration is independent of the compiler package.
This makes it possible to move optimization passes out of the
compiler, as they don't rely on compiler.Config anymore.
* There is only one place to look if an incorrect compile option is
used.
* The compileopts provides some resistance against unintentionally
picking the wrong option, such as with c.selectGC() vs c.GC() in the
compiler.
* It is now a lot easier to change compile options, as most options
are getters now.
When using reflect, arbitrary types can be synthesized. This invalidates
a few assumptions in the interface-lowering pass, that think they can
see all types that are in use in a program and optimize accordingly.
The file size impact depends on the specific program. Sometimes it's
nonexistent, sometimes it's rather hefty (up to 30% bigger). Especially
the samd21 targets seem to be affected, with a 2000-6000 bytes increase
in code size. A moderately large case (the stdlib test) increases by
4%/6%/15% depending on the target.
I hope that this increase could be mitigated, but I don't see an obvious
way to do that.
Previously, the cycle was broken by inserting an unsafe.Pointer type in
some places. This is of course incorrect, and makes debugging harder.
However, LLVM provides a way to make temporary nodes that are later
replaced, exactly for this purpose.
This commit uses those temporary metadata nodes to allow such recursive
types.
Unfortunately, while doing this I found that it doesn't actually apply
in any real-world programs (tested with `make smoketest`), apparently
because nil pointer checking messes with the functionattrs pass. I hope
to fix that after moving to LLVM 9, which has an optimization that makes
nil pointer checking easier to implement.
Also add unit tests.
This is the first of several transformation (optimization/lowering)
passes that I'd like to move to the new transform package. This
separates the compiler from the optimizer.
Also, it finally adds unit tests for the compiler, not just end-to-end
compilation tests. This should improve robustness and should make it
easier to change these transformation passes in the future.
While the heap-to-stack transform is relatively simple, other passes are
much more complex. Adding unit tests not only helps robustness over
time, but also doubles as documentation as to what these transformation
passes do exactly.
This commit allows starting a new goroutine directly from a func value,
not just when the static callee is known.
This is necessary to support the whole time package, not just the
commonly used subset that was compiled with the SimpleDCE pass enabled.
A bug was introduced in the previous commit that led to miscompilations
in the time.Sleep function when the scheduler was disabled, because
time.Sleep (implemented in the runtime) tried to switch to the scheduler
stack.
This commit restores the binary size of most examples to what it was
before, but still reduces static RAM consumption (.bss) slightly. This
gives me some confidence that it does indeed fix the introduced bug.
This scheduler is intended to live along the (stackless) coroutine based
scheduler which is needed for WebAssembly and unsupported platforms. The
stack based scheduler is somewhat simpler in implementation as it does
not require full program transform passes and supports things like
function pointers and interface methods out of the box with no changes.
Code size is reduced in most cases, even in the case where no scheduler
scheduler is used at all. I'm not exactly sure why but these changes
likely allowed some further optimizations somewhere. Even RAM is
slightly reduced, perhaps some global was elminated in the process as
well.
