The math package uses routines written in Go assembly language which
LLVM/Clang cannot parse. Additionally, not all instruction sets are
supported.
Redirect all math functions written in assembly to their Go equivalent.
This is not the fastest option, but it gets packages requiring math
functions to work.
Before this commit, goroutine support was spread through the compiler.
This commit changes this support, so that the compiler itself only
generates simple intrinsics and leaves the real support to a compiler
pass that runs as one of the TinyGo-specific optimization passes.
The biggest change, that was done together with the rewrite, was support
for goroutines in WebAssembly for JavaScript. The challenge in
JavaScript is that in general no blocking operations are allowed, which
means that programs that call time.Sleep() but do not start goroutines
also have to be scheduled by the scheduler.
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
This commit changes many things:
* Most interface-related operations are moved into an optimization
pass for more modularity. IR construction creates pseudo-calls which
are lowered in this pass.
* Type codes are assigned in this interface lowering pass, after DCE.
* Type codes are sorted by usage: types more often used in type
asserts are assigned lower numbers to ease jump table construction
during machine code generation.
* Interface assertions are optimized: they are replaced by constant
false, comparison against a constant, or a typeswitch with only
concrete types in the general case.
* Interface calls are replaced with unreachable, direct calls, or a
concrete type switch with direct calls depending on the number of
implementing types. This hopefully makes some interface patterns
zero-cost.
These changes lead to a ~0.5K reduction in code size on Cortex-M for
testdata/interface.go. It appears that a major cause for this is the
replacement of function pointers with direct calls, which are far more
susceptible to optimization. Also, not having a fixed global array of
function pointers greatly helps dead code elimination.
This change also makes future optimizations easier, like optimizations
on interface value comparisons.
A function on a type that is put in an interface must not be assumed to
not need a context pointer when it isn't directly put in a function
pointer, because the interface call side won't know this and pass an
extra parameter with that extra function pointer.
This is usually not a problem but WebAssembly has strict checks on
function signatures so this resulted in an error when running
src/examples/test/test.go.
time.Sleep now compiles on all systems, so lets use that.
Additionally, do a few improvements in time unit handling for the
scheduler. This should lead to somewhat longer sleep durations without
wrapping (on some platforms).
Some examples got smaller, some got bigger. In particular, code using
the scheduler got bigger and the blinky1 example got smaller (especially
on Arduino: 380 -> 314 bytes).
This should make it much easier (in the future) to use the standard
library when unused functions contain unimplemented features. But more
importantly, it makes later passes better and makes compiling faster by
not having to scan dead code.
Previously, mostly the types from the ssa package were used directly
with the types from analysis.go as an overlay. This commit uses these
types everywhere and renames a few things here and there to make things
clearer.
This is a big combined change. Other changes in this commit:
* Analyze makeinterface and make sure type switches don't include
unnecessary cases.
* Do not include CGo wrapper functions in the analyzer callgraph.
This also avoids some unnecessary type IDs.
* Give all Go named structs a name in LLVM.
* Use such a named struct for compiler-generated task data.
* Use the type and function names defined by the ssa and types
package instead of generating our own.
* Some improvements to function pointers.
* A few other minor improvements.
The one thing lacking here is interface-to-interface assertions.
Ayke van Laethem