This has the benefit of not requiring a 'runtime' IR file, so that
complete relocatable files can be built without requiring input IR.
This makes the compiler a lot easier to use without the Makefile.
Code size is not affected.
Comparing an interface to nil is easy, as the dynamic type is also nil.
Comparing the dynamic values (when the dynamic types match) is much
harder and depends on reflection capabilities, so is not yet implemented.
TODO: do better at it by tracking min/max values of integers. The
following straightforward code doesn't have its bounds checks removed:
for _, n := range slice {
println(n)
}
I've tried writing my own, but I couldn't make it correct in all cases.
So just copy the one from upstream for now, hopefully to be replaced at
some point.
TODO: add a printfloat32() implementation, now it just casts to float64.
This will be useful for embedded systems that sometimes have float32 but
not float64.
CGo depends on syscall, which (in the standard library) depends on sync,
which depends on the runtime. There are also other import cycles. To be
able to use the syscall package from upstream, stop using CGo.
It took Android some time to even hit the 64K limit for regular method
calls, so switching to 16-bit IDs should be fine for method IDs of
interfaces. At least for the time being. When this limit is ever hit,
I'll think of another way, probably involving some platform-dependent
interface code (e.g. microcontrollers won't need 64K of methods) or
detecting the limit at build time.
https://android-developers.googleblog.com/2014/12/google-play-services-and-dex-method.html
Code size isn't changed, probably because the compiler optimizes away
all method calls.
This commit moves the itfmethod call implemented directly in LLVM IR to
a Go implementation in the runtime. Additionally, it fixes variable
names to be more obvious and adds a lot of documentation to explain how
interfaces actually work in TinyGo.
Code size changes for src/examples/hello:
nrf: -144
unix: -93
I'm guessing this code size reduction is a result of removing the
'noinline' function attribute.
This massively increases .data size, possibly because loads of unused
globals are included. I'll need to investigate what's going on here. For
now, increase the RAM size for nrf chips (the nrf52 has 64kB of RAM).
Missing features:
* keys other than strings
* more than 8 values in the hashmap
* growing a map when needed
* initial size hint
* delete(m, key)
* iterators (for range)
* initializing global maps
* ...more?
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.
This requires support in LLVM, as AVR support is still experimental. For
example, in bindings/go/build.sh, add
-DLLVM_EXPERIMENTAL_TARGETS_TO_BUILD=AVR to cmake_flags.
