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.
This mostly works around the default CGo support: this compiler doesn't
need special wrappers for C functions as it uses the C calling
convention by default.
