The ar file format is pretty simple and can be implemented by using a Go
library. Use that instead of calling out to llvm-ar.
There are a few limitations to the used package, but that doesn't seem
to matter for our use case (linking compiler-rt for use with ld.lld):
* no index is created
* long filenames are truncated
* no support for archives bigger than 4GB
This makes CGo-emitted diagnostics very similar to regular errors
emitted while parsing/typechecking a package.
It's not complete, but after introducing some errors in testdata/cgo,
this is the resulting output:
# ./testdata/cgo/
testdata/cgo/main.h:18:11: error: a parameter list without types is only allowed in a function definition
testdata/cgo/main.go:5:10: note: in file included from testdata/cgo/main.go!cgo.c:2:
testdata/cgo/main.go:6:19: error: expected identifier or '('
Previously, this was the output:
/home/ayke/src/github.com/tinygo-org/tinygo/testdata/cgo/main.h:18:11: error: a parameter list without types is only allowed in a function definition
cgo-fake.c:3:19: error: expected identifier or '('
# ./testdata/cgo/
cgo: libclang cannot parse fragment
This pattern is often used in some runtime intrinsics (especially the
ones related to slices) to do pointer arithmetic with unsafe.Pointer and
uintptr because Go does not support pointer arithmetic.
Recognizing this pattern and replacing it with a gep instruction
improves code size in various tests.
Add nocapture, readonly, and writeonly to runtime.memmove and
runtime.memcpy where appropriate. This teaches LLVM some more
optimizations it may perform, leading to reduced .text size in some
cases.
Previously, when casting an integer to a bigger integer, the destination
signedness was used. This is problematic when casting a negative int16
to uint32, for example, because it would cause zero-extension.
This didn't trigger on most platforms but does trigger on AVR where
almost all slice operations on strings are with integers that are bigger
than uintptr.
A call to .IsConstant() also returns true for constant globals, not just
constant expressions. Do an extra check that we're really operating on a
constant expression.
This provides several advantages. Among others:
* Much faster and hopefully more reliable.
* Good caching support to store LLVM builds.
* Building and testing of release-ready artifacts.
Go 1.12 switched to using libSystem.dylib for system calls, because
Apple recommends against doing direct system calls that Go 1.11 and
earlier did. For more information, see:
https://github.com/golang/go/issues/17490https://developer.apple.com/library/archive/qa/qa1118/_index.html
While the old syscall package was relatively easy to support in TinyGo
(just implement syscall.Syscall*), this got a whole lot harder with Go
1.12 as all syscalls now go through CGo magic to call the underlying
libSystem functions. Therefore, this commit overrides the stdlib syscall
package with a custom package that performs calls with libc (libSystem).
This may be useful not just for darwin but for other platforms as well
that do not place the stable ABI at the syscall boundary like Linux but
at the libc boundary.
Only a very minimal part of the syscall package has been implemented, to
get the tests to pass. More calls can easily be added in the future.
LLD version 8 has added support for armv6m:
https://reviews.llvm.org/D55555
This means we can use LLD instead of arm-none-eabi-ld, eliminating our
dependency on GNU binutils.
There are small differences in code size, but never more than a few
bytes.
This commit does a few things:
* remove the -8 suffix on macOS, where it is not necessary
* add smoke tests for compiling wasm files on Linux and macOS
The icmp instruction is often used in nil checks, so this instruction
happens very frequently now that TinyGo automatically inserts nil checks
everywhere. Escape analysis would conservatively mark such pointers as
escaping, which they obviously don't.
This commit improves escape analysis to allow icmp instructions.
So far, we've pretended to be js/wasm in baremetal targets to make the
stdlib happy. Unfortunately, this has various problems because
syscall/js (a dependency of many stdlib packages) thinks it can do JS
calls, and emulating them gets quite hard with all changes to the
syscall/js packages in Go 1.12.
This commit does a few things:
* It lets baremetal targets pretend to be linux/arm instead of
js/wasm.
* It lets the loader only select particular packages from the src
overlay, instead of inserting them just before GOROOT. This makes it
possible to pick which packages to overlay for a given target.
* It adds a baremetal-only syscall package that stubs out almost all
syscalls.
Implement two trivial uses of the select statement.
Always blocking:
select {}
No-op:
select {
default:
}
Go 1.12 added a `select {}` instruction to syscall/js, so this is needed
for Go 1.12 support. More complete support for select will be added in
the future.
This function returns the current timestamp, or 0 at compile time.
runtime.nanotime is used at package initialization by the time package
starting with Go 1.12.
The function extracting the firmware image for .hex and .bin files
wasn't working correctly: it only extracted the .text segment and not
the .data segment.
This commit fixes this issue, so that it behaves (hopefully) just like
objcopy -O{ihex|binary}.
Another small change is that the formatting of the .hex file was made
more like the output of objcopy: no entry addres (old Intel CPU
holdover) and 16 bytes of data on each line.
Move these asserts into compiler/asserts.go, to keep them together.
The make([]T) asserts aren't moved yet because that code is (still!)
quite ugly and in need of some clean up.
This commit implements nil checks for all platforms. These nil checks
can be optimized on systems with a MMU, but since a major target is
systems without MMU, keep it this way for now.
It implements three checks:
* Nil checks before dereferencing a pointer.
* Nil checks before calculating an address (*ssa.FieldAddr and
*ssa.IndexAddr)
* Nil checks before calling a function pointer.
The first check has by far the biggest impact, with around 5% increase
in code size. The other checks only trigger in only some test cases and
have a minimal impact on code size.
This first nil check is also the one that is easiest to avoid on systems
with MMU, if necessary.
Whenever interp hits an unreachable instruction, it bails out at that
point. However, it used to insert new instructions at the bottom with
the old init calls still at the top. So when a panic() happened in a
non-main package, the last packages to init would actually be called
first.
This commit fixes this by setting the insert point at the top of
runtime.initAll before starting interpretation, so the initialization
order is still correct when a panic() happens during init.
The wasm_exec.js file copied from the main Go repository did write those
values to address 4096 in linear memory, which led to memory corruption
in linear memory. Remove these things for now, until they're actually
supported, if support is ever added.
The WebAssembly target is not yet considered stable in LLVM 7, but has
been enabled in the Debian builds so tests can run on Debian. However,
the Homebrew builds don't have it enabled which results in test
failures.
Temporarily run WebAssembly tests only on Linux to fix this. This can be
reverted after a switch to LLVM 8, which has WebAssembly enabled by
default.
In LLVM 8, the AVR backend has moved all function pointers to address
space 1 by default. Much of the code still assumes function pointers
live in address space 0, leading to assertion failures.
This commit fixes this problem by autodetecting function pointers and
avoiding them in interface pseudo-calls.
Without this, the following code would not panic:
func getInt(i int) { return i }
make([][1<<18], getInt(1<<18))
Or this code would be allowed to compile for 32-bit systems:
make([][1<<18], 1<<18)
