Set -resource-dir in a central place instead of passing the header path
around everywhere and adding it using the `-I` flag. I believe this is
closer to how Clang is intended to be used.
This change was inspired by my attempt to add a Nix flake file to
TinyGo.
This fixes https://github.com/tinygo-org/tinygo/issues/3926.
While working on this I've found another bug: if C.bool is referenced
from within Go, it isn't available anymore on the C side. This is an
existing bug that also applies to float and double, but may be less
likely to be triggered there.
This bug is something to be fixed at a later time (it has something to
do with preprocessor defines).
They are not necessary in TinyGo because they always map to float32 and
float64, but it's a good idea to add them regardless for compatibility
with existing software.
(Now I think about it, perhaps it would have been better to require
explicit casts here just in case we want to support some really weird C
system, but then again we even force 64-bit double on AVR even though
avr-gcc defaults to 32-bit double).
* cgo: fixes panic when FuncType.Results is nil
FuncType.Results can be nil. This fixes the comparison and backfills
relevant tests.
Signed-off-by: Adrian Cole <adrian@tetrate.io>
Co-authored-by: Ayke <aykevanlaethem@gmail.com>
Go 1.19 started reformatting code in a way that makes it more obvious
how it will be rendered on pkg.go.dev. It gets it almost right, but not
entirely. Therefore, I had to modify some of the comments so that they
are formatted correctly.
This is a large refactor of the cgo package. It should fix a number of
smaller problems and be a bit more strict (like upstream CGo): it for
example requires every Go file in a package to include the header files
it needs instead of piggybacking on imports in earlier files.
The main benefit is that it should be a bit more maintainable and easier
to add new features in the future (like static functions).
This breaks the tinygo.org/x/bluetooth package, which should be updated
before this change lands.
It should only be added at the point that it is needed, for example when
using libclang or using the built-in Clang. It isn't needed when running
an external tool.
Instead of storing an increasing version number in relevant packages
(compiler.Version, interp.Version, cgo.Version, ...), read the build ID
from the currently running executable. This has several benefits:
* All changes relevant to the compiled packages are caught.
* No need to bump the version for each change to these packages.
This avoids merge conflicts.
* During development, `go install` is enough. No need to run
`tinygo clean` all the time.
Of course, the drawback is that it might be updated a bit more often
than necessary but I think the overall benefit is big.
Regular release users shouldn't see any difference. Because the tinygo
binary stays the same, the cache works well.
This patch adds //go: pragmas directly to declared functions and
globals found during CGo processing. This simplifies the logic in the
compiler: it no longer has to consider special "C." prefixed function
names. It also makes the cgo pass more flexible in the pragmas it emits
for functions and global variables.
Previously, libclang was run on each fragment (import "C") separately.
However, in regular Go it's possible for later fragments to refer to
types in earlier fragments so they must have been parsed as one.
This commit changes the behavior to run only one C parser invocation for
each Go file.
For example, the following did not work before but does work with this
change:
// int add(int a, int b) {
// return a + b;
// }
import "C"
func main() {
println("add:", C.add(3, 5))
}
Even better, the functions in the header are compiled together with the
rest of the Go code and so they can be optimized together! Currently,
inlining is not yet allowed but const-propagation across functions
works. This should be improved in the future.
This is a loose collection of small fixes flagged by staticcheck:
- dead code
- regexp expressions not using backticks (`foobar` / "foobar")
- redundant types of slice and map initializers
- misc other fixes
Not all of these seem very useful to me, but in particular dead code is
nice to fix. I've fixed them all just so that if there are problems,
they aren't hidden in the noise of less useful issues.
This patch adds support for passing CFLAGS added in #cgo lines of the
CGo preprocessing phase to the compiler when compiling C files inside
packages. This is expected and convenient but didn't work before.
This commit switches from the previous behavior of compiling the whole
program at once, to compiling every package in parallel and linking the
LLVM bitcode files together for further whole-program optimization.
This is a small performance win, but it has several advantages in the
future:
- There are many more things that can be done per package in parallel,
avoiding the bottleneck at the end of the compiler phase. This
should speed up the compiler futher.
- This change is a necessary step towards a non-LTO build mode for
fast incremental builds that only rebuild the changed package, when
compiler speed is more important than binary size.
- This change refactors the compiler in such a way that it will be
easier to inspect the IR for one package only. Inspecting this IR
will be very helpful for compiler developers.
This doesn't yet add support for actually making use of variadic
functions, but at least allows (unintended) variadic functions like the
following to work:
void foo();
This is necessary for better CGo support on bare metal. Existing
libraries expect to be able to include parts of libc and expect to be
able to link to those symbols.
Because with this all targets have a working libc, it is now possible to
add tests to check that a libc in fact works basically.
Not all parts of picolibc are included, such as the math or stdio parts.
These should be added later, when needed.
This commit also avoids the need for the custom memcpy/memset/memcmp
symbols that are sometimes emitted by LLVM. The C library will take care
of that.
This implementation is still very limited but provides a base to build
upon. Limitations:
* CGO_CFLAGS etc is not taken into account.
* These CFLAGS are not used in C files compiled with the package.
* Other flags (CPPFLAGS, LDFAGS, ...) are not yet implemented.
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.
This commit renames reserved field names like `type` to `_type`, and in
turn renames those fields as well (recursively). This avoids name
clashes when a C struct contains a field named `type`, which is a
reserved keyword in Go.
For some details, see:
https://golang.org/cmd/cgo/#hdr-Go_references_to_C
Previously it was just a combination of heuristics to try to fit a
constant in an *ast.BasicLit. For more complex expressions, this is not
enough.
This change also introduces proper syntax error with locations, if
parsing a constant failed. For example, this will print a real error
message with source location:
#define FOO 5)
Previously, a GenDecl was shared between many different
consts/vars/types. However, it actually makes much more sense not to
bundle them as that is also the case in C.
This makes the printed output of the CGo AST much nicer, and works
around a bug in Go 1.11.
This commit improves diagnostics in a few ways:
* All panics apart from panics with no (easy) recovery are converted to
regular errors with source location.
* Some errors were improved slightly to give more information. For
example, show the libclang type kind as a string instead of a
number.
* Improve source location by respecting line directives in the C
preprocessor.
* Refactor to unify error handling between libclang diagnostics and
failures to parse the libclang AST.
Enum types are implemented as named types (with possible accompanying
typedefs as type aliases). The constants inside the enums are treated as
Go constants like in the Go toolchain.
This is a big commit that does a few things:
* It moves CGo processing into a separate package. It never really
belonged in the loader package, and certainly not now that the
loader package may be refactored into a driver package.
* It adds support for multiple CGo files (files that import package
"C") in a single package. Previously, this led to multiple
definition errors in the Go typecheck phase because certain C
symbols were defined multiple times in all the files. Now it
generates a new fake AST that defines these, to avoid multiple
definition errors.
* It improves debug info in a few edge cases that are probably not
relevant outside of bugs in cgo itself.
Only try to convert the C symbols to their Go equivalents that are
actually referenced by the Go code with C.<somesymbol>. This avoids
having to support all possible C types, which is difficult because of
oddities like `typedef void` or `__builtin_va_list`. Especially
__builtin_va_list, which varies between targets.
Every ABI has a slightly different implementation. Ideally, we would use
something like Clang TargetInfo or extract it by compiling some C code
and checking the IR, but this is a useful workaround for now.
These types (called elaborated types in C) are used as part of linked
lists, among others.
This is part an extra feature (to be compatible with CGo C.struct_
types) and part a bugfix: linked lists would result in endless recursion
leading to a stack overflow.
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
Ayke van Laethem
Crypt Keeper
Lucas Teske
Justin Clift