Mostly on macOS, since Loris showed me a not-great stack trace, and I
spent 8 hours trying to make it better. The dyld shared cache is
designed in a way which makes this really hard to do right, and
documentation is non-existent, but this *seems* to work pretty well.
I'll leave the ruling on whether I did a good job to CI and our users.
Our usage of `ucontext_t` in the standard library was kind of
problematic. We unnecessarily mimiced libc-specific structures, and our
`getcontext` implementation was overkill for our use case of stack
tracing.
This commit introduces a new namespace, `std.debug.cpu_context`, which
contains "context" types for various architectures (currently x86,
x86_64, ARM, and AARCH64) containing the general-purpose CPU registers;
the ones needed in practice for stack unwinding. Each implementation has
a function `current` which populates the structure using inline
assembly. The structure is user-overrideable, though that should only be
necessary if the standard library does not have an implementation for
the *architecture*: that is to say, none of this is OS-dependent.
Of course, in POSIX signal handlers, we get a `ucontext_t` from the
kernel. The function `std.debug.cpu_context.fromPosixSignalContext`
converts this to a `std.debug.cpu_context.Native` with a big ol' target
switch.
This functionality is not exposed from `std.c` or `std.posix`, and
neither are `ucontext_t`, `mcontext_t`, or `getcontext`. The rationale
is that these types and functions do not conform to a specific ABI, and
in fact tend to get updated over time based on CPU features and
extensions; in addition, different libcs use different structures which
are "partially compatible" with the kernel structure. Overall, it's a
mess, but all we need is the kernel context, so we can just define a
kernel-compatible structure as long as we don't claim C compatibility by
putting it in `std.c` or `std.posix`.
This change resulted in a few nice `std.debug` simplifications, but
nothing too noteworthy. However, the main benefit of this change is that
DWARF unwinding---sometimes necessary for collecting stack traces
reliably---now requires far less target-specific integration.
Also fix a bug I noticed in `PageAllocator` (I found this due to a bug
in my distro's QEMU distribution; thanks, broken QEMU patch!) and I
think a couple of minor bugs in `std.debug`.
Resolves: #23801Resolves: #23802
Because these lists are very long in several cases and quite
varied, I opted to place them in the existing c/foo.zig files.
There are many other sets of network-related constants like this
to add over time across all the OSes. For now I picked these
because I needed a few constants from each of these namespaces for
my own project, so I tried to flesh out these namespaces
completely as best I could, at least for basic sockopt purposes.
Note windows has some of these already defined in ws2_32 as
individual constants rather than contained in a namespacing
struct. I'm not sure what to do with that in the long run (break
it and namespace them?), but this doesn't change the status quo
for windows in any case.
This mainly just moves stuff around.
Justifications for other changes:
* `KEVENT.FLAGS` is backed by `c_uint` because that's what the `kevent64` flags param takes (according to the 'latest' manpage from 2008)
* `MACH_RCV_NOTIFY` is a legacy name and `MACH_RCV_OVERWRITE` is deprecated (xnu/osfmk/mach/message.h), so I removed them. They were 0 anyway and thus couldn't be represented
as a packed struct field.
* `MACH.RCV` and `MACH.SEND` are technically the same 'type' because they can both be supplied at the same time to `mach_msg`. I decided to still keep them separate because
naming works out better that way and all flags except for `MACH_MSG_STRICT_REPLY` aren't shared anyway. Both are part of a packed union `mach_msg_option_t` which supplies a
helper function to combine the two types.
* `PT` is backed by `c_int` because that's what `ptrace` takes as a request arg (according to the latest manpage from 2015)
* c.darwin: define MSG for macos
* darwin: add series os name
* Update lib/std/c.zig
Co-authored-by: Alex Rønne Petersen <alex@alexrp.com>
---------
Co-authored-by: Alex Rønne Petersen <alex@alexrp.com>
Export the sigset_t ops (sigaddset, etc) from the C library. Don't rely
on the linux.zig defintions (which will be defined to use the kernel ABI).
Move Darwin sigset and NSIG declarations into darwin.zig. Remove
extraneous (?) sigaddset. The C library sigaddset can reject some signals
being added, so need to defer to it.
Functions like isMinGW() and isGnuLibC() have a good reason to exist: They look
at multiple components of the target. But functions like isWasm(), isDarwin(),
isGnu(), etc only exist to save 4-8 characters. I don't think this is a good
enough reason to keep them, especially given that:
* It's not immediately obvious to a reader whether target.isDarwin() means the
same thing as target.os.tag.isDarwin() precisely because isMinGW() and similar
functions *do* look at multiple components.
* It's not clear where we would draw the line. The logical conclusion before
this commit would be to also wrap Arch.isX86(), Os.Tag.isSolarish(),
Abi.isOpenHarmony(), etc... this obviously quickly gets out of hand.
* It's nice to just have a single correct way of doing something.
Turns out this was already fixed in #21964.
I have no idea why GitHub showed an incorrect diff in #21273, or how applying the diff to master was even possible, but here we are.
This was done by regex substitution with `sed`. I then manually went
over the entire diff and fixed any incorrect changes.
This diff also changes a lot of `callconv(.C)` to `callconv(.c)`, since
my regex happened to also trigger here. I opted to leave these changes
in, since they *are* a correct migration, even if they're not the one I
was trying to do!
The compiler actually doesn't need any functional changes for this: Sema
does reification based on the tag indices of `std.builtin.Type` already!
So, no zig1.wasm update is necessary.
This change is necessary to disallow name clashes between fields and
decls on a type, which is a prerequisite of #9938.
* std.c.darwin: add missing CPUFAMILY fields
* std.zig.system.detectNativeCpuAndFeatures: add missing darwin fields
* add comment so the prong isnt lost and easily discoverable during next llvm upgrade
It is now composed of these main sections:
* Declarations that are shared among all operating systems.
* Declarations that have the same name, but different type signatures
depending on the operating system. Often multiple operating systems
share the same type signatures however.
* Declarations that are specific to a single operating system.
- These are imported one per line so you can see where they come from,
protected by a comptime block to prevent accessing the wrong one.
Closes#19352 by changing the convention to making types `void` and
functions `{}`, so that it becomes possible to update `@hasDecl` sites
to use `@TypeOf(f) != void` or `T != void`. Happily, this ended up
removing some duplicate logic and update some bitrotted feature
detection checks.
A handful of types have been modified to gain namespacing and type
safety. This is a breaking change.
Oh, and the last usage of `usingnamespace` site is eliminated.
I believe this was accidentally broken when the E enum for errno values
was introduces. These functions are quite the special case in that they
return the error value directly rather than returning -1 and passing the
error value through the errno variable.
In any case, using a u16 as the return type at the ABI boundary where a
c_int is expected is asking for trouble.
A pointer type already has an alignment, so this information does not
need to be duplicated on the function type. This already has precedence
with addrspace which is already disallowed on function types for this
reason. Also fixes `@TypeOf(&func)` to have the correct addrspace and
alignment.
* std.c: consolidate some definitions, making them share code. For
example, freebsd, dragonfly, and openbsd can all share the same
`pthread_mutex_t` definition.
* add type safety to std.c.O
- this caught a bug where mode flags were incorrectly passed as the
open flags.
* 3 fewer uses of usingnamespace keyword
* as per convention, remove purposeless field prefixes from struct field
names even if they have those prefixes in the corresponding C code.
* fix incorrect wasi libc Stat definition
* remove C definitions from incorrectly being in std.os.wasi
* make std.os.wasi definitions type safe
* go through wasi native APIs even when linking libc because the libc
APIs are problematic and wasteful
* don't expose WASI definitions in std.posix
* remove std.os.wasi.rights_t.ALL: this is a footgun. should it be all
future rights too? or only all current rights known? both are
the wrong answer.
