LLVM optimization passes handle this better, and it allows Zig to
specify pointer parameter attributes such as readonly, nonnull, noalias,
and alignment.
closes#561
This moves some logic from resolveLlvmFunction to updateFunc and takes
advantage of the iteration we already do that takes into account C ABI
lowering, making LLVM parameter attributes accurate for C ABI functions
as well as our own unspecified calling convention.
Related to #11498.
Generally, the load instruction may need to make a copy of an
isByRef=true value, such as in the case of the following code:
```zig
pub fn swap(comptime T: type, a: *T, b: *T) void {
const tmp = a.*;
a.* = b.*;
b.* = tmp;
}
```
However, it only needs to do so if there are any instructions which can
possibly write to memory. When calling functions with isByRef=true
parameters, the AIR code that is generated looks like loads followed
directly by call.
This allows for a peephole optimization when lowering loads: if the load
instruction operates on an isByRef=true type and dies before any side effects
occur, then we can safely lower the load as a no-op that returns its
operand.
This is one out of three changes I intend to make to address #11498.
However I will put these changes in separate branches and merge them
separately so that we can have three independent points on the perf
charts.
After P-256, here comes P-384, also known as secp384r1.
Like P-256, it is required for TLS, and is the current NIST recommendation for key exchange and signatures, for better or for worse.
Like P-256, all the finite field arithmetic has been computed and verified to be correct by fiat-crypto.
This is one out of three changes I intend to make to address #11498.
However I will put these changes in separate branches and merge them
separately so that we can have three independent points on the perf
charts.
This check for primitives is already handled by the generic logic that
checks if the body ends up being empty. I kept this commit in the git
history in case we ever want that nodePrimitive function again in the
future, it might be useful.
The main purpose of this commit is to prepare to implement support for
callconv(), align(), linksection(), and addrspace() annotations on
generic functions where the provided expression depends on comptime
parameters (making the function generic).
It's a rather involved change, so this commit only makes the necessary
changes to AstGen without regressing any behavior, and a follow-up
commit can finish the task by making the enhancements to Sema.
By my quick estimation, the new encoding for functions is a negligible
improvement - along the lines of 0.005% fewer total ZIR bytes on
average. Still, it's nice that this commit, while adding more
data into ZIR, actually ends up reducing the storage size thanks to a
slightly more sophisticated encoding.
Zir.Inst.ExtendedFunc is renamed to Zir.Inst.FuncFancy to eliminate
confusion about it being an extended instruction (it used to be but is
no longer). The encoding for this instruction is completely reworked.
The encoding for Zir.Inst.Func is also changed slightly - when the
return type body length is 1, then only a Zir.Inst.Ref is provided; not
a full body.
linksection() and addrspace() are now communicated via func_fancy ZIR
instruction rather than as part of the corresponding decl. This allows
their expressions to observe comptime parameters.
As demonstrated by this new test case, stage1's functionality is
incorrect since it does not handle slicing from len..len correctly.
stage2 already has the correct behavior here.
all_mask is a value of type sigset_t, which is defined as an array type
[N]u32. However, all_mask references sigset_t.len, but, the array type
does not have a len field. Fix is to use @typeInfo(sigset_t).Array.len
instead.
This tight coupling causes problems for various targets, requires
hacky "get args" functionality, and bungles relative file system paths,
making invalid assumptions about the zig-cache directory.
In short, these are not unit tests; these should be standalone tests
instead.
Reverts e5d4a694ea7dd251e10d6434c9321b5e0a548d4b
Reverts d976456ef665bf0aba3a83a8e7fccb4a92b2d3b2
Reverts dbbda0f41a7c5e214801925f8447a15193c3c731
Closes#11542
