For calling convention ABI purposes, integer attributes and return
values need to have an LLVM attribute signext or zeroext added
sometimes. This commit implements that logic.
It also implements a proof-of-concept of moving the F16T type from
being a compiler_rt hack to being how the compiler lowers f16 in
functions that need to match certain calling conventions.
Closes#12054
For some targets, Clang unconditionally adds some clobbers to all inline assembly.
While this is probably not strictly necessary, if we don't follow Clang's lead
here then we may risk tripping LLVM bugs since anything not used by Clang tends
to be buggy and regress often.
LLVM does not properly handle debug info for f16 on the aarch64-windows
target, causing "fatal error: unknown codeview register H1". The
previous workaround checked only for f16 but was still vulnerable if a
type was a byval struct or tuple which had an f16 field in it.
Now I have filed an upstream issue (see
https://github.com/llvm/llvm-project/issues/56484) and broadened the
workaround to always skip debug values for this target.
Our lowerings for various LLVM types assume that we can anticipate the
alignment/layout that LLVM will generate. Among other things, this
requires that we keep the alignment of our lowered LLVM types
synchronized with their expected alignment in Zig.
- Arrays were using packed struct types, which is seems to be
incorrect since array elements are supposed to be self-aligned.
- Unions were using packed struct types for their payload, which causes
layout divergence between what stage2 expects and what LLVM generates
Consider this lowered union type:
```llvm
%Value = type { <{ i64, [8 x i8] }>, i1, [7 x i8] } ; 24 bytes, align(1)
%ErrorUnion = type { %Value, i16 } ; 26 bytes, align(2)
```
Zig expects Value to be align(8) and, by extension, for ErrorUnion to be
size 32.
The previous code here was potentially more optimal for some cases,
however, I never tested the perf, so it might not actually matter. This
code handles more cases. We can go back and re-evaluate that other
implementation if it seems worthwhile in the future.
LLVM 14 makes it so that a RHS of saturating shift left produces a
poison value if the value is greater than the number of bits of the LHS.
Zig now emits code that will check if this is the case and select a
saturated LHS value in such case, matching Zig semantics.
The constant value lowering for unions was missing a check for whether
the payload was itself an unnamed struct. Lowerings of other types
already handle this case.
closes#11971
Rather than lowering float negation as `0.0 - x`.
* Add AIR instruction for float negation.
* Add compiler-rt functions for f128, f80 negation
closes#11853
The LLVM backend was calculating the amount of padding solely based
on the payload size. However, in the case where there is no union
tag, this fails to take into account alignment.
Closes#11857
llvm: dump failed module when -femit-llvm-ir set
print_air:
* print fully qualified name
* use Type.fmt and Value.fmtValue, fmtDebug is useless
TypedValue
* handle anon structs and tuples
* fix bugs
And use it to debug a LazySrcLoc in stage2 that is set to a bogus value.
The actual fix in this commit is:
```diff
- try sema.emitBackwardBranch(&child_block, call_src);
+ try sema.emitBackwardBranch(block, call_src);
```
Zig allows multiple extern functions with the same name, and the
backends have to handle this possibility.
For LLVM, we keep a sparse map of collisions, and then resolve them in
flushModule(). This introduces some technical debt that will have to be
resolved when adding incremental compilation support to the LLVM
backend.
Implements semantic analysis for the new try/try_inline ZIR
instruction. Adds the new try/try_ptr AIR instructions and implements
them for the LLVM backend.
Fixes not calling rvalue() for tryExpr in AstGen.
This is part of an effort to implement #11772.
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.
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.
