This makes the following changes for i386:
long long and unsigned long long have 4 byte alignment on non-Windows
f64 (double) has 4-byte alignment on non-Windows
long double is 80 bits and has 4 byte alignment on mingw
long double on android is 64 bits, not 80: https://www.uclibc.org/docs/psABI-i386.pdfFixes#12453Fixes#12987
This implements `@export(a.b, .{..});` in semantic analysis,
allowing users to directly export a variable from a namespace.
* add test case for exporting using field access
Without the packed qualifier, the type layout that we use to
initialize doesn't match the correct layout of the underlying
storage, causing corrupted data and past-the-end writes.
When testing the Wasm linker for the producers section
we do not ever want to strip the binary as this will remove
the producers section in release-small.
This fixes the CI errors by d086b371f0
These tests will be failing on many platforms until #8465 is resolved.
Luckily, the particular function signature used for __divXc3 and __mulXc3
seems to be OK on x86-64.
These are the standard complex multiplication/division functions
required by the C standard (Annex G).
Don't get me started on the standard's handling of complex-infinity...
This also turns off non-debug modes for the bss linker tests for
Wasm. This is done as it's not required to guarantee to zero out
the bss section for non-debug modes.
expected type 'fn() void', found 'fn(i32) void'
function with 0 parameters cannot cast into a function with 0 parameters
=>
expected type 'fn() void', found 'fn(i32) void'
function with 1 parameters cannot cast into a function with 0 parameters
Superceeds PR #12735 (now supporting all packed structs in GNU C)
Fixes issue #12733
This stops translating C packed struct as a Zig packed struct.
Instead use a regular `extern struct` with `align(1)`.
This is because (as @Vexu explained) Zig packed structs are really just integers (not structs).
Alignment issue is more complicated. I think @ifreund was the
first to notice it in his comment on PR #12735
Justification of my interpretion of the C(lang) behavior
comes from a careful reading of the GCC docs for type & variable attributes:
(clang emulates gnu's packed attribute here)
The final line of the documentation for __attribute__ ((aligned)) [on types] says:
> When used on a struct, or struct member, *the aligned attribute can only increase the alignment*; in order to decrease it, the packed attribute must be specified as well.
This implies that GCC uses the `packed` attribute for alignment purposes
in addition to eliminating padding.
The documentation for __attribute__((packed)) [on types], states:
> This attribute, attached to a struct, union, or C++ class type definition, specifies that each of its members (other than zero-width bit-fields) is placed to minimize the memory required. **This is equivalent to specifying the packed attribute on each of the members**.
The key is resolving this indirection, and looking at the documentation
for __attribute__((packed)) [on fields (wierdly under "variables" section)]:
> The packed attribute specifies that a **structure member should have the smallest possible alignment** — one bit for a bit-field and one byte otherwise, unless a larger value is specified with the aligned attribute. The attribute does not apply to non-member objects.
Furthermore, alignment is the only effect of the packed attribute mentioned in the GCC docs (for "common" architecture).
Based on this, it seems safe to completely substitute C 'packed' with Zig 'align(1)'.
Target-specific or undocumented behavior potentially changes this.
Unfortunately, the current implementation of `translate-c` translates as
`packed struct` without alignment info.
Because Zig packed structs are really integers (as mentioned above),
they are the wrong interpretation and we should be using 'extern struct'.
Running `translate-c` on the following code:
```c
struct foo {
char a;
int b;
} __attribute__((packed));
struct bar {
char a;
int b;
short c;
__attribute__((aligned(8))) long d;
} __attribute__((packed));
```
Previously used a 'packed struct' (which was not FFI-safe on stage1).
After applying this change, the translated structures have align(1)
explicitly applied to all of their fields AS EXPECTED (unless explicitly overriden).
This makes Zig behavior for `tranlsate-c` consistent with clang/GCC.
Here is the newly produced (correct) output for the above example:
```zig
pub const struct_foo = extern struct {
a: u8 align(1),
b: c_int align(1),
};
pub const struct_bar = extern struct {
a: u8 align(1),
b: c_int align(1),
c: c_short align(1),
d: c_long align(8),
};
```
Also note for reference: Since the last stable release (0.9.1),
there was a change in the language spec
related to the alignment of packed structures.
The docs for Zig 0.9.1 read:
> Packed structs have 1-byte alignment.
So the old behavior of translate-c (not specifying any alignment) was possibly correct back then.
However the current docs read:
> Packed structs have the same alignment as their backing integer
Suggsestive both to the change to an integer-backed representation
which is incompatible with C's notation.
When encountering a fn type that returns an error (union), a backend
that supports error return tracing will want the StackTrace struct and
its fields to be analyzed.
* the root struct decl name is fully qualified
this prevents error messages containing 'main.main'
* avoid declared here note when file struct is missing a member
It always points at the start of the file which might contain another
container misleading the user.
