Emilio Cobos Álvarez
5ac196d3ef
I want this to move around slices and boxes across the style system, while preserving the option size optimizations when they're fully in a repr(Rust) data-structure. This is sound because NonNull is repr(transparent): https://doc.rust-lang.org/src/core/ptr.rs.html#2847 I renamed simplify_option_to_ptr to simplify_standard_types because that's what it does now. ABI-wise for NonNull<T> it's guaranteed via repr(transparent). For Option<NonNull<T>> it is as well, though I've asked in #rustc to confirm. The LLVM IR of: ``` pub extern "C" fn foo(ptr: Option<::std::ptr::NonNull<i32>>) {} ``` is: ``` define void @foo(i32*) unnamed_addr #0 !dbg !310 { start: %ptr = alloca i32*, align 8 store i32* %0, i32** %ptr, align 8 call void @llvm.dbg.declare(metadata i32** %ptr, metadata !327, metadata !DIExpression()), !dbg !328 ret void, !dbg !329 } ``` Which is the same as for: ``` pub extern "C" fn foo(ptr: ::std::ptr::NonNull<i32>) {} ``` Except without the nonnull annotation. And the same as for: ``` pub extern "C" fn foo(ptr: *mut i32) {} ```
24 lines
287 B
C++
24 lines
287 B
C++
#include <cstdint>
|
|
#include <cstdlib>
|
|
|
|
struct Opaque;
|
|
|
|
template<typename T>
|
|
struct Foo {
|
|
float *a;
|
|
T *b;
|
|
Opaque *c;
|
|
T **d;
|
|
float **e;
|
|
Opaque **f;
|
|
T *g;
|
|
int32_t *h;
|
|
int32_t **i;
|
|
};
|
|
|
|
extern "C" {
|
|
|
|
void root(int32_t *arg, Foo<uint64_t> *foo, Opaque **d);
|
|
|
|
} // extern "C"
|