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codegen: use new {re,de,}allocator annotations in llvm

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This obviates the patch that teaches LLVM internals about
_rust_{re,de}alloc functions by putting annotations directly in the IR
for the optimizer.

The sole test change is required to anchor FileCheck to the body of the
`box_uninitialized` method, so it doesn't see the `allocalign` on
`__rust_alloc` and get mad about the string `alloca` showing up. Since I
was there anyway, I added some checks on the attributes to prove the
right attributes got set.

While we're here, we also emit allocator attributes on
__rust_alloc_zeroed. This should allow LLVM to perform more
optimizations for zeroed blocks, and probably fixes #90032. [This
comment](https://github.com/rust-lang/rust/issues/24194#issuecomment-308791157)
mentions "weird UB-like behaviour with bitvec iterators in
rustc_data_structures" so we may need to back this change out if things
go wrong.

The new test cases require LLVM 15, so we copy them into LLVM
14-supporting versions, which we can delete when we drop LLVM 14.
This commit is contained in:
Augie Fackler 2022-03-21 15:30:54 -04:00
parent 2fdbf075cf
commit 130a1df71e
14 changed files with 356 additions and 4 deletions
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144
src/test/codegen/vec-calloc-llvm14.rs Normal file
View file

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// compile-flags: -O
// only-x86_64
// ignore-debug
#![crate_type = "lib"]
// CHECK-LABEL: @vec_zero_bytes
#[no_mangle]
pub fn vec_zero_bytes(n: usize) -> Vec<u8> {
// CHECK-NOT: call {{.*}}alloc::vec::from_elem
// CHECK-NOT: call {{.*}}reserve
// CHECK-NOT: call {{.*}}__rust_alloc(
// CHECK-NOT: call {{.*}}llvm.memset
// CHECK: call {{.*}}__rust_alloc_zeroed(
// CHECK-NOT: call {{.*}}alloc::vec::from_elem
// CHECK-NOT: call {{.*}}reserve
// CHECK-NOT: call {{.*}}__rust_alloc(
// CHECK-NOT: call {{.*}}llvm.memset
// CHECK: ret void
vec![0; n]
}
// CHECK-LABEL: @vec_one_bytes
#[no_mangle]
pub fn vec_one_bytes(n: usize) -> Vec<u8> {
// CHECK-NOT: call {{.*}}alloc::vec::from_elem
// CHECK-NOT: call {{.*}}reserve
// CHECK-NOT: call {{.*}}__rust_alloc_zeroed(
// CHECK: call {{.*}}__rust_alloc(
// CHECK: call {{.*}}llvm.memset
// CHECK-NOT: call {{.*}}alloc::vec::from_elem
// CHECK-NOT: call {{.*}}reserve
// CHECK-NOT: call {{.*}}__rust_alloc_zeroed(
// CHECK: ret void
vec![1; n]
}
// CHECK-LABEL: @vec_zero_scalar
#[no_mangle]
pub fn vec_zero_scalar(n: usize) -> Vec<i32> {
// CHECK-NOT: call {{.*}}alloc::vec::from_elem
// CHECK-NOT: call {{.*}}reserve
// CHECK-NOT: call {{.*}}__rust_alloc(
// CHECK: call {{.*}}__rust_alloc_zeroed(
// CHECK-NOT: call {{.*}}alloc::vec::from_elem
// CHECK-NOT: call {{.*}}reserve
// CHECK-NOT: call {{.*}}__rust_alloc(
// CHECK: ret void
vec![0; n]
}
// CHECK-LABEL: @vec_one_scalar
#[no_mangle]
pub fn vec_one_scalar(n: usize) -> Vec<i32> {
// CHECK-NOT: call {{.*}}alloc::vec::from_elem
// CHECK-NOT: call {{.*}}reserve
// CHECK-NOT: call {{.*}}__rust_alloc_zeroed(
// CHECK: call {{.*}}__rust_alloc(
// CHECK-NOT: call {{.*}}alloc::vec::from_elem
// CHECK-NOT: call {{.*}}reserve
// CHECK-NOT: call {{.*}}__rust_alloc_zeroed(
// CHECK: ret void
vec![1; n]
}
// CHECK-LABEL: @vec_zero_rgb48
#[no_mangle]
pub fn vec_zero_rgb48(n: usize) -> Vec<[u16; 3]> {
// CHECK-NOT: call {{.*}}alloc::vec::from_elem
// CHECK-NOT: call {{.*}}reserve
// CHECK-NOT: call {{.*}}__rust_alloc(
// CHECK: call {{.*}}__rust_alloc_zeroed(
// CHECK-NOT: call {{.*}}alloc::vec::from_elem
// CHECK-NOT: call {{.*}}reserve
// CHECK-NOT: call {{.*}}__rust_alloc(
// CHECK: ret void
vec![[0, 0, 0]; n]
}
// CHECK-LABEL: @vec_zero_array_16
#[no_mangle]
pub fn vec_zero_array_16(n: usize) -> Vec<[i64; 16]> {
// CHECK-NOT: call {{.*}}alloc::vec::from_elem
// CHECK-NOT: call {{.*}}reserve
// CHECK-NOT: call {{.*}}__rust_alloc(
// CHECK: call {{.*}}__rust_alloc_zeroed(
// CHECK-NOT: call {{.*}}alloc::vec::from_elem
// CHECK-NOT: call {{.*}}reserve
// CHECK-NOT: call {{.*}}__rust_alloc(
// CHECK: ret void
vec![[0_i64; 16]; n]
}
// CHECK-LABEL: @vec_zero_tuple
#[no_mangle]
pub fn vec_zero_tuple(n: usize) -> Vec<(i16, u8, char)> {
// CHECK-NOT: call {{.*}}alloc::vec::from_elem
// CHECK-NOT: call {{.*}}reserve
// CHECK-NOT: call {{.*}}__rust_alloc(
// CHECK: call {{.*}}__rust_alloc_zeroed(
// CHECK-NOT: call {{.*}}alloc::vec::from_elem
// CHECK-NOT: call {{.*}}reserve
// CHECK-NOT: call {{.*}}__rust_alloc(
// CHECK: ret void
vec![(0, 0, '\0'); n]
}
// CHECK-LABEL: @vec_non_zero_tuple
#[no_mangle]
pub fn vec_non_zero_tuple(n: usize) -> Vec<(i16, u8, char)> {
// CHECK-NOT: call {{.*}}alloc::vec::from_elem
// CHECK-NOT: call {{.*}}reserve
// CHECK-NOT: call {{.*}}__rust_alloc_zeroed(
// CHECK: call {{.*}}__rust_alloc(
// CHECK-NOT: call {{.*}}alloc::vec::from_elem
// CHECK-NOT: call {{.*}}reserve
// CHECK-NOT: call {{.*}}__rust_alloc_zeroed(
// CHECK: ret void
vec![(0, 0, 'A'); n]
}