Need less bumf to pass Layout to __rustc_alloc

[scottmcm]

Rather than discriminants and casts, how about we just pass the Alignment directly?

r? ghost

[scottmcm]

@bors try @rust-timer queue

[rust-bors]

⌛ Trying commit b954406 with merge 12f11b8…

To cancel the try build, run the command @bors try cancel.

[rust-log-analyzer]

The job x86_64-gnu-miri failed! Check out the build log: (web) (plain enhanced) (plain)

Click to see the possible cause of the failure (guessed by this bot)

tests/pass/shims/x86/intrinsics-x86-avx2.rs ... ok
tests/pass/shims/x86/intrinsics-x86-gfni.rs ... ok

FAILED TEST: tests/pass/global_allocator.rs
command: MIRI_ENV_VAR_TEST="0" MIRI_TEMP="/tmp/miri-uitest-CV8oFV" RUST_BACKTRACE="1" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/miri" "--error-format=json" "--sysroot=/checkout/obj/build/x86_64-unknown-linux-gnu/miri-sysroot" "-Dwarnings" "-Dunused" "-Ainternal_features" "-Zui-testing" "--out-dir" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage1-tools/x86_64-unknown-linux-gnu/tmp/miri_ui/0/tests/pass" "tests/pass/global_allocator.rs" "--edition" "2021"

error: test got exit status: 1, but expected 0
 = note: compilation failed, but was expected to succeed

error: no output was expected
Execute `./miri test --bless` to update `tests/pass/global_allocator.stderr` to the actual output
+++ <stderr output>
error: Undefined Behavior: calling a function whose parameter #2 has type usize passing argument of type std::ptr::Alignment
##[error]  --> tests/pass/global_allocator.rs:32:15
   |
LL |     let ptr = Global.allocate(l).unwrap().as_non_null_ptr(); // allocating with Global...
   |               ^^^^^^^^^^^^^^^^^^ Undefined Behavior occurred here
   |
   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
   = help: this means these two types are not *guaranteed* to be ABI-compatible across all targets
   = help: if you think this code should be accepted anyway, please report an issue with Miri
   = note: BACKTRACE:
   = note: inside `main` at tests/pass/global_allocator.rs:32:15: 32:33

note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace

---
full stderr:
error: Undefined Behavior: calling a function whose parameter #2 has type usize passing argument of type std::ptr::Alignment
##[error]  --> tests/pass/global_allocator.rs:32:15
   |
LL |     let ptr = Global.allocate(l).unwrap().as_non_null_ptr(); // allocating with Global...
   |               ^^^^^^^^^^^^^^^^^^ Undefined Behavior occurred here
   |
   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
   = help: this means these two types are not *guaranteed* to be ABI-compatible across all targets
   = help: if you think this code should be accepted anyway, please report an issue with Miri
   = note: BACKTRACE:
   = note: inside `main` at tests/pass/global_allocator.rs:32:15: 32:33

note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace

---



FAILED TEST: tests/pass/backtrace/backtrace-global-alloc.rs
command: MIRI_ENV_VAR_TEST="0" MIRI_TEMP="/tmp/miri-uitest-CV8oFV" RUST_BACKTRACE="1" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/miri" "--error-format=json" "--sysroot=/checkout/obj/build/x86_64-unknown-linux-gnu/miri-sysroot" "-Dwarnings" "-Dunused" "-Ainternal_features" "-Zui-testing" "--out-dir" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage1-tools/x86_64-unknown-linux-gnu/tmp/miri_ui/0/tests/pass/backtrace" "tests/pass/backtrace/backtrace-global-alloc.rs" "-Zmiri-disable-isolation" "--edition" "2021"

error: test got exit status: 1, but expected 0
 = note: compilation failed, but was expected to succeed

error: actual output differed from expected
---
- at RUSTLIB/std/src/rt.rs:LL:CC
+error: Undefined Behavior: calling a function whose parameter #2 has type usize passing argument of type std::ptr::Alignment
+  --> RUSTLIB/alloc/src/raw_vec/mod.rs:LL:CC
+   |
+LL |             AllocInit::Uninitialized => alloc.allocate(layout),
+   |                                         ^^^^^^^^^^^^^^^^^^^^^^ Undefined Behavior occurred here
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = help: this means these two types are not *guaranteed* to be ABI-compatible across all targets
+   = help: if you think this code should be accepted anyway, please report an issue with Miri
+   = note: BACKTRACE:
+   = note: inside `alloc::raw_vec::RawVecInner::try_allocate_in` at RUSTLIB/alloc/src/raw_vec/mod.rs:LL:CC
+   = note: inside `<u8 as std::slice::<impl [T]>::to_vec_in::ConvertVec>::to_vec::<std::alloc::Global>` at RUSTLIB/alloc/src/slice.rs:LL:CC
+   = note: inside `std::slice::<impl [u8]>::to_vec_in::<std::alloc::Global>` at RUSTLIB/alloc/src/slice.rs:LL:CC
+   = note: inside `std::slice::<impl [u8]>::to_vec` at RUSTLIB/alloc/src/slice.rs:LL:CC
+   = note: inside closure at RUSTLIB/std/src/sys/env/PLATFORM.rs:LL:CC
+   = note: inside `std::sys::pal::PLATFORM::small_c_string::run_with_cstr_stack::<std::option::Option<std::ffi::OsString>>` at RUSTLIB/std/src/sys/pal/PLATFORM/small_c_string.rs:LL:CC
+   = note: inside `std::sys::pal::PLATFORM::small_c_string::run_with_cstr::<std::option::Option<std::ffi::OsString>>` at RUSTLIB/std/src/sys/pal/PLATFORM/small_c_string.rs:LL:CC

[rust-bors]

☀️ Try build successful (CI)
Build commit: 12f11b8 (12f11b823b802aa4eee2c47457f3c84c324356c0, parent: 733dab558992d902d6d17576de1da768094e2cf3)

[rust-timer]

Finished benchmarking commit (12f11b8): comparison URL.

Overall result: ❌✅ regressions and improvements - please read the text below

Benchmarking this pull request means it may be perf-sensitive – we'll automatically label it not fit for rolling up. You can override this, but we strongly advise not to, due to possible changes in compiler perf.

Next Steps: If you can justify the regressions found in this try perf run, please do so in sufficient writing along with @rustbot label: +perf-regression-triaged. If not, please fix the regressions and do another perf run. If its results are neutral or positive, the label will be automatically removed.

@bors rollup=never
@rustbot label: -S-waiting-on-perf +perf-regression

Instruction count

Our most reliable metric. Used to determine the overall result above. However, even this metric can be noisy.

	mean	range	count
Regressions ❌ (primary)	0.6%	[0.2%, 0.9%]	5
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.3%	[-0.4%, -0.2%]	2
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.3%	[-0.4%, 0.9%]	7

Max RSS (memory usage)

Results (primary -2.8%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	5.2%	[5.2%, 5.2%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-4.4%	[-5.9%, -2.9%]	5
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-2.8%	[-5.9%, 5.2%]	6

Cycles

This benchmark run did not return any relevant results for this metric.

Binary size

Results (primary -0.1%, secondary -0.1%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	0.2%	[0.1%, 0.4%]	4
Regressions ❌ (secondary)	0.1%	[0.1%, 0.1%]	1
Improvements ✅ (primary)	-0.2%	[-0.3%, -0.0%]	12
Improvements ✅ (secondary)	-0.1%	[-0.3%, -0.0%]	6
All ❌✅ (primary)	-0.1%	[-0.3%, 0.4%]	16

Bootstrap: 466.742s -> 468.442s (0.36%)
Artifact size: 376.83 MiB -> 376.86 MiB (0.01%)