Add `as_rchunks` (and friends) to slices by scottmcm · Pull Request #78818 · rust-lang/rust

scottmcm · 2020-11-06T22:00:16Z

@est31 mentioned (#76354 (comment)) that, for completeness, there needed to be an as_chunks-like method that chunks from the end (with the remainder at the beginning) like rchunks does.

So here's a PR for as_rchunks: &[T] -> (&[T], &[[T; N]]) and as_rchunks_mut: &mut [T] -> (&mut [T], &mut [[T; N]]).

But as I was doing this and copy-pasting from_raw_parts calls, I thought that I should extract that into an unsafe method. It started out a private helper, but it seemed like as_chunks_unchecked could be reasonable as a "real" method, so I added docs and made it public. Let me know if you think it doesn't pull its weight.

rust-highfive · 2020-11-06T22:00:19Z

r? @sfackler

(rust_highfive has picked a reviewer for you, use r? to override)

scottmcm · 2020-11-06T23:02:33Z

library/core/src/slice/mod.rs

It wasn't obvious to me whether this should be as_chunks_mut_unchecked or as_chunks_unchecked_mut. I could see precedent for both.

It looks like unchecked_mut is more frequently used but mut_unchecked sounds better to me 😆

It looks like unchecked_mut has more precedent in slice and iterator APIs so maybe we should roll with that.

I'm very sad that we have a nice mix of both unchecked_mut and mut_unchecked 🥲

scottmcm · 2020-11-06T23:06:12Z

src/test/codegen/slice-as_chunks.rs

I wanted to ensure I didn't accidentally introduce extra instructions with the refactor, so codegen test. It did change, but only from lshr/and/and to and/and/lshr exact, which is a thoroughly uninteresting difference.

Dylan-DPC-zz · 2020-11-24T17:02:40Z

r? @KodrAus

KodrAus · 2021-01-14T02:29:40Z

Thanks @scottmcm!

r=me with as_chunks_unchecked_mut.

scottmcm · 2021-01-16T06:21:24Z

@bors r=KodrAus

bors · 2021-01-16T06:21:26Z

📌 Commit 132307c has been approved by KodrAus

Add `as_rchunks` (and friends) to slices `@est31` mentioned (rust-lang#76354 (comment)) that, for completeness, there needed to be an `as_chunks`-like method that chunks from the end (with the remainder at the beginning) like `rchunks` does. So here's a PR for `as_rchunks: &[T] -> (&[T], &[[T; N]])` and `as_rchunks_mut: &mut [T] -> (&mut [T], &mut [[T; N]])`. But as I was doing this and copy-pasting `from_raw_parts` calls, I thought that I should extract that into an unsafe method. It started out a private helper, but it seemed like `as_chunks_unchecked` could be reasonable as a "real" method, so I added docs and made it public. Let me know if you think it doesn't pull its weight.

m-ou-se · 2021-01-16T17:28:56Z

@bors r-

This failed in #81085 (comment):

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

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

Some tests failed in compiletest suite=codegen mode=codegen host=x86_64-unknown-linux-gnu target=x86_64-unknown-linux-gnu

failures:

---- [codegen] codegen/slice-as_chunks.rs stdout ----

error: verification with 'FileCheck' failed
status: exit code: 1
command: "/checkout/obj/build/tmp/distcheck/build/x86_64-unknown-linux-gnu/llvm/build/bin/FileCheck" "--input-file" "/checkout/obj/build/tmp/distcheck/build/x86_64-unknown-linux-gnu/test/codegen/slice-as_chunks/slice-as_chunks.ll" "/checkout/obj/build/tmp/distcheck/src/test/codegen/slice-as_chunks.rs"
------------------------------------------

------------------------------------------
stderr:
stderr:
------------------------------------------
/checkout/obj/build/tmp/distcheck/src/test/codegen/slice-as_chunks.rs:12:17: error: CHECK-NEXT: expected string not found in input
 // CHECK-NEXT: lshr i64 %x.1, 2
                ^
/checkout/obj/build/tmp/distcheck/build/x86_64-unknown-linux-gnu/test/codegen/slice-as_chunks/slice-as_chunks.ll:15:2: note: scanning from here
 %len.i = and i64 %x.1, -4
 ^
/checkout/obj/build/tmp/distcheck/build/x86_64-unknown-linux-gnu/test/codegen/slice-as_chunks/slice-as_chunks.ll:15:9: note: possible intended match here
 %len.i = and i64 %x.1, -4


Input file: /checkout/obj/build/tmp/distcheck/build/x86_64-unknown-linux-gnu/test/codegen/slice-as_chunks/slice-as_chunks.ll
Check file: /checkout/obj/build/tmp/distcheck/src/test/codegen/slice-as_chunks.rs

-dump-input=help explains the following input dump.
Input was:
<<<<<<
           .
           .
           .
           .
          10: @alloc47 = private unnamed_addr constant <{ i8*, [16 x i8] }> <{ i8* getelementptr inbounds (<{ [63 x i8] }>, <{ [63 x i8] }>* @alloc46, i32 0, i32 0, i32 0), [16 x i8] c"?\00\00\00\00\00\00\00[\00\00\00\05\00\00\00" }>, align 8
          11: 
          12: ; Function Attrs: nonlazybind uwtable
          13: define { [0 x [4 x i8]]*, i64 } @chunks4([0 x i8]* noalias nonnull readonly align 1 %x.0, i64 %x.1) unnamed_addr #0 {
          14: start:
          15:  %len.i = and i64 %x.1, -4
next:12'0      X~~~~~~~~~~~~~~~~~~~~~~~~ error: no match found
next:12'1             ?                  possible intended match
          16:  %_71.i.i.i = icmp slt i64 %len.i, 0
next:12'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
          17:  br i1 %_71.i.i.i, label %bb6.i.i.i, label %"_ZN4core5slice29_$LT$impl$u20$$u5b$T$u5d$$GT$9as_chunks17h5eb20245ca5b2171E.exit"
next:12'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
          18: 
next:12'0     ~
          19: bb6.i.i.i: ; preds = %start
next:12'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~
          20: ; call core::panicking::panic
next:12'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           .
           .
>>>>>>

---
test result: FAILED. 207 passed; 1 failed; 33 ignored; 0 measured; 0 filtered out; finished in 4.09s



command did not execute successfully: "/checkout/obj/build/tmp/distcheck/build/x86_64-unknown-linux-gnu/stage0-tools-bin/compiletest" "--compile-lib-path" "/checkout/obj/build/tmp/distcheck/build/x86_64-unknown-linux-gnu/stage2/lib" "--run-lib-path" "/checkout/obj/build/tmp/distcheck/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/x86_64-unknown-linux-gnu/lib" "--rustc-path" "/checkout/obj/build/tmp/distcheck/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "--src-base" "/checkout/obj/build/tmp/distcheck/src/test/codegen" "--build-base" "/checkout/obj/build/tmp/distcheck/build/x86_64-unknown-linux-gnu/test/codegen" "--stage-id" "stage2-x86_64-unknown-linux-gnu" "--suite" "codegen" "--mode" "codegen" "--target" "x86_64-unknown-linux-gnu" "--host" "x86_64-unknown-linux-gnu" "--llvm-filecheck" "/checkout/obj/build/tmp/distcheck/build/x86_64-unknown-linux-gnu/llvm/build/bin/FileCheck" "--host-rustcflags" "-Crpath -O -Cdebuginfo=0 -Zunstable-options  -Lnative=/checkout/obj/build/tmp/distcheck/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "--target-rustcflags" "-Crpath -O -Cdebuginfo=0 -Zunstable-options  -Lnative=/checkout/obj/build/tmp/distcheck/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "--docck-python" "/usr/bin/python3" "--lldb-python" "/usr/bin/python3" "--gdb" "/usr/bin/gdb" "--llvm-version" "11.0.1-rust-1.51.0-nightly" "--llvm-components" "aarch64 aarch64asmparser aarch64codegen aarch64desc aarch64disassembler aarch64info aarch64utils aggressiveinstcombine all all-targets analysis arm armasmparser armcodegen armdesc armdisassembler arminfo armutils asmparser asmprinter avr avrasmparser avrcodegen avrdesc avrdisassembler avrinfo binaryformat bitreader bitstreamreader bitwriter cfguard codegen core coroutines coverage debuginfocodeview debuginfodwarf debuginfogsym debuginfomsf debuginfopdb demangle dlltooldriver dwarflinker engine executionengine extensions frontendopenmp fuzzmutate globalisel gtest gtest_main hexagon hexagonasmparser hexagoncodegen hexagondesc hexagondisassembler hexagoninfo instcombine instrumentation interpreter ipo irreader jitlink libdriver lineeditor linker lto mc mca mcdisassembler mcjit mcparser mips mipsasmparser mipscodegen mipsdesc mipsdisassembler mipsinfo mirparser msp430 msp430asmparser msp430codegen msp430desc msp430disassembler msp430info native nativecodegen nvptx nvptxcodegen nvptxdesc nvptxinfo objcarcopts object objectyaml option orcerror orcjit passes powerpc powerpcasmparser powerpccodegen powerpcdesc powerpcdisassembler powerpcinfo profiledata remarks riscv riscvasmparser riscvcodegen riscvdesc riscvdisassembler riscvinfo riscvutils runtimedyld scalaropts selectiondag sparc sparcasmparser sparccodegen sparcdesc sparcdisassembler sparcinfo support symbolize systemz systemzasmparser systemzcodegen systemzdesc systemzdisassembler systemzinfo tablegen target testingsupport textapi transformutils vectorize webassembly webassemblyasmparser webassemblycodegen webassemblydesc webassemblydisassembler webassemblyinfo windowsmanifest x86 x86asmparser x86codegen x86desc x86disassembler x86info xray" "--cc" "" "--cxx" "" "--cflags" "" "--adb-path" "adb" "--adb-test-dir" "/data/tmp/work" "--android-cross-path" "" "--color" "always"


failed to run: /checkout/obj/build/tmp/distcheck/build/bootstrap/debug/bootstrap test --stage 2
Build completed unsuccessfully in 0:19:44
Build completed unsuccessfully in 0:19:44
make: *** [check] Error 1
Makefile:42: recipe for target 'check' failed

command did not execute successfully: "make" "check"
expected success, got: exit code: 2

scottmcm · 2021-01-16T22:34:25Z

@bors rollup=never

Sigh, codegen tests.

This fixed things the last time I had a problem like this. And plausibly will here too -- the check it's failing on is for the high bit being set in the length of the slice, which is a check that's only in a debug_assert.

scottmcm · 2021-01-16T22:53:36Z

@bors r=KodrAus

bors · 2021-01-16T22:53:37Z

📌 Commit 6bcaba9 has been approved by KodrAus

bors · 2021-01-17T05:44:01Z

⌛ Testing commit 6bcaba9 with merge 49d7889...

bors · 2021-01-17T08:44:06Z

☀️ Test successful - checks-actions
Approved by: KodrAus
Pushing 49d7889 to master...

rust-highfive assigned sfackler Nov 6, 2020

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Nov 6, 2020

scottmcm force-pushed the as_rchunks branch from 8bcbfa2 to b3c0115 Compare November 6, 2020 23:00

scottmcm commented Nov 6, 2020

View reviewed changes

scottmcm mentioned this pull request Nov 6, 2020

Does [T]::array_chunks really need to be an iterator? #76354

Closed

rust-highfive assigned KodrAus and unassigned sfackler Nov 24, 2020

crlf0710 added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Dec 11, 2020

scottmcm added 2 commits January 15, 2021 21:24

Add as_rchunks (and friends) to slices

ae4b5a2

Rename as_chunks_mut_unchecked -> as_chunks_unchecked_mut

132307c

scottmcm force-pushed the as_rchunks branch from b3c0115 to 132307c Compare January 16, 2021 05:25

bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Jan 16, 2021

m-ou-se mentioned this pull request Jan 16, 2021

Rollup of 17 pull requests #81085

Closed

bors added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels Jan 16, 2021

Try ignore-debug in the codegen test

6bcaba9

This fixed things the last time I had a problem like this. And plausibly will here too -- the check it's failing on is for the high bit being set in the length of the slice, which is a check that's only in a debug_assert.

bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Jan 16, 2021

bors added the merged-by-bors This PR was explicitly merged by bors. label Jan 17, 2021

bors merged commit 49d7889 into rust-lang:master Jan 17, 2021

rustbot added this to the 1.51.0 milestone Jan 17, 2021

scottmcm deleted the as_rchunks branch January 25, 2021 02:03

kennytm mentioned this pull request Sep 25, 2021

Tracking Issue for slice::array_chunks #74985

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7 tasks

scottmcm mentioned this pull request Dec 3, 2021

Tracking Issue for split_array #90091

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