Make dyn*'s value backend type a pointer

[compiler-errors]

One tweak on top of Ralf's commit should fix using usize as a dyn*-coercible type, and should fix when we're using various other pointer types when LLVM opaque pointers is disabled.

r? @eholk but feel free to reassign
cc #107728 (comment) @RalfJung

[eholk]

@bors r+

[bors]

📌 Commit f4a0097f3119667b0f3d9ceceec9a49a4d1ec564 has been approved by eholk

It is now in the queue for this repository.

[erikdesjardins]

It would be good to add a case to tests/codegen/function-arguments.rs showing the ABI of dyn*; something like

// CHECK: { {{i8\*|ptr}}, {{i8\*|ptr}} } @dyn_star({{i8\*|ptr}} noundef align 1 %x.0, {{i8\*|ptr}} noalias noundef readonly align {{.*}} dereferenceable({{.*}}) %x.1)
#[no_mangle]
pub fn dyn_star(x: dyn* Drop) -> dyn* Drop {
  x
}

[RalfJung]

This can probably be hit by using a type such as

#[repr(C)]
struct S(usize);

and then doing S(0) as dyn* Send or something like that.

[compiler-errors]

That's broken for another reason (#104694), which I plan on rebasing/reworking once your Miri support for dyn* PR lands.

[RalfJung]

Yeah that's not surprising -- I assume so far this has only been tested with types that have Scalar layout.

(i32, i32) would also be an interesting testcase, that will have ScalarPair layout. Also better left for a future PR, probably.

[matthiaskrgr]

@bors rollup=never
bumping this up in the queue

[compiler-errors]

@bors r- i'll address ralf's comments today

[compiler-errors]

@bors r=eholk

[bors]

📌 Commit adc351cadf47722f149d30b40b0136a3cfcbfdef has been approved by eholk

It is now in the queue for this repository.

[compiler-errors]

@bors r-

[bors]

⌛ Testing commit 7f798c2 with merge 23d857844c85097003539b8f2e2b9a4707cf266a...

[bors]

💔 Test failed - checks-actions

[compiler-errors]

It didn't even start testing?

@bors retry

[bors]

⌛ Testing commit 7f798c2 with merge 6910affab408ca9a6fcf649ae16a3b58d1d7c1a7...

[bors]

💔 Test failed - checks-actions

[rust-log-analyzer]

The job x86_64-mingw-2 failed! Check out the build log: (web) (plain)

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

[2579/3025] Linking CXX static library lib\libLLVMInstrumentation.a
[2580/3025] Building CXX object tools/llvm-ar/CMakeFiles/llvm-ar.dir/llvm-ar.cpp.obj
[2581/3025] Linking CXX executable bin\not.exe
[2582/3025] Linking CXX static library lib\libLLVMInstCombine.a
FAILED: lib/libLLVMInstCombine.a 
cmd.exe /C "cd . && "C:\Program Files\CMake\bin\cmake.exe" -E rm -f lib\libLLVMInstCombine.a && D:\a\rust\rust\mingw64\bin\ar.exe qc lib\libLLVMInstCombine.a  lib/Transforms/InstCombine/CMakeFiles/LLVMInstCombine.dir/InstructionCombining.cpp.obj lib/Transforms/InstCombine/CMakeFiles/LLVMInstCombine.dir/InstCombineAddSub.cpp.obj lib/Transforms/InstCombine/CMakeFiles/LLVMInstCombine.dir/InstCombineAtomicRMW.cpp.obj lib/Transforms/InstCombine/CMakeFiles/LLVMInstCombine.dir/InstCombineAndOrXor.cpp.obj lib/Transforms/InstCombine/CMakeFiles/LLVMInstCombine.dir/InstCombineCalls.cpp.obj lib/Transforms/InstCombine/CMakeFiles/LLVMInstCombine.dir/InstCombineCasts.cpp.obj lib/Transforms/InstCombine/CMakeFiles/LLVMInstCombine.dir/InstCombineCompares.cpp.obj lib/Transforms/InstCombine/CMakeFiles/LLVMInstCombine.dir/InstCombineLoadStoreAlloca.cpp.obj lib/Transforms/InstCombine/CMakeFiles/LLVMInstCombine.dir/InstCombineMulDivRem.cpp.obj lib/Transforms/InstCombine/CMakeFiles/LLVMInstCombine.dir/InstCombineNegator.cpp.obj lib/Transforms/InstCombine/CMakeFiles/LLVMInstCombine.dir/InstCombinePHI.cpp.obj lib/Transforms/InstCombine/CMakeFiles/LLVMInstCombine.dir/InstCombineSelect.cpp.obj lib/Transforms/InstCombine/CMakeFiles/LLVMInstCombine.dir/InstCombineShifts.cpp.obj lib/Transforms/InstCombine/CMakeFiles/LLVMInstCombine.dir/InstCombineSimplifyDemanded.cpp.obj lib/Transforms/InstCombine/CMakeFiles/LLVMInstCombine.dir/InstCombineVectorOps.cpp.obj && D:\a\rust\rust\mingw64\bin\ranlib.exe lib\libLLVMInstCombine.a && cd ."
D:\a\rust\rust\mingw64\bin\ranlib.exe: could not create temporary file whilst writing archive: no more archived files
[2583/3025] Linking CXX static library lib\libLLVMObjCARCOpts.a
[2584/3025] Linking CXX static library lib\libLLVMLinker.a
[2585/3025] Linking CXX executable bin\yaml-bench.exe
[2586/3025] Building CXX object tools/llvm-lto/CMakeFiles/llvm-lto.dir/llvm-lto.cpp.obj
[2586/3025] Building CXX object tools/llvm-lto/CMakeFiles/llvm-lto.dir/llvm-lto.cpp.obj
[2587/3025] Linking CXX executable bin\UnicodeNameMappingGenerator.exe
[2588/3025] Linking CXX executable bin\llvm-config.exe
[2589/3025] Linking CXX static library lib\libLLVMVectorize.a
ninja: build stopped: subcommand failed.
command did not execute successfully, got: exit code: 1


build script failed, must exit now', C:\Users\runneradmin\.cargo\registry\src\index.crates.io-6f17d22bba15001f\cmake-0.1.48\src\lib.rs:975:5
 finished in 286.471 seconds
Build completed unsuccessfully in 0:06:31
Build completed unsuccessfully in 0:06:31
make: *** [Makefile:80: ci-mingw-subset-2] Error 1

[erikdesjardins]

CI error is spurious, opened #108227 to track it

[compiler-errors]

Thanks, in that case

@bors retry

[bors]

⌛ Testing commit 7f798c2 with merge 73f4019...

[rust-log-analyzer]

The job x86_64-mingw-1 failed! Check out the build log: (web) (plain)

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

[2529/3025] Building CXX object lib/XRay/CMakeFiles/LLVMXRay.dir/Trace.cpp.obj
[2530/3025] Building CXX object lib/XRay/CMakeFiles/LLVMXRay.dir/RecordPrinter.cpp.obj
[2531/3025] Linking CXX static library lib\libLLVMDlltoolDriver.a
FAILED: lib/libLLVMDlltoolDriver.a 
cmd.exe /C "cd . && "C:\Program Files\CMake\bin\cmake.exe" -E rm -f lib\libLLVMDlltoolDriver.a && D:\a\rust\rust\mingw64\bin\ar.exe qc lib\libLLVMDlltoolDriver.a  lib/ToolDrivers/llvm-dlltool/CMakeFiles/LLVMDlltoolDriver.dir/DlltoolDriver.cpp.obj && D:\a\rust\rust\mingw64\bin\ranlib.exe lib\libLLVMDlltoolDriver.a && cd ."
D:\a\rust\rust\mingw64\bin\ranlib.exe: could not create temporary file whilst writing archive: no more archived files
[2532/3025] Linking CXX static library lib\libLLVMDebugInfoDWARF.a
[2533/3025] Linking CXX static library lib\libLLVMObjCopy.a
[2534/3025] Linking CXX static library lib\libLLVMJITLink.a
[2535/3025] Building CXX object lib/XRay/CMakeFiles/LLVMXRay.dir/InstrumentationMap.cpp.obj
[2535/3025] Building CXX object lib/XRay/CMakeFiles/LLVMXRay.dir/InstrumentationMap.cpp.obj
[2536/3025] Linking CXX static library lib\libLLVMRuntimeDyld.a
[2537/3025] Linking CXX static library lib\libLLVMDebugInfoPDB.a
[2538/3025] Linking CXX static library lib\libLLVMObjectYAML.a
ninja: build stopped: subcommand failed.
command did not execute successfully, got: exit code: 1


build script failed, must exit now', C:\Users\runneradmin\.cargo\registry\src\index.crates.io-6f17d22bba15001f\cmake-0.1.48\src\lib.rs:975:5
 finished in 240.900 seconds
Build completed unsuccessfully in 0:06:30
Build completed unsuccessfully in 0:06:30
make: *** [Makefile:78: ci-mingw-subset-1] Error 1

[bors]

☀️ Test successful - checks-actions
Approved by: eholk
Pushing 73f4019 to master...

[rust-timer]

Finished benchmarking commit (73f4019): comparison URL.

Overall result: no relevant changes - no action needed

@rustbot label: -perf-regression

Instruction count

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

Max RSS (memory usage)

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.1%	[-0.1%, -0.1%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-0.1%	[-0.1%, -0.1%]	1

Cycles

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-2.8%	[-2.8%, -2.8%]	1
All ❌✅ (primary)	-	-	0