Refine dummy_span.rs test #151244
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Refine dummy_span.rs test #151244
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@bors try jobs=x86_64-gnu-llvm-20-3 |
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Refine dummy_span.rs test try-job: x86_64-gnu-llvm-20-3
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…ulacrum Refine dummy_span.rs test The test that is introduced in rust-lang#128627 is a BBs order problem in LLVM. I'm not 100% confident in the following investigation, but I think this is presumably the result. Per the following content that is mentioned at https://llvm.org/docs/KeyInstructionsDebugInfo.html: > DWARF provides a helpful tool the compiler can employ to mitigate this jumpiness, the `is_stmt` flag, which indicates that an instruction is a recommended breakpoint location. However, LLVM’s current approach to deciding `is_stmt` placement essentially reduces down to “is the associated line number different to the previous instruction’s?”. Taking the example from https://rust.godbolt.org/z/GvToxj6vh. The partial assembly code with `SimplifyComparisonIntegral` is: ```asm .LBB40_21: .loc 6 14 16 is_stmt 1 ; RET = Ok(()) mov byte ptr [rsp + 79], 5 .loc 6 0 0 is_stmt 0 jmp .LBB40_23 ... .LBB40_23: .loc 6 18 1 is_stmt 1 lea rdi, [rsp + 112] ; drop(number_str) call qword ptr [rip + core[270d1373c8f6a07d]::ptr::drop_in_place::<alloc[206d51544a00c3e8]::string::String>@GOTPCREL] jmp .LBB40_27 ``` without `SimplifyComparisonIntegral`: ```asm .LBB40_22: .loc 6 14 16 is_stmt 1 ; RET = Ok(()) mov byte ptr [rsp + 79], 5 .loc 6 0 0 is_stmt 0 jmp .LBB40_27 ... .LBB40_26: .loc 6 18 2 is_stmt 0 mov al, byte ptr [rsp + 79] .loc 6 18 2 epilogue_begin add rsp, 360 .cfi_def_cfa_offset 8 ret .LBB40_27: ; same line number to the previous instruction, so don't place `is_stmt` flag. ; this flag is `is_stmt 0` that will follow the flag of `.LBB40_26`. .loc 6 18 1 lea rdi, [rsp + 112] ; drop(number_str) call qword ptr [rip + core[270d1373c8f6a07d]::ptr::drop_in_place::<alloc[206d51544a00c3e8]::string::String>@GOTPCREL] jmp .LBB40_26 ``` GDB doesn't step to `LBB40_27` due to `is_stmt 0`, so the next step is `__rust_begin_short_backtrace`. I have verified the new test works well with or without ``SimplifyComparisonIntegral`.
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…ulacrum Refine dummy_span.rs test The test that is introduced in rust-lang#128627 is a BBs order problem in LLVM. I'm not 100% confident in the following investigation, but I think this is presumably the result. Per the following content that is mentioned at https://llvm.org/docs/KeyInstructionsDebugInfo.html: > DWARF provides a helpful tool the compiler can employ to mitigate this jumpiness, the `is_stmt` flag, which indicates that an instruction is a recommended breakpoint location. However, LLVM’s current approach to deciding `is_stmt` placement essentially reduces down to “is the associated line number different to the previous instruction’s?”. Taking the example from https://rust.godbolt.org/z/GvToxj6vh. The partial assembly code with `SimplifyComparisonIntegral` is: ```asm .LBB40_21: .loc 6 14 16 is_stmt 1 ; RET = Ok(()) mov byte ptr [rsp + 79], 5 .loc 6 0 0 is_stmt 0 jmp .LBB40_23 ... .LBB40_23: .loc 6 18 1 is_stmt 1 lea rdi, [rsp + 112] ; drop(number_str) call qword ptr [rip + core[270d1373c8f6a07d]::ptr::drop_in_place::<alloc[206d51544a00c3e8]::string::String>@GOTPCREL] jmp .LBB40_27 ``` without `SimplifyComparisonIntegral`: ```asm .LBB40_22: .loc 6 14 16 is_stmt 1 ; RET = Ok(()) mov byte ptr [rsp + 79], 5 .loc 6 0 0 is_stmt 0 jmp .LBB40_27 ... .LBB40_26: .loc 6 18 2 is_stmt 0 mov al, byte ptr [rsp + 79] .loc 6 18 2 epilogue_begin add rsp, 360 .cfi_def_cfa_offset 8 ret .LBB40_27: ; same line number to the previous instruction, so don't place `is_stmt` flag. ; this flag is `is_stmt 0` that will follow the flag of `.LBB40_26`. .loc 6 18 1 lea rdi, [rsp + 112] ; drop(number_str) call qword ptr [rip + core[270d1373c8f6a07d]::ptr::drop_in_place::<alloc[206d51544a00c3e8]::string::String>@GOTPCREL] jmp .LBB40_26 ``` GDB doesn't step to `LBB40_27` due to `is_stmt 0`, so the next step is `__rust_begin_short_backtrace`. I have verified the new test works well with or without ``SimplifyComparisonIntegral`.
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Rollup of 8 pull requests Successful merges: - #145393 (Add codegen test for removing trailing zeroes from `NonZero`) - #149869 (std: avoid tearing `dbg!` prints) - #150065 (add CSE optimization tests for iterating over slice) - #150842 (Fix(lib/win/thread): Ensure `Sleep`'s usage passes over the requested duration under Win7) - #151244 (Refine dummy_span.rs test) - #151505 (Various refactors to the proc_macro bridge) - #151560 (relnotes: fix 1.93's `as_mut_array` methods) - #151577 (Rename `DepKindStruct` to `DepKindVTable`)
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The test that is introduced in #128627 is a BBs order problem in LLVM. I'm not 100% confident in the following investigation, but I think this is presumably the result.
Per the following content that is mentioned at https://llvm.org/docs/KeyInstructionsDebugInfo.html:
Taking the example from https://rust.godbolt.org/z/GvToxj6vh. The partial assembly code with
SimplifyComparisonIntegralis:without
SimplifyComparisonIntegral:GDB doesn't step to
LBB40_27due tois_stmt 0, so the next step is__rust_begin_short_backtrace. I have verified the new test works well with or without ``SimplifyComparisonIntegral`.