codegen: mark write barrier field load as volatile #59559
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vtjnash
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GC
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This LGTM, there's very little optimizations that are legal around these GC stores at that point |
This is as an alternative to changing all allocation functions to mutating all memory and returning an aliasing pointer. This operates usually late in the pipeline, so either should not make much difference, but I think it should suffice to mark this volatile to prevent any de-duplication of this load, and this should also be most conservative. Fixes #59547 Written by Claude.
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why volitile rather than sequentially consistent? |
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There aren't any atomic requirements there. It just can't assume the value that was there cannot change. |
KristofferC
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Sep 17, 2025
This is as an alternative to changing all allocation functions to mutating all memory and returning an aliasing pointer. This operates usually late in the pipeline, so either should not make much difference, but I think it should suffice to mark this volatile to prevent any de-duplication of this load, and this should also be most conservative for GC but more liberal for other optimizations. Fixes #59547 Produced with dubious help by Claude. (cherry picked from commit 218f691)
KristofferC
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Sep 17, 2025
This is as an alternative to changing all allocation functions to mutating all memory and returning an aliasing pointer. This operates usually late in the pipeline, so either should not make much difference, but I think it should suffice to mark this volatile to prevent any de-duplication of this load, and this should also be most conservative for GC but more liberal for other optimizations. Fixes #59547 Produced with dubious help by Claude. (cherry picked from commit 218f691)
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KristofferC
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xal-0
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Sep 30, 2025
This is as an alternative to changing all allocation functions to mutating all memory and returning an aliasing pointer. This operates usually late in the pipeline, so either should not make much difference, but I think it should suffice to mark this volatile to prevent any de-duplication of this load, and this should also be most conservative for GC but more liberal for other optimizations. Fixes JuliaLang#59547 Produced with dubious help by Claude.
DilumAluthge
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Backported PRs: - [x] #57523 <!-- Remove usages of weak symbols --> - [x] #58127 <!-- [DOC] Update installation docs: /downloads/ => /install/ --> - [x] #58202 <!-- [release-1.11] malloc: use jl_get_current_task to fix null check --> - [x] #58554 <!-- remove workaround for controlling terminal behavior in repl_cmd --> - [x] #58584 <!-- Make `Ptr` values static-show w/ type-information --> - [x] #59062 <!-- remove a testset from MMAP that might cause CI to now fail on Windows --> - [x] #59300 <!-- Update the developer docs to reflect the use of JuliaSyntax.jl --> - [x] #57604 <!-- `@nospecialize` for `string_index_err` --> - [x] #59329 <!-- aotcompile: destroy LLVM context after serializing combined module --> - [x] #59418 <!-- Fix startup when history file is bad --> - [x] #56890 <!-- Enable getting non-boxed LLVM type from Julia Type --> - [x] #59559 <!-- codegen: mark write barrier field load as volatile --> - [x] #59572 <!-- Only apply Base.Sort.SubArrayOptimization when iszero(v.offset1) --> Need manual backport: - [ ] #56329 <!-- loading: clean up more concurrency issues --> - [ ] #56956 <!-- Add "mea culpa" to foreign module assignment error. --> - [ ] #57035 <!-- linux: workaround to avoid deadlock inside dl_iterate_phdr in glibc --> - [ ] #57089 <!-- Block thread from receiving profile signal with stackwalk lock --> - [ ] #57249 <!-- restore non-freebsd-unix fix for profiling --> - [ ] #58011 <!-- Remove try-finally scope from `@time_imports` `@trace_compile` `@trace_dispatch` --> - [ ] #58062 <!-- remove unnecessary edge from `exp_impl` to `pow` --> - [ ] #58157 <!-- add showing a string to REPL precompile workload --> - [ ] #58209 <!-- Specialize `one` for the `SizedArray` test helper --> - [ ] #58356 <!-- codegen: remove readonly from abstract type calling convention --> - [ ] #58415 <!-- [REPL] more reliable extension loading --> - [ ] #58510 <!-- Don't filter `Core` methods from newly-inferred list --> - [ ] #58110 <!-- relax dispatch for the `IteratorSize` method for `Generator` --> - [ ] #58965 <!-- Fix `hygienic-scope`s in inner macro expansions --> - [ ] #58971 <!-- Fix alignment of failed precompile jobs on CI --> - [ ] #59066 <!-- build: Also pass -fno-strict-aliasing for C++ --> - [ ] #59428 <!-- Correctly set the variant bits of uuid1 --> Contains multiple commits, manual intervention needed: - [ ] #55877 <!-- fix FileWatching designs and add workaround for a stat bug on Apple --> - [ ] #56755 <!-- docs: fix scope type of a `struct` to hard --> - [ ] #57809 <!-- Fix fptrunc Float64 -> Float16 rounding through Float32 --> - [ ] #57398 <!-- Make remaining float intrinsics require float arguments --> - [ ] #56351 <!-- Fix `--project=@script` when outside script directory --> - [ ] #57129 <!-- clarify that time_ns is monotonic --> - [ ] #58134 <!-- Note annotated string API is experimental in Julia 1.11 in HISTORY.md --> - [ ] #58401 <!-- check that hashing of types does not foreigncall (`jl_type_hash` is concrete evaluated) --> - [ ] #58435 <!-- Fix layout flags for types that have oddly sized primitive type fields --> - [ ] #58483 <!-- Fix tbaa usage when storing into heap allocated immutable structs --> - [ ] #58512 <!-- Make more types jl_static_show readably --> - [ ] #58012 <!-- Re-enable tab completion of kwargs for large method tables --> - [ ] #58683 <!-- Add 0 predecessor to entry basic block and handle it in inlining --> - [ ] #59112 <!-- Add builtin function name to add methods error --> - [ ] #56823 <!-- Make version of opaque closure constructor in world --> - [ ] #59467 <!-- `CoreLogging`: prevent some `Annotated*`-related instability --> Non-merged PRs with backport label: - [ ] #59450 <!-- Propagate Addrspaces: fix lift of memset --> - [ ] #58848 <!-- Set array size only when safe to do so --> - [ ] #55958 <!-- also redirect JL_STDERR etc. when redirecting to devnull --> - [ ] #55956 <!-- Make threadcall gc safe --> - [ ] #55534 <!-- Set stdlib sources as read-only during installation --> - [ ] #55499 <!-- propagate the terminal's `displaysize` to the `IOContext` used by the REPL --> - [ ] #55458 <!-- Allow for generically extracting unannotated string --> - [ ] #55457 <!-- Make AnnotateChar equality consider annotations --> - [ ] #55220 <!-- `isfile_casesensitive` fixes on Windows --> - [ ] #53957 <!-- tweak how filtering is done for what packages should be precompiled --> - [ ] #51479 <!-- prevent code loading from lookin in the versioned environment when building Julia --> - [ ] #50813 <!-- More doctests for Sockets and capitalization fix --> - [ ] #50157 <!-- improve docs for `@inbounds` and `Base.@propagate_inbounds` --> --------- Co-authored-by: Dilum Aluthge <[email protected]> Co-authored-by: Sam Schweigel <[email protected]> Co-authored-by: Cody Tapscott <[email protected]> Co-authored-by: Jameson Nash <[email protected]> Co-authored-by: Adam Wheeler <[email protected]> Co-authored-by: Neven Sajko <[email protected]> Co-authored-by: Shuhei Kadowaki <[email protected]> Co-authored-by: Ian Butterworth <[email protected]> Co-authored-by: William Moses <[email protected]> Co-authored-by: Valentin Churavy <[email protected]> Co-authored-by: Lilith Orion Hafner <[email protected]>
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This is as an alternative to changing all allocation functions to mutating all memory and returning an aliasing pointer. This operates usually late in the pipeline, so either should not make much difference, but I think it should suffice to mark this volatile to prevent any de-duplication of this load, and this should also be most conservative for GC but more liberal for other optimizations.
Fixes #59547
Produced with dubious help by Claude.