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Fix load and store for sizeof(T) == 0 #18

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Merged
merged 2 commits into from
Nov 30, 2024
Merged

Fix load and store for sizeof(T) == 0 #18

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8777ebb
Add test for Zero-sized types
vchuravy Nov 30, 2024
8220821
Fix fence usage
vchuravy Nov 30, 2024
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6 changes: 3 additions & 3 deletions ext/UnsafeAtomicsLLVM/atomics.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -191,10 +191,10 @@ end
if sizeof(T) == 0
# Mimicking what `Core.Intrinsics.atomic_pointerset` generates.
# See: https://github.com/JuliaLang/julia/blob/v1.7.2/src/cgutils.cpp#L1570-L1572
is_stronger_than_monotonic(order) || return :ptr
return quote
Core.Intrinsics.fence($(QuoteNode(order)))
ptr
is_stronger_than_monotonic(_valueof(order)) || return ptr
Core.Intrinsics.atomic_fence(_valueof(order))
return ptr
end
end
llvm_order = _valueof(llvm_from_julia_ordering(order()))
Expand Down
17 changes: 17 additions & 0 deletions test/UnsafeAtomicsLLVM.jl
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Expand Up @@ -10,13 +10,18 @@ function check_default_ordering(T::Type)
xs = T[rand(T), rand(T)]
x1 = rand(T)
x2 = rand(T)
check_default_ordering(xs, x1, x2)
end

function check_default_ordering(xs::AbstractArray{T}, x1::T, x2::T) where T
@debug "xs=$(repr(xs)) x1=$(repr(x1)) x2=$(repr(x2))"

ptr = llvmptr(xs, 1)
GC.@preserve xs begin
@test UnsafeAtomics.load(ptr) === xs[1]
UnsafeAtomics.store!(ptr, x1)
@test xs[1] === x1
sizeof(T) == 0 && return # CAS hangs on zero sized data...
desired = (old = x1, success = true)
@test UnsafeAtomics.cas!(ptr, x1, x2) === (old = x1, success = true)
@test xs[1] === x2
Expand All @@ -37,6 +42,10 @@ function test_explicit_ordering(T::Type = UInt)
xs = T[rand(T), rand(T)]
x1 = rand(T)
x2 = rand(T)
test_explicit_ordering(xs, x1, x2)
end

function test_explicit_ordering(xs::AbstractArray{T}, x1::T, x2::T) where T
@debug "xs=$(repr(xs)) x1=$(repr(x1)) x2=$(repr(x2))"

ptr = llvmptr(xs, 1)
Expand All @@ -45,6 +54,7 @@ function test_explicit_ordering(T::Type = UInt)
@test UnsafeAtomics.load(ptr, acquire) === xs[1]
UnsafeAtomics.store!(ptr, x1, release)
@test xs[1] === x1
sizeof(T) == 0 && return # CAS hangs on zero sized data...
desired = (old = x1, success = true)
@test UnsafeAtomics.cas!(ptr, x1, x2, acq_rel, acquire) === desired
@test xs[1] === x2
Expand Down Expand Up @@ -74,9 +84,16 @@ function test_explicit_ordering(T::Type = UInt)
end
end


@testset "UnsafeAtomicsLLVM" begin
@testset for T in inttypes
check_default_ordering(T)
test_explicit_ordering(T)
end

@testset "Zero-sized types" begin
@test sizeof(Nothing) == 0
check_default_ordering([nothing, nothing], nothing, nothing)
test_explicit_ordering([nothing, nothing], nothing, nothing)
end
end