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Support interpolated function pointers in @gcsafe_ccall on Julia < 1.12 #24

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Merged
maleadt merged 1 commit into from
Sep 30, 2026
Merged

Support interpolated function pointers in @gcsafe_ccall on Julia < 1.12 #24

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25 changes: 22 additions & 3 deletions src/ccalls.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -120,18 +120,36 @@ else
# we need to do so ourselves in order to insert a jl_gc_safe_enter|leave
# just around the inner ccall

# like Base, support calling a function pointer that is interpolated with `$`
statements = []
if Meta.isexpr(func, :$)
fptr = gensym("fptr")
push!(statements, :($fptr = $(esc(func.args[1]))))
name = QuoteNode(func.args[1])
push!(statements, quote
if !isa($fptr, Ptr{Cvoid})
throw(ArgumentError(LazyString("interpolated function `", $name,
"` was not a Ptr{Cvoid}, but ",
typeof($fptr))))
end
end)
func = fptr
else
func = esc(func)
end

cconvert_exprs = []
cconvert_args = []
for (typ, arg) in zip(types, args)
var = gensym("$(func)_cconvert")
var = gensym("cconvert")
push!(cconvert_args, var)
push!(cconvert_exprs, :($var = Base.cconvert($(esc(typ)), $(esc(arg)))))
end

unsafe_convert_exprs = []
unsafe_convert_args = []
for (typ, arg) in zip(types, cconvert_args)
var = gensym("$(func)_unsafe_convert")
var = gensym("unsafe_convert")
push!(unsafe_convert_args, var)
push!(unsafe_convert_exprs, :($var = Base.unsafe_convert($(esc(typ)), $arg)))
end
Expand All @@ -141,7 +159,7 @@ else

gc_state = @ccall(jl_gc_safe_enter()::Int8)
ret = ccall(
$(esc(func)), $(esc(rettype)), $(Expr(:tuple, map(esc, types)...)),
$func, $(esc(rettype)), $(Expr(:tuple, map(esc, types)...)),
$(unsafe_convert_args...)
)
@ccall(jl_gc_safe_leave(gc_state::Int8)::Cvoid)
Expand All @@ -150,6 +168,7 @@ else

return quote
@inline
$(statements...)
$(cconvert_exprs...)
GC.@preserve $(cconvert_args...) $(call)
end
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8 changes: 8 additions & 0 deletions test/runtests.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -62,6 +62,14 @@ using IOCapture
@gcsafe_ccall jl_rand()::UInt64
end

# interpolated function pointers
fptr = cglobal(:jl_rand)
@test (@gcsafe_ccall $fptr()::UInt64) isa UInt64
if !GPUToolbox.HAS_CCALL_GCSAFE
# like `@ccall` on these Julia versions, the fallback checks the pointer
@test_throws ArgumentError @gcsafe_ccall $(nothing)()::UInt64
end

let llvm = sprint(code_llvm, gc_safe_ccall, ())
# check that the call works
@test gc_safe_ccall() isa UInt64
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