Add test for @gcsafe_ccall

Author: kpamnany

src/gcsafe_ccall.jl

@@ -7,15 +7,14 @@ const HAS_CCALL_GCSAFE = VERSION >= v"1.13.0-DEV.70" || v"1.12-DEV.2029" <= VERS
 """
     @gcsafe_ccall ...
 
-Call a foreign function just like [`@ccall`](https://docs.julialang.org/en/v1/base/c/#Base.@ccall), but marking it safe for the GC to run. This is
-useful for functions that may block, so that the GC isn't blocked from running, but may also
-be required to prevent deadlocks (see JuliaGPU/CUDA.jl#2261).
+Call a foreign function just like [`@ccall`](https://docs.julialang.org/en/v1/base/c/#Base.@ccall),
+but marking it safe for the GC to run. This is useful for functions that may block, so that the GC
+isn't blocked from running, but may also be required to prevent deadlocks (see JuliaGPU/CUDA.jl#2261).
 
-Note that this is generally only safe with non-Julia C functions that do not call back into
-the Julia directly.
+Note that this is generally only safe with non-Julia C functions that do not call back into Julia
+directly.
 """
 macro gcsafe_ccall end
-export @gcsafe_ccall
 
 if HAS_CCALL_GCSAFE
     macro gcsafe_ccall(expr)

test/Project.toml

@@ -1,5 +1,6 @@
 [deps]
 CodecLz4 = "5ba52731-8f18-5e0d-9241-30f10d1ec561"
+InteractiveUtils = "b77e0a4c-d291-57a0-90e8-8db25a27a240"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
 TestsForCodecPackages = "c2e61002-3542-480d-8b3c-5f05cc4f8554"
 TranscodingStreams = "3bb67fe8-82b1-5028-8e26-92a6c54297fa"

test/gcsafe_ccall.jl

@@ -0,0 +1,24 @@
+using CodecLz4
+using InteractiveUtils
+
+@testset "gcsafe_ccall" begin
+    function gc_safe_ccall()
+        # jl_errno is marked as JL_NOTSAFEPOINT
+        CodecLz4.@gcsafe_ccall jl_errno()::Cint
+    end
+
+    let llvm = sprint(code_llvm, gc_safe_ccall, ())
+        # check that the call works
+        @test gc_safe_ccall() isa Cint
+        # v1.10 is hard to test since ccall are just raw runtime pointers
+        if VERSION >= v"1.11"
+            if !CodecLz4.HAS_CCALL_GCSAFE
+                # check for the gc_safe store
+                @test occursin("jl_gc_safe_enter", llvm)
+                @test occursin("jl_gc_safe_leave", llvm)
+            else
+                @test occursin("store atomic i8 2", llvm)
+            end
+        end
+    end
+end

test/runtests.jl

@@ -2,6 +2,7 @@ using CodecLz4
 using Test
 
 @testset "CodecLz4.jl" begin
+    include("gcsafe_ccall.jl")
     include("headers/lz4.jl")
     include("headers/lz4frame.jl")
     include("headers/lz4hc.jl")