Parameter attributes on Cfunction closures sticks

src/codegen.cpp

@@ -5180,9 +5180,48 @@ static Function* gen_cfun_wrapper(
         // add nest parameter (pointer to jl_value_t* data array) after sret arg
         assert(closure_types);
         std::vector<Type*> fargt_sig(sig.fargt_sig);
+
         fargt_sig.insert(fargt_sig.begin() + sig.sret, T_pprjlvalue);
+
+        // Shift LLVM attributes for parameters one to the right, as
+        // we are adding the extra nest parameter after sret arg.
+        std::vector<std::pair<unsigned, AttributeSet>> newAttributes;
+        newAttributes.reserve(attributes.getNumAttrSets() + 1);
+        auto it = attributes.index_begin();
+
+        // Skip past FunctionIndex
+        if (it == AttributeList::AttrIndex::FunctionIndex) {
+            ++it;
+        }
+
+        // Move past ReturnValue and parameter return value
+        for (;it < AttributeList::AttrIndex::FirstArgIndex + sig.sret; ++it) {
+            if (attributes.hasAttributes(it)) {
+                newAttributes.emplace_back(it, attributes.getAttributes(it));
+            }
+        }
+
+        // Add the new nest attribute
+        AttrBuilder attrBuilder;
+        attrBuilder.addAttribute(Attribute::Nest);
+        newAttributes.emplace_back(it, AttributeSet::get(jl_LLVMContext, attrBuilder));
+
+        // Shift forward the rest of the attributes
+        for(;it < attributes.index_end(); ++it) {
+            if (attributes.hasAttributes(it)) {
+                newAttributes.emplace_back(it + 1, attributes.getAttributes(it));
+            }
+        }
+
+        // Remember to add back FunctionIndex
+        if (attributes.hasAttributes(AttributeList::AttrIndex::FunctionIndex)) {
+            newAttributes.emplace_back(AttributeList::AttrIndex::FunctionIndex,
+                                       attributes.getAttributes(AttributeList::AttrIndex::FunctionIndex));
+        }
+
+        // Create the new AttributeList
+        attributes = AttributeList::get(jl_LLVMContext, newAttributes);
         functype = FunctionType::get(sig.sret ? T_void : sig.prt, fargt_sig, /*isVa*/false);
-        attributes = attributes.addAttribute(jl_LLVMContext, 1 + sig.sret, Attribute::Nest);
     }
     else {
         functype = sig.functype();

test/ccall.jl

@@ -982,6 +982,26 @@ for (t, v) in ((Complex{Int32}, :ci32), (Complex{Int64}, :ci64),
     end
 end
 
+
+#issue 40164
+@testset "llvm parameter attributes on cfunction closures" begin
+    struct Struct40164
+        x::Cdouble
+        y::Cdouble
+        z::Cdouble
+    end
+
+    function test_40164()
+        ret = Struct40164[]
+        f = x::Struct40164 -> (push!(ret, x); nothing)
+        f_c = @cfunction($f, Cvoid, (Struct40164,))
+        ccall(f_c.ptr, Ptr{Cvoid}, (Struct40164,), Struct40164(0, 1, 2))
+        ret
+    end
+
+    @test test_40164() == [Struct40164(0, 1, 2)]
+end
+
 else
 
 @test_broken "cfunction: no support for closures on this platform"