Fix illegal attribute propagation in LLVM JIT.

macdice · macdice · commit bf1cfe77ed49 · 2024-04-10T10:46:15.000+12:00
Commit 7255943 started copying more attributes from AttributeTemplate to the functions we generate on the fly. In the case of deform functions, which return void, this meant that "noundef", from AttributeTemplate's return value (a Datum) was copied to a void type. Older LLVM releases were OK with that, but LLVM 18 crashes. Update our llvm_copy_attributes() function to skip copying the attribute for the return value, if the target function returns void. Thanks to Dmitry Dolgov for help chasing this down. Back-patch to all supported releases, like 7255943. Reported-by: Pavel Stehule <pavel.stehule@gmail.com> Reviewed-by: Dmitry Dolgov <9erthalion6@gmail.com> Discussion: https://postgr.es/m/CAFj8pRACpVFr7LMdVYENUkScG5FCYMZDDdSGNU-tch%2Bw98OxYg%40mail.gmail.com
diff --git a/src/backend/jit/llvm/llvmjit.c b/src/backend/jit/llvm/llvmjit.c
@@ -565,8 +565,11 @@ llvm_copy_attributes(LLVMValueRef v_from, LLVMValueRef v_to)
 	/* copy function attributes */
 	llvm_copy_attributes_at_index(v_from, v_to, LLVMAttributeFunctionIndex);
 
-	/* and the return value attributes */
-	llvm_copy_attributes_at_index(v_from, v_to, LLVMAttributeReturnIndex);
+	if (LLVMGetTypeKind(LLVMGetFunctionReturnType(v_to)) != LLVMVoidTypeKind)
+	{
+		/* and the return value attributes */
+		llvm_copy_attributes_at_index(v_from, v_to, LLVMAttributeReturnIndex);
+	}
 
 	/* and each function parameter's attribute */
 	param_count = LLVMCountParams(v_from);
