so... jai :D

src/builtins.zig

@@ -0,0 +1,25 @@
+const llvm = @import("llvm_api.zig");
+const c = llvm.c;
+
+pub const Builtins = struct {
+    printf_fn: c.LLVMValueRef,
+    calloc_fn: c.LLVMValueRef,
+
+    pub fn init(module: c.LLVMModuleRef, ctx: c.LLVMContextRef) Builtins {
+        const ptr_type = c.LLVMPointerTypeInContext(ctx, 0);
+        const i64_type = c.LLVMInt64TypeInContext(ctx);
+        const i32_type = c.LLVMInt32TypeInContext(ctx);
+
+        // Declare: int printf(const char*, ...)
+        var printf_params = [_]c.LLVMTypeRef{ptr_type};
+        const printf_type = c.LLVMFunctionType(i32_type, &printf_params, 1, 1);
+        const printf_fn = c.LLVMAddFunction(module, "printf", printf_type);
+
+        // Declare: void* calloc(size_t count, size_t size)
+        var calloc_params = [_]c.LLVMTypeRef{ i64_type, i64_type };
+        const calloc_type = c.LLVMFunctionType(ptr_type, &calloc_params, 2, 0);
+        const calloc_fn = c.LLVMAddFunction(module, "calloc", calloc_type);
+
+        return .{ .printf_fn = printf_fn, .calloc_fn = calloc_fn };
+    }
+};