+struct load_ptr {
+ enum load_type type;
+ enum object_type object_type;
+ const void *ptr;
+ bool rev_bo;
+ /* Temporary place-holders for contexts. */
+ union {
+ int64_t s64;
+ uint64_t u64;
+ double d;
+ } u;
+ /*
+ * "field" is only needed when nested under a variant, in which
+ * case we cannot specialize the nested operations.
+ */
+ const struct lttng_event_field *field;
+};
+
+struct estack_entry {
+ enum entry_type type; /* For dynamic typing. */
+ union {
+ int64_t v;
+ double d;
+
+ struct {
+ const char *str;
+ size_t seq_len;
+ enum estack_string_literal_type literal_type;
+ } s;
+ struct load_ptr ptr;
+ } u;
+};
+
+struct estack {
+ int top; /* top of stack */
+ struct estack_entry e[FILTER_STACK_LEN];
+};
+
+/*
+ * Always use aliased type for ax/bx (top of stack).
+ * When ax/bx are S64, use aliased value.
+ */
+#define estack_ax_v ax
+#define estack_bx_v bx
+#define estack_ax_t ax_t
+#define estack_bx_t bx_t
+
+/*
+ * ax and bx registers can hold either integer, double or string.
+ */
+#define estack_ax(stack, top) \
+ ({ \
+ assert((top) > FILTER_STACK_EMPTY); \
+ &(stack)->e[top]; \
+ })
+
+#define estack_bx(stack, top) \
+ ({ \
+ assert((top) > FILTER_STACK_EMPTY + 1); \
+ &(stack)->e[(top) - 1]; \
+ })
+
+/*
+ * Currently, only integers (REG_S64) can be pushed into the stack.
+ */
+#define estack_push(stack, top, ax, bx, ax_t, bx_t) \
+ do { \
+ assert((top) < FILTER_STACK_LEN - 1); \
+ (stack)->e[(top) - 1].u.v = (bx); \
+ (stack)->e[(top) - 1].type = (bx_t); \
+ (bx) = (ax); \
+ (bx_t) = (ax_t); \
+ ++(top); \
+ } while (0)
+
+#define estack_pop(stack, top, ax, bx, ax_t, bx_t) \
+ do { \
+ assert((top) > FILTER_STACK_EMPTY); \
+ (ax) = (bx); \
+ (ax_t) = (bx_t); \
+ (bx) = (stack)->e[(top) - 2].u.v; \
+ (bx_t) = (stack)->e[(top) - 2].type; \
+ (top)--; \
+ } while (0)
+