+/* Validation stack */
+struct vstack_load {
+ enum load_type type;
+ enum object_type object_type;
+ const struct lttng_event_field *field;
+ bool rev_bo; /* reverse byte order */
+};
+
+struct vstack_entry {
+ enum entry_type type;
+ struct vstack_load load;
+};
+
+struct vstack {
+ int top; /* top of stack */
+ struct vstack_entry e[FILTER_STACK_LEN];
+};
+
+static inline
+void vstack_init(struct vstack *stack)
+{
+ stack->top = -1;
+}
+
+static inline
+struct vstack_entry *vstack_ax(struct vstack *stack)
+{
+ if (unlikely(stack->top < 0))
+ return NULL;
+ return &stack->e[stack->top];
+}
+
+static inline
+struct vstack_entry *vstack_bx(struct vstack *stack)
+{
+ if (unlikely(stack->top < 1))
+ return NULL;
+ return &stack->e[stack->top - 1];
+}
+
+static inline
+int vstack_push(struct vstack *stack)
+{
+ if (stack->top >= FILTER_STACK_LEN - 1) {
+ ERR("Stack full\n");
+ return -EINVAL;
+ }
+ ++stack->top;
+ return 0;
+}
+
+static inline
+int vstack_pop(struct vstack *stack)
+{
+ if (unlikely(stack->top < 0)) {
+ ERR("Stack empty\n");
+ return -EINVAL;
+ }
+ stack->top--;
+ return 0;
+}
+
+/* Execution stack */
+enum estack_string_literal_type {
+ ESTACK_STRING_LITERAL_TYPE_NONE,
+ ESTACK_STRING_LITERAL_TYPE_PLAIN,
+ ESTACK_STRING_LITERAL_TYPE_STAR_GLOB,
+};
+
+struct load_ptr {
+ enum load_type type;
+ enum object_type object_type;
+ const void *ptr;
+ size_t nr_elem;
+ bool rev_bo;
+ /* Temporary place-holders for contexts. */
+ union {
+ int64_t s64;
+ uint64_t u64;
+ double d;
+ } u;
+ 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)
+
+enum lttng_interpreter_type {
+ LTTNG_INTERPRETER_TYPE_S64,
+ LTTNG_INTERPRETER_TYPE_U64,
+ LTTNG_INTERPRETER_TYPE_SIGNED_ENUM,
+ LTTNG_INTERPRETER_TYPE_UNSIGNED_ENUM,
+ LTTNG_INTERPRETER_TYPE_DOUBLE,
+ LTTNG_INTERPRETER_TYPE_STRING,
+ LTTNG_INTERPRETER_TYPE_SEQUENCE,
+};
+
+/*
+ * Represents the output parameter of the lttng interpreter.
+ * Currently capturable field classes are integer, double, string and sequence
+ * of integer.
+ */
+struct lttng_interpreter_output {
+ enum lttng_interpreter_type type;
+ union {
+ int64_t s;
+ uint64_t u;
+ double d;
+
+ struct {
+ const char *str;
+ size_t len;
+ } str;
+ struct {
+ const void *ptr;
+ size_t nr_elem;