X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fcommon%2Ffilter%2Ffilter-visitor-generate-bytecode.c;fp=src%2Fcommon%2Ffilter%2Ffilter-visitor-generate-bytecode.c;h=699273c3d984f7e9aba6f4ee51b0d77e2fa666d1;hp=0000000000000000000000000000000000000000;hb=e4d2f27a74baf6942ac8fcafd5ea53e775ceceb3;hpb=d44f9a1878031bfdb6ceee49d817430b11f0a58b

diff --git a/src/common/filter/filter-visitor-generate-bytecode.c b/src/common/filter/filter-visitor-generate-bytecode.c
new file mode 100644
index 000000000..699273c3d
--- /dev/null
+++ b/src/common/filter/filter-visitor-generate-bytecode.c
@@ -0,0 +1,830 @@
+/*
+ * filter-visitor-generate-bytecode.c
+ *
+ * LTTng filter bytecode generation
+ *
+ * Copyright 2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * SPDX-License-Identifier: LGPL-2.1-only
+ *
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <common/align.h>
+#include <common/compat/string.h>
+
+#include "filter-bytecode.h"
+#include "filter-ir.h"
+#include "filter-ast.h"
+
+#include <common/macros.h>
+
+#ifndef max_t
+#define max_t(type, a, b)	((type) ((a) > (b) ? (a) : (b)))
+#endif
+
+#define INIT_ALLOC_SIZE		4
+
+static
+int recursive_visit_gen_bytecode(struct filter_parser_ctx *ctx,
+		struct ir_op *node);
+
+static inline int get_count_order(unsigned int count)
+{
+	int order;
+
+	order = lttng_fls(count) - 1;
+	if (count & (count - 1))
+		order++;
+	return order;
+}
+
+static
+int bytecode_init(struct lttng_filter_bytecode_alloc **fb)
+{
+	uint32_t alloc_len;
+
+	alloc_len = sizeof(struct lttng_filter_bytecode_alloc) + INIT_ALLOC_SIZE;
+	*fb = calloc(alloc_len, 1);
+	if (!*fb) {
+		return -ENOMEM;
+	} else {
+		(*fb)->alloc_len = alloc_len;
+		return 0;
+	}
+}
+
+static
+int32_t bytecode_reserve(struct lttng_filter_bytecode_alloc **fb, uint32_t align, uint32_t len)
+{
+	int32_t ret;
+	uint32_t padding = offset_align((*fb)->b.len, align);
+	uint32_t new_len = (*fb)->b.len + padding + len;
+	uint32_t new_alloc_len = sizeof(struct lttng_filter_bytecode_alloc) + new_len;
+	uint32_t old_alloc_len = (*fb)->alloc_len;
+
+	if (new_len > LTTNG_FILTER_MAX_LEN)
+		return -EINVAL;
+
+	if (new_alloc_len > old_alloc_len) {
+		struct lttng_filter_bytecode_alloc *newptr;
+
+		new_alloc_len =
+			max_t(uint32_t, 1U << get_count_order(new_alloc_len), old_alloc_len << 1);
+		newptr = realloc(*fb, new_alloc_len);
+		if (!newptr)
+			return -ENOMEM;
+		*fb = newptr;
+		/* We zero directly the memory from start of allocation. */
+		memset(&((char *) *fb)[old_alloc_len], 0, new_alloc_len - old_alloc_len);
+		(*fb)->alloc_len = new_alloc_len;
+	}
+	(*fb)->b.len += padding;
+	ret = (*fb)->b.len;
+	(*fb)->b.len += len;
+	return ret;
+}
+
+static
+int bytecode_push(struct lttng_filter_bytecode_alloc **fb, const void *data,
+		uint32_t align, uint32_t len)
+{
+	int32_t offset;
+
+	offset = bytecode_reserve(fb, align, len);
+	if (offset < 0)
+		return offset;
+	memcpy(&(*fb)->b.data[offset], data, len);
+	return 0;
+}
+
+static
+int bytecode_push_logical(struct lttng_filter_bytecode_alloc **fb,
+		struct logical_op *data,
+		uint32_t align, uint32_t len,
+		uint16_t *skip_offset)
+{
+	int32_t offset;
+
+	offset = bytecode_reserve(fb, align, len);
+	if (offset < 0)
+		return offset;
+	memcpy(&(*fb)->b.data[offset], data, len);
+	*skip_offset =
+		(void *) &((struct logical_op *) &(*fb)->b.data[offset])->skip_offset
+			- (void *) &(*fb)->b.data[0];
+	return 0;
+}
+
+static
+int bytecode_patch(struct lttng_filter_bytecode_alloc **fb,
+		const void *data,
+		uint16_t offset,
+		uint32_t len)
+{
+	if (offset >= (*fb)->b.len) {
+		return -EINVAL;
+	}
+	memcpy(&(*fb)->b.data[offset], data, len);
+	return 0;
+}
+
+static
+int visit_node_root(struct filter_parser_ctx *ctx, struct ir_op *node)
+{
+	int ret;
+	struct return_op insn;
+
+	/* Visit child */
+	ret = recursive_visit_gen_bytecode(ctx, node->u.root.child);
+	if (ret)
+		return ret;
+
+	/* Generate end of bytecode instruction */
+	insn.op = FILTER_OP_RETURN;
+	return bytecode_push(&ctx->bytecode, &insn, 1, sizeof(insn));
+}
+
+static
+int append_str(char **s, const char *append)
+{
+	char *old = *s;
+	char *new;
+	size_t oldlen = (old == NULL) ? 0 : strlen(old);
+	size_t appendlen = strlen(append);
+
+	new = calloc(oldlen + appendlen + 1, 1);
+	if (!new) {
+		return -ENOMEM;
+	}
+	if (oldlen) {
+		strcpy(new, old);
+	}
+	strcat(new, append);
+	*s = new;
+	free(old);
+	return 0;
+}
+
+/*
+ * 1: match
+ * 0: no match
+ * < 0: error
+ */
+static
+int load_expression_legacy_match(const struct ir_load_expression *exp,
+		enum filter_op *op_type,
+		char **symbol)
+{
+	const struct ir_load_expression_op *op;
+	bool need_dot = false;
+
+	op = exp->child;
+	switch (op->type) {
+	case IR_LOAD_EXPRESSION_GET_CONTEXT_ROOT:
+		*op_type = FILTER_OP_GET_CONTEXT_REF;
+		if (append_str(symbol, "$ctx.")) {
+			return -ENOMEM;
+		}
+		need_dot = false;
+		break;
+	case IR_LOAD_EXPRESSION_GET_APP_CONTEXT_ROOT:
+		*op_type = FILTER_OP_GET_CONTEXT_REF;
+		if (append_str(symbol, "$app.")) {
+			return -ENOMEM;
+		}
+		need_dot = false;
+		break;
+	case IR_LOAD_EXPRESSION_GET_PAYLOAD_ROOT:
+		*op_type = FILTER_OP_LOAD_FIELD_REF;
+		need_dot = false;
+		break;
+
+	case IR_LOAD_EXPRESSION_GET_SYMBOL:
+	case IR_LOAD_EXPRESSION_GET_INDEX:
+	case IR_LOAD_EXPRESSION_LOAD_FIELD:
+	default:
+		return 0;	/* no match */
+	}
+
+	for (;;) {
+		op = op->next;
+		if (!op) {
+			return 0;	/* no match */
+		}
+		switch (op->type) {
+		case IR_LOAD_EXPRESSION_LOAD_FIELD:
+			goto end;
+		case IR_LOAD_EXPRESSION_GET_SYMBOL:
+			if (need_dot && append_str(symbol, ".")) {
+				return -ENOMEM;
+			}
+			if (append_str(symbol, op->u.symbol)) {
+				return -ENOMEM;
+			}
+			break;
+		default:
+			return 0;	 /* no match */
+		}
+		need_dot = true;
+	}
+end:
+	return 1;	/* Legacy match */
+}
+
+/*
+ * 1: legacy match
+ * 0: no legacy match
+ * < 0: error
+ */
+static
+int visit_node_load_expression_legacy(struct filter_parser_ctx *ctx,
+		const struct ir_load_expression *exp,
+		const struct ir_load_expression_op *op)
+{
+	struct load_op *insn = NULL;
+	uint32_t insn_len = sizeof(struct load_op)
+		+ sizeof(struct field_ref);
+	struct field_ref ref_offset;
+	uint32_t reloc_offset_u32;
+	uint16_t reloc_offset;
+	enum filter_op op_type;
+	char *symbol = NULL;
+	int ret;
+
+	ret = load_expression_legacy_match(exp, &op_type, &symbol);
+	if (ret <= 0) {
+		goto end;
+	}
+	insn = calloc(insn_len, 1);
+	if (!insn) {
+		ret = -ENOMEM;
+		goto end;
+	}
+	insn->op = op_type;
+	ref_offset.offset = (uint16_t) -1U;
+	memcpy(insn->data, &ref_offset, sizeof(ref_offset));
+	/* reloc_offset points to struct load_op */
+	reloc_offset_u32 = bytecode_get_len(&ctx->bytecode->b);
+	if (reloc_offset_u32 > LTTNG_FILTER_MAX_LEN - 1) {
+		ret = -EINVAL;
+		goto end;
+	}
+	reloc_offset = (uint16_t) reloc_offset_u32;
+	ret = bytecode_push(&ctx->bytecode, insn, 1, insn_len);
+	if (ret) {
+		goto end;
+	}
+	/* append reloc */
+	ret = bytecode_push(&ctx->bytecode_reloc, &reloc_offset,
+				1, sizeof(reloc_offset));
+	if (ret) {
+		goto end;
+	}
+	ret = bytecode_push(&ctx->bytecode_reloc, symbol,
+				1, strlen(symbol) + 1);
+	if (ret) {
+		goto end;
+	}
+	ret = 1;	/* legacy */
+end:
+	free(insn);
+	free(symbol);
+	return ret;
+}
+
+static
+int visit_node_load_expression(struct filter_parser_ctx *ctx,
+		const struct ir_op *node)
+{
+	struct ir_load_expression *exp;
+	struct ir_load_expression_op *op;
+	int ret;
+
+	exp = node->u.load.u.expression;
+	if (!exp) {
+		return -EINVAL;
+	}
+	op = exp->child;
+	if (!op) {
+		return -EINVAL;
+	}
+
+	/*
+	 * TODO: if we remove legacy load for application contexts, we
+	 * need to update session bytecode parser as well.
+	 */
+	ret = visit_node_load_expression_legacy(ctx, exp, op);
+	if (ret < 0) {
+		return ret;
+	}
+	if (ret > 0) {
+		return 0;	/* legacy */
+	}
+
+	for (; op != NULL; op = op->next) {
+		switch (op->type) {
+		case IR_LOAD_EXPRESSION_GET_CONTEXT_ROOT:
+		{
+			struct load_op *insn;
+			uint32_t insn_len = sizeof(struct load_op);
+			int ret;
+
+			insn = calloc(insn_len, 1);
+			if (!insn)
+				return -ENOMEM;
+			insn->op = FILTER_OP_GET_CONTEXT_ROOT;
+			ret = bytecode_push(&ctx->bytecode, insn, 1, insn_len);
+			free(insn);
+			if (ret) {
+				return ret;
+			}
+			break;
+		}
+		case IR_LOAD_EXPRESSION_GET_APP_CONTEXT_ROOT:
+		{
+			struct load_op *insn;
+			uint32_t insn_len = sizeof(struct load_op);
+			int ret;
+
+			insn = calloc(insn_len, 1);
+			if (!insn)
+				return -ENOMEM;
+			insn->op = FILTER_OP_GET_APP_CONTEXT_ROOT;
+			ret = bytecode_push(&ctx->bytecode, insn, 1, insn_len);
+			free(insn);
+			if (ret) {
+				return ret;
+			}
+			break;
+		}
+		case IR_LOAD_EXPRESSION_GET_PAYLOAD_ROOT:
+		{
+			struct load_op *insn;
+			uint32_t insn_len = sizeof(struct load_op);
+			int ret;
+
+			insn = calloc(insn_len, 1);
+			if (!insn)
+				return -ENOMEM;
+			insn->op = FILTER_OP_GET_PAYLOAD_ROOT;
+			ret = bytecode_push(&ctx->bytecode, insn, 1, insn_len);
+			free(insn);
+			if (ret) {
+				return ret;
+			}
+			break;
+		}
+		case IR_LOAD_EXPRESSION_GET_SYMBOL:
+		{
+			struct load_op *insn;
+			uint32_t insn_len = sizeof(struct load_op)
+				+ sizeof(struct get_symbol);
+			struct get_symbol symbol_offset;
+			uint32_t reloc_offset_u32;
+			uint16_t reloc_offset;
+			uint32_t bytecode_reloc_offset_u32;
+			int ret;
+
+			insn = calloc(insn_len, 1);
+			if (!insn)
+				return -ENOMEM;
+			insn->op = FILTER_OP_GET_SYMBOL;
+			bytecode_reloc_offset_u32 =
+					bytecode_get_len(&ctx->bytecode_reloc->b)
+					+ sizeof(reloc_offset);
+			symbol_offset.offset =
+					(uint16_t) bytecode_reloc_offset_u32;
+			memcpy(insn->data, &symbol_offset,
+					sizeof(symbol_offset));
+			/* reloc_offset points to struct load_op */
+			reloc_offset_u32 = bytecode_get_len(&ctx->bytecode->b);
+			if (reloc_offset_u32 > LTTNG_FILTER_MAX_LEN - 1) {
+				free(insn);
+				return -EINVAL;
+			}
+			reloc_offset = (uint16_t) reloc_offset_u32;
+			ret = bytecode_push(&ctx->bytecode, insn, 1, insn_len);
+			if (ret) {
+				free(insn);
+				return ret;
+			}
+			/* append reloc */
+			ret = bytecode_push(&ctx->bytecode_reloc, &reloc_offset,
+					1, sizeof(reloc_offset));
+			if (ret) {
+				free(insn);
+				return ret;
+			}
+			ret = bytecode_push(&ctx->bytecode_reloc,
+					op->u.symbol,
+					1, strlen(op->u.symbol) + 1);
+			free(insn);
+			if (ret) {
+				return ret;
+			}
+			break;
+		}
+		case IR_LOAD_EXPRESSION_GET_INDEX:
+		{
+			struct load_op *insn;
+			uint32_t insn_len = sizeof(struct load_op)
+				+ sizeof(struct get_index_u64);
+			struct get_index_u64 index;
+			int ret;
+
+			insn = calloc(insn_len, 1);
+			if (!insn)
+				return -ENOMEM;
+			insn->op = FILTER_OP_GET_INDEX_U64;
+			index.index = op->u.index;
+			memcpy(insn->data, &index, sizeof(index));
+			ret = bytecode_push(&ctx->bytecode, insn, 1, insn_len);
+			free(insn);
+			if (ret) {
+				return ret;
+			}
+			break;
+		}
+		case IR_LOAD_EXPRESSION_LOAD_FIELD:
+		{
+			struct load_op *insn;
+			uint32_t insn_len = sizeof(struct load_op);
+			int ret;
+
+			insn = calloc(insn_len, 1);
+			if (!insn)
+				return -ENOMEM;
+			insn->op = FILTER_OP_LOAD_FIELD;
+			ret = bytecode_push(&ctx->bytecode, insn, 1, insn_len);
+			free(insn);
+			if (ret) {
+				return ret;
+			}
+			break;
+		}
+		}
+	}
+	return 0;
+}
+
+static
+int visit_node_load(struct filter_parser_ctx *ctx, struct ir_op *node)
+{
+	int ret;
+
+	switch (node->data_type) {
+	case IR_DATA_UNKNOWN:
+	default:
+		fprintf(stderr, "[error] Unknown data type in %s\n",
+			__func__);
+		return -EINVAL;
+
+	case IR_DATA_STRING:
+	{
+		struct load_op *insn;
+		uint32_t insn_len = sizeof(struct load_op)
+			+ strlen(node->u.load.u.string.value) + 1;
+
+		insn = calloc(insn_len, 1);
+		if (!insn)
+			return -ENOMEM;
+
+		switch (node->u.load.u.string.type) {
+		case IR_LOAD_STRING_TYPE_GLOB_STAR:
+			/*
+			 * We explicitly tell the interpreter here that
+			 * this load is a full star globbing pattern so
+			 * that the appropriate matching function can be
+			 * called. Also, see comment below.
+			 */
+			insn->op = FILTER_OP_LOAD_STAR_GLOB_STRING;
+			break;
+		default:
+			/*
+			 * This is the "legacy" string, which includes
+			 * star globbing patterns with a star only at
+			 * the end. Both "plain" and "star at the end"
+			 * literal strings are handled at the same place
+			 * by the tracer's filter bytecode interpreter,
+			 * whereas full star globbing patterns (stars
+			 * can be anywhere in the string) is a special
+			 * case.
+			 */
+			insn->op = FILTER_OP_LOAD_STRING;
+			break;
+		}
+
+		strcpy(insn->data, node->u.load.u.string.value);
+		ret = bytecode_push(&ctx->bytecode, insn, 1, insn_len);
+		free(insn);
+		return ret;
+	}
+	case IR_DATA_NUMERIC:
+	{
+		struct load_op *insn;
+		uint32_t insn_len = sizeof(struct load_op)
+			+ sizeof(struct literal_numeric);
+
+		insn = calloc(insn_len, 1);
+		if (!insn)
+			return -ENOMEM;
+		insn->op = FILTER_OP_LOAD_S64;
+		memcpy(insn->data, &node->u.load.u.num, sizeof(int64_t));
+		ret = bytecode_push(&ctx->bytecode, insn, 1, insn_len);
+		free(insn);
+		return ret;
+	}
+	case IR_DATA_FLOAT:
+	{
+		struct load_op *insn;
+		uint32_t insn_len = sizeof(struct load_op)
+			+ sizeof(struct literal_double);
+
+		insn = calloc(insn_len, 1);
+		if (!insn)
+			return -ENOMEM;
+		insn->op = FILTER_OP_LOAD_DOUBLE;
+		memcpy(insn->data, &node->u.load.u.flt, sizeof(double));
+		ret = bytecode_push(&ctx->bytecode, insn, 1, insn_len);
+		free(insn);
+		return ret;
+	}
+	case IR_DATA_EXPRESSION:
+		return visit_node_load_expression(ctx, node);
+	}
+}
+
+static
+int visit_node_unary(struct filter_parser_ctx *ctx, struct ir_op *node)
+{
+	int ret;
+	struct unary_op insn;
+
+	/* Visit child */
+	ret = recursive_visit_gen_bytecode(ctx, node->u.unary.child);
+	if (ret)
+		return ret;
+
+	/* Generate end of bytecode instruction */
+	switch (node->u.unary.type) {
+	case AST_UNARY_UNKNOWN:
+	default:
+		fprintf(stderr, "[error] Unknown unary node type in %s\n",
+			__func__);
+		return -EINVAL;
+	case AST_UNARY_PLUS:
+		/* Nothing to do. */
+		return 0;
+	case AST_UNARY_MINUS:
+		insn.op = FILTER_OP_UNARY_MINUS;
+		return bytecode_push(&ctx->bytecode, &insn, 1, sizeof(insn));
+	case AST_UNARY_NOT:
+		insn.op = FILTER_OP_UNARY_NOT;
+		return bytecode_push(&ctx->bytecode, &insn, 1, sizeof(insn));
+	case AST_UNARY_BIT_NOT:
+		insn.op = FILTER_OP_UNARY_BIT_NOT;
+		return bytecode_push(&ctx->bytecode, &insn, 1, sizeof(insn));
+	}
+}
+
+/*
+ * Binary comparator nesting is disallowed. This allows fitting into
+ * only 2 registers.
+ */
+static
+int visit_node_binary(struct filter_parser_ctx *ctx, struct ir_op *node)
+{
+	int ret;
+	struct binary_op insn;
+
+	/* Visit child */
+	ret = recursive_visit_gen_bytecode(ctx, node->u.binary.left);
+	if (ret)
+		return ret;
+	ret = recursive_visit_gen_bytecode(ctx, node->u.binary.right);
+	if (ret)
+		return ret;
+
+	switch (node->u.binary.type) {
+	case AST_OP_UNKNOWN:
+	default:
+		fprintf(stderr, "[error] Unknown unary node type in %s\n",
+			__func__);
+		return -EINVAL;
+
+	case AST_OP_AND:
+	case AST_OP_OR:
+		fprintf(stderr, "[error] Unexpected logical node type in %s\n",
+			__func__);
+		return -EINVAL;
+
+	case AST_OP_MUL:
+		insn.op = FILTER_OP_MUL;
+		break;
+	case AST_OP_DIV:
+		insn.op = FILTER_OP_DIV;
+		break;
+	case AST_OP_MOD:
+		insn.op = FILTER_OP_MOD;
+		break;
+	case AST_OP_PLUS:
+		insn.op = FILTER_OP_PLUS;
+		break;
+	case AST_OP_MINUS:
+		insn.op = FILTER_OP_MINUS;
+		break;
+	case AST_OP_BIT_RSHIFT:
+		insn.op = FILTER_OP_BIT_RSHIFT;
+		break;
+	case AST_OP_BIT_LSHIFT:
+		insn.op = FILTER_OP_BIT_LSHIFT;
+		break;
+	case AST_OP_BIT_AND:
+		insn.op = FILTER_OP_BIT_AND;
+		break;
+	case AST_OP_BIT_OR:
+		insn.op = FILTER_OP_BIT_OR;
+		break;
+	case AST_OP_BIT_XOR:
+		insn.op = FILTER_OP_BIT_XOR;
+		break;
+
+	case AST_OP_EQ:
+		insn.op = FILTER_OP_EQ;
+		break;
+	case AST_OP_NE:
+		insn.op = FILTER_OP_NE;
+		break;
+	case AST_OP_GT:
+		insn.op = FILTER_OP_GT;
+		break;
+	case AST_OP_LT:
+		insn.op = FILTER_OP_LT;
+		break;
+	case AST_OP_GE:
+		insn.op = FILTER_OP_GE;
+		break;
+	case AST_OP_LE:
+		insn.op = FILTER_OP_LE;
+		break;
+	}
+	return bytecode_push(&ctx->bytecode, &insn, 1, sizeof(insn));
+}
+
+/*
+ * A logical op always return a s64 (1 or 0).
+ */
+static
+int visit_node_logical(struct filter_parser_ctx *ctx, struct ir_op *node)
+{
+	int ret;
+	struct logical_op insn;
+	uint16_t skip_offset_loc;
+	uint16_t target_loc;
+
+	/* Visit left child */
+	ret = recursive_visit_gen_bytecode(ctx, node->u.binary.left);
+	if (ret)
+		return ret;
+	/* Cast to s64 if float or field ref */
+	if ((node->u.binary.left->data_type == IR_DATA_FIELD_REF
+				|| node->u.binary.left->data_type == IR_DATA_GET_CONTEXT_REF
+				|| node->u.binary.left->data_type == IR_DATA_EXPRESSION)
+			|| node->u.binary.left->data_type == IR_DATA_FLOAT) {
+		struct cast_op cast_insn;
+
+		if (node->u.binary.left->data_type == IR_DATA_FIELD_REF
+				|| node->u.binary.left->data_type == IR_DATA_GET_CONTEXT_REF
+				|| node->u.binary.left->data_type == IR_DATA_EXPRESSION) {
+			cast_insn.op = FILTER_OP_CAST_TO_S64;
+		} else {
+			cast_insn.op = FILTER_OP_CAST_DOUBLE_TO_S64;
+		}
+		ret = bytecode_push(&ctx->bytecode, &cast_insn,
+					1, sizeof(cast_insn));
+		if (ret)
+			return ret;
+	}
+	switch (node->u.logical.type) {
+	default:
+		fprintf(stderr, "[error] Unknown node type in %s\n",
+			__func__);
+		return -EINVAL;
+
+	case AST_OP_AND:
+		insn.op = FILTER_OP_AND;
+		break;
+	case AST_OP_OR:
+		insn.op = FILTER_OP_OR;
+		break;
+	}
+	insn.skip_offset = (uint16_t) -1UL;	/* Temporary */
+	ret = bytecode_push_logical(&ctx->bytecode, &insn, 1, sizeof(insn),
+			&skip_offset_loc);
+	if (ret)
+		return ret;
+	/* Visit right child */
+	ret = recursive_visit_gen_bytecode(ctx, node->u.binary.right);
+	if (ret)
+		return ret;
+	/* Cast to s64 if float or field ref */
+	if ((node->u.binary.right->data_type == IR_DATA_FIELD_REF
+				|| node->u.binary.right->data_type == IR_DATA_GET_CONTEXT_REF
+				|| node->u.binary.right->data_type == IR_DATA_EXPRESSION)
+			|| node->u.binary.right->data_type == IR_DATA_FLOAT) {
+		struct cast_op cast_insn;
+
+		if (node->u.binary.right->data_type == IR_DATA_FIELD_REF
+				|| node->u.binary.right->data_type == IR_DATA_GET_CONTEXT_REF
+				|| node->u.binary.right->data_type == IR_DATA_EXPRESSION) {
+			cast_insn.op = FILTER_OP_CAST_TO_S64;
+		} else {
+			cast_insn.op = FILTER_OP_CAST_DOUBLE_TO_S64;
+		}
+		ret = bytecode_push(&ctx->bytecode, &cast_insn,
+					1, sizeof(cast_insn));
+		if (ret)
+			return ret;
+	}
+	/* We now know where the logical op can skip. */
+	target_loc = (uint16_t) bytecode_get_len(&ctx->bytecode->b);
+	ret = bytecode_patch(&ctx->bytecode,
+			&target_loc,			/* Offset to jump to */
+			skip_offset_loc,		/* Where to patch */
+			sizeof(uint16_t));
+	return ret;
+}
+
+/*
+ * Postorder traversal of the tree. We need the children result before
+ * we can evaluate the parent.
+ */
+static
+int recursive_visit_gen_bytecode(struct filter_parser_ctx *ctx,
+		struct ir_op *node)
+{
+	switch (node->op) {
+	case IR_OP_UNKNOWN:
+	default:
+		fprintf(stderr, "[error] Unknown node type in %s\n",
+			__func__);
+		return -EINVAL;
+
+	case IR_OP_ROOT:
+		return visit_node_root(ctx, node);
+	case IR_OP_LOAD:
+		return visit_node_load(ctx, node);
+	case IR_OP_UNARY:
+		return visit_node_unary(ctx, node);
+	case IR_OP_BINARY:
+		return visit_node_binary(ctx, node);
+	case IR_OP_LOGICAL:
+		return visit_node_logical(ctx, node);
+	}
+}
+
+LTTNG_HIDDEN
+void filter_bytecode_free(struct filter_parser_ctx *ctx)
+{
+	if (!ctx) {
+		return;
+	}
+
+	if (ctx->bytecode) {
+		free(ctx->bytecode);
+		ctx->bytecode = NULL;
+	}
+
+	if (ctx->bytecode_reloc) {
+		free(ctx->bytecode_reloc);
+		ctx->bytecode_reloc = NULL;
+	}
+}
+
+LTTNG_HIDDEN
+int filter_visitor_bytecode_generate(struct filter_parser_ctx *ctx)
+{
+	int ret;
+
+	ret = bytecode_init(&ctx->bytecode);
+	if (ret)
+		return ret;
+	ret = bytecode_init(&ctx->bytecode_reloc);
+	if (ret)
+		goto error;
+	ret = recursive_visit_gen_bytecode(ctx, ctx->ir_root);
+	if (ret)
+		goto error;
+
+	/* Finally, append symbol table to bytecode */
+	ctx->bytecode->b.reloc_table_offset = bytecode_get_len(&ctx->bytecode->b);
+	return bytecode_push(&ctx->bytecode, ctx->bytecode_reloc->b.data,
+			1, bytecode_get_len(&ctx->bytecode_reloc->b));
+
+error:
+	filter_bytecode_free(ctx);
+	return ret;
+}