From 93c591bb3a90753ce66197f2c1e41c8ef554506f Mon Sep 17 00:00:00 2001
From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Mon, 25 Sep 2017 11:37:28 -0400
Subject: [PATCH] Filter: add FILTER_OP_RETURN_S64 instruction

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---
 liblttng-ust/filter-bytecode.h          |  2 ++
 liblttng-ust/lttng-filter-interpreter.c |  8 ++++++++
 liblttng-ust/lttng-filter-specialize.c  | 11 +++++++++++
 liblttng-ust/lttng-filter-validator.c   | 23 +++++++++++++++++++++++
 liblttng-ust/lttng-filter.c             |  2 ++
 5 files changed, 46 insertions(+)

diff --git a/liblttng-ust/filter-bytecode.h b/liblttng-ust/filter-bytecode.h
index f937324d..9a2d4c0a 100644
--- a/liblttng-ust/filter-bytecode.h
+++ b/liblttng-ust/filter-bytecode.h
@@ -206,6 +206,8 @@ enum filter_op {
 
 	FILTER_OP_UNARY_BIT_NOT			= 98,
 
+	FILTER_OP_RETURN_S64			= 99,
+
 	NR_FILTER_OPS,
 };
 
diff --git a/liblttng-ust/lttng-filter-interpreter.c b/liblttng-ust/lttng-filter-interpreter.c
index 753880c3..59bc72cd 100644
--- a/liblttng-ust/lttng-filter-interpreter.c
+++ b/liblttng-ust/lttng-filter-interpreter.c
@@ -742,6 +742,8 @@ uint64_t lttng_filter_interpret_bytecode(void *filter_data,
 		[ FILTER_OP_LOAD_FIELD_DOUBLE ] = &&LABEL_FILTER_OP_LOAD_FIELD_DOUBLE,
 
 		[ FILTER_OP_UNARY_BIT_NOT ] = &&LABEL_FILTER_OP_UNARY_BIT_NOT,
+
+		[ FILTER_OP_RETURN_S64 ] = &&LABEL_FILTER_OP_RETURN_S64,
 	};
 #endif /* #ifndef INTERPRETER_USE_SWITCH */
 
@@ -774,6 +776,12 @@ uint64_t lttng_filter_interpret_bytecode(void *filter_data,
 			ret = 0;
 			goto end;
 
+		OP(FILTER_OP_RETURN_S64):
+			/* LTTNG_FILTER_DISCARD  or LTTNG_FILTER_RECORD_FLAG */
+			retval = !!estack_ax_v;
+			ret = 0;
+			goto end;
+
 		/* binary */
 		OP(FILTER_OP_MUL):
 		OP(FILTER_OP_DIV):
diff --git a/liblttng-ust/lttng-filter-specialize.c b/liblttng-ust/lttng-filter-specialize.c
index 6de25047..1ade2883 100644
--- a/liblttng-ust/lttng-filter-specialize.c
+++ b/liblttng-ust/lttng-filter-specialize.c
@@ -621,6 +621,17 @@ int lttng_filter_specialize_bytecode(struct lttng_event *event,
 			goto end;
 
 		case FILTER_OP_RETURN:
+			if (vstack_ax(stack)->type == REG_S64)
+				*(filter_opcode_t *) pc = FILTER_OP_RETURN_S64;
+			ret = 0;
+			goto end;
+
+		case FILTER_OP_RETURN_S64:
+			if (vstack_ax(stack)->type != REG_S64) {
+				ERR("Unexpected register type\n");
+				ret = -EINVAL;
+				goto end;
+			}
 			ret = 0;
 			goto end;
 
diff --git a/liblttng-ust/lttng-filter-validator.c b/liblttng-ust/lttng-filter-validator.c
index 4fe8e893..92455c80 100644
--- a/liblttng-ust/lttng-filter-validator.c
+++ b/liblttng-ust/lttng-filter-validator.c
@@ -296,6 +296,7 @@ int bytecode_validate_overflow(struct bytecode_runtime *bytecode,
 	}
 
 	case FILTER_OP_RETURN:
+	case FILTER_OP_RETURN_S64:
 	{
 		if (unlikely(pc + sizeof(struct return_op)
 				> start_pc + bytecode->len)) {
@@ -578,6 +579,7 @@ int validate_instruction_context(struct bytecode_runtime *bytecode,
 	}
 
 	case FILTER_OP_RETURN:
+	case FILTER_OP_RETURN_S64:
 	{
 		goto end;
 	}
@@ -1255,6 +1257,27 @@ int exec_insn(struct bytecode_runtime *bytecode,
 		ret = 0;
 		goto end;
 	}
+	case FILTER_OP_RETURN_S64:
+	{
+		if (!vstack_ax(stack)) {
+			ERR("Empty stack\n");
+			ret = -EINVAL;
+			goto end;
+		}
+		switch (vstack_ax(stack)->type) {
+		case REG_S64:
+			break;
+		default:
+		case REG_UNKNOWN:
+			ERR("Unexpected register type %d at end of bytecode\n",
+				(int) vstack_ax(stack)->type);
+			ret = -EINVAL;
+			goto end;
+		}
+
+		ret = 0;
+		goto end;
+	}
 
 	/* binary */
 	case FILTER_OP_MUL:
diff --git a/liblttng-ust/lttng-filter.c b/liblttng-ust/lttng-filter.c
index b7f058a8..d52658ae 100644
--- a/liblttng-ust/lttng-filter.c
+++ b/liblttng-ust/lttng-filter.c
@@ -170,6 +170,8 @@ static const char *opnames[] = {
 	[ FILTER_OP_LOAD_FIELD_DOUBLE ] = "LOAD_FIELD_DOUBLE",
 
 	[ FILTER_OP_UNARY_BIT_NOT ] = "UNARY_BIT_NOT",
+
+	[ FILTER_OP_RETURN_S64 ] = "RETURN_S64",
 };
 
 const char *print_op(enum filter_op op)
-- 
2.34.1