From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Mon, 19 Apr 2021 14:07:08 +0000 (-0400)
Subject: ust-events.h API const-ness
X-Git-Tag: v2.13.0-rc1~82
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=3d33ca1d93088e049c36fc0f417d130bc66b2231;p=lttng-ust.git

ust-events.h API const-ness

Ensure ust-events.h definitions, fields, and arguments referring to
const arrays of pointers are const.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I9b1173221c2cfd2d574c300233e15a3fc0e72bce
---

diff --git a/include/lttng/ust-events.h b/include/lttng/ust-events.h
index 2b035d8f..cf1045bb 100644
--- a/include/lttng/ust-events.h
+++ b/include/lttng/ust-events.h
@@ -203,8 +203,8 @@ struct lttng_ust_type_struct {
 	struct lttng_ust_type_common parent;
 	uint32_t struct_size;
 	unsigned int nr_fields;
-	const struct lttng_ust_event_field **fields;	/* Array of pointers to fields. */
-	unsigned int alignment;		/* Minimum alignment for this type. */
+	const struct lttng_ust_event_field * const *fields;	/* Array of pointers to fields. */
+	unsigned int alignment;					/* Minimum alignment for this type. */
 };
 
 /*
@@ -223,7 +223,7 @@ struct lttng_ust_enum_desc {
 	uint32_t struct_size;
 
 	const char *name;
-	const struct lttng_ust_enum_entry **entries;
+	const struct lttng_ust_enum_entry * const *entries;
 	unsigned int nr_entries;
 
 	/* End of base ABI. Fields below should be used after checking struct_size. */
@@ -268,7 +268,7 @@ struct lttng_ust_event_desc {
 	const char *event_name;
 	const struct lttng_ust_probe_desc *probe_desc;
 	void (*probe_callback)(void);
-	const struct lttng_ust_event_field **fields;	/* event payload */
+	const struct lttng_ust_event_field * const *fields;	/* event payload */
 	unsigned int nr_fields;
 	const int **loglevel;
 	const char *signature;				/* Argument types/names received */
@@ -290,7 +290,7 @@ struct lttng_ust_probe_desc {
 	uint32_t struct_size;			/* Size of this structure. */
 
 	const char *provider_name;
-	const struct lttng_ust_event_desc **event_desc;
+	const struct lttng_ust_event_desc * const *event_desc;
 	unsigned int nr_events;
 	uint32_t major;
 	uint32_t minor;
diff --git a/include/lttng/ust-tracepoint-event.h b/include/lttng/ust-tracepoint-event.h
index c50047d0..e663e839 100644
--- a/include/lttng/ust-tracepoint-event.h
+++ b/include/lttng/ust-tracepoint-event.h
@@ -203,7 +203,7 @@ void __event_template_proto___##_provider##___##_name(_TP_ARGS_DATA_PROTO(_args)
 
 #undef TRACEPOINT_ENUM
 #define TRACEPOINT_ENUM(_provider, _name, _values)			\
-	const struct lttng_ust_enum_entry *__enum_values__##_provider##_##_name[] = { \
+	const struct lttng_ust_enum_entry * const __enum_values__##_provider##_##_name[] = { \
 		_values							\
 		ctf_enum_value("", 0)	/* Dummy, 0-len array forbidden by C99. */ \
 	};
@@ -362,7 +362,7 @@ void __event_template_proto___##_provider##___##_name(_TP_ARGS_DATA_PROTO(_args)
 
 #undef _TRACEPOINT_EVENT_CLASS
 #define _TRACEPOINT_EVENT_CLASS(_provider, _name, _args, _fields)		   	     \
-	static const struct lttng_ust_event_field *__event_fields___##_provider##___##_name[] = { \
+	static const struct lttng_ust_event_field * const __event_fields___##_provider##___##_name[] = { \
 		_fields									     \
 		ctf_integer(int, dummy, 0)	/* Dummy, C99 forbids 0-len array. */	     \
 	};
@@ -972,10 +972,10 @@ static const char __tp_event_signature___##_provider##___##_name[] = 	\
 #endif
 
 #undef TRACEPOINT_LOGLEVEL
-#define TRACEPOINT_LOGLEVEL(__provider, __name, __loglevel)		   \
-static const int _loglevel_value___##__provider##___##__name = __loglevel; \
-LTTNG_UST_TP_EXTERN_C const int *_loglevel___##__provider##___##__name	   \
-		__attribute__((visibility("hidden"))) =			   \
+#define TRACEPOINT_LOGLEVEL(__provider, __name, __loglevel)		   	\
+static const int _loglevel_value___##__provider##___##__name = __loglevel; 	\
+LTTNG_UST_TP_EXTERN_C const int * const _loglevel___##__provider##___##__name	\
+		__attribute__((visibility("hidden"))) =				\
 		&_loglevel_value___##__provider##___##__name;
 
 #include TRACEPOINT_INCLUDE
@@ -1005,7 +1005,7 @@ LTTNG_UST_TP_EXTERN_C const int *_loglevel___##__provider##___##__name	   \
 
 #undef TRACEPOINT_MODEL_EMF_URI
 #define TRACEPOINT_MODEL_EMF_URI(__provider, __name, __uri)		   \
-LTTNG_UST_TP_EXTERN_C const char *_model_emf_uri___##__provider##___##__name   \
+LTTNG_UST_TP_EXTERN_C const char * const _model_emf_uri___##__provider##___##__name   \
 		__attribute__((visibility("hidden"))) = __uri;		   \
 
 #include TRACEPOINT_INCLUDE
@@ -1029,8 +1029,14 @@ extern const struct lttng_ust_probe_desc _TP_COMBINE_TOKENS(__probe_desc___, TRA
  * Stage 7.1 of tracepoint event generation.
  *
  * Create events description structures. We use a weakref because
- * loglevels are optional. If not declared, the event will point to the
+ * loglevels are optional. If not declared, the event will point to
  * a loglevel that contains NULL.
+ *
+ * C++ requires that const objects have a user-declared default
+ * constructor. However, in both C++ and C, weakref cannot be
+ * initialized because it causes the weakref attribute to be ignored.
+ * Therefore, the loglevel and model_emf_uri pointers are not const
+ * to ensure C++ compilers default-initialize them.
  */
 
 /* Reset all macros within TRACEPOINT_EVENT */
@@ -1071,7 +1077,7 @@ static const struct lttng_ust_event_desc __event_desc___##_provider##_##_name =
 #define _TRACEPOINT_EVENT_INSTANCE(_provider, _template, _name, _args)	       \
 	&__event_desc___##_provider##_##_name,
 
-static const struct lttng_ust_event_desc *_TP_COMBINE_TOKENS(__event_desc___, TRACEPOINT_PROVIDER)[] = {
+static const struct lttng_ust_event_desc * const _TP_COMBINE_TOKENS(__event_desc___, TRACEPOINT_PROVIDER)[] = {
 #include TRACEPOINT_INCLUDE
 	NULL,	/* Dummy, C99 forbids 0-len array. */
 };
diff --git a/src/common/dynamic-type.h b/src/common/dynamic-type.h
index 84f55f9a..f918921d 100644
--- a/src/common/dynamic-type.h
+++ b/src/common/dynamic-type.h
@@ -26,7 +26,7 @@ enum lttng_ust_dynamic_type {
 };
 
 int lttng_ust_dynamic_type_choices(size_t *nr_choices,
-		const struct lttng_ust_event_field ***choices)
+		const struct lttng_ust_event_field * const **choices)
 	__attribute__((visibility("hidden")));
 
 const struct lttng_ust_event_field *lttng_ust_dynamic_type_field(int64_t value)
diff --git a/src/common/ustcomm.c b/src/common/ustcomm.c
index 80346ce1..ad6332fd 100644
--- a/src/common/ustcomm.c
+++ b/src/common/ustcomm.c
@@ -37,7 +37,7 @@
 
 static
 ssize_t count_fields_recursive(size_t nr_fields,
-		const struct lttng_ust_event_field **lttng_fields);
+		const struct lttng_ust_event_field * const *lttng_fields);
 static
 int serialize_one_field(struct lttng_ust_session *session,
 		struct ustctl_field *fields, size_t *iter_output,
@@ -46,7 +46,7 @@ static
 int serialize_fields(struct lttng_ust_session *session,
 		struct ustctl_field *ustctl_fields,
 		size_t *iter_output, size_t nr_lttng_fields,
-		const struct lttng_ust_event_field **lttng_fields);
+		const struct lttng_ust_event_field * const *lttng_fields);
 
 /*
  * Human readable error message.
@@ -883,7 +883,7 @@ ssize_t count_one_type(const struct lttng_ust_type_common *lt)
 
 	case lttng_ust_type_dynamic:
 	{
-		const struct lttng_ust_event_field **choices;
+		const struct lttng_ust_event_field * const *choices;
 		size_t nr_choices;
 		int ret;
 
@@ -906,7 +906,7 @@ ssize_t count_one_type(const struct lttng_ust_type_common *lt)
 
 static
 ssize_t count_fields_recursive(size_t nr_fields,
-		const struct lttng_ust_event_field **lttng_fields)
+		const struct lttng_ust_event_field * const *lttng_fields)
 {
 	int i;
 	ssize_t ret, count = 0;
@@ -991,7 +991,7 @@ int serialize_dynamic_type(struct lttng_ust_session *session,
 		struct ustctl_field *fields, size_t *iter_output,
 		const char *field_name)
 {
-	const struct lttng_ust_event_field **choices;
+	const struct lttng_ust_event_field * const *choices;
 	char tag_field_name[LTTNG_UST_ABI_SYM_NAME_LEN];
 	const struct lttng_ust_type_common *tag_type;
 	const struct lttng_ust_event_field *tag_field_generic;
@@ -1256,7 +1256,7 @@ static
 int serialize_fields(struct lttng_ust_session *session,
 		struct ustctl_field *ustctl_fields,
 		size_t *iter_output, size_t nr_lttng_fields,
-		const struct lttng_ust_event_field **lttng_fields)
+		const struct lttng_ust_event_field * const *lttng_fields)
 {
 	int ret;
 	size_t i;
@@ -1275,7 +1275,7 @@ int alloc_serialize_fields(struct lttng_ust_session *session,
 		size_t *_nr_write_fields,
 		struct ustctl_field **ustctl_fields,
 		size_t nr_fields,
-		const struct lttng_ust_event_field **lttng_fields)
+		const struct lttng_ust_event_field * const *lttng_fields)
 {
 	struct ustctl_field *fields;
 	int ret;
@@ -1308,7 +1308,7 @@ error_type:
 static
 int serialize_entries(struct ustctl_enum_entry **_entries,
 		size_t nr_entries,
-		const struct lttng_ust_enum_entry **lttng_entries)
+		const struct lttng_ust_enum_entry * const *lttng_entries)
 {
 	struct ustctl_enum_entry *entries;
 	int i;
@@ -1389,7 +1389,7 @@ int ustcomm_register_event(int sock,
 	int loglevel,
 	const char *signature,		/* event signature (input) */
 	size_t nr_fields,		/* fields */
-	const struct lttng_ust_event_field **lttng_fields,
+	const struct lttng_ust_event_field * const *lttng_fields,
 	const char *model_emf_uri,
 	uint32_t *id)			/* event id (output) */
 {
@@ -1528,7 +1528,7 @@ int ustcomm_register_enum(int sock,
 	int session_objd,		/* session descriptor */
 	const char *enum_name,		/* enum name (input) */
 	size_t nr_entries,		/* entries */
-	const struct lttng_ust_enum_entry **lttng_entries,
+	const struct lttng_ust_enum_entry * const *lttng_entries,
 	uint64_t *id)
 {
 	ssize_t len;
diff --git a/src/common/ustcomm.h b/src/common/ustcomm.h
index dac9aaed..b4b7fb2c 100644
--- a/src/common/ustcomm.h
+++ b/src/common/ustcomm.h
@@ -287,7 +287,7 @@ int ustcomm_register_event(int sock,
 	int loglevel,
 	const char *signature,		/* event signature (input) */
 	size_t nr_fields,		/* fields */
-	const struct lttng_ust_event_field **fields,
+	const struct lttng_ust_event_field * const *fields,
 	const char *model_emf_uri,
 	uint32_t *id)			/* event id (output) */
 	__attribute__((visibility("hidden")));
@@ -300,7 +300,7 @@ int ustcomm_register_enum(int sock,
 	int session_objd,		/* session descriptor */
 	const char *enum_name,		/* enum name (input) */
 	size_t nr_entries,		/* entries */
-	const struct lttng_ust_enum_entry **entries,
+	const struct lttng_ust_enum_entry * const *entries,
 	uint64_t *id)			/* enum id (output) */
 	__attribute__((visibility("hidden")));
 
diff --git a/src/lib/lttng-ust/lttng-bytecode.c b/src/lib/lttng-ust/lttng-bytecode.c
index 8d3971bf..9222e1cc 100644
--- a/src/lib/lttng-ust/lttng-bytecode.c
+++ b/src/lib/lttng-ust/lttng-bytecode.c
@@ -179,7 +179,7 @@ int apply_field_reloc(const struct lttng_ust_event_desc *event_desc,
 		const char *field_name,
 		enum bytecode_op bytecode_op)
 {
-	const struct lttng_ust_event_field **fields, *field = NULL;
+	const struct lttng_ust_event_field * const *fields, *field = NULL;
 	unsigned int nr_fields, i;
 	struct load_op *op;
 	uint32_t field_offset = 0;
diff --git a/src/lib/lttng-ust/lttng-events.c b/src/lib/lttng-ust/lttng-events.c
index e8f9fd9f..445a3c39 100644
--- a/src/lib/lttng-ust/lttng-events.c
+++ b/src/lib/lttng-ust/lttng-events.c
@@ -516,7 +516,7 @@ int lttng_create_enum_check(const struct lttng_ust_type_common *type,
 
 static
 int lttng_create_all_event_enums(size_t nr_fields,
-		const struct lttng_ust_event_field **event_fields,
+		const struct lttng_ust_event_field * const *event_fields,
 		struct lttng_ust_session *session)
 {
 	size_t i;
diff --git a/src/lib/lttng-ust/lttng-ust-dynamic-type.c b/src/lib/lttng-ust/lttng-ust-dynamic-type.c
index f46c3231..06333906 100644
--- a/src/lib/lttng-ust/lttng-ust-dynamic-type.c
+++ b/src/lib/lttng-ust/lttng-ust-dynamic-type.c
@@ -161,7 +161,7 @@ const struct lttng_ust_event_field *lttng_ust_dynamic_type_field(int64_t value)
 	return dt_var_fields[value];
 }
 
-int lttng_ust_dynamic_type_choices(size_t *nr_choices, const struct lttng_ust_event_field ***choices)
+int lttng_ust_dynamic_type_choices(size_t *nr_choices, const struct lttng_ust_event_field * const **choices)
 {
 	*nr_choices = _NR_LTTNG_UST_DYNAMIC_TYPES;
 	*choices = dt_var_fields;