From: Olivier Dion <odion@efficios.com>
Date: Fri, 25 Oct 2024 16:12:31 +0000 (-0400)
Subject: Add SIDE_STATIC_CHECK_DISABLE_DUPLICATED_FIELDS
X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=5a41320faf2ebc484fe02cc300604338f3e2da19;p=libside.git

Add SIDE_STATIC_CHECK_DISABLE_DUPLICATED_FIELDS

New tunable for the static checker that can be #define/#undef around
code where the static checking of duplicated/null fields is disabled.

Change-Id: I4cf51561d0a21f59b8577813d7aa1b9b0fc789a8
Signed-off-by: Olivier Dion <odion@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---

diff --git a/include/side/static-check.h b/include/side/static-check.h
index 88f5b14..aaaef9d 100644
--- a/include/side/static-check.h
+++ b/include/side/static-check.h
@@ -132,6 +132,44 @@
 
 /* User configuration. */
 
+/*
+ * SIDE_STATIC_CHECK_DISABLE_DUPLICATED_FIELDS: Disable checking of duplicated
+ * fields names and null fields names.  The macro must be defined as an object
+ * macro with void expansion before the code where the check must be disabled.
+ * The macro can then be undefined for allowing the check again.
+ *
+ * The intent of this tunable is to allow big list of fields.  Indeed, the
+ * static checker ensures by default that no duplicated fields exist in a list of
+ * fields.  This is a combinatory problem where the number of expansion required
+ * for doing so is quadratic.
+ *
+ * In fact, given N fields, the number of expansions required is binomial(N, 2).
+ * See `SIDE_SC_MAP_COMB'.
+ *
+ * The tunable can be used around the following forms:
+ *
+ *	- side_define_struct()
+ *	- side_export_event()
+ *	- side_export_event_variadic()
+ *	- side_hidden_event()
+ *	- side_hidden_event_variadic()
+ *	- side_static_event()
+ *	- side_static_event_variadic()
+ *
+ * Example:
+ *
+ *	// The following duplicated fields won't be caught by
+ *	// the static checker.
+ *	#define SIDE_STATIC_CHECK_DISABLE_DUPLICATED_FIELDS
+ *	static side_define_struct(my_struct,
+ *		side_field_list(
+ *			side_field_u32("x"),
+ *			side_field_s64("x"),
+ *		)
+ *	);
+ *	#undef SIDE_STATIC_CHECK_DISABLE_DUPLICATED_FIELDS
+ */
+
 /*
  * SIDE_STATIC_CHECK_MAX_EVAL_LEVEL: Determine the maximum level of expansion by
  * the static checker.  Each level allow for 4 more time expansions.  Therefore,
@@ -480,9 +518,39 @@ template <typename T, typename U>
  *
  *	side_field_list(side_field_*(...) ...)
  */
-#define SIDE_SC_CHECK_FIELD_NAMES(_fields)				\
+#define SIDE_SC_CHECK_FIELD_NAMES_SIDE_STATIC_CHECK_DISABLE_DUPLICATED_FIELDS(_fields) \
 	SIDE_SC_CHECK_FIELDS_NAMES_PRIMITIVE(_fields, SIDE_SC_NAME_OF_##_fields)
 
+#define SIDE_SC_CHECK_FIELD_NAMES_(...) SIDE_EXPECT_SEMICOLON()
+
+#define SIDE_SC_MAYBE_CHECK_FIELD_NAMES(fn, ...)	\
+	fn(__VA_ARGS__)
+
+/*
+ * This looks counter intuitive.
+ *
+ * Let's define `SIDE_STATIC_CHECK_DISABLE_DUPLICATED_FIELDS' as the `tunable'
+ * for clarity.
+ *
+ * When the tunable is defined, the user ask to not check the fields names.
+ * This is done by concatenating the expansion of `SIDE_SC_CHECK_FIELD_NAMES_'
+ * and the tunable, resulting in `SIDE_SC_CHECK_FIELD_NAMES_' again, which is a
+ * function macro, thus no further expansion is done yet.  Parentheses are
+ * introduced in `SIDE_SC_MAYBE_CHECK_FIELD_NAMES`, to call the function macro,
+ * in this case resulting in the expansion of `SIDE_EXPECT_SEMICOLON'.
+ *
+ * When the tunable is not defined, then the resulting function-token passed to
+ * `SIDE_SC_CHECK_FIELD_NAMES_' will be
+ * `SIDE_SC_CHECK_FIELD_NAMES_SIDE_STATIC_CHECK_DISABLE_DUPLICATED_FIELDS`.
+ * When applied with the list of fields, this macro does the static check of
+ * fields names.
+ *
+ * This is all confusing because the macro with the word `DISABLE' is actually
+ * used when the check is done.
+ */
+#define SIDE_SC_CHECK_FIELD_NAMES(...)					\
+	SIDE_SC_MAYBE_CHECK_FIELD_NAMES(SIDE_SC_CAT(SIDE_SC_CHECK_FIELD_NAMES_, SIDE_STATIC_CHECK_DISABLE_DUPLICATED_FIELDS), ##__VA_ARGS__)
+
 /*
  * Used by SIDE_SC_NAME_OF_* macros to extract field name of the form
  * `side_field_*(_name, ...)'.