Only dump metadata for used targets

docs/writeup.txt

@@ -44,3 +44,6 @@ Plugin is per compilation unit
 	-> structs with same name can habe different definitions in different CUs (disallow this for now)
 	-> anonymous structs can not really be matched between CUs without type hash (disallow this for now)
 	-> later, use hash(type) to match structs between CUs to randomize as one
+
+Symbols must be object symbols because untyped/function symbols cause objtool issues in kernel build
+	-> can not find starting instruction of function

pinpoint/final/on_finish_unit.cpp

@@ -5,6 +5,7 @@
 #include <string>
 #include <filesystem>
 #include <fstream>
+#include <unordered_set>
 
 #include <safe-input.h>
 #include <safe-output.h>
@@ -153,9 +154,24 @@ void on_finish_unit(void* plugin_data, void* user_data) {
 
 	out << "SPSLR " << get_src_file() << " " << cu_uid << std::endl;
 
-	// Dump all target structs
+	// Construct set of all targets that are used by at least 1 ipin or dpin
+
+	std::unordered_set<UID> used_targets;
+
+	for (const DataPin& dpin : DataPin::all()) {
+		for (const DataPin::Component& c : dpin.components)
+			used_targets.insert(c.target);
+	}
+
+	for (const auto& [uid, ipin] : s2_pins())
+		used_targets.insert(ipin.target);
+
+	// Dump all USED target structs
 
 	for (const auto& [uid, target] : TargetType::all()) {
+		if (used_targets.find(uid) == used_targets.end())
+			continue;
+
 		// target <name> <local uid> <size> <field count>
 		out << "target " << target.name() << " " << uid << " " << target.size()
 			<< " " << target.fields().size() << std::endl;