Planning

docs/plan.txt

@@ -7,3 +7,4 @@ Approach:
 - Right after expansion to RTL, pattern match set of RTL instructions with same location to graph
 	- Add notes (persistent over RTL transformations) to any RTL instruction that is relevant
 - After all RTL optimizations, add assembly labels before relevant RTL instructions (identified by notes)
+- Might need an additional early pass to prevent COMPONENT_REFs to constant/static stuff from being folded early

plugin/access_discover.cpp

@@ -44,8 +44,29 @@ static int scan_gimple_statement(const char* funcname, gimple_stmt_iterator* gsi
 	}
 
 	Build map: location->LocationPattern
+	Build GimpleStatementPattern tree from individual gimple statement
+	Add GimpleStatementPattern to LocationPattern (attached at matching variable names (potentially unnamed ssa))
+	Patterns include markers for member offsets (type, member, value)
+	Later load a set of RTLInstructionPattern to match the patterns
 	*/
+
 	print_gimple_statement(gsi_stmt(*gsi));
+
+	gimple* stmt = gsi_stmt(*gsi);
+	enum gimple_code stmt_code = gimple_code(stmt);
+
+	switch (stmt_code) {
+		case GIMPLE_CALL:
+			// check for offsetof, then fall through to operand scanning
+		case GIMPLE_ASSIGN:
+		case GIMPLE_COND:
+		case GIMPLE_LABEL:
+		case GIMPLE_RETURN:
+			return 0;
+		default:
+			return 1;
+	}
+
 	return 0;
 }
 
@@ -72,9 +93,10 @@ unsigned int access_discover_pass::execute(function* fun) {
 	basic_block bb;
 	FOR_EACH_BB_FN(bb, fun) {
 		for (gimple_stmt_iterator gsi = gsi_start_bb(bb); !gsi_end_p(gsi); gsi_next(&gsi)) {
-			int stmt_scan_success;
-			if ((stmt_scan_success = scan_gimple_statement(funcname, &gsi)) != 0)
-				return stmt_scan_success;
+			if (scan_gimple_statement(funcname, &gsi) != 0) {
+				internal_error("fatal error in spslr plugin: %s", "failed to scan gimple statement");
+				return 0;
+			}
 		}
 	}