fixed local Q-Register management on certain broken platforms

 * on MSVCRT/MinGW, space allocated with alloca()/g_newa() was apparently
   freed once the first exception was caught.
   This prevented the proper destruction of local Q-Reg tables and
   broke the Windows port.
 * Since all alternatives to alloca() like VLAs are not practical,
   the default Q-Register initialization has been moved out of the
   QRegisterTable constructor into QRegisterTable::insert_defaults().
 * The remaining QRegisterTable initialization and destruction is
   very cheap, so we simply reserve an empty QRegisterTable for
   local registers on every Execute::macro() call.
   The default registers are only initialized when required, though.
 * All of this has to change anyway once we replace the
   C++ call-stack approach to macro calls with our own macro
   call frame memory management.

1 files changed, 10 insertions, 1 deletions

diff --git a/src/qregisters.h b/src/qregisters.h
index 4648149..fc7a624 100644
--- a/src/qregisters.h
+++ b/src/qregisters.h
@@ -286,6 +286,12 @@ public:
 
 class QRegisterTable : private RBTreeString, public Object {
 	class UndoTokenRemove : public UndoToken {
+		/*
+		 * NOTE: Storing the table here is only necessary since
+		 * we may have to remove from a global or local Q-Reg
+		 * table. This could be avoided using a separate
+		 * subclass for local registers.
+		 */
 		QRegisterTable *table;
 		QRegister *reg;
 
@@ -303,7 +309,8 @@ class QRegisterTable : private RBTreeString, public Object {
 	bool must_undo;
 
 public:
-	QRegisterTable(bool _undo = true);
+	QRegisterTable(bool _must_undo = true)
+	              : must_undo(_must_undo) {}
 
 	~QRegisterTable()
 	{
@@ -339,6 +346,8 @@ public:
 		return insert(buf);
 	}
 
+	void insert_defaults(void);
+
 	inline QRegister *
 	find(const gchar *name)
 	{