rts: Introduce and use ExecPage abstraction

Here we introduce a very thin abstraction for allocating, filling, and
freezing executable pages to replace allocateExec.

(cherry picked from commit 0e875c3f1d7373812ddae9962edfc9538465d2ed)

2 files changed, 19 insertions, 0 deletions

diff --git a/includes/Rts.h b/includes/Rts.h
index 0f96ba2eca..5e657e07ce 100644
--- a/includes/Rts.h
+++ b/includes/Rts.h
@@ -223,6 +223,7 @@ void _assertFail(const char *filename, unsigned int linenum)
 #include "rts/ForeignExports.h"
 
 /* Other RTS external APIs */
+#include "rts/ExecPage.h"
 #include "rts/Parallel.h"
 #include "rts/Signals.h"
 #include "rts/BlockSignals.h"
diff --git a/includes/rts/ExecPage.h b/includes/rts/ExecPage.h
new file mode 100644
index 0000000000..4261b71259
--- /dev/null
+++ b/includes/rts/ExecPage.h
@@ -0,0 +1,18 @@
+/*
+ * Utilities for managing dynamically-allocated executable pages.
+ */
+
+#pragma once
+
+typedef struct {
+    char contents;
+} ExecPage;
+
+/* Allocate a writable page. */
+ExecPage *allocateExecPage(void);
+
+/* Make a page previously allocated by allocateExecPage. */
+void freezeExecPage(ExecPage *page);
+
+/* Free a page previously allocated by allocateExecPage. */
+void freeExecPage(ExecPage *page);