From cee3515218912233b7da74e649a7957a109e5b76 Mon Sep 17 00:00:00 2001
From: Matthew Leach <matthew@mattleach.net>
Date: Wed, 10 Feb 2021 20:56:25 +0000
Subject: [PATCH] [lang] add a tree type that represents an FFI closure

We will be using FFI closures for allowing function pointers to be created. Add
a tree type that allows us to track the use of FFI allocated memory and GC it
when needed.
---
 src/c.lang                 |  7 +++++++
 src/gc.c                   |  4 ++++
 src/tree-dump-primitives.h | 11 +++++++++++
 src/tree.h                 |  1 +
 4 files changed, 23 insertions(+)

diff --git a/src/c.lang b/src/c.lang
index 63458b2..361fa40 100644
--- a/src/c.lang
+++ b/src/c.lang
@@ -6,6 +6,8 @@
   (ptr "void *")
   (sz "size_t")
   (flag "bool")
+  (ffi_cif "ffi_cif *")
+  (ffi_closure "ffi_closure *")
   (comp_decl_type "compound_type")
   (live_var_val "union value *"))
 
@@ -184,6 +186,11 @@
 (deftype T_FN_CALL "Function Call" "tFNCALL"
          ("ID" "ARGS"))
 
+(deftype T_CLOSURE "Closure Call" "tCLOSURE"
+         ("ARG_TYPES" "RET_TYPE" "FN"
+          ("CIF" ffi_cif)
+          ("CLOSURE" ffi_closure)))
+
 (deftype T_FN_ARG "Function Argument" "tFNARG"
          ("EXP"))
 
diff --git a/src/gc.c b/src/gc.c
index 2d00420..e68ce52 100644
--- a/src/gc.c
+++ b/src/gc.c
@@ -101,6 +101,10 @@ static void dealloc_object(gc_obj obj)
     case E_ALLOC:
         free(tALLOC_PTR(t));
         break;
+    case T_CLOSURE:
+        ffi_closure_free(tCLOSURE_CLOSURE(t));
+        free(tCLOSURE_CIF(t));
+        break;
     default:
         /* All other types don't contain any other referencies to
          * dynamic memory. */
diff --git a/src/tree-dump-primitives.h b/src/tree-dump-primitives.h
index 8af1c43..b2a8d93 100644
--- a/src/tree-dump-primitives.h
+++ b/src/tree-dump-primitives.h
@@ -68,6 +68,17 @@ static inline void tree_dump_integer(tree t, mpz_t val, enum DUMP_TYPE dt)
     gmp_fprintf(stderr, "%Zd", val);
 }
 
+static inline void tree_dump_ffi_closure(tree t, ffi_closure *closure, enum DUMP_TYPE dt)
+{
+    return;
+}
+
+static inline void tree_dump_ffi_cif(tree t, ffi_cif *closure,
+                                         enum DUMP_TYPE dt)
+{
+    return;
+}
+
 static inline void tree_dump_comp_decl_type(tree t, compound_type v, enum DUMP_TYPE dt)
 {
     switch(v) {
diff --git a/src/tree.h b/src/tree.h
index c3b5118..38238a1 100644
--- a/src/tree.h
+++ b/src/tree.h
@@ -8,6 +8,7 @@
 #include <string.h>
 #include <stdbool.h>
 #include <setjmp.h>
+#include <ffi.h>
 #include "list.h"
 #include "tree-access.h"