[C#] Use Heap{Alloc,Free} rather than malloc/free on Windows

We generally expect to allocate pointers in C which Rust will free,
and vice versa. On Windows, this requires that we use the same
allocation path as Rust's stdlib does, which is actually
`Heap{Alloc,Free}`, not `malloc`/`free`. Here, we swap the heap
allocation functions we call, fixing heap corruption issues on
Windows.

Author: TheBlueMatt

csharp_strings.py

@@ -3,7 +3,9 @@
 import sys
 
 class Target(Enum):
-    CSHARP = 1,
+    WINDOWS = 1,
+    LINUX = 2,
+    PTHREAD = 3,
 
 def first_to_lower(string: str) -> str:
     first = string[0]
@@ -188,7 +190,25 @@ def __init__(self, DEBUG: bool, target: Target, outdir: str, **kwargs):
 
         self.c_file_pfx = self.c_file_pfx + "#include <stdio.h>\n#define DEBUG_PRINT(...) fprintf(stderr, __VA_ARGS__)\n"
 
-        if not DEBUG or sys.platform == "darwin":
+        if self.target == Target.WINDOWS:
+            self.c_file_pfx = self.c_file_pfx + """#include <heapapi.h>
+static HANDLE process_heap = NULL;
+static inline void* init_heap() {
+	if (UNLIKELY(process_heap == NULL)) {
+		// Assume pointer writes wont tear, which is true where we need it.
+		process_heap = GetProcessHeap();
+	}
+}
+static inline void* MALLOC(size_t a, const char* _) {
+	init_heap();
+	return HeapAlloc(process_heap, HEAP_ZERO_MEMORY, a);
+}
+#define do_MALLOC(a, b, _c) MALLOC(a, b)
+#define FREE(p) if ((uint64_t)(p) > 4096) { init_heap(); HeapFree(process_heap, 0, p); }
+#define CHECK_ACCESS(p)
+#define CHECK_INNER_FIELD_ACCESS_OR_NULL(v)
+"""
+        elif not DEBUG or self.target != Target.LINUX:
             self.c_file_pfx = self.c_file_pfx + """#define do_MALLOC(a, _b, _c) malloc(a)
 #define MALLOC(a, _) malloc(a)
 #define FREE(p) if ((uint64_t)(p) > 4096) { free(p); }
@@ -214,7 +234,7 @@ def __init__(self, DEBUG: bool, target: Target, outdir: str, **kwargs):
 }
 """
 
-            if sys.platform != "darwin":
+            if self.target == Target.LINUX:
                 self.c_file_pfx += """
 // Running a leak check across all the allocations and frees of the JDK is a mess,
 // so instead we implement our own naive leak checker here, relying on the -wrap

genbindings.py

@@ -28,10 +28,17 @@
     target = typescript_strings.Target.NODEJS
     if len(sys.argv) == 8 and sys.argv[7] == 'browser':
         target = typescript_strings.Target.BROWSER
-elif sys.argv[6] == "c_sharp":
+elif sys.argv[6].startswith("c_sharp"):
     import csharp_strings
     from csharp_strings import Consts
-    target = csharp_strings.Target.CSHARP
+    if sys.argv[6] == "c_sharp-win":
+        target = csharp_strings.Target.WINDOWS
+    elif sys.argv[6] == "c_sharp-darwin":
+        target = csharp_strings.Target.PTHREAD
+    elif sys.argv[6] == "c_sharp-linux":
+        target = csharp_strings.Target.LINUX
+    else:
+        assert False
 elif sys.argv[6] == "python":
     import python_strings
     from python_strings import Consts

genbindings.sh

@@ -106,7 +106,10 @@ if [ "$2" = "c_sharp" ]; then
 	echo "Creating C# bindings..."
 	mkdir -p c_sharp/src/org/ldk/{enums,structs,impl}
 	rm -f c_sharp/src/org/ldk/{enums,structs,impl}/*.cs
-	./genbindings.py "./lightning.h" c_sharp/src/org/ldk/impl c_sharp/src/org/ldk c_sharp/ $DEBUG_ARG c_sharp $4 $TARGET_STRING
+	GEN_PLAT="c_sharp-linux"
+	[ "$IS_WIN" = "true" ] && GEN_PLAT="c_sharp-win"
+	[ "$IS_MAC" = "true" ] && GEN_PLAT="c_sharp-darwin"
+	./genbindings.py "./lightning.h" c_sharp/src/org/ldk/impl c_sharp/src/org/ldk c_sharp/ $DEBUG_ARG $GEN_PLAT $4 $TARGET_STRING
 	rm -f c_sharp/bindings.c
 	if [ "$3" = "true" ]; then
 		echo "#define LDK_DEBUG_BUILD" > c_sharp/bindings.c
@@ -151,6 +154,8 @@ if [ "$2" = "c_sharp" ]; then
 	[ "$IS_MAC" = "true" -a "$IS_APPLE_CLANG" = "false" ] && LINK="$LINK -fuse-ld=lld"
 	[ "$IS_MAC" = "true" -a "$IS_APPLE_CLANG" = "false" ] && echo "WARNING: Need at least upstream clang 13!"
 	[ "$IS_MAC" = "false" -a "$3" != "false" ] && LINK="$LINK -Wl,-wrap,calloc -Wl,-wrap,realloc -Wl,-wrap,malloc -Wl,-wrap,free"
+	[ "$IS_WIN" = "true" ] && LINK="$LINK --target=x86_64-pc-windows-gnu -lbcrypt -lntdll -static-libgcc"
+	[ "$IS_WIN" = "true" ] && COMPILE="$COMPILE --target=x86_64-pc-windows-gnu -I/usr/x86_64-w64-mingw32/sys-root/mingw/include/ -I/usr/x86_64-w64-mingw32/include/"
 
 	if [ "$3" = "true" ]; then
 		$COMPILE $LINK -o libldkcsharp_debug$LDK_TARGET_SUFFIX.so -g -fsanitize=address -shared-libasan -rdynamic -I"$1"/lightning-c-bindings/include/ c_sharp/bindings.c "$1"/lightning-c-bindings/target/$LDK_TARGET/debug/libldk.a -lm
@@ -159,8 +164,6 @@ if [ "$2" = "c_sharp" ]; then
 		[ "$IS_APPLE_CLANG" = "false" ] && COMPILE="$COMPILE -flto"
 		[ "$IS_MAC" = "false" ] && LINK="$LINK -Wl,--no-undefined"
 		[ "$IS_WIN" = "false" ] && LINK="$LINK -Wl,--lto-O3"
-		[ "$IS_WIN" = "true" ] && LINK="$LINK --target=x86_64-pc-windows-gnu -L/usr/lib/gcc/x86_64-w64-mingw32/12-win32/ -lbcrypt -lntdll -static-libgcc"
-		[ "$IS_WIN" = "true" ] && COMPILE="$COMPILE --target=x86_64-pc-windows-gnu"
 		LDK_LIB="$1"/lightning-c-bindings/target/$LDK_TARGET/release/libldk.a
 		if [ "$IS_MAC" = "false" -a "$IS_WIN" = "false" -a "$4" = "false" ]; then
 			LINK="$LINK -Wl,--version-script=c_sharp/libcode.version -Wl,--build-id=0x0000000000000000"