From 7d3fc17e815073e24d1f1506305e6ae0c4753be7 Mon Sep 17 00:00:00 2001
From: Jay Krell <jaykrell@microsoft.com>
Date: Wed, 16 Oct 2019 01:12:41 -0700
Subject: [PATCH] Fix C++ WebAssembly build. (#17302)

---
 mono/metadata/marshal.h     |  3 ---
 mono/utils/dlmalloc.h       | 16 ++++++++++++++++
 mono/utils/mono-mmap-wasm.c |  2 +-
 3 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/mono/metadata/marshal.h b/mono/metadata/marshal.h
index f19be3994d6..b65786cb5d3 100644
--- a/mono/metadata/marshal.h
+++ b/mono/metadata/marshal.h
@@ -550,9 +550,6 @@ mono_marshal_set_last_error_windows (int error);
 void 
 mono_struct_delete_old (MonoClass *klass, char *ptr);
 
-MonoObject*
-mono_object_isinst_icall (MonoObject *obj, MonoClass *klass);
-
 int
 mono_emit_marshal (EmitMarshalContext *m, int argnum, MonoType *t, 
 	      MonoMarshalSpec *spec, int conv_arg, 
diff --git a/mono/utils/dlmalloc.h b/mono/utils/dlmalloc.h
index db2614fa6cd..56192152e78 100644
--- a/mono/utils/dlmalloc.h
+++ b/mono/utils/dlmalloc.h
@@ -28,6 +28,22 @@
 #include <stddef.h>   /* for size_t */
 #include <mono/utils/mono-compiler.h>
 
+// Returning an undefined struct by value from extern "C"
+// is sometimes an error. Mono does not use the code (dlmallinfo)..
+//
+// Other fixes:
+//   - define the struct
+//   - #if __cplusplus
+//   - #if HOST_WASM
+//   - #ifndef HAVE_USR_INCLUDE_MALLOC_H
+//   - Make it not extern "C".
+//   - Return the struct through an out parameter.
+//   - remove extern "C" entirely in dlmalloc.
+//
+// Mono does not use the function (dlmallinfo).
+//
+#define NO_MALLINFO 1 /* mono */
+
 #ifdef __cplusplus
 extern "C" {
 #endif
diff --git a/mono/utils/mono-mmap-wasm.c b/mono/utils/mono-mmap-wasm.c
index 344efa21924..10485f720dc 100644
--- a/mono/utils/mono-mmap-wasm.c
+++ b/mono/utils/mono-mmap-wasm.c
@@ -155,7 +155,7 @@ mono_valloc_aligned (size_t size, size_t alignment, int flags, MonoMemAccountTyp
 int
 mono_vfree (void *addr, size_t length, MonoMemAccountType type)
 {
-	VallocInfo *info = valloc_hash ? g_hash_table_lookup (valloc_hash, addr) : NULL;
+	VallocInfo *info = (VallocInfo*)(valloc_hash ? g_hash_table_lookup (valloc_hash, addr) : NULL);
 	int res;
 
 	if (info) {
-- 
2.11.4.GIT