From ea77bdf8697ea78b177a4e68b661af93da07d494 Mon Sep 17 00:00:00 2001
From: Bill Holmes <bill.holmes@unity3d.com>
Date: Fri, 10 Sep 2021 09:50:55 -0400
Subject: [PATCH] Enable COM in classlibs for win32

The runtime for Windows still has valid implementations for
COM calls. In the case of this bug IsComOjbect needs to behave
correctly.

The intention of this PR is to set DISABLE_COM for only mac
and linux for unity jit and unity apt profiles.

fixes case 1358705
---
 mcs/build/profiles/unityaot.make                      | 11 +++++++++--
 mcs/build/profiles/unityjit.make                      |  4 +++-
 .../corlib/System.Runtime.InteropServices/Marshal.cs  |  2 +-
 3 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/mcs/build/profiles/unityaot.make b/mcs/build/profiles/unityaot.make
index 779c260ad8ca..060115d09cac 100644
--- a/mcs/build/profiles/unityaot.make
+++ b/mcs/build/profiles/unityaot.make
@@ -31,7 +31,6 @@ PROFILE_MCS_FLAGS = \
 	-d:UNITY \
 	-d:UNITY_AOT \
 	-d:MOBILE,MOBILE_LEGACY \
-	-d:DISABLE_COM \
 	-d:FULL_AOT_DESKTOP	\
 	-d:FULL_AOT_RUNTIME \
 	$(PLATFORM_FLAGS) \
@@ -46,4 +45,12 @@ NO_INSTALL = yes
 AOT_FRIENDLY_PROFILE = yes
 ALWAYS_AOT_BCL = yes
 MOBILE_PROFILE = yes
-NO_SRE = yes
\ No newline at end of file
+NO_SRE = yes
+
+ifeq ($(HOST_PLATFORM),macos)
+PROFILE_MCS_FLAGS += -d:DISABLE_COM
+endif
+
+ifeq ($(HOST_PLATFORM),linux)
+PROFILE_MCS_FLAGS += -d:DISABLE_COM
+endif
diff --git a/mcs/build/profiles/unityjit.make b/mcs/build/profiles/unityjit.make
index 5133e933e1be..94495c6d708b 100644
--- a/mcs/build/profiles/unityjit.make
+++ b/mcs/build/profiles/unityjit.make
@@ -11,7 +11,7 @@ profile-check:
 	@:
 
 DEFAULT_REFERENCES = mscorlib
-PROFILE_MCS_FLAGS = -d:NET_4_0 -d:NET_4_5 -d:NET_4_6 -d:MONO -d:UNITY_JIT -d:UNITY -d:WIN_PLATFORM -d:DISABLE_COM -nowarn:1699 -nostdlib $(PLATFORM_DEBUG_FLAGS)
+PROFILE_MCS_FLAGS = -d:NET_4_0 -d:NET_4_5 -d:NET_4_6 -d:MONO -d:UNITY_JIT -d:UNITY -d:WIN_PLATFORM -nowarn:1699 -nostdlib $(PLATFORM_DEBUG_FLAGS)
 API_BIN_PROFILE = v4.7.1
 
 FRAMEWORK_VERSION = 4.5
@@ -20,8 +20,10 @@ XBUILD_VERSION = 4.0
 ifeq ($(HOST_PLATFORM),macos)
 MONO_FEATURE_APPLETLS=1
 ENABLE_GSS=1
+PROFILE_MCS_FLAGS += -d:DISABLE_COM
 endif
 
 ifeq ($(HOST_PLATFORM),linux)
 ENABLE_GSS=1
+PROFILE_MCS_FLAGS += -d:DISABLE_COM
 endif
diff --git a/mcs/class/corlib/System.Runtime.InteropServices/Marshal.cs b/mcs/class/corlib/System.Runtime.InteropServices/Marshal.cs
index 4e1a4982dcf4..29d55eeb5530 100644
--- a/mcs/class/corlib/System.Runtime.InteropServices/Marshal.cs
+++ b/mcs/class/corlib/System.Runtime.InteropServices/Marshal.cs
@@ -856,7 +856,7 @@ public static object GetUniqueObjectForIUnknown (IntPtr unknown)
 			throw new PlatformNotSupportedException ();
 		}
 
-#if (!MOBILE && !UNITY) || UNITY_AOT
+#if (!MOBILE && !DISABLE_COM) || (UNITY_AOT && !DISABLE_COM)
 		[MethodImplAttribute (MethodImplOptions.InternalCall)]
 		public extern static bool IsComObject (object o);
 #else