Merge pull request #5714 from alexischr/update_bockbuild

[mono.git] / mono / metadata / abi-details.h

diff --git a/mono/metadata/abi-details.h b/mono/metadata/abi-details.h
index 3f61191b3146cbdf38a3cac5aabd935bc63152ae..b0cdd521743fb30ec9f7c97f5b13e92dcf9e8bde 100644 (file)
--- a/mono/metadata/abi-details.h
+++ b/mono/metadata/abi-details.h
@@ -1,4 +1,5 @@
-/*
+/**
+ * \file
  * Copyright 2014 Xamarin Inc
  * Licensed under the MIT license. See LICENSE file in the project root for full license information.
  */
@@ -8,6 +9,20 @@
 #include <config.h>
 #include <glib.h>
 
+/*
+ * This file defines macros to compute sizes/alignments/field offsets which depend on
+ * the ABI. It is needed during cross compiling since the generated code needs to
+ * contain offsets which correspond to the ABI of the target, not the host.
+ * It defines the following macros:
+ * - MONO_ABI_SIZEOF(type) for every basic type
+ * - MONO_ABI_ALIGNOF(type) for every basic type
+ * - MONO_STRUCT_OFFSET(struct, field) for various runtime structures
+ * When not cross compiling, these correspond to the host ABI (i.e. sizeof/offsetof).
+ * When cross compiling, these are defined in a generated header file which is
+ * generated by the offsets tool in tools/offsets-tool. The name of the file
+ * is given by the --with-cross-offsets= configure argument.
+ */
+
 #define MONO_ABI_ALIGNOF(type) MONO_ALIGN_ ## type
 #define MONO_CURRENT_ABI_ALIGNOF_TYPEDEF(type) typedef struct { char c; type x; } Mono_Align_Struct_ ##type;
 #define MONO_CURRENT_ABI_ALIGNOF(type) ((int)G_STRUCT_OFFSET(Mono_Align_Struct_ ##type, x))