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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
//*****************************************************************************
// VerifyLayouts.h
//
//
// Make sure that layouts of MD data strucutres doesn't change accidentally
//
//*****************************************************************************
// The code in MD\DataSource\TargetTypes.* takes a direct dependency on
// the layouts of types in MD. This is used by the debugger to read metadata
// from a seperate process by deserializing the memory for these datastructures.
//
// You are probably reading this comment because you changed a layout and
// one of the static_asserts failed during build. This is what you should
// do to fix it:
//
// a) Go to clr\src\Debug\EE\Debugger.cpp and increment the global version counter
// m_mdDataStructureVersion set in Debugger::Debugger()
// Please comment the change there with a new entry in the version table
//
// b) If a define is conditionally changing the layout:
// i) add, if needed, an entry to the list of define bits in
// clr\src\Debug\EE\debugger.h Debugger::_Target_Defines
// ii) add code like this that sets the bit in the Debugger::_defines static
// variable
// #ifdef MY_DEFINE
// | DEFINE_MY_DEFINE
// #endif
//
// c) Update the code in MD\DataSource\TargetTypes.h/cpp to deserialize your
// new layout correctly. The code needs to work for any version of the layouts
// with or without defines set. Your reader code can access the current version
// and defines by calling:
// reader.GetMDStructuresVersion()
// reader.IsDefined(Define_XYZ)
//
// d) If your changes affect what a debugger should be reading in order to fetch
// metadata then you probably need to change other parts of the debugger
// implementation as well. In general the debugger cares about the schema,
// TableDefs, storage signature, table records, and storage pools.
//
// e) AFTER you have fixed up the debugger stuff above, now its time to update
// layout definitions so the static asserts will quiet down. Check out
// the comments in VerifyLayouts.inc for how to do that.
//
// Thanks for helping us keep the debugger working :)
//
//-------------------------------------------------------------------------------
// Type layout verification
//
//
// These macros includes VerifyLayouts.inc a few times with different definitions to build up
// the source. The final result should look something like this:
// (don't assume specific type names/fields/offsets/sizes are accurate in this example)
//
//
// class VerifyLayoutsMD
// {
//
// static const expected_offset_of_first_field_in_CMiniMdRW = 208;
// static const actual_offset_of_first_field_in_CMiniMdRW =
// 208;
// static const offset_of_field_after_CMiniMdRW_m_Schema =
// 312;
// static const offset_of_field_after_CMiniMdRW_m_Tables =
// 316;
// ... many more lines like this covering all fields in all marked up types ...
//
//
// static const alignment_of_first_field_in_CMiniMdRW =
// 4;
// static const alignment_of_field_after_CMiniMdRW_m_Schema =
// 8;
// static const alignment_of_field_after_CMiniMdRW_m_Tables =
// 8;
// ... many more lines like this cover all fields in all marked up types ...
//
//
// static_assert_no_msg(expected_offset_of_first_field_in_CMiniMdRW == actual_offset_of_first_field_in_CMiniMdRW);
// static_assert_no_msg(offset_of_field_after_CMiniMdRW_m_Schema ==
// ALIGN_UP(offsetof(CMiniMdRW, m_Schema) + 104, alignment_of_field_after_CMiniMdRW_m_Schema));
// static_assert_no_msg(offset_of_field_after_CMiniMdRW_m_Tables ==
// ALIGN_UP(offsetof(CMiniMdRW, m_Tables) + 4, alignment_of_field_after_CMiniMdRW_m_Tables));
// ... many more lines like this cover all fields in all marked up types ...
//
// };
//
//
//
//
#ifdef FEATURE_METADATA_VERIFY_LAYOUTS
#include <stddef.h> // offsetof
#include "static_assert.h"
#include "metamodel.h"
#include "WinMDInterfaces.h"
#include "MDInternalRW.h"
// other types provide friend access to this type so that the
// offsetof macro can access their private fields
class VerifyLayoutsMD
{
// we have a bunch of arrays with this fixed size, make sure it doesn't change
static_assert_no_msg(TBL_COUNT == 45);
#define IGNORE_COMMAS(...) __VA_ARGS__ // use this to surround templated types with commas in the name
#define BEGIN_TYPE(typeName, initialFieldOffset) BEGIN_TYPE_ESCAPED(typeName, typeName, initialFieldOffset)
#define FIELD(typeName, fieldName, fieldSize) ALIGN_FIELD_ESCAPED(typeName, typeName, fieldName, fieldSize, fieldSize)
#define ALIGN_FIELD(typeName, fieldName, fieldSize, fieldAlign) ALIGN_FIELD_ESCAPED(typeName, typeName, fieldName, fieldSize, fieldAlign)
#define FIELD_ESCAPED(typeName, escapedTypeName, fieldName, fieldSize) ALIGN_FIELD_ESCAPED(typeName, escapedTypeName, fieldName, fieldSize, fieldSize)
#define END_TYPE(typeName, typeAlign) END_TYPE_ESCAPED(typeName, typeName, typeAlign)
#define BEGIN_TYPE_ESCAPED(typeName, typeNameEscaped, initialFieldOffset) \
static const expected_offset_of_first_field_in_##typeNameEscaped## = initialFieldOffset; \
static const actual_offset_of_first_field_in_##typeNameEscaped## =
#define ALIGN_FIELD_ESCAPED(typeName, typeNameEscaped, fieldName, fieldSize, fieldAlign) \
offsetof(IGNORE_COMMAS(typeName), fieldName); \
static const offset_of_field_after_##typeNameEscaped##_##fieldName =
#define BITFIELD(typeName, fieldName, fieldOffset, fieldSize) \
fieldOffset; \
static const offset_of_field_after_##typeName##_##fieldName =
#define END_TYPE_ESCAPED(typeName, typeNameEscaped, typeAlignentSize) \
sizeof(typeName);
#include "VerifyLayouts.inc"
#undef BEGIN_TYPE_ESCAPED
#undef ALIGN_FIELD_ESCAPED
#undef END_TYPE_ESCAPED
#undef BITFIELD
#define BEGIN_TYPE_ESCAPED(typeName, escapedTypeName, initialFieldOffset) \
static const alignment_of_first_field_in_##escapedTypeName =
#define ALIGN_FIELD_ESCAPED(typeName, escapedTypeName, fieldName, fieldSize, fieldAlign) \
fieldAlign; \
static const alignment_of_field_after_##escapedTypeName##_##fieldName =
#define BITFIELD(typeName, fieldName, fieldOffset, fieldSize) \
fieldSize; \
static const alignment_of_field_after_##typeName##_##fieldName =
#define END_TYPE_ESCAPED(typeName, escapedTypeName, typeAlignmentSize) \
typeAlignmentSize;
#include "VerifyLayouts.inc"
#undef BEGIN_TYPE_ESCAPED
#undef ALIGN_FIELD_ESCAPED
#undef END_TYPE_ESCAPED
#undef BITFIELD
#define BEGIN_TYPE_ESCAPED(typeName, escapedTypeName, initialFieldOffset) \
static_assert_no_msg(expected_offset_of_first_field_in_##escapedTypeName == actual_offset_of_first_field_in_##escapedTypeName);
#define ALIGN_UP(value, alignment) (((value) + (alignment) - 1)&~((alignment) - 1))
#define ALIGN_FIELD_ESCAPED(typeName, escapedTypeName, fieldName, fieldSize, fieldAlign) \
static_assert_no_msg(offset_of_field_after_##escapedTypeName##_##fieldName == \
ALIGN_UP(offsetof(IGNORE_COMMAS(typeName), fieldName) + fieldSize, alignment_of_field_after_##escapedTypeName##_##fieldName));
#define BITFIELD(typeName, fieldName, fieldOffset, fieldSize) \
static_assert_no_msg(offset_of_field_after_##typeName##_##fieldName == \
ALIGN_UP(fieldOffset + fieldSize, alignment_of_field_after_##typeName##_##fieldName));
#define END_TYPE_ESCAPED(typeName, escapedTypeName, typeAlignmentSize)
#include "VerifyLayouts.inc"
};
#endif //FEATURE_METADATA_VERIFY_LAYOUTS
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