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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.
/*****************************************************************************
*
* GC Information Encoding API
*
* This is an older well-tested implementation
* now used to verify the real encoding
* Define VERIFY_GCINFO to enable the verification
*
*/
#ifdef VERIFY_GCINFO
#ifndef __DBGGCINFOENCODER_H__
#define __DBGGCINFOENCODER_H__
#include <windows.h>
#include <wchar.h>
#include <stdio.h>
#include "utilcode.h"
#include "corjit.h"
#include "list.h" // for SList
#include "arraylist.h"
#include "stdmacros.h"
#include "gcinfotypes.h"
class IJitAllocator;
namespace DbgGcInfo {
//-----------------------------------------------------------------------------
// The following macro controls whether the encoder has to call the IJitAllocator::Free method
// Don't call IJitAllocator::Free for mscorjit64.dll
//-----------------------------------------------------------------------------
//#define MUST_CALL_JITALLOCATOR_FREE
class BitStreamWriter
{
public:
BitStreamWriter( IJitAllocator* pAllocator );
void Write( size_t data, int count );
inline size_t GetBitCount()
{
return m_BitCount;
}
inline size_t GetByteCount()
{
return ( m_BitCount + 7 ) / 8;
}
void CopyTo( BYTE* buffer );
void Dispose();
//--------------------------------------------------------
// Encode variable length numbers
// Uses base+1 bits at minimum
// Bits 0..(base-1) represent the encoded quantity
// If it doesn't fit, set bit #base to 1 and use base+1 more bits
//--------------------------------------------------------
int EncodeVarLengthUnsigned( size_t n, int base )
{
_ASSERTE((base > 0) && (base < sizeof(size_t)*8));
size_t numEncodings = 1 << base;
int bitsUsed = base+1;
for( ; ; bitsUsed += base+1)
{
if( n < numEncodings )
{
Write( n, base+1 ); // This sets the extension bit to zero
return bitsUsed;
}
else
{
size_t currentChunk = n & (numEncodings-1);
Write( currentChunk | numEncodings, base+1 );
n >>= base;
}
}
return bitsUsed;
}
//--------------------------------------------------------
// Signed quantities are encoded the same as unsigned
// The most relevant difference is that a number is considered
// to fit in base bits if the topmost bit of a base-long chunk
// matches the sign of the whole number
//--------------------------------------------------------
int EncodeVarLengthSigned( SSIZE_T n, int base )
{
_ASSERTE((base > 0) && (base < sizeof(SSIZE_T)*8));
size_t numEncodings = 1 << base;
for(int bitsUsed = base+1; ; bitsUsed += base+1)
{
size_t currentChunk = ((size_t) n) & (numEncodings-1);
size_t topmostBit = currentChunk & (numEncodings >> 1);
n >>= base; // signed arithmetic shift
if( topmostBit && (n == (SSIZE_T)-1) || !topmostBit && (n == 0))
{
// The topmost bit correctly represents the sign
Write( currentChunk, base+1 ); // This sets the extension bit to zero
return bitsUsed;
}
else
{
Write( currentChunk | numEncodings, base+1 );
}
}
}
private:
class MemoryBlockDesc
{
public:
size_t* StartAddress;
SLink m_Link;
inline void Init()
{
m_Link.m_pNext = NULL;
}
};
IJitAllocator* m_pAllocator;
size_t m_BitCount;
int m_FreeBitsInCurrentSlot;
SList<MemoryBlockDesc> m_MemoryBlocks;
const static int m_MemoryBlockSize = 512; // must be a multiple of the pointer size
size_t* m_pCurrentSlot; // bits are written through this pointer
size_t* m_OutOfBlockSlot; // sentinel value to determine when the block is full
#ifdef _DEBUG
int m_MemoryBlocksCount;
#endif
private:
// Writes bits knowing that they will all fit in the current memory slot
inline void WriteInCurrentSlot( size_t data, int count )
{
data &= SAFE_SHIFT_LEFT(1, count) - 1;
data <<= (sizeof( size_t )*8-m_FreeBitsInCurrentSlot);
*m_pCurrentSlot |= data;
}
void AllocMemoryBlock();
inline void InitCurrentSlot()
{
m_FreeBitsInCurrentSlot = sizeof( size_t )*8;
*m_pCurrentSlot = 0;
}
};
struct GcSlotDesc
{
union
{
UINT32 RegisterNumber;
GcStackSlot Stack;
} Slot;
unsigned IsRegister : 1;
unsigned IsInterior : 1;
unsigned IsPinned : 1;
};
typedef UINT32 GcSlotId;
class GcSlotSet
{
friend class GcInfoEncoder;
public:
GcSlotSet( GcInfoEncoder * pEncoder );
// Copy constructor
GcSlotSet( GcSlotSet & other );
inline void Add( GcSlotId slotId );
inline void Remove( GcSlotId slotId );
// Not used
#if 0
inline void RemoveAll();
void Add( GcSlotSet & other );
void Subtract( GcSlotSet & other );
void Intersect( GcSlotSet & other );
#endif
// Must be called when done with the object
inline void Dispose();
private:
// A bit vector representing the set
BYTE * m_Data;
int m_NumBytes;
GcInfoEncoder* m_pEncoder;
};
class GcInfoEncoder
{
public:
GcInfoEncoder(
ICorJitInfo* pCorJitInfo,
CORINFO_METHOD_INFO* pMethodInfo,
IJitAllocator* pJitAllocator
);
//------------------------------------------------------------------------
// Interruptibility
//------------------------------------------------------------------------
// An instruction at offset x will be interruptible
// if-and-only-if startInstructionOffset <= x < startInstructionOffset+length
void DefineInterruptibleRange( UINT32 startInstructionOffset, UINT32 length );
//------------------------------------------------------------------------
// Slot information
//------------------------------------------------------------------------
//
// spOffset are always relative to the SP of the caller (same as SP at the method entry and exit)
// Negative offsets describe GC refs in the local and outgoing areas.
// Positive offsets describe GC refs in the scratch area
// Note that if the dynamic allocation area is resized, the outgoing area will not be valid anymore
// Old slots must be declared dead and new ones can be defined.
// It's up to the JIT to do the right thing. We don't enforce this.
//
GcSlotId GetRegisterSlotId( UINT32 regNum, GcSlotFlags flags );
GcSlotId GetStackSlotId( INT32 spOffset, GcSlotFlags flags, GcStackSlotBase spBase = GC_CALLER_SP_REL );
//
// After a FinalizeSlotIds is called, no more slot definitions can be made.
// FinalizeSlotIds must be called once and only once before calling DefineGcStateAtCallSite
// If no call sites are described, calling FinalizeSlotIds can and should (for performance reasons) be avoided
//
void FinalizeSlotIds();
#if 0
#ifdef PARTIALLY_INTERRUPTIBLE_GC_SUPPORTED
//------------------------------------------------------------------------
// Partially-interruptible information
//------------------------------------------------------------------------
void DefineGcStateAtSafePoint(
UINT32 instructionOffset,
GcSlotSet &liveSlots
);
#endif // PARTIALLY_INTERRUPTIBLE_GC_SUPPORTED
#endif
//------------------------------------------------------------------------
// Fully-interruptible information
//------------------------------------------------------------------------
//
// For inputs, pass zero as offset
//
// This method defines what the GC state of a slot is when a thread's suspension IP
// is equal to instructionOffset
void SetSlotState( UINT32 instructionOffset,
GcSlotId slotId,
GcSlotState slotState
);
//------------------------------------------------------------------------
// Miscellaneous method information
//------------------------------------------------------------------------
void SetSecurityObjectStackSlot( INT32 spOffset );
void SetPSPSymStackSlot( INT32 spOffsetPSPSym );
void SetGenericsInstContextStackSlot( INT32 spOffsetGenericsContext );
void SetIsVarArg();
void SetCodeLength( UINT32 length );
// Optional in the general case. Required if the method uses GC_FRAMEREG_REL stack slots
void SetStackBaseRegister( UINT32 registerNumber );
void SetSizeOfEditAndContinuePreservedArea( UINT32 size );
#ifdef FIXED_STACK_PARAMETER_SCRATCH_AREA
void SetSizeOfStackOutgoingAndScratchArea( UINT32 size );
#endif // FIXED_STACK_PARAMETER_SCRATCH_AREA
//------------------------------------------------------------------------
// Encoding
//------------------------------------------------------------------------
//
// Build() encodes GC information into temporary buffers.
// The method description cannot change after Build is called
//
void Build();
//
// Write encoded information to its final destination and frees temporary buffers.
// The encoder shouldn't be used anymore after calling this method.
// It returns a pointer to the destination buffer, which address is byte-aligned
//
size_t GetByteCount();
BYTE* Emit(BYTE* dest);
private:
friend class LifetimeTransitionsQuickSort;
friend class LifetimeTransitionsQuickSortByOffset;
struct LifetimeTransition
{
UINT32 CodeOffset;
GcSlotDesc SlotDesc;
bool BecomesLive;
};
class LifetimeTransitionAllocator
{
public:
static void *Alloc (void *context, SIZE_T cb);
static void Free (void *context, void *pv);
};
ICorJitInfo* m_pCorJitInfo;
CORINFO_METHOD_INFO* m_pMethodInfo;
IJitAllocator* m_pAllocator;
#ifdef _DEBUG
char *m_MethodName, *m_ModuleName;
#endif
BitStreamWriter m_HeaderInfoWriter;
#if 0
#ifdef PARTIALLY_INTERRUPTIBLE_GC_SUPPORTED
BitStreamWriter m_PartiallyInterruptibleInfoWriter;
#endif
#endif
BitStreamWriter m_FullyInterruptibleInfoWriter;
StructArrayList<LifetimeTransition, 64, 2, LifetimeTransitionAllocator> m_LifetimeTransitions;
LifetimeTransition *m_rgSortedTransitions;
bool m_IsVarArg;
INT32 m_SecurityObjectStackSlot;
INT32 m_PSPSymStackSlot;
INT32 m_GenericsInstContextStackSlot;
UINT32 m_CodeLength;
UINT32 m_StackBaseRegister;
UINT32 m_SizeOfEditAndContinuePreservedArea;
UINT32 m_LastInterruptibleRangeStopOffset;
UINT32 m_NumInterruptibleRanges;
#ifdef FIXED_STACK_PARAMETER_SCRATCH_AREA
UINT32 m_SizeOfStackOutgoingAndScratchArea;
#endif // FIXED_STACK_PARAMETER_SCRATCH_AREA
void * eeAllocGCInfo (size_t blockSize);
inline int EncodeFullyInterruptibleSlotFlags(GcSlotDesc slotDesc)
{
int flagEnc = 1;
if( slotDesc.IsInterior )
flagEnc |= 0x2;
if( slotDesc.IsPinned )
flagEnc |= 0x4;
if(flagEnc == 1)
{
m_FullyInterruptibleInfoWriter.Write(0, 1);
return 1;
}
else
{
m_FullyInterruptibleInfoWriter.Write(flagEnc, 3);
return 3;
}
}
private:
friend class GcSlotSet;
friend class EncoderCheckState;
static const UINT32 m_MappingTableInitialSize = 32;
UINT32 m_MappingTableSize;
UINT32 m_NumSlotMappings;
GcSlotDesc *m_SlotMappings;
#if 0
#ifdef PARTIALLY_INTERRUPTIBLE_GC_SUPPORTED
UINT32 m_NumSafePointsWithGcState;
#endif
#endif
void GrowMappingTable();
#ifdef _DEBUG
bool m_IsMappingTableFrozen;
#endif
};
// Not used
#if 0
void GcSlotSet::RemoveAll()
{
ZeroMemory( m_Data, m_NumBytes );
}
#endif
void GcSlotSet::Dispose()
{
#ifdef MUST_CALL_JITALLOCATOR_FREE
m_pEncoder->m_pAllocator->Free( m_Data );
#endif
}
}
#endif // !__DBGGCINFOENCODER_H__
#endif // VERIFY_GCINFO
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