/***************************************************************************
 * ARM Stack Unwinder, Michael.McTernan.2001@cs.bris.ac.uk
 *
 * This program is PUBLIC DOMAIN.
 * This means that there is no copyright and anyone is able to take a copy
 * for free and use it as they wish, with or without modifications, and in
 * any context, commerically or otherwise. The only limitation is that I
 * don't guarantee that the software is fit for any purpose or accept any
 * liablity for it's use or misuse - this software is without warranty.
 ***************************************************************************
 * File Description: Internal interface between the ARM unwinding sub-modules.
 **************************************************************************/

#ifndef UNWARM_H
#define UNWARM_H

/***************************************************************************
 * Nested Include Files
 **************************************************************************/

#include "types.h"
#include "unwarminder.h"

/***************************************************************************
 * Manifest Constants
 **************************************************************************/

/** The maximum number of instructions to interpet in a function.
 * Unwinding will be unconditionally stopped and UNWIND_EXHAUSTED returned
 * if more than this number of instructions are interpreted in a single
 * function without unwinding a stack frame.  This prevents infinite loops
 * or corrupted program memory from preventing unwinding from progressing.
 */
#define UNW_MAX_INSTR_COUNT 1000 /* originaly it was 100 */

/** The size of the hash used to track reads and writes to memory.
 * This should be a prime value for efficiency.
 */
#define MEM_HASH_SIZE        61 /* originaly it was 31 */

/***************************************************************************
 * Type Definitions
 **************************************************************************/

typedef enum
{
    /** Invalid value. */
    REG_VAL_INVALID      = 0x00,
    REG_VAL_FROM_STACK   = 0x01,
    REG_VAL_FROM_MEMORY  = 0x02,
    REG_VAL_FROM_CONST   = 0x04,
    REG_VAL_ARITHMETIC   = 0x80
}
RegValOrigin;


/** Type for tracking information about a register.
 * This stores the register value, as well as other data that helps unwinding.
 */
typedef struct
{
    /** The value held in the register. */
    Int32              v;

    /** The origin of the register value.
     * This is used to track how the value in the register was loaded.
     */
    RegValOrigin       o;
}
RegData;


/** Structure used to track reads and writes to memory.
 * This structure is used as a hash to store a small number of writes
 * to memory.
 */
typedef struct
{
    /** Memory contents. */
    Int32              v[MEM_HASH_SIZE];

    /** Address at which v[n] represents. */
    Int32              a[MEM_HASH_SIZE];

    /** Indicates whether the data in v[n] and a[n] is occupied.
     * Each bit represents one hash value.
     */
    Int8               used[(MEM_HASH_SIZE + 7) / 8];

    /** Indicates whether the data in v[n] is valid.
     * This allows a[n] to be set, but for v[n] to be marked as invalid.
     * Specifically this is needed for when an untracked register value
     * is written to memory.
     */
    Int8               tracked[(MEM_HASH_SIZE + 7) / 8];
}
MemData;


/** Structure that is used to keep track of unwinding meta-data.
 * This data is passed between all the unwinding functions.
 */
typedef struct
{
    /** The register values and meta-data. */
    RegData regData[16];

    /** Memory tracking data. */
    MemData memData;

    /** Pointer to the callback functions */
    const UnwindCallbacks *cb;

    /** Pointer to pass to the report function. */
    const void *reportData;
}
UnwState;

/***************************************************************************
 *  Macros
 **************************************************************************/

#define M_IsOriginValid(v) (((v) & 0x7f) ? TRUE : FALSE)
#define M_Origin2Str(v)    ((v) ? "VALID" : "INVALID")

#if defined(UNW_DEBUG)
#define UnwPrintd1(a)               state->cb->printf(a)
#define UnwPrintd2(a,b)             state->cb->printf(a,b)
#define UnwPrintd3(a,b,c)           state->cb->printf(a,b,c)
#define UnwPrintd4(a,b,c,d)         state->cb->printf(a,b,c,d)
#define UnwPrintd5(a,b,c,d,e)       state->cb->printf(a,b,c,d,e)
#define UnwPrintd6(a,b,c,d,e,f)     state->cb->printf(a,b,c,d,e,f)
#define UnwPrintd7(a,b,c,d,e,f,g)   state->cb->printf(a,b,c,d,e,f,g)
#define UnwPrintd8(a,b,c,d,e,f,g,h) state->cb->printf(a,b,c,d,e,f,g,h)
#else
#define UnwPrintd1(a)
#define UnwPrintd2(a,b)
#define UnwPrintd3(a,b,c)
#define UnwPrintd4(a,b,c,d)
#define UnwPrintd5(a,b,c,d,e)
#define UnwPrintd6(a,b,c,d,e,f)
#define UnwPrintd7(a,b,c,d,e,f,g)
#define UnwPrintd8(a,b,c,d,e,f,g,h)
#endif

/***************************************************************************
 *  Function Prototypes
 **************************************************************************/

UnwResult UnwStartArm       (UnwState * const state);

UnwResult UnwStartThumb     (UnwState * const state);

void UnwInvalidateRegisterFile(RegData *regFile);

void UnwInitState           (UnwState * const       state,
                             const UnwindCallbacks *cb,
                             void                  *rptData,
                             Int32                  pcValue,
                             Int32                  spValue);

Boolean UnwReportRetAddr    (UnwState * const state, Int32 addr);

Boolean UnwMemWriteRegister (UnwState * const      state,
                             const Int32           addr,
                             const RegData * const reg);

Boolean UnwMemReadRegister  (UnwState * const      state,
                             const Int32           addr,
                             RegData * const       reg);

void    UnwMemHashGC        (UnwState * const state);

#endif /* UNWARM_H */

/* END OF FILE */