include/dwarf.h

/* libunwind - a platform-independent unwind library
   Copyright (c) 2003 Hewlett-Packard Development Company, L.P.
	Contributed by David Mosberger-Tang <davidm@hpl.hp.com>

This file is part of libunwind.

Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */

#ifndef dwarf_h
#define dwarf_h

#include "internal.h"
#include "mempool.h"

struct dwarf_cursor;	/* forward-declaration */

#include "dwarf-config.h"

/* DWARF expression opcodes.  */

typedef enum
  {
    DW_OP_addr			= 0x03,
    DW_OP_deref			= 0x06,
    DW_OP_const1u		= 0x08,
    DW_OP_const1s		= 0x09,
    DW_OP_const2u		= 0x0a,
    DW_OP_const2s		= 0x0b,
    DW_OP_const4u		= 0x0c,
    DW_OP_const4s		= 0x0d,
    DW_OP_const8u		= 0x0e,
    DW_OP_const8s		= 0x0f,
    DW_OP_constu		= 0x10,
    DW_OP_consts		= 0x11,
    DW_OP_dup			= 0x12,
    DW_OP_drop			= 0x13,
    DW_OP_over			= 0x14,
    DW_OP_pick			= 0x15,
    DW_OP_swap			= 0x16,
    DW_OP_rot			= 0x17,
    DW_OP_xderef		= 0x18,
    DW_OP_abs			= 0x19,
    DW_OP_and			= 0x1a,
    DW_OP_div			= 0x1b,
    DW_OP_minus			= 0x1c,
    DW_OP_mod			= 0x1d,
    DW_OP_mul			= 0x1e,
    DW_OP_neg			= 0x1f,
    DW_OP_not			= 0x20,
    DW_OP_or			= 0x21,
    DW_OP_plus			= 0x22,
    DW_OP_plus_uconst		= 0x23,
    DW_OP_shl			= 0x24,
    DW_OP_shr			= 0x25,
    DW_OP_shra			= 0x26,
    DW_OP_xor			= 0x27,
    DW_OP_skip			= 0x2f,
    DW_OP_bra			= 0x28,
    DW_OP_eq			= 0x29,
    DW_OP_ge			= 0x2a,
    DW_OP_gt			= 0x2b,
    DW_OP_le			= 0x2c,
    DW_OP_lt			= 0x2d,
    DW_OP_ne			= 0x2e,
    DW_OP_lit0			= 0x30,
    DW_OP_lit1,  DW_OP_lit2,  DW_OP_lit3,  DW_OP_lit4,  DW_OP_lit5,
    DW_OP_lit6,  DW_OP_lit7,  DW_OP_lit8,  DW_OP_lit9,  DW_OP_lit10,
    DW_OP_lit11, DW_OP_lit12, DW_OP_lit13, DW_OP_lit14, DW_OP_lit15,
    DW_OP_lit16, DW_OP_lit17, DW_OP_lit18, DW_OP_lit19, DW_OP_lit20,
    DW_OP_lit21, DW_OP_lit22, DW_OP_lit23, DW_OP_lit24, DW_OP_lit25,
    DW_OP_lit26, DW_OP_lit27, DW_OP_lit28, DW_OP_lit29, DW_OP_lit30,
    DW_OP_lit31,
    DW_OP_reg0			= 0x50,
    DW_OP_reg1,  DW_OP_reg2,  DW_OP_reg3,  DW_OP_reg4,  DW_OP_reg5,
    DW_OP_reg6,  DW_OP_reg7,  DW_OP_reg8,  DW_OP_reg9,  DW_OP_reg10,
    DW_OP_reg11, DW_OP_reg12, DW_OP_reg13, DW_OP_reg14, DW_OP_reg15,
    DW_OP_reg16, DW_OP_reg17, DW_OP_reg18, DW_OP_reg19, DW_OP_reg20,
    DW_OP_reg21, DW_OP_reg22, DW_OP_reg23, DW_OP_reg24, DW_OP_reg25,
    DW_OP_reg26, DW_OP_reg27, DW_OP_reg28, DW_OP_reg29, DW_OP_reg30,
    DW_OP_reg31,
    DW_OP_breg0			= 0x70,
    DW_OP_breg1,  DW_OP_breg2,  DW_OP_breg3,  DW_OP_breg4,  DW_OP_breg5,
    DW_OP_breg6,  DW_OP_breg7,  DW_OP_breg8,  DW_OP_breg9,  DW_OP_breg10,
    DW_OP_breg11, DW_OP_breg12, DW_OP_breg13, DW_OP_breg14, DW_OP_breg15,
    DW_OP_breg16, DW_OP_breg17, DW_OP_breg18, DW_OP_breg19, DW_OP_breg20,
    DW_OP_breg21, DW_OP_breg22, DW_OP_breg23, DW_OP_breg24, DW_OP_breg25,
    DW_OP_breg26, DW_OP_breg27, DW_OP_breg28, DW_OP_breg29, DW_OP_breg30,
    DW_OP_breg31,
    DW_OP_regx			= 0x90,
    DW_OP_fbreg			= 0x91,
    DW_OP_bregx			= 0x92,
    DW_OP_piece			= 0x93,
    DW_OP_deref_size		= 0x94,
    DW_OP_xderef_size		= 0x95,
    DW_OP_nop			= 0x96,
    DW_OP_push_object_address	= 0x97,
    DW_OP_call2			= 0x98,
    DW_OP_call4			= 0x99,
    DW_OP_call_ref		= 0x9a,
    DW_OP_lo_user		= 0xe0,
    DW_OP_hi_user		= 0xff
  }
dwarf_expr_op_t;

#define DWARF_CIE_VERSION	3	/* GCC emits version 1??? */

#define DWARF_CFA_OPCODE_MASK	0xc0
#define DWARF_CFA_OPERAND_MASK	0x3f

typedef enum
  {
    DW_CFA_advance_loc		= 0x40,
    DW_CFA_offset		= 0x80,
    DW_CFA_restore		= 0xc0,
    DW_CFA_nop			= 0x00,
    DW_CFA_set_loc		= 0x01,
    DW_CFA_advance_loc1		= 0x02,
    DW_CFA_advance_loc2		= 0x03,
    DW_CFA_advance_loc4		= 0x04,
    DW_CFA_offset_extended	= 0x05,
    DW_CFA_restore_extended	= 0x06,
    DW_CFA_undefined		= 0x07,
    DW_CFA_same_value		= 0x08,
    DW_CFA_register		= 0x09,
    DW_CFA_remember_state	= 0x0a,
    DW_CFA_restore_state	= 0x0b,
    DW_CFA_def_cfa		= 0x0c,
    DW_CFA_def_cfa_register	= 0x0d,
    DW_CFA_def_cfa_offset	= 0x0e,
    DW_CFA_def_cfa_expression	= 0x0f,
    DW_CFA_CFA_expression	= 0x10,
    DW_CFA_offset_extended_sf	= 0x11,
    DW_CFA_def_cfa_sf		= 0x12,
    DW_CFA_def_cfa_offset_sf	= 0x13,
    DW_CFA_lo_user		= 0x1c,
    DW_CFA_MIPS_advance_loc8	= 0x1d,
    DW_CFA_GNU_window_save	= 0x2d,
    DW_CFA_GNU_args_size	= 0x2e,
    DW_CFA_GNU_negative_offset_extended	= 0x2f,
    DW_CFA_hi_user		= 0x3c
  }
dwarf_cfa_t;

/* DWARF Pointer-Encoding (PEs).

   Pointer-Encodings were invented for the GCC exception-handling
   support for C++, but they represent a rather generic way of
   describing the format in which an address/pointer is stored and
   hence we include the definitions here, in the main dwarf.h file.
   The Pointer-Encoding format is partially documented in Linux Base
   Spec v1.3 (http://www.linuxbase.org/spec/).  The rest is reverse
   engineered from GCC.

*/
#define DW_EH_PE_FORMAT_MASK	0x0f	/* format of the encoded value */
#define DW_EH_PE_APPL_MASK	0x70	/* how the value is to be applied */
/* Flag bit.  If set, the resulting pointer is the address of the word
   that contains the final address.  */
#define DW_EH_PE_indirect	0x80

/* Pointer-encoding formats: */
#define DW_EH_PE_omit		0xff
#define DW_EH_PE_ptr		0x00	/* pointer-sized unsigned value */
#define DW_EH_PE_uleb128	0x01	/* unsigned LE base-128 value */
#define DW_EH_PE_udata2		0x02	/* unsigned 16-bit value */
#define DW_EH_PE_udata4		0x03	/* unsigned 32-bit value */
#define DW_EH_PE_udata8		0x04	/* unsigned 64-bit value */
#define DW_EH_PE_sleb128	0x09	/* signed LE base-128 value */
#define DW_EH_PE_sdata2		0x0a	/* signed 16-bit value */
#define DW_EH_PE_sdata4		0x0b	/* signed 32-bit value */
#define DW_EH_PE_sdata8		0x0c	/* signed 64-bit value */

/* Pointer-encoding application: */
#define DW_EH_PE_absptr		0x00	/* absolute value */
#define DW_EH_PE_pcrel		0x10	/* rel. to addr. of encoded value */
#define DW_EH_PE_textrel	0x20	/* text-relative (GCC-specific???) */
#define DW_EH_PE_datarel	0x30	/* data-relative */
/* The following are not documented by LSB v1.3, yet they are used by
   GCC, presumably they aren't documented by LSB since they aren't
   used on Linux:  */
#define DW_EH_PE_funcrel	0x40	/* start-of-procedure-relative */
#define DW_EH_PE_aligned	0x50	/* aligned pointer */

extern struct mempool dwarf_reg_state_pool;

typedef enum
  {
    DWARF_WHERE_UNDEF,		/* register isn't saved at all */
    DWARF_WHERE_SAME,		/* register has same value as in prev. frame */
    DWARF_WHERE_CFAREL,		/* register saved at CFA-relative address */
    DWARF_WHERE_REG,		/* register saved in another register */
    DWARF_WHERE_EXPR,		/* register saved */
  }
dwarf_where_t;

typedef struct
  {
    dwarf_where_t where;	/* how is the register saved? */
    unw_word_t val;		/* where it's saved */
  }
dwarf_save_loc_t;

/* For uniformity, we'd like to treat the CFA save-location like any
   other register save-location, but this doesn't quite work, because
   the CFA can be expressed as a (REGISTER,OFFSET) pair.  To handle
   this, we use two dwarf_save_loc structures to describe the CFA.
   The first one (CFA_REG_COLUMN), tells us where the CFA is saved.
   In the case of DWARF_WHERE_EXPR, the CFA is defined by a DWARF
   location expression whose address is given by member "val".  In the
   case of DWARF_WHERE_REG, member "val" gives the number of the
   base-register and the "val" member of DWARF_CFA_OFF_COLUMN gives
   the offset value.  */
#define DWARF_CFA_REG_COLUMN	DWARF_NUM_PRESERVED_REGS
#define DWARF_CFA_OFF_COLUMN	(DWARF_NUM_PRESERVED_REGS + 1)

typedef struct dwarf_reg_state
  {
    struct dwarf_reg_state *next;	/* for rs_stack */
    dwarf_save_loc_t reg[DWARF_NUM_PRESERVED_REGS + 2];
  }
dwarf_reg_state_t;

typedef struct dwarf_state_record
  {
    unsigned char fde_encoding;
    unw_word_t args_size;

    dwarf_reg_state_t rs_initial;	/* reg-state after CIE instructions */
    dwarf_reg_state_t rs_current;	/* current reg-state */
  }
dwarf_state_record_t;

typedef struct dwarf_cursor
  {
    void *as_arg;		/* argument to address-space callbacks */
    unw_addr_space_t as;	/* reference to per-address-space info */

    unw_word_t cfa;	/* canonical frame address; aka frame-/stack-pointer */
    unw_word_t ip;		/* instruction pointer */
    unw_word_t args_size;	/* size of arguments */
    unw_word_t ret_addr_column;	/* column for return-address */

    dwarf_loc_t loc[DWARF_NUM_PRESERVED_REGS];

    unsigned int pi_valid :1;	/* is proc_info valid? */
    unsigned int pi_is_dynamic :1; /* proc_info found via dynamic proc info? */
    unsigned int cfa_is_sp :1;	/* TRUE if stack-pointer is CFA */
    unw_proc_info_t pi;		/* info about current procedure */
  }
dwarf_cursor_t;

/* Convenience macros: */
#define dwarf_init			UNW_ARCH_OBJ (dwarf_init)
#define dwarf_find_proc_info		UNW_OBJ (dwarf_find_proc_info)
#define dwarf_search_unwind_table	UNW_OBJ (dwarf_search_unwind_table)
#define dwarf_put_unwind_info		UNW_OBJ (dwarf_put_unwind_info)
#define dwarf_put_unwind_info		UNW_OBJ (dwarf_put_unwind_info)
#define dwarf_eval_expr			UNW_OBJ (dwarf_eval_expr)
#define dwarf_parse_fde			UNW_OBJ (dwarf_parse_fde)
#define dwarf_find_save_locs		UNW_OBJ (dwarf_find_save_locs)
#define dwarf_create_state_record	UNW_OBJ (dwarf_create_state_record)
#define dwarf_make_proc_info		UNW_OBJ (dwarf_make_proc_info)
#define dwarf_read_encoded_pointer	UNW_OBJ (dwarf_read_encoded_pointer)
#define dwarf_step			UNW_OBJ (dwarf_step)

extern int dwarf_init (void);
extern int dwarf_find_proc_info (unw_addr_space_t as, unw_word_t ip,
				 unw_proc_info_t *pi,
				 int need_unwind_info, void *arg);
extern int dwarf_search_unwind_table (unw_addr_space_t as,
				      unw_word_t ip,
				      unw_dyn_info_t *di,
				      unw_proc_info_t *pi,
				      int need_unwind_info, void *arg);
extern void dwarf_put_unwind_info (unw_addr_space_t as,
				   unw_proc_info_t *pi, void *arg);
extern int dwarf_eval_expr (struct dwarf_cursor *c, unw_word_t *addr,
			    unw_word_t len, unw_word_t *valp,
			    int *is_register);
extern int dwarf_parse_fde (unw_addr_space_t as, unw_accessors_t *a,
			    unw_word_t *addr, unw_proc_info_t *pi,
			    unw_dyn_dwarf_fde_info_t *dfi, void *arg);
extern int dwarf_find_save_locs (struct dwarf_cursor *c);
extern int dwarf_create_state_record (struct dwarf_cursor *c,
				      dwarf_state_record_t *sr);
extern int dwarf_make_proc_info (struct dwarf_cursor *c);
extern int dwarf_read_encoded_pointer (unw_addr_space_t as,
				       unw_accessors_t *a,
				       unw_word_t *addr,
				       unsigned char encoding,
				       unw_proc_info_t *pi,
				       unw_word_t *valp, void *arg);
extern int dwarf_step (struct dwarf_cursor *c);

#endif /* dwarf_h */