xref: /external/libunwind/include/dwarf.h

/* libunwind - a platform-independent unwind library
   Copyright (c) 2003-2005 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

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#ifdef HAVE_ATOMIC_OPS_H
# include <atomic_ops.h>
#endif

#include <libunwind.h>

struct dwarf_cursor;	/* forward-declaration */

#include "dwarf-config.h"
#include <link.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_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;
extern struct mempool dwarf_cie_info_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];
    unw_word_t ip;		          /* ip this rs is for */
    unw_word_t ret_addr_column;           /* indicates which column in the rule table represents return address */
    unsigned short lru_chain;	  /* used for least-recently-used chain */
    unsigned short coll_chain;	/* used for hash collisions */
    unsigned short hint;	      /* hint for next rs to try (or -1) */
    unsigned short signal_frame; /* optional machine-dependent signal info */
  }
dwarf_reg_state_t;

typedef struct dwarf_cie_info
  {
    unw_word_t cie_instr_start;	/* start addr. of CIE "initial_instructions" */
    unw_word_t cie_instr_end;	/* end addr. of CIE "initial_instructions" */
    unw_word_t fde_instr_start;	/* start addr. of FDE "instructions" */
    unw_word_t fde_instr_end;	/* end addr. of FDE "instructions" */
    unw_word_t code_align;	/* code-alignment factor */
    unw_word_t data_align;	/* data-alignment factor */
    unw_word_t ret_addr_column;	/* column of return-address register */
    unw_word_t handler;		/* address of personality-routine */
    uint16_t abi;
    uint16_t tag;
    uint8_t fde_encoding;
    uint8_t lsda_encoding;
    unsigned int sized_augmentation : 1;
    unsigned int have_abi_marker : 1;
    unsigned int signal_frame : 1;
  }
dwarf_cie_info_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 */
    unw_word_t eh_args[UNW_TDEP_NUM_EH_REGS];
    unsigned int eh_valid_mask;

    dwarf_loc_t loc[DWARF_NUM_PRESERVED_REGS];

    unsigned int stash_frames :1; /* stash frames for fast lookup */
    unsigned int use_prev_instr :1; /* use previous (= call) or current (= signal) instruction? */
    unsigned int pi_valid :1;	/* is proc_info valid? */
    unsigned int pi_is_dynamic :1; /* proc_info found via dynamic proc info? */
    unw_proc_info_t pi;		/* info about current procedure */

    short hint; /* faster lookup of the rs cache */
    short prev_rs;
  }
dwarf_cursor_t;

#define DWARF_LOG_UNW_CACHE_SIZE	7
#define DWARF_UNW_CACHE_SIZE	(1 << DWARF_LOG_UNW_CACHE_SIZE)

#define DWARF_LOG_UNW_HASH_SIZE	(DWARF_LOG_UNW_CACHE_SIZE + 1)
#define DWARF_UNW_HASH_SIZE	(1 << DWARF_LOG_UNW_HASH_SIZE)

typedef unsigned char unw_hash_index_t;

struct dwarf_rs_cache
  {
    pthread_mutex_t lock;
    unsigned short lru_head;	/* index of lead-recently used rs */
    unsigned short lru_tail;	/* index of most-recently used rs */

    /* hash table that maps instruction pointer to rs index: */
    unsigned short hash[DWARF_UNW_HASH_SIZE];

    uint32_t generation;	/* generation number */

    /* rs cache: */
    dwarf_reg_state_t buckets[DWARF_UNW_CACHE_SIZE];
  };

/* A list of descriptors for loaded .debug_frame sections.  */

struct unw_debug_frame_list
  {
    /* The start (inclusive) and end (exclusive) of the described region.  */
    unw_word_t start;
    unw_word_t end;
    /* The debug frame itself.  */
    char *debug_frame;
    size_t debug_frame_size;
    /* Index (for binary search).  */
    struct table_entry *index;
    size_t index_size;
    /* Pointer to next descriptor.  */
    struct unw_debug_frame_list *next;
  };

struct dwarf_callback_data
  {
    /* in: */
    unw_word_t ip;		/* instruction-pointer we're looking for */
    unw_proc_info_t *pi;	/* proc-info pointer */
    int need_unwind_info;
    /* out: */
    int single_fde;		/* did we find a single FDE? (vs. a table) */
    unw_dyn_info_t di;		/* table info (if single_fde is false) */
    unw_dyn_info_t di_debug;	/* additional table info for .debug_frame */
  };

/* Convenience macros: */
#define dwarf_init			UNW_ARCH_OBJ (dwarf_init)
#define dwarf_callback			UNW_OBJ (dwarf_callback)
#define dwarf_find_proc_info		UNW_OBJ (dwarf_find_proc_info)
#define dwarf_find_debug_frame		UNW_OBJ (dwarf_find_debug_frame)
#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_extract_proc_info_from_fde \
		UNW_OBJ (dwarf_extract_proc_info_from_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_callback (struct dl_phdr_info *info, size_t size, void *ptr);
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_find_debug_frame (int found, unw_dyn_info_t *di_debug,
				 struct dl_phdr_info *info, unw_word_t ip);
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_extract_proc_info_from_fde (unw_addr_space_t as,
					     unw_accessors_t *a,
					     unw_word_t *fde_addr,
					     unw_proc_info_t *pi,
					     int need_unwind_info,
					     unw_word_t base,
					     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,
				       const unw_proc_info_t *pi,
				       unw_word_t *valp, void *arg);
extern int dwarf_step (struct dwarf_cursor *c);

#endif /* dwarf_h */