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      1 /* gen-sframe.h - Support for generating SFrame.
      2    Copyright (C) 2022-2025 Free Software Foundation, Inc.
      3 
      4    This file is part of GAS, the GNU Assembler.
      5 
      6    GAS is free software; you can redistribute it and/or modify
      7    it under the terms of the GNU General Public License as published by
      8    the Free Software Foundation; either version 3, or (at your option)
      9    any later version.
     10 
     11    GAS is distributed in the hope that it will be useful,
     12    but WITHOUT ANY WARRANTY; without even the implied warranty of
     13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     14    GNU General Public License for more details.
     15 
     16    You should have received a copy of the GNU General Public License
     17    along with GAS; see the file COPYING.  If not, write to the Free
     18    Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
     19    02110-1301, USA.  */
     20 
     21 #ifndef GENSFRAME_H
     22 #define GENSFRAME_H
     23 
     24 #define SFRAME_FRE_ELEM_LOC_REG		0
     25 #define SFRAME_FRE_ELEM_LOC_STACK	1
     26 
     27 #define SFRAME_FRE_BASE_REG_INVAL	((unsigned int)-1)
     28 
     29 /* SFrame Frame Row Entry (FRE).
     30 
     31    A frame row entry is a slice of the frame and can be valid for a set of
     32    program instructions.  It keeps all information needed to retrieve the CFA
     33    and the Return Address (RA) if tracked.
     34 
     35    A frame row entry effectively stores accumulated information gathered by
     36    interpreting multiple CFI instructions.  More precisely, it is a
     37    self-sufficient record in its own right.  Only the subset of information
     38    necessary for unwinding is stored: Given a PC, how to retrieve the CFA and
     39    the RA.
     40 */
     41 
     42 struct sframe_row_entry
     43 {
     44   /* A linked list.  */
     45   struct sframe_row_entry *next;
     46 
     47   /* Start and end of the frame row entry.  */
     48   symbolS *pc_begin;
     49   symbolS *pc_end;
     50 
     51   /* A frame row entry is a merge candidate if new information can be updated
     52      on it.  */
     53   bool merge_candidate;
     54 
     55   /* Whether the return address is mangled with pauth code.  */
     56   bool mangled_ra_p;
     57 
     58   /* Track CFA base (architectural) register ID.  */
     59   unsigned int cfa_base_reg;
     60   /* Offset from the CFA base register for recovering CFA.  */
     61   offsetT cfa_offset;
     62 
     63   /* Track the other register used as base register for CFA.  Specify whether
     64      it is in register or memory.  */
     65   unsigned int base_reg;
     66   unsigned int bp_loc;
     67   /* If the other register is stashed on stack, note the offset.  */
     68   offsetT bp_offset;
     69 
     70   /* Track RA location.  Specify whether it is in register or memory.  */
     71   unsigned int ra_loc;
     72   /* If RA is stashed on stack, note the offset.  */
     73   offsetT ra_offset;
     74 };
     75 
     76 /* SFrame Function Description Entry.  */
     77 
     78 struct sframe_func_entry
     79 {
     80   /* A linked list.  */
     81   struct sframe_func_entry *next;
     82 
     83   /* Reference to the FDE created from CFI in dw2gencfi.  Some information
     84      like the start_address and the segment is made available via this
     85      member.  */
     86   const struct fde_entry *dw_fde;
     87 
     88   /* Reference to the first FRE for this function.  */
     89   struct sframe_row_entry *sframe_fres;
     90 
     91   unsigned int num_fres;
     92 };
     93 
     94 /* SFrame Function Description Entry Translation Context.  */
     95 
     96 struct sframe_xlate_ctx
     97 {
     98   /* Reference to the FDE created from CFI in dw2gencfi.  Information
     99      like the FDE start_address, end_address and the cfi insns are
    100      made available via this member.  */
    101   const struct fde_entry *dw_fde;
    102 
    103   /* List of FREs in the current FDE translation context, bounded by first_fre
    104      and last_fre.  */
    105 
    106   /* Keep track of the first FRE for the purpose of restoring state if
    107      necessary (for DW_CFA_restore).  */
    108   struct sframe_row_entry *first_fre;
    109   /* The last FRE in the list.  */
    110   struct sframe_row_entry *last_fre;
    111 
    112   /* The current FRE under construction.  */
    113   struct sframe_row_entry *cur_fre;
    114   /* Remember FRE for an eventual restore.  */
    115   struct sframe_row_entry *remember_fre;
    116 
    117   unsigned num_xlate_fres;
    118 };
    119 
    120 /* Error codes for SFrame translation context.  */
    121 enum sframe_xlate_err
    122 {
    123   /* Success.  */
    124   SFRAME_XLATE_OK = 0,
    125   /* Error.  */
    126   SFRAME_XLATE_ERROR = 1,
    127   /* Detailed error codes.  */
    128   SFRAME_XLATE_ERR_INVAL = -1,
    129   SFRAME_XLATE_ERR_NOTREPRESENTED = -2,
    130 };
    131 
    132 /* Callback to create the abi/arch identifier for SFrame section.  */
    133 
    134 unsigned char
    135 sframe_get_abi_arch_callback (const char *target_arch,
    136 			      int big_endian_p);
    137 
    138 /* SFrame version specific operations structure.  */
    139 
    140 struct sframe_version_ops
    141 {
    142   unsigned char format_version;    /* SFrame format version.  */
    143   /* set SFrame FRE info.  */
    144   unsigned char (*set_fre_info) (unsigned int, unsigned int, unsigned int,
    145 				 bool);
    146   /* set SFrame Func info.  */
    147   unsigned char (*set_func_info) (unsigned int, unsigned int, unsigned int);
    148 };
    149 
    150 /* Generate SFrame stack trace info and prepare contents for the output.
    151    outout_sframe ()  is called at the end of file.  */
    152 
    153 extern void output_sframe (segT sframe_seg);
    154 
    155 #endif /* GENSFRAME_H */
    156