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gen-sframe.h revision 1.1 
      1 /* gen-sframe.h - Support for generating SFrame.
      2    Copyright (C) 2022-2024 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 /* SFrame Frame Row Entry (FRE).
     28 
     29    A frame row entry is a slice of the frame and can be valid for a set of
     30    program instructions.  It keeps all information needed to retrieve the CFA
     31    and the Return Address (RA) if tracked.
     32 
     33    A frame row entry effectively stores accumulated information gathered by
     34    interpreting multiple CFI instructions.  More precisely, it is a
     35    self-sufficient record in its own right.  Only the subset of information
     36    necessary for unwinding is stored: Given a PC, how to retrieve the CFA and
     37    the RA.
     38 */
     39 
     40 struct sframe_row_entry
     41 {
     42   /* A linked list.  */
     43   struct sframe_row_entry *next;
     44 
     45   /* Start and end of the frame row entry.  */
     46   symbolS *pc_begin;
     47   symbolS *pc_end;
     48 
     49   /* A frame row entry is a merge candidate if new information can be updated
     50      on it.  */
     51   bool merge_candidate;
     52 
     53   /* Whether the return address is mangled with pauth code.  */
     54   bool mangled_ra_p;
     55 
     56   /* Track CFA base (architectural) register ID.  */
     57   unsigned int cfa_base_reg;
     58   /* Offset from the CFA base register for recovering CFA.  */
     59   offsetT cfa_offset;
     60 
     61   /* Track the other register used as base register for CFA.  Specify whether
     62      it is in register or memory.  */
     63   unsigned int base_reg;
     64   unsigned int bp_loc;
     65   /* If the other register is stashed on stack, note the offset.  */
     66   offsetT bp_offset;
     67 
     68   /* Track RA location.  Specify whether it is in register or memory.  */
     69   unsigned int ra_loc;
     70   /* If RA is stashed on stack, note the offset.  */
     71   offsetT ra_offset;
     72 };
     73 
     74 /* SFrame Function Description Entry.  */
     75 
     76 struct sframe_func_entry
     77 {
     78   /* A linked list.  */
     79   struct sframe_func_entry *next;
     80 
     81   /* Reference to the FDE created from CFI in dw2gencfi.  Some information
     82      like the start_address and the segment is made available via this
     83      member.  */
     84   const struct fde_entry *dw_fde;
     85 
     86   /* Reference to the first FRE for this function.  */
     87   struct sframe_row_entry *sframe_fres;
     88 
     89   unsigned int num_fres;
     90 };
     91 
     92 /* SFrame Function Description Entry Translation Context.  */
     93 
     94 struct sframe_xlate_ctx
     95 {
     96   /* Reference to the FDE created from CFI in dw2gencfi.  Information
     97      like the FDE start_address, end_address and the cfi insns are
     98      made available via this member.  */
     99   const struct fde_entry *dw_fde;
    100 
    101   /* List of FREs in the current FDE translation context, bounded by first_fre
    102      and last_fre.  */
    103 
    104   /* Keep track of the first FRE for the purpose of restoring state if
    105      necessary (for DW_CFA_restore).  */
    106   struct sframe_row_entry *first_fre;
    107   /* The last FRE in the list.  */
    108   struct sframe_row_entry *last_fre;
    109 
    110   /* The current FRE under construction.  */
    111   struct sframe_row_entry *cur_fre;
    112   /* Remember FRE for an eventual restore.  */
    113   struct sframe_row_entry *remember_fre;
    114 
    115   unsigned num_xlate_fres;
    116 };
    117 
    118 /* Error codes for SFrame translation context.  */
    119 enum sframe_xlate_err
    120 {
    121   /* Success.  */
    122   SFRAME_XLATE_OK = 0,
    123   /* Error.  */
    124   SFRAME_XLATE_ERROR = 1,
    125   /* Detailed error codes.  */
    126   SFRAME_XLATE_ERR_INVAL = -1,
    127   SFRAME_XLATE_ERR_NOTREPRESENTED = -2,
    128 };
    129 
    130 /* Callback to create the abi/arch identifier for SFrame section.  */
    131 
    132 unsigned char
    133 sframe_get_abi_arch_callback (const char *target_arch,
    134 			      int big_endian_p);
    135 
    136 /* The list of all FDEs with data in SFrame internal representation.  */
    137 
    138 extern struct sframe_func_entry *all_sframe_fdes;
    139 
    140 /* SFrame version specific operations structure.  */
    141 
    142 struct sframe_version_ops
    143 {
    144   unsigned char format_version;    /* SFrame format version.  */
    145   /* set SFrame FRE info.  */
    146   unsigned char (*set_fre_info) (unsigned int, unsigned int, unsigned int,
    147 				 bool);
    148   /* set SFrame Func info.  */
    149   unsigned char (*set_func_info) (unsigned int, unsigned int, unsigned int);
    150 };
    151 
    152 /* Generate SFrame stack trace info and prepare contents for the output.
    153    outout_sframe ()  is called at the end of file.  */
    154 
    155 extern void output_sframe (segT sframe_seg);
    156 
    157 #endif /* GENSFRAME_H */
    158