mono/mini/mini-unwind.h

   1 /*
   2  * mini-unwind.h: Stack Unwinding Interface
   3  *
   4  * Authors:
   5  *   Zoltan Varga (vargaz@gmail.com)
   6  *
   7  * (C) 2007 Novell, Inc.
   8  */
   9
  10 #ifndef __MONO_UNWIND_H__
  11 #define __MONO_UNWIND_H__
  12
  13 #include "mini.h"
  14
  15 /*
  16  * This is a platform-independent interface for unwinding through stack frames
  17  * based on the Dwarf unwinding interface.
  18  * See http://dwarfstd.org/Dwarf3.pdf, section "Call Frame Information".
  19  */
  20
  21 /*
  22  * CFA = Canonical Frame Address. By convention, this is the value of the stack pointer
  23  * prior to the execution of the call instruction in the caller. I.e. on x86, it is
  24  * esp + 4 on entry to a function. The value of the CFA does not change during execution
  25  * of a function. There are two kinds of unwind directives:
  26  * - those that describe how to compute the CFA at a given pc offset inside a function
  27  * - those that describe where a given register is saved relative to the CFA.
  28  */
  29
  30 /* Unwind ops */
  31
  32 /* The low 6 bits contain additional information */
  33 #define DW_CFA_advance_loc        0x40
  34 #define DW_CFA_offset             0x80
  35 #define DW_CFA_restore            0xc0
  36
  37 #define DW_CFA_nop              0x00
  38 #define DW_CFA_set_loc          0x01
  39 #define DW_CFA_advance_loc1     0x02
  40 #define DW_CFA_advance_loc2     0x03
  41 #define DW_CFA_advance_loc4     0x04
  42 #define DW_CFA_offset_extended  0x05
  43 #define DW_CFA_restore_extended 0x06
  44 #define DW_CFA_undefined        0x07
  45 #define DW_CFA_same_value       0x08
  46 #define DW_CFA_register         0x09
  47 #define DW_CFA_remember_state   0x0a
  48 #define DW_CFA_restore_state    0x0b
  49 #define DW_CFA_def_cfa          0x0c
  50 #define DW_CFA_def_cfa_register 0x0d
  51 #define DW_CFA_def_cfa_offset   0x0e
  52 #define DW_CFA_def_cfa_expression 0x0f
  53 #define DW_CFA_expression       0x10
  54 #define DW_CFA_offset_extended_sf 0x11
  55 #define DW_CFA_def_cfa_sf       0x12
  56 #define DW_CFA_def_cfa_offset_sf 0x13
  57 #define DW_CFA_val_offset        0x14
  58 #define DW_CFA_val_offset_sf     0x15
  59 #define DW_CFA_val_expression    0x16
  60 #define DW_CFA_lo_user           0x1c
  61 #define DW_CFA_hi_user           0x3f
  62
  63 /* Represents one unwind instruction */
  64 typedef struct {
  65         guint8 op; /* One of DW_CFA_... */
  66         guint16 reg; /* register number in the hardware encoding */
  67         gint32 val; /* arbitrary value */
  68         guint32 when; /* The offset _after_ the cpu instruction this unwind op belongs to */
  69 } MonoUnwindOp;
  70
  71 /*
  72  * Macros for emitting MonoUnwindOp structures.
  73  * These should be called _after_ emitting the cpu instruction the unwind op
  74  * belongs to.
  75  */
  76
  77 /* Set cfa to reg+offset */
  78 #define mono_emit_unwind_op_def_cfa(cfg,ip,reg,offset) do { mono_emit_unwind_op (cfg, (ip) - (cfg)->native_code, DW_CFA_def_cfa, (reg), (offset)); (cfg)->cfa_reg = (reg); (cfg)->cfa_offset = (offset); } while (0)
  79 /* Set cfa to reg+existing offset */
  80 #define mono_emit_unwind_op_def_cfa_reg(cfg,ip,reg) do { mono_emit_unwind_op (cfg, (ip) - (cfg)->native_code, DW_CFA_def_cfa_register, (reg), (0)); (cfg)->cfa_reg = (reg); } while (0)
  81 /* Set cfa to existing reg+offset */
  82 #define mono_emit_unwind_op_def_cfa_offset(cfg,ip,offset) do { mono_emit_unwind_op (cfg, (ip) - (cfg)->native_code, DW_CFA_def_cfa_offset, (0), (offset)); (cfg)->cfa_offset = (offset); } while (0)
  83 /* Reg is the same as it was on enter to the function */
  84 #define mono_emit_unwind_op_same_value(cfg,ip,reg) mono_emit_unwind_op (cfg, (ip) - (cfg)->native_code, DW_CFA_same_value, (reg), 0)
  85 /* Reg is saved at cfa+offset */
  86 #define mono_emit_unwind_op_offset(cfg,ip,reg,offset) mono_emit_unwind_op (cfg, (ip) - (cfg)->native_code, DW_CFA_offset, (reg), (offset))
  87
  88 /* Similar macros usable when a cfg is not available, like for trampolines */
  89 #define mono_add_unwind_op_def_cfa(op_list,code,buf,reg,offset) do { (op_list) = g_slist_append ((op_list), mono_create_unwind_op ((code) - (buf), DW_CFA_def_cfa, (reg), (offset))); } while (0)
  90 #define mono_add_unwind_op_def_cfa_reg(op_list,code,buf,reg) do { (op_list) = g_slist_append ((op_list), mono_create_unwind_op ((code) - (buf), DW_CFA_def_cfa_register, (reg), (0))); } while (0)
  91 #define mono_add_unwind_op_def_cfa_offset(op_list,code,buf,offset) do { (op_list) = g_slist_append ((op_list), mono_create_unwind_op ((code) - (buf), DW_CFA_def_cfa_offset, 0, (offset))); } while (0)
  92 #define mono_add_unwind_op_same_value(op_list,code,buf,reg) do { (op_list) = g_slist_append ((op_list), mono_create_unwind_op ((code) - (buf), DW_CFA_same_value, (reg), 0)); } while (0)
  93 #define mono_add_unwind_op_offset(op_list,code,buf,reg,offset) do { (op_list) = g_slist_append ((op_list), mono_create_unwind_op ((code) - (buf), DW_CFA_offset, (reg), (offset))); } while (0)
  94
  95 /* Pointer Encoding in the .eh_frame */
  96 enum {
  97         DW_EH_PE_absptr = 0x00,
  98         DW_EH_PE_omit = 0xff,
  99
 100         DW_EH_PE_udata4 = 0x03,
 101         DW_EH_PE_sdata4 = 0x0b,
 102         DW_EH_PE_sdata8 = 0x0c,
 103
 104         DW_EH_PE_pcrel = 0x10,
 105         DW_EH_PE_textrel = 0x20,
 106         DW_EH_PE_datarel = 0x30,
 107         DW_EH_PE_funcrel = 0x40,
 108         DW_EH_PE_aligned = 0x50,
 109
 110         DW_EH_PE_indirect = 0x80
 111 };
 112
 113 int
 114 mono_hw_reg_to_dwarf_reg (int reg) MONO_INTERNAL;
 115
 116 int
 117 mono_dwarf_reg_to_hw_reg (int reg) MONO_INTERNAL;
 118
 119 int
 120 mono_unwind_get_dwarf_data_align (void) MONO_INTERNAL;
 121
 122 int
 123 mono_unwind_get_dwarf_pc_reg (void) MONO_INTERNAL;
 124
 125 guint8*
 126 mono_unwind_ops_encode (GSList *unwind_ops, guint32 *out_len) MONO_INTERNAL;
 127
 128 void
 129 mono_unwind_frame (guint8 *unwind_info, guint32 unwind_info_len,
 130                                    guint8 *start_ip, guint8 *end_ip, guint8 *ip, mgreg_t *regs, int nregs,
 131                                    mgreg_t **save_locations, int save_locations_len,
 132                                    guint8 **out_cfa) MONO_INTERNAL;
 133
 134 void mono_unwind_init (void) MONO_INTERNAL;
 135
 136 void mono_unwind_cleanup (void) MONO_INTERNAL;
 137
 138 guint32 mono_cache_unwind_info (guint8 *unwind_info, guint32 unwind_info_len) MONO_INTERNAL;
 139
 140 guint8* mono_get_cached_unwind_info (guint32 index, guint32 *unwind_info_len) MONO_INTERNAL;
 141
 142 guint8* mono_unwind_decode_fde (guint8 *fde, guint32 *out_len, guint32 *code_len, MonoJitExceptionInfo **ex_info, guint32 *ex_info_len, gpointer **type_info, int *this_reg, int *this_offset) MONO_LLVM_INTERNAL;
 143
 144 /* Data retrieved from an LLVM Mono FDE entry */
 145 typedef struct {
 146         /* Malloc'ed */
 147         guint8 *unw_info;
 148         guint32 unw_info_len;
 149         MonoJitExceptionInfo *ex_info;
 150         guint32 ex_info_len;
 151         gpointer *type_info;
 152         int this_reg;
 153         int this_offset;
 154 } MonoLLVMFDEInfo;
 155
 156 void
 157 mono_unwind_decode_llvm_mono_fde (guint8 *fde, int fde_len, guint8 *cie, guint8 *code, MonoLLVMFDEInfo *res) MONO_INTERNAL;
 158
 159 GSList* mono_unwind_get_cie_program (void) MONO_INTERNAL;
 160
 161 #endif