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-rw-r--r--gcc/frame-dwarf2.c778
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diff --git a/gcc/frame-dwarf2.c b/gcc/frame-dwarf2.c
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-/* Subroutines needed for unwinding DWARF 2 format stack frame info
- for exception handling. */
-/* Compile this one with gcc. */
-/* Copyright (C) 1997, 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
- Contributed by Jason Merrill <jason@cygnus.com>.
-
-This file is part of GNU CC.
-
-GNU CC is free software; you can redistribute it and/or modify
-it under the terms of the GNU General Public License as published by
-the Free Software Foundation; either version 2, or (at your option)
-any later version.
-
-In addition to the permissions in the GNU General Public License, the
-Free Software Foundation gives you unlimited permission to link the
-compiled version of this file into combinations with other programs,
-and to distribute those combinations without any restriction coming
-from the use of this file. (The General Public License restrictions
-do apply in other respects; for example, they cover modification of
-the file, and distribution when not linked into a combine
-executable.)
-
-GNU CC is distributed in the hope that it will be useful,
-but WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-GNU General Public License for more details.
-
-You should have received a copy of the GNU General Public License
-along with GNU CC; see the file COPYING. If not, write to
-the Free Software Foundation, 59 Temple Place - Suite 330,
-Boston, MA 02111-1307, USA. */
-
-/* It is incorrect to include config.h here, because this file is being
- compiled for the target, and hence definitions concerning only the host
- do not apply. */
-
-#include "tconfig.h"
-#include "tsystem.h"
-
-#ifdef DWARF2_UNWIND_INFO
-#include "dwarf2.h"
-#include "frame.h"
-#include "gthr.h"
-
-#ifdef __GTHREAD_MUTEX_INIT
-static __gthread_mutex_t object_mutex = __GTHREAD_MUTEX_INIT;
-#else
-static __gthread_mutex_t object_mutex;
-#endif
-
-/* Don't use `fancy_abort' here even if config.h says to use it. */
-#ifdef abort
-#undef abort
-#endif
-
-/* Some types used by the DWARF 2 spec. */
-
-typedef int sword __attribute__ ((mode (SI)));
-typedef unsigned int uword __attribute__ ((mode (SI)));
-typedef unsigned int uaddr __attribute__ ((mode (pointer)));
-typedef int saddr __attribute__ ((mode (pointer)));
-typedef unsigned char ubyte;
-
-/* Terminology:
- CIE - Common Information Element
- FDE - Frame Descriptor Element
-
- There is one per function, and it describes where the function code
- is located, and what the register lifetimes and stack layout are
- within the function.
-
- The data structures are defined in the DWARF specfication, although
- not in a very readable way (see LITERATURE).
-
- Every time an exception is thrown, the code needs to locate the FDE
- for the current function, and starts to look for exception regions
- from that FDE. This works in a two-level search:
- a) in a linear search, find the shared image (i.e. DLL) containing
- the PC
- b) using the FDE table for that shared object, locate the FDE using
- binary search (which requires the sorting). */
-
-/* The first few fields of a CIE. The CIE_id field is 0 for a CIE,
- to distinguish it from a valid FDE. FDEs are aligned to an addressing
- unit boundary, but the fields within are unaligned. */
-
-struct dwarf_cie {
- uword length;
- sword CIE_id;
- ubyte version;
- char augmentation[0];
-} __attribute__ ((packed, aligned (__alignof__ (void *))));
-
-/* The first few fields of an FDE. */
-
-struct dwarf_fde {
- uword length;
- sword CIE_delta;
- void* pc_begin;
- uaddr pc_range;
-} __attribute__ ((packed, aligned (__alignof__ (void *))));
-
-typedef struct dwarf_fde fde;
-
-/* Objects to be searched for frame unwind info. */
-
-static struct object *objects;
-
-/* The information we care about from a CIE. */
-
-struct cie_info {
- char *augmentation;
- void *eh_ptr;
- int code_align;
- int data_align;
- unsigned ra_regno;
-};
-
-/* The current unwind state, plus a saved copy for DW_CFA_remember_state. */
-
-struct frame_state_internal
-{
- struct frame_state s;
- struct frame_state_internal *saved_state;
-};
-
-/* This is undefined below if we need it to be an actual function. */
-#define init_object_mutex_once()
-
-#if __GTHREADS
-#ifdef __GTHREAD_MUTEX_INIT_FUNCTION
-
-/* Helper for init_object_mutex_once. */
-
-static void
-init_object_mutex (void)
-{
- __GTHREAD_MUTEX_INIT_FUNCTION (&object_mutex);
-}
-
-/* Call this to arrange to initialize the object mutex. */
-
-#undef init_object_mutex_once
-static void
-init_object_mutex_once (void)
-{
- static __gthread_once_t once = __GTHREAD_ONCE_INIT;
- __gthread_once (&once, init_object_mutex);
-}
-
-#endif /* __GTHREAD_MUTEX_INIT_FUNCTION */
-#endif /* __GTHREADS */
-
-/* Decode the unsigned LEB128 constant at BUF into the variable pointed to
- by R, and return the new value of BUF. */
-
-static void *
-decode_uleb128 (unsigned char *buf, unsigned *r)
-{
- unsigned shift = 0;
- unsigned result = 0;
-
- while (1)
- {
- unsigned byte = *buf++;
- result |= (byte & 0x7f) << shift;
- if ((byte & 0x80) == 0)
- break;
- shift += 7;
- }
- *r = result;
- return buf;
-}
-
-/* Decode the signed LEB128 constant at BUF into the variable pointed to
- by R, and return the new value of BUF. */
-
-static void *
-decode_sleb128 (unsigned char *buf, int *r)
-{
- unsigned shift = 0;
- unsigned result = 0;
- unsigned byte;
-
- while (1)
- {
- byte = *buf++;
- result |= (byte & 0x7f) << shift;
- shift += 7;
- if ((byte & 0x80) == 0)
- break;
- }
- if (shift < (sizeof (*r) * 8) && (byte & 0x40) != 0)
- result |= - (1 << shift);
-
- *r = result;
- return buf;
-}
-
-/* Read unaligned data from the instruction buffer. */
-
-union unaligned {
- void *p;
- unsigned b2 __attribute__ ((mode (HI)));
- unsigned b4 __attribute__ ((mode (SI)));
- unsigned b8 __attribute__ ((mode (DI)));
-} __attribute__ ((packed));
-static inline void *
-read_pointer (void *p)
-{ union unaligned *up = p; return up->p; }
-static inline unsigned
-read_1byte (void *p)
-{ return *(unsigned char *)p; }
-static inline unsigned
-read_2byte (void *p)
-{ union unaligned *up = p; return up->b2; }
-static inline unsigned
-read_4byte (void *p)
-{ union unaligned *up = p; return up->b4; }
-static inline unsigned long
-read_8byte (void *p)
-{ union unaligned *up = p; return up->b8; }
-
-/* Ordering function for FDEs. Functions can't overlap, so we just compare
- their starting addresses. */
-
-static inline saddr
-fde_compare (fde *x, fde *y)
-{
- return (saddr)x->pc_begin - (saddr)y->pc_begin;
-}
-
-/* Return the address of the FDE after P. */
-
-static inline fde *
-next_fde (fde *p)
-{
- return (fde *)(((char *)p) + p->length + sizeof (p->length));
-}
-
-#include "frame.c"
-
-static size_t
-count_fdes (fde *this_fde)
-{
- size_t count;
-
- for (count = 0; this_fde->length != 0; this_fde = next_fde (this_fde))
- {
- /* Skip CIEs and linked once FDE entries. */
- if (this_fde->CIE_delta == 0 || this_fde->pc_begin == 0)
- continue;
-
- ++count;
- }
-
- return count;
-}
-
-static void
-add_fdes (fde *this_fde, fde_accumulator *accu, void **beg_ptr, void **end_ptr)
-{
- void *pc_begin = *beg_ptr;
- void *pc_end = *end_ptr;
-
- for (; this_fde->length != 0; this_fde = next_fde (this_fde))
- {
- /* Skip CIEs and linked once FDE entries. */
- if (this_fde->CIE_delta == 0 || this_fde->pc_begin == 0)
- continue;
-
- fde_insert (accu, this_fde);
-
- if (this_fde->pc_begin < pc_begin)
- pc_begin = this_fde->pc_begin;
- if (this_fde->pc_begin + this_fde->pc_range > pc_end)
- pc_end = this_fde->pc_begin + this_fde->pc_range;
- }
-
- *beg_ptr = pc_begin;
- *end_ptr = pc_end;
-}
-
-/* search this fde table for the one containing the pc */
-static fde *
-search_fdes (fde *this_fde, void *pc)
-{
- for (; this_fde->length != 0; this_fde = next_fde (this_fde))
- {
- /* Skip CIEs and linked once FDE entries. */
- if (this_fde->CIE_delta == 0 || this_fde->pc_begin == 0)
- continue;
-
- if ((uaddr)((char *)pc - (char *)this_fde->pc_begin) < this_fde->pc_range)
- return this_fde;
- }
- return NULL;
-}
-
-/* Set up a sorted array of pointers to FDEs for a loaded object. We
- count up the entries before allocating the array because it's likely to
- be faster. We can be called multiple times, should we have failed to
- allocate a sorted fde array on a previous occasion. */
-
-static void
-frame_init (struct object* ob)
-{
- size_t count;
- fde_accumulator accu;
- void *pc_begin, *pc_end;
- fde **array;
-
- if (ob->pc_begin)
- count = ob->count;
- else if (ob->fde_array)
- {
- fde **p = ob->fde_array;
- for (count = 0; *p; ++p)
- count += count_fdes (*p);
- }
- else
- count = count_fdes (ob->fde_begin);
- ob->count = count;
-
- if (!start_fde_sort (&accu, count) && ob->pc_begin)
- return;
-
- pc_begin = (void*)(uaddr)-1;
- pc_end = 0;
-
- if (ob->fde_array)
- {
- fde **p = ob->fde_array;
- for (; *p; ++p)
- add_fdes (*p, &accu, &pc_begin, &pc_end);
- }
- else
- add_fdes (ob->fde_begin, &accu, &pc_begin, &pc_end);
-
- array = end_fde_sort (&accu, count);
- if (array)
- ob->fde_array = array;
- ob->pc_begin = pc_begin;
- ob->pc_end = pc_end;
-}
-
-/* Return a pointer to the FDE for the function containing PC. */
-
-static fde *
-find_fde (void *pc)
-{
- struct object *ob;
- size_t lo, hi;
-
- init_object_mutex_once ();
- __gthread_mutex_lock (&object_mutex);
-
- /* Linear search through the objects, to find the one containing the pc. */
- for (ob = objects; ob; ob = ob->next)
- {
- if (ob->pc_begin == 0)
- frame_init (ob);
- if (pc >= ob->pc_begin && pc < ob->pc_end)
- break;
- }
-
- if (ob == 0)
- {
- __gthread_mutex_unlock (&object_mutex);
- return 0;
- }
-
- if (!ob->fde_array || (void *)ob->fde_array == (void *)ob->fde_begin)
- frame_init (ob);
-
- if (ob->fde_array && (void *)ob->fde_array != (void *)ob->fde_begin)
- {
- __gthread_mutex_unlock (&object_mutex);
-
- /* Standard binary search algorithm. */
- for (lo = 0, hi = ob->count; lo < hi; )
- {
- size_t i = (lo + hi) / 2;
- fde *f = ob->fde_array[i];
-
- if (pc < f->pc_begin)
- hi = i;
- else if (pc >= f->pc_begin + f->pc_range)
- lo = i + 1;
- else
- return f;
- }
- }
- else
- {
- /* Long slow labourious linear search, cos we've no memory. */
- fde *f;
-
- if (ob->fde_array)
- {
- fde **p = ob->fde_array;
-
- do
- {
- f = search_fdes (*p, pc);
- if (f)
- break;
- p++;
- }
- while (*p);
- }
- else
- f = search_fdes (ob->fde_begin, pc);
- __gthread_mutex_unlock (&object_mutex);
- return f;
- }
- return 0;
-}
-
-static inline struct dwarf_cie *
-get_cie (fde *f)
-{
- return ((void *)&f->CIE_delta) - f->CIE_delta;
-}
-
-/* Extract any interesting information from the CIE for the translation
- unit F belongs to. */
-
-static void *
-extract_cie_info (fde *f, struct cie_info *c)
-{
- void *p;
- int i;
-
- c->augmentation = get_cie (f)->augmentation;
-
- if (strcmp (c->augmentation, "") != 0
- && strcmp (c->augmentation, "eh") != 0
- && c->augmentation[0] != 'z')
- return 0;
-
- p = c->augmentation + strlen (c->augmentation) + 1;
-
- if (strcmp (c->augmentation, "eh") == 0)
- {
- c->eh_ptr = read_pointer (p);
- p += sizeof (void *);
- }
- else
- c->eh_ptr = 0;
-
- p = decode_uleb128 (p, &c->code_align);
- p = decode_sleb128 (p, &c->data_align);
- c->ra_regno = *(unsigned char *)p++;
-
- /* If the augmentation starts with 'z', we now see the length of the
- augmentation fields. */
- if (c->augmentation[0] == 'z')
- {
- p = decode_uleb128 (p, &i);
- p += i;
- }
-
- return p;
-}
-
-/* Decode a DW_OP stack operation. */
-
-static void *
-decode_stack_op (unsigned char *buf, struct frame_state *state)
-{
- enum dwarf_location_atom op;
- int offset;
-
- op = *buf++;
- switch (op)
- {
- case DW_OP_reg0:
- case DW_OP_reg1:
- case DW_OP_reg2:
- case DW_OP_reg3:
- case DW_OP_reg4:
- case DW_OP_reg5:
- case DW_OP_reg6:
- case DW_OP_reg7:
- case DW_OP_reg8:
- case DW_OP_reg9:
- case DW_OP_reg10:
- case DW_OP_reg11:
- case DW_OP_reg12:
- case DW_OP_reg13:
- case DW_OP_reg14:
- case DW_OP_reg15:
- case DW_OP_reg16:
- case DW_OP_reg17:
- case DW_OP_reg18:
- case DW_OP_reg19:
- case DW_OP_reg20:
- case DW_OP_reg21:
- case DW_OP_reg22:
- case DW_OP_reg23:
- case DW_OP_reg24:
- case DW_OP_reg25:
- case DW_OP_reg26:
- case DW_OP_reg27:
- case DW_OP_reg28:
- case DW_OP_reg29:
- case DW_OP_reg30:
- case DW_OP_reg31:
- state->cfa_reg = op - DW_OP_reg0;
- break;
- case DW_OP_regx:
- buf = decode_sleb128 (buf, &offset);
- state->cfa_reg = offset;
- break;
- case DW_OP_breg0:
- case DW_OP_breg1:
- case DW_OP_breg2:
- case DW_OP_breg3:
- case DW_OP_breg4:
- case DW_OP_breg5:
- case DW_OP_breg6:
- case DW_OP_breg7:
- case DW_OP_breg8:
- case DW_OP_breg9:
- case DW_OP_breg10:
- case DW_OP_breg11:
- case DW_OP_breg12:
- case DW_OP_breg13:
- case DW_OP_breg14:
- case DW_OP_breg15:
- case DW_OP_breg16:
- case DW_OP_breg17:
- case DW_OP_breg18:
- case DW_OP_breg19:
- case DW_OP_breg20:
- case DW_OP_breg21:
- case DW_OP_breg22:
- case DW_OP_breg23:
- case DW_OP_breg24:
- case DW_OP_breg25:
- case DW_OP_breg26:
- case DW_OP_breg27:
- case DW_OP_breg28:
- case DW_OP_breg29:
- case DW_OP_breg30:
- case DW_OP_breg31:
- state->cfa_reg = op - DW_OP_breg0;
- buf = decode_sleb128 (buf, &offset);
- state->base_offset = offset;
- break;
- case DW_OP_bregx:
- buf = decode_sleb128 (buf, &offset);
- state->cfa_reg = offset;
- buf = decode_sleb128 (buf, &offset);
- state->base_offset = offset;
- break;
- case DW_OP_deref:
- state->indirect = 1;
- break;
- case DW_OP_plus_uconst:
- buf = decode_uleb128 (buf, &offset);
- state->cfa_offset = offset;
- break;
- default:
- abort ();
- }
- return buf;
-}
-/* Decode one instruction's worth of DWARF 2 call frame information.
- Used by __frame_state_for. Takes pointers P to the instruction to
- decode, STATE to the current register unwind information, INFO to the
- current CIE information, and PC to the current PC value. Returns a
- pointer to the next instruction. */
-
-static void *
-execute_cfa_insn (void *p, struct frame_state_internal *state,
- struct cie_info *info, void **pc)
-{
- unsigned insn = *(unsigned char *)p++;
- unsigned reg;
- int offset;
-
- if (insn & DW_CFA_advance_loc)
- *pc += ((insn & 0x3f) * info->code_align);
- else if (insn & DW_CFA_offset)
- {
- reg = (insn & 0x3f);
- p = decode_uleb128 (p, &offset);
- if (reg == state->s.cfa_reg)
- /* Don't record anything about this register; it's only used to
- reload SP in the epilogue. We don't want to copy in SP
- values for outer frames; we handle restoring SP specially. */;
- else
- {
- offset *= info->data_align;
- state->s.saved[reg] = REG_SAVED_OFFSET;
- state->s.reg_or_offset[reg] = offset;
- }
- }
- else if (insn & DW_CFA_restore)
- {
- reg = (insn & 0x3f);
- state->s.saved[reg] = REG_UNSAVED;
- }
- else switch (insn)
- {
- case DW_CFA_set_loc:
- *pc = read_pointer (p);
- p += sizeof (void *);
- break;
- case DW_CFA_advance_loc1:
- *pc += read_1byte (p);
- p += 1;
- break;
- case DW_CFA_advance_loc2:
- *pc += read_2byte (p);
- p += 2;
- break;
- case DW_CFA_advance_loc4:
- *pc += read_4byte (p);
- p += 4;
- break;
-
- case DW_CFA_offset_extended:
- p = decode_uleb128 (p, &reg);
- p = decode_uleb128 (p, &offset);
- if (reg == state->s.cfa_reg)
- /* Don't record anything; see above. */;
- else
- {
- offset *= info->data_align;
- state->s.saved[reg] = REG_SAVED_OFFSET;
- state->s.reg_or_offset[reg] = offset;
- }
- break;
- case DW_CFA_restore_extended:
- p = decode_uleb128 (p, &reg);
- state->s.saved[reg] = REG_UNSAVED;
- break;
-
- case DW_CFA_undefined:
- case DW_CFA_same_value:
- case DW_CFA_nop:
- break;
-
- case DW_CFA_register:
- {
- unsigned reg2;
- p = decode_uleb128 (p, &reg);
- p = decode_uleb128 (p, &reg2);
- state->s.saved[reg] = REG_SAVED_REG;
- state->s.reg_or_offset[reg] = reg2;
- }
- break;
-
- case DW_CFA_def_cfa:
- p = decode_uleb128 (p, &reg);
- p = decode_uleb128 (p, &offset);
- state->s.cfa_reg = reg;
- state->s.cfa_offset = offset;
- break;
- case DW_CFA_def_cfa_register:
- p = decode_uleb128 (p, &reg);
- state->s.cfa_reg = reg;
- break;
- case DW_CFA_def_cfa_offset:
- p = decode_uleb128 (p, &offset);
- state->s.cfa_offset = offset;
- break;
- case DW_CFA_def_cfa_expression:
- {
- void *end;
- state->s.cfa_reg = 0;
- state->s.cfa_offset = 0;
- state->s.base_offset = 0;
- state->s.indirect = 0;
-
- p = decode_uleb128 (p, &offset);
- end = p + offset;
- while (p < end)
- p = decode_stack_op (p, &(state->s));
- break;
- }
-
- case DW_CFA_remember_state:
- {
- struct frame_state_internal *save =
- (struct frame_state_internal *)
- malloc (sizeof (struct frame_state_internal));
- memcpy (save, state, sizeof (struct frame_state_internal));
- state->saved_state = save;
- }
- break;
- case DW_CFA_restore_state:
- {
- struct frame_state_internal *save = state->saved_state;
- memcpy (state, save, sizeof (struct frame_state_internal));
- free (save);
- }
- break;
-
- /* FIXME: Hardcoded for SPARC register window configuration. */
- case DW_CFA_GNU_window_save:
- for (reg = 16; reg < 32; ++reg)
- {
- state->s.saved[reg] = REG_SAVED_OFFSET;
- state->s.reg_or_offset[reg] = (reg - 16) * sizeof (void *);
- }
- break;
-
- case DW_CFA_GNU_args_size:
- p = decode_uleb128 (p, &offset);
- state->s.args_size = offset;
- break;
-
- case DW_CFA_GNU_negative_offset_extended:
- p = decode_uleb128 (p, &reg);
- p = decode_uleb128 (p, &offset);
- offset *= info->data_align;
- state->s.saved[reg] = REG_SAVED_OFFSET;
- state->s.reg_or_offset[reg] = -offset;
- break;
-
- default:
- abort ();
- }
- return p;
-}
-
-/* Called from __throw to find the registers to restore for a given
- PC_TARGET. The caller should allocate a local variable of `struct
- frame_state' (declared in frame.h) and pass its address to STATE_IN. */
-
-struct frame_state *
-__frame_state_for (void *pc_target, struct frame_state *state_in)
-{
- fde *f;
- void *insn, *end, *pc;
- struct cie_info info;
- struct frame_state_internal state;
-
- f = find_fde (pc_target);
- if (f == 0)
- return 0;
-
- insn = extract_cie_info (f, &info);
- if (insn == 0)
- return 0;
-
- memset (&state, 0, sizeof (state));
- state.s.retaddr_column = info.ra_regno;
- state.s.eh_ptr = info.eh_ptr;
-
- /* First decode all the insns in the CIE. */
- end = next_fde ((fde*) get_cie (f));
- while (insn < end)
- insn = execute_cfa_insn (insn, &state, &info, 0);
-
- insn = ((fde *)f) + 1;
-
- if (info.augmentation[0] == 'z')
- {
- int i;
- insn = decode_uleb128 (insn, &i);
- insn += i;
- }
-
- /* Then the insns in the FDE up to our target PC. */
- end = next_fde (f);
- pc = f->pc_begin;
- while (insn < end && pc <= pc_target)
- insn = execute_cfa_insn (insn, &state, &info, &pc);
-
- memcpy (state_in, &state.s, sizeof (state.s));
- return state_in;
-}
-#endif /* DWARF2_UNWIND_INFO */
generated by cgit v1.2.3 (git 2.25.1) at 2024-06-09 03:37:33 +0000