diff options
Diffstat (limited to 'contrib/gcc/frame.c')
-rw-r--r-- | contrib/gcc/frame.c | 872 |
1 files changed, 0 insertions, 872 deletions
diff --git a/contrib/gcc/frame.c b/contrib/gcc/frame.c deleted file mode 100644 index 990a0ac..0000000 --- a/contrib/gcc/frame.c +++ /dev/null @@ -1,872 +0,0 @@ -/* Subroutines needed for unwinding stack frames for exception handling. */ -/* Compile this one with gcc. */ -/* Copyright (C) 1997, 1998, 2000 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. - -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. */ - -/* As a special exception, if you link this library with other files, - some of which are compiled with GCC, to produce an executable, - this library does not by itself cause the resulting executable - to be covered by the GNU General Public License. - This exception does not however invalidate any other reasons why - the executable file might be covered by the GNU General Public License. */ - -/* 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" - -/* We disable this when inhibit_libc, so that gcc can still be built without - needing header files first. */ -/* ??? This is not a good solution, since prototypes may be required in - some cases for correct code. See also libgcc2.c. */ -#ifndef inhibit_libc -/* fixproto guarantees these system headers exist. */ -#include <stdlib.h> -#include <unistd.h> -#endif - -#include "defaults.h" - -#ifdef DWARF2_UNWIND_INFO -#include "dwarf2.h" -#include <stddef.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)); -} - -/* Sorting an array of FDEs by address. - (Ideally we would have the linker sort the FDEs so we don't have to do - it at run time. But the linkers are not yet prepared for this.) */ - -/* This is a special mix of insertion sort and heap sort, optimized for - the data sets that actually occur. They look like - 101 102 103 127 128 105 108 110 190 111 115 119 125 160 126 129 130. - I.e. a linearly increasing sequence (coming from functions in the text - section), with additionally a few unordered elements (coming from functions - in gnu_linkonce sections) whose values are higher than the values in the - surrounding linear sequence (but not necessarily higher than the values - at the end of the linear sequence!). - The worst-case total run time is O(N) + O(n log (n)), where N is the - total number of FDEs and n is the number of erratic ones. */ - -typedef struct fde_vector -{ - fde **array; - size_t count; -} fde_vector; - -typedef struct fde_accumulator -{ - fde_vector linear; - fde_vector erratic; -} fde_accumulator; - -static inline void -start_fde_sort (fde_accumulator *accu, size_t count) -{ - accu->linear.array = (fde **) malloc (sizeof (fde *) * count); - accu->erratic.array = (fde **) malloc (sizeof (fde *) * count); - accu->linear.count = 0; - accu->erratic.count = 0; -} - -static inline void -fde_insert (fde_accumulator *accu, fde *this_fde) -{ - accu->linear.array[accu->linear.count++] = this_fde; -} - -/* Split LINEAR into a linear sequence with low values and an erratic - sequence with high values, put the linear one (of longest possible - length) into LINEAR and the erratic one into ERRATIC. This is O(N). */ -static inline void -fde_split (fde_vector *linear, fde_vector *erratic) -{ - size_t count = linear->count; - size_t linear_max = (size_t) -1; - size_t previous_max[count]; - size_t i, j; - - for (i = 0; i < count; i++) - { - for (j = linear_max; - j != (size_t) -1 - && fde_compare (linear->array[i], linear->array[j]) < 0; - j = previous_max[j]) - { - erratic->array[erratic->count++] = linear->array[j]; - linear->array[j] = (fde *) NULL; - } - previous_max[i] = j; - linear_max = i; - } - - for (i = 0, j = 0; i < count; i++) - if (linear->array[i] != (fde *) NULL) - linear->array[j++] = linear->array[i]; - linear->count = j; -} - -/* This is O(n log(n)). BSD/OS defines heapsort in stdlib.h, so we must - use a name that does not conflict. */ -static inline void -frame_heapsort (fde_vector *erratic) -{ - /* For a description of this algorithm, see: - Samuel P. Harbison, Guy L. Steele Jr.: C, a reference manual, 2nd ed., - p. 60-61. */ - fde ** a = erratic->array; - /* A portion of the array is called a "heap" if for all i>=0: - If i and 2i+1 are valid indices, then a[i] >= a[2i+1]. - If i and 2i+2 are valid indices, then a[i] >= a[2i+2]. */ -#define SWAP(x,y) do { fde * tmp = x; x = y; y = tmp; } while (0) - size_t n = erratic->count; - size_t m = n; - size_t i; - - while (m > 0) - { - /* Invariant: a[m..n-1] is a heap. */ - m--; - for (i = m; 2*i+1 < n; ) - { - if (2*i+2 < n - && fde_compare (a[2*i+2], a[2*i+1]) > 0 - && fde_compare (a[2*i+2], a[i]) > 0) - { - SWAP (a[i], a[2*i+2]); - i = 2*i+2; - } - else if (fde_compare (a[2*i+1], a[i]) > 0) - { - SWAP (a[i], a[2*i+1]); - i = 2*i+1; - } - else - break; - } - } - while (n > 1) - { - /* Invariant: a[0..n-1] is a heap. */ - n--; - SWAP (a[0], a[n]); - for (i = 0; 2*i+1 < n; ) - { - if (2*i+2 < n - && fde_compare (a[2*i+2], a[2*i+1]) > 0 - && fde_compare (a[2*i+2], a[i]) > 0) - { - SWAP (a[i], a[2*i+2]); - i = 2*i+2; - } - else if (fde_compare (a[2*i+1], a[i]) > 0) - { - SWAP (a[i], a[2*i+1]); - i = 2*i+1; - } - else - break; - } - } -#undef SWAP -} - -/* Merge V1 and V2, both sorted, and put the result into V1. */ -static void -fde_merge (fde_vector *v1, const fde_vector *v2) -{ - size_t i1, i2; - fde * fde2; - - i2 = v2->count; - if (i2 > 0) - { - i1 = v1->count; - do { - i2--; - fde2 = v2->array[i2]; - while (i1 > 0 && fde_compare (v1->array[i1-1], fde2) > 0) - { - v1->array[i1+i2] = v1->array[i1-1]; - i1--; - } - v1->array[i1+i2] = fde2; - } while (i2 > 0); - v1->count += v2->count; - } -} - -static fde ** -end_fde_sort (fde_accumulator *accu, size_t count) -{ - if (accu->linear.count != count) - abort (); - fde_split (&accu->linear, &accu->erratic); - if (accu->linear.count + accu->erratic.count != count) - abort (); - frame_heapsort (&accu->erratic); - fde_merge (&accu->linear, &accu->erratic); - free (accu->erratic.array); - return accu->linear.array; -} - -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; -} - -/* 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. */ - -static void -frame_init (struct object* ob) -{ - size_t count; - fde_accumulator accu; - void *pc_begin, *pc_end; - - 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; - - start_fde_sort (&accu, count); - 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); - - ob->fde_array = end_fde_sort (&accu, count); - 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); - - 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; - } - - __gthread_mutex_unlock (&object_mutex); - - if (ob == 0) - return 0; - - /* 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; - } - - 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 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); - 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, ®); - p = decode_uleb128 (p, &offset); - 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, ®); - 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, ®); - p = decode_uleb128 (p, ®2); - state->s.saved[reg] = REG_SAVED_REG; - state->s.reg_or_offset[reg] = reg2; - } - break; - - case DW_CFA_def_cfa: - p = decode_uleb128 (p, ®); - 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, ®); - 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_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, ®); - 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 crtbegin.o to register the unwind info for an object. */ - -void -__register_frame_info (void *begin, struct object *ob) -{ - ob->fde_begin = begin; - - ob->pc_begin = ob->pc_end = 0; - ob->fde_array = 0; - ob->count = 0; - - init_object_mutex_once (); - __gthread_mutex_lock (&object_mutex); - - ob->next = objects; - objects = ob; - - __gthread_mutex_unlock (&object_mutex); -} - -void -__register_frame (void *begin) -{ - struct object *ob = (struct object *) malloc (sizeof (struct object)); - __register_frame_info (begin, ob); -} - -/* Similar, but BEGIN is actually a pointer to a table of unwind entries - for different translation units. Called from the file generated by - collect2. */ - -void -__register_frame_info_table (void *begin, struct object *ob) -{ - ob->fde_begin = begin; - ob->fde_array = begin; - - ob->pc_begin = ob->pc_end = 0; - ob->count = 0; - - init_object_mutex_once (); - __gthread_mutex_lock (&object_mutex); - - ob->next = objects; - objects = ob; - - __gthread_mutex_unlock (&object_mutex); -} - -void -__register_frame_table (void *begin) -{ - struct object *ob = (struct object *) malloc (sizeof (struct object)); - __register_frame_info_table (begin, ob); -} - -/* Called from crtbegin.o to deregister the unwind info for an object. */ - -void * -__deregister_frame_info (void *begin) -{ - struct object **p; - - init_object_mutex_once (); - __gthread_mutex_lock (&object_mutex); - - p = &objects; - while (*p) - { - if ((*p)->fde_begin == begin) - { - struct object *ob = *p; - *p = (*p)->next; - - /* If we've run init_frame for this object, free the FDE array. */ - if (ob->pc_begin) - free (ob->fde_array); - - __gthread_mutex_unlock (&object_mutex); - return (void *) ob; - } - p = &((*p)->next); - } - - __gthread_mutex_unlock (&object_mutex); - abort (); -} - -void -__deregister_frame (void *begin) -{ - free (__deregister_frame_info (begin)); -} - -/* 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 */ |