/* dw2gencfi.c - Support for generating Dwarf2 CFI information. Copyright 2003, 2004, 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc. Contributed by Michal Ludvig This file is part of GAS, the GNU Assembler. GAS 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 3, or (at your option) any later version. GAS 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 GAS; see the file COPYING. If not, write to the Free Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA. */ #include "as.h" #include "dw2gencfi.h" #include "subsegs.h" #ifdef TARGET_USE_CFIPOP /* By default, use difference expressions if DIFF_EXPR_OK is defined. */ #ifndef CFI_DIFF_EXPR_OK # ifdef DIFF_EXPR_OK # define CFI_DIFF_EXPR_OK 1 # else # define CFI_DIFF_EXPR_OK 0 # endif #endif /* We re-use DWARF2_LINE_MIN_INSN_LENGTH for the code alignment field of the CIE. Default to 1 if not otherwise specified. */ #ifndef DWARF2_LINE_MIN_INSN_LENGTH # define DWARF2_LINE_MIN_INSN_LENGTH 1 #endif /* By default, use 32-bit relocations from .eh_frame into .text. */ #ifndef DWARF2_FDE_RELOC_SIZE # define DWARF2_FDE_RELOC_SIZE 4 #endif /* By default, use a read-only .eh_frame section. */ #ifndef DWARF2_EH_FRAME_READ_ONLY # define DWARF2_EH_FRAME_READ_ONLY SEC_READONLY #endif #ifndef EH_FRAME_ALIGNMENT # define EH_FRAME_ALIGNMENT (bfd_get_arch_size (stdoutput) == 64 ? 3 : 2) #endif #ifndef tc_cfi_frame_initial_instructions # define tc_cfi_frame_initial_instructions() ((void)0) #endif #ifndef DWARF2_ADDR_SIZE # define DWARF2_ADDR_SIZE(bfd) (bfd_arch_bits_per_address (bfd) / 8) #endif struct cfi_insn_data { struct cfi_insn_data *next; int insn; union { struct { unsigned reg; offsetT offset; } ri; struct { unsigned reg1; unsigned reg2; } rr; unsigned r; offsetT i; struct { symbolS *lab1; symbolS *lab2; } ll; struct cfi_escape_data { struct cfi_escape_data *next; expressionS exp; } *esc; struct { unsigned reg, encoding; expressionS exp; } ea; } u; }; struct fde_entry { struct fde_entry *next; symbolS *start_address; symbolS *end_address; struct cfi_insn_data *data; struct cfi_insn_data **last; unsigned char per_encoding; unsigned char lsda_encoding; expressionS personality; expressionS lsda; unsigned int return_column; unsigned int signal_frame; }; struct cie_entry { struct cie_entry *next; symbolS *start_address; unsigned int return_column; unsigned int signal_frame; unsigned char per_encoding; unsigned char lsda_encoding; expressionS personality; struct cfi_insn_data *first, *last; }; /* List of FDE entries. */ static struct fde_entry *all_fde_data; static struct fde_entry **last_fde_data = &all_fde_data; /* List of CIEs so that they could be reused. */ static struct cie_entry *cie_root; /* Stack of old CFI data, for save/restore. */ struct cfa_save_data { struct cfa_save_data *next; offsetT cfa_offset; }; /* Current open FDE entry. */ struct frch_cfi_data { struct fde_entry *cur_fde_data; symbolS *last_address; offsetT cur_cfa_offset; struct cfa_save_data *cfa_save_stack; }; /* Construct a new FDE structure and add it to the end of the fde list. */ static struct fde_entry * alloc_fde_entry (void) { struct fde_entry *fde = xcalloc (1, sizeof (struct fde_entry)); frchain_now->frch_cfi_data = xcalloc (1, sizeof (struct frch_cfi_data)); frchain_now->frch_cfi_data->cur_fde_data = fde; *last_fde_data = fde; last_fde_data = &fde->next; fde->last = &fde->data; fde->return_column = DWARF2_DEFAULT_RETURN_COLUMN; fde->per_encoding = DW_EH_PE_omit; fde->lsda_encoding = DW_EH_PE_omit; return fde; } /* The following functions are available for a backend to construct its own unwind information, usually from legacy unwind directives. */ /* Construct a new INSN structure and add it to the end of the insn list for the currently active FDE. */ static struct cfi_insn_data * alloc_cfi_insn_data (void) { struct cfi_insn_data *insn = xcalloc (1, sizeof (struct cfi_insn_data)); struct fde_entry *cur_fde_data = frchain_now->frch_cfi_data->cur_fde_data; *cur_fde_data->last = insn; cur_fde_data->last = &insn->next; return insn; } /* Construct a new FDE structure that begins at LABEL. */ void cfi_new_fde (symbolS *label) { struct fde_entry *fde = alloc_fde_entry (); fde->start_address = label; frchain_now->frch_cfi_data->last_address = label; } /* End the currently open FDE. */ void cfi_end_fde (symbolS *label) { frchain_now->frch_cfi_data->cur_fde_data->end_address = label; free (frchain_now->frch_cfi_data); frchain_now->frch_cfi_data = NULL; } /* Set the return column for the current FDE. */ void cfi_set_return_column (unsigned regno) { frchain_now->frch_cfi_data->cur_fde_data->return_column = regno; } /* Universal functions to store new instructions. */ static void cfi_add_CFA_insn(int insn) { struct cfi_insn_data *insn_ptr = alloc_cfi_insn_data (); insn_ptr->insn = insn; } static void cfi_add_CFA_insn_reg (int insn, unsigned regno) { struct cfi_insn_data *insn_ptr = alloc_cfi_insn_data (); insn_ptr->insn = insn; insn_ptr->u.r = regno; } static void cfi_add_CFA_insn_offset (int insn, offsetT offset) { struct cfi_insn_data *insn_ptr = alloc_cfi_insn_data (); insn_ptr->insn = insn; insn_ptr->u.i = offset; } static void cfi_add_CFA_insn_reg_reg (int insn, unsigned reg1, unsigned reg2) { struct cfi_insn_data *insn_ptr = alloc_cfi_insn_data (); insn_ptr->insn = insn; insn_ptr->u.rr.reg1 = reg1; insn_ptr->u.rr.reg2 = reg2; } static void cfi_add_CFA_insn_reg_offset (int insn, unsigned regno, offsetT offset) { struct cfi_insn_data *insn_ptr = alloc_cfi_insn_data (); insn_ptr->insn = insn; insn_ptr->u.ri.reg = regno; insn_ptr->u.ri.offset = offset; } /* Add a CFI insn to advance the PC from the last address to LABEL. */ void cfi_add_advance_loc (symbolS *label) { struct cfi_insn_data *insn = alloc_cfi_insn_data (); insn->insn = DW_CFA_advance_loc; insn->u.ll.lab1 = frchain_now->frch_cfi_data->last_address; insn->u.ll.lab2 = label; frchain_now->frch_cfi_data->last_address = label; } /* Add a DW_CFA_offset record to the CFI data. */ void cfi_add_CFA_offset (unsigned regno, offsetT offset) { unsigned int abs_data_align; assert (DWARF2_CIE_DATA_ALIGNMENT != 0); cfi_add_CFA_insn_reg_offset (DW_CFA_offset, regno, offset); abs_data_align = (DWARF2_CIE_DATA_ALIGNMENT < 0 ? -DWARF2_CIE_DATA_ALIGNMENT : DWARF2_CIE_DATA_ALIGNMENT); if (offset % abs_data_align) as_bad (_("register save offset not a multiple of %u"), abs_data_align); } /* Add a DW_CFA_def_cfa record to the CFI data. */ void cfi_add_CFA_def_cfa (unsigned regno, offsetT offset) { cfi_add_CFA_insn_reg_offset (DW_CFA_def_cfa, regno, offset); frchain_now->frch_cfi_data->cur_cfa_offset = offset; } /* Add a DW_CFA_register record to the CFI data. */ void cfi_add_CFA_register (unsigned reg1, unsigned reg2) { cfi_add_CFA_insn_reg_reg (DW_CFA_register, reg1, reg2); } /* Add a DW_CFA_def_cfa_register record to the CFI data. */ void cfi_add_CFA_def_cfa_register (unsigned regno) { cfi_add_CFA_insn_reg (DW_CFA_def_cfa_register, regno); } /* Add a DW_CFA_def_cfa_offset record to the CFI data. */ void cfi_add_CFA_def_cfa_offset (offsetT offset) { cfi_add_CFA_insn_offset (DW_CFA_def_cfa_offset, offset); frchain_now->frch_cfi_data->cur_cfa_offset = offset; } void cfi_add_CFA_restore (unsigned regno) { cfi_add_CFA_insn_reg (DW_CFA_restore, regno); } void cfi_add_CFA_undefined (unsigned regno) { cfi_add_CFA_insn_reg (DW_CFA_undefined, regno); } void cfi_add_CFA_same_value (unsigned regno) { cfi_add_CFA_insn_reg (DW_CFA_same_value, regno); } void cfi_add_CFA_remember_state (void) { struct cfa_save_data *p; cfi_add_CFA_insn (DW_CFA_remember_state); p = xmalloc (sizeof (*p)); p->cfa_offset = frchain_now->frch_cfi_data->cur_cfa_offset; p->next = frchain_now->frch_cfi_data->cfa_save_stack; frchain_now->frch_cfi_data->cfa_save_stack = p; } void cfi_add_CFA_restore_state (void) { struct cfa_save_data *p; cfi_add_CFA_insn (DW_CFA_restore_state); p = frchain_now->frch_cfi_data->cfa_save_stack; if (p) { frchain_now->frch_cfi_data->cur_cfa_offset = p->cfa_offset; frchain_now->frch_cfi_data->cfa_save_stack = p->next; free (p); } else as_bad (_("CFI state restore without previous remember")); } /* Parse CFI assembler directives. */ static void dot_cfi (int); static void dot_cfi_escape (int); static void dot_cfi_startproc (int); static void dot_cfi_endproc (int); static void dot_cfi_personality (int); static void dot_cfi_lsda (int); static void dot_cfi_val_encoded_addr (int); /* Fake CFI type; outside the byte range of any real CFI insn. */ #define CFI_adjust_cfa_offset 0x100 #define CFI_return_column 0x101 #define CFI_rel_offset 0x102 #define CFI_escape 0x103 #define CFI_signal_frame 0x104 #define CFI_val_encoded_addr 0x105 const pseudo_typeS cfi_pseudo_table[] = { { "cfi_startproc", dot_cfi_startproc, 0 }, { "cfi_endproc", dot_cfi_endproc, 0 }, { "cfi_def_cfa", dot_cfi, DW_CFA_def_cfa }, { "cfi_def_cfa_register", dot_cfi, DW_CFA_def_cfa_register }, { "cfi_def_cfa_offset", dot_cfi, DW_CFA_def_cfa_offset }, { "cfi_adjust_cfa_offset", dot_cfi, CFI_adjust_cfa_offset }, { "cfi_offset", dot_cfi, DW_CFA_offset }, { "cfi_rel_offset", dot_cfi, CFI_rel_offset }, { "cfi_register", dot_cfi, DW_CFA_register }, { "cfi_return_column", dot_cfi, CFI_return_column }, { "cfi_restore", dot_cfi, DW_CFA_restore }, { "cfi_undefined", dot_cfi, DW_CFA_undefined }, { "cfi_same_value", dot_cfi, DW_CFA_same_value }, { "cfi_remember_state", dot_cfi, DW_CFA_remember_state }, { "cfi_restore_state", dot_cfi, DW_CFA_restore_state }, { "cfi_window_save", dot_cfi, DW_CFA_GNU_window_save }, { "cfi_escape", dot_cfi_escape, 0 }, { "cfi_signal_frame", dot_cfi, CFI_signal_frame }, { "cfi_personality", dot_cfi_personality, 0 }, { "cfi_lsda", dot_cfi_lsda, 0 }, { "cfi_val_encoded_addr", dot_cfi_val_encoded_addr, 0 }, { NULL, NULL, 0 } }; static void cfi_parse_separator (void) { SKIP_WHITESPACE (); if (*input_line_pointer == ',') input_line_pointer++; else as_bad (_("missing separator")); } #ifndef tc_parse_to_dw2regnum static void tc_parse_to_dw2regnum(expressionS *exp) { # ifdef tc_regname_to_dw2regnum SKIP_WHITESPACE (); if (is_name_beginner (*input_line_pointer) || (*input_line_pointer == '%' && is_name_beginner (*++input_line_pointer))) { char *name, c; name = input_line_pointer; c = get_symbol_end (); exp->X_op = O_constant; exp->X_add_number = tc_regname_to_dw2regnum (name); *input_line_pointer = c; } else # endif expression_and_evaluate (exp); } #endif static unsigned cfi_parse_reg (void) { int regno; expressionS exp; tc_parse_to_dw2regnum (&exp); switch (exp.X_op) { case O_register: case O_constant: regno = exp.X_add_number; break; default: regno = -1; break; } if (regno < 0) { as_bad (_("bad register expression")); regno = 0; } return regno; } static offsetT cfi_parse_const (void) { return get_absolute_expression (); } static void dot_cfi (int arg) { offsetT offset; unsigned reg1, reg2; if (frchain_now->frch_cfi_data == NULL) { as_bad (_("CFI instruction used without previous .cfi_startproc")); ignore_rest_of_line (); return; } /* If the last address was not at the current PC, advance to current. */ if (symbol_get_frag (frchain_now->frch_cfi_data->last_address) != frag_now || S_GET_VALUE (frchain_now->frch_cfi_data->last_address) != frag_now_fix ()) cfi_add_advance_loc (symbol_temp_new_now ()); switch (arg) { case DW_CFA_offset: reg1 = cfi_parse_reg (); cfi_parse_separator (); offset = cfi_parse_const (); cfi_add_CFA_offset (reg1, offset); break; case CFI_rel_offset: reg1 = cfi_parse_reg (); cfi_parse_separator (); offset = cfi_parse_const (); cfi_add_CFA_offset (reg1, offset - frchain_now->frch_cfi_data->cur_cfa_offset); break; case DW_CFA_def_cfa: reg1 = cfi_parse_reg (); cfi_parse_separator (); offset = cfi_parse_const (); cfi_add_CFA_def_cfa (reg1, offset); break; case DW_CFA_register: reg1 = cfi_parse_reg (); cfi_parse_separator (); reg2 = cfi_parse_reg (); cfi_add_CFA_register (reg1, reg2); break; case DW_CFA_def_cfa_register: reg1 = cfi_parse_reg (); cfi_add_CFA_def_cfa_register (reg1); break; case DW_CFA_def_cfa_offset: offset = cfi_parse_const (); cfi_add_CFA_def_cfa_offset (offset); break; case CFI_adjust_cfa_offset: offset = cfi_parse_const (); cfi_add_CFA_def_cfa_offset (frchain_now->frch_cfi_data->cur_cfa_offset + offset); break; case DW_CFA_restore: for (;;) { reg1 = cfi_parse_reg (); cfi_add_CFA_restore (reg1); SKIP_WHITESPACE (); if (*input_line_pointer != ',') break; ++input_line_pointer; } break; case DW_CFA_undefined: for (;;) { reg1 = cfi_parse_reg (); cfi_add_CFA_undefined (reg1); SKIP_WHITESPACE (); if (*input_line_pointer != ',') break; ++input_line_pointer; } break; case DW_CFA_same_value: reg1 = cfi_parse_reg (); cfi_add_CFA_same_value (reg1); break; case CFI_return_column: reg1 = cfi_parse_reg (); cfi_set_return_column (reg1); break; case DW_CFA_remember_state: cfi_add_CFA_remember_state (); break; case DW_CFA_restore_state: cfi_add_CFA_restore_state (); break; case DW_CFA_GNU_window_save: cfi_add_CFA_insn (DW_CFA_GNU_window_save); break; case CFI_signal_frame: frchain_now->frch_cfi_data->cur_fde_data->signal_frame = 1; break; default: abort (); } demand_empty_rest_of_line (); } static void dot_cfi_escape (int ignored ATTRIBUTE_UNUSED) { struct cfi_escape_data *head, **tail, *e; struct cfi_insn_data *insn; if (frchain_now->frch_cfi_data == NULL) { as_bad (_("CFI instruction used without previous .cfi_startproc")); ignore_rest_of_line (); return; } /* If the last address was not at the current PC, advance to current. */ if (symbol_get_frag (frchain_now->frch_cfi_data->last_address) != frag_now || S_GET_VALUE (frchain_now->frch_cfi_data->last_address) != frag_now_fix ()) cfi_add_advance_loc (symbol_temp_new_now ()); tail = &head; do { e = xmalloc (sizeof (*e)); do_parse_cons_expression (&e->exp, 1); *tail = e; tail = &e->next; } while (*input_line_pointer++ == ','); *tail = NULL; insn = alloc_cfi_insn_data (); insn->insn = CFI_escape; insn->u.esc = head; --input_line_pointer; demand_empty_rest_of_line (); } static void dot_cfi_personality (int ignored ATTRIBUTE_UNUSED) { struct fde_entry *fde; offsetT encoding; if (frchain_now->frch_cfi_data == NULL) { as_bad (_("CFI instruction used without previous .cfi_startproc")); ignore_rest_of_line (); return; } fde = frchain_now->frch_cfi_data->cur_fde_data; encoding = cfi_parse_const (); if (encoding == DW_EH_PE_omit) { demand_empty_rest_of_line (); fde->per_encoding = encoding; return; } if ((encoding & 0xff) != encoding || ((encoding & 0x70) != 0 #if CFI_DIFF_EXPR_OK || defined tc_cfi_emit_pcrel_expr && (encoding & 0x70) != DW_EH_PE_pcrel #endif ) /* leb128 can be handled, but does something actually need it? */ || (encoding & 7) == DW_EH_PE_uleb128 || (encoding & 7) > DW_EH_PE_udata8) { as_bad (_("invalid or unsupported encoding in .cfi_personality")); ignore_rest_of_line (); return; } if (*input_line_pointer++ != ',') { as_bad (_(".cfi_personality requires encoding and symbol arguments")); ignore_rest_of_line (); return; } expression_and_evaluate (&fde->personality); switch (fde->personality.X_op) { case O_symbol: break; case O_constant: if ((encoding & 0x70) == DW_EH_PE_pcrel) encoding = DW_EH_PE_omit; break; default: encoding = DW_EH_PE_omit; break; } fde->per_encoding = encoding; if (encoding == DW_EH_PE_omit) { as_bad (_("wrong second argument to .cfi_personality")); ignore_rest_of_line (); return; } demand_empty_rest_of_line (); } static void dot_cfi_lsda (int ignored ATTRIBUTE_UNUSED) { struct fde_entry *fde; offsetT encoding; if (frchain_now->frch_cfi_data == NULL) { as_bad (_("CFI instruction used without previous .cfi_startproc")); ignore_rest_of_line (); return; } fde = frchain_now->frch_cfi_data->cur_fde_data; encoding = cfi_parse_const (); if (encoding == DW_EH_PE_omit) { demand_empty_rest_of_line (); fde->lsda_encoding = encoding; return; } if ((encoding & 0xff) != encoding || ((encoding & 0x70) != 0 #if CFI_DIFF_EXPR_OK || defined tc_cfi_emit_pcrel_expr && (encoding & 0x70) != DW_EH_PE_pcrel #endif ) /* leb128 can be handled, but does something actually need it? */ || (encoding & 7) == DW_EH_PE_uleb128 || (encoding & 7) > DW_EH_PE_udata8) { as_bad (_("invalid or unsupported encoding in .cfi_lsda")); ignore_rest_of_line (); return; } if (*input_line_pointer++ != ',') { as_bad (_(".cfi_lsda requires encoding and symbol arguments")); ignore_rest_of_line (); return; } fde->lsda_encoding = encoding; expression_and_evaluate (&fde->lsda); switch (fde->lsda.X_op) { case O_symbol: break; case O_constant: if ((encoding & 0x70) == DW_EH_PE_pcrel) encoding = DW_EH_PE_omit; break; default: encoding = DW_EH_PE_omit; break; } fde->lsda_encoding = encoding; if (encoding == DW_EH_PE_omit) { as_bad (_("wrong second argument to .cfi_lsda")); ignore_rest_of_line (); return; } demand_empty_rest_of_line (); } static void dot_cfi_val_encoded_addr (int ignored ATTRIBUTE_UNUSED) { struct cfi_insn_data *insn_ptr; offsetT encoding; if (frchain_now->frch_cfi_data == NULL) { as_bad (_("CFI instruction used without previous .cfi_startproc")); ignore_rest_of_line (); return; } /* If the last address was not at the current PC, advance to current. */ if (symbol_get_frag (frchain_now->frch_cfi_data->last_address) != frag_now || S_GET_VALUE (frchain_now->frch_cfi_data->last_address) != frag_now_fix ()) cfi_add_advance_loc (symbol_temp_new_now ()); insn_ptr = alloc_cfi_insn_data (); insn_ptr->insn = CFI_val_encoded_addr; insn_ptr->u.ea.reg = cfi_parse_reg (); cfi_parse_separator (); encoding = cfi_parse_const (); if ((encoding & 0xff) != encoding || ((encoding & 0x70) != 0 #if CFI_DIFF_EXPR_OK || defined tc_cfi_emit_pcrel_expr && (encoding & 0x70) != DW_EH_PE_pcrel #endif ) /* leb128 can be handled, but does something actually need it? */ || (encoding & 7) == DW_EH_PE_uleb128 || (encoding & 7) > DW_EH_PE_udata8) { as_bad (_("invalid or unsupported encoding in .cfi_lsda")); encoding = DW_EH_PE_omit; } cfi_parse_separator (); expression_and_evaluate (&insn_ptr->u.ea.exp); switch (insn_ptr->u.ea.exp.X_op) { case O_symbol: break; case O_constant: if ((encoding & 0x70) != DW_EH_PE_pcrel) break; default: encoding = DW_EH_PE_omit; break; } insn_ptr->u.ea.encoding = encoding; if (encoding == DW_EH_PE_omit) { as_bad (_("wrong third argument to .cfi_val_encoded_addr")); ignore_rest_of_line (); return; } demand_empty_rest_of_line (); } static void dot_cfi_startproc (int ignored ATTRIBUTE_UNUSED) { int simple = 0; if (frchain_now->frch_cfi_data != NULL) { as_bad (_("previous CFI entry not closed (missing .cfi_endproc)")); ignore_rest_of_line (); return; } cfi_new_fde (symbol_temp_new_now ()); SKIP_WHITESPACE (); if (is_name_beginner (*input_line_pointer)) { char *name, c; name = input_line_pointer; c = get_symbol_end (); if (strcmp (name, "simple") == 0) { simple = 1; *input_line_pointer = c; } else input_line_pointer = name; } demand_empty_rest_of_line (); frchain_now->frch_cfi_data->cur_cfa_offset = 0; if (!simple) tc_cfi_frame_initial_instructions (); } static void dot_cfi_endproc (int ignored ATTRIBUTE_UNUSED) { if (frchain_now->frch_cfi_data == NULL) { as_bad (_(".cfi_endproc without corresponding .cfi_startproc")); ignore_rest_of_line (); return; } cfi_end_fde (symbol_temp_new_now ()); demand_empty_rest_of_line (); } /* Emit a single byte into the current segment. */ static inline void out_one (int byte) { FRAG_APPEND_1_CHAR (byte); } /* Emit a two-byte word into the current segment. */ static inline void out_two (int data) { md_number_to_chars (frag_more (2), data, 2); } /* Emit a four byte word into the current segment. */ static inline void out_four (int data) { md_number_to_chars (frag_more (4), data, 4); } /* Emit an unsigned "little-endian base 128" number. */ static void out_uleb128 (addressT value) { output_leb128 (frag_more (sizeof_leb128 (value, 0)), value, 0); } /* Emit an unsigned "little-endian base 128" number. */ static void out_sleb128 (offsetT value) { output_leb128 (frag_more (sizeof_leb128 (value, 1)), value, 1); } static void output_cfi_insn (struct cfi_insn_data *insn) { offsetT offset; unsigned int regno; switch (insn->insn) { case DW_CFA_advance_loc: { symbolS *from = insn->u.ll.lab1; symbolS *to = insn->u.ll.lab2; if (symbol_get_frag (to) == symbol_get_frag (from)) { addressT delta = S_GET_VALUE (to) - S_GET_VALUE (from); addressT scaled = delta / DWARF2_LINE_MIN_INSN_LENGTH; if (scaled <= 0x3F) out_one (DW_CFA_advance_loc + scaled); else if (scaled <= 0xFF) { out_one (DW_CFA_advance_loc1); out_one (scaled); } else if (scaled <= 0xFFFF) { out_one (DW_CFA_advance_loc2); out_two (scaled); } else { out_one (DW_CFA_advance_loc4); out_four (scaled); } } else { expressionS exp; exp.X_op = O_subtract; exp.X_add_symbol = to; exp.X_op_symbol = from; exp.X_add_number = 0; /* The code in ehopt.c expects that one byte of the encoding is already allocated to the frag. This comes from the way that it scans the .eh_frame section looking first for the .byte DW_CFA_advance_loc4. */ *frag_more (1) = DW_CFA_advance_loc4; frag_var (rs_cfa, 4, 0, DWARF2_LINE_MIN_INSN_LENGTH << 3, make_expr_symbol (&exp), frag_now_fix () - 1, (char *) frag_now); } } break; case DW_CFA_def_cfa: offset = insn->u.ri.offset; if (offset < 0) { out_one (DW_CFA_def_cfa_sf); out_uleb128 (insn->u.ri.reg); out_sleb128 (offset / DWARF2_CIE_DATA_ALIGNMENT); } else { out_one (DW_CFA_def_cfa); out_uleb128 (insn->u.ri.reg); out_uleb128 (offset); } break; case DW_CFA_def_cfa_register: case DW_CFA_undefined: case DW_CFA_same_value: out_one (insn->insn); out_uleb128 (insn->u.r); break; case DW_CFA_def_cfa_offset: offset = insn->u.i; if (offset < 0) { out_one (DW_CFA_def_cfa_offset_sf); out_sleb128 (offset / DWARF2_CIE_DATA_ALIGNMENT); } else { out_one (DW_CFA_def_cfa_offset); out_uleb128 (offset); } break; case DW_CFA_restore: regno = insn->u.r; if (regno <= 0x3F) { out_one (DW_CFA_restore + regno); } else { out_one (DW_CFA_restore_extended); out_uleb128 (regno); } break; case DW_CFA_offset: regno = insn->u.ri.reg; offset = insn->u.ri.offset / DWARF2_CIE_DATA_ALIGNMENT; if (offset < 0) { out_one (DW_CFA_offset_extended_sf); out_uleb128 (regno); out_sleb128 (offset); } else if (regno <= 0x3F) { out_one (DW_CFA_offset + regno); out_uleb128 (offset); } else { out_one (DW_CFA_offset_extended); out_uleb128 (regno); out_uleb128 (offset); } break; case DW_CFA_register: out_one (DW_CFA_register); out_uleb128 (insn->u.rr.reg1); out_uleb128 (insn->u.rr.reg2); break; case DW_CFA_remember_state: case DW_CFA_restore_state: out_one (insn->insn); break; case DW_CFA_GNU_window_save: out_one (DW_CFA_GNU_window_save); break; case CFI_escape: { struct cfi_escape_data *e; for (e = insn->u.esc; e ; e = e->next) emit_expr (&e->exp, 1); break; } case CFI_val_encoded_addr: { unsigned encoding = insn->u.ea.encoding; offsetT encoding_size; if (encoding == DW_EH_PE_omit) break; out_one (DW_CFA_val_expression); out_uleb128 (insn->u.ea.reg); switch (encoding & 0x7) { case DW_EH_PE_absptr: encoding_size = DWARF2_ADDR_SIZE (stdoutput); break; case DW_EH_PE_udata2: encoding_size = 2; break; case DW_EH_PE_udata4: encoding_size = 4; break; case DW_EH_PE_udata8: encoding_size = 8; break; default: abort (); } /* If the user has requested absolute encoding, then use the smaller DW_OP_addr encoding. */ if (insn->u.ea.encoding == DW_EH_PE_absptr) { out_uleb128 (1 + encoding_size); out_one (DW_OP_addr); } else { out_uleb128 (1 + 1 + encoding_size); out_one (DW_OP_GNU_encoded_addr); out_one (encoding); if ((encoding & 0x70) == DW_EH_PE_pcrel) { #if CFI_DIFF_EXPR_OK insn->u.ea.exp.X_op = O_subtract; insn->u.ea.exp.X_op_symbol = symbol_temp_new_now (); #elif defined (tc_cfi_emit_pcrel_expr) tc_cfi_emit_pcrel_expr (&insn->u.ea.exp, encoding_size); break; #else abort (); #endif } } emit_expr (&insn->u.ea.exp, encoding_size); } break; default: abort (); } } static offsetT encoding_size (unsigned char encoding) { if (encoding == DW_EH_PE_omit) return 0; switch (encoding & 0x7) { case 0: return bfd_get_arch_size (stdoutput) == 64 ? 8 : 4; case DW_EH_PE_udata2: return 2; case DW_EH_PE_udata4: return 4; case DW_EH_PE_udata8: return 8; default: abort (); } } static void output_cie (struct cie_entry *cie) { symbolS *after_size_address, *end_address; expressionS exp; struct cfi_insn_data *i; offsetT augmentation_size; int enc; cie->start_address = symbol_temp_new_now (); after_size_address = symbol_temp_make (); end_address = symbol_temp_make (); exp.X_op = O_subtract; exp.X_add_symbol = end_address; exp.X_op_symbol = after_size_address; exp.X_add_number = 0; emit_expr (&exp, 4); /* Length. */ symbol_set_value_now (after_size_address); out_four (0); /* CIE id. */ out_one (DW_CIE_VERSION); /* Version. */ out_one ('z'); /* Augmentation. */ if (cie->per_encoding != DW_EH_PE_omit) out_one ('P'); if (cie->lsda_encoding != DW_EH_PE_omit) out_one ('L'); out_one ('R'); if (cie->signal_frame) out_one ('S'); out_one (0); out_uleb128 (DWARF2_LINE_MIN_INSN_LENGTH); /* Code alignment. */ out_sleb128 (DWARF2_CIE_DATA_ALIGNMENT); /* Data alignment. */ if (DW_CIE_VERSION == 1) /* Return column. */ out_one (cie->return_column); else out_uleb128 (cie->return_column); augmentation_size = 1 + (cie->lsda_encoding != DW_EH_PE_omit); if (cie->per_encoding != DW_EH_PE_omit) augmentation_size += 1 + encoding_size (cie->per_encoding); out_uleb128 (augmentation_size); /* Augmentation size. */ if (cie->per_encoding != DW_EH_PE_omit) { offsetT size = encoding_size (cie->per_encoding); out_one (cie->per_encoding); exp = cie->personality; if ((cie->per_encoding & 0x70) == DW_EH_PE_pcrel) { #if CFI_DIFF_EXPR_OK exp.X_op = O_subtract; exp.X_op_symbol = symbol_temp_new_now (); emit_expr (&exp, size); #elif defined (tc_cfi_emit_pcrel_expr) tc_cfi_emit_pcrel_expr (&exp, size); #else abort (); #endif } else emit_expr (&exp, size); } if (cie->lsda_encoding != DW_EH_PE_omit) out_one (cie->lsda_encoding); switch (DWARF2_FDE_RELOC_SIZE) { case 2: enc = DW_EH_PE_sdata2; break; case 4: enc = DW_EH_PE_sdata4; break; case 8: enc = DW_EH_PE_sdata8; break; default: abort (); } #if CFI_DIFF_EXPR_OK || defined tc_cfi_emit_pcrel_expr enc |= DW_EH_PE_pcrel; #endif out_one (enc); if (cie->first) for (i = cie->first; i != cie->last; i = i->next) output_cfi_insn (i); frag_align (2, DW_CFA_nop, 0); symbol_set_value_now (end_address); } static void output_fde (struct fde_entry *fde, struct cie_entry *cie, struct cfi_insn_data *first, int align) { symbolS *after_size_address, *end_address; expressionS exp; offsetT augmentation_size; after_size_address = symbol_temp_make (); end_address = symbol_temp_make (); exp.X_op = O_subtract; exp.X_add_symbol = end_address; exp.X_op_symbol = after_size_address; exp.X_add_number = 0; emit_expr (&exp, 4); /* Length. */ symbol_set_value_now (after_size_address); exp.X_add_symbol = after_size_address; exp.X_op_symbol = cie->start_address; emit_expr (&exp, 4); /* CIE offset. */ #if CFI_DIFF_EXPR_OK exp.X_add_symbol = fde->start_address; exp.X_op_symbol = symbol_temp_new_now (); emit_expr (&exp, DWARF2_FDE_RELOC_SIZE); /* Code offset. */ #else exp.X_op = O_symbol; exp.X_add_symbol = fde->start_address; exp.X_op_symbol = NULL; #ifdef tc_cfi_emit_pcrel_expr tc_cfi_emit_pcrel_expr (&exp, DWARF2_FDE_RELOC_SIZE); /* Code offset. */ #else emit_expr (&exp, DWARF2_FDE_RELOC_SIZE); /* Code offset. */ #endif exp.X_op = O_subtract; #endif exp.X_add_symbol = fde->end_address; exp.X_op_symbol = fde->start_address; /* Code length. */ emit_expr (&exp, DWARF2_FDE_RELOC_SIZE); augmentation_size = encoding_size (fde->lsda_encoding); out_uleb128 (augmentation_size); /* Augmentation size. */ if (fde->lsda_encoding != DW_EH_PE_omit) { exp = fde->lsda; if ((fde->lsda_encoding & 0x70) == DW_EH_PE_pcrel) { #if CFI_DIFF_EXPR_OK exp.X_op = O_subtract; exp.X_op_symbol = symbol_temp_new_now (); emit_expr (&exp, augmentation_size); #elif defined (tc_cfi_emit_pcrel_expr) tc_cfi_emit_pcrel_expr (&exp, augmentation_size); #else abort (); #endif } else emit_expr (&exp, augmentation_size); } for (; first; first = first->next) output_cfi_insn (first); frag_align (align, DW_CFA_nop, 0); symbol_set_value_now (end_address); } static struct cie_entry * select_cie_for_fde (struct fde_entry *fde, struct cfi_insn_data **pfirst) { struct cfi_insn_data *i, *j; struct cie_entry *cie; for (cie = cie_root; cie; cie = cie->next) { if (cie->return_column != fde->return_column || cie->signal_frame != fde->signal_frame || cie->per_encoding != fde->per_encoding || cie->lsda_encoding != fde->lsda_encoding) continue; if (cie->per_encoding != DW_EH_PE_omit) { if (cie->personality.X_op != fde->personality.X_op || cie->personality.X_add_number != fde->personality.X_add_number) continue; switch (cie->personality.X_op) { case O_constant: if (cie->personality.X_unsigned != fde->personality.X_unsigned) continue; break; case O_symbol: if (cie->personality.X_add_symbol != fde->personality.X_add_symbol) continue; break; default: abort (); } } for (i = cie->first, j = fde->data; i != cie->last && j != NULL; i = i->next, j = j->next) { if (i->insn != j->insn) goto fail; switch (i->insn) { case DW_CFA_advance_loc: case DW_CFA_remember_state: /* We reached the first advance/remember in the FDE, but did not reach the end of the CIE list. */ goto fail; case DW_CFA_offset: case DW_CFA_def_cfa: if (i->u.ri.reg != j->u.ri.reg) goto fail; if (i->u.ri.offset != j->u.ri.offset) goto fail; break; case DW_CFA_register: if (i->u.rr.reg1 != j->u.rr.reg1) goto fail; if (i->u.rr.reg2 != j->u.rr.reg2) goto fail; break; case DW_CFA_def_cfa_register: case DW_CFA_restore: case DW_CFA_undefined: case DW_CFA_same_value: if (i->u.r != j->u.r) goto fail; break; case DW_CFA_def_cfa_offset: if (i->u.i != j->u.i) goto fail; break; case CFI_escape: case CFI_val_encoded_addr: /* Don't bother matching these for now. */ goto fail; default: abort (); } } /* Success if we reached the end of the CIE list, and we've either run out of FDE entries or we've encountered an advance, remember, or escape. */ if (i == cie->last && (!j || j->insn == DW_CFA_advance_loc || j->insn == DW_CFA_remember_state || j->insn == CFI_escape || j->insn == CFI_val_encoded_addr)) { *pfirst = j; return cie; } fail:; } cie = xmalloc (sizeof (struct cie_entry)); cie->next = cie_root; cie_root = cie; cie->return_column = fde->return_column; cie->signal_frame = fde->signal_frame; cie->per_encoding = fde->per_encoding; cie->lsda_encoding = fde->lsda_encoding; cie->personality = fde->personality; cie->first = fde->data; for (i = cie->first; i ; i = i->next) if (i->insn == DW_CFA_advance_loc || i->insn == DW_CFA_remember_state || i->insn == CFI_escape || i->insn == CFI_val_encoded_addr) break; cie->last = i; *pfirst = i; output_cie (cie); return cie; } void cfi_finish (void) { segT cfi_seg; struct fde_entry *fde; int save_flag_traditional_format; if (all_fde_data == 0) return; /* Open .eh_frame section. */ cfi_seg = subseg_new (".eh_frame", 0); bfd_set_section_flags (stdoutput, cfi_seg, SEC_ALLOC | SEC_LOAD | SEC_DATA | DWARF2_EH_FRAME_READ_ONLY); subseg_set (cfi_seg, 0); record_alignment (cfi_seg, EH_FRAME_ALIGNMENT); #ifdef md_fix_up_eh_frame md_fix_up_eh_frame (cfi_seg); #endif /* Make sure check_eh_frame doesn't do anything with our output. */ save_flag_traditional_format = flag_traditional_format; flag_traditional_format = 1; for (fde = all_fde_data; fde ; fde = fde->next) { struct cfi_insn_data *first; struct cie_entry *cie; if (fde->end_address == NULL) { as_bad (_("open CFI at the end of file; missing .cfi_endproc directive")); fde->end_address = fde->start_address; } cie = select_cie_for_fde (fde, &first); output_fde (fde, cie, first, fde->next == NULL ? EH_FRAME_ALIGNMENT : 2); } flag_traditional_format = save_flag_traditional_format; } #else /* TARGET_USE_CFIPOP */ void cfi_finish (void) { } #endif /* TARGET_USE_CFIPOP */