cfgexpand.c (struct stack_vars_data): Add asan_base and asan_alignb fields.
* cfgexpand.c (struct stack_vars_data): Add asan_base and asan_alignb fields. (expand_stack_vars): For -fsanitize=address, use (and set initially) data->asan_base as base for vars and update asan_alignb. (expand_used_vars): Initialize data.asan_base and data.asan_alignb. Pass them to asan_emit_stack_protection. * asan.c (asan_detect_stack_use_after_return): New variable. (asan_emit_stack_protection): Add pbase and alignb arguments. Implement use after return sanitization. * asan.h (asan_emit_stack_protection): Adjust prototype. (ASAN_STACK_MAGIC_USE_AFTER_RET, ASAN_STACK_RETIRED_MAGIC): Define. From-SVN: r205476
This commit is contained in:
Jakub Jelinek
Jakub Jelinek
parent
8b5e12023b
commit
e361382f65
@ -1,3 +1,17 @@
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2013-11-28 Jakub Jelinek <jakub@redhat.com>
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* cfgexpand.c (struct stack_vars_data): Add asan_base and asan_alignb
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fields.
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(expand_stack_vars): For -fsanitize=address, use (and set initially)
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data->asan_base as base for vars and update asan_alignb.
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(expand_used_vars): Initialize data.asan_base and data.asan_alignb.
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Pass them to asan_emit_stack_protection.
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* asan.c (asan_detect_stack_use_after_return): New variable.
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(asan_emit_stack_protection): Add pbase and alignb arguments.
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Implement use after return sanitization.
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* asan.h (asan_emit_stack_protection): Adjust prototype.
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(ASAN_STACK_MAGIC_USE_AFTER_RET, ASAN_STACK_RETIRED_MAGIC): Define.
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2013-11-28 Sergey Ostanevich <sergos.gnu@gmail.com>
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* common.opt: Introduced a new option -fsimd-cost-model.
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129
gcc/asan.c
129
gcc/asan.c
@ -237,6 +237,9 @@ alias_set_type asan_shadow_set = -1;
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alias set is used for all shadow memory accesses. */
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static GTY(()) tree shadow_ptr_types[2];
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/* Decl for __asan_option_detect_stack_use_after_return. */
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static GTY(()) tree asan_detect_stack_use_after_return;
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/* Hashtable support for memory references used by gimple
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statements. */
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@ -950,20 +953,26 @@ asan_function_start (void)
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and DECLS is an array of representative decls for each var partition.
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LENGTH is the length of the OFFSETS array, DECLS array is LENGTH / 2 - 1
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elements long (OFFSETS include gap before the first variable as well
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as gaps after each stack variable). */
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as gaps after each stack variable). PBASE is, if non-NULL, some pseudo
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register which stack vars DECL_RTLs are based on. Either BASE should be
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assigned to PBASE, when not doing use after return protection, or
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corresponding address based on __asan_stack_malloc* return value. */
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rtx
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asan_emit_stack_protection (rtx base, HOST_WIDE_INT *offsets, tree *decls,
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int length)
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asan_emit_stack_protection (rtx base, rtx pbase, unsigned int alignb,
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HOST_WIDE_INT *offsets, tree *decls, int length)
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{
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rtx shadow_base, shadow_mem, ret, mem;
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rtx shadow_base, shadow_mem, ret, mem, orig_base, lab;
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char buf[30];
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unsigned char shadow_bytes[4];
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HOST_WIDE_INT base_offset = offsets[length - 1], offset, prev_offset;
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HOST_WIDE_INT base_offset = offsets[length - 1];
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HOST_WIDE_INT base_align_bias = 0, offset, prev_offset;
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HOST_WIDE_INT asan_frame_size = offsets[0] - base_offset;
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HOST_WIDE_INT last_offset, last_size;
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int l;
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unsigned char cur_shadow_byte = ASAN_STACK_MAGIC_LEFT;
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tree str_cst, decl, id;
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int use_after_return_class = -1;
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if (shadow_ptr_types[0] == NULL_TREE)
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asan_init_shadow_ptr_types ();
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@ -993,10 +1002,67 @@ asan_emit_stack_protection (rtx base, HOST_WIDE_INT *offsets, tree *decls,
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str_cst = asan_pp_string (&asan_pp);
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/* Emit the prologue sequence. */
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if (asan_frame_size > 32 && asan_frame_size <= 65536 && pbase)
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{
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use_after_return_class = floor_log2 (asan_frame_size - 1) - 5;
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/* __asan_stack_malloc_N guarantees alignment
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N < 6 ? (64 << N) : 4096 bytes. */
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if (alignb > (use_after_return_class < 6
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? (64U << use_after_return_class) : 4096U))
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use_after_return_class = -1;
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else if (alignb > ASAN_RED_ZONE_SIZE && (asan_frame_size & (alignb - 1)))
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base_align_bias = ((asan_frame_size + alignb - 1)
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& ~(alignb - HOST_WIDE_INT_1)) - asan_frame_size;
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}
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if (use_after_return_class == -1 && pbase)
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emit_move_insn (pbase, base);
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base = expand_binop (Pmode, add_optab, base,
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gen_int_mode (base_offset, Pmode),
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gen_int_mode (base_offset - base_align_bias, Pmode),
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NULL_RTX, 1, OPTAB_DIRECT);
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orig_base = NULL_RTX;
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if (use_after_return_class != -1)
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{
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if (asan_detect_stack_use_after_return == NULL_TREE)
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{
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id = get_identifier ("__asan_option_detect_stack_use_after_return");
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decl = build_decl (BUILTINS_LOCATION, VAR_DECL, id,
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integer_type_node);
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SET_DECL_ASSEMBLER_NAME (decl, id);
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TREE_ADDRESSABLE (decl) = 1;
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DECL_ARTIFICIAL (decl) = 1;
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DECL_IGNORED_P (decl) = 1;
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DECL_EXTERNAL (decl) = 1;
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TREE_STATIC (decl) = 1;
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TREE_PUBLIC (decl) = 1;
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TREE_USED (decl) = 1;
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asan_detect_stack_use_after_return = decl;
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}
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orig_base = gen_reg_rtx (Pmode);
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emit_move_insn (orig_base, base);
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ret = expand_normal (asan_detect_stack_use_after_return);
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lab = gen_label_rtx ();
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int very_likely = REG_BR_PROB_BASE - (REG_BR_PROB_BASE / 2000 - 1);
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emit_cmp_and_jump_insns (ret, const0_rtx, EQ, NULL_RTX,
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VOIDmode, 0, lab, very_likely);
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snprintf (buf, sizeof buf, "__asan_stack_malloc_%d",
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use_after_return_class);
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ret = init_one_libfunc (buf);
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rtx addr = convert_memory_address (ptr_mode, base);
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ret = emit_library_call_value (ret, NULL_RTX, LCT_NORMAL, ptr_mode, 2,
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GEN_INT (asan_frame_size
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+ base_align_bias),
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TYPE_MODE (pointer_sized_int_node),
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addr, ptr_mode);
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ret = convert_memory_address (Pmode, ret);
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emit_move_insn (base, ret);
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emit_label (lab);
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emit_move_insn (pbase, expand_binop (Pmode, add_optab, base,
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gen_int_mode (base_align_bias
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- base_offset, Pmode),
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NULL_RTX, 1, OPTAB_DIRECT));
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}
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mem = gen_rtx_MEM (ptr_mode, base);
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mem = adjust_address (mem, VOIDmode, base_align_bias);
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emit_move_insn (mem, gen_int_mode (ASAN_STACK_FRAME_MAGIC, ptr_mode));
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mem = adjust_address (mem, VOIDmode, GET_MODE_SIZE (ptr_mode));
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emit_move_insn (mem, expand_normal (str_cst));
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@ -1020,10 +1086,10 @@ asan_emit_stack_protection (rtx base, HOST_WIDE_INT *offsets, tree *decls,
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shadow_base = expand_binop (Pmode, lshr_optab, base,
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GEN_INT (ASAN_SHADOW_SHIFT),
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NULL_RTX, 1, OPTAB_DIRECT);
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shadow_base = expand_binop (Pmode, add_optab, shadow_base,
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gen_int_mode (targetm.asan_shadow_offset (),
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Pmode),
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NULL_RTX, 1, OPTAB_DIRECT);
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shadow_base
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= plus_constant (Pmode, shadow_base,
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targetm.asan_shadow_offset ()
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+ (base_align_bias >> ASAN_SHADOW_SHIFT));
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gcc_assert (asan_shadow_set != -1
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&& (ASAN_RED_ZONE_SIZE >> ASAN_SHADOW_SHIFT) == 4);
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shadow_mem = gen_rtx_MEM (SImode, shadow_base);
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@ -1074,6 +1140,47 @@ asan_emit_stack_protection (rtx base, HOST_WIDE_INT *offsets, tree *decls,
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/* Construct epilogue sequence. */
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start_sequence ();
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lab = NULL_RTX;
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if (use_after_return_class != -1)
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{
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rtx lab2 = gen_label_rtx ();
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char c = (char) ASAN_STACK_MAGIC_USE_AFTER_RET;
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int very_likely = REG_BR_PROB_BASE - (REG_BR_PROB_BASE / 2000 - 1);
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emit_cmp_and_jump_insns (orig_base, base, EQ, NULL_RTX,
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VOIDmode, 0, lab2, very_likely);
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shadow_mem = gen_rtx_MEM (BLKmode, shadow_base);
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set_mem_alias_set (shadow_mem, asan_shadow_set);
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mem = gen_rtx_MEM (ptr_mode, base);
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mem = adjust_address (mem, VOIDmode, base_align_bias);
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emit_move_insn (mem, gen_int_mode (ASAN_STACK_RETIRED_MAGIC, ptr_mode));
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unsigned HOST_WIDE_INT sz = asan_frame_size >> ASAN_SHADOW_SHIFT;
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if (use_after_return_class < 5
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&& can_store_by_pieces (sz, builtin_memset_read_str, &c,
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BITS_PER_UNIT, true))
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store_by_pieces (shadow_mem, sz, builtin_memset_read_str, &c,
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BITS_PER_UNIT, true, 0);
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else if (use_after_return_class >= 5
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|| !set_storage_via_setmem (shadow_mem,
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GEN_INT (sz),
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gen_int_mode (c, QImode),
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BITS_PER_UNIT, BITS_PER_UNIT,
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-1, sz, sz, sz))
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{
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snprintf (buf, sizeof buf, "__asan_stack_free_%d",
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use_after_return_class);
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ret = init_one_libfunc (buf);
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rtx addr = convert_memory_address (ptr_mode, base);
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rtx orig_addr = convert_memory_address (ptr_mode, orig_base);
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emit_library_call (ret, LCT_NORMAL, ptr_mode, 3, addr, ptr_mode,
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GEN_INT (asan_frame_size + base_align_bias),
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TYPE_MODE (pointer_sized_int_node),
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orig_addr, ptr_mode);
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}
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lab = gen_label_rtx ();
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emit_jump (lab);
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emit_label (lab2);
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}
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shadow_mem = gen_rtx_MEM (BLKmode, shadow_base);
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set_mem_alias_set (shadow_mem, asan_shadow_set);
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prev_offset = base_offset;
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@ -1106,6 +1213,8 @@ asan_emit_stack_protection (rtx base, HOST_WIDE_INT *offsets, tree *decls,
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}
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do_pending_stack_adjust ();
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if (lab)
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emit_label (lab);
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ret = get_insns ();
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end_sequence ();
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@ -23,7 +23,8 @@ along with GCC; see the file COPYING3. If not see
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extern void asan_function_start (void);
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extern void asan_finish_file (void);
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extern rtx asan_emit_stack_protection (rtx, HOST_WIDE_INT *, tree *, int);
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extern rtx asan_emit_stack_protection (rtx, rtx, unsigned int, HOST_WIDE_INT *,
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tree *, int);
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extern bool asan_protect_global (tree);
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extern void initialize_sanitizer_builtins (void);
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extern tree asan_dynamic_init_call (bool);
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@ -49,8 +50,10 @@ extern alias_set_type asan_shadow_set;
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#define ASAN_STACK_MAGIC_MIDDLE 0xf2
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#define ASAN_STACK_MAGIC_RIGHT 0xf3
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#define ASAN_STACK_MAGIC_PARTIAL 0xf4
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#define ASAN_STACK_MAGIC_USE_AFTER_RET 0xf5
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#define ASAN_STACK_FRAME_MAGIC 0x41b58ab3
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#define ASAN_STACK_RETIRED_MAGIC 0x45e0360e
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/* Return true if DECL should be guarded on the stack. */
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@ -890,6 +890,12 @@ struct stack_vars_data
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/* Vector of partition representative decls in between the paddings. */
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vec<tree> asan_decl_vec;
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/* Base pseudo register for Address Sanitizer protected automatic vars. */
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rtx asan_base;
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/* Alignment needed for the Address Sanitizer protected automatic vars. */
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unsigned int asan_alignb;
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};
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/* A subroutine of expand_used_vars. Give each partition representative
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@ -974,6 +980,7 @@ expand_stack_vars (bool (*pred) (size_t), struct stack_vars_data *data)
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alignb = stack_vars[i].alignb;
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if (alignb * BITS_PER_UNIT <= MAX_SUPPORTED_STACK_ALIGNMENT)
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{
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base = virtual_stack_vars_rtx;
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if ((flag_sanitize & SANITIZE_ADDRESS) && pred)
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{
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HOST_WIDE_INT prev_offset = frame_offset;
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@ -1002,10 +1009,13 @@ expand_stack_vars (bool (*pred) (size_t), struct stack_vars_data *data)
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if (repr_decl == NULL_TREE)
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repr_decl = stack_vars[i].decl;
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data->asan_decl_vec.safe_push (repr_decl);
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data->asan_alignb = MAX (data->asan_alignb, alignb);
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if (data->asan_base == NULL)
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data->asan_base = gen_reg_rtx (Pmode);
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base = data->asan_base;
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}
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else
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offset = alloc_stack_frame_space (stack_vars[i].size, alignb);
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base = virtual_stack_vars_rtx;
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base_align = crtl->max_used_stack_slot_alignment;
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}
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else
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@ -1792,6 +1802,8 @@ expand_used_vars (void)
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data.asan_vec = vNULL;
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data.asan_decl_vec = vNULL;
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data.asan_base = NULL_RTX;
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data.asan_alignb = 0;
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/* Reorder decls to be protected by iterating over the variables
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array multiple times, and allocating out of each phase in turn. */
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@ -1816,14 +1828,23 @@ expand_used_vars (void)
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if (!data.asan_vec.is_empty ())
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{
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HOST_WIDE_INT prev_offset = frame_offset;
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HOST_WIDE_INT offset
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= alloc_stack_frame_space (ASAN_RED_ZONE_SIZE,
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ASAN_RED_ZONE_SIZE);
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HOST_WIDE_INT offset, sz, redzonesz;
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redzonesz = ASAN_RED_ZONE_SIZE;
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sz = data.asan_vec[0] - prev_offset;
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if (data.asan_alignb > ASAN_RED_ZONE_SIZE
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&& data.asan_alignb <= 4096
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&& sz + ASAN_RED_ZONE_SIZE >= data.asan_alignb)
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redzonesz = ((sz + ASAN_RED_ZONE_SIZE + data.asan_alignb - 1)
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& ~(data.asan_alignb - HOST_WIDE_INT_1)) - sz;
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offset
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= alloc_stack_frame_space (redzonesz, ASAN_RED_ZONE_SIZE);
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data.asan_vec.safe_push (prev_offset);
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data.asan_vec.safe_push (offset);
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var_end_seq
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= asan_emit_stack_protection (virtual_stack_vars_rtx,
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data.asan_base,
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data.asan_alignb,
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data.asan_vec.address (),
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data.asan_decl_vec.address (),
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data.asan_vec.length ());
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