| /* Pointer Bounds Checker optimization pass. |
| Copyright (C) 2014-2017 Free Software Foundation, Inc. |
| Contributed by Ilya Enkovich (ilya.enkovich@intel.com) |
| |
| This file is part of GCC. |
| |
| GCC 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. |
| |
| GCC 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 GCC; see the file COPYING3. If not see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include "config.h" |
| #include "system.h" |
| #include "coretypes.h" |
| #include "backend.h" |
| #include "target.h" |
| #include "rtl.h" |
| #include "tree.h" |
| #include "gimple.h" |
| #include "tree-pass.h" |
| #include "ssa.h" |
| #include "gimple-pretty-print.h" |
| #include "diagnostic.h" |
| #include "fold-const.h" |
| #include "tree-cfg.h" |
| #include "tree-ssa-loop-niter.h" |
| #include "gimple-iterator.h" |
| #include "tree-chkp.h" |
| #include "ipa-chkp.h" |
| |
| enum check_type |
| { |
| CHECK_LOWER_BOUND, |
| CHECK_UPPER_BOUND |
| }; |
| |
| struct pol_item |
| { |
| tree cst; |
| tree var; |
| }; |
| |
| struct address_t |
| { |
| vec<struct pol_item> pol; |
| }; |
| |
| /* Structure to hold check informtation. */ |
| struct check_info |
| { |
| /* Type of the check. */ |
| check_type type; |
| /* Address used for the check. */ |
| address_t addr; |
| /* Bounds used for the check. */ |
| tree bounds; |
| /* Check statement. Can be NULL for removed checks. */ |
| gimple *stmt; |
| }; |
| |
| /* Structure to hold checks information for BB. */ |
| struct bb_checks |
| { |
| vec<struct check_info, va_heap, vl_ptr> checks; |
| }; |
| |
| static void chkp_collect_value (tree ssa_name, address_t &res); |
| |
| #define chkp_bndmk_fndecl \ |
| (targetm.builtin_chkp_function (BUILT_IN_CHKP_BNDMK)) |
| #define chkp_intersect_fndecl \ |
| (targetm.builtin_chkp_function (BUILT_IN_CHKP_INTERSECT)) |
| #define chkp_checkl_fndecl \ |
| (targetm.builtin_chkp_function (BUILT_IN_CHKP_BNDCL)) |
| #define chkp_checku_fndecl \ |
| (targetm.builtin_chkp_function (BUILT_IN_CHKP_BNDCU)) |
| |
| static vec<struct bb_checks, va_heap, vl_ptr> check_infos; |
| |
| /* Comparator for pol_item structures I1 and I2 to be used |
| to find items with equal var. Also used for polynomial |
| sorting. */ |
| static int |
| chkp_pol_item_compare (const void *i1, const void *i2) |
| { |
| const struct pol_item *p1 = (const struct pol_item *)i1; |
| const struct pol_item *p2 = (const struct pol_item *)i2; |
| |
| if (p1->var == p2->var) |
| return 0; |
| else if (p1->var > p2->var) |
| return 1; |
| else |
| return -1; |
| } |
| |
| /* Find polynomial item in ADDR with var equal to VAR |
| and return its index. Return -1 if item was not |
| found. */ |
| static int |
| chkp_pol_find (address_t &addr, tree var) |
| { |
| int left = 0; |
| int right = addr.pol.length () - 1; |
| int n; |
| |
| while (right >= left) |
| { |
| n = (left + right) / 2; |
| |
| if (addr.pol[n].var == var |
| || (var && addr.pol[n].var |
| && TREE_CODE (var) == ADDR_EXPR |
| && TREE_CODE (addr.pol[n].var) == ADDR_EXPR |
| && TREE_OPERAND (var, 0) == TREE_OPERAND (addr.pol[n].var, 0))) |
| return n; |
| else if (addr.pol[n].var > var) |
| right = n - 1; |
| else |
| left = n + 1; |
| } |
| |
| return -1; |
| } |
| |
| /* Return constant CST extended to size type. */ |
| static tree |
| chkp_extend_const (tree cst) |
| { |
| if (TYPE_PRECISION (TREE_TYPE (cst)) < TYPE_PRECISION (size_type_node)) |
| return build_int_cst_type (size_type_node, tree_to_shwi (cst)); |
| |
| return cst; |
| } |
| |
| /* Add polynomial item CST * VAR to ADDR. */ |
| static void |
| chkp_add_addr_item (address_t &addr, tree cst, tree var) |
| { |
| int n = chkp_pol_find (addr, var); |
| |
| cst = chkp_extend_const (cst); |
| |
| if (n < 0) |
| { |
| struct pol_item item; |
| item.cst = cst; |
| item.var = var; |
| |
| addr.pol.safe_push (item); |
| addr.pol.qsort (&chkp_pol_item_compare); |
| } |
| else |
| { |
| addr.pol[n].cst = fold_build2 (PLUS_EXPR, TREE_TYPE (addr.pol[n].cst), |
| addr.pol[n].cst, cst); |
| if (TREE_CODE (addr.pol[n].cst) == INTEGER_CST |
| && integer_zerop (addr.pol[n].cst)) |
| addr.pol.ordered_remove (n); |
| } |
| } |
| |
| /* Subtract polynomial item CST * VAR from ADDR. */ |
| static void |
| chkp_sub_addr_item (address_t &addr, tree cst, tree var) |
| { |
| int n = chkp_pol_find (addr, var); |
| |
| cst = chkp_extend_const (cst); |
| |
| if (n < 0) |
| { |
| struct pol_item item; |
| item.cst = fold_build2 (MINUS_EXPR, TREE_TYPE (cst), |
| integer_zero_node, cst); |
| item.var = var; |
| |
| addr.pol.safe_push (item); |
| addr.pol.qsort (&chkp_pol_item_compare); |
| } |
| else |
| { |
| addr.pol[n].cst = fold_build2 (MINUS_EXPR, TREE_TYPE (addr.pol[n].cst), |
| addr.pol[n].cst, cst); |
| if (TREE_CODE (addr.pol[n].cst) == INTEGER_CST |
| && integer_zerop (addr.pol[n].cst)) |
| addr.pol.ordered_remove (n); |
| } |
| } |
| |
| /* Add address DELTA to ADDR. */ |
| static void |
| chkp_add_addr_addr (address_t &addr, address_t &delta) |
| { |
| unsigned int i; |
| for (i = 0; i < delta.pol.length (); i++) |
| chkp_add_addr_item (addr, delta.pol[i].cst, delta.pol[i].var); |
| } |
| |
| /* Subtract address DELTA from ADDR. */ |
| static void |
| chkp_sub_addr_addr (address_t &addr, address_t &delta) |
| { |
| unsigned int i; |
| for (i = 0; i < delta.pol.length (); i++) |
| chkp_sub_addr_item (addr, delta.pol[i].cst, delta.pol[i].var); |
| } |
| |
| /* Mutiply address ADDR by integer constant MULT. */ |
| static void |
| chkp_mult_addr (address_t &addr, tree mult) |
| { |
| unsigned int i; |
| for (i = 0; i < addr.pol.length (); i++) |
| addr.pol[i].cst = fold_build2 (MULT_EXPR, TREE_TYPE (addr.pol[i].cst), |
| addr.pol[i].cst, mult); |
| } |
| |
| /* Return 1 if we may prove ADDR has a constant value with |
| determined sign, which is put into *SIGN. Otherwise |
| return 0. */ |
| static bool |
| chkp_is_constant_addr (const address_t &addr, int *sign) |
| { |
| *sign = 0; |
| |
| if (addr.pol.length () == 0) |
| return true; |
| else if (addr.pol.length () > 1) |
| return false; |
| else if (addr.pol[0].var) |
| return false; |
| else if (TREE_CODE (addr.pol[0].cst) != INTEGER_CST) |
| return false; |
| else if (integer_zerop (addr.pol[0].cst)) |
| *sign = 0; |
| else if (tree_int_cst_sign_bit (addr.pol[0].cst)) |
| *sign = -1; |
| else |
| *sign = 1; |
| |
| return true; |
| } |
| |
| /* Dump ADDR into dump_file. */ |
| static void |
| chkp_print_addr (const address_t &addr) |
| { |
| unsigned int n = 0; |
| for (n = 0; n < addr.pol.length (); n++) |
| { |
| if (n > 0) |
| fprintf (dump_file, " + "); |
| |
| if (addr.pol[n].var == NULL_TREE) |
| print_generic_expr (dump_file, addr.pol[n].cst); |
| else |
| { |
| if (TREE_CODE (addr.pol[n].cst) != INTEGER_CST |
| || !integer_onep (addr.pol[n].cst)) |
| { |
| print_generic_expr (dump_file, addr.pol[n].cst); |
| fprintf (dump_file, " * "); |
| } |
| print_generic_expr (dump_file, addr.pol[n].var); |
| } |
| } |
| } |
| |
| /* Compute value of PTR and put it into address RES. |
| PTR has to be ADDR_EXPR. */ |
| static void |
| chkp_collect_addr_value (tree ptr, address_t &res) |
| { |
| tree obj = TREE_OPERAND (ptr, 0); |
| address_t addr; |
| |
| switch (TREE_CODE (obj)) |
| { |
| case INDIRECT_REF: |
| chkp_collect_value (TREE_OPERAND (obj, 0), res); |
| break; |
| |
| case MEM_REF: |
| chkp_collect_value (TREE_OPERAND (obj, 0), res); |
| addr.pol.create (0); |
| chkp_collect_value (TREE_OPERAND (obj, 1), addr); |
| chkp_add_addr_addr (res, addr); |
| addr.pol.release (); |
| break; |
| |
| case ARRAY_REF: |
| chkp_collect_value (build_fold_addr_expr (TREE_OPERAND (obj, 0)), res); |
| addr.pol.create (0); |
| chkp_collect_value (TREE_OPERAND (obj, 1), addr); |
| chkp_mult_addr (addr, array_ref_element_size (obj)); |
| chkp_add_addr_addr (res, addr); |
| addr.pol.release (); |
| break; |
| |
| case COMPONENT_REF: |
| { |
| tree str = TREE_OPERAND (obj, 0); |
| tree field = TREE_OPERAND (obj, 1); |
| chkp_collect_value (build_fold_addr_expr (str), res); |
| addr.pol.create (0); |
| chkp_collect_value (component_ref_field_offset (obj), addr); |
| chkp_add_addr_addr (res, addr); |
| addr.pol.release (); |
| if (DECL_FIELD_BIT_OFFSET (field)) |
| { |
| addr.pol.create (0); |
| chkp_collect_value (fold_build2 (TRUNC_DIV_EXPR, size_type_node, |
| DECL_FIELD_BIT_OFFSET (field), |
| size_int (BITS_PER_UNIT)), |
| addr); |
| chkp_add_addr_addr (res, addr); |
| addr.pol.release (); |
| } |
| } |
| break; |
| |
| default: |
| chkp_add_addr_item (res, integer_one_node, ptr); |
| break; |
| } |
| } |
| |
| /* Compute value of PTR and put it into address RES. */ |
| static void |
| chkp_collect_value (tree ptr, address_t &res) |
| { |
| gimple *def_stmt; |
| enum gimple_code code; |
| enum tree_code rhs_code; |
| address_t addr; |
| tree rhs1; |
| |
| if (TREE_CODE (ptr) == INTEGER_CST) |
| { |
| chkp_add_addr_item (res, ptr, NULL); |
| return; |
| } |
| else if (TREE_CODE (ptr) == ADDR_EXPR) |
| { |
| chkp_collect_addr_value (ptr, res); |
| return; |
| } |
| else if (TREE_CODE (ptr) != SSA_NAME) |
| { |
| chkp_add_addr_item (res, integer_one_node, ptr); |
| return; |
| } |
| |
| /* Now we handle the case when polynomial is computed |
| for SSA NAME. */ |
| def_stmt = SSA_NAME_DEF_STMT (ptr); |
| code = gimple_code (def_stmt); |
| |
| /* Currently we do not walk through statements other |
| than assignment. */ |
| if (code != GIMPLE_ASSIGN) |
| { |
| chkp_add_addr_item (res, integer_one_node, ptr); |
| return; |
| } |
| |
| rhs_code = gimple_assign_rhs_code (def_stmt); |
| rhs1 = gimple_assign_rhs1 (def_stmt); |
| |
| switch (rhs_code) |
| { |
| case SSA_NAME: |
| case INTEGER_CST: |
| case ADDR_EXPR: |
| chkp_collect_value (rhs1, res); |
| break; |
| |
| case PLUS_EXPR: |
| case POINTER_PLUS_EXPR: |
| chkp_collect_value (rhs1, res); |
| addr.pol.create (0); |
| chkp_collect_value (gimple_assign_rhs2 (def_stmt), addr); |
| chkp_add_addr_addr (res, addr); |
| addr.pol.release (); |
| break; |
| |
| case MINUS_EXPR: |
| chkp_collect_value (rhs1, res); |
| addr.pol.create (0); |
| chkp_collect_value (gimple_assign_rhs2 (def_stmt), addr); |
| chkp_sub_addr_addr (res, addr); |
| addr.pol.release (); |
| break; |
| |
| case MULT_EXPR: |
| if (TREE_CODE (rhs1) == SSA_NAME |
| && TREE_CODE (gimple_assign_rhs2 (def_stmt)) == INTEGER_CST) |
| { |
| chkp_collect_value (rhs1, res); |
| chkp_mult_addr (res, gimple_assign_rhs2 (def_stmt)); |
| } |
| else if (TREE_CODE (gimple_assign_rhs2 (def_stmt)) == SSA_NAME |
| && TREE_CODE (rhs1) == INTEGER_CST) |
| { |
| chkp_collect_value (gimple_assign_rhs2 (def_stmt), res); |
| chkp_mult_addr (res, rhs1); |
| } |
| else |
| chkp_add_addr_item (res, integer_one_node, ptr); |
| break; |
| |
| default: |
| chkp_add_addr_item (res, integer_one_node, ptr); |
| break; |
| } |
| } |
| |
| /* Fill check_info structure *CI with information about |
| check STMT. */ |
| static void |
| chkp_fill_check_info (gimple *stmt, struct check_info *ci) |
| { |
| ci->addr.pol.create (0); |
| ci->bounds = gimple_call_arg (stmt, 1); |
| chkp_collect_value (gimple_call_arg (stmt, 0), ci->addr); |
| ci->type = (gimple_call_fndecl (stmt) == chkp_checkl_fndecl |
| ? CHECK_LOWER_BOUND |
| : CHECK_UPPER_BOUND); |
| ci->stmt = stmt; |
| } |
| |
| /* Release structures holding check information |
| for current function. */ |
| static void |
| chkp_release_check_info (void) |
| { |
| unsigned int n, m; |
| |
| if (check_infos.exists ()) |
| { |
| for (n = 0; n < check_infos.length (); n++) |
| { |
| for (m = 0; m < check_infos[n].checks.length (); m++) |
| if (check_infos[n].checks[m].addr.pol.exists ()) |
| check_infos[n].checks[m].addr.pol.release (); |
| check_infos[n].checks.release (); |
| } |
| check_infos.release (); |
| } |
| } |
| |
| /* Create structures to hold check information |
| for current function. */ |
| static void |
| chkp_init_check_info (void) |
| { |
| struct bb_checks empty_bbc; |
| int n; |
| |
| empty_bbc.checks = vNULL; |
| |
| chkp_release_check_info (); |
| |
| check_infos.create (last_basic_block_for_fn (cfun)); |
| for (n = 0; n < last_basic_block_for_fn (cfun); n++) |
| { |
| check_infos.safe_push (empty_bbc); |
| check_infos.last ().checks.create (0); |
| } |
| } |
| |
| /* Find all checks in current function and store info about them |
| in check_infos. */ |
| static void |
| chkp_gather_checks_info (void) |
| { |
| basic_block bb; |
| gimple_stmt_iterator i; |
| |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, "Gathering information about checks...\n"); |
| |
| chkp_init_check_info (); |
| |
| FOR_EACH_BB_FN (bb, cfun) |
| { |
| struct bb_checks *bbc = &check_infos[bb->index]; |
| |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, "Searching checks in BB%d...\n", bb->index); |
| |
| for (i = gsi_start_bb (bb); !gsi_end_p (i); gsi_next (&i)) |
| { |
| gimple *stmt = gsi_stmt (i); |
| |
| if (gimple_code (stmt) != GIMPLE_CALL) |
| continue; |
| |
| if (gimple_call_fndecl (stmt) == chkp_checkl_fndecl |
| || gimple_call_fndecl (stmt) == chkp_checku_fndecl) |
| { |
| struct check_info ci; |
| |
| chkp_fill_check_info (stmt, &ci); |
| bbc->checks.safe_push (ci); |
| |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| { |
| fprintf (dump_file, "Adding check information:\n"); |
| fprintf (dump_file, " bounds: "); |
| print_generic_expr (dump_file, ci.bounds); |
| fprintf (dump_file, "\n address: "); |
| chkp_print_addr (ci.addr); |
| fprintf (dump_file, "\n check: "); |
| print_gimple_stmt (dump_file, stmt, 0); |
| } |
| } |
| } |
| } |
| } |
| |
| /* Return 1 if check CI against BOUNDS always pass, |
| -1 if check CI against BOUNDS always fails and |
| 0 if we cannot compute check result. */ |
| static int |
| chkp_get_check_result (struct check_info *ci, tree bounds) |
| { |
| gimple *bnd_def; |
| address_t bound_val; |
| int sign, res = 0; |
| |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| { |
| fprintf (dump_file, "Trying to compute result of the check\n"); |
| fprintf (dump_file, " check: "); |
| print_gimple_stmt (dump_file, ci->stmt, 0); |
| fprintf (dump_file, " address: "); |
| chkp_print_addr (ci->addr); |
| fprintf (dump_file, "\n bounds: "); |
| print_generic_expr (dump_file, bounds); |
| fprintf (dump_file, "\n"); |
| } |
| |
| if (TREE_CODE (bounds) != SSA_NAME) |
| { |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, " result: bounds tree code is not ssa_name\n"); |
| return 0; |
| } |
| |
| bnd_def = SSA_NAME_DEF_STMT (bounds); |
| /* Currently we handle cases when bounds are result of bndmk |
| or loaded static bounds var. */ |
| if (gimple_code (bnd_def) == GIMPLE_CALL |
| && gimple_call_fndecl (bnd_def) == chkp_bndmk_fndecl) |
| { |
| bound_val.pol.create (0); |
| chkp_collect_value (gimple_call_arg (bnd_def, 0), bound_val); |
| if (ci->type == CHECK_UPPER_BOUND) |
| { |
| address_t size_val; |
| size_val.pol.create (0); |
| chkp_collect_value (gimple_call_arg (bnd_def, 1), size_val); |
| chkp_add_addr_addr (bound_val, size_val); |
| size_val.pol.release (); |
| chkp_add_addr_item (bound_val, integer_minus_one_node, NULL); |
| } |
| } |
| else if (gimple_code (bnd_def) == GIMPLE_ASSIGN |
| && gimple_assign_rhs1 (bnd_def) == chkp_get_zero_bounds_var ()) |
| { |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, " result: always pass with zero bounds\n"); |
| return 1; |
| } |
| else if (gimple_code (bnd_def) == GIMPLE_ASSIGN |
| && gimple_assign_rhs1 (bnd_def) == chkp_get_none_bounds_var ()) |
| { |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, " result: always fails with none bounds\n"); |
| return -1; |
| } |
| else if (gimple_code (bnd_def) == GIMPLE_ASSIGN |
| && TREE_CODE (gimple_assign_rhs1 (bnd_def)) == VAR_DECL) |
| { |
| tree bnd_var = gimple_assign_rhs1 (bnd_def); |
| tree var; |
| tree size; |
| |
| if (!DECL_INITIAL (bnd_var) |
| || DECL_INITIAL (bnd_var) == error_mark_node) |
| { |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, " result: cannot compute bounds\n"); |
| return 0; |
| } |
| |
| gcc_assert (TREE_CODE (DECL_INITIAL (bnd_var)) == ADDR_EXPR); |
| var = TREE_OPERAND (DECL_INITIAL (bnd_var), 0); |
| |
| bound_val.pol.create (0); |
| chkp_collect_value (DECL_INITIAL (bnd_var), bound_val); |
| if (ci->type == CHECK_UPPER_BOUND) |
| { |
| if (VAR_P (var)) |
| { |
| if (DECL_SIZE (var) |
| && !chkp_variable_size_type (TREE_TYPE (var))) |
| size = DECL_SIZE_UNIT (var); |
| else |
| { |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, " result: cannot compute bounds\n"); |
| return 0; |
| } |
| } |
| else |
| { |
| gcc_assert (TREE_CODE (var) == STRING_CST); |
| size = build_int_cst (size_type_node, |
| TREE_STRING_LENGTH (var)); |
| } |
| |
| address_t size_val; |
| size_val.pol.create (0); |
| chkp_collect_value (size, size_val); |
| chkp_add_addr_addr (bound_val, size_val); |
| size_val.pol.release (); |
| chkp_add_addr_item (bound_val, integer_minus_one_node, NULL); |
| } |
| } |
| else |
| { |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, " result: cannot compute bounds\n"); |
| return 0; |
| } |
| |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| { |
| fprintf (dump_file, " bound value: "); |
| chkp_print_addr (bound_val); |
| fprintf (dump_file, "\n"); |
| } |
| |
| chkp_sub_addr_addr (bound_val, ci->addr); |
| |
| if (!chkp_is_constant_addr (bound_val, &sign)) |
| { |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, " result: cannot compute result\n"); |
| |
| res = 0; |
| } |
| else if (sign == 0 |
| || (ci->type == CHECK_UPPER_BOUND && sign > 0) |
| || (ci->type == CHECK_LOWER_BOUND && sign < 0)) |
| { |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, " result: always pass\n"); |
| |
| res = 1; |
| } |
| else |
| { |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, " result: always fail\n"); |
| |
| res = -1; |
| } |
| |
| bound_val.pol.release (); |
| |
| return res; |
| } |
| |
| /* Try to compare bounds value and address value |
| used in the check CI. If we can prove that check |
| always pass then remove it. */ |
| static void |
| chkp_remove_check_if_pass (struct check_info *ci) |
| { |
| int result = 0; |
| |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| { |
| fprintf (dump_file, "Trying to remove check: "); |
| print_gimple_stmt (dump_file, ci->stmt, 0); |
| } |
| |
| result = chkp_get_check_result (ci, ci->bounds); |
| |
| if (result == 1) |
| { |
| gimple_stmt_iterator i = gsi_for_stmt (ci->stmt); |
| |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, " action: delete check (always pass)\n"); |
| |
| gsi_remove (&i, true); |
| unlink_stmt_vdef (ci->stmt); |
| release_defs (ci->stmt); |
| ci->stmt = NULL; |
| } |
| else if (result == -1) |
| { |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, " action: keep check (always fail)\n"); |
| warning_at (gimple_location (ci->stmt), OPT_Wchkp, |
| "memory access check always fail"); |
| } |
| else if (result == 0) |
| { |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, " action: keep check (cannot compute result)\n"); |
| } |
| } |
| |
| /* For bounds used in CI check if bounds are produced by |
| intersection and we may use outer bounds instead. If |
| transformation is possible then fix check statement and |
| recompute its info. */ |
| static void |
| chkp_use_outer_bounds_if_possible (struct check_info *ci) |
| { |
| gimple *bnd_def; |
| tree bnd1, bnd2, bnd_res = NULL; |
| int check_res1, check_res2; |
| |
| if (TREE_CODE (ci->bounds) != SSA_NAME) |
| return; |
| |
| bnd_def = SSA_NAME_DEF_STMT (ci->bounds); |
| if (gimple_code (bnd_def) != GIMPLE_CALL |
| || gimple_call_fndecl (bnd_def) != chkp_intersect_fndecl) |
| return; |
| |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| { |
| fprintf (dump_file, "Check if bounds intersection is redundant: \n"); |
| fprintf (dump_file, " check: "); |
| print_gimple_stmt (dump_file, ci->stmt, 0); |
| fprintf (dump_file, " intersection: "); |
| print_gimple_stmt (dump_file, bnd_def, 0); |
| fprintf (dump_file, "\n"); |
| } |
| |
| bnd1 = gimple_call_arg (bnd_def, 0); |
| bnd2 = gimple_call_arg (bnd_def, 1); |
| |
| check_res1 = chkp_get_check_result (ci, bnd1); |
| check_res2 = chkp_get_check_result (ci, bnd2); |
| if (check_res1 == 1) |
| bnd_res = bnd2; |
| else if (check_res1 == -1) |
| bnd_res = bnd1; |
| else if (check_res2 == 1) |
| bnd_res = bnd1; |
| else if (check_res2 == -1) |
| bnd_res = bnd2; |
| |
| if (bnd_res) |
| { |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| { |
| fprintf (dump_file, " action: use "); |
| print_generic_expr (dump_file, bnd2); |
| fprintf (dump_file, " instead of "); |
| print_generic_expr (dump_file, ci->bounds); |
| fprintf (dump_file, "\n"); |
| } |
| |
| ci->bounds = bnd_res; |
| gimple_call_set_arg (ci->stmt, 1, bnd_res); |
| update_stmt (ci->stmt); |
| chkp_fill_check_info (ci->stmt, ci); |
| } |
| } |
| |
| /* Try to find checks whose bounds were produced by intersection |
| which does not affect check result. In such check outer bounds |
| are used instead. It allows to remove excess intersections |
| and helps to compare checks. */ |
| static void |
| chkp_remove_excess_intersections (void) |
| { |
| basic_block bb; |
| |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, "Searching for redundant bounds intersections...\n"); |
| |
| FOR_EACH_BB_FN (bb, cfun) |
| { |
| struct bb_checks *bbc = &check_infos[bb->index]; |
| unsigned int no; |
| |
| /* Iterate through all found checks in BB. */ |
| for (no = 0; no < bbc->checks.length (); no++) |
| if (bbc->checks[no].stmt) |
| chkp_use_outer_bounds_if_possible (&bbc->checks[no]); |
| } |
| } |
| |
| /* Try to remove all checks which are known to alwyas pass. */ |
| static void |
| chkp_remove_constant_checks (void) |
| { |
| basic_block bb; |
| |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, "Searching for redundant checks...\n"); |
| |
| FOR_EACH_BB_FN (bb, cfun) |
| { |
| struct bb_checks *bbc = &check_infos[bb->index]; |
| unsigned int no; |
| |
| /* Iterate through all found checks in BB. */ |
| for (no = 0; no < bbc->checks.length (); no++) |
| if (bbc->checks[no].stmt) |
| chkp_remove_check_if_pass (&bbc->checks[no]); |
| } |
| } |
| |
| /* Return fast version of string function FNCODE. */ |
| static tree |
| chkp_get_nobnd_fndecl (enum built_in_function fncode) |
| { |
| /* Check if we are allowed to use fast string functions. */ |
| if (!flag_chkp_use_fast_string_functions) |
| return NULL_TREE; |
| |
| tree fndecl = NULL_TREE; |
| |
| switch (fncode) |
| { |
| case BUILT_IN_MEMCPY_CHKP: |
| fndecl = builtin_decl_implicit (BUILT_IN_CHKP_MEMCPY_NOBND); |
| break; |
| |
| case BUILT_IN_MEMPCPY_CHKP: |
| fndecl = builtin_decl_implicit (BUILT_IN_CHKP_MEMPCPY_NOBND); |
| break; |
| |
| case BUILT_IN_MEMMOVE_CHKP: |
| fndecl = builtin_decl_implicit (BUILT_IN_CHKP_MEMMOVE_NOBND); |
| break; |
| |
| case BUILT_IN_MEMSET_CHKP: |
| fndecl = builtin_decl_implicit (BUILT_IN_CHKP_MEMSET_NOBND); |
| break; |
| |
| case BUILT_IN_CHKP_MEMCPY_NOCHK_CHKP: |
| fndecl = builtin_decl_implicit (BUILT_IN_CHKP_MEMCPY_NOBND_NOCHK); |
| break; |
| |
| case BUILT_IN_CHKP_MEMPCPY_NOCHK_CHKP: |
| fndecl = builtin_decl_implicit (BUILT_IN_CHKP_MEMPCPY_NOBND_NOCHK); |
| break; |
| |
| case BUILT_IN_CHKP_MEMMOVE_NOCHK_CHKP: |
| fndecl = builtin_decl_implicit (BUILT_IN_CHKP_MEMMOVE_NOBND_NOCHK); |
| break; |
| |
| case BUILT_IN_CHKP_MEMSET_NOCHK_CHKP: |
| fndecl = builtin_decl_implicit (BUILT_IN_CHKP_MEMSET_NOBND_NOCHK); |
| break; |
| |
| default: |
| break; |
| } |
| |
| if (fndecl) |
| fndecl = chkp_maybe_clone_builtin_fndecl (fndecl); |
| |
| return fndecl; |
| } |
| |
| |
| /* Return no-check version of string function FNCODE. */ |
| static tree |
| chkp_get_nochk_fndecl (enum built_in_function fncode) |
| { |
| /* Check if we are allowed to use fast string functions. */ |
| if (!flag_chkp_use_nochk_string_functions) |
| return NULL_TREE; |
| |
| tree fndecl = NULL_TREE; |
| |
| switch (fncode) |
| { |
| case BUILT_IN_MEMCPY_CHKP: |
| fndecl = builtin_decl_implicit (BUILT_IN_CHKP_MEMCPY_NOCHK); |
| break; |
| |
| case BUILT_IN_MEMPCPY_CHKP: |
| fndecl = builtin_decl_implicit (BUILT_IN_CHKP_MEMPCPY_NOCHK); |
| break; |
| |
| case BUILT_IN_MEMMOVE_CHKP: |
| fndecl = builtin_decl_implicit (BUILT_IN_CHKP_MEMMOVE_NOCHK); |
| break; |
| |
| case BUILT_IN_MEMSET_CHKP: |
| fndecl = builtin_decl_implicit (BUILT_IN_CHKP_MEMSET_NOCHK); |
| break; |
| |
| case BUILT_IN_CHKP_MEMCPY_NOBND_CHKP: |
| fndecl = builtin_decl_implicit (BUILT_IN_CHKP_MEMCPY_NOBND_NOCHK); |
| break; |
| |
| case BUILT_IN_CHKP_MEMPCPY_NOBND_CHKP: |
| fndecl = builtin_decl_implicit (BUILT_IN_CHKP_MEMPCPY_NOBND_NOCHK); |
| break; |
| |
| case BUILT_IN_CHKP_MEMMOVE_NOBND_CHKP: |
| fndecl = builtin_decl_implicit (BUILT_IN_CHKP_MEMMOVE_NOBND_NOCHK); |
| break; |
| |
| case BUILT_IN_CHKP_MEMSET_NOBND_CHKP: |
| fndecl = builtin_decl_implicit (BUILT_IN_CHKP_MEMSET_NOBND_NOCHK); |
| break; |
| |
| default: |
| break; |
| } |
| |
| if (fndecl) |
| fndecl = chkp_maybe_clone_builtin_fndecl (fndecl); |
| |
| return fndecl; |
| } |
| |
| /* Find memcpy, mempcpy, memmove and memset calls, perform |
| checks before call and then call no_chk version of |
| functions. We do it on O2 to enable inlining of these |
| functions during expand. |
| |
| Also try to find memcpy, mempcpy, memmove and memset calls |
| which are known to not write pointers to memory and use |
| faster function versions for them. */ |
| static void |
| chkp_optimize_string_function_calls (void) |
| { |
| basic_block bb; |
| |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, "Searching for replaceable string function calls...\n"); |
| |
| FOR_EACH_BB_FN (bb, cfun) |
| { |
| gimple_stmt_iterator i; |
| |
| for (i = gsi_start_bb (bb); !gsi_end_p (i); gsi_next (&i)) |
| { |
| gimple *stmt = gsi_stmt (i); |
| tree fndecl; |
| |
| if (!is_gimple_call (stmt) |
| || !gimple_call_with_bounds_p (stmt) |
| || !gimple_call_builtin_p (stmt, BUILT_IN_NORMAL)) |
| continue; |
| |
| fndecl = gimple_call_fndecl (stmt); |
| if (DECL_FUNCTION_CODE (fndecl) == BUILT_IN_MEMCPY_CHKP |
| || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_MEMPCPY_CHKP |
| || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_MEMMOVE_CHKP |
| || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_MEMSET_CHKP) |
| { |
| tree dst = gimple_call_arg (stmt, 0); |
| tree dst_bnd = gimple_call_arg (stmt, 1); |
| bool is_memset = DECL_FUNCTION_CODE (fndecl) == BUILT_IN_MEMSET_CHKP; |
| tree size = gimple_call_arg (stmt, is_memset ? 3 : 4); |
| tree fndecl_nochk; |
| gimple_stmt_iterator j; |
| basic_block check_bb; |
| address_t size_val; |
| int sign; |
| bool known; |
| |
| /* We may replace call with corresponding __chkp_*_nobnd |
| call in case destination pointer base type is not |
| void or pointer. */ |
| if (POINTER_TYPE_P (TREE_TYPE (dst)) |
| && !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (dst))) |
| && !chkp_type_has_pointer (TREE_TYPE (TREE_TYPE (dst)))) |
| { |
| tree fndecl_nobnd |
| = chkp_get_nobnd_fndecl (DECL_FUNCTION_CODE (fndecl)); |
| |
| if (fndecl_nobnd) |
| fndecl = fndecl_nobnd; |
| } |
| |
| fndecl_nochk = chkp_get_nochk_fndecl (DECL_FUNCTION_CODE (fndecl)); |
| |
| if (fndecl_nochk) |
| fndecl = fndecl_nochk; |
| |
| if (fndecl != gimple_call_fndecl (stmt)) |
| { |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| { |
| fprintf (dump_file, "Replacing call: "); |
| print_gimple_stmt (dump_file, stmt, 0, |
| TDF_VOPS|TDF_MEMSYMS); |
| } |
| |
| gimple_call_set_fndecl (stmt, fndecl); |
| |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| { |
| fprintf (dump_file, "With a new call: "); |
| print_gimple_stmt (dump_file, stmt, 0, |
| TDF_VOPS|TDF_MEMSYMS); |
| } |
| } |
| |
| /* If there is no nochk version of function then |
| do nothing. Otherwise insert checks before |
| the call. */ |
| if (!fndecl_nochk) |
| continue; |
| |
| /* If size passed to call is known and > 0 |
| then we may insert checks unconditionally. */ |
| size_val.pol.create (0); |
| chkp_collect_value (size, size_val); |
| known = chkp_is_constant_addr (size_val, &sign); |
| size_val.pol.release (); |
| |
| /* If we are not sure size is not zero then we have |
| to perform runtime check for size and perform |
| checks only when size is not zero. */ |
| if (!known) |
| { |
| gimple *check = gimple_build_cond (NE_EXPR, |
| size, |
| size_zero_node, |
| NULL_TREE, |
| NULL_TREE); |
| |
| /* Split block before string function call. */ |
| gsi_prev (&i); |
| check_bb = insert_cond_bb (bb, gsi_stmt (i), check, |
| profile_probability::likely ()); |
| |
| /* Set position for checks. */ |
| j = gsi_last_bb (check_bb); |
| |
| /* The block was splitted and therefore we |
| need to set iterator to its end. */ |
| i = gsi_last_bb (bb); |
| } |
| /* If size is known to be zero then no checks |
| should be performed. */ |
| else if (!sign) |
| continue; |
| else |
| j = i; |
| |
| size = size_binop (MINUS_EXPR, size, size_one_node); |
| if (!is_memset) |
| { |
| tree src = gimple_call_arg (stmt, 2); |
| tree src_bnd = gimple_call_arg (stmt, 3); |
| |
| chkp_check_mem_access (src, fold_build_pointer_plus (src, size), |
| src_bnd, j, gimple_location (stmt), |
| integer_zero_node); |
| } |
| |
| chkp_check_mem_access (dst, fold_build_pointer_plus (dst, size), |
| dst_bnd, j, gimple_location (stmt), |
| integer_one_node); |
| |
| } |
| } |
| } |
| } |
| |
| /* Intrumentation pass inserts most of bounds creation code |
| in the header of the function. We want to move bounds |
| creation closer to bounds usage to reduce bounds lifetime. |
| We also try to avoid bounds creation code on paths where |
| bounds are not used. */ |
| static void |
| chkp_reduce_bounds_lifetime (void) |
| { |
| basic_block bb = FALLTHRU_EDGE (ENTRY_BLOCK_PTR_FOR_FN (cfun))->dest; |
| gimple_stmt_iterator i; |
| |
| for (i = gsi_start_bb (bb); !gsi_end_p (i); ) |
| { |
| gimple *dom_use, *use_stmt, *stmt = gsi_stmt (i); |
| basic_block dom_bb; |
| ssa_op_iter iter; |
| imm_use_iterator use_iter; |
| use_operand_p use_p; |
| tree op; |
| bool want_move = false; |
| bool deps = false; |
| |
| if (gimple_code (stmt) == GIMPLE_CALL |
| && gimple_call_fndecl (stmt) == chkp_bndmk_fndecl) |
| want_move = true; |
| |
| if (gimple_code (stmt) == GIMPLE_ASSIGN |
| && POINTER_BOUNDS_P (gimple_assign_lhs (stmt)) |
| && gimple_assign_rhs_code (stmt) == VAR_DECL) |
| want_move = true; |
| |
| if (!want_move) |
| { |
| gsi_next (&i); |
| continue; |
| } |
| |
| /* Check we do not increase other values lifetime. */ |
| FOR_EACH_PHI_OR_STMT_USE (use_p, stmt, iter, SSA_OP_USE) |
| { |
| op = USE_FROM_PTR (use_p); |
| |
| if (TREE_CODE (op) == SSA_NAME |
| && gimple_code (SSA_NAME_DEF_STMT (op)) != GIMPLE_NOP) |
| { |
| deps = true; |
| break; |
| } |
| } |
| |
| if (deps) |
| { |
| gsi_next (&i); |
| continue; |
| } |
| |
| /* Check all usages of bounds. */ |
| if (gimple_code (stmt) == GIMPLE_CALL) |
| op = gimple_call_lhs (stmt); |
| else |
| { |
| gcc_assert (gimple_code (stmt) == GIMPLE_ASSIGN); |
| op = gimple_assign_lhs (stmt); |
| } |
| |
| dom_use = NULL; |
| dom_bb = NULL; |
| |
| FOR_EACH_IMM_USE_STMT (use_stmt, use_iter, op) |
| { |
| if (is_gimple_debug (use_stmt)) |
| continue; |
| |
| if (dom_bb && |
| dominated_by_p (CDI_DOMINATORS, |
| dom_bb, gimple_bb (use_stmt))) |
| { |
| dom_use = use_stmt; |
| dom_bb = NULL; |
| } |
| else if (dom_bb) |
| dom_bb = nearest_common_dominator (CDI_DOMINATORS, dom_bb, |
| gimple_bb (use_stmt)); |
| else if (!dom_use) |
| dom_use = use_stmt; |
| else if (stmt_dominates_stmt_p (use_stmt, dom_use)) |
| dom_use = use_stmt; |
| else if (!stmt_dominates_stmt_p (dom_use, use_stmt) |
| /* If dom_use and use_stmt are PHI nodes in one BB |
| then it is OK to keep any of them as dom_use. |
| stmt_dominates_stmt_p returns 0 for such |
| combination, so check it here manually. */ |
| && (gimple_code (dom_use) != GIMPLE_PHI |
| || gimple_code (use_stmt) != GIMPLE_PHI |
| || gimple_bb (use_stmt) != gimple_bb (dom_use)) |
| ) |
| { |
| dom_bb = nearest_common_dominator (CDI_DOMINATORS, |
| gimple_bb (use_stmt), |
| gimple_bb (dom_use)); |
| dom_use = NULL; |
| } |
| } |
| |
| /* In case there is a single use, just move bounds |
| creation to the use. */ |
| if (dom_use || dom_bb) |
| { |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| { |
| fprintf (dump_file, "Moving creation of "); |
| print_generic_expr (dump_file, op); |
| fprintf (dump_file, " down to its use.\n"); |
| } |
| |
| if (dom_use && gimple_code (dom_use) == GIMPLE_PHI) |
| { |
| dom_bb = get_immediate_dominator (CDI_DOMINATORS, |
| gimple_bb (dom_use)); |
| dom_use = NULL; |
| } |
| |
| if (dom_bb == bb |
| || (dom_use && gimple_bb (dom_use) == bb)) |
| { |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, "Cannot move statement bacause there is no " |
| "suitable dominator block other than entry block.\n"); |
| |
| gsi_next (&i); |
| } |
| else |
| { |
| if (dom_bb) |
| { |
| gimple_stmt_iterator last = gsi_last_bb (dom_bb); |
| if (!gsi_end_p (last) && stmt_ends_bb_p (gsi_stmt (last))) |
| gsi_move_before (&i, &last); |
| else |
| gsi_move_after (&i, &last); |
| } |
| else |
| { |
| gimple_stmt_iterator gsi = gsi_for_stmt (dom_use); |
| gsi_move_before (&i, &gsi); |
| } |
| |
| gimple_set_vdef (stmt, NULL_TREE); |
| gimple_set_vuse (stmt, NULL_TREE); |
| update_stmt (stmt); |
| } |
| } |
| else |
| gsi_next (&i); |
| } |
| } |
| |
| /* Initilize checker optimization pass. */ |
| static void |
| chkp_opt_init (void) |
| { |
| check_infos.create (0); |
| |
| calculate_dominance_info (CDI_DOMINATORS); |
| calculate_dominance_info (CDI_POST_DOMINATORS); |
| |
| /* With LTO constant bounds vars may be not initialized by now. |
| Get constant bounds vars to handle their assignments during |
| optimizations. */ |
| chkp_get_zero_bounds_var (); |
| chkp_get_none_bounds_var (); |
| } |
| |
| /* Finalise checker optimization pass. */ |
| static void |
| chkp_opt_fini (void) |
| { |
| chkp_fix_cfg (); |
| |
| free_dominance_info (CDI_POST_DOMINATORS); |
| } |
| |
| /* Checker optimization pass function. */ |
| static unsigned int |
| chkp_opt_execute (void) |
| { |
| chkp_opt_init(); |
| |
| /* This optimization may introduce new checks |
| and thus we put it before checks search. */ |
| chkp_optimize_string_function_calls (); |
| |
| chkp_gather_checks_info (); |
| |
| chkp_remove_excess_intersections (); |
| |
| chkp_remove_constant_checks (); |
| |
| chkp_reduce_bounds_lifetime (); |
| |
| chkp_release_check_info (); |
| |
| chkp_opt_fini (); |
| |
| return 0; |
| } |
| |
| /* Pass gate. */ |
| static bool |
| chkp_opt_gate (void) |
| { |
| return chkp_function_instrumented_p (cfun->decl) |
| && (flag_chkp_optimize > 0 |
| || (flag_chkp_optimize == -1 && optimize > 0)); |
| } |
| |
| namespace { |
| |
| const pass_data pass_data_chkp_opt = |
| { |
| GIMPLE_PASS, /* type */ |
| "chkpopt", /* name */ |
| OPTGROUP_NONE, /* optinfo_flags */ |
| TV_NONE, /* tv_id */ |
| PROP_ssa | PROP_cfg, /* properties_required */ |
| 0, /* properties_provided */ |
| 0, /* properties_destroyed */ |
| 0, /* todo_flags_start */ |
| TODO_verify_il |
| | TODO_update_ssa /* todo_flags_finish */ |
| }; |
| |
| class pass_chkp_opt : public gimple_opt_pass |
| { |
| public: |
| pass_chkp_opt (gcc::context *ctxt) |
| : gimple_opt_pass (pass_data_chkp_opt, ctxt) |
| {} |
| |
| /* opt_pass methods: */ |
| virtual opt_pass * clone () |
| { |
| return new pass_chkp_opt (m_ctxt); |
| } |
| |
| virtual bool gate (function *) |
| { |
| return chkp_opt_gate (); |
| } |
| |
| virtual unsigned int execute (function *) |
| { |
| return chkp_opt_execute (); |
| } |
| |
| }; // class pass_chkp_opt |
| |
| } // anon namespace |
| |
| gimple_opt_pass * |
| make_pass_chkp_opt (gcc::context *ctxt) |
| { |
| return new pass_chkp_opt (ctxt); |
| } |