diff options
Diffstat (limited to 'gcc/asan.c')
| -rw-r--r-- | gcc/asan.c | 51 |
1 files changed, 41 insertions, 10 deletions
diff --git a/gcc/asan.c b/gcc/asan.c index beb002374a2..339765523a8 100644 --- a/gcc/asan.c +++ b/gcc/asan.c @@ -1319,7 +1319,7 @@ asan_protect_global (tree decl) IS_STORE is either 1 (for a store) or 0 (for a load). */ static tree -report_error_func (bool is_store, HOST_WIDE_INT size_in_bytes) +report_error_func (bool is_store, HOST_WIDE_INT size_in_bytes, bool slow_p) { static enum built_in_function report[2][6] = { { BUILT_IN_ASAN_REPORT_LOAD1, BUILT_IN_ASAN_REPORT_LOAD2, @@ -1329,7 +1329,8 @@ report_error_func (bool is_store, HOST_WIDE_INT size_in_bytes) BUILT_IN_ASAN_REPORT_STORE4, BUILT_IN_ASAN_REPORT_STORE8, BUILT_IN_ASAN_REPORT_STORE16, BUILT_IN_ASAN_REPORT_STORE_N } }; if ((size_in_bytes & (size_in_bytes - 1)) != 0 - || size_in_bytes > 16) + || size_in_bytes > 16 + || slow_p) return builtin_decl_implicit (report[is_store][5]); return builtin_decl_implicit (report[is_store][exact_log2 (size_in_bytes)]); } @@ -1508,7 +1509,8 @@ build_shadow_mem_access (gimple_stmt_iterator *gsi, location_t location, static void build_check_stmt (location_t location, tree base, gimple_stmt_iterator *iter, - bool before_p, bool is_store, HOST_WIDE_INT size_in_bytes) + bool before_p, bool is_store, HOST_WIDE_INT size_in_bytes, + bool slow_p = false) { gimple_stmt_iterator gsi; basic_block then_bb, else_bb; @@ -1522,9 +1524,15 @@ build_check_stmt (location_t location, tree base, gimple_stmt_iterator *iter, HOST_WIDE_INT real_size_in_bytes = size_in_bytes; tree sz_arg = NULL_TREE; - if ((size_in_bytes & (size_in_bytes - 1)) != 0 - || size_in_bytes > 16) - real_size_in_bytes = 1; + if (size_in_bytes == 1) + slow_p = false; + else if ((size_in_bytes & (size_in_bytes - 1)) != 0 + || size_in_bytes > 16 + || slow_p) + { + real_size_in_bytes = 1; + slow_p = true; + } /* Get an iterator on the point where we can add the condition statement for the instrumentation. */ @@ -1582,8 +1590,8 @@ build_check_stmt (location_t location, tree base, gimple_stmt_iterator *iter, t = gimple_assign_lhs (gimple_seq_last (seq)); gimple_seq_set_location (seq, location); gsi_insert_seq_after (&gsi, seq, GSI_CONTINUE_LINKING); - /* For weird access sizes, check first and last byte. */ - if (real_size_in_bytes != size_in_bytes) + /* For weird access sizes or misaligned, check first and last byte. */ + if (slow_p) { g = gimple_build_assign_with_ops (PLUS_EXPR, make_ssa_name (uintptr_type, NULL), @@ -1626,7 +1634,7 @@ build_check_stmt (location_t location, tree base, gimple_stmt_iterator *iter, /* Generate call to the run-time library (e.g. __asan_report_load8). */ gsi = gsi_start_bb (then_bb); - g = gimple_build_call (report_error_func (is_store, size_in_bytes), + g = gimple_build_call (report_error_func (is_store, size_in_bytes, slow_p), sz_arg ? 2 : 1, base_addr, sz_arg); gimple_set_location (g, location); gsi_insert_after (&gsi, g, GSI_NEW_STMT); @@ -1722,8 +1730,31 @@ instrument_derefs (gimple_stmt_iterator *iter, tree t, base = build_fold_addr_expr (t); if (!has_mem_ref_been_instrumented (base, size_in_bytes)) { + bool slow_p = false; + if (size_in_bytes > 1) + { + if ((size_in_bytes & (size_in_bytes - 1)) != 0 + || size_in_bytes > 16) + slow_p = true; + else + { + unsigned int align = get_object_alignment (t); + if (align < size_in_bytes * BITS_PER_UNIT) + { + /* On non-strict alignment targets, if + 16-byte access is just 8-byte aligned, + this will result in misaligned shadow + memory 2 byte load, but otherwise can + be handled using one read. */ + if (size_in_bytes != 16 + || STRICT_ALIGNMENT + || align < 8 * BITS_PER_UNIT) + slow_p = true; + } + } + } build_check_stmt (location, base, iter, /*before_p=*/true, - is_store, size_in_bytes); + is_store, size_in_bytes, slow_p); update_mem_ref_hash_table (base, size_in_bytes); update_mem_ref_hash_table (t, size_in_bytes); } |