| // Copyright (c) 2018, the Dart project authors. Please see the AUTHORS file |
| // for details. All rights reserved. Use of this source code is governed by a |
| // BSD-style license that can be found in the LICENSE file. |
| |
| #include "vm/reverse_pc_lookup_cache.h" |
| |
| #include "vm/isolate.h" |
| #include "vm/object.h" |
| #include "vm/object_store.h" |
| |
| namespace dart { |
| |
| CodePtr ReversePc::Lookup(IsolateGroup* group, |
| uword pc, |
| bool is_return_address) { |
| #if defined(DART_PRECOMPILED_RUNTIME) |
| // This can run in the middle of GC and must not allocate handles. |
| NoSafepointScope no_safepoint; |
| |
| if (is_return_address) { |
| pc--; |
| } |
| |
| // This expected number of tables is low, so we go through them linearly. If |
| // this changes, would could sort the table list during deserialization and |
| // binary search for the table. |
| GrowableObjectArrayPtr tables = group->object_store()->code_order_tables(); |
| intptr_t tables_length = Smi::Value(tables->ptr()->length_); |
| for (intptr_t i = 0; i < tables_length; i++) { |
| ArrayPtr table = |
| static_cast<ArrayPtr>(tables->ptr()->data_->ptr()->data()[i]); |
| intptr_t lo = 0; |
| intptr_t hi = Smi::Value(table->ptr()->length_) - 1; |
| |
| // Fast check if pc belongs to this table. |
| if (lo > hi) { |
| continue; |
| } |
| CodePtr first = static_cast<CodePtr>(table->ptr()->data()[lo]); |
| if (pc < Code::PayloadStartOf(first)) { |
| continue; |
| } |
| CodePtr last = static_cast<CodePtr>(table->ptr()->data()[hi]); |
| if (pc >= (Code::PayloadStartOf(last) + Code::PayloadSizeOf(last))) { |
| continue; |
| } |
| |
| // Binary search within the table for the matching Code. |
| while (lo <= hi) { |
| intptr_t mid = (hi - lo + 1) / 2 + lo; |
| ASSERT(mid >= lo); |
| ASSERT(mid <= hi); |
| CodePtr code = static_cast<CodePtr>(table->ptr()->data()[mid]); |
| uword code_start = Code::PayloadStartOf(code); |
| uword code_end = code_start + Code::PayloadSizeOf(code); |
| if (pc < code_start) { |
| hi = mid - 1; |
| } else if (pc >= code_end) { |
| lo = mid + 1; |
| } else { |
| return code; |
| } |
| } |
| } |
| #endif // defined(DART_PRECOMPILED_RUNTIME) |
| |
| return Code::null(); |
| } |
| |
| } // namespace dart |