1 | // Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file |
2 | // for details. All rights reserved. Use of this source code is governed by a |
3 | // BSD-style license that can be found in the LICENSE file. |
4 | |
5 | #include "vm/code_patcher.h" |
6 | #include "vm/cpu.h" |
7 | #include "vm/instructions.h" |
8 | #include "vm/object.h" |
9 | #include "vm/virtual_memory.h" |
10 | |
11 | namespace dart { |
12 | |
13 | DEFINE_FLAG(bool, write_protect_code, true, "Write protect jitted code" ); |
14 | |
15 | #if defined(DUAL_MAPPING_SUPPORTED) |
16 | DEFINE_FLAG(bool, dual_map_code, true, "Dual map jitted code, RW and RX" ); |
17 | #else |
18 | DEFINE_FLAG(bool, dual_map_code, false, "Dual map jitted code, RW and RX" ); |
19 | #endif // defined(DUAL_MAPPING_SUPPORTED) |
20 | |
21 | #if defined(TARGET_ARCH_IA32) |
22 | WritableInstructionsScope::WritableInstructionsScope(uword address, |
23 | intptr_t size) |
24 | : address_(address), size_(size) { |
25 | if (FLAG_write_protect_code) { |
26 | VirtualMemory::Protect(reinterpret_cast<void*>(address), size, |
27 | VirtualMemory::kReadWrite); |
28 | } |
29 | } |
30 | |
31 | WritableInstructionsScope::~WritableInstructionsScope() { |
32 | if (FLAG_write_protect_code) { |
33 | VirtualMemory::Protect(reinterpret_cast<void*>(address_), size_, |
34 | VirtualMemory::kReadExecute); |
35 | } |
36 | } |
37 | #endif // defined(TARGET_ARCH_IA32) |
38 | |
39 | bool MatchesPattern(uword end, const int16_t* pattern, intptr_t size) { |
40 | // When breaking within generated code in GDB, it may overwrite individual |
41 | // instructions with trap instructions, which can cause this test to fail. |
42 | // |
43 | // Ignoring trap instructions would work well enough within GDB alone, but it |
44 | // doesn't work in RR, because the check for the trap instrution itself will |
45 | // cause replay to diverge from the original record. |
46 | if (FLAG_support_rr) return true; |
47 | |
48 | uint8_t* bytes = reinterpret_cast<uint8_t*>(end - size); |
49 | for (intptr_t i = 0; i < size; i++) { |
50 | int16_t val = pattern[i]; |
51 | if ((val >= 0) && (val != bytes[i])) { |
52 | return false; |
53 | } |
54 | } |
55 | return true; |
56 | } |
57 | |
58 | } // namespace dart |
59 | |