Régis Crelier
0491d5cde7
This reverts commit 44186dfdcd.
Reason for revert: not working on vm-kernel-precomp-android-release-arm
Original change's description:
> [VM runtime] Dual mapping of executable pages.
>
> Change-Id: Iaad78d324e25462ce951f4df26974a6a368c50b7
> Reviewed-on: https://dart-review.googlesource.com/c/93377
> Commit-Queue: Régis Crelier <regis@google.com>
> Reviewed-by: Ryan Macnak <rmacnak@google.com>
TBR=rmacnak@google.com,regis@google.com
Change-Id: I793ceee6252111eafbcbfe6e28268f4f6f2d7215
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://dart-review.googlesource.com/c/94989
Reviewed-by: Régis Crelier <regis@google.com>
Commit-Queue: Régis Crelier <regis@google.com>
51 lines
1.7 KiB
C++
51 lines
1.7 KiB
C++
// Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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#include "vm/code_patcher.h"
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#include "vm/cpu.h"
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#include "vm/instructions.h"
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#include "vm/object.h"
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#include "vm/virtual_memory.h"
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namespace dart {
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DEFINE_FLAG(bool, write_protect_code, true, "Write protect jitted code");
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WritableInstructionsScope::WritableInstructionsScope(uword address,
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intptr_t size)
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: address_(address), size_(size) {
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if (FLAG_write_protect_code) {
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VirtualMemory::Protect(reinterpret_cast<void*>(address), size,
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VirtualMemory::kReadWrite);
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}
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}
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WritableInstructionsScope::~WritableInstructionsScope() {
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if (FLAG_write_protect_code) {
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VirtualMemory::Protect(reinterpret_cast<void*>(address_), size_,
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VirtualMemory::kReadExecute);
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}
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}
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bool MatchesPattern(uword end, const int16_t* pattern, intptr_t size) {
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// When breaking within generated code in GDB, it may overwrite individual
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// instructions with trap instructions, which can cause this test to fail.
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//
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// Ignoring trap instructions would work well enough within GDB alone, but it
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// doesn't work in RR, because the check for the trap instrution itself will
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// cause replay to diverge from the original record.
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if (FLAG_support_rr) return true;
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uint8_t* bytes = reinterpret_cast<uint8_t*>(end - size);
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for (intptr_t i = 0; i < size; i++) {
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int16_t val = pattern[i];
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if ((val >= 0) && (val != bytes[i])) {
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return false;
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}
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}
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return true;
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}
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} // namespace dart
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