Eric Seidel
1cb6dd08ea
Closes https://github.com/dart-lang/sdk/pull/60242 GitOrigin-RevId: da68fe5ee69099dea6441c13308359ae44f9fcaf Change-Id: I5cc63034af05a0673da51c6b939c9b626f3a0c24 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/413241 Commit-Queue: Slava Egorov <vegorov@google.com> Reviewed-by: Slava Egorov <vegorov@google.com>
66 lines
2.3 KiB
C++
66 lines
2.3 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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#if defined(DART_HOST_OS_MACOS) || defined(DART_HOST_OS_MACOS_IOS)
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// On iOS even with debugger attached we must still guarantee that memory
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// is never executable and writable at the same time. On Mac OS X
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// com.apple.security.cs.allow-jit entitlement allows WX memory regions to be
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// created - but we should not rely on this entitlement to be present.
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static constexpr bool kShouldWriteProtectCodeByDefault = true;
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#else
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static constexpr bool kShouldWriteProtectCodeByDefault = false;
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#endif
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DEFINE_FLAG(bool,
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write_protect_code,
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kShouldWriteProtectCodeByDefault,
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"Write protect jitted code");
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#if defined(TARGET_ARCH_IA32)
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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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#endif // defined(TARGET_ARCH_IA32)
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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 instruction 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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