Florian Schneider
bac82e2592
Instead of calling code object directly, call indirectly and pass the code object in a register. The object pool is then loaded from the code object. This is another preparation step for making generated code relocatable. All non-ia32 platforms: No entry patching. ARM: PC marker (now code object) moves to the same place as on x64 (below saved PP, above saved FP). R9 is now used as PP, R10 as CODE_REG. BUG= R=koda@google.com, rmacnak@google.com Committed: https://github.com/dart-lang/sdk/commit/1d343e5a7b75168fb6c9f86b64c55173cdbdc9b2 Review URL: https://codereview.chromium.org//1192103004 .
60 lines
1.9 KiB
C++
60 lines
1.9 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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bool status = VirtualMemory::Protect(reinterpret_cast<void*>(address),
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size,
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VirtualMemory::kReadWrite);
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ASSERT(status);
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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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bool status = VirtualMemory::Protect(reinterpret_cast<void*>(address_),
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size_,
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VirtualMemory::kReadExecute);
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ASSERT(status);
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}
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}
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// The patch code buffer contains the jmp code which will be inserted at
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// entry point.
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void CodePatcher::PatchEntry(const Code& code, const Code& new_code) {
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ASSERT(code.instructions() == code.active_instructions());
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code.set_active_instructions(new_code.instructions());
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}
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// The entry point is a jmp instruction, the patch code buffer contains
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// original code, the entry point contains the jump instruction.
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void CodePatcher::RestoreEntry(const Code& code) {
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if (!IsEntryPatched(code)) return;
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ASSERT(code.instructions() != code.active_instructions());
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code.set_active_instructions(code.instructions());
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}
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bool CodePatcher::IsEntryPatched(const Code& code) {
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return code.instructions() != code.active_instructions();
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}
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} // namespace dart
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