Create the framework for adding a thumb2 backend for ARM. So far, it...

src/arm/assembler-thumb2-inl.h

Index: src/arm/assembler-thumb2-inl.h
===================================================================
--- src/arm/assembler-thumb2-inl.h	(revision 0)
+++ src/arm/assembler-thumb2-inl.h	(revision 0)
@@ -0,0 +1,268 @@
+// Copyright (c) 1994-2006 Sun Microsystems Inc.
+// All Rights Reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions
+// are met:
+//
+// - Redistributions of source code must retain the above copyright notice,
+// this list of conditions and the following disclaimer.
+//
+// - Redistribution in binary form must reproduce the above copyright
+// notice, this list of conditions and the following disclaimer in the
+// documentation and/or other materials provided with the
+// distribution.
+//
+// - Neither the name of Sun Microsystems or the names of contributors may
+// be used to endorse or promote products derived from this software without
+// specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+// FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+// COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+// OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// The original source code covered by the above license above has been modified
+// significantly by Google Inc.
+// Copyright 2006-2008 the V8 project authors. All rights reserved.
+
+#ifndef V8_ARM_ASSEMBLER_THUMB2_INL_H_
+#define V8_ARM_ASSEMBLER_THUMB2_INL_H_
+
+#include "arm/assembler-thumb2.h"
+#include "cpu.h"
+
+
+namespace v8 {
+namespace internal {
+
+Condition NegateCondition(Condition cc) {
+  ASSERT(cc != al);
+  return static_cast<Condition>(cc ^ ne);
+}
+
+
+void RelocInfo::apply(intptr_t delta) {
+  if (RelocInfo::IsInternalReference(rmode_)) {
+    // absolute code pointer inside code object moves with the code object.
+    int32_t* p = reinterpret_cast<int32_t*>(pc_);
+    *p += delta;  // relocate entry
+  }
+  // We do not use pc relative addressing on ARM, so there is
+  // nothing else to do.
+}
+
+
+Address RelocInfo::target_address() {
+  ASSERT(IsCodeTarget(rmode_) || rmode_ == RUNTIME_ENTRY);
+  return Assembler::target_address_at(pc_);
+}
+
+
+Address RelocInfo::target_address_address() {
+  ASSERT(IsCodeTarget(rmode_) || rmode_ == RUNTIME_ENTRY);
+  return reinterpret_cast<Address>(Assembler::target_address_address_at(pc_));
+}
+
+
+void RelocInfo::set_target_address(Address target) {
+  ASSERT(IsCodeTarget(rmode_) || rmode_ == RUNTIME_ENTRY);
+  Assembler::set_target_address_at(pc_, target);
+}
+
+
+Object* RelocInfo::target_object() {
+  ASSERT(IsCodeTarget(rmode_) || rmode_ == EMBEDDED_OBJECT);
+  return Memory::Object_at(Assembler::target_address_address_at(pc_));
+}
+
+
+Handle<Object> RelocInfo::target_object_handle(Assembler* origin) {
+  ASSERT(IsCodeTarget(rmode_) || rmode_ == EMBEDDED_OBJECT);
+  return Memory::Object_Handle_at(Assembler::target_address_address_at(pc_));
+}
+
+
+Object** RelocInfo::target_object_address() {
+  ASSERT(IsCodeTarget(rmode_) || rmode_ == EMBEDDED_OBJECT);
+  return reinterpret_cast<Object**>(Assembler::target_address_address_at(pc_));
+}
+
+
+void RelocInfo::set_target_object(Object* target) {
+  ASSERT(IsCodeTarget(rmode_) || rmode_ == EMBEDDED_OBJECT);
+  Assembler::set_target_address_at(pc_, reinterpret_cast<Address>(target));
+}
+
+
+Address* RelocInfo::target_reference_address() {
+  ASSERT(rmode_ == EXTERNAL_REFERENCE);
+  return reinterpret_cast<Address*>(Assembler::target_address_address_at(pc_));
+}
+
+
+Address RelocInfo::call_address() {
+  ASSERT(IsPatchedReturnSequence());
+  // The 2 instructions offset assumes patched return sequence.
+  ASSERT(IsJSReturn(rmode()));
+  return Memory::Address_at(pc_ + 2 * Assembler::kInstrSize);
+}
+
+
+void RelocInfo::set_call_address(Address target) {
+  ASSERT(IsPatchedReturnSequence());
+  // The 2 instructions offset assumes patched return sequence.
+  ASSERT(IsJSReturn(rmode()));
+  Memory::Address_at(pc_ + 2 * Assembler::kInstrSize) = target;
+}
+
+
+Object* RelocInfo::call_object() {
+  return *call_object_address();
+}
+
+
+Object** RelocInfo::call_object_address() {
+  ASSERT(IsPatchedReturnSequence());
+  // The 2 instructions offset assumes patched return sequence.
+  ASSERT(IsJSReturn(rmode()));
+  return reinterpret_cast<Object**>(pc_ + 2 * Assembler::kInstrSize);
+}
+
+
+void RelocInfo::set_call_object(Object* target) {
+  *call_object_address() = target;
+}
+
+
+bool RelocInfo::IsPatchedReturnSequence() {
+  // On ARM a "call instruction" is actually two instructions.
+  //   mov lr, pc
+  //   ldr pc, [pc, #XXX]
+  return (Assembler::instr_at(pc_) == kMovLrPc)
+          && ((Assembler::instr_at(pc_ + Assembler::kInstrSize) & kLdrPCPattern)
+              == kLdrPCPattern);
+}
+
+
+Operand::Operand(int32_t immediate, RelocInfo::Mode rmode)  {
+  rm_ = no_reg;
+  imm32_ = immediate;
+  rmode_ = rmode;
+}
+
+
+Operand::Operand(const char* s) {
+  rm_ = no_reg;
+  imm32_ = reinterpret_cast<int32_t>(s);
+  rmode_ = RelocInfo::EMBEDDED_STRING;
+}
+
+
+Operand::Operand(const ExternalReference& f)  {
+  rm_ = no_reg;
+  imm32_ = reinterpret_cast<int32_t>(f.address());
+  rmode_ = RelocInfo::EXTERNAL_REFERENCE;
+}
+
+
+Operand::Operand(Object** opp) {
+  rm_ = no_reg;
+  imm32_ = reinterpret_cast<int32_t>(opp);
+  rmode_ = RelocInfo::NONE;
+}
+
+
+Operand::Operand(Context** cpp) {
+  rm_ = no_reg;
+  imm32_ = reinterpret_cast<int32_t>(cpp);
+  rmode_ = RelocInfo::NONE;
+}
+
+
+Operand::Operand(Smi* value) {
+  rm_ = no_reg;
+  imm32_ =  reinterpret_cast<intptr_t>(value);
+  rmode_ = RelocInfo::NONE;
+}
+
+
+Operand::Operand(Register rm) {
+  rm_ = rm;
+  rs_ = no_reg;
+  shift_op_ = LSL;
+  shift_imm_ = 0;
+}
+
+
+bool Operand::is_reg() const {
+  return rm_.is_valid() &&
+         rs_.is(no_reg) &&
+         shift_op_ == LSL &&
+         shift_imm_ == 0;
+}
+
+
+void Assembler::CheckBuffer() {
+  if (buffer_space() <= kGap) {
+    GrowBuffer();
+  }
+  if (pc_offset() >= next_buffer_check_) {
+    CheckConstPool(false, true);
+  }
+}
+
+
+void Assembler::emit(Instr x) {
+  CheckBuffer();
+  *reinterpret_cast<Instr*>(pc_) = x;
+  pc_ += kInstrSize;
+}
+
+
+Address Assembler::target_address_address_at(Address pc) {
+  Instr instr = Memory::int32_at(pc);
+  // Verify that the instruction at pc is a ldr<cond> <Rd>, [pc +/- offset_12].
+  ASSERT((instr & 0x0f7f0000) == 0x051f0000);
+  int offset = instr & 0xfff;  // offset_12 is unsigned
+  if ((instr & (1 << 23)) == 0) offset = -offset;  // U bit defines offset sign
+  // Verify that the constant pool comes after the instruction referencing it.
+  ASSERT(offset >= -4);
+  return pc + offset + 8;
+}
+
+
+Address Assembler::target_address_at(Address pc) {
+  return Memory::Address_at(target_address_address_at(pc));
+}
+
+
+void Assembler::set_target_at(Address constant_pool_entry,
+                              Address target) {
+  Memory::Address_at(constant_pool_entry) = target;
+}
+
+
+void Assembler::set_target_address_at(Address pc, Address target) {
+  Memory::Address_at(target_address_address_at(pc)) = target;
+  // Intuitively, we would think it is necessary to flush the instruction cache
+  // after patching a target address in the code as follows:
+  //   CPU::FlushICache(pc, sizeof(target));
+  // However, on ARM, no instruction was actually patched by the assignment
+  // above; the target address is not part of an instruction, it is patched in
+  // the constant pool and is read via a data access; the instruction accessing
+  // this address in the constant pool remains unchanged.
+}
+
+} }  // namespace v8::internal
+
+#endif  // V8_ARM_ASSEMBLER_THUMB2_INL_H_
+