Add support for Embedded Constant Pools for PPC and Arm

src/ppc/assembler-ppc-inl.h

Index: src/ppc/assembler-ppc-inl.h
diff --git a/src/ppc/assembler-ppc-inl.h b/src/ppc/assembler-ppc-inl.h
index d95c7ec5968a5e8fec471bdabed8f6dcf84d01d4..14b5503a17349a7cde1d9efd9e74525121b8df4e 100644
--- a/src/ppc/assembler-ppc-inl.h
+++ b/src/ppc/assembler-ppc-inl.h
@@ -94,6 +94,13 @@ Address RelocInfo::target_address_address() {
   DCHECK(IsCodeTarget(rmode_) || IsRuntimeEntry(rmode_) ||
          rmode_ == EMBEDDED_OBJECT || rmode_ == EXTERNAL_REFERENCE);
 
+  if (FLAG_enable_embedded_constant_pool &&
+      Assembler::IsConstantPoolLoadStart(pc_)) {
+    // We return the PC for ool constant pool since this function is used by the
+    // serializer and expects the address to reside within the code object.
+    return reinterpret_cast<Address>(pc_);
+  }
+
   // Read the address of the word containing the target_address in an
   // instruction stream.
   // The only architecture-independent user of this function is the serializer.
@@ -108,6 +115,14 @@ Address RelocInfo::target_address_address() {
 
 
 Address RelocInfo::constant_pool_entry_address() {
+  if (FLAG_enable_embedded_constant_pool) {
+    Address constant_pool = host_->constant_pool();
+    DCHECK(constant_pool);
+    ConstantPoolEntry::Access access;
+    if (Assembler::IsConstantPoolLoadStart(pc_, &access))
+      return Assembler::target_constant_pool_address_at(
+          pc_, constant_pool, access, ConstantPoolEntry::INTPTR);
+  }
   UNREACHABLE();
   return NULL;
 }
@@ -143,12 +158,28 @@ Address Assembler::target_address_from_return_address(Address pc) {
 //  mtlr  ip
 //  blrl
 //                      @ return address
-  return pc - (kMovInstructions + 2) * kInstrSize;
+  int len;
+  ConstantPoolEntry::Access access;
+  if (FLAG_enable_embedded_constant_pool &&
+      IsConstantPoolLoadEnd(pc - 3 * kInstrSize, &access)) {
+    len = (access == ConstantPoolEntry::OVERFLOWED) ? 2 : 1;
+  } else {
+    len = kMovInstructionsNoConstantPool;
+  }
+  return pc - (len + 2) * kInstrSize;
 }
 
 
 Address Assembler::return_address_from_call_start(Address pc) {
-  return pc + (kMovInstructions + 2) * kInstrSize;
+  int len;
+  ConstantPoolEntry::Access access;
+  if (FLAG_enable_embedded_constant_pool &&
+      IsConstantPoolLoadStart(pc, &access)) {
+    len = (access == ConstantPoolEntry::OVERFLOWED) ? 2 : 1;
+  } else {
+    len = kMovInstructionsNoConstantPool;
+  }
+  return pc + (len + 2) * kInstrSize;
 }
 
 
@@ -226,8 +257,10 @@ void RelocInfo::set_target_cell(Cell* cell, WriteBarrierMode write_barrier_mode,
 }
 
 
-static const int kNoCodeAgeInstructions = 6;
-static const int kCodeAgingInstructions = Assembler::kMovInstructions + 3;
+static const int kNoCodeAgeInstructions =
+    FLAG_enable_embedded_constant_pool ? 7 : 6;
+static const int kCodeAgingInstructions =
+    Assembler::kMovInstructionsNoConstantPool + 3;
 static const int kNoCodeAgeSequenceInstructions =
     ((kNoCodeAgeInstructions >= kCodeAgingInstructions)
          ? kNoCodeAgeInstructions
@@ -448,8 +481,14 @@ bool Operand::is_reg() const { return rm_.is_valid(); }
 
 
 // Fetch the 32bit value from the FIXED_SEQUENCE lis/ori
-Address Assembler::target_address_at(Address pc,
-                                     ConstantPoolArray* constant_pool) {
+Address Assembler::target_address_at(Address pc, Address constant_pool) {
+  if (FLAG_enable_embedded_constant_pool && constant_pool) {
+    ConstantPoolEntry::Access access;
+    if (IsConstantPoolLoadStart(pc, &access))
+      return Memory::Address_at(target_constant_pool_address_at(
+          pc, constant_pool, access, ConstantPoolEntry::INTPTR));
+  }
+
   Instr instr1 = instr_at(pc);
   Instr instr2 = instr_at(pc + kInstrSize);
   // Interpret 2 instructions generated by lis/ori
@@ -475,6 +514,127 @@ Address Assembler::target_address_at(Address pc,
 }
 
 
+#if V8_TARGET_ARCH_PPC64
+const int kLoadIntptrOpcode = LD;
+#else
+const int kLoadIntptrOpcode = LWZ;
+#endif
+
+// Constant pool load sequence detection:
+// 1) REGULAR access:
+//    load <dst>, kConstantPoolRegister + <offset>
+//
+// 2) OVERFLOWED access:
+//    addis <scratch>, kConstantPoolRegister, <offset_high>
+//    load <dst>, <scratch> + <offset_low>
+bool Assembler::IsConstantPoolLoadStart(Address pc,
+                                        ConstantPoolEntry::Access* access) {
+  Instr instr = instr_at(pc);
+  int opcode = instr & kOpcodeMask;
+  if (!GetRA(instr).is(kConstantPoolRegister)) return false;
+  bool overflowed = (opcode == ADDIS);
+#ifdef DEBUG
+  if (overflowed) {
+    opcode = instr_at(pc + kInstrSize) & kOpcodeMask;
+  }
+  DCHECK(opcode == kLoadIntptrOpcode || opcode == LFD);
+#endif
+  if (access) {
+    *access = (overflowed ? ConstantPoolEntry::OVERFLOWED
+                          : ConstantPoolEntry::REGULAR);
+  }
+  return true;
+}
+
+
+bool Assembler::IsConstantPoolLoadEnd(Address pc,
+                                      ConstantPoolEntry::Access* access) {
+  Instr instr = instr_at(pc);
+  int opcode = instr & kOpcodeMask;
+  bool overflowed = false;
+  if (!(opcode == kLoadIntptrOpcode || opcode == LFD)) return false;
+  if (!GetRA(instr).is(kConstantPoolRegister)) {
+    instr = instr_at(pc - kInstrSize);
+    opcode = instr & kOpcodeMask;
+    if ((opcode != ADDIS) || !GetRA(instr).is(kConstantPoolRegister)) {
+      return false;
+    }
+    overflowed = true;
+  }
+  if (access) {
+    *access = (overflowed ? ConstantPoolEntry::OVERFLOWED
+                          : ConstantPoolEntry::REGULAR);
+  }
+  return true;
+}
+
+
+int Assembler::GetConstantPoolOffset(Address pc,
+                                     ConstantPoolEntry::Access access,
+                                     ConstantPoolEntry::Type type) {
+  bool overflowed = (access == ConstantPoolEntry::OVERFLOWED);
+#ifdef DEBUG
+  ConstantPoolEntry::Access access_check =
+      static_cast<ConstantPoolEntry::Access>(-1);
+  DCHECK(IsConstantPoolLoadStart(pc, &access_check));
+  DCHECK(access_check == access);
+#endif
+  int offset;
+  if (overflowed) {
+    offset = (instr_at(pc) & kImm16Mask) << 16;
+    offset += SIGN_EXT_IMM16(instr_at(pc + kInstrSize) & kImm16Mask);
+    DCHECK(!is_int16(offset));
+  } else {
+    offset = SIGN_EXT_IMM16((instr_at(pc) & kImm16Mask));
+  }
+  return offset;
+}
+
+
+void Assembler::PatchConstantPoolAccessInstruction(
+    int pc_offset, int offset, ConstantPoolEntry::Access access,
+    ConstantPoolEntry::Type type) {
+  Address pc = buffer_ + pc_offset;
+  bool overflowed = (access == ConstantPoolEntry::OVERFLOWED);
+#ifdef DEBUG
+  ConstantPoolEntry::Access access_check =
+      static_cast<ConstantPoolEntry::Access>(-1);
+  DCHECK(IsConstantPoolLoadStart(pc, &access_check));
+  DCHECK(access_check == access);
+  DCHECK(overflowed != is_int16(offset));
+#endif
+  if (overflowed) {
+    int hi_word = static_cast<int>(offset >> 16);
+    int lo_word = static_cast<int>(offset & 0xffff);
+    if (lo_word & 0x8000) hi_word++;
+
+    Instr instr1 = instr_at(pc);
+    Instr instr2 = instr_at(pc + kInstrSize);
+    instr1 &= ~kImm16Mask;
+    instr1 |= (hi_word & kImm16Mask);
+    instr2 &= ~kImm16Mask;
+    instr2 |= (lo_word & kImm16Mask);
+    instr_at_put(pc, instr1);
+    instr_at_put(pc + kInstrSize, instr2);
+  } else {
+    Instr instr = instr_at(pc);
+    instr &= ~kImm16Mask;
+    instr |= (offset & kImm16Mask);
+    instr_at_put(pc, instr);
+  }
+}
+
+
+Address Assembler::target_constant_pool_address_at(
+    Address pc, Address constant_pool, ConstantPoolEntry::Access access,
+    ConstantPoolEntry::Type type) {
+  Address addr = constant_pool;
+  DCHECK(addr);
+  addr += GetConstantPoolOffset(pc, access, type);
+  return addr;
+}
+
+
 // This sets the branch destination (which gets loaded at the call address).
 // This is for calls and branches within generated code.  The serializer
 // has already deserialized the mov instructions etc.
@@ -497,10 +657,18 @@ void Assembler::deserialization_set_target_internal_reference_at(
 
 
 // This code assumes the FIXED_SEQUENCE of lis/ori
-void Assembler::set_target_address_at(Address pc,
-                                      ConstantPoolArray* constant_pool,
+void Assembler::set_target_address_at(Address pc, Address constant_pool,
                                       Address target,
                                       ICacheFlushMode icache_flush_mode) {
+  if (FLAG_enable_embedded_constant_pool && constant_pool) {
+    ConstantPoolEntry::Access access;
+    if (IsConstantPoolLoadStart(pc, &access)) {
+      Memory::Address_at(target_constant_pool_address_at(
+          pc, constant_pool, access, ConstantPoolEntry::INTPTR)) = target;
+      return;
+    }
+  }
+
   Instr instr1 = instr_at(pc);
   Instr instr2 = instr_at(pc + kInstrSize);
   // Interpret 2 instructions generated by lis/ori