MIPS: Use JIC/JIALC offset when possible

src/mips/assembler-mips.cc

 // 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.
 //
@@ skipping 1919 matching lines @@
 
 void Assembler::lui(Register rd, int32_t j) {
   DCHECK(is_uint16(j));
   GenInstrImmediate(LUI, zero_reg, rd, j);
 }
 
 
 void Assembler::aui(Register rt, Register rs, int32_t j) {
   // This instruction uses same opcode as 'lui'. The difference in encoding is
   // 'lui' has zero reg. for rs field.
+  DCHECK(IsMipsArchVariant(kMips32r6));
   DCHECK(!(rs.is(zero_reg)));
   DCHECK(is_uint16(j));
   GenInstrImmediate(LUI, rs, rt, j);
 }
 
 // ---------PC-Relative instructions-----------
 
 void Assembler::addiupc(Register rs, int32_t imm19) {
   DCHECK(IsMipsArchVariant(kMips32r6));
   DCHECK(rs.is_valid() && is_int19(imm19));
@@ skipping 1243 matching lines @@
 Address Assembler::target_address_at(Address pc) {
   Instr instr1 = instr_at(pc);
   Instr instr2 = instr_at(pc + kInstrSize);
   // Interpret 2 instructions generated by li: lui/ori
   if (IsLui(instr1) && IsOri(instr2)) {
     // Assemble the 32 bit value.
     return reinterpret_cast<Address>((GetImmediate16(instr1) << kLuiShift) |
                                      GetImmediate16(instr2));
   }
 
+  if (IsLui(instr1) && IsJicOrJialc(instr2)) {
+    // Assemble the 32 bit value.

[ivica.bogosavljevic, 2016/12/12 13:29:39]

You already checked IsLui in the previous if statement, and you are calling the
same function again.

make two nested if's or save the value of IsLui to a variable in order to avoid
calling it two times.

+    return reinterpret_cast<Address>(CreateTargetAddress(instr1, instr2));
+  }
+
   // We should never get here, force a bad address if we do.
   UNREACHABLE();
   return (Address)0x0;
 }
 
 
 // MIPS and ia32 use opposite encoding for qNaN and sNaN, such that ia32
 // qNaN is a MIPS sNaN, and ia32 sNaN is MIPS qNaN. If running from a heap
 // snapshot generated on ia32, the resulting MIPS sNaN must be quieted.
 // OS::nan_value() returns a qNaN.
@@ skipping 46 matching lines @@
 
   if (icache_flush_mode != SKIP_ICACHE_FLUSH) {
     Assembler::FlushICache(isolate, pc, 2 * sizeof(int32_t));
   }
 }
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_MIPS