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 /*

  * Copyright (c) 1999, 2010, Oracle and/or its affiliates. All rights reserved.

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * This code is free software; you can redistribute it and/or modify it

  * under the terms of the GNU General Public License version 2 only, as

  * published by the Free Software Foundation.

  *

  * This code is distributed in the hope that it will be useful, but WITHOUT

  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 #include "precompiled.hpp"

 #include "c1/c1_MacroAssembler.hpp"

 #include "c1/c1_Runtime1.hpp"

 #include "classfile/systemDictionary.hpp"

 #include "gc_interface/collectedHeap.hpp"

 #include "interpreter/interpreter.hpp"

 #include "oops/arrayOop.hpp"

 #include "oops/markOop.hpp"

 #include "runtime/basicLock.hpp"

 #include "runtime/biasedLocking.hpp"

 #include "runtime/os.hpp"

 #include "runtime/stubRoutines.hpp"

 int C1_MacroAssembler::lock_object(Register hdr, Register obj, Register disp_hdr, Register scratch, Label& slow_case) {

   const int aligned_mask = BytesPerWord -1;

   const int hdr_offset = oopDesc::mark_offset_in_bytes();

   assert(hdr == rax, "hdr must be rax, for the cmpxchg instruction");

   assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different");

   Label done;

   int null_check_offset = -1;

   verify_oop(obj);

   // save object being locked into the BasicObjectLock

   movptr(Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()), obj);

   if (UseBiasedLocking) {

     assert(scratch != noreg, "should have scratch register at this point");

     null_check_offset = biased_locking_enter(disp_hdr, obj, hdr, scratch, false, done, &slow_case);

   } else {

     null_check_offset = offset();

   }

   // Load object header

   movptr(hdr, Address(obj, hdr_offset));

   // and mark it as unlocked

   orptr(hdr, markOopDesc::unlocked_value);

   // save unlocked object header into the displaced header location on the stack

   movptr(Address(disp_hdr, 0), hdr);

   // test if object header is still the same (i.e. unlocked), and if so, store the

   // displaced header address in the object header - if it is not the same, get the

   // object header instead

   if (os::is_MP()) MacroAssembler::lock(); // must be immediately before cmpxchg!

   cmpxchgptr(disp_hdr, Address(obj, hdr_offset));

   // if the object header was the same, we're done

   if (PrintBiasedLockingStatistics) {

     cond_inc32(Assembler::equal,

                ExternalAddress((address)BiasedLocking::fast_path_entry_count_addr()));

   }

   jcc(Assembler::equal, done);

   // if the object header was not the same, it is now in the hdr register

   // => test if it is a stack pointer into the same stack (recursive locking), i.e.:

   //

   // 1) (hdr & aligned_mask) == 0

   // 2) rsp <= hdr

   // 3) hdr <= rsp + page_size

   //

   // these 3 tests can be done by evaluating the following expression:

   //

   // (hdr - rsp) & (aligned_mask - page_size)

   //

   // assuming both the stack pointer and page_size have their least

   // significant 2 bits cleared and page_size is a power of 2

   subptr(hdr, rsp);

   andptr(hdr, aligned_mask - os::vm_page_size());

   // for recursive locking, the result is zero => save it in the displaced header

   // location (NULL in the displaced hdr location indicates recursive locking)

   movptr(Address(disp_hdr, 0), hdr);

   // otherwise we don't care about the result and handle locking via runtime call

   jcc(Assembler::notZero, slow_case);

   // done

   bind(done);

   return null_check_offset;

 }

 void C1_MacroAssembler::unlock_object(Register hdr, Register obj, Register disp_hdr, Label& slow_case) {

   const int aligned_mask = BytesPerWord -1;

   const int hdr_offset = oopDesc::mark_offset_in_bytes();

   assert(disp_hdr == rax, "disp_hdr must be rax, for the cmpxchg instruction");

   assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different");

   Label done;

   if (UseBiasedLocking) {

     // load object

     movptr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()));

     biased_locking_exit(obj, hdr, done);

   }

   // load displaced header

   movptr(hdr, Address(disp_hdr, 0));

   // if the loaded hdr is NULL we had recursive locking

   testptr(hdr, hdr);

   // if we had recursive locking, we are done

   jcc(Assembler::zero, done);

   if (!UseBiasedLocking) {

     // load object

     movptr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()));

   }

   verify_oop(obj);

   // test if object header is pointing to the displaced header, and if so, restore

   // the displaced header in the object - if the object header is not pointing to

   // the displaced header, get the object header instead

   if (os::is_MP()) MacroAssembler::lock(); // must be immediately before cmpxchg!

   cmpxchgptr(hdr, Address(obj, hdr_offset));

   // if the object header was not pointing to the displaced header,

   // we do unlocking via runtime call

   jcc(Assembler::notEqual, slow_case);

   // done

   bind(done);

 }

 // Defines obj, preserves var_size_in_bytes

 void C1_MacroAssembler::try_allocate(Register obj, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2, Label& slow_case) {

   if (UseTLAB) {

     tlab_allocate(obj, var_size_in_bytes, con_size_in_bytes, t1, t2, slow_case);

   } else {

     eden_allocate(obj, var_size_in_bytes, con_size_in_bytes, t1, slow_case);

   }

 }

 void C1_MacroAssembler::initialize_header(Register obj, Register klass, Register len, Register t1, Register t2) {

   assert_different_registers(obj, klass, len);

   if (UseBiasedLocking && !len->is_valid()) {

     assert_different_registers(obj, klass, len, t1, t2);

     movptr(t1, Address(klass, Klass::prototype_header_offset_in_bytes() + klassOopDesc::klass_part_offset_in_bytes()));

     movptr(Address(obj, oopDesc::mark_offset_in_bytes()), t1);

   } else {

     // This assumes that all prototype bits fit in an int32_t

     movptr(Address(obj, oopDesc::mark_offset_in_bytes ()), (int32_t)(intptr_t)markOopDesc::prototype());

   }

 #ifdef _LP64

   if (UseCompressedOops) { // Take care not to kill klass

     movptr(t1, klass);

     encode_heap_oop_not_null(t1);

     movl(Address(obj, oopDesc::klass_offset_in_bytes()), t1);

   } else

 #endif

   {

     movptr(Address(obj, oopDesc::klass_offset_in_bytes()), klass);

   }

   if (len->is_valid()) {

     movl(Address(obj, arrayOopDesc::length_offset_in_bytes()), len);

   }

 #ifdef _LP64

   else if (UseCompressedOops) {

     xorptr(t1, t1);

     store_klass_gap(obj, t1);

   }

 #endif

 }

 // preserves obj, destroys len_in_bytes

 void C1_MacroAssembler::initialize_body(Register obj, Register len_in_bytes, int hdr_size_in_bytes, Register t1) {

   Label done;

   assert(obj != len_in_bytes && obj != t1 && t1 != len_in_bytes, "registers must be different");

   assert((hdr_size_in_bytes & (BytesPerWord - 1)) == 0, "header size is not a multiple of BytesPerWord");

   Register index = len_in_bytes;

   // index is positive and ptr sized

   subptr(index, hdr_size_in_bytes);

   jcc(Assembler::zero, done);

   // initialize topmost word, divide index by 2, check if odd and test if zero

   // note: for the remaining code to work, index must be a multiple of BytesPerWord

 #ifdef ASSERT

   { Label L;

     testptr(index, BytesPerWord - 1);

     jcc(Assembler::zero, L);

     stop("index is not a multiple of BytesPerWord");

     bind(L);

   }

 #endif

   xorptr(t1, t1);    // use _zero reg to clear memory (shorter code)

   if (UseIncDec) {

     shrptr(index, 3);  // divide by 8/16 and set carry flag if bit 2 was set

   } else {

     shrptr(index, 2);  // use 2 instructions to avoid partial flag stall

     shrptr(index, 1);

   }

 #ifndef _LP64

   // index could have been not a multiple of 8 (i.e., bit 2 was set)

   { Label even;

     // note: if index was a multiple of 8, than it cannot

     //       be 0 now otherwise it must have been 0 before

     //       => if it is even, we don't need to check for 0 again

     jcc(Assembler::carryClear, even);

     // clear topmost word (no jump needed if conditional assignment would work here)

     movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - 0*BytesPerWord), t1);

     // index could be 0 now, need to check again

     jcc(Assembler::zero, done);

     bind(even);

   }

 #endif // !_LP64

   // initialize remaining object fields: rdx is a multiple of 2 now

   { Label loop;

     bind(loop);

     movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - 1*BytesPerWord), t1);

     NOT_LP64(movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - 2*BytesPerWord), t1);)

     decrement(index);

     jcc(Assembler::notZero, loop);

   }

   // done

   bind(done);

 }

 void C1_MacroAssembler::allocate_object(Register obj, Register t1, Register t2, int header_size, int object_size, Register klass, Label& slow_case) {

   assert(obj == rax, "obj must be in rax, for cmpxchg");

   assert(obj != t1 && obj != t2 && t1 != t2, "registers must be different"); // XXX really?

   assert(header_size >= 0 && object_size >= header_size, "illegal sizes");

   try_allocate(obj, noreg, object_size * BytesPerWord, t1, t2, slow_case);

   initialize_object(obj, klass, noreg, object_size * HeapWordSize, t1, t2);

 }

 void C1_MacroAssembler::initialize_object(Register obj, Register klass, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2) {

   assert((con_size_in_bytes & MinObjAlignmentInBytesMask) == 0,

          "con_size_in_bytes is not multiple of alignment");

   const int hdr_size_in_bytes = instanceOopDesc::header_size() * HeapWordSize;

   initialize_header(obj, klass, noreg, t1, t2);

   // clear rest of allocated space

   const Register t1_zero = t1;

   const Register index = t2;

   const int threshold = 6 * BytesPerWord;   // approximate break even point for code size (see comments below)

   if (var_size_in_bytes != noreg) {

     mov(index, var_size_in_bytes);

     initialize_body(obj, index, hdr_size_in_bytes, t1_zero);

   } else if (con_size_in_bytes <= threshold) {

     // use explicit null stores

     // code size = 2 + 3*n bytes (n = number of fields to clear)

     xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code)

     for (int i = hdr_size_in_bytes; i < con_size_in_bytes; i += BytesPerWord)

       movptr(Address(obj, i), t1_zero);

   } else if (con_size_in_bytes > hdr_size_in_bytes) {

     // use loop to null out the fields

     // code size = 16 bytes for even n (n = number of fields to clear)

     // initialize last object field first if odd number of fields

     xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code)

     movptr(index, (con_size_in_bytes - hdr_size_in_bytes) >> 3);

     // initialize last object field if constant size is odd

     if (((con_size_in_bytes - hdr_size_in_bytes) & 4) != 0)

       movptr(Address(obj, con_size_in_bytes - (1*BytesPerWord)), t1_zero);

     // initialize remaining object fields: rdx is a multiple of 2

     { Label loop;

       bind(loop);

       movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - (1*BytesPerWord)),

              t1_zero);

       NOT_LP64(movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - (2*BytesPerWord)),

              t1_zero);)

       decrement(index);

       jcc(Assembler::notZero, loop);

     }

   }

   if (CURRENT_ENV->dtrace_alloc_probes()) {

     assert(obj == rax, "must be");

     call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));

   }

   verify_oop(obj);

 }

 void C1_MacroAssembler::allocate_array(Register obj, Register len, Register t1, Register t2, int header_size, Address::ScaleFactor f, Register klass, Label& slow_case) {

   assert(obj == rax, "obj must be in rax, for cmpxchg");

   assert_different_registers(obj, len, t1, t2, klass);

   // determine alignment mask

   assert(!(BytesPerWord & 1), "must be a multiple of 2 for masking code to work");

   // check for negative or excessive length

   cmpptr(len, (int32_t)max_array_allocation_length);

   jcc(Assembler::above, slow_case);

   const Register arr_size = t2; // okay to be the same

   // align object end

   movptr(arr_size, (int32_t)header_size * BytesPerWord + MinObjAlignmentInBytesMask);

   lea(arr_size, Address(arr_size, len, f));

   andptr(arr_size, ~MinObjAlignmentInBytesMask);

   try_allocate(obj, arr_size, 0, t1, t2, slow_case);

   initialize_header(obj, klass, len, t1, t2);

   // clear rest of allocated space

   const Register len_zero = len;

   initialize_body(obj, arr_size, header_size * BytesPerWord, len_zero);

   if (CURRENT_ENV->dtrace_alloc_probes()) {

     assert(obj == rax, "must be");

     call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));

   }

   verify_oop(obj);

 }

 void C1_MacroAssembler::inline_cache_check(Register receiver, Register iCache) {

   verify_oop(receiver);

   // explicit NULL check not needed since load from [klass_offset] causes a trap

   // check against inline cache

   assert(!MacroAssembler::needs_explicit_null_check(oopDesc::klass_offset_in_bytes()), "must add explicit null check");

   int start_offset = offset();

   if (UseCompressedOops) {

     load_klass(rscratch1, receiver);

     cmpptr(rscratch1, iCache);

   } else {

     cmpptr(iCache, Address(receiver, oopDesc::klass_offset_in_bytes()));

   }

   // if icache check fails, then jump to runtime routine

   // Note: RECEIVER must still contain the receiver!

   jump_cc(Assembler::notEqual,

           RuntimeAddress(SharedRuntime::get_ic_miss_stub()));

   const int ic_cmp_size = LP64_ONLY(10) NOT_LP64(9);

   assert(UseCompressedOops || offset() - start_offset == ic_cmp_size, "check alignment in emit_method_entry");

 }

 void C1_MacroAssembler::build_frame(int frame_size_in_bytes) {

   // Make sure there is enough stack space for this method's activation.

   // Note that we do this before doing an enter(). This matches the

   // ordering of C2's stack overflow check / rsp decrement and allows

   // the SharedRuntime stack overflow handling to be consistent

   // between the two compilers.

   generate_stack_overflow_check(frame_size_in_bytes);

   push(rbp);

 #ifdef TIERED

   // c2 leaves fpu stack dirty. Clean it on entry

   if (UseSSE < 2 ) {

     empty_FPU_stack();

   }

 #endif // TIERED

   decrement(rsp, frame_size_in_bytes); // does not emit code for frame_size == 0

 }

 void C1_MacroAssembler::remove_frame(int frame_size_in_bytes) {

   increment(rsp, frame_size_in_bytes);  // Does not emit code for frame_size == 0

   pop(rbp);

 }

 void C1_MacroAssembler::unverified_entry(Register receiver, Register ic_klass) {

   if (C1Breakpoint) int3();

   inline_cache_check(receiver, ic_klass);

 }

 void C1_MacroAssembler::verified_entry() {

   if (C1Breakpoint)int3();

   // build frame

   verify_FPU(0, "method_entry");

 }

 #ifndef PRODUCT

 void C1_MacroAssembler::verify_stack_oop(int stack_offset) {

   if (!VerifyOops) return;

   verify_oop_addr(Address(rsp, stack_offset));

 }

 void C1_MacroAssembler::verify_not_null_oop(Register r) {

   if (!VerifyOops) return;

   Label not_null;

   testptr(r, r);

   jcc(Assembler::notZero, not_null);

   stop("non-null oop required");

   bind(not_null);

   verify_oop(r);

 }

 void C1_MacroAssembler::invalidate_registers(bool inv_rax, bool inv_rbx, bool inv_rcx, bool inv_rdx, bool inv_rsi, bool inv_rdi) {

 #ifdef ASSERT

   if (inv_rax) movptr(rax, 0xDEAD);

   if (inv_rbx) movptr(rbx, 0xDEAD);

   if (inv_rcx) movptr(rcx, 0xDEAD);

   if (inv_rdx) movptr(rdx, 0xDEAD);

   if (inv_rsi) movptr(rsi, 0xDEAD);

   if (inv_rdi) movptr(rdi, 0xDEAD);

 #endif

 }

 #endif // ifndef PRODUCT