1 /*

     2  * Copyright 1999-2007 Sun Microsystems, Inc.  All Rights Reserved.

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

     4  *

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

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

     7  * published by the Free Software Foundation.

     8  *

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

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

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

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

    13  * accompanied this code).

    14  *

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

    16  * 2 along with this work; if not, write to the Free Software Foundation,

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

    18  *

    19  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

    20  * CA 95054 USA or visit www.sun.com if you need additional information or

    21  * have any questions.

    22  *

    23  */

    24 

    25 #include "incls/_precompiled.incl"

    26 #include "incls/_c1_MacroAssembler_x86.cpp.incl"

    27 

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

    29   const int aligned_mask = 3;

    30   const int hdr_offset = oopDesc::mark_offset_in_bytes();

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

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

    33   assert(BytesPerWord == 4, "adjust aligned_mask and code");

    34   Label done;

    35   int null_check_offset = -1;

    36 

    37   verify_oop(obj);

    38 

    39   // save object being locked into the BasicObjectLock

    40   movl(Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()), obj);

    41 

    42   if (UseBiasedLocking) {

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

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

    45   } else {

    46     null_check_offset = offset();

    47   }

    48 

    49   // Load object header

    50   movl(hdr, Address(obj, hdr_offset));

    51   // and mark it as unlocked

    52   orl(hdr, markOopDesc::unlocked_value);

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

    54   movl(Address(disp_hdr, 0), hdr);

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

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

    57   // object header instead

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

    59   cmpxchg(disp_hdr, Address(obj, hdr_offset));

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

    61   if (PrintBiasedLockingStatistics) {

    62     cond_inc32(Assembler::equal,

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

    64   }

    65   jcc(Assembler::equal, done);

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

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

    68   //

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

    70   // 2) rsp <= hdr

    71   // 3) hdr <= rsp + page_size

    72   //

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

    74   //

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

    76   //

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

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

    79   subl(hdr, rsp);

    80   andl(hdr, aligned_mask - os::vm_page_size());

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

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

    83   movl(Address(disp_hdr, 0), hdr);

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

    85   jcc(Assembler::notZero, slow_case);

    86   // done

    87   bind(done);

    88   return null_check_offset;

    89 }

    90 

    91 

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

    93   const int aligned_mask = 3;

    94   const int hdr_offset = oopDesc::mark_offset_in_bytes();

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

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

    97   assert(BytesPerWord == 4, "adjust aligned_mask and code");

    98   Label done;

    99 

   100   if (UseBiasedLocking) {

   101     // load object

   102     movl(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()));

   103     biased_locking_exit(obj, hdr, done);

   104   }

   105 

   106   // load displaced header

   107   movl(hdr, Address(disp_hdr, 0));

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

   109   testl(hdr, hdr);

   110   // if we had recursive locking, we are done

   111   jcc(Assembler::zero, done);

   112   if (!UseBiasedLocking) {

   113     // load object

   114     movl(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()));

   115   }

   116   verify_oop(obj);

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

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

   119   // the displaced header, get the object header instead

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

   121   cmpxchg(hdr, Address(obj, hdr_offset));

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

   123   // we do unlocking via runtime call

   124   jcc(Assembler::notEqual, slow_case);

   125   // done

   126   bind(done);

   127 }

   128 

   129 

   130 // Defines obj, preserves var_size_in_bytes

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

   132   if (UseTLAB) {

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

   134   } else {

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

   136   }

   137 }

   138 

   139 

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

   141   assert_different_registers(obj, klass, len);

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

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

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

   145     movl(Address(obj, oopDesc::mark_offset_in_bytes()), t1);

   146   } else {

   147     movl(Address(obj, oopDesc::mark_offset_in_bytes ()), (int)markOopDesc::prototype());

   148   }

   149 

   150   movl(Address(obj, oopDesc::klass_offset_in_bytes()), klass);

   151   if (len->is_valid()) {

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

   153   }

   154 }

   155 

   156 

   157 // preserves obj, destroys len_in_bytes

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

   159   Label done;

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

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

   162   Register index = len_in_bytes;

   163   subl(index, hdr_size_in_bytes);

   164   jcc(Assembler::zero, done);

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

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

   167 #ifdef ASSERT

   168   { Label L;

   169     testl(index, BytesPerWord - 1);

   170     jcc(Assembler::zero, L);

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

   172     bind(L);

   173   }

   174 #endif

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

   176   if (UseIncDec) {

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

   178   } else {

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

   180     shrl(index, 1);

   181   }

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

   183   { Label even;

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

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

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

   187     jcc(Assembler::carryClear, even);

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

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

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

   191     jcc(Assembler::zero, done);

   192     bind(even);

   193   }

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

   195   { Label loop;

   196     bind(loop);

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

   198     movl(Address(obj, index, Address::times_8, hdr_size_in_bytes - 2*BytesPerWord), t1);

   199     decrement(index);

   200     jcc(Assembler::notZero, loop);

   201   }

   202 

   203   // done

   204   bind(done);

   205 }

   206 

   207 

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

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

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

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

   212 

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

   214 

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

   216 }

   217 

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

   219   assert((con_size_in_bytes & MinObjAlignmentInBytesMask) == 0,

   220          "con_size_in_bytes is not multiple of alignment");

   221   const int hdr_size_in_bytes = oopDesc::header_size_in_bytes();

   222 

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

   224 

   225   // clear rest of allocated space

   226   const Register t1_zero = t1;

   227   const Register index = t2;

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

   229   if (var_size_in_bytes != noreg) {

   230     movl(index, var_size_in_bytes);

   231     initialize_body(obj, index, hdr_size_in_bytes, t1_zero);

   232   } else if (con_size_in_bytes <= threshold) {

   233     // use explicit null stores

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

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

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

   237       movl(Address(obj, i), t1_zero);

   238   } else if (con_size_in_bytes > hdr_size_in_bytes) {

   239     // use loop to null out the fields

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

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

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

   243     movl(index, (con_size_in_bytes - hdr_size_in_bytes) >> 3);

   244     // initialize last object field if constant size is odd

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

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

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

   248     { Label loop;

   249       bind(loop);

   250       movl(Address(obj, index, Address::times_8,

   251         hdr_size_in_bytes - (1*BytesPerWord)), t1_zero);

   252       movl(Address(obj, index, Address::times_8,

   253         hdr_size_in_bytes - (2*BytesPerWord)), t1_zero);

   254       decrement(index);

   255       jcc(Assembler::notZero, loop);

   256     }

   257   }

   258 

   259   if (DTraceAllocProbes) {

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

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

   262   }

   263 

   264   verify_oop(obj);

   265 }

   266 

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

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

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

   270 

   271   // determine alignment mask

   272   assert(BytesPerWord == 4, "must be a multiple of 2 for masking code to work");

   273 

   274   // check for negative or excessive length

   275   cmpl(len, max_array_allocation_length);

   276   jcc(Assembler::above, slow_case);

   277 

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

   279   // align object end

   280   movl(arr_size, header_size * BytesPerWord + MinObjAlignmentInBytesMask);

   281   leal(arr_size, Address(arr_size, len, f));

   282   andl(arr_size, ~MinObjAlignmentInBytesMask);

   283 

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

   285 

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

   287 

   288   // clear rest of allocated space

   289   const Register len_zero = len;

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

   291 

   292   if (DTraceAllocProbes) {

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

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

   295   }

   296 

   297   verify_oop(obj);

   298 }

   299 

   300 

   301 

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

   303   verify_oop(receiver);

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

   305   // check against inline cache

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

   307   int start_offset = offset();

   308   cmpl(iCache, Address(receiver, oopDesc::klass_offset_in_bytes()));

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

   310   // Note: RECEIVER must still contain the receiver!

   311   jump_cc(Assembler::notEqual,

   312           RuntimeAddress(SharedRuntime::get_ic_miss_stub()));

   313   assert(offset() - start_offset == 9, "check alignment in emit_method_entry");

   314 }

   315 

   316 

   317 void C1_MacroAssembler::method_exit(bool restore_frame) {

   318   if (restore_frame) {

   319     leave();

   320   }

   321   ret(0);

   322 }

   323 

   324 

   325 void C1_MacroAssembler::build_frame(int frame_size_in_bytes) {

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

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

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

   329   // the SharedRuntime stack overflow handling to be consistent

   330   // between the two compilers.

   331   generate_stack_overflow_check(frame_size_in_bytes);

   332 

   333   enter();

   334 #ifdef TIERED

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

   336   if (UseSSE < 2 ) {

   337     empty_FPU_stack();

   338   }

   339 #endif // TIERED

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

   341 }

   342 

   343 

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

   345   if (C1Breakpoint) int3();

   346   inline_cache_check(receiver, ic_klass);

   347 }

   348 

   349 

   350 void C1_MacroAssembler::verified_entry() {

   351   if (C1Breakpoint)int3();

   352   // build frame

   353   verify_FPU(0, "method_entry");

   354 }

   355 

   356 

   357 #ifndef PRODUCT

   358 

   359 void C1_MacroAssembler::verify_stack_oop(int stack_offset) {

   360   if (!VerifyOops) return;

   361   verify_oop_addr(Address(rsp, stack_offset));

   362 }

   363 

   364 void C1_MacroAssembler::verify_not_null_oop(Register r) {

   365   if (!VerifyOops) return;

   366   Label not_null;

   367   testl(r, r);

   368   jcc(Assembler::notZero, not_null);

   369   stop("non-null oop required");

   370   bind(not_null);

   371   verify_oop(r);

   372 }

   373 

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

   375 #ifdef ASSERT

   376   if (inv_rax) movl(rax, 0xDEAD);

   377   if (inv_rbx) movl(rbx, 0xDEAD);

   378   if (inv_rcx) movl(rcx, 0xDEAD);

   379   if (inv_rdx) movl(rdx, 0xDEAD);

   380   if (inv_rsi) movl(rsi, 0xDEAD);

   381   if (inv_rdi) movl(rdi, 0xDEAD);

   382 #endif

   383 }

   384 

   385 #endif // ifndef PRODUCT