src/share/vm/opto/regmask.hpp

Wed, 03 Jun 2015 14:22:57 +0200

author
roland
date
Wed, 03 Jun 2015 14:22:57 +0200
changeset 7859
c1c199dde5c9
parent 7598
ddce0b7cee93
child 7994
04ff2f6cd0eb
permissions
-rw-r--r--

8077504: Unsafe load can loose control dependency and cause crash
Summary: Node::depends_only_on_test() should return false for Unsafe loads
Reviewed-by: kvn, adinn

     1 /*
     2  * Copyright (c) 1997, 2015, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
    20  * or visit www.oracle.com if you need additional information or have any
    21  * questions.
    22  *
    23  */
    25 #ifndef SHARE_VM_OPTO_REGMASK_HPP
    26 #define SHARE_VM_OPTO_REGMASK_HPP
    28 #include "code/vmreg.hpp"
    29 #include "libadt/port.hpp"
    30 #include "opto/optoreg.hpp"
    31 #if defined ADGLOBALS_MD_HPP
    32 # include ADGLOBALS_MD_HPP
    33 #elif defined TARGET_ARCH_MODEL_x86_32
    34 # include "adfiles/adGlobals_x86_32.hpp"
    35 #elif defined TARGET_ARCH_MODEL_x86_64
    36 # include "adfiles/adGlobals_x86_64.hpp"
    37 #elif defined TARGET_ARCH_MODEL_sparc
    38 # include "adfiles/adGlobals_sparc.hpp"
    39 #elif defined TARGET_ARCH_MODEL_zero
    40 # include "adfiles/adGlobals_zero.hpp"
    41 #elif defined TARGET_ARCH_MODEL_ppc_64
    42 # include "adfiles/adGlobals_ppc_64.hpp"
    43 #endif
    45 // Some fun naming (textual) substitutions:
    46 //
    47 // RegMask::get_low_elem() ==> RegMask::find_first_elem()
    48 // RegMask::Special        ==> RegMask::Empty
    49 // RegMask::_flags         ==> RegMask::is_AllStack()
    50 // RegMask::operator<<=()  ==> RegMask::Insert()
    51 // RegMask::operator>>=()  ==> RegMask::Remove()
    52 // RegMask::Union()        ==> RegMask::OR
    53 // RegMask::Inter()        ==> RegMask::AND
    54 //
    55 // OptoRegister::RegName   ==> OptoReg::Name
    56 //
    57 // OptoReg::stack0()       ==> _last_Mach_Reg  or ZERO in core version
    58 //
    59 // numregs in chaitin      ==> proper degree in chaitin
    61 //-------------Non-zero bit search methods used by RegMask---------------------
    62 // Find lowest 1, or return 32 if empty
    63 int find_lowest_bit( uint32 mask );
    64 // Find highest 1, or return 32 if empty
    65 int find_hihghest_bit( uint32 mask );
    67 //------------------------------RegMask----------------------------------------
    68 // The ADL file describes how to print the machine-specific registers, as well
    69 // as any notion of register classes.  We provide a register mask, which is
    70 // just a collection of Register numbers.
    72 // The ADLC defines 2 macros, RM_SIZE and FORALL_BODY.
    73 // RM_SIZE is the size of a register mask in words.
    74 // FORALL_BODY replicates a BODY macro once per word in the register mask.
    75 // The usage is somewhat clumsy and limited to the regmask.[h,c]pp files.
    76 // However, it means the ADLC can redefine the unroll macro and all loops
    77 // over register masks will be unrolled by the correct amount.
    79 class RegMask VALUE_OBJ_CLASS_SPEC {
    80   union {
    81     double _dummy_force_double_alignment[RM_SIZE>>1];
    82     // Array of Register Mask bits.  This array is large enough to cover
    83     // all the machine registers and all parameters that need to be passed
    84     // on the stack (stack registers) up to some interesting limit.  Methods
    85     // that need more parameters will NOT be compiled.  On Intel, the limit
    86     // is something like 90+ parameters.
    87     int _A[RM_SIZE];
    88   };
    90   enum {
    91     _WordBits    = BitsPerInt,
    92     _LogWordBits = LogBitsPerInt,
    93     _RM_SIZE     = RM_SIZE   // local constant, imported, then hidden by #undef
    94   };
    96 public:
    97   enum { CHUNK_SIZE = RM_SIZE*_WordBits };
    99   // SlotsPerLong is 2, since slots are 32 bits and longs are 64 bits.
   100   // Also, consider the maximum alignment size for a normally allocated
   101   // value.  Since we allocate register pairs but not register quads (at
   102   // present), this alignment is SlotsPerLong (== 2).  A normally
   103   // aligned allocated register is either a single register, or a pair
   104   // of adjacent registers, the lower-numbered being even.
   105   // See also is_aligned_Pairs() below, and the padding added before
   106   // Matcher::_new_SP to keep allocated pairs aligned properly.
   107   // If we ever go to quad-word allocations, SlotsPerQuad will become
   108   // the controlling alignment constraint.  Note that this alignment
   109   // requirement is internal to the allocator, and independent of any
   110   // particular platform.
   111   enum { SlotsPerLong = 2,
   112          SlotsPerVecS = 1,
   113          SlotsPerVecD = 2,
   114          SlotsPerVecX = 4,
   115          SlotsPerVecY = 8 };
   117   // A constructor only used by the ADLC output.  All mask fields are filled
   118   // in directly.  Calls to this look something like RM(1,2,3,4);
   119   RegMask(
   120 #   define BODY(I) int a##I,
   121     FORALL_BODY
   122 #   undef BODY
   123     int dummy = 0 ) {
   124 #   define BODY(I) _A[I] = a##I;
   125     FORALL_BODY
   126 #   undef BODY
   127   }
   129   // Handy copying constructor
   130   RegMask( RegMask *rm ) {
   131 #   define BODY(I) _A[I] = rm->_A[I];
   132     FORALL_BODY
   133 #   undef BODY
   134   }
   136   // Construct an empty mask
   137   RegMask( ) { Clear(); }
   139   // Construct a mask with a single bit
   140   RegMask( OptoReg::Name reg ) { Clear(); Insert(reg); }
   142   // Check for register being in mask
   143   int Member( OptoReg::Name reg ) const {
   144     assert( reg < CHUNK_SIZE, "" );
   145     return _A[reg>>_LogWordBits] & (1<<(reg&(_WordBits-1)));
   146   }
   148   // The last bit in the register mask indicates that the mask should repeat
   149   // indefinitely with ONE bits.  Returns TRUE if mask is infinite or
   150   // unbounded in size.  Returns FALSE if mask is finite size.
   151   int is_AllStack() const { return _A[RM_SIZE-1] >> (_WordBits-1); }
   153   // Work around an -xO3 optimization problme in WS6U1. The old way:
   154   //   void set_AllStack() { _A[RM_SIZE-1] |= (1<<(_WordBits-1)); }
   155   // will cause _A[RM_SIZE-1] to be clobbered, not updated when set_AllStack()
   156   // follows an Insert() loop, like the one found in init_spill_mask(). Using
   157   // Insert() instead works because the index into _A in computed instead of
   158   // constant.  See bug 4665841.
   159   void set_AllStack() { Insert(OptoReg::Name(CHUNK_SIZE-1)); }
   161   // Test for being a not-empty mask.
   162   int is_NotEmpty( ) const {
   163     int tmp = 0;
   164 #   define BODY(I) tmp |= _A[I];
   165     FORALL_BODY
   166 #   undef BODY
   167     return tmp;
   168   }
   170   // Find lowest-numbered register from mask, or BAD if mask is empty.
   171   OptoReg::Name find_first_elem() const {
   172     int base, bits;
   173 #   define BODY(I) if( (bits = _A[I]) != 0 ) base = I<<_LogWordBits; else
   174     FORALL_BODY
   175 #   undef BODY
   176       { base = OptoReg::Bad; bits = 1<<0; }
   177     return OptoReg::Name(base + find_lowest_bit(bits));
   178   }
   179   // Get highest-numbered register from mask, or BAD if mask is empty.
   180   OptoReg::Name find_last_elem() const {
   181     int base, bits;
   182 #   define BODY(I) if( (bits = _A[RM_SIZE-1-I]) != 0 ) base = (RM_SIZE-1-I)<<_LogWordBits; else
   183     FORALL_BODY
   184 #   undef BODY
   185       { base = OptoReg::Bad; bits = 1<<0; }
   186     return OptoReg::Name(base + find_hihghest_bit(bits));
   187   }
   189   // Find the lowest-numbered register pair in the mask.  Return the
   190   // HIGHEST register number in the pair, or BAD if no pairs.
   191   // Assert that the mask contains only bit pairs.
   192   OptoReg::Name find_first_pair() const;
   194   // Clear out partial bits; leave only aligned adjacent bit pairs.
   195   void clear_to_pairs();
   196   // Smear out partial bits; leave only aligned adjacent bit pairs.
   197   void smear_to_pairs();
   198   // Verify that the mask contains only aligned adjacent bit pairs
   199   void verify_pairs() const { assert( is_aligned_pairs(), "mask is not aligned, adjacent pairs" ); }
   200   // Test that the mask contains only aligned adjacent bit pairs
   201   bool is_aligned_pairs() const;
   203   // mask is a pair of misaligned registers
   204   bool is_misaligned_pair() const { return Size()==2 && !is_aligned_pairs(); }
   205   // Test for single register
   206   int is_bound1() const;
   207   // Test for a single adjacent pair
   208   int is_bound_pair() const;
   209   // Test for a single adjacent set of ideal register's size.
   210   int is_bound(uint ireg) const {
   211     if (is_vector(ireg)) {
   212       if (is_bound_set(num_registers(ireg)))
   213         return true;
   214     } else if (is_bound1() || is_bound_pair()) {
   215       return true;
   216     }
   217     return false;
   218   }
   220   // Find the lowest-numbered register set in the mask.  Return the
   221   // HIGHEST register number in the set, or BAD if no sets.
   222   // Assert that the mask contains only bit sets.
   223   OptoReg::Name find_first_set(const int size) const;
   225   // Clear out partial bits; leave only aligned adjacent bit sets of size.
   226   void clear_to_sets(const int size);
   227   // Smear out partial bits to aligned adjacent bit sets.
   228   void smear_to_sets(const int size);
   229   // Verify that the mask contains only aligned adjacent bit sets
   230   void verify_sets(int size) const { assert(is_aligned_sets(size), "mask is not aligned, adjacent sets"); }
   231   // Test that the mask contains only aligned adjacent bit sets
   232   bool is_aligned_sets(const int size) const;
   234   // mask is a set of misaligned registers
   235   bool is_misaligned_set(int size) const { return (int)Size()==size && !is_aligned_sets(size);}
   237   // Test for a single adjacent set
   238   int is_bound_set(const int size) const;
   240   static bool is_vector(uint ireg);
   241   static int num_registers(uint ireg);
   243   // Fast overlap test.  Non-zero if any registers in common.
   244   int overlap( const RegMask &rm ) const {
   245     return
   246 #   define BODY(I) (_A[I] & rm._A[I]) |
   247     FORALL_BODY
   248 #   undef BODY
   249     0 ;
   250   }
   252   // Special test for register pressure based splitting
   253   // UP means register only, Register plus stack, or stack only is DOWN
   254   bool is_UP() const;
   256   // Clear a register mask
   257   void Clear( ) {
   258 #   define BODY(I) _A[I] = 0;
   259     FORALL_BODY
   260 #   undef BODY
   261   }
   263   // Fill a register mask with 1's
   264   void Set_All( ) {
   265 #   define BODY(I) _A[I] = -1;
   266     FORALL_BODY
   267 #   undef BODY
   268   }
   270   // Insert register into mask
   271   void Insert( OptoReg::Name reg ) {
   272     assert( reg < CHUNK_SIZE, "" );
   273     _A[reg>>_LogWordBits] |= (1<<(reg&(_WordBits-1)));
   274   }
   276   // Remove register from mask
   277   void Remove( OptoReg::Name reg ) {
   278     assert( reg < CHUNK_SIZE, "" );
   279     _A[reg>>_LogWordBits] &= ~(1<<(reg&(_WordBits-1)));
   280   }
   282   // OR 'rm' into 'this'
   283   void OR( const RegMask &rm ) {
   284 #   define BODY(I) this->_A[I] |= rm._A[I];
   285     FORALL_BODY
   286 #   undef BODY
   287   }
   289   // AND 'rm' into 'this'
   290   void AND( const RegMask &rm ) {
   291 #   define BODY(I) this->_A[I] &= rm._A[I];
   292     FORALL_BODY
   293 #   undef BODY
   294   }
   296   // Subtract 'rm' from 'this'
   297   void SUBTRACT( const RegMask &rm ) {
   298 #   define BODY(I) _A[I] &= ~rm._A[I];
   299     FORALL_BODY
   300 #   undef BODY
   301   }
   303   // Compute size of register mask: number of bits
   304   uint Size() const;
   306 #ifndef PRODUCT
   307   void print() const { dump(); }
   308   void dump(outputStream *st = tty) const; // Print a mask
   309 #endif
   311   static const RegMask Empty;   // Common empty mask
   313   static bool can_represent(OptoReg::Name reg) {
   314     // NOTE: -1 in computation reflects the usage of the last
   315     //       bit of the regmask as an infinite stack flag and
   316     //       -7 is to keep mask aligned for largest value (VecY).
   317     return (int)reg < (int)(CHUNK_SIZE-1);
   318   }
   319   static bool can_represent_arg(OptoReg::Name reg) {
   320     // NOTE: -SlotsPerVecY in computation reflects the need
   321     //       to keep mask aligned for largest value (VecY).
   322     return (int)reg < (int)(CHUNK_SIZE-SlotsPerVecY);
   323   }
   324 };
   326 // Do not use this constant directly in client code!
   327 #undef RM_SIZE
   329 #endif // SHARE_VM_OPTO_REGMASK_HPP

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