hotspot/src/share/vm/opto/regmask.hpp
changeset 1 489c9b5090e2
child 5547 f4b087cbb361
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/opto/regmask.hpp	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,264 @@
+/*
+ * Copyright 1997-2006 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+// Some fun naming (textual) substitutions:
+//
+// RegMask::get_low_elem() ==> RegMask::find_first_elem()
+// RegMask::Special        ==> RegMask::Empty
+// RegMask::_flags         ==> RegMask::is_AllStack()
+// RegMask::operator<<=()  ==> RegMask::Insert()
+// RegMask::operator>>=()  ==> RegMask::Remove()
+// RegMask::Union()        ==> RegMask::OR
+// RegMask::Inter()        ==> RegMask::AND
+//
+// OptoRegister::RegName   ==> OptoReg::Name
+//
+// OptoReg::stack0()       ==> _last_Mach_Reg  or ZERO in core version
+//
+// numregs in chaitin      ==> proper degree in chaitin
+
+//-------------Non-zero bit search methods used by RegMask---------------------
+// Find lowest 1, or return 32 if empty
+int find_lowest_bit( uint32 mask );
+// Find highest 1, or return 32 if empty
+int find_hihghest_bit( uint32 mask );
+
+//------------------------------RegMask----------------------------------------
+// The ADL file describes how to print the machine-specific registers, as well
+// as any notion of register classes.  We provide a register mask, which is
+// just a collection of Register numbers.
+
+// The ADLC defines 2 macros, RM_SIZE and FORALL_BODY.
+// RM_SIZE is the size of a register mask in words.
+// FORALL_BODY replicates a BODY macro once per word in the register mask.
+// The usage is somewhat clumsy and limited to the regmask.[h,c]pp files.
+// However, it means the ADLC can redefine the unroll macro and all loops
+// over register masks will be unrolled by the correct amount.
+
+class RegMask VALUE_OBJ_CLASS_SPEC {
+  union {
+    double _dummy_force_double_alignment[RM_SIZE>>1];
+    // Array of Register Mask bits.  This array is large enough to cover
+    // all the machine registers and all parameters that need to be passed
+    // on the stack (stack registers) up to some interesting limit.  Methods
+    // that need more parameters will NOT be compiled.  On Intel, the limit
+    // is something like 90+ parameters.
+    int _A[RM_SIZE];
+  };
+
+  enum {
+    _WordBits    = BitsPerInt,
+    _LogWordBits = LogBitsPerInt,
+    _RM_SIZE     = RM_SIZE   // local constant, imported, then hidden by #undef
+  };
+
+public:
+  enum { CHUNK_SIZE = RM_SIZE*_WordBits };
+
+  // SlotsPerLong is 2, since slots are 32 bits and longs are 64 bits.
+  // Also, consider the maximum alignment size for a normally allocated
+  // value.  Since we allocate register pairs but not register quads (at
+  // present), this alignment is SlotsPerLong (== 2).  A normally
+  // aligned allocated register is either a single register, or a pair
+  // of adjacent registers, the lower-numbered being even.
+  // See also is_aligned_Pairs() below, and the padding added before
+  // Matcher::_new_SP to keep allocated pairs aligned properly.
+  // If we ever go to quad-word allocations, SlotsPerQuad will become
+  // the controlling alignment constraint.  Note that this alignment
+  // requirement is internal to the allocator, and independent of any
+  // particular platform.
+  enum { SlotsPerLong = 2 };
+
+  // A constructor only used by the ADLC output.  All mask fields are filled
+  // in directly.  Calls to this look something like RM(1,2,3,4);
+  RegMask(
+#   define BODY(I) int a##I,
+    FORALL_BODY
+#   undef BODY
+    int dummy = 0 ) {
+#   define BODY(I) _A[I] = a##I;
+    FORALL_BODY
+#   undef BODY
+  }
+
+  // Handy copying constructor
+  RegMask( RegMask *rm ) {
+#   define BODY(I) _A[I] = rm->_A[I];
+    FORALL_BODY
+#   undef BODY
+  }
+
+  // Construct an empty mask
+  RegMask( ) { Clear(); }
+
+  // Construct a mask with a single bit
+  RegMask( OptoReg::Name reg ) { Clear(); Insert(reg); }
+
+  // Check for register being in mask
+  int Member( OptoReg::Name reg ) const {
+    assert( reg < CHUNK_SIZE, "" );
+    return _A[reg>>_LogWordBits] & (1<<(reg&(_WordBits-1)));
+  }
+
+  // The last bit in the register mask indicates that the mask should repeat
+  // indefinitely with ONE bits.  Returns TRUE if mask is infinite or
+  // unbounded in size.  Returns FALSE if mask is finite size.
+  int is_AllStack() const { return _A[RM_SIZE-1] >> (_WordBits-1); }
+
+  // Work around an -xO3 optimization problme in WS6U1. The old way:
+  //   void set_AllStack() { _A[RM_SIZE-1] |= (1<<(_WordBits-1)); }
+  // will cause _A[RM_SIZE-1] to be clobbered, not updated when set_AllStack()
+  // follows an Insert() loop, like the one found in init_spill_mask(). Using
+  // Insert() instead works because the index into _A in computed instead of
+  // constant.  See bug 4665841.
+  void set_AllStack() { Insert(OptoReg::Name(CHUNK_SIZE-1)); }
+
+  // Test for being a not-empty mask.
+  int is_NotEmpty( ) const {
+    int tmp = 0;
+#   define BODY(I) tmp |= _A[I];
+    FORALL_BODY
+#   undef BODY
+    return tmp;
+  }
+
+  // Find lowest-numbered register from mask, or BAD if mask is empty.
+  OptoReg::Name find_first_elem() const {
+    int base, bits;
+#   define BODY(I) if( (bits = _A[I]) != 0 ) base = I<<_LogWordBits; else
+    FORALL_BODY
+#   undef BODY
+      { base = OptoReg::Bad; bits = 1<<0; }
+    return OptoReg::Name(base + find_lowest_bit(bits));
+  }
+  // Get highest-numbered register from mask, or BAD if mask is empty.
+  OptoReg::Name find_last_elem() const {
+    int base, bits;
+#   define BODY(I) if( (bits = _A[RM_SIZE-1-I]) != 0 ) base = (RM_SIZE-1-I)<<_LogWordBits; else
+    FORALL_BODY
+#   undef BODY
+      { base = OptoReg::Bad; bits = 1<<0; }
+    return OptoReg::Name(base + find_hihghest_bit(bits));
+  }
+
+  // Find the lowest-numbered register pair in the mask.  Return the
+  // HIGHEST register number in the pair, or BAD if no pairs.
+  // Assert that the mask contains only bit pairs.
+  OptoReg::Name find_first_pair() const;
+
+  // Clear out partial bits; leave only aligned adjacent bit pairs.
+  void ClearToPairs();
+  // Smear out partial bits; leave only aligned adjacent bit pairs.
+  void SmearToPairs();
+  // Verify that the mask contains only aligned adjacent bit pairs
+  void VerifyPairs() const { assert( is_aligned_Pairs(), "mask is not aligned, adjacent pairs" ); }
+  // Test that the mask contains only aligned adjacent bit pairs
+  bool is_aligned_Pairs() const;
+
+  // mask is a pair of misaligned registers
+  bool is_misaligned_Pair() const { return Size()==2 && !is_aligned_Pairs();}
+  // Test for single register
+  int is_bound1() const;
+  // Test for a single adjacent pair
+  int is_bound2() const;
+
+  // Fast overlap test.  Non-zero if any registers in common.
+  int overlap( const RegMask &rm ) const {
+    return
+#   define BODY(I) (_A[I] & rm._A[I]) |
+    FORALL_BODY
+#   undef BODY
+    0 ;
+  }
+
+  // Special test for register pressure based splitting
+  // UP means register only, Register plus stack, or stack only is DOWN
+  bool is_UP() const;
+
+  // Clear a register mask
+  void Clear( ) {
+#   define BODY(I) _A[I] = 0;
+    FORALL_BODY
+#   undef BODY
+  }
+
+  // Fill a register mask with 1's
+  void Set_All( ) {
+#   define BODY(I) _A[I] = -1;
+    FORALL_BODY
+#   undef BODY
+  }
+
+  // Insert register into mask
+  void Insert( OptoReg::Name reg ) {
+    assert( reg < CHUNK_SIZE, "" );
+    _A[reg>>_LogWordBits] |= (1<<(reg&(_WordBits-1)));
+  }
+
+  // Remove register from mask
+  void Remove( OptoReg::Name reg ) {
+    assert( reg < CHUNK_SIZE, "" );
+    _A[reg>>_LogWordBits] &= ~(1<<(reg&(_WordBits-1)));
+  }
+
+  // OR 'rm' into 'this'
+  void OR( const RegMask &rm ) {
+#   define BODY(I) this->_A[I] |= rm._A[I];
+    FORALL_BODY
+#   undef BODY
+  }
+
+  // AND 'rm' into 'this'
+  void AND( const RegMask &rm ) {
+#   define BODY(I) this->_A[I] &= rm._A[I];
+    FORALL_BODY
+#   undef BODY
+  }
+
+  // Subtract 'rm' from 'this'
+  void SUBTRACT( const RegMask &rm ) {
+#   define BODY(I) _A[I] &= ~rm._A[I];
+    FORALL_BODY
+#   undef BODY
+  }
+
+  // Compute size of register mask: number of bits
+  uint Size() const;
+
+#ifndef PRODUCT
+  void print() const { dump(); }
+  void dump() const;            // Print a mask
+#endif
+
+  static const RegMask Empty;   // Common empty mask
+
+  static bool can_represent(OptoReg::Name reg) {
+    // NOTE: -1 in computation reflects the usage of the last
+    //       bit of the regmask as an infinite stack flag.
+    return (int)reg < (int)(CHUNK_SIZE-1);
+  }
+};
+
+// Do not use this constant directly in client code!
+#undef RM_SIZE