1 /*
2 * Copyright (c) 1997, 2006, 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.
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23 */
24
25 // Some fun naming (textual) substitutions:
26 //
27 // RegMask::get_low_elem() ==> RegMask::find_first_elem()
28 // RegMask::Special ==> RegMask::Empty
29 // RegMask::_flags ==> RegMask::is_AllStack()
30 // RegMask::operator<<=() ==> RegMask::Insert()
31 // RegMask::operator>>=() ==> RegMask::Remove()
32 // RegMask::Union() ==> RegMask::OR
33 // RegMask::Inter() ==> RegMask::AND
34 //
35 // OptoRegister::RegName ==> OptoReg::Name
36 //
37 // OptoReg::stack0() ==> _last_Mach_Reg or ZERO in core version
38 //
39 // numregs in chaitin ==> proper degree in chaitin
40
41 //-------------Non-zero bit search methods used by RegMask---------------------
42 // Find lowest 1, or return 32 if empty
43 int find_lowest_bit( uint32 mask );
44 // Find highest 1, or return 32 if empty
45 int find_hihghest_bit( uint32 mask );
46
47 //------------------------------RegMask----------------------------------------
48 // The ADL file describes how to print the machine-specific registers, as well
49 // as any notion of register classes. We provide a register mask, which is
50 // just a collection of Register numbers.
51
52 // The ADLC defines 2 macros, RM_SIZE and FORALL_BODY.
53 // RM_SIZE is the size of a register mask in words.
54 // FORALL_BODY replicates a BODY macro once per word in the register mask.
55 // The usage is somewhat clumsy and limited to the regmask.[h,c]pp files.
56 // However, it means the ADLC can redefine the unroll macro and all loops
57 // over register masks will be unrolled by the correct amount.
58
59 class RegMask VALUE_OBJ_CLASS_SPEC {
60 union {
61 double _dummy_force_double_alignment[RM_SIZE>>1];
62 // Array of Register Mask bits. This array is large enough to cover
63 // all the machine registers and all parameters that need to be passed
64 // on the stack (stack registers) up to some interesting limit. Methods
65 // that need more parameters will NOT be compiled. On Intel, the limit
66 // is something like 90+ parameters.
67 int _A[RM_SIZE];
68 };
69
70 enum {
71 _WordBits = BitsPerInt,
72 _LogWordBits = LogBitsPerInt,
73 _RM_SIZE = RM_SIZE // local constant, imported, then hidden by #undef
74 };
75
76 public:
77 enum { CHUNK_SIZE = RM_SIZE*_WordBits };
78
79 // SlotsPerLong is 2, since slots are 32 bits and longs are 64 bits.
80 // Also, consider the maximum alignment size for a normally allocated
81 // value. Since we allocate register pairs but not register quads (at
82 // present), this alignment is SlotsPerLong (== 2). A normally
83 // aligned allocated register is either a single register, or a pair
84 // of adjacent registers, the lower-numbered being even.
85 // See also is_aligned_Pairs() below, and the padding added before
86 // Matcher::_new_SP to keep allocated pairs aligned properly.
87 // If we ever go to quad-word allocations, SlotsPerQuad will become
88 // the controlling alignment constraint. Note that this alignment
89 // requirement is internal to the allocator, and independent of any
90 // particular platform.
91 enum { SlotsPerLong = 2 };
92
93 // A constructor only used by the ADLC output. All mask fields are filled
94 // in directly. Calls to this look something like RM(1,2,3,4);
95 RegMask(
96 # define BODY(I) int a##I,
97 FORALL_BODY
98 # undef BODY
99 int dummy = 0 ) {
100 # define BODY(I) _A[I] = a##I;
101 FORALL_BODY
102 # undef BODY
103 }
104
105 // Handy copying constructor
106 RegMask( RegMask *rm ) {
107 # define BODY(I) _A[I] = rm->_A[I];
108 FORALL_BODY
109 # undef BODY
110 }
111
112 // Construct an empty mask
113 RegMask( ) { Clear(); }
114
115 // Construct a mask with a single bit
116 RegMask( OptoReg::Name reg ) { Clear(); Insert(reg); }
117
118 // Check for register being in mask
119 int Member( OptoReg::Name reg ) const {
120 assert( reg < CHUNK_SIZE, "" );
121 return _A[reg>>_LogWordBits] & (1<<(reg&(_WordBits-1)));
122 }
123
124 // The last bit in the register mask indicates that the mask should repeat
125 // indefinitely with ONE bits. Returns TRUE if mask is infinite or
126 // unbounded in size. Returns FALSE if mask is finite size.
127 int is_AllStack() const { return _A[RM_SIZE-1] >> (_WordBits-1); }
128
129 // Work around an -xO3 optimization problme in WS6U1. The old way:
130 // void set_AllStack() { _A[RM_SIZE-1] |= (1<<(_WordBits-1)); }
131 // will cause _A[RM_SIZE-1] to be clobbered, not updated when set_AllStack()
132 // follows an Insert() loop, like the one found in init_spill_mask(). Using
133 // Insert() instead works because the index into _A in computed instead of
134 // constant. See bug 4665841.
135 void set_AllStack() { Insert(OptoReg::Name(CHUNK_SIZE-1)); }
136
137 // Test for being a not-empty mask.
138 int is_NotEmpty( ) const {
139 int tmp = 0;
140 # define BODY(I) tmp |= _A[I];
141 FORALL_BODY
142 # undef BODY
143 return tmp;
144 }
145
146 // Find lowest-numbered register from mask, or BAD if mask is empty.
147 OptoReg::Name find_first_elem() const {
148 int base, bits;
149 # define BODY(I) if( (bits = _A[I]) != 0 ) base = I<<_LogWordBits; else
150 FORALL_BODY
151 # undef BODY
152 { base = OptoReg::Bad; bits = 1<<0; }
153 return OptoReg::Name(base + find_lowest_bit(bits));
154 }
155 // Get highest-numbered register from mask, or BAD if mask is empty.
156 OptoReg::Name find_last_elem() const {
157 int base, bits;
158 # define BODY(I) if( (bits = _A[RM_SIZE-1-I]) != 0 ) base = (RM_SIZE-1-I)<<_LogWordBits; else
159 FORALL_BODY
160 # undef BODY
161 { base = OptoReg::Bad; bits = 1<<0; }
162 return OptoReg::Name(base + find_hihghest_bit(bits));
163 }
164
165 // Find the lowest-numbered register pair in the mask. Return the
166 // HIGHEST register number in the pair, or BAD if no pairs.
167 // Assert that the mask contains only bit pairs.
168 OptoReg::Name find_first_pair() const;
169
170 // Clear out partial bits; leave only aligned adjacent bit pairs.
171 void ClearToPairs();
172 // Smear out partial bits; leave only aligned adjacent bit pairs.
173 void SmearToPairs();
174 // Verify that the mask contains only aligned adjacent bit pairs
175 void VerifyPairs() const { assert( is_aligned_Pairs(), "mask is not aligned, adjacent pairs" ); }
176 // Test that the mask contains only aligned adjacent bit pairs
177 bool is_aligned_Pairs() const;
178
179 // mask is a pair of misaligned registers
180 bool is_misaligned_Pair() const { return Size()==2 && !is_aligned_Pairs();}
181 // Test for single register
182 int is_bound1() const;
183 // Test for a single adjacent pair
184 int is_bound2() const;
185
186 // Fast overlap test. Non-zero if any registers in common.
187 int overlap( const RegMask &rm ) const {
188 return
189 # define BODY(I) (_A[I] & rm._A[I]) |
190 FORALL_BODY
191 # undef BODY
192 0 ;
193 }
194
195 // Special test for register pressure based splitting
196 // UP means register only, Register plus stack, or stack only is DOWN
197 bool is_UP() const;
198
199 // Clear a register mask
200 void Clear( ) {
201 # define BODY(I) _A[I] = 0;
202 FORALL_BODY
203 # undef BODY
204 }
205
206 // Fill a register mask with 1's
207 void Set_All( ) {
208 # define BODY(I) _A[I] = -1;
209 FORALL_BODY
210 # undef BODY
211 }
212
213 // Insert register into mask
214 void Insert( OptoReg::Name reg ) {
215 assert( reg < CHUNK_SIZE, "" );
216 _A[reg>>_LogWordBits] |= (1<<(reg&(_WordBits-1)));
217 }
218
219 // Remove register from mask
220 void Remove( OptoReg::Name reg ) {
221 assert( reg < CHUNK_SIZE, "" );
222 _A[reg>>_LogWordBits] &= ~(1<<(reg&(_WordBits-1)));
223 }
224
225 // OR 'rm' into 'this'
226 void OR( const RegMask &rm ) {
227 # define BODY(I) this->_A[I] |= rm._A[I];
228 FORALL_BODY
229 # undef BODY
230 }
231
232 // AND 'rm' into 'this'
233 void AND( const RegMask &rm ) {
234 # define BODY(I) this->_A[I] &= rm._A[I];
235 FORALL_BODY
236 # undef BODY
237 }
238
239 // Subtract 'rm' from 'this'
240 void SUBTRACT( const RegMask &rm ) {
241 # define BODY(I) _A[I] &= ~rm._A[I];
242 FORALL_BODY
243 # undef BODY
244 }
245
246 // Compute size of register mask: number of bits
247 uint Size() const;
248
249 #ifndef PRODUCT
250 void print() const { dump(); }
251 void dump() const; // Print a mask
252 #endif
253
254 static const RegMask Empty; // Common empty mask
255
256 static bool can_represent(OptoReg::Name reg) {
257 // NOTE: -1 in computation reflects the usage of the last
258 // bit of the regmask as an infinite stack flag.
259 return (int)reg < (int)(CHUNK_SIZE-1);
260 }
261 };
262
263 // Do not use this constant directly in client code!
264 #undef RM_SIZE