1 #ifdef USE_PRAGMA_IDENT_HDR
2 #pragma ident "@(#)vmreg.hpp 1.37 07/05/05 17:05:22 JVM"
3 #endif
4 /*
5 * Copyright 1998-2008 Sun Microsystems, Inc. All Rights Reserved.
6 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
7 *
8 * This code is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License version 2 only, as
10 * published by the Free Software Foundation.
11 *
12 * This code is distributed in the hope that it will be useful, but WITHOUT
13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 * version 2 for more details (a copy is included in the LICENSE file that
16 * accompanied this code).
17 *
18 * You should have received a copy of the GNU General Public License version
19 * 2 along with this work; if not, write to the Free Software Foundation,
20 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
21 *
22 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
23 * CA 95054 USA or visit www.sun.com if you need additional information or
24 * have any questions.
25 *
26 */
27
28 //------------------------------VMReg------------------------------------------
29 // The VM uses 'unwarped' stack slots; the compiler uses 'warped' stack slots.
30 // Register numbers below VMRegImpl::stack0 are the same for both. Register
31 // numbers above stack0 are either warped (in the compiler) or unwarped
32 // (in the VM). Unwarped numbers represent stack indices, offsets from
33 // the current stack pointer. Warped numbers are required during compilation
34 // when we do not yet know how big the frame will be.
35
36 class VMRegImpl;
37 typedef VMRegImpl* VMReg;
38
39 class VMRegImpl {
40 // friend class OopMap;
41 friend class VMStructs;
42 friend class OptoReg;
43 // friend class Location;
44 private:
45 enum {
46 BAD = -1
47 };
48
49
50
51 static VMReg stack0;
52 // Names for registers
53 static const char *regName[];
54 static const int register_count;
55
56
57 public:
58
59 static VMReg as_VMReg(int val, bool bad_ok = false) { assert(val > BAD || bad_ok, "invalid"); return (VMReg) (intptr_t) val; }
60
61 const char* name() {
62 if (is_reg()) {
63 return regName[value()];
64 } else if (!is_valid()) {
65 return "BAD";
66 } else {
67 // shouldn't really be called with stack
68 return "STACKED REG";
69 }
70 }
71 static VMReg Bad() { return (VMReg) (intptr_t) BAD; }
72 bool is_valid() const { return ((intptr_t) this) != BAD; }
73 bool is_stack() const { return (intptr_t) this >= (intptr_t) stack0; }
74 bool is_reg() const { return is_valid() && !is_stack(); }
75
76 // A concrete register is a value that returns true for is_reg() and is
77 // also a register you could use in the assembler. On machines with
78 // 64bit registers only one half of the VMReg (and OptoReg) is considered
79 // concrete.
80 bool is_concrete();
81
82 // VMRegs are 4 bytes wide on all platforms
83 static const int stack_slot_size;
84 static const int slots_per_word;
85
86
87 // This really ought to check that the register is "real" in the sense that
88 // we don't try and get the VMReg number of a physical register that doesn't
89 // have an expressible part. That would be pd specific code
90 VMReg next() {
91 assert((is_reg() && value() < stack0->value() - 1) || is_stack(), "must be");
92 return (VMReg)(intptr_t)(value() + 1);
93 }
94 VMReg prev() {
95 assert((is_stack() && value() > stack0->value()) || (is_reg() && value() != 0), "must be");
96 return (VMReg)(intptr_t)(value() - 1);
97 }
98
99
100 intptr_t value() const {return (intptr_t) this; }
101
102 void print_on(outputStream* st) const;
103 void print() const { print_on(tty); }
104
105 // bias a stack slot.
106 // Typically used to adjust a virtual frame slots by amounts that are offset by
107 // amounts that are part of the native abi. The VMReg must be a stack slot
108 // and the result must be also.
109
110 VMReg bias(int offset) {
111 assert(is_stack(), "must be");
112 // VMReg res = VMRegImpl::as_VMReg(value() + offset);
113 VMReg res = stack2reg(reg2stack() + offset);
114 assert(res->is_stack(), "must be");
115 return res;
116 }
117
118 // Convert register numbers to stack slots and vice versa
119 static VMReg stack2reg( int idx ) {
120 return (VMReg) (intptr_t) (stack0->value() + idx);
121 }
122
123 uintptr_t reg2stack() {
124 assert( is_stack(), "Not a stack-based register" );
125 return value() - stack0->value();
126 }
127
128 static void set_regName();
129
130 #include "incls/_vmreg_pd.hpp.incl"
131
132 };
133
134 //---------------------------VMRegPair-------------------------------------------
135 // Pairs of 32-bit registers for arguments.
136 // SharedRuntime::java_calling_convention will overwrite the structs with
137 // the calling convention's registers. VMRegImpl::Bad is returned for any
138 // unused 32-bit register. This happens for the unused high half of Int
139 // arguments, or for 32-bit pointers or for longs in the 32-bit sparc build
140 // (which are passed to natives in low 32-bits of e.g. O0/O1 and the high
141 // 32-bits of O0/O1 are set to VMRegImpl::Bad). Longs in one register & doubles
142 // always return a high and a low register, as do 64-bit pointers.
143 //
144 class VMRegPair {
145 private:
146 VMReg _second;
147 VMReg _first;
148 public:
149 void set_bad ( ) { _second=VMRegImpl::Bad(); _first=VMRegImpl::Bad(); }
150 void set1 ( VMReg v ) { _second=VMRegImpl::Bad(); _first=v; }
151 void set2 ( VMReg v ) { _second=v->next(); _first=v; }
152 void set_pair( VMReg second, VMReg first ) { _second= second; _first= first; }
153 void set_ptr ( VMReg ptr ) {
154 #ifdef _LP64
155 _second = ptr->next();
156 #else
157 _second = VMRegImpl::Bad();
158 #endif
159 _first = ptr;
160 }
161 // Return true if single register, even if the pair is really just adjacent stack slots
162 bool is_single_reg() const {
163 return (_first->is_valid()) && (_first->value() + 1 == _second->value());
164 }
165
166 // Return true if single stack based "register" where the slot alignment matches input alignment
167 bool is_adjacent_on_stack(int alignment) const {
168 return (_first->is_stack() && (_first->value() + 1 == _second->value()) && ((_first->value() & (alignment-1)) == 0));
169 }
170
171 // Return true if single stack based "register" where the slot alignment matches input alignment
172 bool is_adjacent_aligned_on_stack(int alignment) const {
173 return (_first->is_stack() && (_first->value() + 1 == _second->value()) && ((_first->value() & (alignment-1)) == 0));
174 }
175
176 // Return true if single register but adjacent stack slots do not count
177 bool is_single_phys_reg() const {
178 return (_first->is_reg() && (_first->value() + 1 == _second->value()));
179 }
180
181 VMReg second() const { return _second; }
182 VMReg first() const { return _first; }
183 VMRegPair(VMReg s, VMReg f) { _second = s; _first = f; }
184 VMRegPair(VMReg f) { _second = VMRegImpl::Bad(); _first = f; }
185 VMRegPair() { _second = VMRegImpl::Bad(); _first = VMRegImpl::Bad(); }
186 };