1 // Copyright 2009 the V8 project authors. All rights reserved.
2 // Redistribution and use in source and binary forms, with or without
3 // modification, are permitted provided that the following conditions are
4 // met:
5 //
6 // * Redistributions of source code must retain the above copyright
7 // notice, this list of conditions and the following disclaimer.
8 // * Redistributions in binary form must reproduce the above
9 // copyright notice, this list of conditions and the following
10 // disclaimer in the documentation and/or other materials provided
11 // with the distribution.
12 // * Neither the name of Google Inc. nor the names of its
13 // contributors may be used to endorse or promote products derived
14 // from this software without specific prior written permission.
15 //
16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27
28 #include "v8.h"
29
30 #include "codegen-inl.h"
31 #include "register-allocator-inl.h"
32
33 namespace v8 {
34 namespace internal {
35
36 // -------------------------------------------------------------------------
37 // Result implementation.
38
39
Result(Register reg,NumberInfo::Type info)40 Result::Result(Register reg, NumberInfo::Type info) {
41 ASSERT(reg.is_valid() && !RegisterAllocator::IsReserved(reg));
42 CodeGeneratorScope::Current()->allocator()->Use(reg);
43 value_ = TypeField::encode(REGISTER)
44 | NumberInfoField::encode(info)
45 | DataField::encode(reg.code_);
46 }
47
48
ConstantList()49 Result::ZoneObjectList* Result::ConstantList() {
50 static ZoneObjectList list(10);
51 return &list;
52 }
53
54
number_info()55 NumberInfo::Type Result::number_info() {
56 ASSERT(is_valid());
57 if (!is_constant()) return NumberInfoField::decode(value_);
58 Handle<Object> value = handle();
59 if (value->IsSmi()) return NumberInfo::kSmi;
60 if (value->IsHeapNumber()) return NumberInfo::kHeapNumber;
61 return NumberInfo::kUnknown;
62 }
63
64
set_number_info(NumberInfo::Type info)65 void Result::set_number_info(NumberInfo::Type info) {
66 ASSERT(is_valid());
67 value_ = value_ & ~NumberInfoField::mask();
68 value_ = value_ | NumberInfoField::encode(info);
69 }
70
71
72 // -------------------------------------------------------------------------
73 // RegisterAllocator implementation.
74
75
AllocateWithoutSpilling()76 Result RegisterAllocator::AllocateWithoutSpilling() {
77 // Return the first free register, if any.
78 int num = registers_.ScanForFreeRegister();
79 if (num == RegisterAllocator::kInvalidRegister) {
80 return Result();
81 }
82 return Result(RegisterAllocator::ToRegister(num));
83 }
84
85
Allocate()86 Result RegisterAllocator::Allocate() {
87 Result result = AllocateWithoutSpilling();
88 if (!result.is_valid()) {
89 // Ask the current frame to spill a register.
90 ASSERT(cgen_->has_valid_frame());
91 Register free_reg = cgen_->frame()->SpillAnyRegister();
92 if (free_reg.is_valid()) {
93 ASSERT(!is_used(free_reg));
94 return Result(free_reg);
95 }
96 }
97 return result;
98 }
99
100
Allocate(Register target)101 Result RegisterAllocator::Allocate(Register target) {
102 // If the target is not referenced, it can simply be allocated.
103 if (!is_used(target)) {
104 return Result(target);
105 }
106 // If the target is only referenced in the frame, it can be spilled and
107 // then allocated.
108 ASSERT(cgen_->has_valid_frame());
109 if (cgen_->frame()->is_used(target) && count(target) == 1) {
110 cgen_->frame()->Spill(target);
111 ASSERT(!is_used(target));
112 return Result(target);
113 }
114 // Otherwise (if it's referenced outside the frame) we cannot allocate it.
115 return Result();
116 }
117
118
119 } } // namespace v8::internal
120