1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
|
// Copyright 2012 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef V8_CODEGEN_REGISTER_H_
#define V8_CODEGEN_REGISTER_H_
#include "src/base/bounds.h"
#include "src/codegen/reglist.h"
namespace v8 {
namespace internal {
// Base type for CPU Registers.
//
// 1) We would prefer to use an enum for registers, but enum values are
// assignment-compatible with int, which has caused code-generation bugs.
//
// 2) By not using an enum, we are possibly preventing the compiler from
// doing certain constant folds, which may significantly reduce the
// code generated for some assembly instructions (because they boil down
// to a few constants). If this is a problem, we could change the code
// such that we use an enum in optimized mode, and the class in debug
// mode. This way we get the compile-time error checking in debug mode
// and best performance in optimized code.
template <typename SubType, int kAfterLastRegister>
class RegisterBase {
public:
static constexpr int kCode_no_reg = -1;
static constexpr int kNumRegisters = kAfterLastRegister;
static constexpr SubType no_reg() { return SubType{kCode_no_reg}; }
static constexpr SubType from_code(int code) {
CONSTEXPR_DCHECK(base::IsInRange(code, 0, kNumRegisters - 1));
return SubType{code};
}
template <typename... Register>
static constexpr RegList ListOf(Register... regs) {
return CombineRegLists(regs.bit()...);
}
constexpr bool is_valid() const { return reg_code_ != kCode_no_reg; }
constexpr int code() const {
CONSTEXPR_DCHECK(is_valid());
return reg_code_;
}
constexpr RegList bit() const {
return is_valid() ? RegList{1} << code() : RegList{};
}
inline constexpr bool operator==(SubType other) const {
return reg_code_ == other.reg_code_;
}
inline constexpr bool operator!=(SubType other) const {
return reg_code_ != other.reg_code_;
}
// Used to print the name of some special registers.
static const char* GetSpecialRegisterName(int code) { return "UNKNOWN"; }
protected:
explicit constexpr RegisterBase(int code) : reg_code_(code) {}
private:
int reg_code_;
};
// Whether padding is needed for the given stack argument count.
bool ShouldPadArguments(int argument_count);
template <typename RegType,
typename = decltype(RegisterName(std::declval<RegType>()))>
inline std::ostream& operator<<(std::ostream& os, RegType reg) {
return os << RegisterName(reg);
}
// Helper macros to define a {RegisterName} method based on a macro list
// containing all names.
#define DEFINE_REGISTER_NAMES_NAME(name) #name,
#define DEFINE_REGISTER_NAMES(RegType, LIST) \
inline const char* RegisterName(RegType reg) { \
static constexpr const char* Names[] = {LIST(DEFINE_REGISTER_NAMES_NAME)}; \
STATIC_ASSERT(arraysize(Names) == RegType::kNumRegisters); \
return reg.is_valid() ? Names[reg.code()] : "invalid"; \
}
} // namespace internal
} // namespace v8
#endif // V8_CODEGEN_REGISTER_H_
|
