1 //===- lib/MC/MCSymbolELF.cpp ---------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "llvm/MC/MCSymbolELF.h"
10 #include "llvm/BinaryFormat/ELF.h"
11 
12 namespace llvm {
13 
14 namespace {
15 enum {
16   // Shift value for STT_* flags. 7 possible values. 3 bits.
17   ELF_STT_Shift = 0,
18 
19   // Shift value for STB_* flags. 4 possible values, 2 bits.
20   ELF_STB_Shift = 3,
21 
22   // Shift value for STV_* flags. 4 possible values, 2 bits.
23   ELF_STV_Shift = 5,
24 
25   // Shift value for STO_* flags. 3 bits. All the values are between 0x20 and
26   // 0xe0, so we shift right by 5 before storing.
27   ELF_STO_Shift = 7,
28 
29   // One bit.
30   ELF_IsSignature_Shift = 10,
31 
32   // One bit.
33   ELF_WeakrefUsedInReloc_Shift = 11,
34 
35   // One bit.
36   ELF_BindingSet_Shift = 12,
37 
38   // One bit.
39   ELF_IsMemoryTagged_Shift = 13,
40 };
41 }
42 
43 void MCSymbolELF::setBinding(unsigned Binding) const {
44   setIsBindingSet();
45   unsigned Val;
46   switch (Binding) {
47   default:
48     llvm_unreachable("Unsupported Binding");
49   case ELF::STB_LOCAL:
50     Val = 0;
51     break;
52   case ELF::STB_GLOBAL:
53     Val = 1;
54     break;
55   case ELF::STB_WEAK:
56     Val = 2;
57     break;
58   case ELF::STB_GNU_UNIQUE:
59     Val = 3;
60     break;
61   }
62   uint32_t OtherFlags = getFlags() & ~(0x3 << ELF_STB_Shift);
63   setFlags(OtherFlags | (Val << ELF_STB_Shift));
64 }
65 
66 unsigned MCSymbolELF::getBinding() const {
67   if (isBindingSet()) {
68     uint32_t Val = (Flags >> ELF_STB_Shift) & 3;
69     switch (Val) {
70     default:
71       llvm_unreachable("Invalid value");
72     case 0:
73       return ELF::STB_LOCAL;
74     case 1:
75       return ELF::STB_GLOBAL;
76     case 2:
77       return ELF::STB_WEAK;
78     case 3:
79       return ELF::STB_GNU_UNIQUE;
80     }
81   }
82 
83   if (isDefined())
84     return ELF::STB_LOCAL;
85   if (isUsedInReloc())
86     return ELF::STB_GLOBAL;
87   if (isWeakrefUsedInReloc())
88     return ELF::STB_WEAK;
89   if (isSignature())
90     return ELF::STB_LOCAL;
91   return ELF::STB_GLOBAL;
92 }
93 
94 void MCSymbolELF::setType(unsigned Type) const {
95   unsigned Val;
96   switch (Type) {
97   default:
98     llvm_unreachable("Unsupported Binding");
99   case ELF::STT_NOTYPE:
100     Val = 0;
101     break;
102   case ELF::STT_OBJECT:
103     Val = 1;
104     break;
105   case ELF::STT_FUNC:
106     Val = 2;
107     break;
108   case ELF::STT_SECTION:
109     Val = 3;
110     break;
111   case ELF::STT_COMMON:
112     Val = 4;
113     break;
114   case ELF::STT_TLS:
115     Val = 5;
116     break;
117   case ELF::STT_GNU_IFUNC:
118     Val = 6;
119     break;
120   }
121   uint32_t OtherFlags = getFlags() & ~(0x7 << ELF_STT_Shift);
122   setFlags(OtherFlags | (Val << ELF_STT_Shift));
123 }
124 
125 unsigned MCSymbolELF::getType() const {
126   uint32_t Val = (Flags >> ELF_STT_Shift) & 7;
127   switch (Val) {
128   default:
129     llvm_unreachable("Invalid value");
130   case 0:
131     return ELF::STT_NOTYPE;
132   case 1:
133     return ELF::STT_OBJECT;
134   case 2:
135     return ELF::STT_FUNC;
136   case 3:
137     return ELF::STT_SECTION;
138   case 4:
139     return ELF::STT_COMMON;
140   case 5:
141     return ELF::STT_TLS;
142   case 6:
143     return ELF::STT_GNU_IFUNC;
144   }
145 }
146 
147 void MCSymbolELF::setVisibility(unsigned Visibility) {
148   assert(Visibility == ELF::STV_DEFAULT || Visibility == ELF::STV_INTERNAL ||
149          Visibility == ELF::STV_HIDDEN || Visibility == ELF::STV_PROTECTED);
150 
151   uint32_t OtherFlags = getFlags() & ~(0x3 << ELF_STV_Shift);
152   setFlags(OtherFlags | (Visibility << ELF_STV_Shift));
153 }
154 
155 unsigned MCSymbolELF::getVisibility() const {
156   unsigned Visibility = (Flags >> ELF_STV_Shift) & 3;
157   return Visibility;
158 }
159 
160 void MCSymbolELF::setOther(unsigned Other) {
161   assert((Other & 0x1f) == 0);
162   Other >>= 5;
163   assert(Other <= 0x7);
164   uint32_t OtherFlags = getFlags() & ~(0x7 << ELF_STO_Shift);
165   setFlags(OtherFlags | (Other << ELF_STO_Shift));
166 }
167 
168 unsigned MCSymbolELF::getOther() const {
169   unsigned Other = (Flags >> ELF_STO_Shift) & 7;
170   return Other << 5;
171 }
172 
173 void MCSymbolELF::setIsWeakrefUsedInReloc() const {
174   uint32_t OtherFlags = getFlags() & ~(0x1 << ELF_WeakrefUsedInReloc_Shift);
175   setFlags(OtherFlags | (1 << ELF_WeakrefUsedInReloc_Shift));
176 }
177 
178 bool MCSymbolELF::isWeakrefUsedInReloc() const {
179   return getFlags() & (0x1 << ELF_WeakrefUsedInReloc_Shift);
180 }
181 
182 void MCSymbolELF::setIsSignature() const {
183   uint32_t OtherFlags = getFlags() & ~(0x1 << ELF_IsSignature_Shift);
184   setFlags(OtherFlags | (1 << ELF_IsSignature_Shift));
185 }
186 
187 bool MCSymbolELF::isSignature() const {
188   return getFlags() & (0x1 << ELF_IsSignature_Shift);
189 }
190 
191 void MCSymbolELF::setIsBindingSet() const {
192   uint32_t OtherFlags = getFlags() & ~(0x1 << ELF_BindingSet_Shift);
193   setFlags(OtherFlags | (1 << ELF_BindingSet_Shift));
194 }
195 
196 bool MCSymbolELF::isBindingSet() const {
197   return getFlags() & (0x1 << ELF_BindingSet_Shift);
198 }
199 
200 bool MCSymbolELF::isMemtag() const {
201   return getFlags() & (0x1 << ELF_IsMemoryTagged_Shift);
202 }
203 
204 void MCSymbolELF::setMemtag(bool Tagged) {
205   uint32_t OtherFlags = getFlags() & ~(1 << ELF_IsMemoryTagged_Shift);
206   if (Tagged)
207     setFlags(OtherFlags | (1 << ELF_IsMemoryTagged_Shift));
208   else
209     setFlags(OtherFlags);
210 }
211 }
212