1 // Copyright 2015 Google Inc. All rights reserved
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 // http://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14
15 // +build ignore
16
17 //#define ENABLE_TID_CHECK
18
19 #include "symtab.h"
20
21 #ifdef ENABLE_TID_CHECK
22 #include <pthread.h>
23 #endif
24 #include <string.h>
25
26 #include <unordered_map>
27
28 #include "log.h"
29 #include "strutil.h"
30 #include "var.h"
31
32 struct SymbolData {
SymbolDataSymbolData33 SymbolData() : gv(kUndefined) {}
34
35 Var* gv;
36 };
37
38 vector<string*>* g_symbols;
39 static vector<SymbolData> g_symbol_data;
40
41 Symbol kEmptySym = Symbol(Symbol::IsUninitialized());
42 Symbol kShellSym = Symbol(Symbol::IsUninitialized());
43
Symbol(int v)44 Symbol::Symbol(int v) : v_(v) {}
45
PeekGlobalVar() const46 Var* Symbol::PeekGlobalVar() const {
47 if (static_cast<size_t>(v_) >= g_symbol_data.size()) {
48 return kUndefined;
49 }
50 return g_symbol_data[v_].gv;
51 }
52
GetGlobalVar() const53 Var* Symbol::GetGlobalVar() const {
54 if (static_cast<size_t>(v_) >= g_symbol_data.size()) {
55 g_symbol_data.resize(v_ + 1);
56 }
57 Var* v = g_symbol_data[v_].gv;
58 if (v->Origin() == VarOrigin::ENVIRONMENT ||
59 v->Origin() == VarOrigin::ENVIRONMENT_OVERRIDE) {
60 Vars::add_used_env_vars(*this);
61 }
62 return v;
63 }
64
SetGlobalVar(Var * v,bool is_override,bool * readonly) const65 void Symbol::SetGlobalVar(Var* v, bool is_override, bool* readonly) const {
66 if (static_cast<size_t>(v_) >= g_symbol_data.size()) {
67 g_symbol_data.resize(v_ + 1);
68 }
69 Var* orig = g_symbol_data[v_].gv;
70 if (orig->ReadOnly()) {
71 if (readonly != nullptr)
72 *readonly = true;
73 else
74 ERROR("*** cannot assign to readonly variable: %s", c_str());
75 return;
76 } else if (readonly != nullptr) {
77 *readonly = false;
78 }
79 if (!is_override && (orig->Origin() == VarOrigin::OVERRIDE ||
80 orig->Origin() == VarOrigin::ENVIRONMENT_OVERRIDE)) {
81 return;
82 }
83 if (orig->Origin() == VarOrigin::COMMAND_LINE &&
84 v->Origin() == VarOrigin::FILE) {
85 return;
86 }
87 if (orig->Origin() == VarOrigin::AUTOMATIC) {
88 ERROR("overriding automatic variable is not implemented yet");
89 }
90 if (orig->IsDefined())
91 delete orig;
92 g_symbol_data[v_].gv = v;
93 }
94
ScopedGlobalVar(Symbol name,Var * var)95 ScopedGlobalVar::ScopedGlobalVar(Symbol name, Var* var)
96 : name_(name), orig_(NULL) {
97 orig_ = name.GetGlobalVar();
98 g_symbol_data[name_.val()].gv = var;
99 }
100
~ScopedGlobalVar()101 ScopedGlobalVar::~ScopedGlobalVar() {
102 g_symbol_data[name_.val()].gv = orig_;
103 }
104
105 class Symtab {
106 public:
Symtab()107 Symtab() {
108 #ifdef ENABLE_TID_CHECK
109 tid_ = pthread_self();
110 #endif
111
112 CHECK(g_symbols == NULL);
113 g_symbols = &symbols_;
114
115 Symbol s = InternImpl("");
116 CHECK(s.v_ == 0);
117 CHECK(Intern("") == s);
118 char b[2];
119 b[1] = 0;
120 for (int i = 1; i < 256; i++) {
121 b[0] = i;
122 s = InternImpl(b);
123 CHECK(s.val() == i);
124 }
125
126 kEmptySym = Intern("");
127 kShellSym = Intern("SHELL");
128 }
129
~Symtab()130 ~Symtab() {
131 LOG_STAT("%zu symbols", symbols_.size());
132 for (string* s : symbols_)
133 delete s;
134 }
135
InternImpl(StringPiece s)136 Symbol InternImpl(StringPiece s) {
137 auto found = symtab_.find(s);
138 if (found != symtab_.end()) {
139 return found->second;
140 }
141 symbols_.push_back(new string(s.data(), s.size()));
142 Symbol sym = Symbol(symtab_.size());
143 bool ok = symtab_.emplace(*symbols_.back(), sym).second;
144 CHECK(ok);
145 return sym;
146 }
147
Intern(StringPiece s)148 Symbol Intern(StringPiece s) {
149 #ifdef ENABLE_TID_CHECK
150 if (tid_ != pthread_self())
151 abort();
152 #endif
153
154 if (s.size() <= 1) {
155 return Symbol(s.empty() ? 0 : (unsigned char)s[0]);
156 }
157 return InternImpl(s);
158 }
159
160 private:
161 unordered_map<StringPiece, Symbol> symtab_;
162 vector<string*> symbols_;
163 #ifdef ENABLE_TID_CHECK
164 pthread_t tid_;
165 #endif
166 };
167
168 static Symtab* g_symtab;
169
InitSymtab()170 void InitSymtab() {
171 g_symtab = new Symtab;
172 }
173
QuitSymtab()174 void QuitSymtab() {
175 delete g_symtab;
176 }
177
Intern(StringPiece s)178 Symbol Intern(StringPiece s) {
179 return g_symtab->Intern(s);
180 }
181
JoinSymbols(const vector<Symbol> & syms,const char * sep)182 string JoinSymbols(const vector<Symbol>& syms, const char* sep) {
183 vector<string> strs;
184 for (Symbol s : syms) {
185 strs.push_back(s.str());
186 }
187 return JoinStrings(strs, sep);
188 }
189