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()
34 : gv(kUndefined) {
35 }
36
37 Var* gv;
38 };
39
40 vector<string*>* g_symbols;
41 static vector<SymbolData> g_symbol_data;
42
43 Symbol kEmptySym = Symbol(Symbol::IsUninitialized());
44 Symbol kShellSym = Symbol(Symbol::IsUninitialized());
45
Symbol(int v)46 Symbol::Symbol(int v)
47 : v_(v) {
48 }
49
GetGlobalVar() const50 Var* Symbol::GetGlobalVar() const {
51 if (static_cast<size_t>(v_) >= g_symbol_data.size()) {
52 g_symbol_data.resize(v_ + 1);
53 }
54 Var* v = g_symbol_data[v_].gv;
55 if (v->Origin() == VarOrigin::ENVIRONMENT ||
56 v->Origin() == VarOrigin::ENVIRONMENT_OVERRIDE) {
57 Vars::add_used_env_vars(*this);
58 }
59 return v;
60 }
61
SetGlobalVar(Var * v,bool is_override,bool * readonly) const62 void Symbol::SetGlobalVar(Var* v, bool is_override, bool* readonly) const {
63 if (static_cast<size_t>(v_) >= g_symbol_data.size()) {
64 g_symbol_data.resize(v_ + 1);
65 }
66 Var* orig = g_symbol_data[v_].gv;
67 if (orig->ReadOnly()) {
68 if (readonly != nullptr)
69 *readonly = true;
70 else
71 ERROR("*** cannot assign to readonly variable: %s", c_str());
72 return;
73 } else if (readonly != nullptr) {
74 *readonly = false;
75 }
76 if (!is_override &&
77 (orig->Origin() == VarOrigin::OVERRIDE ||
78 orig->Origin() == VarOrigin::ENVIRONMENT_OVERRIDE)) {
79 return;
80 }
81 if (orig->Origin() == VarOrigin::COMMAND_LINE &&
82 v->Origin() == VarOrigin::FILE) {
83 return;
84 }
85 if (orig->Origin() == VarOrigin::AUTOMATIC) {
86 ERROR("overriding automatic variable is not implemented yet");
87 }
88 if (orig->IsDefined())
89 delete orig;
90 g_symbol_data[v_].gv = v;
91 }
92
ScopedGlobalVar(Symbol name,Var * var)93 ScopedGlobalVar::ScopedGlobalVar(Symbol name, Var* var)
94 : name_(name), orig_(NULL) {
95 orig_ = name.GetGlobalVar();
96 g_symbol_data[name_.val()].gv = var;
97 }
98
~ScopedGlobalVar()99 ScopedGlobalVar::~ScopedGlobalVar() {
100 g_symbol_data[name_.val()].gv = orig_;
101 }
102
103 class Symtab {
104 public:
Symtab()105 Symtab() {
106 #ifdef ENABLE_TID_CHECK
107 tid_ = pthread_self();
108 #endif
109
110 CHECK(g_symbols == NULL);
111 g_symbols = &symbols_;
112
113 Symbol s = InternImpl("");
114 CHECK(s.v_ == 0);
115 CHECK(Intern("") == s);
116 char b[2];
117 b[1] = 0;
118 for (int i = 1; i < 256; i++) {
119 b[0] = i;
120 s = InternImpl(b);
121 CHECK(s.val() == i);
122 }
123
124 kEmptySym = Intern("");
125 kShellSym = Intern("SHELL");
126 }
127
~Symtab()128 ~Symtab() {
129 LOG_STAT("%zu symbols", symbols_.size());
130 for (string* s : symbols_)
131 delete s;
132 }
133
InternImpl(StringPiece s)134 Symbol InternImpl(StringPiece s) {
135 auto found = symtab_.find(s);
136 if (found != symtab_.end()) {
137 return found->second;
138 }
139 symbols_.push_back(new string(s.data(), s.size()));
140 Symbol sym = Symbol(symtab_.size());
141 bool ok = symtab_.emplace(*symbols_.back(), sym).second;
142 CHECK(ok);
143 return sym;
144 }
145
Intern(StringPiece s)146 Symbol Intern(StringPiece s) {
147 #ifdef ENABLE_TID_CHECK
148 if (tid_ != pthread_self())
149 abort();
150 #endif
151
152 if (s.size() <= 1) {
153 return Symbol(s.empty() ? 0 : (unsigned char)s[0]);
154 }
155 return InternImpl(s);
156 }
157
158 private:
159 unordered_map<StringPiece, Symbol> symtab_;
160 vector<string*> symbols_;
161 #ifdef ENABLE_TID_CHECK
162 pthread_t tid_;
163 #endif
164 };
165
166 static Symtab* g_symtab;
167
InitSymtab()168 void InitSymtab() {
169 g_symtab = new Symtab;
170 }
171
QuitSymtab()172 void QuitSymtab() {
173 delete g_symtab;
174 }
175
Intern(StringPiece s)176 Symbol Intern(StringPiece s) {
177 return g_symtab->Intern(s);
178 }
179
JoinSymbols(const vector<Symbol> & syms,const char * sep)180 string JoinSymbols(const vector<Symbol>& syms, const char* sep) {
181 vector<string> strs;
182 for (Symbol s : syms) {
183 strs.push_back(s.str());
184 }
185 return JoinStrings(strs, sep);
186 }
187