1 //===- ErrorHandler.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 "lld/Common/ErrorHandler.h"
10 
11 #include "llvm/Support/Parallel.h"
12 
13 #include "llvm/ADT/Twine.h"
14 #include "llvm/IR/DiagnosticInfo.h"
15 #include "llvm/IR/DiagnosticPrinter.h"
16 #include "llvm/Support/CrashRecoveryContext.h"
17 #include "llvm/Support/ManagedStatic.h"
18 #include "llvm/Support/Process.h"
19 #include "llvm/Support/Program.h"
20 #include "llvm/Support/raw_ostream.h"
21 #include <mutex>
22 #include <regex>
23 
24 using namespace llvm;
25 using namespace lld;
26 
27 // The functions defined in this file can be called from multiple threads,
28 // but lld::outs() or lld::errs() are not thread-safe. We protect them using a
29 // mutex.
30 static std::mutex mu;
31 
32 // We want to separate multi-line messages with a newline. `sep` is "\n"
33 // if the last messages was multi-line. Otherwise "".
34 static StringRef sep;
35 
36 static StringRef getSeparator(const Twine &msg) {
37   if (StringRef(msg.str()).contains('\n'))
38     return "\n";
39   return "";
40 }
41 
42 raw_ostream *lld::stdoutOS;
43 raw_ostream *lld::stderrOS;
44 
45 ErrorHandler &lld::errorHandler() {
46   static ErrorHandler handler;
47   return handler;
48 }
49 
50 raw_ostream &lld::outs() {
51   if (errorHandler().disableOutput)
52     return llvm::nulls();
53   return stdoutOS ? *stdoutOS : llvm::outs();
54 }
55 
56 raw_ostream &lld::errs() {
57   if (errorHandler().disableOutput)
58     return llvm::nulls();
59   return stderrOS ? *stderrOS : llvm::errs();
60 }
61 
62 void lld::exitLld(int val) {
63   // Delete any temporary file, while keeping the memory mapping open.
64   if (errorHandler().outputBuffer)
65     errorHandler().outputBuffer->discard();
66 
67   // Dealloc/destroy ManagedStatic variables before calling _exit().
68   // In an LTO build, allows us to get the output of -time-passes.
69   // Ensures that the thread pool for the parallel algorithms is stopped to
70   // avoid intermittent crashes on Windows when exiting.
71   if (!CrashRecoveryContext::GetCurrent())
72     llvm_shutdown();
73 
74   {
75     std::lock_guard<std::mutex> lock(mu);
76     lld::outs().flush();
77     lld::errs().flush();
78   }
79   llvm::sys::Process::Exit(val);
80 }
81 
82 void lld::diagnosticHandler(const DiagnosticInfo &di) {
83   SmallString<128> s;
84   raw_svector_ostream os(s);
85   DiagnosticPrinterRawOStream dp(os);
86   di.print(dp);
87   switch (di.getSeverity()) {
88   case DS_Error:
89     error(s);
90     break;
91   case DS_Warning:
92     warn(s);
93     break;
94   case DS_Remark:
95   case DS_Note:
96     message(s);
97     break;
98   }
99 }
100 
101 void lld::checkError(Error e) {
102   handleAllErrors(std::move(e),
103                   [&](ErrorInfoBase &eib) { error(eib.message()); });
104 }
105 
106 // This is for --vs-diagnostics.
107 //
108 // Normally, lld's error message starts with argv[0]. Therefore, it usually
109 // looks like this:
110 //
111 //   ld.lld: error: ...
112 //
113 // This error message style is unfortunately unfriendly to Visual Studio
114 // IDE. VS interprets the first word of the first line as an error location
115 // and make it clickable, thus "ld.lld" in the above message would become a
116 // clickable text. When you click it, VS opens "ld.lld" executable file with
117 // a binary editor.
118 //
119 // As a workaround, we print out an error location instead of "ld.lld" if
120 // lld is running in VS diagnostics mode. As a result, error message will
121 // look like this:
122 //
123 //   src/foo.c(35): error: ...
124 //
125 // This function returns an error location string. An error location is
126 // extracted from an error message using regexps.
127 std::string ErrorHandler::getLocation(const Twine &msg) {
128   if (!vsDiagnostics)
129     return std::string(logName);
130 
131   static std::regex regexes[] = {
132       std::regex(
133           R"(^undefined (?:\S+ )?symbol:.*\n)"
134           R"(>>> referenced by .+\((\S+):(\d+)\))"),
135       std::regex(
136           R"(^undefined (?:\S+ )?symbol:.*\n>>> referenced by (\S+):(\d+))"),
137       std::regex(R"(^undefined symbol:.*\n>>> referenced by (.*):)"),
138       std::regex(
139           R"(^duplicate symbol: .*\n>>> defined in (\S+)\n>>> defined in.*)"),
140       std::regex(
141           R"(^duplicate symbol: .*\n>>> defined at .+\((\S+):(\d+)\))"),
142       std::regex(R"(^duplicate symbol: .*\n>>> defined at (\S+):(\d+))"),
143       std::regex(
144           R"(.*\n>>> defined in .*\n>>> referenced by .+\((\S+):(\d+)\))"),
145       std::regex(R"(.*\n>>> defined in .*\n>>> referenced by (\S+):(\d+))"),
146       std::regex(R"((\S+):(\d+): unclosed quote)"),
147   };
148 
149   std::string str = msg.str();
150   for (std::regex &re : regexes) {
151     std::smatch m;
152     if (!std::regex_search(str, m, re))
153       continue;
154 
155     assert(m.size() == 2 || m.size() == 3);
156     if (m.size() == 2)
157       return m.str(1);
158     return m.str(1) + "(" + m.str(2) + ")";
159   }
160 
161   return std::string(logName);
162 }
163 
164 void ErrorHandler::log(const Twine &msg) {
165   if (!verbose || disableOutput)
166     return;
167   std::lock_guard<std::mutex> lock(mu);
168   lld::errs() << logName << ": " << msg << "\n";
169 }
170 
171 void ErrorHandler::message(const Twine &msg) {
172   if (disableOutput)
173     return;
174   std::lock_guard<std::mutex> lock(mu);
175   lld::outs() << msg << "\n";
176   lld::outs().flush();
177 }
178 
179 void ErrorHandler::warn(const Twine &msg) {
180   if (fatalWarnings) {
181     error(msg);
182     return;
183   }
184 
185   std::lock_guard<std::mutex> lock(mu);
186   lld::errs() << sep << getLocation(msg) << ": " << Colors::MAGENTA
187               << "warning: " << Colors::RESET << msg << "\n";
188   sep = getSeparator(msg);
189 }
190 
191 void ErrorHandler::error(const Twine &msg) {
192   // If Visual Studio-style error message mode is enabled,
193   // this particular error is printed out as two errors.
194   if (vsDiagnostics) {
195     static std::regex re(R"(^(duplicate symbol: .*))"
196                          R"((\n>>> defined at \S+:\d+.*\n>>>.*))"
197                          R"((\n>>> defined at \S+:\d+.*\n>>>.*))");
198     std::string str = msg.str();
199     std::smatch m;
200 
201     if (std::regex_match(str, m, re)) {
202       error(m.str(1) + m.str(2));
203       error(m.str(1) + m.str(3));
204       return;
205     }
206   }
207 
208   bool exit = false;
209   {
210     std::lock_guard<std::mutex> lock(mu);
211 
212     if (errorLimit == 0 || errorCount < errorLimit) {
213       lld::errs() << sep << getLocation(msg) << ": " << Colors::RED
214                   << "error: " << Colors::RESET << msg << "\n";
215     } else if (errorCount == errorLimit) {
216       lld::errs() << sep << getLocation(msg) << ": " << Colors::RED
217                   << "error: " << Colors::RESET << errorLimitExceededMsg
218                   << "\n";
219       exit = exitEarly;
220     }
221 
222     sep = getSeparator(msg);
223     ++errorCount;
224   }
225 
226   if (exit)
227     exitLld(1);
228 }
229 
230 void ErrorHandler::error(const Twine &msg, ErrorTag tag,
231                          ArrayRef<StringRef> args) {
232   if (errorHandlingScript.empty()) {
233     error(msg);
234     return;
235   }
236   SmallVector<StringRef, 4> scriptArgs;
237   scriptArgs.push_back(errorHandlingScript);
238   switch (tag) {
239   case ErrorTag::LibNotFound:
240     scriptArgs.push_back("missing-lib");
241     break;
242   case ErrorTag::SymbolNotFound:
243     scriptArgs.push_back("undefined-symbol");
244     break;
245   }
246   scriptArgs.insert(scriptArgs.end(), args.begin(), args.end());
247   int res = llvm::sys::ExecuteAndWait(errorHandlingScript, scriptArgs);
248   if (res == 0) {
249     return error(msg);
250   } else {
251     // Temporarily disable error limit to make sure the two calls to error(...)
252     // only count as one.
253     uint64_t currentErrorLimit = errorLimit;
254     errorLimit = 0;
255     error(msg);
256     errorLimit = currentErrorLimit;
257     --errorCount;
258 
259     switch (res) {
260     case -1:
261       error("error handling script '" + errorHandlingScript +
262             "' failed to execute");
263       break;
264     case -2:
265       error("error handling script '" + errorHandlingScript +
266             "' crashed or timeout");
267       break;
268     default:
269       error("error handling script '" + errorHandlingScript +
270             "' exited with code " + Twine(res));
271     }
272   }
273 }
274 
275 void ErrorHandler::fatal(const Twine &msg) {
276   error(msg);
277   exitLld(1);
278 }
279