1 //===- ErrorCollector.h -----------------------------------------*- C++ -*-===//
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 /// This class collects errors that should be reported or ignored in aggregate.
10 ///
11 /// Like llvm::Error, an ErrorCollector cannot be copied. Unlike llvm::Error,
12 /// an ErrorCollector may be destroyed if it was originally constructed to treat
13 /// errors as non-fatal. In this case, all Errors are consumed upon destruction.
14 /// An ErrorCollector may be initially constructed (or escalated) such that
15 /// errors are treated as fatal. This causes a crash if an attempt is made to
16 /// delete the ErrorCollector when some Errors have not been retrieved via
17 /// makeError().
18 ///
19 //===-----------------------------------------------------------------------===/
20 
21 #ifndef LLVM_TOOLS_LLVM_IFS_ERRORCOLLECTOR_H
22 #define LLVM_TOOLS_LLVM_IFS_ERRORCOLLECTOR_H
23 
24 #include "llvm/Support/raw_ostream.h"
25 #include <vector>
26 
27 namespace llvm {
28 
29 class Error;
30 
31 namespace ifs {
32 
33 class ErrorCollector {
34 public:
35   /// Upon destruction, an ErrorCollector will crash if UseFatalErrors=true and
36   /// there are remaining errors that haven't been fetched by makeError().
ErrorsAreFatal(UseFatalErrors)37   ErrorCollector(bool UseFatalErrors = true) : ErrorsAreFatal(UseFatalErrors) {}
38   // Don't allow copying.
39   ErrorCollector(const ErrorCollector &Stub) = delete;
40   ErrorCollector &operator=(const ErrorCollector &Other) = delete;
41   ~ErrorCollector();
42 
43   // TODO: Add move constructor and operator= when a testable situation arises.
44 
45   /// Returns a single error that contains messages for all stored Errors.
46   Error makeError();
47 
48   /// Adds an error with a descriptive tag that helps with identification.
49   /// If the error is an Error::success(), it is checked and discarded.
50   void addError(Error &&E, StringRef Tag);
51 
52   /// This ensures an ErrorCollector will treat unhandled errors as fatal.
53   /// This function should be called if errors that usually can be ignored
54   /// are suddenly of concern (i.e. attempt multiple things that return Error,
55   /// but only care about the Errors if no attempt succeeds).
56   void escalateToFatal();
57 
58 private:
59   /// Logs all errors to a raw_ostream.
60   void log(raw_ostream &OS);
61 
62   /// Returns true if all errors have been retrieved through makeError(), or
63   /// false if errors have been added since the last makeError() call.
64   bool allErrorsHandled() const;
65 
66   /// Dump output and crash.
67   [[noreturn]] void fatalUnhandledError();
68 
69   bool ErrorsAreFatal;
70   std::vector<Error> Errors;
71   std::vector<std::string> Tags;
72 };
73 
74 } // end namespace ifs
75 } // end namespace llvm
76 
77 #endif // LLVM_TOOLS_LLVM_IFS_ERRORCOLLECTOR_H
78