1//===- llvm/Support/PrettyStackTrace.h - Pretty Crash Handling --*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file defines the PrettyStackTraceEntry class, which is used to make
11// crashes give more contextual information about what the program was doing
12// when it crashed.
13//
14//===----------------------------------------------------------------------===//
15
16#ifndef LLVM_SUPPORT_PRETTYSTACKTRACE_H
17#define LLVM_SUPPORT_PRETTYSTACKTRACE_H
18
19#include "llvm/Support/Compiler.h"
20
21namespace llvm {
22  class raw_ostream;
23
24  void EnablePrettyStackTrace();
25
26  /// PrettyStackTraceEntry - This class is used to represent a frame of the
27  /// "pretty" stack trace that is dumped when a program crashes. You can define
28  /// subclasses of this and declare them on the program stack: when they are
29  /// constructed and destructed, they will add their symbolic frames to a
30  /// virtual stack trace.  This gets dumped out if the program crashes.
31  class PrettyStackTraceEntry {
32    friend PrettyStackTraceEntry *ReverseStackTrace(PrettyStackTraceEntry *);
33
34    PrettyStackTraceEntry *NextEntry;
35    PrettyStackTraceEntry(const PrettyStackTraceEntry &) = delete;
36    void operator=(const PrettyStackTraceEntry &) = delete;
37  public:
38    PrettyStackTraceEntry();
39    virtual ~PrettyStackTraceEntry();
40
41    /// print - Emit information about this stack frame to OS.
42    virtual void print(raw_ostream &OS) const = 0;
43
44    /// getNextEntry - Return the next entry in the list of frames.
45    const PrettyStackTraceEntry *getNextEntry() const { return NextEntry; }
46  };
47
48  /// PrettyStackTraceString - This object prints a specified string (which
49  /// should not contain newlines) to the stream as the stack trace when a crash
50  /// occurs.
51  class PrettyStackTraceString : public PrettyStackTraceEntry {
52    const char *Str;
53  public:
54    PrettyStackTraceString(const char *str) : Str(str) {}
55    void print(raw_ostream &OS) const override;
56  };
57
58  /// PrettyStackTraceProgram - This object prints a specified program arguments
59  /// to the stream as the stack trace when a crash occurs.
60  class PrettyStackTraceProgram : public PrettyStackTraceEntry {
61    int ArgC;
62    const char *const *ArgV;
63  public:
64    PrettyStackTraceProgram(int argc, const char * const*argv)
65      : ArgC(argc), ArgV(argv) {
66      EnablePrettyStackTrace();
67    }
68    void print(raw_ostream &OS) const override;
69  };
70
71  /// Returns the topmost element of the "pretty" stack state.
72  const void *SavePrettyStackState();
73
74  /// Restores the topmost element of the "pretty" stack state to State, which
75  /// should come from a previous call to SavePrettyStackState().  This is
76  /// useful when using a CrashRecoveryContext in code that also uses
77  /// PrettyStackTraceEntries, to make sure the stack that's printed if a crash
78  /// happens after a crash that's been recovered by CrashRecoveryContext
79  /// doesn't have frames on it that were added in code unwound by the
80  /// CrashRecoveryContext.
81  void RestorePrettyStackState(const void *State);
82
83} // end namespace llvm
84
85#endif
86