1//===- llvm/Support/PrettyStackTrace.h - Pretty Crash Handling --*- 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 file defines the PrettyStackTraceEntry class, which is used to make
10// crashes give more contextual information about what the program was doing
11// when it crashed.
12//
13//===----------------------------------------------------------------------===//
14
15#ifndef LLVM_SUPPORT_PRETTYSTACKTRACE_H
16#define LLVM_SUPPORT_PRETTYSTACKTRACE_H
17
18#include "llvm/ADT/SmallVector.h"
19#include "llvm/Support/Compiler.h"
20
21namespace llvm {
22 class raw_ostream;
23
24 /// Enables dumping a "pretty" stack trace when the program crashes.
25 ///
26 /// \see PrettyStackTraceEntry
27 void EnablePrettyStackTrace();
28
29 /// Enables (or disables) dumping a "pretty" stack trace when the user sends
30 /// SIGINFO or SIGUSR1 to the current process.
31 ///
32 /// This is a per-thread decision so that a program can choose to print stack
33 /// traces only on a primary thread, or on all threads that use
34 /// PrettyStackTraceEntry.
35 ///
36 /// \see EnablePrettyStackTrace
37 /// \see PrettyStackTraceEntry
38 void EnablePrettyStackTraceOnSigInfoForThisThread(bool ShouldEnable = true);
39
40 /// Replaces the generic bug report message that is output upon
41 /// a crash.
42 void setBugReportMsg(const char *Msg);
43
44 /// Get the bug report message that will be output upon a crash.
45 const char *getBugReportMsg();
46
47 /// PrettyStackTraceEntry - This class is used to represent a frame of the
48 /// "pretty" stack trace that is dumped when a program crashes. You can define
49 /// subclasses of this and declare them on the program stack: when they are
50 /// constructed and destructed, they will add their symbolic frames to a
51 /// virtual stack trace. This gets dumped out if the program crashes.
52 class PrettyStackTraceEntry {
53 friend PrettyStackTraceEntry *ReverseStackTrace(PrettyStackTraceEntry *);
54
55 PrettyStackTraceEntry *NextEntry;
56 PrettyStackTraceEntry(const PrettyStackTraceEntry &) = delete;
57 void operator=(const PrettyStackTraceEntry &) = delete;
58 public:
59 PrettyStackTraceEntry();
60 virtual ~PrettyStackTraceEntry();
61
62 /// print - Emit information about this stack frame to OS.
63 virtual void print(raw_ostream &OS) const = 0;
64
65 /// getNextEntry - Return the next entry in the list of frames.
66 const PrettyStackTraceEntry *getNextEntry() const { return NextEntry; }
67 };
68
69 /// PrettyStackTraceString - This object prints a specified string (which
70 /// should not contain newlines) to the stream as the stack trace when a crash
71 /// occurs.
72 class PrettyStackTraceString : public PrettyStackTraceEntry {
73 const char *Str;
74 public:
75 PrettyStackTraceString(const char *str) : Str(str) {}
76 void print(raw_ostream &OS) const override;
77 };
78
79 /// PrettyStackTraceFormat - This object prints a string (which may use
80 /// printf-style formatting but should not contain newlines) to the stream
81 /// as the stack trace when a crash occurs.
82 class PrettyStackTraceFormat : public PrettyStackTraceEntry {
83 llvm::SmallVector<char, 32> Str;
84 public:
85 PrettyStackTraceFormat(const char *Format, ...);
86 void print(raw_ostream &OS) const override;
87 };
88
89 /// PrettyStackTraceProgram - This object prints a specified program arguments
90 /// to the stream as the stack trace when a crash occurs.
91 class PrettyStackTraceProgram : public PrettyStackTraceEntry {
92 int ArgC;
93 const char *const *ArgV;
94 public:
95 PrettyStackTraceProgram(int argc, const char * const*argv)
96 : ArgC(argc), ArgV(argv) {
97 EnablePrettyStackTrace();
98 }
99 void print(raw_ostream &OS) const override;
100 };
101
102 /// Returns the topmost element of the "pretty" stack state.
103 const void *SavePrettyStackState();
104
105 /// Restores the topmost element of the "pretty" stack state to State, which
106 /// should come from a previous call to SavePrettyStackState(). This is
107 /// useful when using a CrashRecoveryContext in code that also uses
108 /// PrettyStackTraceEntries, to make sure the stack that's printed if a crash
109 /// happens after a crash that's been recovered by CrashRecoveryContext
110 /// doesn't have frames on it that were added in code unwound by the
111 /// CrashRecoveryContext.
112 void RestorePrettyStackState(const void *State);
113
114} // end namespace llvm
115
116#endif
117