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/ADT/SmallVector.h"
20 #include "llvm/Support/Compiler.h"
21 
22 namespace llvm {
23   class raw_ostream;
24 
25   void EnablePrettyStackTrace();
26 
27   /// PrettyStackTraceEntry - This class is used to represent a frame of the
28   /// "pretty" stack trace that is dumped when a program crashes. You can define
29   /// subclasses of this and declare them on the program stack: when they are
30   /// constructed and destructed, they will add their symbolic frames to a
31   /// virtual stack trace.  This gets dumped out if the program crashes.
32   class PrettyStackTraceEntry {
33     friend PrettyStackTraceEntry *ReverseStackTrace(PrettyStackTraceEntry *);
34 
35     PrettyStackTraceEntry *NextEntry;
36     PrettyStackTraceEntry(const PrettyStackTraceEntry &) = delete;
37     void operator=(const PrettyStackTraceEntry &) = delete;
38   public:
39     PrettyStackTraceEntry();
40     virtual ~PrettyStackTraceEntry();
41 
42     /// print - Emit information about this stack frame to OS.
43     virtual void print(raw_ostream &OS) const = 0;
44 
45     /// getNextEntry - Return the next entry in the list of frames.
getNextEntry()46     const PrettyStackTraceEntry *getNextEntry() const { return NextEntry; }
47   };
48 
49   /// PrettyStackTraceString - This object prints a specified string (which
50   /// should not contain newlines) to the stream as the stack trace when a crash
51   /// occurs.
52   class PrettyStackTraceString : public PrettyStackTraceEntry {
53     const char *Str;
54   public:
PrettyStackTraceString(const char * str)55     PrettyStackTraceString(const char *str) : Str(str) {}
56     void print(raw_ostream &OS) const override;
57   };
58 
59   /// PrettyStackTraceFormat - This object prints a string (which may use
60   /// printf-style formatting but should not contain newlines) to the stream
61   /// as the stack trace when a crash occurs.
62   class PrettyStackTraceFormat : public PrettyStackTraceEntry {
63     llvm::SmallVector<char, 32> Str;
64   public:
65     PrettyStackTraceFormat(const char *Format, ...);
66     void print(raw_ostream &OS) const override;
67   };
68 
69   /// PrettyStackTraceProgram - This object prints a specified program arguments
70   /// to the stream as the stack trace when a crash occurs.
71   class PrettyStackTraceProgram : public PrettyStackTraceEntry {
72     int ArgC;
73     const char *const *ArgV;
74   public:
PrettyStackTraceProgram(int argc,const char * const * argv)75     PrettyStackTraceProgram(int argc, const char * const*argv)
76       : ArgC(argc), ArgV(argv) {
77       EnablePrettyStackTrace();
78     }
79     void print(raw_ostream &OS) const override;
80   };
81 
82   /// Returns the topmost element of the "pretty" stack state.
83   const void *SavePrettyStackState();
84 
85   /// Restores the topmost element of the "pretty" stack state to State, which
86   /// should come from a previous call to SavePrettyStackState().  This is
87   /// useful when using a CrashRecoveryContext in code that also uses
88   /// PrettyStackTraceEntries, to make sure the stack that's printed if a crash
89   /// happens after a crash that's been recovered by CrashRecoveryContext
90   /// doesn't have frames on it that were added in code unwound by the
91   /// CrashRecoveryContext.
92   void RestorePrettyStackState(const void *State);
93 
94 } // end namespace llvm
95 
96 #endif
97