ubsan_diag.cc revision c1a1ed62228288155459d39194995a36aca4a8a6 
1//===-- ubsan_diag.cc -----------------------------------------------------===//
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// Diagnostic reporting for the UBSan runtime.
11//
12//===----------------------------------------------------------------------===//
13
14#include "ubsan_diag.h"
15#include "sanitizer_common/sanitizer_common.h"
16#include "sanitizer_common/sanitizer_libc.h"
17#include "sanitizer_common/sanitizer_report_decorator.h"
18#include "sanitizer_common/sanitizer_stacktrace.h"
19#include "sanitizer_common/sanitizer_symbolizer.h"
20#include <stdio.h>
21
22using namespace __ubsan;
23
24Location __ubsan::getCallerLocation(uptr CallerLoc) {
25  if (!CallerLoc)
26    return Location();
27
28  uptr Loc = StackTrace::GetPreviousInstructionPc(CallerLoc);
29  return getFunctionLocation(Loc, 0);
30}
31
32Location __ubsan::getFunctionLocation(uptr Loc, const char **FName) {
33  if (!Loc)
34    return Location();
35
36  AddressInfo Info;
37  if (!Symbolizer::GetOrInit()->SymbolizeCode(Loc, &Info, 1) ||
38      !Info.module || !*Info.module)
39    return Location(Loc);
40
41  if (FName && Info.function)
42    *FName = Info.function;
43
44  if (!Info.file)
45    return ModuleLocation(Info.module, Info.module_offset);
46
47  return SourceLocation(Info.file, Info.line, Info.column);
48}
49
50Diag &Diag::operator<<(const TypeDescriptor &V) {
51  return AddArg(V.getTypeName());
52}
53
54Diag &Diag::operator<<(const Value &V) {
55  if (V.getType().isSignedIntegerTy())
56    AddArg(V.getSIntValue());
57  else if (V.getType().isUnsignedIntegerTy())
58    AddArg(V.getUIntValue());
59  else if (V.getType().isFloatTy())
60    AddArg(V.getFloatValue());
61  else
62    AddArg("<unknown>");
63  return *this;
64}
65
66/// Hexadecimal printing for numbers too large for Printf to handle directly.
67static void PrintHex(UIntMax Val) {
68#if HAVE_INT128_T
69  Printf("0x%08x%08x%08x%08x",
70          (unsigned int)(Val >> 96),
71          (unsigned int)(Val >> 64),
72          (unsigned int)(Val >> 32),
73          (unsigned int)(Val));
74#else
75  UNREACHABLE("long long smaller than 64 bits?");
76#endif
77}
78
79static void renderLocation(Location Loc) {
80  switch (Loc.getKind()) {
81  case Location::LK_Source: {
82    SourceLocation SLoc = Loc.getSourceLocation();
83    if (SLoc.isInvalid())
84      Printf("<unknown>");
85    else
86      PrintSourceLocation(SLoc.getFilename(), SLoc.getLine(), SLoc.getColumn());
87    break;
88  }
89  case Location::LK_Module:
90    PrintModuleAndOffset(Loc.getModuleLocation().getModuleName(),
91                         Loc.getModuleLocation().getOffset());
92    break;
93  case Location::LK_Memory:
94    Printf("%p", Loc.getMemoryLocation());
95    break;
96  case Location::LK_Null:
97    Printf("<unknown>");
98    break;
99  }
100  Printf(":");
101}
102
103static void renderText(const char *Message, const Diag::Arg *Args) {
104  for (const char *Msg = Message; *Msg; ++Msg) {
105    if (*Msg != '%') {
106      char Buffer[64];
107      unsigned I;
108      for (I = 0; Msg[I] && Msg[I] != '%' && I != 63; ++I)
109        Buffer[I] = Msg[I];
110      Buffer[I] = '\0';
111      Printf(Buffer);
112      Msg += I - 1;
113    } else {
114      const Diag::Arg &A = Args[*++Msg - '0'];
115      switch (A.Kind) {
116      case Diag::AK_String:
117        Printf("%s", A.String);
118        break;
119      case Diag::AK_Mangled: {
120        Printf("'%s'", Symbolizer::GetOrInit()->Demangle(A.String));
121        break;
122      }
123      case Diag::AK_SInt:
124        // 'long long' is guaranteed to be at least 64 bits wide.
125        if (A.SInt >= INT64_MIN && A.SInt <= INT64_MAX)
126          Printf("%lld", (long long)A.SInt);
127        else
128          PrintHex(A.SInt);
129        break;
130      case Diag::AK_UInt:
131        if (A.UInt <= UINT64_MAX)
132          Printf("%llu", (unsigned long long)A.UInt);
133        else
134          PrintHex(A.UInt);
135        break;
136      case Diag::AK_Float: {
137        // FIXME: Support floating-point formatting in sanitizer_common's
138        //        printf, and stop using snprintf here.
139        char Buffer[32];
140        snprintf(Buffer, sizeof(Buffer), "%Lg", (long double)A.Float);
141        Printf("%s", Buffer);
142        break;
143      }
144      case Diag::AK_Pointer:
145        Printf("%p", A.Pointer);
146        break;
147      }
148    }
149  }
150}
151
152/// Find the earliest-starting range in Ranges which ends after Loc.
153static Range *upperBound(MemoryLocation Loc, Range *Ranges,
154                         unsigned NumRanges) {
155  Range *Best = 0;
156  for (unsigned I = 0; I != NumRanges; ++I)
157    if (Ranges[I].getEnd().getMemoryLocation() > Loc &&
158        (!Best ||
159         Best->getStart().getMemoryLocation() >
160         Ranges[I].getStart().getMemoryLocation()))
161      Best = &Ranges[I];
162  return Best;
163}
164
165/// Render a snippet of the address space near a location.
166static void renderMemorySnippet(const __sanitizer::AnsiColorDecorator &Decor,
167                                MemoryLocation Loc,
168                                Range *Ranges, unsigned NumRanges,
169                                const Diag::Arg *Args) {
170  const unsigned BytesToShow = 32;
171  const unsigned MinBytesNearLoc = 4;
172
173  // Show at least the 8 bytes surrounding Loc.
174  MemoryLocation Min = Loc - MinBytesNearLoc, Max = Loc + MinBytesNearLoc;
175  for (unsigned I = 0; I < NumRanges; ++I) {
176    Min = __sanitizer::Min(Ranges[I].getStart().getMemoryLocation(), Min);
177    Max = __sanitizer::Max(Ranges[I].getEnd().getMemoryLocation(), Max);
178  }
179
180  // If we have too many interesting bytes, prefer to show bytes after Loc.
181  if (Max - Min > BytesToShow)
182    Min = __sanitizer::Min(Max - BytesToShow, Loc - MinBytesNearLoc);
183  Max = Min + BytesToShow;
184
185  // Emit data.
186  for (uptr P = Min; P != Max; ++P) {
187    // FIXME: Check that the address is readable before printing it.
188    unsigned char C = *reinterpret_cast<const unsigned char*>(P);
189    Printf("%s%02x", (P % 8 == 0) ? "  " : " ", C);
190  }
191  Printf("\n");
192
193  // Emit highlights.
194  Printf(Decor.Green());
195  Range *InRange = upperBound(Min, Ranges, NumRanges);
196  for (uptr P = Min; P != Max; ++P) {
197    char Pad = ' ', Byte = ' ';
198    if (InRange && InRange->getEnd().getMemoryLocation() == P)
199      InRange = upperBound(P, Ranges, NumRanges);
200    if (!InRange && P > Loc)
201      break;
202    if (InRange && InRange->getStart().getMemoryLocation() < P)
203      Pad = '~';
204    if (InRange && InRange->getStart().getMemoryLocation() <= P)
205      Byte = '~';
206    char Buffer[] = { Pad, Pad, P == Loc ? '^' : Byte, Byte, 0 };
207    Printf((P % 8 == 0) ? Buffer : &Buffer[1]);
208  }
209  Printf("%s\n", Decor.Default());
210
211  // Go over the line again, and print names for the ranges.
212  InRange = 0;
213  unsigned Spaces = 0;
214  for (uptr P = Min; P != Max; ++P) {
215    if (!InRange || InRange->getEnd().getMemoryLocation() == P)
216      InRange = upperBound(P, Ranges, NumRanges);
217    if (!InRange)
218      break;
219
220    Spaces += (P % 8) == 0 ? 2 : 1;
221
222    if (InRange && InRange->getStart().getMemoryLocation() == P) {
223      while (Spaces--)
224        Printf(" ");
225      renderText(InRange->getText(), Args);
226      Printf("\n");
227      // FIXME: We only support naming one range for now!
228      break;
229    }
230
231    Spaces += 2;
232  }
233
234  // FIXME: Print names for anything we can identify within the line:
235  //
236  //  * If we can identify the memory itself as belonging to a particular
237  //    global, stack variable, or dynamic allocation, then do so.
238  //
239  //  * If we have a pointer-size, pointer-aligned range highlighted,
240  //    determine whether the value of that range is a pointer to an
241  //    entity which we can name, and if so, print that name.
242  //
243  // This needs an external symbolizer, or (preferably) ASan instrumentation.
244}
245
246Diag::~Diag() {
247  __sanitizer::AnsiColorDecorator Decor(PrintsToTty());
248  SpinMutexLock l(&CommonSanitizerReportMutex);
249  Printf(Decor.Bold());
250
251  renderLocation(Loc);
252
253  switch (Level) {
254  case DL_Error:
255    Printf("%s runtime error: %s%s",
256           Decor.Red(), Decor.Default(), Decor.Bold());
257    break;
258
259  case DL_Note:
260    Printf("%s note: %s", Decor.Black(), Decor.Default());
261    break;
262  }
263
264  renderText(Message, Args);
265
266  Printf("%s\n", Decor.Default());
267
268  if (Loc.isMemoryLocation())
269    renderMemorySnippet(Decor, Loc.getMemoryLocation(), Ranges,
270                        NumRanges, Args);
271}
272