xref: /llvm-project/llvm/tools/llvm-readobj/ObjDumper.cpp (revision 3297858c19f3914513041d2c8407bc26c889793a) 
1 //===-- ObjDumper.cpp - Base dumper class -----------------------*- 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 /// \file
10 /// This file implements ObjDumper.
11 ///
12 //===----------------------------------------------------------------------===//
13 
14 #include "ObjDumper.h"
15 #include "llvm-readobj.h"
16 #include "llvm/Object/Archive.h"
17 #include "llvm/Object/Decompressor.h"
18 #include "llvm/Object/ObjectFile.h"
19 #include "llvm/Support/Error.h"
20 #include "llvm/Support/FormatVariadic.h"
21 #include "llvm/Support/ScopedPrinter.h"
22 #include "llvm/Support/SystemZ/zOSSupport.h"
23 #include "llvm/Support/raw_ostream.h"
24 #include <map>
25 
26 namespace llvm {
27 
28 static inline Error createError(const Twine &Msg) {
29   return createStringError(object::object_error::parse_failed, Msg);
30 }
31 
32 ObjDumper::ObjDumper(ScopedPrinter &Writer, StringRef ObjName) : W(Writer) {
33   // Dumper reports all non-critical errors as warnings.
34   // It does not print the same warning more than once.
35   WarningHandler = [=](const Twine &Msg) {
36     if (Warnings.insert(Msg.str()).second)
37       reportWarning(createError(Msg), ObjName);
38     return Error::success();
39   };
40 }
41 
42 ObjDumper::~ObjDumper() {}
43 
44 void ObjDumper::reportUniqueWarning(Error Err) const {
45   reportUniqueWarning(toString(std::move(Err)));
46 }
47 
48 void ObjDumper::reportUniqueWarning(const Twine &Msg) const {
49   cantFail(WarningHandler(Msg),
50            "WarningHandler should always return ErrorSuccess");
51 }
52 
53 static void printAsPrintable(raw_ostream &W, const uint8_t *Start, size_t Len) {
54   for (size_t i = 0; i < Len; i++)
55     W << (isPrint(Start[i]) ? static_cast<char>(Start[i]) : '.');
56 }
57 
58 void ObjDumper::printAsStringList(StringRef StringContent,
59                                   size_t StringDataOffset) {
60   size_t StrSize = StringContent.size();
61   if (StrSize == 0)
62     return;
63   if (StrSize < StringDataOffset) {
64     reportUniqueWarning("offset (0x" + Twine::utohexstr(StringDataOffset) +
65                         ") is past the end of the contents (size 0x" +
66                         Twine::utohexstr(StrSize) + ")");
67     return;
68   }
69 
70   const uint8_t *StrContent = StringContent.bytes_begin();
71   // Some formats contain additional metadata at the start which should not be
72   // interpreted as strings. Skip these bytes, but account for them in the
73   // string offsets.
74   const uint8_t *CurrentWord = StrContent + StringDataOffset;
75   const uint8_t *StrEnd = StringContent.bytes_end();
76 
77   while (CurrentWord <= StrEnd) {
78     size_t WordSize = strnlen(reinterpret_cast<const char *>(CurrentWord),
79                               StrEnd - CurrentWord);
80     if (!WordSize) {
81       CurrentWord++;
82       continue;
83     }
84     W.startLine() << format("[%6tx] ", CurrentWord - StrContent);
85     printAsPrintable(W.getOStream(), CurrentWord, WordSize);
86     W.getOStream() << '\n';
87     CurrentWord += WordSize + 1;
88   }
89 }
90 
91 void ObjDumper::printFileSummary(StringRef FileStr, object::ObjectFile &Obj,
92                                  ArrayRef<std::string> InputFilenames,
93                                  const object::Archive *A) {
94   if (!FileStr.empty()) {
95     W.getOStream() << "\n";
96     W.printString("File", FileStr);
97   }
98   W.printString("Format", Obj.getFileFormatName());
99   W.printString("Arch", Triple::getArchTypeName(Obj.getArch()));
100   W.printString("AddressSize",
101                 std::string(formatv("{0}bit", 8 * Obj.getBytesInAddress())));
102   this->printLoadName();
103 }
104 
105 static std::vector<object::SectionRef>
106 getSectionRefsByNameOrIndex(const object::ObjectFile &Obj,
107                             ArrayRef<std::string> Sections) {
108   std::vector<object::SectionRef> Ret;
109   std::map<std::string, bool, std::less<>> SecNames;
110   std::map<unsigned, bool> SecIndices;
111   unsigned SecIndex;
112   for (StringRef Section : Sections) {
113     if (!Section.getAsInteger(0, SecIndex))
114       SecIndices.emplace(SecIndex, false);
115     else
116       SecNames.emplace(std::string(Section), false);
117   }
118 
119   SecIndex = Obj.isELF() ? 0 : 1;
120   for (object::SectionRef SecRef : Obj.sections()) {
121     StringRef SecName = unwrapOrError(Obj.getFileName(), SecRef.getName());
122     auto NameIt = SecNames.find(SecName);
123     if (NameIt != SecNames.end())
124       NameIt->second = true;
125     auto IndexIt = SecIndices.find(SecIndex);
126     if (IndexIt != SecIndices.end())
127       IndexIt->second = true;
128     if (NameIt != SecNames.end() || IndexIt != SecIndices.end())
129       Ret.push_back(SecRef);
130     SecIndex++;
131   }
132 
133   for (const std::pair<const std::string, bool> &S : SecNames)
134     if (!S.second)
135       reportWarning(
136           createError(formatv("could not find section '{0}'", S.first).str()),
137           Obj.getFileName());
138 
139   for (std::pair<unsigned, bool> S : SecIndices)
140     if (!S.second)
141       reportWarning(
142           createError(formatv("could not find section {0}", S.first).str()),
143           Obj.getFileName());
144 
145   return Ret;
146 }
147 
148 static void maybeDecompress(const object::ObjectFile &Obj,
149                             StringRef SectionName, StringRef &SectionContent,
150                             SmallString<0> &Out) {
151   Expected<object::Decompressor> Decompressor = object::Decompressor::create(
152       SectionName, SectionContent, Obj.isLittleEndian(), Obj.is64Bit());
153   if (!Decompressor)
154     reportWarning(Decompressor.takeError(), Obj.getFileName());
155   else if (auto Err = Decompressor->resizeAndDecompress(Out))
156     reportWarning(std::move(Err), Obj.getFileName());
157   else
158     SectionContent = Out;
159 }
160 
161 void ObjDumper::printSectionsAsString(const object::ObjectFile &Obj,
162                                       ArrayRef<std::string> Sections,
163                                       bool Decompress) {
164   SmallString<0> Out;
165   for (object::SectionRef Section :
166        getSectionRefsByNameOrIndex(Obj, Sections)) {
167     StringRef SectionName = unwrapOrError(Obj.getFileName(), Section.getName());
168     W.getOStream() << '\n';
169     W.startLine() << "String dump of section '" << SectionName << "':\n";
170 
171     StringRef SectionContent =
172         unwrapOrError(Obj.getFileName(), Section.getContents());
173     if (Decompress && Section.isCompressed())
174       maybeDecompress(Obj, SectionName, SectionContent, Out);
175     printAsStringList(SectionContent);
176   }
177 }
178 
179 void ObjDumper::printSectionsAsHex(const object::ObjectFile &Obj,
180                                    ArrayRef<std::string> Sections,
181                                    bool Decompress) {
182   SmallString<0> Out;
183   for (object::SectionRef Section :
184        getSectionRefsByNameOrIndex(Obj, Sections)) {
185     StringRef SectionName = unwrapOrError(Obj.getFileName(), Section.getName());
186     W.getOStream() << '\n';
187     W.startLine() << "Hex dump of section '" << SectionName << "':\n";
188 
189     StringRef SectionContent =
190         unwrapOrError(Obj.getFileName(), Section.getContents());
191     if (Decompress && Section.isCompressed())
192       maybeDecompress(Obj, SectionName, SectionContent, Out);
193     const uint8_t *SecContent = SectionContent.bytes_begin();
194     const uint8_t *SecEnd = SecContent + SectionContent.size();
195 
196     for (const uint8_t *SecPtr = SecContent; SecPtr < SecEnd; SecPtr += 16) {
197       const uint8_t *TmpSecPtr = SecPtr;
198       uint8_t i;
199       uint8_t k;
200 
201       W.startLine() << format_hex(Section.getAddress() + (SecPtr - SecContent),
202                                   10);
203       W.getOStream() << ' ';
204       for (i = 0; TmpSecPtr < SecEnd && i < 4; ++i) {
205         for (k = 0; TmpSecPtr < SecEnd && k < 4; k++, TmpSecPtr++) {
206           uint8_t Val = *(reinterpret_cast<const uint8_t *>(TmpSecPtr));
207           W.getOStream() << format_hex_no_prefix(Val, 2);
208         }
209         W.getOStream() << ' ';
210       }
211 
212       // We need to print the correct amount of spaces to match the format.
213       // We are adding the (4 - i) last rows that are 8 characters each.
214       // Then, the (4 - i) spaces that are in between the rows.
215       // Least, if we cut in a middle of a row, we add the remaining characters,
216       // which is (8 - (k * 2)).
217       if (i < 4)
218         W.getOStream() << format("%*c", (4 - i) * 8 + (4 - i), ' ');
219       if (k < 4)
220         W.getOStream() << format("%*c", 8 - k * 2, ' ');
221 
222       TmpSecPtr = SecPtr;
223       for (i = 0; TmpSecPtr + i < SecEnd && i < 16; ++i)
224         W.getOStream() << (isPrint(TmpSecPtr[i])
225                                ? static_cast<char>(TmpSecPtr[i])
226                                : '.');
227 
228       W.getOStream() << '\n';
229     }
230   }
231 }
232 
233 } // namespace llvm
234