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 "Error.h"
16 #include "llvm-readobj.h"
17 #include "llvm/Object/ObjectFile.h"
18 #include "llvm/Support/Error.h"
19 #include "llvm/Support/FormatVariadic.h"
20 #include "llvm/Support/ScopedPrinter.h"
21 #include "llvm/Support/raw_ostream.h"
22 #include <map>
23 
24 namespace llvm {
25 
26 static inline Error createError(const Twine &Msg) {
27   return createStringError(object::object_error::parse_failed, Msg);
28 }
29 
30 ObjDumper::ObjDumper(ScopedPrinter &Writer) : W(Writer) {}
31 
32 ObjDumper::~ObjDumper() {
33 }
34 
35 static void printAsPrintable(raw_ostream &W, const uint8_t *Start, size_t Len) {
36   for (size_t i = 0; i < Len; i++)
37     W << (isPrint(Start[i]) ? static_cast<char>(Start[i]) : '.');
38 }
39 
40 static std::vector<object::SectionRef>
41 getSectionRefsByNameOrIndex(const object::ObjectFile *Obj,
42                             ArrayRef<std::string> Sections) {
43   std::vector<object::SectionRef> Ret;
44   std::map<std::string, bool> SecNames;
45   std::map<unsigned, bool> SecIndices;
46   unsigned SecIndex;
47   for (StringRef Section : Sections) {
48     if (!Section.getAsInteger(0, SecIndex))
49       SecIndices.emplace(SecIndex, false);
50     else
51       SecNames.emplace(std::string(Section), false);
52   }
53 
54   SecIndex = Obj->isELF() ? 0 : 1;
55   for (object::SectionRef SecRef : Obj->sections()) {
56     StringRef SecName = unwrapOrError(Obj->getFileName(), SecRef.getName());
57     auto NameIt = SecNames.find(std::string(SecName));
58     if (NameIt != SecNames.end())
59       NameIt->second = true;
60     auto IndexIt = SecIndices.find(SecIndex);
61     if (IndexIt != SecIndices.end())
62       IndexIt->second = true;
63     if (NameIt != SecNames.end() || IndexIt != SecIndices.end())
64       Ret.push_back(SecRef);
65     SecIndex++;
66   }
67 
68   for (const std::pair<const std::string, bool> &S : SecNames)
69     if (!S.second)
70       reportWarning(
71           createError(formatv("could not find section '{0}'", S.first).str()),
72           Obj->getFileName());
73 
74   for (std::pair<unsigned, bool> S : SecIndices)
75     if (!S.second)
76       reportWarning(
77           createError(formatv("could not find section {0}", S.first).str()),
78           Obj->getFileName());
79 
80   return Ret;
81 }
82 
83 void ObjDumper::printSectionsAsString(const object::ObjectFile *Obj,
84                                       ArrayRef<std::string> Sections) {
85   bool First = true;
86   for (object::SectionRef Section :
87        getSectionRefsByNameOrIndex(Obj, Sections)) {
88     StringRef SectionName =
89         unwrapOrError(Obj->getFileName(), Section.getName());
90 
91     if (!First)
92       W.startLine() << '\n';
93     First = false;
94     W.startLine() << "String dump of section '" << SectionName << "':\n";
95 
96     StringRef SectionContent =
97         unwrapOrError(Obj->getFileName(), Section.getContents());
98 
99     const uint8_t *SecContent = SectionContent.bytes_begin();
100     const uint8_t *CurrentWord = SecContent;
101     const uint8_t *SecEnd = SectionContent.bytes_end();
102 
103     while (CurrentWord <= SecEnd) {
104       size_t WordSize = strnlen(reinterpret_cast<const char *>(CurrentWord),
105                                 SecEnd - CurrentWord);
106       if (!WordSize) {
107         CurrentWord++;
108         continue;
109       }
110       W.startLine() << format("[%6tx] ", CurrentWord - SecContent);
111       printAsPrintable(W.startLine(), CurrentWord, WordSize);
112       W.startLine() << '\n';
113       CurrentWord += WordSize + 1;
114     }
115   }
116 }
117 
118 void ObjDumper::printSectionsAsHex(const object::ObjectFile *Obj,
119                                    ArrayRef<std::string> Sections) {
120   bool First = true;
121   for (object::SectionRef Section :
122        getSectionRefsByNameOrIndex(Obj, Sections)) {
123     StringRef SectionName =
124         unwrapOrError(Obj->getFileName(), Section.getName());
125 
126     if (!First)
127       W.startLine() << '\n';
128     First = false;
129     W.startLine() << "Hex dump of section '" << SectionName << "':\n";
130 
131     StringRef SectionContent =
132         unwrapOrError(Obj->getFileName(), Section.getContents());
133     const uint8_t *SecContent = SectionContent.bytes_begin();
134     const uint8_t *SecEnd = SecContent + SectionContent.size();
135 
136     for (const uint8_t *SecPtr = SecContent; SecPtr < SecEnd; SecPtr += 16) {
137       const uint8_t *TmpSecPtr = SecPtr;
138       uint8_t i;
139       uint8_t k;
140 
141       W.startLine() << format_hex(Section.getAddress() + (SecPtr - SecContent),
142                                   10);
143       W.startLine() << ' ';
144       for (i = 0; TmpSecPtr < SecEnd && i < 4; ++i) {
145         for (k = 0; TmpSecPtr < SecEnd && k < 4; k++, TmpSecPtr++) {
146           uint8_t Val = *(reinterpret_cast<const uint8_t *>(TmpSecPtr));
147           W.startLine() << format_hex_no_prefix(Val, 2);
148         }
149         W.startLine() << ' ';
150       }
151 
152       // We need to print the correct amount of spaces to match the format.
153       // We are adding the (4 - i) last rows that are 8 characters each.
154       // Then, the (4 - i) spaces that are in between the rows.
155       // Least, if we cut in a middle of a row, we add the remaining characters,
156       // which is (8 - (k * 2)).
157       if (i < 4)
158         W.startLine() << format("%*c", (4 - i) * 8 + (4 - i) + (8 - (k * 2)),
159                                 ' ');
160 
161       TmpSecPtr = SecPtr;
162       for (i = 0; TmpSecPtr + i < SecEnd && i < 16; ++i)
163         W.startLine() << (isPrint(TmpSecPtr[i])
164                               ? static_cast<char>(TmpSecPtr[i])
165                               : '.');
166 
167       W.startLine() << '\n';
168     }
169   }
170 }
171 
172 } // namespace llvm
173