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