1 /*
2  * Copyright (C) 2015 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #ifndef ART_COMPILER_CFI_TEST_H_
18 #define ART_COMPILER_CFI_TEST_H_
19 
20 #include <vector>
21 #include <memory>
22 #include <sstream>
23 
24 #include "arch/instruction_set.h"
25 #include "debug/dwarf/dwarf_constants.h"
26 #include "debug/dwarf/dwarf_test.h"
27 #include "debug/dwarf/headers.h"
28 #include "disassembler/disassembler.h"
29 #include "gtest/gtest.h"
30 
31 namespace art {
32 
33 constexpr dwarf::CFIFormat kCFIFormat = dwarf::DW_DEBUG_FRAME_FORMAT;
34 
35 class CFITest : public dwarf::DwarfTest {
36  public:
GenerateExpected(FILE * f,InstructionSet isa,const char * isa_str,const std::vector<uint8_t> & actual_asm,const std::vector<uint8_t> & actual_cfi)37   void GenerateExpected(FILE* f, InstructionSet isa, const char* isa_str,
38                         const std::vector<uint8_t>& actual_asm,
39                         const std::vector<uint8_t>& actual_cfi) {
40     std::vector<std::string> lines;
41     // Print the raw bytes.
42     fprintf(f, "static constexpr uint8_t expected_asm_%s[] = {", isa_str);
43     HexDump(f, actual_asm);
44     fprintf(f, "\n};\n");
45     fprintf(f, "static constexpr uint8_t expected_cfi_%s[] = {", isa_str);
46     HexDump(f, actual_cfi);
47     fprintf(f, "\n};\n");
48     // Pretty-print CFI opcodes.
49     constexpr bool is64bit = false;
50     dwarf::DebugFrameOpCodeWriter<> initial_opcodes;
51     dwarf::WriteCIE(is64bit, dwarf::Reg(8),
52                     initial_opcodes, kCFIFormat, &debug_frame_data_);
53     std::vector<uintptr_t> debug_frame_patches;
54     dwarf::WriteFDE(is64bit, 0, 0, 0, actual_asm.size(), ArrayRef<const uint8_t>(actual_cfi),
55                     kCFIFormat, 0, &debug_frame_data_, &debug_frame_patches);
56     ReformatCfi(Objdump(false, "-W"), &lines);
57     // Pretty-print assembly.
58     const uint8_t* asm_base = actual_asm.data();
59     const uint8_t* asm_end = asm_base + actual_asm.size();
60     auto* opts = new DisassemblerOptions(false, asm_base, asm_end, true);
61     std::unique_ptr<Disassembler> disasm(Disassembler::Create(isa, opts));
62     std::stringstream stream;
63     const uint8_t* base = actual_asm.data() + (isa == kThumb2 ? 1 : 0);
64     disasm->Dump(stream, base, base + actual_asm.size());
65     ReformatAsm(&stream, &lines);
66     // Print CFI and assembly interleaved.
67     std::stable_sort(lines.begin(), lines.end(), CompareByAddress);
68     for (const std::string& line : lines) {
69       fprintf(f, "// %s\n", line.c_str());
70     }
71     fprintf(f, "\n");
72   }
73 
74  private:
75   // Helper - get offset just past the end of given string.
FindEndOf(const std::string & str,const char * substr)76   static size_t FindEndOf(const std::string& str, const char* substr) {
77     size_t pos = str.find(substr);
78     CHECK_NE(std::string::npos, pos);
79     return pos + strlen(substr);
80   }
81 
82   // Spit to lines and remove raw instruction bytes.
ReformatAsm(std::stringstream * stream,std::vector<std::string> * output)83   static void ReformatAsm(std::stringstream* stream,
84                           std::vector<std::string>* output) {
85     std::string line;
86     while (std::getline(*stream, line)) {
87       line = line.substr(0, FindEndOf(line, ": ")) +
88              line.substr(FindEndOf(line, "\t"));
89       size_t pos;
90       while ((pos = line.find("  ")) != std::string::npos) {
91         line = line.replace(pos, 2, " ");
92       }
93       while (!line.empty() && line.back() == ' ') {
94         line.pop_back();
95       }
96       output->push_back(line);
97     }
98   }
99 
100   // Find interesting parts of objdump output and prefix the lines with address.
ReformatCfi(const std::vector<std::string> & lines,std::vector<std::string> * output)101   static void ReformatCfi(const std::vector<std::string>& lines,
102                           std::vector<std::string>* output) {
103     std::string address;
104     for (const std::string& line : lines) {
105       if (line.find("DW_CFA_nop") != std::string::npos) {
106         // Ignore.
107       } else if (line.find("DW_CFA_advance_loc") != std::string::npos) {
108         // The last 8 characters are the address.
109         address = "0x" + line.substr(line.size() - 8);
110       } else if (line.find("DW_CFA_") != std::string::npos) {
111         std::string new_line(line);
112         // "bad register" warning is caused by always using host (x86) objdump.
113         const char* bad_reg = "bad register: ";
114         size_t pos;
115         if ((pos = new_line.find(bad_reg)) != std::string::npos) {
116           new_line = new_line.replace(pos, strlen(bad_reg), "");
117         }
118         // Remove register names in parentheses since they have x86 names.
119         if ((pos = new_line.find(" (")) != std::string::npos) {
120           new_line = new_line.replace(pos, FindEndOf(new_line, ")") - pos, "");
121         }
122         // Use the .cfi_ prefix.
123         new_line = ".cfi_" + new_line.substr(FindEndOf(new_line, "DW_CFA_"));
124         output->push_back(address + ": " + new_line);
125       }
126     }
127   }
128 
129   // Compare strings by the address prefix.
CompareByAddress(const std::string & lhs,const std::string & rhs)130   static bool CompareByAddress(const std::string& lhs, const std::string& rhs) {
131     EXPECT_EQ(lhs[10], ':');
132     EXPECT_EQ(rhs[10], ':');
133     return strncmp(lhs.c_str(), rhs.c_str(), 10) < 0;
134   }
135 
136   // Pretty-print byte array.  12 bytes per line.
HexDump(FILE * f,const std::vector<uint8_t> & data)137   static void HexDump(FILE* f, const std::vector<uint8_t>& data) {
138     for (size_t i = 0; i < data.size(); i++) {
139       fprintf(f, i % 12 == 0 ? "\n    " : " ");  // Whitespace.
140       fprintf(f, "0x%02X,", data[i]);
141     }
142   }
143 };
144 
145 }  // namespace art
146 
147 #endif  // ART_COMPILER_CFI_TEST_H_
148