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      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:
     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.
     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.
     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.
    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.
    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.
    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