Libraries: Move to Userland/Libraries/

1 files changed, 269 insertions, 0 deletions

diff --git a/Userland/Libraries/LibDebug/Dwarf/LineProgram.cpp b/Userland/Libraries/LibDebug/Dwarf/LineProgram.cpp
new file mode 100644
index 0000000000..2bc89a885f
--- /dev/null
+++ b/Userland/Libraries/LibDebug/Dwarf/LineProgram.cpp
@@ -0,0 +1,269 @@
+/*
+ * Copyright (c) 2020, Itamar S. <itamar8910@gmail.com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "LineProgram.h"
+#include <AK/String.h>
+#include <AK/StringBuilder.h>
+
+//#define DWARF_DEBUG
+
+namespace Debug::Dwarf {
+
+LineProgram::LineProgram(InputMemoryStream& stream)
+    : m_stream(stream)
+{
+    m_unit_offset = m_stream.offset();
+    parse_unit_header();
+    parse_source_directories();
+    parse_source_files();
+    run_program();
+}
+
+void LineProgram::parse_unit_header()
+{
+    m_stream >> Bytes { &m_unit_header, sizeof(m_unit_header) };
+
+    ASSERT(m_unit_header.version == DWARF_VERSION);
+    ASSERT(m_unit_header.opcode_base == SPECIAL_OPCODES_BASE);
+
+#ifdef DWARF_DEBUG
+    dbgln("unit length: {}", m_unit_header.length);
+#endif
+}
+
+void LineProgram::parse_source_directories()
+{
+    m_source_directories.append(".");
+
+    while (m_stream.peek_or_error()) {
+        String directory;
+        m_stream >> directory;
+#ifdef DWARF_DEBUG
+        dbgln("directory: {}", directory);
+#endif
+        m_source_directories.append(move(directory));
+    }
+    m_stream.handle_recoverable_error();
+    m_stream.discard_or_error(1);
+    ASSERT(!m_stream.has_any_error());
+}
+
+void LineProgram::parse_source_files()
+{
+    m_source_files.append({ ".", 0 });
+    while (!m_stream.eof() && m_stream.peek_or_error()) {
+        String file_name;
+        m_stream >> file_name;
+        size_t directory_index = 0;
+        m_stream.read_LEB128_unsigned(directory_index);
+        size_t _unused = 0;
+        m_stream.read_LEB128_unsigned(_unused); // skip modification time
+        m_stream.read_LEB128_unsigned(_unused); // skip file size
+#ifdef DWARF_DEBUG
+        dbgln("file: {}, directory index: {}", file_name, directory_index);
+#endif
+        m_source_files.append({ file_name, directory_index });
+    }
+    m_stream.discard_or_error(1);
+    ASSERT(!m_stream.has_any_error());
+}
+
+void LineProgram::append_to_line_info()
+{
+#ifdef DWARF_DEBUG
+    dbgln("appending line info: {:p}, {}:{}", m_address, m_source_files[m_file_index].name, m_line);
+#endif
+    if (!m_is_statement)
+        return;
+
+    String directory = m_source_directories[m_source_files[m_file_index].directory_index];
+
+    StringBuilder full_path(directory.length() + m_source_files[m_file_index].name.length() + 1);
+    full_path.append(directory);
+    full_path.append('/');
+    full_path.append(m_source_files[m_file_index].name);
+
+    m_lines.append({ m_address, full_path.to_string(), m_line });
+}
+
+void LineProgram::reset_registers()
+{
+    m_address = 0;
+    m_line = 1;
+    m_file_index = 1;
+    m_is_statement = m_unit_header.default_is_stmt == 1;
+}
+
+void LineProgram::handle_extended_opcode()
+{
+    size_t length = 0;
+    m_stream.read_LEB128_unsigned(length);
+
+    u8 sub_opcode = 0;
+    m_stream >> sub_opcode;
+
+    switch (sub_opcode) {
+    case ExtendedOpcodes::EndSequence: {
+        append_to_line_info();
+        reset_registers();
+        break;
+    }
+    case ExtendedOpcodes::SetAddress: {
+        ASSERT(length == sizeof(size_t) + 1);
+        m_stream >> m_address;
+#ifdef DWARF_DEBUG
+        dbgln("SetAddress: {:p}", m_address);
+#endif
+        break;
+    }
+    case ExtendedOpcodes::SetDiscriminator: {
+#ifdef DWARF_DEBUG
+        dbgln("SetDiscriminator");
+#endif
+        m_stream.discard_or_error(1);
+        break;
+    }
+    default:
+#ifdef DWARF_DEBUG
+        dbgln("offset: {:p}", m_stream.offset());
+#endif
+        ASSERT_NOT_REACHED();
+    }
+}
+void LineProgram::handle_standard_opcode(u8 opcode)
+{
+    switch (opcode) {
+    case StandardOpcodes::Copy: {
+        append_to_line_info();
+        break;
+    }
+    case StandardOpcodes::AdvancePc: {
+        size_t operand = 0;
+        m_stream.read_LEB128_unsigned(operand);
+        size_t delta = operand * m_unit_header.min_instruction_length;
+#ifdef DWARF_DEBUG
+        dbgln("AdvancePC by: {} to: {:p}", delta, m_address + delta);
+#endif
+        m_address += delta;
+        break;
+    }
+    case StandardOpcodes::SetFile: {
+        size_t new_file_index = 0;
+        m_stream.read_LEB128_unsigned(new_file_index);
+#ifdef DWARF_DEBUG
+        dbgln("SetFile: new file index: {}", new_file_index);
+#endif
+        m_file_index = new_file_index;
+        break;
+    }
+    case StandardOpcodes::SetColumn: {
+        // not implemented
+#ifdef DWARF_DEBUG
+        dbgln("SetColumn");
+#endif
+        size_t new_column;
+        m_stream.read_LEB128_unsigned(new_column);
+
+        break;
+    }
+    case StandardOpcodes::AdvanceLine: {
+        ssize_t line_delta;
+        m_stream.read_LEB128_signed(line_delta);
+        ASSERT(line_delta >= 0 || m_line >= (size_t)(-line_delta));
+        m_line += line_delta;
+#ifdef DWARF_DEBUG
+        dbgln("AdvanceLine: {}", m_line);
+#endif
+        break;
+    }
+    case StandardOpcodes::NegateStatement: {
+#ifdef DWARF_DEBUG
+        dbgln("NegateStatement");
+#endif
+        m_is_statement = !m_is_statement;
+        break;
+    }
+    case StandardOpcodes::ConstAddPc: {
+        u8 adjusted_opcode = 255 - SPECIAL_OPCODES_BASE;
+        ssize_t address_increment = (adjusted_opcode / m_unit_header.line_range) * m_unit_header.min_instruction_length;
+        address_increment *= m_unit_header.min_instruction_length;
+#ifdef DWARF_DEBUG
+        dbgln("ConstAddPc: advance pc by: {} to: {}", address_increment, (m_address + address_increment));
+#endif
+        m_address += address_increment;
+        break;
+    }
+    case StandardOpcodes::SetIsa: {
+        size_t isa;
+        m_stream.read_LEB128_unsigned(isa);
+        dbgln("SetIsa: {}", isa);
+        break;
+    }
+    default:
+        dbgln("Unhandled LineProgram opcode {}", opcode);
+        ASSERT_NOT_REACHED();
+    }
+}
+void LineProgram::handle_sepcial_opcode(u8 opcode)
+{
+    u8 adjusted_opcode = opcode - SPECIAL_OPCODES_BASE;
+    ssize_t address_increment = (adjusted_opcode / m_unit_header.line_range) * m_unit_header.min_instruction_length;
+    ssize_t line_increment = m_unit_header.line_base + (adjusted_opcode % m_unit_header.line_range);
+
+    m_address += address_increment;
+    m_line += line_increment;
+
+#ifdef DWARF_DEBUG
+    dbgln("Special adjusted_opcode: {}, address_increment: {}, line_increment: {}", adjusted_opcode, address_increment, line_increment);
+    dbg() << "Address is now:" << (void*)m_address << ", and line is: " << m_source_files[m_file_index].name << ":" << m_line;
+#endif
+
+    append_to_line_info();
+}
+
+void LineProgram::run_program()
+{
+    reset_registers();
+
+    while ((size_t)m_stream.offset() < m_unit_offset + sizeof(u32) + m_unit_header.length) {
+        u8 opcode = 0;
+        m_stream >> opcode;
+
+#ifdef DWARF_DEBUG
+        dbg() << (void*)(m_stream.offset() - 1) << ": opcode: " << opcode;
+#endif
+
+        if (opcode == 0) {
+            handle_extended_opcode();
+        } else if (opcode >= 1 && opcode <= 12) {
+            handle_standard_opcode(opcode);
+        } else {
+            handle_sepcial_opcode(opcode);
+        }
+    }
+}
+
+}