LibDebug: Implement support for DWARF 5 line programs

Userland/Libraries/LibDebug/DebugInfo.cpp

@@ -92,7 +92,7 @@ void DebugInfo::prepare_lines()
 
     Vector<Dwarf::LineProgram::LineInfo> all_lines;
     while (!stream.eof()) {
-        Dwarf::LineProgram program(stream);
+        Dwarf::LineProgram program(m_dwarf_info, stream);
         all_lines.append(program.lines());
     }
 

Userland/Libraries/LibDebug/Dwarf/LineProgram.cpp

@@ -6,13 +6,15 @@
 
 #include "LineProgram.h"
 #include <AK/Debug.h>
+#include <AK/Function.h>
 #include <AK/String.h>
 #include <AK/StringBuilder.h>
 
 namespace Debug::Dwarf {
 
-LineProgram::LineProgram(InputMemoryStream& stream)
-    : m_stream(stream)
+LineProgram::LineProgram(DwarfInfo& dwarf_info, InputMemoryStream& stream)
+    : m_dwarf_info(dwarf_info)
+    , m_stream(stream)
 {
     m_unit_offset = m_stream.offset();
     parse_unit_header();
@@ -23,45 +25,100 @@ LineProgram::LineProgram(InputMemoryStream& stream)
 
 void LineProgram::parse_unit_header()
 {
-    m_stream >> Bytes { &m_unit_header, sizeof(m_unit_header) };
+    m_stream >> m_unit_header;
 
-    VERIFY(m_unit_header.version == DWARF_VERSION);
-    VERIFY(m_unit_header.opcode_base == SPECIAL_OPCODES_BASE);
+    VERIFY(m_unit_header.version() >= MIN_DWARF_VERSION && m_unit_header.version() <= MAX_DWARF_VERSION);
+    VERIFY(m_unit_header.opcode_base() <= sizeof(m_unit_header.std_opcode_lengths) / sizeof(m_unit_header.std_opcode_lengths[0]) + 1);
 
-    dbgln_if(DWARF_DEBUG, "unit length: {}", m_unit_header.length);
+    dbgln_if(DWARF_DEBUG, "unit length: {}", m_unit_header.length());
 }
 
-void LineProgram::parse_source_directories()
+void LineProgram::parse_path_entries(Function<void(PathEntry& entry)> callback, PathListType list_type)
 {
-    m_source_directories.append(".");
+    if (m_unit_header.version() >= 5) {
+        u8 path_entry_format_count = 0;
+        m_stream >> path_entry_format_count;
+
+        Vector<PathEntryFormat> format_descriptions;
+
+        for (u8 i = 0; i < path_entry_format_count; i++) {
+            size_t content_type = 0;
+            m_stream.read_LEB128_unsigned(content_type);
+
+            size_t data_form = 0;
+            m_stream.read_LEB128_unsigned(data_form);
+
+            format_descriptions.empend((ContentType)content_type, (AttributeDataForm)data_form);
+        }
 
-    while (m_stream.peek_or_error()) {
-        String directory;
-        m_stream >> directory;
-        dbgln_if(DWARF_DEBUG, "directory: {}", directory);
-        m_source_directories.append(move(directory));
+        size_t paths_count = 0;
+        m_stream.read_LEB128_unsigned(paths_count);
+
+        for (size_t i = 0; i < paths_count; i++) {
+            PathEntry entry;
+            for (auto& format_description : format_descriptions) {
+                auto value = m_dwarf_info.get_attribute_value(format_description.form, m_stream);
+                switch (format_description.type) {
+                case ContentType::Path:
+                    entry.path = value.data.as_string;
+                    break;
+                case ContentType::DirectoryIndex:
+                    entry.directory_index = value.data.as_u32;
+                    break;
+                default:
+                    dbgln_if(DWARF_DEBUG, "Unhandled path list attribute: {}", (int)format_description.type);
+                }
+            }
+            callback(entry);
+        }
+    } else {
+        while (m_stream.peek_or_error()) {
+            String path;
+            m_stream >> path;
+            dbgln_if(DWARF_DEBUG, "path: {}", path);
+            PathEntry entry;
+            entry.path = path;
+            if (list_type == PathListType::Filenames) {
+                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
+                entry.directory_index = directory_index;
+                dbgln_if(DWARF_DEBUG, "file: {}, directory index: {}", path, directory_index);
+            }
+            callback(entry);
+        }
+
+        m_stream.handle_recoverable_error();
+        m_stream.discard_or_error(1);
     }
-    m_stream.handle_recoverable_error();
-    m_stream.discard_or_error(1);
+
     VERIFY(!m_stream.has_any_error());
 }
 
+void LineProgram::parse_source_directories()
+{
+    if (m_unit_header.version() < 5) {
+        m_source_directories.append(".");
+    }
+
+    parse_path_entries([this](PathEntry& entry) {
+        m_source_directories.append(entry.path);
+    },
+        PathListType::Directories);
+}
+
 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
-        dbgln_if(DWARF_DEBUG, "file: {}, directory index: {}", file_name, directory_index);
-        m_source_files.append({ file_name, directory_index });
-    }
-    m_stream.discard_or_error(1);
-    VERIFY(!m_stream.has_any_error());
+    if (m_unit_header.version() < 5) {
+        m_source_files.append({ ".", 0 });
+    }
+
+    parse_path_entries([this](PathEntry& entry) {
+        m_source_files.append({ entry.path, entry.directory_index });
+    },
+        PathListType::Filenames);
 }
 
 void LineProgram::append_to_line_info()
@@ -88,7 +145,7 @@ void LineProgram::reset_registers()
     m_address = 0;
     m_line = 1;
     m_file_index = 1;
-    m_is_statement = m_unit_header.default_is_stmt == 1;
+    m_is_statement = m_unit_header.default_is_stmt() == 1;
 }
 
 void LineProgram::handle_extended_opcode()
@@ -131,7 +188,7 @@ void LineProgram::handle_standard_opcode(u8 opcode)
     case StandardOpcodes::AdvancePc: {
         size_t operand = 0;
         m_stream.read_LEB128_unsigned(operand);
-        size_t delta = operand * m_unit_header.min_instruction_length;
+        size_t delta = operand * m_unit_header.min_instruction_length();
         dbgln_if(DWARF_DEBUG, "AdvancePC by: {} to: {:p}", delta, m_address + delta);
         m_address += delta;
         break;
@@ -165,9 +222,9 @@ void LineProgram::handle_standard_opcode(u8 opcode)
         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;
+        u8 adjusted_opcode = 255 - m_unit_header.opcode_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();
         dbgln_if(DWARF_DEBUG, "ConstAddPc: advance pc by: {} to: {}", address_increment, (m_address + address_increment));
         m_address += address_increment;
         break;
@@ -192,9 +249,9 @@ void LineProgram::handle_standard_opcode(u8 opcode)
 }
 void LineProgram::handle_special_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);
+    u8 adjusted_opcode = opcode - m_unit_header.opcode_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;
@@ -211,7 +268,7 @@ void LineProgram::run_program()
 {
     reset_registers();
 
-    while ((size_t)m_stream.offset() < m_unit_offset + sizeof(u32) + m_unit_header.length) {
+    while ((size_t)m_stream.offset() < m_unit_offset + sizeof(u32) + m_unit_header.length()) {
         u8 opcode = 0;
         m_stream >> opcode;
 

Userland/Libraries/LibDebug/Dwarf/LineProgram.h

@@ -6,27 +6,104 @@
 
 #pragma once
 
+#include "DwarfInfo.h"
 #include <AK/FlyString.h>
 #include <AK/MemoryStream.h>
 #include <AK/Vector.h>
 
 namespace Debug::Dwarf {
 
-struct [[gnu::packed]] LineProgramUnitHeader32 {
+struct [[gnu::packed]] LineProgramUnitHeader32Common {
     u32 length;
     u16 version;
+};
+
+struct [[gnu::packed]] LineProgramUnitHeader32V4Ext {
+    u32 header_length;
+    u8 min_instruction_length;
+    u8 max_instruction_length;
+    u8 default_is_stmt;
+    i8 line_base;
+    u8 line_range;
+    u8 opcode_base;
+};
+
+struct [[gnu::packed]] LineProgramUnitHeader32V5Ext {
+    u8 address_size;
+    u8 segment_selector_size;
     u32 header_length;
     u8 min_instruction_length;
+    u8 max_instruction_length;
     u8 default_is_stmt;
     i8 line_base;
     u8 line_range;
     u8 opcode_base;
-    u8 std_opcode_lengths[12];
 };
 
+struct [[gnu::packed]] LineProgramUnitHeader32 {
+    LineProgramUnitHeader32Common common;
+
+    union {
+        LineProgramUnitHeader32V4Ext v4;
+        LineProgramUnitHeader32V5Ext v5;
+    };
+
+    u8 std_opcode_lengths[13];
+
+    size_t header_size() const
+    {
+        return sizeof(common) + ((common.version <= 4) ? sizeof(v4) : sizeof(v5)) + (opcode_base() - 1) * sizeof(std_opcode_lengths[0]);
+    }
+
+    u32 length() const { return common.length; }
+    u16 version() const { return common.version; }
+    u32 header_length() const { return (common.version <= 4) ? v4.header_length : v5.header_length; }
+    u8 min_instruction_length() const { return (common.version <= 4) ? v4.min_instruction_length : v5.min_instruction_length; }
+    u8 default_is_stmt() const { return (common.version <= 4) ? v4.default_is_stmt : v5.default_is_stmt; }
+    i8 line_base() const { return (common.version <= 4) ? v4.line_base : v5.line_base; }
+    u8 line_range() const { return (common.version <= 4) ? v4.line_range : v5.line_range; }
+    u8 opcode_base() const { return (common.version <= 4) ? v4.opcode_base : v5.opcode_base; }
+};
+
+enum class ContentType {
+    Path = 1,
+    DirectoryIndex = 2,
+    Timestamp = 3,
+    Size = 4,
+    MD5 = 5,
+    LoUser = 0x2000,
+    HiUser = 0x3fff,
+};
+
+struct PathEntryFormat {
+    ContentType type;
+    AttributeDataForm form;
+};
+
+struct PathEntry {
+    String path;
+    size_t directory_index { 0 };
+};
+
+enum class PathListType {
+    Directories,
+    Filenames,
+};
+
+inline InputStream& operator>>(InputStream& stream, LineProgramUnitHeader32& header)
+{
+    stream.read_or_error(Bytes { &header.common, sizeof(header.common) });
+    if (header.common.version <= 4)
+        stream.read_or_error(Bytes { &header.v4, sizeof(header.v4) });
+    else
+        stream.read_or_error(Bytes { &header.v5, sizeof(header.v5) });
+    stream.read_or_error(Bytes { &header.std_opcode_lengths, min(sizeof(header.std_opcode_lengths), (header.opcode_base() - 1) * sizeof(header.std_opcode_lengths[0])) });
+    return stream;
+}
+
 class LineProgram {
 public:
-    explicit LineProgram(InputMemoryStream& stream);
+    explicit LineProgram(DwarfInfo& dwarf_info, InputMemoryStream& stream);
 
     struct LineInfo {
         u32 address { 0 };
@@ -49,6 +126,8 @@ private:
     void handle_standard_opcode(u8 opcode);
     void handle_special_opcode(u8 opcode);
 
+    void parse_path_entries(Function<void(PathEntry& entry)> callback, PathListType list_type);
+
     enum StandardOpcodes {
         Copy = 1,
         AdvancePc,
@@ -76,9 +155,10 @@ private:
         size_t directory_index { 0 };
     };
 
-    static constexpr u16 DWARF_VERSION = 3;
-    static constexpr u8 SPECIAL_OPCODES_BASE = 13;
+    static constexpr u16 MIN_DWARF_VERSION = 3;
+    static constexpr u16 MAX_DWARF_VERSION = 5;
 
+    DwarfInfo& m_dwarf_info;
     InputMemoryStream& m_stream;
 
     size_t m_unit_offset { 0 };