LibDebug: Don't assume compilation unit index == line program index

Instead, use the `DW_AT_stmt_list` attribute of the compilation unit entry to determine the corresponding line program.
danyreyna · May 7, 2024 · 116f82d · 116f82d
1 parent 14ae040
commit 116f82d
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Showing 3 changed files with 34 additions and 21 deletions.
diff --git a/Userland/Libraries/LibDebug/Dwarf/CompilationUnit.cpp b/Userland/Libraries/LibDebug/Dwarf/CompilationUnit.cpp
@@ -6,22 +6,46 @@
 
 #include "CompilationUnit.h"
 #include <AK/ByteReader.h>
+#include <AK/MemoryStream.h>
 #include <LibDebug/Dwarf/DIE.h>
 #include <LibDebug/Dwarf/DwarfInfo.h>
 #include <LibDebug/Dwarf/LineProgram.h>
 
 namespace Debug::Dwarf {
 
-CompilationUnit::CompilationUnit(DwarfInfo const& dwarf_info, u32 offset, CompilationUnitHeader const& header, NonnullOwnPtr<LineProgram>&& line_program)
+CompilationUnit::CompilationUnit(DwarfInfo const& dwarf_info, u32 offset, CompilationUnitHeader const& header)
     : m_dwarf_info(dwarf_info)
     , m_offset(offset)
     , m_header(header)
     , m_abbreviations(dwarf_info, header.abbrev_offset())
-    , m_line_program(move(line_program))
 {
     VERIFY(header.version() < 5 || header.unit_type() == CompilationUnitType::Full);
 }
 
+ErrorOr<NonnullOwnPtr<CompilationUnit>> CompilationUnit::create(DwarfInfo const& dwarf_info, u32 offset, CompilationUnitHeader const& header, ReadonlyBytes debug_line_data)
+{
+    auto compilation_unit = TRY(adopt_nonnull_own_or_enomem(new (nothrow) CompilationUnit(dwarf_info, offset, header)));
+    TRY(compilation_unit->populate_line_program(debug_line_data));
+    return compilation_unit;
+}
+
+ErrorOr<void> CompilationUnit::populate_line_program(ReadonlyBytes debug_line_data)
+{
+    auto die = root_die();
+
+    auto res = TRY(die.get_attribute(Attribute::StmtList));
+    if (!res.has_value())
+        return EINVAL;
+    VERIFY(res->form() == AttributeDataForm::SecOffset);
+
+    FixedMemoryStream debug_line_stream { debug_line_data };
+    TRY(debug_line_stream.seek(res->as_unsigned()));
+
+    m_line_program = TRY(LineProgram::create(m_dwarf_info, debug_line_stream));
+
+    return {};
+}
+
 CompilationUnit::~CompilationUnit() = default;
 
 DIE CompilationUnit::root_die() const

diff --git a/Userland/Libraries/LibDebug/Dwarf/CompilationUnit.h b/Userland/Libraries/LibDebug/Dwarf/CompilationUnit.h
@@ -8,7 +8,7 @@
 
 #include "AbbreviationsMap.h"
 #include <AK/Noncopyable.h>
-#include <AK/NonnullOwnPtr.h>
+#include <AK/OwnPtr.h>
 #include <AK/Types.h>
 
 namespace Debug::Dwarf {
@@ -22,7 +22,7 @@ class CompilationUnit {
     AK_MAKE_NONMOVABLE(CompilationUnit);
 
 public:
-    CompilationUnit(DwarfInfo const& dwarf_info, u32 offset, CompilationUnitHeader const&, NonnullOwnPtr<LineProgram>&& line_program);
+    static ErrorOr<NonnullOwnPtr<CompilationUnit>> create(DwarfInfo const& dwarf_info, u32 offset, CompilationUnitHeader const&, ReadonlyBytes debug_line_data);
     ~CompilationUnit();
 
     u32 offset() const { return m_offset; }
@@ -49,11 +49,14 @@ class CompilationUnit {
     ErrorOr<u64> range_lists_base() const;
 
 private:
+    CompilationUnit(DwarfInfo const& dwarf_info, u32 offset, CompilationUnitHeader const&);
+    ErrorOr<void> populate_line_program(ReadonlyBytes debug_line_data);
+
     DwarfInfo const& m_dwarf_info;
     u32 m_offset { 0 };
     CompilationUnitHeader m_header;
     AbbreviationsMap m_abbreviations;
-    NonnullOwnPtr<LineProgram> m_line_program;
+    OwnPtr<LineProgram> m_line_program;
     mutable bool m_has_cached_base_address : 1 { false };
     mutable bool m_has_cached_address_table_base : 1 { false };
     mutable bool m_has_cached_string_offsets_base : 1 { false };

diff --git a/Userland/Libraries/LibDebug/Dwarf/DwarfInfo.cpp b/Userland/Libraries/LibDebug/Dwarf/DwarfInfo.cpp
@@ -48,7 +48,6 @@ ErrorOr<void> DwarfInfo::populate_compilation_units()
         return {};
 
     FixedMemoryStream debug_info_stream { m_debug_info_data };
-    FixedMemoryStream line_info_stream { m_debug_line_data };
 
     while (!debug_info_stream.is_eof()) {
         auto unit_offset = TRY(debug_info_stream.tell());
@@ -59,23 +58,10 @@ ErrorOr<void> DwarfInfo::populate_compilation_units()
 
         u32 length_after_header = compilation_unit_header.length() - (compilation_unit_header.header_size() - offsetof(CompilationUnitHeader, common.version));
 
-        auto line_program = TRY(LineProgram::create(*this, line_info_stream));
-
-        // HACK: Clang generates line programs for embedded resource assembly files, but not compile units.
-        // Meaning that for graphical applications, some line info data would be unread, triggering the assertion below.
-        // As a fix, we don't create compilation units for line programs that come from resource files.
-#if defined(AK_COMPILER_CLANG)
-        if (line_program->looks_like_embedded_resource()) {
-            TRY(debug_info_stream.seek(unit_offset));
-        } else
-#endif
-        {
-            m_compilation_units.append(make<CompilationUnit>(*this, unit_offset, compilation_unit_header, move(line_program)));
-            TRY(debug_info_stream.discard(length_after_header));
-        }
+        m_compilation_units.append(TRY(CompilationUnit::create(*this, unit_offset, compilation_unit_header, m_debug_line_data)));
+        TRY(debug_info_stream.discard(length_after_header));
     }
 
-    VERIFY(line_info_stream.is_eof());
     return {};
 }