LibDebug: Add support for enum value types

Additionally, we will parse and expose the types of variables
if they are complex, like Enums or Structs. Variables of an enum
type are special in that they do not store all the members of said
enum in their own VariableInfo like Structs do, rather, all of the
values are stored in the VariableInfo for the Enum.

3 files changed, 101 insertions, 35 deletions

diff --git a/Libraries/LibDebug/DebugInfo.cpp b/Libraries/LibDebug/DebugInfo.cpp
index 93dbcf11f2..4bff5b8843 100644
--- a/Libraries/LibDebug/DebugInfo.cpp
+++ b/Libraries/LibDebug/DebugInfo.cpp
@@ -163,43 +163,36 @@ NonnullOwnPtrVector<DebugInfo::VariableInfo> DebugInfo::get_variables_in_current
     return variables;
 }
 
-OwnPtr<DebugInfo::VariableInfo> DebugInfo::create_variable_info(const Dwarf::DIE& variable_die, const PtraceRegisters& regs) const
+static Optional<Dwarf::DIE> parse_variable_type_die(const Dwarf::DIE& variable_die, DebugInfo::VariableInfo& variable_info)
 {
-    ASSERT(variable_die.tag() == Dwarf::EntryTag::Variable
-        || variable_die.tag() == Dwarf::EntryTag::Member
-        || variable_die.tag() == Dwarf::EntryTag::FormalParameter);
-
-    if (variable_die.tag() == Dwarf::EntryTag::FormalParameter
-        && !variable_die.get_attribute(Dwarf::Attribute::Name).has_value()) {
-        // We don't want to display info for unused paramters
+    auto type_die_offset = variable_die.get_attribute(Dwarf::Attribute::Type);
+    if (!type_die_offset.has_value())
         return {};
-    }
 
-    NonnullOwnPtr<VariableInfo> variable_info = make<VariableInfo>();
-
-    variable_info->name = variable_die.get_attribute(Dwarf::Attribute::Name).value().data.as_string;
-    auto type_die_offset = variable_die.get_attribute(Dwarf::Attribute::Type);
-    ASSERT(type_die_offset.has_value());
     ASSERT(type_die_offset.value().type == Dwarf::DIE::AttributeValue::Type::DieReference);
 
     auto type_die = variable_die.get_die_at_offset(type_die_offset.value().data.as_u32);
     auto type_name = type_die.get_attribute(Dwarf::Attribute::Name);
     if (type_name.has_value()) {
-        variable_info->type = type_name.value().data.as_string;
+        variable_info.type_name = type_name.value().data.as_string;
     } else {
         dbg() << "Unnamed DWARF type at offset: " << type_die.offset();
-        variable_info->name = "[Unnamed Type]";
+        variable_info.name = "[Unnamed Type]";
     }
 
+    return type_die;
+}
+
+static void parse_variable_location(const Dwarf::DIE& variable_die, DebugInfo::VariableInfo& variable_info, const PtraceRegisters& regs)
+{
     auto location_info = variable_die.get_attribute(Dwarf::Attribute::Location);
-    if (!location_info.has_value()) {
+    if (!location_info.has_value())
         location_info = variable_die.get_attribute(Dwarf::Attribute::MemberLocation);
-    }
 
     if (location_info.has_value()) {
         if (location_info.value().type == Dwarf::DIE::AttributeValue::Type::UnsignedNumber) {
-            variable_info->location_type = VariableInfo::LocationType::Address;
-            variable_info->location_data.address = location_info.value().data.as_u32;
+            variable_info.location_type = DebugInfo::VariableInfo::LocationType::Address;
+            variable_info.location_data.address = location_info.value().data.as_u32;
         }
 
         if (location_info.value().type == Dwarf::DIE::AttributeValue::Type::DwarfExpression) {
@@ -208,26 +201,85 @@ OwnPtr<DebugInfo::VariableInfo> DebugInfo::create_variable_info(const Dwarf::DIE
 
             if (value.type != Dwarf::Expression::Type::None) {
                 ASSERT(value.type == Dwarf::Expression::Type::UnsignedIntetger);
-                variable_info->location_type = VariableInfo::LocationType::Address;
-                variable_info->location_data.address = value.data.as_u32;
+                variable_info.location_type = DebugInfo::VariableInfo::LocationType::Address;
+                variable_info.location_data.address = value.data.as_u32;
             }
         }
     }
+}
 
-    type_die.for_each_child([&](const Dwarf::DIE& member) {
-        if (member.is_null())
-            return;
-        auto member_variable = create_variable_info(member, regs);
+OwnPtr<DebugInfo::VariableInfo> DebugInfo::create_variable_info(const Dwarf::DIE& variable_die, const PtraceRegisters& regs) const
+{
+    ASSERT(variable_die.tag() == Dwarf::EntryTag::Variable
+        || variable_die.tag() == Dwarf::EntryTag::Member
+        || variable_die.tag() == Dwarf::EntryTag::FormalParameter
+        || variable_die.tag() == Dwarf::EntryTag::EnumerationType
+        || variable_die.tag() == Dwarf::EntryTag::Enumerator
+        || variable_die.tag() == Dwarf::EntryTag::StructureType);
 
-        ASSERT(member_variable);
-        ASSERT(member_variable->location_type == DebugInfo::VariableInfo::LocationType::Address);
-        ASSERT(variable_info->location_type == DebugInfo::VariableInfo::LocationType::Address);
+    if (variable_die.tag() == Dwarf::EntryTag::FormalParameter
+        && !variable_die.get_attribute(Dwarf::Attribute::Name).has_value()) {
+        // We don't want to display info for unused paramters
+        return {};
+    }
+
+    NonnullOwnPtr<VariableInfo> variable_info = make<VariableInfo>();
+    variable_info->name = variable_die.get_attribute(Dwarf::Attribute::Name).value().data.as_string;
 
-        member_variable->location_data.address += variable_info->location_data.address;
-        member_variable->parent = variable_info.ptr();
+    auto type_die = parse_variable_type_die(variable_die, *variable_info);
+
+    if (variable_die.tag() == Dwarf::EntryTag::Enumerator) {
+        auto constant = variable_die.get_attribute(Dwarf::Attribute::ConstValue);
+        ASSERT(constant.has_value());
+        switch (constant.value().type) {
+        case Dwarf::DIE::AttributeValue::Type::UnsignedNumber:
+            variable_info->constant_data.as_u32 = constant.value().data.as_u32;
+            break;
+        case Dwarf::DIE::AttributeValue::Type::SignedNumber:
+            variable_info->constant_data.as_i32 = constant.value().data.as_i32;
+            break;
+        case Dwarf::DIE::AttributeValue::Type::String:
+            variable_info->constant_data.as_string = constant.value().data.as_string;
+            break;
+        default:
+            ASSERT_NOT_REACHED();
+        }
+    } else {
+        parse_variable_location(variable_die, *variable_info, regs);
+    }
 
-        variable_info->members.append(member_variable.release_nonnull());
-    });
+    if (type_die.has_value()) {
+        OwnPtr<VariableInfo> type_info;
+        if (type_die.value().tag() == Dwarf::EntryTag::EnumerationType || type_die.value().tag() == Dwarf::EntryTag::StructureType) {
+            type_info = create_variable_info(type_die.value(), regs);
+        }
+
+        type_die.value().for_each_child([&](const Dwarf::DIE& member) {
+            if (member.is_null())
+                return;
+            auto member_variable = create_variable_info(member, regs);
+
+            ASSERT(member_variable);
+
+            if (type_die.value().tag() == Dwarf::EntryTag::EnumerationType) {
+                member_variable->parent = type_info.ptr();
+                type_info->members.append(member_variable.release_nonnull());
+            } else {
+                ASSERT(variable_info->location_type == DebugInfo::VariableInfo::LocationType::Address);
+
+                if (member_variable->location_type == DebugInfo::VariableInfo::LocationType::Address)
+                    member_variable->location_data.address += variable_info->location_data.address;
+
+                member_variable->parent = variable_info.ptr();
+                variable_info->members.append(member_variable.release_nonnull());
+            }
+        });
+
+        if (type_info) {
+            variable_info->type = move(type_info);
+            variable_info->type->type_tag = type_die.value().tag();
+        }
+    }
 
     return variable_info;
 }
diff --git a/Libraries/LibDebug/DebugInfo.h b/Libraries/LibDebug/DebugInfo.h
index de73a8aa38..d73582c7fb 100644
--- a/Libraries/LibDebug/DebugInfo.h
+++ b/Libraries/LibDebug/DebugInfo.h
@@ -53,17 +53,27 @@ public:
         enum class LocationType {
             None,
             Address,
-            Regsiter,
+            Register,
         };
         String name;
-        String type;
+        String type_name;
         LocationType location_type { LocationType::None };
         union {
             u32 address;
         } location_data { 0 };
 
+        union {
+            u32 as_u32;
+            u32 as_i32;
+            const char* as_string;
+        } constant_data { 0 };
+
+        Dwarf::EntryTag type_tag;
+        OwnPtr<VariableInfo> type;
         NonnullOwnPtrVector<VariableInfo> members;
         VariableInfo* parent { nullptr };
+
+        bool is_enum_type() const { return type && type->type_tag == Dwarf::EntryTag::EnumerationType; }
     };
 
     struct VariablesScope {
diff --git a/Libraries/LibDebug/Dwarf/DwarfTypes.h b/Libraries/LibDebug/Dwarf/DwarfTypes.h
index 84f09b6fad..e3f601ab4e 100644
--- a/Libraries/LibDebug/Dwarf/DwarfTypes.h
+++ b/Libraries/LibDebug/Dwarf/DwarfTypes.h
@@ -40,9 +40,12 @@ struct [[gnu::packed]] CompilationUnitHeader
 
 enum class EntryTag : u32 {
     None = 0,
+    EnumerationType = 0x4,
     FormalParameter = 0x5,
     LexicalBlock = 0xb,
     Member = 0xd,
+    StructureType = 0x13,
+    Enumerator = 0x28,
     SubProgram = 0x2e,
     Variable = 0x34,
 };
@@ -54,6 +57,7 @@ enum class Attribute : u32 {
     Name = 0x3,
     LowPc = 0x11,
     HighPc = 0x12,
+    ConstValue = 0x1c,
     Inline = 0x20,
     MemberLocation = 0x38,
     Type = 0x49,