From d295095993f5896674995d62319b11dcf2785597 Mon Sep 17 00:00:00 2001
From: FalseHonesty <thefalsehonesty@gmail.com>
Date: Mon, 12 Apr 2021 01:30:57 -0400
Subject: [PATCH] LibDebug+HackStudio: Fix crashes relating to debugger
 variable preview

For one, viewing a variable who's type contained a subprogram will
no longer crash HackStudio. Additionally, the variable view will
handle invalid enum values gracefully now, fixing another crash.
Finally, deeply nested (nest count > 1) structures will have their
memory addresses properly set, fixing the final crash I found.
---
 .../HackStudio/Debugger/VariablesModel.cpp         |  3 ++-
 Userland/Libraries/LibDebug/DebugInfo.cpp          | 14 +++++++-------
 Userland/Libraries/LibDebug/DebugInfo.h            |  2 +-
 3 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/Userland/DevTools/HackStudio/Debugger/VariablesModel.cpp b/Userland/DevTools/HackStudio/Debugger/VariablesModel.cpp
index e010fa997c..973a2e91a3 100644
--- a/Userland/DevTools/HackStudio/Debugger/VariablesModel.cpp
+++ b/Userland/DevTools/HackStudio/Debugger/VariablesModel.cpp
@@ -83,7 +83,8 @@ static String variable_value_as_string(const Debug::DebugInfo::VariableInfo& var
         auto it = variable.type->members.find_if([&enumerator_value = value.value()](const auto& enumerator) {
             return enumerator->constant_data.as_u32 == enumerator_value;
         });
-        VERIFY(!it.is_end());
+        if (it.is_end())
+            return String::formatted("Unknown ({})", value.value());
         return String::formatted("{}::{}", variable.type_name, (*it)->name);
     }
 
diff --git a/Userland/Libraries/LibDebug/DebugInfo.cpp b/Userland/Libraries/LibDebug/DebugInfo.cpp
index eb8ab79f14..4e6aae944a 100644
--- a/Userland/Libraries/LibDebug/DebugInfo.cpp
+++ b/Userland/Libraries/LibDebug/DebugInfo.cpp
@@ -252,7 +252,7 @@ static void parse_variable_location(const Dwarf::DIE& variable_die, DebugInfo::V
     }
 }
 
-OwnPtr<DebugInfo::VariableInfo> DebugInfo::create_variable_info(const Dwarf::DIE& variable_die, const PtraceRegisters& regs) const
+OwnPtr<DebugInfo::VariableInfo> DebugInfo::create_variable_info(const Dwarf::DIE& variable_die, const PtraceRegisters& regs, u32 address_offset) const
 {
     VERIFY(variable_die.tag() == Dwarf::EntryTag::Variable
         || variable_die.tag() == Dwarf::EntryTag::Member
@@ -290,6 +290,7 @@ OwnPtr<DebugInfo::VariableInfo> DebugInfo::create_variable_info(const Dwarf::DIE
         }
     } else {
         parse_variable_location(variable_die, *variable_info, regs);
+        variable_info->location_data.address += address_offset;
     }
 
     if (type_die.has_value()) {
@@ -301,21 +302,20 @@ OwnPtr<DebugInfo::VariableInfo> DebugInfo::create_variable_info(const Dwarf::DIE
         type_die.value().for_each_child([&](const Dwarf::DIE& member) {
             if (member.is_null())
                 return;
-            auto member_variable = create_variable_info(member, regs);
+            if (member.tag() == Dwarf::EntryTag::SubProgram)
+                return;
+
+            auto member_variable = create_variable_info(member, regs, variable_info->location_data.address);
             VERIFY(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 {
-                if (variable_info->location_type == DebugInfo::VariableInfo::LocationType::None) {
+                if (variable_info->location_type == DebugInfo::VariableInfo::LocationType::None)
                     return;
-                }
                 VERIFY(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());
             }
diff --git a/Userland/Libraries/LibDebug/DebugInfo.h b/Userland/Libraries/LibDebug/DebugInfo.h
index 8c73d7dee4..4c1372d9c2 100644
--- a/Userland/Libraries/LibDebug/DebugInfo.h
+++ b/Userland/Libraries/LibDebug/DebugInfo.h
@@ -140,7 +140,7 @@ private:
     void prepare_variable_scopes();
     void prepare_lines();
     void parse_scopes_impl(const Dwarf::DIE& die);
-    OwnPtr<VariableInfo> create_variable_info(const Dwarf::DIE& variable_die, const PtraceRegisters&) const;
+    OwnPtr<VariableInfo> create_variable_info(const Dwarf::DIE& variable_die, const PtraceRegisters&, u32 address_offset = 0) const;
 
     NonnullOwnPtr<const ELF::Image> m_elf;
     String m_source_root;