From 104b28862d8432f6e7402f9cb24b48b097318eb7 Mon Sep 17 00:00:00 2001
From: Rene Gollent <anevilyak@gmail.com>
Date: Fri, 19 Jul 2013 21:44:48 -0400
Subject: [PATCH] Debugger: DwarfFile: Fix DWARF4 signature handling.

Depending on how the type unit was actually set up hierarchically,
we sometimes ended up with the unit set to the wrong actual type
object. Instead, we now simply let the unit parse, and then look up
the entry by the offset specified in the header after all is said
and done. Fixes class/struct objects sometimes winding up resolving
to one of their members instead.

Some problems still remain with resolving variable values for such
types though, needs further investigation.
---
 src/apps/debugger/dwarf/DebugInfoEntries.cpp | 10 ----------
 src/apps/debugger/dwarf/DebugInfoEntries.h   |  5 -----
 src/apps/debugger/dwarf/DwarfFile.cpp        |  8 ++++++++
 src/apps/debugger/dwarf/TypeUnit.cpp         | 11 ++++++++---
 src/apps/debugger/dwarf/TypeUnit.h           |  2 ++
 5 files changed, 18 insertions(+), 18 deletions(-)

diff --git a/src/apps/debugger/dwarf/DebugInfoEntries.cpp b/src/apps/debugger/dwarf/DebugInfoEntries.cpp
index b4f620a1bc..93ff1dc999 100644
--- a/src/apps/debugger/dwarf/DebugInfoEntries.cpp
+++ b/src/apps/debugger/dwarf/DebugInfoEntries.cpp
@@ -2549,16 +2549,6 @@ DIETypeUnit::Tag() const
 }
 
 
-status_t
-DIETypeUnit::AddChild(DebugInfoEntry* child)
-{
-	if (child->IsType())
-		fType = dynamic_cast<DIEType*>(child);
-
-	return B_OK;
-}
-
-
 status_t
 DIETypeUnit::AddAttribute_language(uint16 attributeName,
 	const AttributeValue& value)
diff --git a/src/apps/debugger/dwarf/DebugInfoEntries.h b/src/apps/debugger/dwarf/DebugInfoEntries.h
index 6fffdf4176..66b481883c 100644
--- a/src/apps/debugger/dwarf/DebugInfoEntries.h
+++ b/src/apps/debugger/dwarf/DebugInfoEntries.h
@@ -1614,16 +1614,11 @@ public:
 
 			uint16				Language() const	{ return fLanguage; }
 
-	virtual	status_t			AddChild(DebugInfoEntry* child);
-
 	virtual	status_t			AddAttribute_language(uint16 attributeName,
 									const AttributeValue& value);
-	inline	DIEType*			GetType() const { return fType; }
-
 
 private:
 			uint16				fLanguage;
-			DIEType*			fType;
 };
 
 
diff --git a/src/apps/debugger/dwarf/DwarfFile.cpp b/src/apps/debugger/dwarf/DwarfFile.cpp
index fd2c8531fa..66b9c41f5e 100644
--- a/src/apps/debugger/dwarf/DwarfFile.cpp
+++ b/src/apps/debugger/dwarf/DwarfFile.cpp
@@ -1142,6 +1142,13 @@ DwarfFile::_ParseTypeUnit(TypeUnit* unit)
 	}
 
 	unit->SetUnitEntry(unitEntry);
+	DebugInfoEntry* typeEntry = unit->EntryForOffset(unit->TypeOffset());
+	if (typeEntry == NULL) {
+		WARNING("No type found for type unit %p at specified offset %"
+			B_PRId64 ".\n", unit, unit->TypeOffset());
+		return B_BAD_DATA;
+	}
+	unit->SetTypeEntry(typeEntry);
 
 	TRACE_DIE_ONLY(
 		TRACE_DIE("remaining bytes in unit: %" B_PRIdOFF "\n",
@@ -2591,6 +2598,7 @@ DwarfFile::_ResolveReference(BaseUnit* unit, uint64 offset,
 		}
 		case dwarf_reference_type_signature:
 		{
+			TRACE_DIE("Resolving signature %#" B_PRIx64 "\n", offset);
 			TypeUnitTableEntry* entry = fTypeUnits.Lookup(offset);
 			if (entry != NULL && entry->unit != NULL)
 				return entry->unit->TypeEntry();
diff --git a/src/apps/debugger/dwarf/TypeUnit.cpp b/src/apps/debugger/dwarf/TypeUnit.cpp
index 0a3af5d85a..6dd4113bd6 100644
--- a/src/apps/debugger/dwarf/TypeUnit.cpp
+++ b/src/apps/debugger/dwarf/TypeUnit.cpp
@@ -16,6 +16,7 @@ TypeUnit::TypeUnit(off_t headerOffset, off_t contentOffset,
 	BaseUnit(headerOffset, contentOffset, totalSize, abbreviationOffset,
 		addressSize, isDwarf64),
 	fUnitEntry(NULL),
+	fTypeEntry(NULL),
 	fSignature(signature),
 	fTypeOffset(typeOffset)
 {
@@ -37,10 +38,14 @@ TypeUnit::SetUnitEntry(DIETypeUnit* entry)
 DebugInfoEntry*
 TypeUnit::TypeEntry() const
 {
-	if (fUnitEntry != NULL)
-		return fUnitEntry->GetType();
+	return fTypeEntry;
+}
 
-	return NULL;
+
+void
+TypeUnit::SetTypeEntry(DebugInfoEntry* entry)
+{
+	fTypeEntry = entry;
 }
 
 
diff --git a/src/apps/debugger/dwarf/TypeUnit.h b/src/apps/debugger/dwarf/TypeUnit.h
index 74664e6491..ee3d594f2b 100644
--- a/src/apps/debugger/dwarf/TypeUnit.h
+++ b/src/apps/debugger/dwarf/TypeUnit.h
@@ -36,11 +36,13 @@ public:
 			void				SetUnitEntry(DIETypeUnit* entry);
 
 			DebugInfoEntry*		TypeEntry() const;
+			void				SetTypeEntry(DebugInfoEntry* entry);
 
 	virtual	dwarf_unit_kind		Kind() const;
 
 private:
 			DIETypeUnit*		fUnitEntry;
+			DebugInfoEntry*		fTypeEntry;
 			uint64				fSignature;
 			off_t				fTypeOffset;
 };