Fix #8508.

- When attempting to unwind the call frame, we now search for the appropriate
  FDE in both .debug_frame and .eh_frame. This mirrors gdb's behavior and
  works around the ever-changing whims of the gcc developers as to which
  section the requisite FDE/CIE resides in.

src/apps/debugger/debug_info/DwarfImageDebugInfo.cpp

@@ -1,5 +1,6 @@
 /*
  * Copyright 2009, Ingo Weinhold, ingo_weinhold@gmx.de.
+ * Copyright 2012, Rene Gollent, rene@gollent.com.
  * Distributed under the terms of the MIT License.
  */
 
@@ -554,8 +555,22 @@ DwarfImageDebugInfo::CreateFrame(Image* image,
 		= cpuState->InstructionPointer() - fRelocationDelta;
 	target_addr_t framePointer;
 	CompilationUnit* unit = function->GetCompilationUnit();
-	error = fFile->UnwindCallFrame(unit, function->SubprogramEntry(),
-		instructionPointer, inputInterface, outputInterface, framePointer);
+	// first try .debug_frame
+	if (fFile->HasDebugFrameSection()) {
+		error = fFile->UnwindCallFrame(false, unit,
+			function->SubprogramEntry(), instructionPointer, inputInterface,
+			outputInterface, framePointer);
+	} else
+		error = B_ENTRY_NOT_FOUND;
+
+	// if that section isn't present, or we couldn't find a match,
+	// try .eh_frame if possible.
+	if (error == B_ENTRY_NOT_FOUND && fFile->HasEHFrameSection()) {
+		error = fFile->UnwindCallFrame(true, unit,
+			function->SubprogramEntry(), instructionPointer, inputInterface,
+			outputInterface, framePointer);
+	}
+
 	if (error != B_OK) {
 		TRACE_CFI("Failed to unwind call frame: %s\n", strerror(error));
 		return B_UNSUPPORTED;

src/apps/debugger/dwarf/DwarfFile.cpp

@@ -1,5 +1,6 @@
 /*
  * Copyright 2009-2010, Ingo Weinhold, ingo_weinhold@gmx.de.
+ * Copyright 2012, Rene Gollent, rene@gollent.com.
  * Distributed under the terms of the MIT License.
  */
 
@@ -287,12 +288,11 @@ DwarfFile::DwarfFile()
 	fDebugRangesSection(NULL),
 	fDebugLineSection(NULL),
 	fDebugFrameSection(NULL),
+	fEHFrameSection(NULL),
 	fDebugLocationSection(NULL),
 	fDebugPublicTypesSection(NULL),
 	fCompilationUnits(20, true),
 	fCurrentCompilationUnit(NULL),
-	fUsingEHFrameSection(false),
-	fGCC4EHFrameSection(false),
 	fFinished(false),
 	fFinishError(B_OK)
 {
@@ -311,6 +311,7 @@ DwarfFile::~DwarfFile()
 		fElfFile->PutSection(fDebugRangesSection);
 		fElfFile->PutSection(fDebugLineSection);
 		fElfFile->PutSection(fDebugFrameSection);
+		fElfFile->PutSection(fEHFrameSection);
 		fElfFile->PutSection(fDebugLocationSection);
 		fElfFile->PutSection(fDebugPublicTypesSection);
 		delete fElfFile;
@@ -350,26 +351,7 @@ DwarfFile::Load(const char* fileName)
 	fDebugRangesSection = fElfFile->GetSection(".debug_ranges");
 	fDebugLineSection = fElfFile->GetSection(".debug_line");
 	fDebugFrameSection = fElfFile->GetSection(".debug_frame");
-	ElfSection* ehFrameSection = fElfFile->GetSection(".eh_frame");
-	if (fDebugFrameSection != NULL && ehFrameSection != NULL) {
-		if (ehFrameSection->Size() > fDebugFrameSection->Size()) {
-			fElfFile->PutSection(fDebugFrameSection);
-			fDebugFrameSection = ehFrameSection;
-			fUsingEHFrameSection = true;
-		} else
-			fElfFile->PutSection(ehFrameSection);
-	} else if (ehFrameSection != NULL) {
-		fDebugFrameSection = ehFrameSection;
-		fUsingEHFrameSection = true;
-	}
-
-	if (fUsingEHFrameSection) {
-		fGCC4EHFrameSection = !fDebugFrameSection->IsWritable();
-			// Crude heuristic for recognizing GCC 4 (Itanium ABI) style
-			// .eh_frame sections. The ones generated by GCC 2 are writable,
-			// the ones generated by GCC 4 aren't.
-	}
-
+	fEHFrameSection = fElfFile->GetSection(".eh_frame");
 	fDebugLocationSection = fElfFile->GetSection(".debug_loc");
 	fDebugPublicTypesSection = fElfFile->GetSection(".debug_pubtypes");
 
@@ -553,18 +535,31 @@ DwarfFile::ResolveRangeList(CompilationUnit* unit, uint64 offset) const
 
 
 status_t
-DwarfFile::UnwindCallFrame(CompilationUnit* unit,
+DwarfFile::UnwindCallFrame(bool usingEHFrameSection, CompilationUnit* unit,
 	DIESubprogram* subprogramEntry, target_addr_t location,
 	const DwarfTargetInterface* inputInterface,
 	DwarfTargetInterface* outputInterface, target_addr_t& _framePointer)
 {
-	if (fDebugFrameSection == NULL)
+	ElfSection* currentFrameSection = (usingEHFrameSection)
+		? fEHFrameSection : fDebugFrameSection;
+
+	if (currentFrameSection == NULL)
 		return B_ENTRY_NOT_FOUND;
 
+	bool gcc4EHFrameSection = false;
+	if (usingEHFrameSection) {
+		gcc4EHFrameSection = !currentFrameSection->IsWritable();
+			// Crude heuristic for recognizing GCC 4 (Itanium ABI) style
+			// .eh_frame sections. The ones generated by GCC 2 are writable,
+			// the ones generated by GCC 4 aren't.
+	}
+
+
+
 	TRACE_CFI("DwarfFile::UnwindCallFrame(%#llx)\n", location);
 
-	DataReader dataReader((uint8*)fDebugFrameSection->Data(),
-		fDebugFrameSection->Size(), unit->AddressSize());
+	DataReader dataReader((uint8*)currentFrameSection->Data(),
+		currentFrameSection->Size(), unit->AddressSize());
 
 	while (dataReader.BytesRemaining() > 0) {
 		// length
@@ -584,7 +579,7 @@ DwarfFile::UnwindCallFrame(CompilationUnit* unit,
 			? dataReader.Read<uint64>(0) : dataReader.Read<uint32>(0);
 
 		// In .debug_frame ~0 indicates a CIE, in .eh_frame 0 does.
-		if (fUsingEHFrameSection
+		if (usingEHFrameSection
 			? cieID == 0
 			: (dwarf64
 				? cieID == 0xffffffffffffffffULL
@@ -601,16 +596,16 @@ DwarfFile::UnwindCallFrame(CompilationUnit* unit,
 
 			// In the GCC 4 .eh_frame initialLocation is relative to the offset
 			// of the address.
-			if (fUsingEHFrameSection && fGCC4EHFrameSection) {
+			if (usingEHFrameSection && gcc4EHFrameSection) {
 				// Note: We need to cast to the exact address width, since the
 				// initialLocation value can be (and likely is) negative.
 				if (dwarf64) {
-					initialLocation = (uint64)fDebugFrameSection->LoadAddress()
-						+ (uint64)initialLocationOffset
+					initialLocation = (uint64)currentFrameSection
+						->LoadAddress()	+ (uint64)initialLocationOffset
 						+ (uint64)initialLocation;
 				} else {
-					initialLocation = (uint32)fDebugFrameSection->LoadAddress()
-						+ (uint32)initialLocationOffset
+					initialLocation = (uint32)currentFrameSection
+						->LoadAddress()	+ (uint32)initialLocationOffset
 						+ (uint32)initialLocation;
 				}
 			}
@@ -634,7 +629,7 @@ DwarfFile::UnwindCallFrame(CompilationUnit* unit,
 					return B_BAD_DATA;
 
 				// In .eh_frame the CIE offset is a relative back offset.
-				if (fUsingEHFrameSection) {
+				if (usingEHFrameSection) {
 					if (cieID > (uint64)lengthOffset) {
 						TRACE_CFI("Invalid CIE offset: %" B_PRIu64 ", max "
 							"possible: %" B_PRIu64 "\n", cieID, lengthOffset);
@@ -660,7 +655,8 @@ DwarfFile::UnwindCallFrame(CompilationUnit* unit,
 
 				// process the CIE
 				CIEAugmentation cieAugmentation;
-				error = _ParseCIE(unit, context, cieID, cieAugmentation);
+				error = _ParseCIE(currentFrameSection, usingEHFrameSection,
+					unit, context, cieID, cieAugmentation);
 				if (error != B_OK)
 					return error;
 
@@ -1554,14 +1550,15 @@ DwarfFile::_ParseLineInfo(CompilationUnit* unit)
 
 
 status_t
-DwarfFile::_ParseCIE(CompilationUnit* unit, CfaContext& context,
-	off_t cieOffset, CIEAugmentation& cieAugmentation)
+DwarfFile::_ParseCIE(ElfSection* debugFrameSection, bool usingEHFrameSection,
+	CompilationUnit* unit, CfaContext& context,	off_t cieOffset,
+	CIEAugmentation& cieAugmentation)
 {
-	if (cieOffset < 0 || cieOffset >= fDebugFrameSection->Size())
+	if (cieOffset < 0 || cieOffset >= debugFrameSection->Size())
 		return B_BAD_DATA;
 
-	DataReader dataReader((uint8*)fDebugFrameSection->Data() + cieOffset,
-		fDebugFrameSection->Size() - cieOffset, unit->AddressSize());
+	DataReader dataReader((uint8*)debugFrameSection->Data() + cieOffset,
+		debugFrameSection->Size() - cieOffset, unit->AddressSize());
 
 	// length
 	bool dwarf64;
@@ -1573,7 +1570,7 @@ DwarfFile::_ParseCIE(CompilationUnit* unit, CfaContext& context,
 	// CIE ID/CIE pointer
 	uint64 cieID = dwarf64
 		? dataReader.Read<uint64>(0) : dataReader.Read<uint32>(0);
-	if (fUsingEHFrameSection) {
+	if (usingEHFrameSection) {
 		if (cieID != 0)
 			return B_BAD_DATA;
 	} else {

src/apps/debugger/dwarf/DwarfFile.h

@@ -1,5 +1,6 @@
 /*
  * Copyright 2009-2010, Ingo Weinhold, ingo_weinhold@gmx.de.
+ * Copyright 2012, Rene Gollent, rene@gollent.com.
  * Distributed under the terms of the MIT License.
  */
 #ifndef DWARF_FILE_H
@@ -38,6 +39,13 @@ public:
 			const char*			Name() const		{ return fName; }
 			ElfFile*			GetElfFile() const	{ return fElfFile; }
 
+			bool				HasDebugFrameSection() const {
+									return fDebugFrameSection != NULL;
+								}
+			bool				HasEHFrameSection() const {
+									return fEHFrameSection != NULL;
+								}
+
 			int32				CountCompilationUnits() const;
 			CompilationUnit*	CompilationUnitAt(int32 index) const;
 			CompilationUnit*	CompilationUnitForDIE(
@@ -46,7 +54,8 @@ public:
 			TargetAddressRangeList* ResolveRangeList(CompilationUnit* unit,
 									uint64 offset) const;
 
-			status_t			UnwindCallFrame(CompilationUnit* unit,
+			status_t			UnwindCallFrame(bool usingEHFrameSection,
+									CompilationUnit* unit,
 									DIESubprogram* subprogramEntry,
 									target_addr_t location,
 									const DwarfTargetInterface* inputInterface,
@@ -112,7 +121,9 @@ private:
 
 			status_t			_ParseLineInfo(CompilationUnit* unit);
 
-			status_t			_ParseCIE(CompilationUnit* unit,
+			status_t			_ParseCIE(ElfSection* debugFrameSection,
+									bool usingEHFrameSection,
+									CompilationUnit* unit,
 									CfaContext& context, off_t cieOffset,
 									CIEAugmentation& cieAugmentation);
 			status_t			_ParseFrameInfoInstructions(
@@ -151,14 +162,13 @@ private:
 			ElfSection*			fDebugRangesSection;
 			ElfSection*			fDebugLineSection;
 			ElfSection*			fDebugFrameSection;
+			ElfSection*			fEHFrameSection;
 			ElfSection*			fDebugLocationSection;
 			ElfSection*			fDebugPublicTypesSection;
 			AbbreviationTableList fAbbreviationTables;
 			DebugInfoEntryFactory fDebugInfoFactory;
 			CompilationUnitList	fCompilationUnits;
 			CompilationUnit*	fCurrentCompilationUnit;
-			bool				fUsingEHFrameSection;
-			bool				fGCC4EHFrameSection;
 			bool				fFinished;
 			status_t			fFinishError;
 };