Debugger: Call frame unwind optimizations.

- Pass address size to DwarfManager, and subsequently DwarfFile's Load()
  method, as that information is needed in order to parse the frame
  information correctly early on.
- When initially loading debug information, also do a quick pass through
  .{debug,eh}_frame, and build a lookup table of offsets. This is then
  used later when actual unwinding is requested in order to quickly find
  the corresponding FDE/CIE. Should noticeably improve performance when
  stepping through code, especially for larger/more complex executable images.

Implements #8613.

src/apps/debugger/debug_info/DwarfTeamDebugInfo.cpp

@@ -10,6 +10,7 @@
 
 #include <string.h>
 
+#include "arch/Architecture.h"
 #include "DebuggerInterface.h"
 #include "DwarfFile.h"
 #include "DwarfImageDebugInfo.h"
@@ -47,7 +48,7 @@ DwarfTeamDebugInfo::~DwarfTeamDebugInfo()
 status_t
 DwarfTeamDebugInfo::Init()
 {
-	fManager = new(std::nothrow) DwarfManager;
+	fManager = new(std::nothrow) DwarfManager(fArchitecture->AddressSize());
 	if (fManager == NULL)
 		return B_NO_MEMORY;
 

src/apps/debugger/dwarf/DwarfFile.cpp

@@ -442,6 +442,45 @@ private:
 };
 
 
+// #pragma mark - FDELookupInfo
+
+
+struct DwarfFile::FDELookupInfo {
+public:
+	FDELookupInfo(target_addr_t start, target_addr_t end,
+		uint64 fdeOffset, uint64 cieOffset, bool ehFrame)
+	:
+	start(start),
+	end(end),
+	fdeOffset(fdeOffset),
+	cieOffset(cieOffset),
+	ehFrame(ehFrame)
+	{
+	}
+
+	static int CompareFDEInfos(const FDELookupInfo* a, const FDELookupInfo* b)
+	{
+		if (a->start < b->start)
+			return -1;
+		else if (a->start > b->start)
+			return 1;
+
+		return 0;
+	}
+
+	inline bool ContainsAddress(target_addr_t address) const
+	{
+		return address >= start && address < end;
+	}
+
+	target_addr_t 		start;
+	target_addr_t 		end;
+	uint64				fdeOffset;
+	uint64				cieOffset;
+	bool				ehFrame;
+};
+
+
 // #pragma mark - DwarfFile
 
 
@@ -462,8 +501,12 @@ DwarfFile::DwarfFile()
 	fDebugPublicTypesSection(NULL),
 	fDebugTypesSection(NULL),
 	fCompilationUnits(20, true),
+	fTypeUnits(),
+	fDebugFrameInfos(100, true),
+	fEHFrameInfos(100, true),
 	fTypesSectionRequired(false),
 	fFinished(false),
+	fItaniumEHFrameFormat(false),
 	fFinishError(B_OK)
 {
 }
@@ -528,7 +571,7 @@ DwarfFile::StartLoading(const char* fileName, BString& _requiredExternalFile)
 
 
 status_t
-DwarfFile::Load(const BString& externalInfoFilePath)
+DwarfFile::Load(uint8 addressSize, const BString& externalInfoFilePath)
 {
 	status_t error = B_OK;
 	if (fDebugInfoSection == NULL) {
@@ -547,11 +590,27 @@ DwarfFile::Load(const BString& externalInfoFilePath)
 	fDebugRangesSection = debugInfoFile->GetSection(".debug_ranges");
 	fDebugLineSection = debugInfoFile->GetSection(".debug_line");
 	fDebugFrameSection = debugInfoFile->GetSection(".debug_frame");
+
+	if (fDebugFrameSection != NULL) {
+		error = _ParseFrameSection(fDebugFrameSection, addressSize, false,
+			fDebugFrameInfos);
+		if (error != B_OK)
+			return error;
+	}
+
 	// .eh_frame doesn't appear to get copied into separate debug
 	// info files properly, therefore always use it off the main
 	// executable image
 	if (fEHFrameSection == NULL)
 		fEHFrameSection = fElfFile->GetSection(".eh_frame");
+
+	if (fEHFrameSection != NULL) {
+		error = _ParseFrameSection(fEHFrameSection, addressSize, true,
+			fEHFrameInfos);
+		if (error != B_OK)
+			return error;
+	}
+
 	fDebugLocationSection = debugInfoFile->GetSection(".debug_loc");
 	fDebugPublicTypesSection = debugInfoFile->GetSection(".debug_pubtypes");
 
@@ -699,22 +758,12 @@ DwarfFile::UnwindCallFrame(CompilationUnit* unit, uint8 addressSize,
 	const DwarfTargetInterface* inputInterface,
 	DwarfTargetInterface* outputInterface, target_addr_t& _framePointer)
 {
-	status_t result = B_ENTRY_NOT_FOUND;
+	FDELookupInfo* info = _GetContainingFDEInfo(location);
+	if (info == NULL)
+		return B_ENTRY_NOT_FOUND;
 
-	// first try to find the FDE in .debug_frame
+	return _UnwindCallFrame(unit, addressSize, subprogramEntry, location, info,
-	if (fDebugFrameSection != NULL) {
+		inputInterface, outputInterface, _framePointer);
-		result = _UnwindCallFrame(false, unit, addressSize, subprogramEntry,
-			location, inputInterface, outputInterface, _framePointer);
-	}
-
-	// if .debug_frame isn't present, or if the FDE wasn't found there,
-	// try .eh_frame
-	if (result == B_ENTRY_NOT_FOUND && fEHFrameSection != NULL) {
-		result = _UnwindCallFrame(true, unit, addressSize, subprogramEntry,
-			location, inputInterface, outputInterface, _framePointer);
-	}
-
-	return result;
 }
 
 
@@ -1080,6 +1129,116 @@ DwarfFile::_ParseTypesSection()
 }
 
 
+status_t
+DwarfFile::_ParseFrameSection(ElfSection* section, uint8 addressSize,
+	bool ehFrame, FDEInfoList& infos)
+{
+	if (ehFrame) {
+		fItaniumEHFrameFormat = section->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.
+	}
+
+	DataReader dataReader((uint8*)section->Data(),
+		section->Size(), addressSize);
+
+	while (dataReader.BytesRemaining() > 0) {
+		// length
+		bool dwarf64;
+		off_t entryOffset = dataReader.Offset();
+		uint64 length = dataReader.ReadInitialLength(dwarf64);
+
+		TRACE_CFI("DwarfFile::_ParseFrameSection(): offset: %" B_PRIdOFF
+			", length: %" B_PRId64 "\n", entryOffset, length);
+
+		if (length > (uint64)dataReader.BytesRemaining())
+			return B_BAD_DATA;
+		off_t lengthOffset = dataReader.Offset();
+
+		// CIE ID/CIE pointer
+		uint64 cieID = dwarf64
+			? dataReader.Read<uint64>(0) : dataReader.Read<uint32>(0);
+
+		// In .debug_frame ~0 indicates a CIE, in .eh_frame 0 does.
+		if (ehFrame
+			? cieID == 0
+			: (dwarf64
+				? cieID == 0xffffffffffffffffULL
+				: cieID == 0xffffffff)) {
+			// this is a CIE -- skip it
+		} else {
+			// this is a FDE
+			uint64 initialLocationOffset = dataReader.Offset();
+			// In .eh_frame the CIE offset is a relative back offset.
+			if (ehFrame) {
+				if (cieID > (uint64)lengthOffset) {
+					TRACE_CFI("Invalid CIE offset: %" B_PRIu64 ", max "
+						"possible: %" B_PRIu64 "\n", cieID, lengthOffset);
+					break;
+				}
+				// convert to a section relative offset
+				cieID = lengthOffset - cieID;
+			}
+
+
+			CfaContext context;
+			CIEAugmentation cieAugmentation;
+			// when using .eh_frame format, we need to parse the CIE's
+			// augmentation up front in order to know how the FDE's addresses
+			//  will be represented
+			DataReader cieReader;
+			off_t cieRemaining;
+			status_t error = _ParseCIEHeader(section, ehFrame, NULL,
+				addressSize, context, cieID, cieAugmentation, cieReader,
+				cieRemaining);
+			if (error != B_OK)
+				return error;
+			if (cieReader.HasOverflow())
+				return B_BAD_DATA;
+			if (cieRemaining < 0)
+				return B_BAD_DATA;
+
+			target_addr_t initialLocation = cieAugmentation.ReadEncodedAddress(
+				dataReader, fElfFile, section);
+			target_addr_t addressRange = cieAugmentation.ReadEncodedAddress(
+				dataReader, fElfFile, section, true);
+
+			if (dataReader.HasOverflow())
+				return B_BAD_DATA;
+
+			if ((cieAugmentation.FDEAddressType()
+					& CFI_ADDRESS_TYPE_PC_RELATIVE) != 0) {
+				initialLocation += initialLocationOffset;
+			}
+
+			// for unknown reasons, the debug frame sections generated by gcc
+			// sometimes contain duplicates at different offsets within the
+			// section. In such a case, simply skip the duplicates.
+			FDELookupInfo* temp = _GetContainingFDEInfo(initialLocation,
+				infos);
+			if (temp == NULL) {
+				FDELookupInfo* info = new(std::nothrow)FDELookupInfo(
+					initialLocation, initialLocation + addressRange - 1,
+					entryOffset, cieID, ehFrame);
+				if (info == NULL)
+					return B_NO_MEMORY;
+
+				ObjectDeleter<FDELookupInfo> infoDeleter(info);
+				if (!infos.BinaryInsert(info, FDELookupInfo::CompareFDEInfos))
+					return B_NO_MEMORY;
+
+				infoDeleter.Detach();
+			}
+		}
+
+		dataReader.SeekAbsolute(lengthOffset + length);
+	}
+
+	return B_OK;
+}
+
+
 status_t
 DwarfFile::_ParseCompilationUnit(CompilationUnit* unit)
 {
@@ -1705,69 +1864,24 @@ DwarfFile::_ParseLineInfo(CompilationUnit* unit)
 
 
 status_t
-DwarfFile::_UnwindCallFrame(bool usingEHFrameSection, CompilationUnit* unit,
+DwarfFile::_UnwindCallFrame(CompilationUnit* unit, uint8 addressSize,
-	uint8 addressSize, DIESubprogram* subprogramEntry, target_addr_t location,
+	DIESubprogram* subprogramEntry, target_addr_t location,
-	const DwarfTargetInterface* inputInterface,
+	const FDELookupInfo* info, const DwarfTargetInterface* inputInterface,
 	DwarfTargetInterface* outputInterface, target_addr_t& _framePointer)
 {
-	ElfSection* currentFrameSection = (usingEHFrameSection)
+	ElfSection* currentFrameSection = (info->ehFrame)
 		? 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(%#" B_PRIx64 ")\n", location);
 
 	DataReader dataReader((uint8*)currentFrameSection->Data(),
 		currentFrameSection->Size(), unit != NULL
 			? unit->AddressSize() : addressSize);
+	dataReader.SeekAbsolute(info->fdeOffset);
 
-	while (dataReader.BytesRemaining() > 0) {
-		// length
 	bool dwarf64;
-		TRACE_CFI_ONLY(off_t entryOffset = dataReader.Offset();)
 	uint64 length = dataReader.ReadInitialLength(dwarf64);
-
+	uint64 lengthOffset = dataReader.Offset();
-		TRACE_CFI("DwarfFile::_UnwindCallFrame(): offset: %" B_PRIdOFF
-			", length: %" B_PRId64 "\n", entryOffset, length);
-
-		if (length > (uint64)dataReader.BytesRemaining())
-			return B_BAD_DATA;
-		off_t lengthOffset = dataReader.Offset();
-
-		// CIE ID/CIE pointer
-		uint64 cieID = dwarf64
-			? dataReader.Read<uint64>(0) : dataReader.Read<uint32>(0);
-
-		// In .debug_frame ~0 indicates a CIE, in .eh_frame 0 does.
-		if (usingEHFrameSection
-			? cieID == 0
-			: (dwarf64
-				? cieID == 0xffffffffffffffffULL
-				: cieID == 0xffffffff)) {
-			// this is a CIE -- skip it
-		} else {
-			// this is a FDE
-			uint64 initialLocationOffset = dataReader.Offset();
-			// In .eh_frame the CIE offset is a relative back offset.
-			if (usingEHFrameSection) {
-				if (cieID > (uint64)lengthOffset) {
-					TRACE_CFI("Invalid CIE offset: %" B_PRIu64 ", max "
-						"possible: %" B_PRIu64 "\n", cieID, lengthOffset);
-					break;
-				}
-				// convert to a section relative offset
-				cieID = lengthOffset - cieID;
-			}
-
 
 	CfaContext context;
 	CIEAugmentation cieAugmentation;
@@ -1777,7 +1891,7 @@ DwarfFile::_UnwindCallFrame(bool usingEHFrameSection, CompilationUnit* unit,
 	DataReader cieReader;
 	off_t cieRemaining;
 	status_t error = _ParseCIEHeader(currentFrameSection,
-				usingEHFrameSection, unit, addressSize, context, cieID,
+		info->ehFrame, unit, addressSize, context, info->cieOffset,
 		cieAugmentation, cieReader, cieRemaining);
 	if (error != B_OK)
 		return error;
@@ -1786,44 +1900,24 @@ DwarfFile::_UnwindCallFrame(bool usingEHFrameSection, CompilationUnit* unit,
 	if (cieRemaining < 0)
 		return B_BAD_DATA;
 
-			target_addr_t initialLocation = cieAugmentation.ReadEncodedAddress(
+	uint64 remaining = lengthOffset + length - info->fdeOffset;
-				dataReader, fElfFile, currentFrameSection);
-			target_addr_t addressRange = cieAugmentation.ReadEncodedAddress(
-				dataReader, fElfFile, currentFrameSection, true);
-
-			if (dataReader.HasOverflow())
-				return B_BAD_DATA;
-
-			if ((cieAugmentation.FDEAddressType()
-					& CFI_ADDRESS_TYPE_PC_RELATIVE) != 0) {
-				initialLocation += initialLocationOffset;
-			}
-
-			// TODO: For GCC 2 .eh_frame sections things work differently: The
-			// initial locations are relocated by the runtime loader and
-			// afterwards point to the absolute addresses. Fortunately the
-			// relocations that always seem to be used are R_386_RELATIVE, so
-			// that the value we read from the file is already absolute
-			// (assuming an unchanged segment load address).
-
-			TRACE_CFI("location: %" B_PRIx64 ", initial location: %" B_PRIx64
-				", address range: %" B_PRIx64 "\n", location, initialLocation,
-				addressRange);
-
-			if (location >= initialLocation
-				&& location < initialLocation + addressRange) {
-				// This is the FDE we're looking for.
-				off_t remaining = lengthOffset + length
-					- dataReader.Offset();
 	if (remaining < 0)
 		return B_BAD_DATA;
 
+	// skip CIE ID, initial offset and range, since we already know those
+	// from FDELookupInfo.
+	dwarf64	? dataReader.Read<uint64>(0) : dataReader.Read<uint32>(0);
+	cieAugmentation.ReadEncodedAddress(dataReader, fElfFile,
+		currentFrameSection);
+	cieAugmentation.ReadEncodedAddress(dataReader, fElfFile,
+		currentFrameSection, true);
+
 	TRACE_CFI("  found fde: length: %" B_PRIu64 " (%" B_PRIdOFF
 		"), CIE offset: %#" B_PRIx64 ", location: %#" B_PRIx64 ", "
-					"range: %#" B_PRIx64 "\n", length, remaining, cieID,
+		"range: %#" B_PRIx64 "\n", length, dataReader.BytesRemaining(),
-					initialLocation, addressRange);
+		info->cieOffset, info->start, info->end - info->start);
 
-				context.SetLocation(location, initialLocation);
+	context.SetLocation(location, info->start);
 	uint32 registerCount = outputInterface->CountRegisters();
 	error = context.Init(registerCount);
 	if (error != B_OK)
@@ -1848,10 +1942,6 @@ DwarfFile::_UnwindCallFrame(bool usingEHFrameSection, CompilationUnit* unit,
 		TRACE_CFI("  failed to read FDE augmentation data!\n");
 		return error;
 	}
-				// adjust remaining byte count to take augmentation bytes
-				// (if any) into account.
-				remaining = lengthOffset + length
-					- dataReader.Offset();
 
 	error = context.SaveInitialRuleSet();
 	if (error != B_OK)
@@ -1996,14 +2086,8 @@ DwarfFile::_UnwindCallFrame(bool usingEHFrameSection, CompilationUnit* unit,
 	}
 
 	_framePointer = frameAddress;
+
 	return B_OK;
-			}
-		}
-
-		dataReader.SeekAbsolute(lengthOffset + length);
-	}
-
-	return B_ENTRY_NOT_FOUND;
 }
 
 
@@ -2842,3 +2926,40 @@ DwarfFile::_GetContainingCompilationUnit(off_t refAddr) const
 	CompilationUnit* unit = fCompilationUnits.ItemAt(lower);
 	return unit->ContainsAbsoluteOffset(refAddr) ? unit : NULL;
 }
+
+
+DwarfFile::FDELookupInfo*
+DwarfFile::_GetContainingFDEInfo(target_addr_t offset) const
+{
+	FDELookupInfo* info = NULL;
+	if (fDebugFrameSection != NULL) {
+		info = _GetContainingFDEInfo(offset, fDebugFrameInfos);
+		if (info != NULL)
+			return info;
+	}
+
+	return _GetContainingFDEInfo(offset, fEHFrameInfos);
+}
+
+
+DwarfFile::FDELookupInfo*
+DwarfFile::_GetContainingFDEInfo(target_addr_t offset,
+	const FDEInfoList& infoList) const
+{
+	// binary search
+	int lower = 0;
+	int upper = infoList.CountItems() - 1;
+	if (upper < 0)
+		return NULL;
+
+	while (lower < upper) {
+		int mid = (lower + upper + 1) / 2;
+		if (offset < infoList.ItemAt(mid)->start)
+			upper = mid - 1;
+		else
+			lower = mid;
+	}
+
+	FDELookupInfo* info = infoList.ItemAt(lower);
+	return info->ContainsAddress(offset) ? info : NULL;
+}

src/apps/debugger/dwarf/DwarfFile.h

@@ -37,7 +37,8 @@ public:
 
 			status_t			StartLoading(const char* fileName,
 									BString& _requiredExternalFile);
-			status_t			Load(const BString& externalFilePath);
+			status_t			Load(uint8 addressSize,
+									const BString& externalFilePath);
 			status_t			FinishLoading();
 
 			const char*			Name() const		{ return fName; }
@@ -108,14 +109,19 @@ private:
 			struct ExpressionEvaluationContext;
 			struct FDEAugmentation;
 			struct CIEAugmentation;
+			struct FDELookupInfo;
 
 			typedef DoublyLinkedList<AbbreviationTable> AbbreviationTableList;
 			typedef BObjectList<CompilationUnit> CompilationUnitList;
 			typedef BOpenHashTable<TypeUnitTableHashDefinition> TypeUnitTable;
+			typedef BObjectList<FDELookupInfo> FDEInfoList;
 
 private:
 			status_t			_ParseDebugInfoSection();
 			status_t			_ParseTypesSection();
+			status_t			_ParseFrameSection(ElfSection* section,
+									uint8 addressSize, bool ehFrame,
+									FDEInfoList& infos);
 			status_t			_ParseCompilationUnit(CompilationUnit* unit);
 			status_t			_ParseTypeUnit(TypeUnit* unit);
 			status_t			_ParseDebugInfoEntry(DataReader& dataReader,
@@ -131,11 +137,11 @@ private:
 
 			status_t			_ParseLineInfo(CompilationUnit* unit);
 
-			status_t			_UnwindCallFrame(bool usingEHFrameSection,
+			status_t			_UnwindCallFrame(CompilationUnit* unit,
-									CompilationUnit* unit,
 									uint8 addressSize,
 									DIESubprogram* subprogramEntry,
 									target_addr_t location,
+									const FDELookupInfo* info,
 									const DwarfTargetInterface* inputInterface,
 									DwarfTargetInterface* outputInterface,
 									target_addr_t& _framePointer);
@@ -185,6 +191,13 @@ private:
 			CompilationUnit*	_GetContainingCompilationUnit(
 									off_t refAddr) const;
 
+			FDELookupInfo*		_GetContainingFDEInfo(
+									target_addr_t offset) const;
+
+			FDELookupInfo*		_GetContainingFDEInfo(
+									target_addr_t offset,
+									const FDEInfoList& infoList) const;
+
 private:
 			friend class 		DwarfFile::ExpressionEvaluationContext;
 
@@ -207,8 +220,11 @@ private:
 			DebugInfoEntryFactory fDebugInfoFactory;
 			CompilationUnitList	fCompilationUnits;
 			TypeUnitTable		fTypeUnits;
+			FDEInfoList			fDebugFrameInfos;
+			FDEInfoList			fEHFrameInfos;
 			bool				fTypesSectionRequired;
 			bool				fFinished;
+			bool				fItaniumEHFrameFormat;
 			status_t			fFinishError;
 };
 

src/apps/debugger/dwarf/DwarfManager.cpp

@@ -15,8 +15,9 @@
 #include "DwarfFileLoadingState.h"
 
 
-DwarfManager::DwarfManager()
+DwarfManager::DwarfManager(uint8 addressSize)
 	:
+	fAddressSize(addressSize),
 	fLock("dwarf manager")
 {
 }
@@ -65,7 +66,7 @@ DwarfManager::LoadFile(const char* fileName, DwarfFileLoadingState& _state)
 		}
 	}
 
-	error = file->Load(_state.locatedExternalInfoPath);
+	error = file->Load(fAddressSize, _state.locatedExternalInfoPath);
 	if (error != B_OK) {
 		_state.state = DWARF_FILE_LOADING_STATE_FAILED;
 		return error;

src/apps/debugger/dwarf/DwarfManager.h

@@ -17,7 +17,7 @@ struct DwarfFileLoadingState;
 
 class DwarfManager {
 public:
-								DwarfManager();
+								DwarfManager(uint8 addressSize);
 								~DwarfManager();
 
 			status_t			Init();
@@ -36,6 +36,7 @@ private:
 			typedef DoublyLinkedList<DwarfFile> FileList;
 
 private:
+			uint8				fAddressSize;
 			BLocker				fLock;
 			FileList			fFiles;
 };