Class StackWalkerUtils

java.lang.Object

com.ibm.j9ddr.vm29.j9.stackwalker.StackWalkerUtils

public class StackWalkerUtils
extends Object

Utility methods shared between stack walkers.

Field Summary

Fields

Modifier and Type	Field	Description
static final boolean	DEBUG_LOCALMAP
static final boolean	DEBUG_STACKMAP
static final int	INITIAL_O_SLOTS_CORRUPTION_THRESHOLD	Number of CorruptDataExceptions from iterate-o-slots logic that we report before disabling the o-slots walk
static final Logger	logger	Stack walker logger, can be enabled for debugging stack walker issues when running inside other tools, for example Memory Analyzer.

Constructor Summary

Constructors

Constructor	Description
StackWalkerUtils()

Method Summary

Modifier and Type	Method	Description
static void	disableVerboseLogging()
static void	enableVerboseLogging(int level)	Enables stackwalk verbose logging through j.u.logging - similar in appearance to -verbose:stackwalk output from native.
static void	enableVerboseLogging(int level, PrintStream os)
static void	handleOSlotsCorruption(WalkState walkState, String className, String methodName, CorruptDataException ex)	Since walking OSlots touches a lot more code than just doing a frame walk, we have a layer of corruption handling just above the o-slots logic.
static UDATA	JIT_RESOLVE_PARM(WalkState walkState, int parmNumber)
static boolean	oSlotsCorruptionThresholdReached()
static void	resetOSlotsCorruptionThreshold()
static void	swPrintf(WalkState walkState, int level, String message, Object... args)	This function is a little overloaded.
static void	swPrintMethod(WalkState walkState)
static void	swPrintMethod(WalkState walkState, com.ibm.j9ddr.vm29.pointer.generated.J9MethodPointer method)
static void	WALK_I_SLOT(WalkState walkState, PointerPointer slot)
static void	WALK_INDIRECT_I_SLOT(WalkState walkState, PointerPointer slot, VoidPointer ind)
static void	WALK_INDIRECT_O_SLOT(WalkState walkState, PointerPointer slot, VoidPointer ind)
static void	WALK_METHOD_CLASS(WalkState walkState)
static void	WALK_NAMED_I_SLOT(WalkState walkState, PointerPointer slot, String tag)
static void	WALK_NAMED_INDIRECT_I_SLOT(WalkState walkState, PointerPointer intSlot, VoidPointer indirectSlot, String tag)
static void	WALK_NAMED_INDIRECT_O_SLOT(WalkState walkState, PointerPointer objectSlot, VoidPointer indirectSlot, String tag)
static void	WALK_NAMED_O_SLOT(WalkState walkState, PointerPointer slot, String tag)
static void	WALK_O_SLOT(WalkState walkState, PointerPointer slot)

Methods declared in class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

logger

public static final Logger logger

Stack walker logger, can be enabled for debugging stack walker issues when running inside other tools, for example Memory Analyzer.

INITIAL_O_SLOTS_CORRUPTION_THRESHOLD

public static final int INITIAL_O_SLOTS_CORRUPTION_THRESHOLD

Number of CorruptDataExceptions from iterate-o-slots logic that we report before disabling the o-slots walk

See Also:

• Constant Field Values

DEBUG_STACKMAP

public static final boolean DEBUG_STACKMAP

See Also:

• Constant Field Values

DEBUG_LOCALMAP

public static final boolean DEBUG_LOCALMAP

See Also:

• Constant Field Values

Constructor Details

StackWalkerUtils

public StackWalkerUtils()

Method Details

swPrintf

public static void swPrintf(WalkState walkState,
 int level,
 String message,
 Object... args)

This function is a little overloaded. As well as determining if a message should be printed out for the message level chosen by the tool running the stack walker we also allow for someone turning on logging for debug to get details about the stack walker while running (for example) Memory Analyzer.

Parameters:

walkState -

level -

message -

args -

swPrintMethod

public static void swPrintMethod(WalkState walkState)
                          throws CorruptDataException

Throws:

CorruptDataException

swPrintMethod

public static void swPrintMethod(WalkState walkState,
 com.ibm.j9ddr.vm29.pointer.generated.J9MethodPointer method)
                          throws CorruptDataException

Throws:

CorruptDataException

WALK_METHOD_CLASS

public static void WALK_METHOD_CLASS(WalkState walkState)
                              throws CorruptDataException

Throws:

CorruptDataException

WALK_NAMED_INDIRECT_O_SLOT

public static void WALK_NAMED_INDIRECT_O_SLOT(WalkState walkState,
 PointerPointer objectSlot,
 VoidPointer indirectSlot,
 String tag)
                                       throws CorruptDataException

Throws:

CorruptDataException

WALK_NAMED_INDIRECT_I_SLOT

public static void WALK_NAMED_INDIRECT_I_SLOT(WalkState walkState,
 PointerPointer intSlot,
 VoidPointer indirectSlot,
 String tag)
                                       throws CorruptDataException

Throws:

CorruptDataException

WALK_INDIRECT_O_SLOT

public static void WALK_INDIRECT_O_SLOT(WalkState walkState,
 PointerPointer slot,
 VoidPointer ind)
                                 throws CorruptDataException

Throws:

CorruptDataException

WALK_INDIRECT_I_SLOT

public static void WALK_INDIRECT_I_SLOT(WalkState walkState,
 PointerPointer slot,
 VoidPointer ind)
                                 throws CorruptDataException

Throws:

CorruptDataException

WALK_NAMED_O_SLOT

public static void WALK_NAMED_O_SLOT(WalkState walkState,
 PointerPointer slot,
 String tag)
                              throws CorruptDataException

Throws:

CorruptDataException

WALK_NAMED_I_SLOT

public static void WALK_NAMED_I_SLOT(WalkState walkState,
 PointerPointer slot,
 String tag)
                              throws CorruptDataException

Throws:

CorruptDataException

WALK_O_SLOT

public static void WALK_O_SLOT(WalkState walkState,
 PointerPointer slot)
                        throws CorruptDataException

Throws:

CorruptDataException

WALK_I_SLOT

public static void WALK_I_SLOT(WalkState walkState,
 PointerPointer slot)
                        throws CorruptDataException

Throws:

CorruptDataException

JIT_RESOLVE_PARM

public static UDATA JIT_RESOLVE_PARM(WalkState walkState,
 int parmNumber)
                              throws CorruptDataException

Throws:

CorruptDataException

resetOSlotsCorruptionThreshold

public static void resetOSlotsCorruptionThreshold()

oSlotsCorruptionThresholdReached

public static boolean oSlotsCorruptionThresholdReached()

handleOSlotsCorruption

public static void handleOSlotsCorruption(WalkState walkState,
 String className,
 String methodName,
 CorruptDataException ex)

Since walking OSlots touches a lot more code than just doing a frame walk, we have a layer of corruption handling just above the o-slots logic. We have oslotsCorruptionThreshold attempts, then give up. This method is called in the catch block just below the top-level if (J9_STACKWALK_ITERATE_O_SLOTS) {} conditional.

enableVerboseLogging

public static void enableVerboseLogging(int level)

Enables stackwalk verbose logging through j.u.logging - similar in appearance to -verbose:stackwalk output from native.

enableVerboseLogging

public static void enableVerboseLogging(int level,
 PrintStream os)

disableVerboseLogging

public static void disableVerboseLogging()