org.jikesrvm.ia32

Class StackframeLayoutConstants

java.lang.Object

org.jikesrvm.ia32.StackframeLayoutConstants

public final class StackframeLayoutConstants
extends Object

-----------------------------------------------------------------------
                   Stackframe layout conventions - Intel version.
-----------------------------------------------------------------------
 

A stack is an array of "slots", declared formally as integers, each slot containing either a primitive (byte, int, float, etc), an object pointer, a machine code pointer (a return address pointer), or a pointer to another slot in the same stack (a frame pointer). The interpretation of a slot's contents depends on the current value of IP, the machine instruction address register. Each machine code generator provides maps, for use by the garbage collector, that tell how to interpret the stack slots at "safe points" in the program's execution.

Here's a picture of what a stack might look like in memory.

Note: this (array) object is drawn upside down compared to other objects because the hardware stack grows from high memory to low memory, but array objects are layed out from low memory to high (header first).

  hi-memory
              +---------------+                                            ...
              |     IP=0      |                                             .
              +---------------+                                             .
          +-> |     FP=0      |   <-- "end of vm stack" sentinel            .
          |   +---------------+                                             . caller's frame
          |   |    cmid=0      |   <-- "invisible method" id                .
          |   +---------------+                                          ---.
          |   |   parameter0  |  \                                        | .
          |   +---------------+   \ parameter area                        | .
          |   |   parameter1  |   /  (== caller's operand stack area)     | .
   ---    |   +---------------+  /                                        |...
    |     |   |   saved IP    |  <-- return address (in caller)           |
    |      \  +---------------+                                           |
  header FP-> |   saved FP    |  <-- this frame's caller's frame          |
    |         +---------------+                                           |
    |         |    cmid       |  <-- this frame's compiledmethod id       |
    |         +---------------+                                           |
    |         |   saved GPRs  |  \                                        |
    |         +---------------+   \ nonvolatile register save area        |
    |         |   saved FPRS  |   /                                       | frame
    |         +---------------+                                           |
    |         |   local0      |  \                                        |
   body       +---------------+   \_local variables area                  |
    |         |   local1      |   /                                       |
    |         +---------------+  /                                        |
    |         |   operand0    |  \                                        |
    |         +---------------+   \_operand stack area                    |
    |    SP-> |   operand1    |   /                                       |
    |         +---------------+  /                                        |
    |         |     ...       |                                           |
   ---        +===============+                                          ---
              |     ...       |
              +---------------+
 stackLimit-> |     ...       | \
              +---------------+  \_guard region for detecting & processing stack overflow
              |     ...       |  /
              +---------------+ /
              |(object header)|
  low-memory  +---------------+
 

The opt compiler uses a different stackframe layout

  hi-memory
              +---------------+                                            ...
              |     IP=0      |                                             .
              +---------------+                                             .
          +-> |     FP=0      |   <-- "end of vm stack" sentinel           .
          |   +---------------+                                             . caller's frame
          |   |    cmid=-1    |   <-- "invisible method" id                .
          |   +---------------+                                          ---.
          |   |   parameter0  |  \                                        | .
          |   +---------------+   \ parameter area                        | .
          |   |   parameter1  |   /  (== caller's operand stack area)     | .
   ---    |   +---------------+  /                                        |...
    |     |   |   saved IP    |  <-- return address (in caller)           |
    |      \  +---------------+                                           |
  header FP-> |   saved FP    |  <-- this frame's caller's frame          |
    |         +---------------+                                           |
    |         |    cmid       |  <-- this frame's compiledmethod id       |
   ---        +---------------+                                           |
    |         |               |                                           |
    |         |  Spill Area   |  <-- spills and other method-specific     |
    |         |     ...       |      compiler-managed storage             |
    |         +---------------+                                           |
    |         |   Saved FP    |     only SaveVolatile Frames              |
    |         |    State      |                                           |
    |         +---------------+                                           |
    |         |  VolGPR[0]    |                                           |
    |         |     ...       |     only SaveVolatile Frames              |
    |         |  VolGPR[n]    |                                           |
    |         +---------------+                                           |
   body       |  NVolGPR[k]   |  <-- info.getUnsignedNonVolatileOffset()  | frame
    |         |     ...       |   k == info.getFirstNonVolatileGPR()      |
    |         |  NVolGPR[n]   |                                           |
    |         +---------------+                                           |
    |         |  NVolFPR[k]   |                                           |
    |         |     ...       |   k == info.getFirstNonVolatileFPR()      |
    |         |  NVolFPR[n]   |                                           |
    |         +---------------+                                           |
    |         |   parameter0  |  \                                        |
    |         +---------------+   \_parameters to callee frame            |
    |    SP-> |   parameter1  |   /                                       |
    |         +---------------+  /                                        |
    |         |     ...       |                                           |
   ---        +===============+                                          ---
              |     ...       |
              +---------------+
 stackLimit-> |     ...       | \
              +---------------+  \_guard region for detecting & processing stack overflow
              |     ...       |  /
              +---------------+ /
              |(object header)|
  low-memory  +---------------+

 

Field Summary

Fields

Modifier and Type	Field and Description
static int	BYTES_IN_STACKSLOT
static int	FPU_STATE_SIZE space to save entire FPU state.
static int	INVISIBLE_METHOD_ID marker for "assembler" frames that have no associated RVMMethod
static int	LOG_BYTES_IN_STACKSLOT
static int	STACK_SIZE_BOOT total stack space to allocate for boot thread (includes guard region)
static int	STACK_SIZE_COLLECTOR total stack space to allocate for collector thread (includes guard region)
static int	STACK_SIZE_DLOPEN max space needed for dlopen sys call
static int	STACK_SIZE_GCDISABLED max space needed while running with gc disabled
static int	STACK_SIZE_GROW how much to grow stack when overflow detected
static int	STACK_SIZE_GUARD max space needed for stack overflow trap processing
static int	STACK_SIZE_JNINATIVE_GROW
static int	STACK_SIZE_MAX upper limit on stack size (includes guard region)
static int	STACK_SIZE_NORMAL initial stack space to allocate for normal thread (includes guard region)
static int	STACK_SIZE_SYSCALL max space needed for any native code called by vm
static int	STACKFRAME_ALIGNMENT
static Offset	STACKFRAME_BODY_OFFSET offset of work area from FP
static Offset	STACKFRAME_FRAME_POINTER_OFFSET base of this frame
static int	STACKFRAME_HEADER_SIZE size of frame header, in bytes
static Offset	STACKFRAME_METHOD_ID_OFFSET offset of method id from FP
static Offset	STACKFRAME_RETURN_ADDRESS_OFFSET offset of caller's return address from FP
static Address	STACKFRAME_SENTINEL_FP fp value indicating end of stack walkback
static int	XMM_STATE_SIZE Currently only use the low 8 bytes, only use 4 SSE2 params

Constructor Summary

Constructors

Modifier	Constructor and Description
private	StackframeLayoutConstants()

Method Summary

Methods inherited from class java.lang.Object

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

Field Detail

LOG_BYTES_IN_STACKSLOT

public static final int LOG_BYTES_IN_STACKSLOT

See Also:

Constant Field Values

BYTES_IN_STACKSLOT

public static final int BYTES_IN_STACKSLOT

See Also:

Constant Field Values

STACKFRAME_RETURN_ADDRESS_OFFSET

public static final Offset STACKFRAME_RETURN_ADDRESS_OFFSET

offset of caller's return address from FP

STACKFRAME_FRAME_POINTER_OFFSET

public static final Offset STACKFRAME_FRAME_POINTER_OFFSET

base of this frame

STACKFRAME_METHOD_ID_OFFSET

public static final Offset STACKFRAME_METHOD_ID_OFFSET

offset of method id from FP

STACKFRAME_BODY_OFFSET

public static final Offset STACKFRAME_BODY_OFFSET

offset of work area from FP

STACKFRAME_HEADER_SIZE

public static final int STACKFRAME_HEADER_SIZE

size of frame header, in bytes

See Also:

Constant Field Values

FPU_STATE_SIZE

public static final int FPU_STATE_SIZE

space to save entire FPU state. The FPU state is saved only for 'bridge' frames

See Also:

Constant Field Values

XMM_STATE_SIZE

public static final int XMM_STATE_SIZE

Currently only use the low 8 bytes, only use 4 SSE2 params

See Also:

Constant Field Values

STACKFRAME_SENTINEL_FP

public static final Address STACKFRAME_SENTINEL_FP

fp value indicating end of stack walkback

INVISIBLE_METHOD_ID

public static final int INVISIBLE_METHOD_ID

marker for "assembler" frames that have no associated RVMMethod

See Also:

Constant Field Values

STACKFRAME_ALIGNMENT

public static final int STACKFRAME_ALIGNMENT

See Also:

Constant Field Values

STACK_SIZE_GROW

public static final int STACK_SIZE_GROW

how much to grow stack when overflow detected

See Also:

Constant Field Values

STACK_SIZE_GUARD

public static final int STACK_SIZE_GUARD

max space needed for stack overflow trap processing

See Also:

Constant Field Values

STACK_SIZE_SYSCALL

public static final int STACK_SIZE_SYSCALL

max space needed for any native code called by vm

See Also:

Constant Field Values

STACK_SIZE_DLOPEN

public static final int STACK_SIZE_DLOPEN

max space needed for dlopen sys call

See Also:

Constant Field Values

STACK_SIZE_GCDISABLED

public static final int STACK_SIZE_GCDISABLED

max space needed while running with gc disabled

See Also:

Constant Field Values

STACK_SIZE_NORMAL

public static final int STACK_SIZE_NORMAL

initial stack space to allocate for normal thread (includes guard region)

See Also:

Constant Field Values

STACK_SIZE_BOOT

public static final int STACK_SIZE_BOOT

total stack space to allocate for boot thread (includes guard region)

See Also:

Constant Field Values

STACK_SIZE_COLLECTOR

public static final int STACK_SIZE_COLLECTOR

total stack space to allocate for collector thread (includes guard region)

See Also:

Constant Field Values

STACK_SIZE_MAX

public static final int STACK_SIZE_MAX

upper limit on stack size (includes guard region)

See Also:

Constant Field Values

STACK_SIZE_JNINATIVE_GROW

public static final int STACK_SIZE_JNINATIVE_GROW

See Also:

Constant Field Values

Constructor Detail

StackframeLayoutConstants

private StackframeLayoutConstants()