Enum symbolic_debuginfo::pe::UnwindOperation

pub enum UnwindOperation {
    PushNonVolatile(Register),
    Alloc(u32),
    SetFPRegister,
    SaveNonVolatile(Register, StackFrameOffset),
    SaveXMM(Register, StackFrameOffset),
    Epilog,
    SaveXMM128(Register, StackFrameOffset),
    PushMachineFrame(bool),
    Noop,
}

An unwind operation corresponding to code in the function prolog.

Unwind operations can be used to reverse the effects of the function prolog and restore register values of parent stack frames that have been saved to the stack.

Variants

PushNonVolatile(Register)

Push a nonvolatile integer register, decrementing RSP by 8.

Alloc(u32)

Allocate a fixed-size area on the stack.

SetFPRegister

Establish the frame pointer register by setting the register to some offset of the current RSP. The use of an offset permits establishing a frame pointer that points to the middle of the fixed stack allocation, helping code density by allowing more accesses to use short instruction forms.

SaveNonVolatile(Register, StackFrameOffset)

Save a nonvolatile integer register on the stack using a MOV instead of a PUSH. This code is primarily used for shrink-wrapping, where a nonvolatile register is saved to the stack in a position that was previously allocated.

SaveXMM(Register, StackFrameOffset)

Save the lower 64 bits of a nonvolatile XMM register on the stack.

Epilog

Describes the function epilog.

This operation has been introduced with unwind info version 2 and is not implemented yet.

SaveXMM128(Register, StackFrameOffset)

Save all 128 bits of a nonvolatile XMM register on the stack.

PushMachineFrame(bool)

Push a machine frame. This is used to record the effect of a hardware interrupt or exception. Depending on the error flag, this frame has two different layouts.

This unwind code always appears in a dummy prolog, which is never actually executed but instead appears before the real entry point of an interrupt routine, and exists only to provide a place to simulate the push of a machine frame. This operation records that simulation, which indicates the machine has conceptually done this:

1. Pop RIP return address from top of stack into temp
2. $ss, Push old $rsp, $rflags, $cs, temp
3. If error flag is true, push the error code

Without an error code, RSP was incremented by 40 and the following was frame pushed:

Offset	Value
RSP + 32	$ss
RSP + 24	old $rsp
RSP + 16	$rflags
RSP + 8	$cs
RSP + 0	$rip

With an error code, RSP was incremented by 48 and the following was frame pushed:

Offset	Value
RSP + 40	$ss
RSP + 32	old $rsp
RSP + 24	$rflags
RSP + 16	$cs
RSP + 8	$rip
RSP + 0	error code

Noop

A reserved operation without effect.

Trait Implementations

impl Debug for UnwindOperation

fn fmt(&self, f: &mut Formatter) -> Result<(), Error>

Formats the value using the given formatter.

impl Eq for UnwindOperation

impl Clone for UnwindOperation

fn clone(&self) -> UnwindOperation

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for UnwindOperation

impl PartialEq<UnwindOperation> for UnwindOperation

fn eq(&self, other: &UnwindOperation) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &UnwindOperation) -> bool

This method tests for !=.