Enum CallgraphStrategy

pub enum CallgraphStrategy {
    None,
    Dwarf,
    LastBranchRecord,
    ShadowCallStack,
    FramePointer,
    // some variants omitted
}

Various approaches to obtaining a backtrace

Variants

None

Don’t try to get a callgraph

Dwarf

Copy out stack memory and attempt to parse the DWARF info. This is the slowest and most memory intensive of the approaches, but gives the most accurate callgraphs. Parsing dwarf allows the callgraph to trace inlined and leaf functions which other approaches do not support.

LastBranchRecord

Intel CPUs support a hardware feature called Last Branch Records (LBR)s which record up to the last 32 calls made depending on hardware version. On supported CPUs, this is a low overhead approach to finding the callgraph with the caveat that stacks that exceed 32 calls in depth will overflow the hardware buffer.

ShadowCallStack

arm and riscv support shadow call stacks which are an efficient way for us to find and copy out the call stack. However, leaf functions and code compiled without shadow callstack support, such as the vdso will not appear in the returned callgraph.

FramePointer

A general approach of parsing the frame pointers of the callstack. Frame pointers are supported across architectures and are slightly more expensive than the lbrs or shadow call stacks, but much cheaper than parsing dwarf. Code compiled with omitted frame pointers and inlined functions will not appear in the resulting stacks.

Implementations

impl CallgraphStrategy

pub fn from_primitive(prim: u8) -> Option<Self>

pub fn from_primitive_allow_unknown(prim: u8) -> Self

pub fn unknown() -> Self

pub const fn into_primitive(self) -> u8

pub fn is_unknown(&self) -> bool

Trait Implementations

impl Clone for CallgraphStrategy

fn clone(&self) -> CallgraphStrategy

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for CallgraphStrategy

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

Formats the value using the given formatter.

impl<D: ResourceDialect> Decode<CallgraphStrategy, D> for CallgraphStrategy

fn new_empty() -> Self

Creates a valid instance of Self. The specific value does not matter, since it will be overwritten by decode.

unsafe fn decode( &mut self, decoder: &mut Decoder<'_, D>, offset: usize, _depth: Depth, ) -> Result<()>

Decodes an object of type T from the decoder’s buffers into self.

impl<D: ResourceDialect> Encode<CallgraphStrategy, D> for CallgraphStrategy

unsafe fn encode( self, encoder: &mut Encoder<'_, D>, offset: usize, _depth: Depth, ) -> Result<()>

Encodes the object into the encoder’s buffers. Any handles stored in the object are swapped for Handle::INVALID.

impl Hash for CallgraphStrategy

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for CallgraphStrategy

fn cmp(&self, other: &CallgraphStrategy) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for CallgraphStrategy

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for CallgraphStrategy

fn partial_cmp(&self, other: &CallgraphStrategy) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl TypeMarker for CallgraphStrategy

type Owned = CallgraphStrategy

The owned Rust type which this FIDL type decodes into.

fn inline_align(_context: Context) -> usize

Returns the minimum required alignment of the inline portion of the encoded object. It must be a (nonzero) power of two.

fn inline_size(_context: Context) -> usize

Returns the size of the inline portion of the encoded object, including padding for alignment. Must be a multiple of inline_align.

fn encode_is_copy() -> bool

Returns true if the memory layout of Self::Owned matches the FIDL wire format and encoding requires no validation. When true, we can optimize encoding arrays and vectors of Self::Owned to a single memcpy.

fn decode_is_copy() -> bool

Returns true if the memory layout of Self::Owned matches the FIDL wire format and decoding requires no validation. When true, we can optimize decoding arrays and vectors of Self::Owned to a single memcpy.

impl ValueTypeMarker for CallgraphStrategy

type Borrowed<'a> = CallgraphStrategy

The Rust type to use for encoding. This is a particular Encode<Self> type cheaply obtainable from &Self::Owned. There are three cases:

fn borrow(value: &<Self as TypeMarker>::Owned) -> Self::Borrowed<'_>

Cheaply converts from &Self::Owned to Self::Borrowed.

impl Copy for CallgraphStrategy

impl Eq for CallgraphStrategy

impl StructuralPartialEq for CallgraphStrategy