Struct Alias 

pub struct Alias<'a> { /* private fields */ }

The analysis over one function.

It borrows the module because a global’s address is a symbol and whether two symbols are two objects is a question about the module, and it borrows the function because everything else is. The escape analysis is run once when this is built, since every query may ask it and it is one walk over the function.

Implementations

impl<'a> Alias<'a>

pub fn new(func: &'a Func, module: &'a Module) -> Self

The analysis of this function, with the type-based layer on, which is GCC’s -O2.

pub fn with(func: &'a Func, module: &'a Module, options: Options) -> Self

The same, with the type-based layer where the command line left it.

pub const fn escapes(&self) -> &Escapes

Which locals escaped, for a caller that wants the fact on its own.

pub const fn counts(&self) -> &Counts

What each layer has answered so far.

pub fn reads(&self, inst: Inst) -> Option<Access>

The bytes this instruction reads, if it reads any.

pub fn writes(&self, inst: Inst) -> Option<Access>

The bytes this instruction writes, if it writes any.

pub fn query(&mut self, a: &Access, b: &Access) -> Answer

Whether these two references can touch the same byte.

pub fn clobbered_by(&mut self, reference: &Access, call: Inst) -> Answer

Whether this call can write the bytes the reference covers.

GCC’s call_may_clobber_ref_p_1. Without interprocedural summaries the honest answer for anything whose address escaped is yes, and section 8.4 says so plainly: the full mod and ref summary is ipa-modref, it is five and a half thousand lines, and it is document 34’s. What is here is the cheap part of it, which is the attributes a C programmer already wrote and the escape analysis.

pub fn read_by(&mut self, reference: &Access, call: Inst) -> Answer

Whether this call can read them.

GCC’s ref_maybe_used_by_call_p_1, and the same argument as Alias::clobbered_by.

Trait Implementations

impl<'a> Debug for Alias<'a>

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

Formats the value using the given formatter.