Module rustc_mir::transform

Modules

add_call_guards
add_moves_for_packed_drops
add_retag	This pass adds validation calls (AcquireValid, ReleaseValid) where appropriate. It has to be run really early, before transformations like inlining, because introducing these calls adds UB – so, conceptually, this pass is actually part of MIR building, and only after this pass we think of the program has having the normal MIR semantics.
check_const_item_mutation
check_consts	Check the bodies of consts, statics and const fns for illegal operations.
check_packed_ref
check_unsafety
cleanup_post_borrowck	This module provides a pass to replacing the following statements with Nops
const_debuginfo	Finds locals which are assigned once to a const and unused except for debuginfo and converts their debuginfo to use the const directly, allowing the local to be removed.
const_goto	This pass optimizes the following sequence
const_prop	Propagates constants for early reporting of statically known assertion failures
coverage
deaggregator
deduplicate_blocks	This pass finds basic blocks that are completely equal, and replaces all uses with just one of them.
dest_prop	Propagates assignment destinations backwards in the CFG to eliminate redundant assignments.
dump_mir	This pass just dumps MIR at a specified point.
early_otherwise_branch
elaborate_drops
function_item_references
generator	This is the implementation of the pass which transforms generators into state machines.
inline	Inlining pass for MIR functions
instcombine	Performs various peephole optimizations.
lower_intrinsics	Lowers intrinsic calls
match_branches
multiple_return_terminators	This pass removes jumps to basic blocks containing only a return, and replaces them with a return instead.
no_landing_pads	This pass removes the unwind branch of all the terminators when the no-landing-pads option is specified.
nrvo	See the docs for RenameReturnPlace.
promote_consts	A pass that promotes borrows of constant rvalues.
remove_noop_landing_pads
remove_storage_markers	This pass removes storage markers if they won’t be emitted during codegen.
remove_unneeded_drops	This pass replaces a drop of a type that does not need dropping, with a goto
required_consts
rustc_peek
simplify	A number of passes which remove various redundancies in the CFG.
simplify_branches	A pass that simplifies branches when their condition is known.
simplify_comparison_integral
simplify_try	The general point of the optimizations provided here is to simplify something like:
uninhabited_enum_branching	A pass that eliminates branches on uninhabited enum variants.
unreachable_prop	A pass that propagates the unreachable terminator of a block to its predecessors when all of their successors are unreachable. This is achieved through a post-order traversal of the blocks.
validate	Validates the MIR to ensure that invariants are upheld.

Structs

MirSource

Where a specific mir::Body comes from.

Traits

MirPass

A streamlined trait that you can implement to create a pass; the pass will be named after the type, and it will consist of a main loop that goes over each available MIR and applies run_pass.

Functions

default_name	Generates a default name for the pass based on the name of the type T.
inner_mir_for_ctfe
inner_optimized_mir
is_mir_available
mir_const	Make MIR ready for const evaluation. This is run on all MIR, not just on consts!
mir_const_qualif
mir_drops_elaborated_and_const_checked	Obtain just the main MIR (no promoteds) and run some cleanups on it. This also runs mir borrowck before doing so in order to ensure that borrowck can be run and doesn’t end up missing the source MIR due to stealing happening.
mir_for_ctfe	Compute the MIR that is used during CTFE (and thus has no optimizations run on it)
mir_for_ctfe_of_const_arg	Same as mir_for_ctfe, but used to get the MIR of a const generic parameter. The docs on WithOptConstParam explain this a bit more, but the TLDR is that we’d get cycle errors with mir_for_ctfe, because typeck would need to typeck the const parameter while type checking the main body, which in turn would try to type check the main body again.
mir_keys	Finds the full set of DefIds within the current crate that have MIR associated with them.
mir_promoted	Compute the main MIR body and the list of MIR bodies of the promoteds.
optimized_mir	Optimize the MIR and prepare it for codegen.
promoted_mir	Fetch all the promoteds of an item and prepare their MIR bodies to be ready for constant evaluation once all substitutions become known.
provide
run_optimization_passes
run_passes
run_post_borrowck_cleanup_passes	After this series of passes, no lifetime analysis based on borrowing can be done.