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Add is_recursive_terminator() helper for unconditional_recursion lint

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This commit is contained in:
Martin Nordholts 2023-07-20 16:29:26 +02:00
parent f92d6699b8
commit eed34b8bc1
1 changed files with 13 additions and 10 deletions
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21
compiler/rustc_mir_build/src/lints.rs
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@ -3,7 +3,7 @@ use rustc_data_structures::graph::iterate::{
NodeStatus, TriColorDepthFirstSearch, TriColorVisitor, NodeStatus, TriColorDepthFirstSearch, TriColorVisitor,
}; };
use rustc_hir::def::DefKind; use rustc_hir::def::DefKind;
use rustc_middle::mir::{self, BasicBlock, BasicBlocks, Body, Operand, TerminatorKind}; use rustc_middle::mir::{self, BasicBlock, BasicBlocks, Body, Operand, Terminator, TerminatorKind};
use rustc_middle::ty::{self, Instance, TyCtxt}; use rustc_middle::ty::{self, Instance, TyCtxt};
use rustc_middle::ty::{GenericArg, GenericArgs}; use rustc_middle::ty::{GenericArg, GenericArgs};
use rustc_session::lint::builtin::UNCONDITIONAL_RECURSION; use rustc_session::lint::builtin::UNCONDITIONAL_RECURSION;
@ -57,6 +57,13 @@ struct Search<'mir, 'tcx> {
} }
impl<'mir, 'tcx> Search<'mir, 'tcx> { impl<'mir, 'tcx> Search<'mir, 'tcx> {
fn is_recursive_terminator(&self, terminator: &Terminator<'tcx>) -> bool {
match &terminator.kind {
TerminatorKind::Call { func, args, .. } => self.is_recursive_call(func, args),
_ => false,
}
}
/// Returns `true` if `func` refers to the function we are searching in. /// Returns `true` if `func` refers to the function we are searching in.
fn is_recursive_call(&self, func: &Operand<'tcx>, args: &[Operand<'tcx>]) -> bool { fn is_recursive_call(&self, func: &Operand<'tcx>, args: &[Operand<'tcx>]) -> bool {
let Search { tcx, body, trait_args, .. } = *self; let Search { tcx, body, trait_args, .. } = *self;
@ -138,25 +145,21 @@ impl<'mir, 'tcx> TriColorVisitor<BasicBlocks<'tcx>> for Search<'mir, 'tcx> {
fn node_settled(&mut self, bb: BasicBlock) -> ControlFlow<Self::BreakVal> { fn node_settled(&mut self, bb: BasicBlock) -> ControlFlow<Self::BreakVal> {
// When we examine a node for the last time, remember it if it is a recursive call. // When we examine a node for the last time, remember it if it is a recursive call.
let terminator = self.body[bb].terminator(); let terminator = self.body[bb].terminator();
if let TerminatorKind::Call { func, args, .. } = &terminator.kind { if self.is_recursive_terminator(terminator) {
if self.is_recursive_call(func, args) {
self.reachable_recursive_calls.push(terminator.source_info.span); self.reachable_recursive_calls.push(terminator.source_info.span);
} }
}
ControlFlow::Continue(()) ControlFlow::Continue(())
} }
fn ignore_edge(&mut self, bb: BasicBlock, target: BasicBlock) -> bool { fn ignore_edge(&mut self, bb: BasicBlock, target: BasicBlock) -> bool {
let terminator = self.body[bb].terminator(); let terminator = self.body[bb].terminator();
if terminator.unwind() == Some(&mir::UnwindAction::Cleanup(target)) let ignore_unwind = terminator.unwind() == Some(&mir::UnwindAction::Cleanup(target))
&& terminator.successors().count() > 1 && terminator.successors().count() > 1;
{ if ignore_unwind || self.is_recursive_terminator(terminator) {
return true; return true;
} }
// Don't traverse successors of recursive calls or false CFG edges.
match &terminator.kind { match &terminator.kind {
TerminatorKind::Call { func, args, .. } => self.is_recursive_call(func, args),
TerminatorKind::FalseEdge { imaginary_target, .. } => imaginary_target == &target, TerminatorKind::FalseEdge { imaginary_target, .. } => imaginary_target == &target,
_ => false, _ => false,
} }