From 718a8d1c3836170eaee78d337a40e14d5a0adee6 Mon Sep 17 00:00:00 2001 From: Ralf Jung Date: Wed, 9 Aug 2017 11:30:55 -0700 Subject: [PATCH] run AddCallGuards for *all* call edges before running AddValidation --- src/librustc_driver/driver.rs | 11 +-- src/librustc_mir/shim.rs | 2 +- src/librustc_mir/transform/add_call_guards.rs | 79 +++++++++++-------- 3 files changed, 51 insertions(+), 41 deletions(-) diff --git a/src/librustc_driver/driver.rs b/src/librustc_driver/driver.rs index 12cb556afda..443bdf6a373 100644 --- a/src/librustc_driver/driver.rs +++ b/src/librustc_driver/driver.rs @@ -942,15 +942,16 @@ pub fn phase_3_run_analysis_passes<'tcx, F, R>(sess: &'tcx Session, // These next passes must be executed together passes.push_pass(MIR_OPTIMIZED, mir::transform::no_landing_pads::NoLandingPads); - passes.push_pass(MIR_OPTIMIZED, mir::transform::add_call_guards::AddCallGuards); + passes.push_pass(MIR_OPTIMIZED, mir::transform::add_call_guards::CriticalCallEdges); passes.push_pass(MIR_OPTIMIZED, mir::transform::elaborate_drops::ElaborateDrops); passes.push_pass(MIR_OPTIMIZED, mir::transform::no_landing_pads::NoLandingPads); + // AddValidation needs to run after ElaborateDrops and before EraseRegions, and it needs + // an AllCallEdges pass right before it. + passes.push_pass(MIR_OPTIMIZED, mir::transform::add_call_guards::AllCallEdges); + passes.push_pass(MIR_OPTIMIZED, mir::transform::add_validation::AddValidation); passes.push_pass(MIR_OPTIMIZED, mir::transform::simplify::SimplifyCfg::new("elaborate-drops")); // No lifetime analysis based on borrowing can be done from here on out. - // AddValidation needs to run after ElaborateDrops and before EraseRegions. - passes.push_pass(MIR_OPTIMIZED, mir::transform::add_validation::AddValidation); - // From here on out, regions are gone. passes.push_pass(MIR_OPTIMIZED, mir::transform::erase_regions::EraseRegions); @@ -960,7 +961,7 @@ pub fn phase_3_run_analysis_passes<'tcx, F, R>(sess: &'tcx Session, passes.push_pass(MIR_OPTIMIZED, mir::transform::deaggregator::Deaggregator); passes.push_pass(MIR_OPTIMIZED, mir::transform::copy_prop::CopyPropagation); passes.push_pass(MIR_OPTIMIZED, mir::transform::simplify::SimplifyLocals); - passes.push_pass(MIR_OPTIMIZED, mir::transform::add_call_guards::AddCallGuards); + passes.push_pass(MIR_OPTIMIZED, mir::transform::add_call_guards::CriticalCallEdges); passes.push_pass(MIR_OPTIMIZED, mir::transform::dump_mir::Marker("PreTrans")); TyCtxt::create_and_enter(sess, diff --git a/src/librustc_mir/shim.rs b/src/librustc_mir/shim.rs index 11ad5d1509d..62e762be93a 100644 --- a/src/librustc_mir/shim.rs +++ b/src/librustc_mir/shim.rs @@ -105,7 +105,7 @@ fn make_shim<'a, 'tcx>(tcx: ty::TyCtxt<'a, 'tcx, 'tcx>, debug!("make_shim({:?}) = untransformed {:?}", instance, result); no_landing_pads::no_landing_pads(tcx, &mut result); simplify::simplify_cfg(&mut result); - add_call_guards::add_call_guards(&mut result); + add_call_guards::CriticalCallEdges.add_call_guards(&mut result); debug!("make_shim({:?}) = {:?}", instance, result); tcx.alloc_mir(result) diff --git a/src/librustc_mir/transform/add_call_guards.rs b/src/librustc_mir/transform/add_call_guards.rs index b7c7a1774dd..23a9c4c57ca 100644 --- a/src/librustc_mir/transform/add_call_guards.rs +++ b/src/librustc_mir/transform/add_call_guards.rs @@ -13,7 +13,12 @@ use rustc::mir::*; use rustc::mir::transform::{MirPass, MirSource}; use rustc_data_structures::indexed_vec::{Idx, IndexVec}; -pub struct AddCallGuards; +#[derive(PartialEq)] +pub enum AddCallGuards { + AllCallEdges, + CriticalCallEdges, +} +pub use self::AddCallGuards::*; /** * Breaks outgoing critical edges for call terminators in the MIR. @@ -40,48 +45,52 @@ impl MirPass for AddCallGuards { _tcx: TyCtxt<'a, 'tcx, 'tcx>, _src: MirSource, mir: &mut Mir<'tcx>) { - add_call_guards(mir); + self.add_call_guards(mir); } } -pub fn add_call_guards(mir: &mut Mir) { - let pred_count: IndexVec<_, _> = - mir.predecessors().iter().map(|ps| ps.len()).collect(); +impl AddCallGuards { + pub fn add_call_guards(&self, mir: &mut Mir) { + let pred_count: IndexVec<_, _> = + mir.predecessors().iter().map(|ps| ps.len()).collect(); - // We need a place to store the new blocks generated - let mut new_blocks = Vec::new(); + // We need a place to store the new blocks generated + let mut new_blocks = Vec::new(); - let cur_len = mir.basic_blocks().len(); + let cur_len = mir.basic_blocks().len(); - for block in mir.basic_blocks_mut() { - match block.terminator { - Some(Terminator { - kind: TerminatorKind::Call { - destination: Some((_, ref mut destination)), - cleanup: Some(_), - .. - }, source_info - }) if pred_count[*destination] > 1 => { - // It's a critical edge, break it - let call_guard = BasicBlockData { - statements: vec![], - is_cleanup: block.is_cleanup, - terminator: Some(Terminator { - source_info: source_info, - kind: TerminatorKind::Goto { target: *destination } - }) - }; + for block in mir.basic_blocks_mut() { + match block.terminator { + Some(Terminator { + kind: TerminatorKind::Call { + destination: Some((_, ref mut destination)), + cleanup, + .. + }, source_info + }) if pred_count[*destination] > 1 && + (cleanup.is_some() || self == &AllCallEdges) => + { + // It's a critical edge, break it + let call_guard = BasicBlockData { + statements: vec![], + is_cleanup: block.is_cleanup, + terminator: Some(Terminator { + source_info: source_info, + kind: TerminatorKind::Goto { target: *destination } + }) + }; - // Get the index it will be when inserted into the MIR - let idx = cur_len + new_blocks.len(); - new_blocks.push(call_guard); - *destination = BasicBlock::new(idx); + // Get the index it will be when inserted into the MIR + let idx = cur_len + new_blocks.len(); + new_blocks.push(call_guard); + *destination = BasicBlock::new(idx); + } + _ => {} } - _ => {} } + + debug!("Broke {} N edges", new_blocks.len()); + + mir.basic_blocks_mut().extend(new_blocks); } - - debug!("Broke {} N edges", new_blocks.len()); - - mir.basic_blocks_mut().extend(new_blocks); }