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Auto merge of #106959 - tmiasko:opt-funclets, r=davidtwco

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Omit needless funclet partitioning
This commit is contained in:
bors 2023-01-27 03:25:16 +00:00
commit db137ba7d4
2 changed files with 40 additions and 43 deletions
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76
compiler/rustc_codegen_ssa/src/mir/block.rs
View File

@ -39,7 +39,6 @@ enum MergingSucc {
struct TerminatorCodegenHelper<'tcx> {
bb: mir::BasicBlock,
terminator: &'tcx mir::Terminator<'tcx>,
funclet_bb: Option<mir::BasicBlock>,
}
impl<'a, 'tcx> TerminatorCodegenHelper<'tcx> {
@ -49,28 +48,24 @@ fn funclet<'b, Bx: BuilderMethods<'a, 'tcx>>(
&self,
fx: &'b mut FunctionCx<'a, 'tcx, Bx>,
) -> Option<&'b Bx::Funclet> {
let funclet_bb = self.funclet_bb?;
if base::wants_msvc_seh(fx.cx.tcx().sess) {
// If `landing_pad_for` hasn't been called yet to create the `Funclet`,
// it has to be now. This may not seem necessary, as RPO should lead
// to all the unwind edges being visited (and so to `landing_pad_for`
// getting called for them), before building any of the blocks inside
// the funclet itself - however, if MIR contains edges that end up not
// being needed in the LLVM IR after monomorphization, the funclet may
// be unreachable, and we don't have yet a way to skip building it in
// such an eventuality (which may be a better solution than this).
if fx.funclets[funclet_bb].is_none() {
fx.landing_pad_for(funclet_bb);
}
Some(
fx.funclets[funclet_bb]
.as_ref()
.expect("landing_pad_for didn't also create funclets entry"),
)
} else {
None
let cleanup_kinds = (&fx.cleanup_kinds).as_ref()?;
let funclet_bb = cleanup_kinds[self.bb].funclet_bb(self.bb)?;
// If `landing_pad_for` hasn't been called yet to create the `Funclet`,
// it has to be now. This may not seem necessary, as RPO should lead
// to all the unwind edges being visited (and so to `landing_pad_for`
// getting called for them), before building any of the blocks inside
// the funclet itself - however, if MIR contains edges that end up not
// being needed in the LLVM IR after monomorphization, the funclet may
// be unreachable, and we don't have yet a way to skip building it in
// such an eventuality (which may be a better solution than this).
if fx.funclets[funclet_bb].is_none() {
fx.landing_pad_for(funclet_bb);
}
Some(
fx.funclets[funclet_bb]
.as_ref()
.expect("landing_pad_for didn't also create funclets entry"),
)
}
/// Get a basic block (creating it if necessary), possibly with cleanup
@ -104,23 +99,24 @@ fn llbb_characteristics<Bx: BuilderMethods<'a, 'tcx>>(
fx: &mut FunctionCx<'a, 'tcx, Bx>,
target: mir::BasicBlock,
) -> (bool, bool) {
let target_funclet = fx.cleanup_kinds[target].funclet_bb(target);
let (needs_landing_pad, is_cleanupret) = match (self.funclet_bb, target_funclet) {
(None, None) => (false, false),
(None, Some(_)) => (true, false),
(Some(_), None) => {
let span = self.terminator.source_info.span;
span_bug!(span, "{:?} - jump out of cleanup?", self.terminator);
}
(Some(f), Some(t_f)) => {
if f == t_f || !base::wants_msvc_seh(fx.cx.tcx().sess) {
(false, false)
} else {
(true, true)
if let Some(ref cleanup_kinds) = fx.cleanup_kinds {
let funclet_bb = cleanup_kinds[self.bb].funclet_bb(self.bb);
let target_funclet = cleanup_kinds[target].funclet_bb(target);
let (needs_landing_pad, is_cleanupret) = match (funclet_bb, target_funclet) {
(None, None) => (false, false),
(None, Some(_)) => (true, false),
(Some(f), Some(t_f)) => (f != t_f, f != t_f),
(Some(_), None) => {
let span = self.terminator.source_info.span;
span_bug!(span, "{:?} - jump out of cleanup?", self.terminator);
}
}
};
(needs_landing_pad, is_cleanupret)
};
(needs_landing_pad, is_cleanupret)
} else {
let needs_landing_pad = !fx.mir[self.bb].is_cleanup && fx.mir[target].is_cleanup;
let is_cleanupret = false;
(needs_landing_pad, is_cleanupret)
}
}
fn funclet_br<Bx: BuilderMethods<'a, 'tcx>>(
@ -1253,9 +1249,7 @@ fn codegen_terminator(
) -> MergingSucc {
debug!("codegen_terminator: {:?}", terminator);
// Create the cleanup bundle, if needed.
let funclet_bb = self.cleanup_kinds[bb].funclet_bb(bb);
let helper = TerminatorCodegenHelper { bb, terminator, funclet_bb };
let helper = TerminatorCodegenHelper { bb, terminator };
let mergeable_succ = || {
// Note: any call to `switch_to_block` will invalidate a `true` value

7
compiler/rustc_codegen_ssa/src/mir/mod.rs
View File

@ -1,3 +1,4 @@
use crate::base;
use crate::traits::*;
use rustc_middle::mir;
use rustc_middle::mir::interpret::ErrorHandled;
@ -58,7 +59,7 @@ pub struct FunctionCx<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> {
cached_llbbs: IndexVec<mir::BasicBlock, CachedLlbb<Bx::BasicBlock>>,
/// The funclet status of each basic block
cleanup_kinds: IndexVec<mir::BasicBlock, analyze::CleanupKind>,
cleanup_kinds: Option<IndexVec<mir::BasicBlock, analyze::CleanupKind>>,
/// When targeting MSVC, this stores the cleanup info for each funclet BB.
/// This is initialized at the same time as the `landing_pads` entry for the
@ -166,7 +167,9 @@ pub fn codegen_mir<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
start_bx.set_personality_fn(cx.eh_personality());
}
let cleanup_kinds = analyze::cleanup_kinds(&mir);
let cleanup_kinds =
if base::wants_msvc_seh(cx.tcx().sess) { Some(analyze::cleanup_kinds(&mir)) } else { None };
let cached_llbbs: IndexVec<mir::BasicBlock, CachedLlbb<Bx::BasicBlock>> =
mir.basic_blocks
.indices()