diff options
| -rw-r--r-- | src/librustc_mir/transform/inline.rs | 29 |
1 files changed, 23 insertions, 6 deletions
diff --git a/src/librustc_mir/transform/inline.rs b/src/librustc_mir/transform/inline.rs index f2453d39461..95e9c8f6df8 100644 --- a/src/librustc_mir/transform/inline.rs +++ b/src/librustc_mir/transform/inline.rs @@ -37,7 +37,7 @@ const UNKNOWN_SIZE_COST: usize = 10; pub struct Inline; -#[derive(Copy, Clone)] +#[derive(Copy, Clone, Debug)] struct CallSite<'tcx> { callee: DefId, substs: &'tcx Substs<'tcx>, @@ -113,7 +113,9 @@ impl<'a, 'tcx> Inliner<'a, 'tcx> { loop { local_change = false; while let Some(callsite) = callsites.pop_front() { + debug!("checking whether to inline callsite {:?}", callsite); if !self.tcx.is_mir_available(callsite.callee) { + debug!("checking whether to inline callsite {:?} - MIR unavailable", callsite); continue; } @@ -133,10 +135,12 @@ impl<'a, 'tcx> Inliner<'a, 'tcx> { }; let start = caller_mir.basic_blocks().len(); - + debug!("attempting to inline callsite {:?} - mir={:?}", callsite, callee_mir); if !self.inline_call(callsite, caller_mir, callee_mir) { + debug!("attempting to inline callsite {:?} - failure", callsite); continue; } + debug!("attempting to inline callsite {:?} - success", callsite); // Add callsites from inlined function for (bb, bb_data) in caller_mir.basic_blocks().iter_enumerated().skip(start) { @@ -180,16 +184,19 @@ impl<'a, 'tcx> Inliner<'a, 'tcx> { callee_mir: &Mir<'tcx>) -> bool { + debug!("should_inline({:?})", callsite); let tcx = self.tcx; // Don't inline closures that have captures // FIXME: Handle closures better if callee_mir.upvar_decls.len() > 0 { + debug!(" upvar decls present - not inlining"); return false; } // Cannot inline generators which haven't been transformed yet if callee_mir.yield_ty.is_some() { + debug!(" yield ty present - not inlining"); return false; } @@ -201,7 +208,10 @@ impl<'a, 'tcx> Inliner<'a, 'tcx> { // there are cases that prevent inlining that we // need to check for first. attr::InlineAttr::Always => true, - attr::InlineAttr::Never => return false, + attr::InlineAttr::Never => { + debug!("#[inline(never)] present - not inlining"); + return false + } attr::InlineAttr::Hint => true, attr::InlineAttr::None => false, }; @@ -211,6 +221,7 @@ impl<'a, 'tcx> Inliner<'a, 'tcx> { // reference unexported symbols if callsite.callee.is_local() { if callsite.substs.types().count() == 0 && !hinted { + debug!(" callee is an exported function - not inlining"); return false; } } @@ -232,6 +243,7 @@ impl<'a, 'tcx> Inliner<'a, 'tcx> { if callee_mir.basic_blocks().len() <= 3 { threshold += threshold / 4; } + debug!(" final inline threshold = {}", threshold); // FIXME: Give a bonus to functions with only a single caller @@ -327,12 +339,17 @@ impl<'a, 'tcx> Inliner<'a, 'tcx> { } } - debug!("Inline cost for {:?} is {}", callsite.callee, cost); - if let attr::InlineAttr::Always = hint { + debug!("INLINING {:?} because inline(always) [cost={}]", callsite, cost); true } else { - cost <= threshold + if cost <= threshold { + debug!("INLINING {:?} [cost={} <= threshold={}]", callsite, cost, threshold); + true + } else { + debug!("NOT inlining {:?} [cost={} > threshold={}]", callsite, cost, threshold); + false + } } } |