From c46ebec322b4f61a219f73f3f0f590cf001a074d Mon Sep 17 00:00:00 2001 From: Keith Randall Date: Tue, 2 Apr 2019 15:00:54 -0700 Subject: [PATCH] cmd/compile: get rid of unnecessary inline marks If no other instruction mentions an inline mark, we can get rid of it. This normally happens when the inlined function is empty, or when all of its code is folded into other instructions. Also use consistent statement-ness for inline mark positions, so that more of them can be removed in favor of existing instructions. Update #29571 Fixes #31172 Change-Id: I71f84d355101f37a27960d9e8528f42f92767496 Reviewed-on: https://go-review.googlesource.com/c/go/+/170445 Run-TryBot: Keith Randall TryBot-Result: Gobot Gobot Reviewed-by: Josh Bleecher Snyder --- src/cmd/compile/internal/gc/inl.go | 2 +- src/cmd/compile/internal/ssa/deadcode.go | 31 ++++++++++++++++++++++++ 2 files changed, 32 insertions(+), 1 deletion(-) diff --git a/src/cmd/compile/internal/gc/inl.go b/src/cmd/compile/internal/gc/inl.go index 88c294173b..38be394bfb 100644 --- a/src/cmd/compile/internal/gc/inl.go +++ b/src/cmd/compile/internal/gc/inl.go @@ -1054,7 +1054,7 @@ func mkinlcall(n, fn *Node, maxCost int32) *Node { // to put a breakpoint. Not sure if that's really necessary or not // (in which case it could go at the end of the function instead). inlMark := nod(OINLMARK, nil, nil) - inlMark.Pos = n.Pos + inlMark.Pos = n.Pos.WithDefaultStmt() inlMark.Xoffset = int64(newIndex) ninit.Append(inlMark) diff --git a/src/cmd/compile/internal/ssa/deadcode.go b/src/cmd/compile/internal/ssa/deadcode.go index 3c0f8f858a..ceb2933766 100644 --- a/src/cmd/compile/internal/ssa/deadcode.go +++ b/src/cmd/compile/internal/ssa/deadcode.go @@ -76,6 +76,30 @@ func liveValues(f *Func, reachable []bool) (live []bool, liveOrderStmts []*Value return } + // Record all the inline indexes we need + var liveInlIdx map[int]bool + pt := f.Config.ctxt.PosTable + for _, b := range f.Blocks { + for _, v := range b.Values { + i := pt.Pos(v.Pos).Base().InliningIndex() + if i < 0 { + continue + } + if liveInlIdx == nil { + liveInlIdx = map[int]bool{} + } + liveInlIdx[i] = true + } + i := pt.Pos(b.Pos).Base().InliningIndex() + if i < 0 { + continue + } + if liveInlIdx == nil { + liveInlIdx = map[int]bool{} + } + liveInlIdx[i] = true + } + // Find all live values q := f.Cache.deadcode.q[:0] defer func() { f.Cache.deadcode.q = q }() @@ -103,6 +127,13 @@ func liveValues(f *Func, reachable []bool) (live []bool, liveOrderStmts []*Value } if v.Type.IsVoid() && !live[v.ID] { // The only Void ops are nil checks and inline marks. We must keep these. + if v.Op == OpInlMark && !liveInlIdx[int(v.AuxInt)] { + // We don't need marks for bodies that + // have been completely optimized away. + // TODO: save marks only for bodies which + // have a faulting instruction or a call? + continue + } live[v.ID] = true q = append(q, v) if v.Pos.IsStmt() != src.PosNotStmt { -- 2.50.0