From fe2da30cb54aadeab243f3fc7bd3e14dd4da2892 Mon Sep 17 00:00:00 2001 From: sunnymilk Date: Tue, 10 Sep 2024 12:27:55 -0400 Subject: cmd/compile: keep variables alive in testing.B.Loop loops For the loop body guarded by testing.B.Loop, we disable function inlining and devirtualization inside. The only legal form to be matched is `for b.Loop() {...}`. For #61515 Change-Id: I2e226f08cb4614667cbded498a7821dffe3f72d8 Reviewed-on: https://go-review.googlesource.com/c/go/+/612043 Reviewed-by: Michael Pratt TryBot-Bypass: Junyang Shao Commit-Queue: Junyang Shao Reviewed-by: Cherry Mui --- .../internal/inline/interleaved/interleaved.go | 34 ++++++++++++++++++++++ 1 file changed, 34 insertions(+) (limited to 'src/cmd') diff --git a/src/cmd/compile/internal/inline/interleaved/interleaved.go b/src/cmd/compile/internal/inline/interleaved/interleaved.go index dc5c3b8969..a91ab23daa 100644 --- a/src/cmd/compile/internal/inline/interleaved/interleaved.go +++ b/src/cmd/compile/internal/inline/interleaved/interleaved.go @@ -105,6 +105,32 @@ func DevirtualizeAndInlineFunc(fn *ir.Func, profile *pgoir.Profile) { }) } +// isTestingBLoop returns true if it matches the node as a +// testing.(*B).Loop. See issue #61515. +func isTestingBLoop(t ir.Node) bool { + if t.Op() != ir.OFOR { + return false + } + nFor, ok := t.(*ir.ForStmt) + if !ok || nFor.Cond == nil || nFor.Cond.Op() != ir.OCALLFUNC { + return false + } + n, ok := nFor.Cond.(*ir.CallExpr) + if !ok || n.Fun == nil || n.Fun.Op() != ir.OMETHEXPR { + return false + } + name := ir.MethodExprName(n.Fun) + if name == nil { + return false + } + if fSym := name.Sym(); fSym != nil && name.Class == ir.PFUNC && fSym.Pkg != nil && + fSym.Name == "(*B).Loop" && fSym.Pkg.Path == "testing" { + // Attempting to match a function call to testing.(*B).Loop + return true + } + return false +} + // fixpoint repeatedly edits a function until it stabilizes. // // First, fixpoint applies match to every node n within fn. Then it @@ -133,6 +159,14 @@ func fixpoint(fn *ir.Func, match func(ir.Node) bool, edit func(ir.Node) ir.Node) return n // already visited n.X before wrapping } + if isTestingBLoop(n) { + // No inlining nor devirtualization performed on b.Loop body + if base.Flag.LowerM > 1 { + fmt.Printf("%v: skip inlining within testing.B.loop for %v\n", ir.Line(n), n) + } + return n + } + ok := match(n) // can't wrap TailCall's child into ParenExpr -- cgit v1.3