From 7c8a9615c0512815060489a491265c275127b79f Mon Sep 17 00:00:00 2001 From: Matthew Dempsky Date: Mon, 18 Sep 2017 23:02:02 -0700 Subject: [PATCH] cmd/compile: fix stack frame info for calls in receiver slot Previously, after inlining a call, we made a second pass to rewrite the AST's position information to record the inlined stack frame. The call arguments were part of this AST, but it would be incorrect to rewrite them too, so extra effort was made to temporarily remove them while the position rewriting was done. However, this extra logic was only done for regular arguments: it was not done for receiver arguments. Consequently if m was inlined in "f().m(g(), h())", g and h would have correct call frames, but f would appear to be called by m. The fix taken by this CL is to merge setpos into inlsubst and only rewrite position information for nodes that were actually copied from the original function AST body. As a side benefit, this eliminates an extra AST pass and some AST walking code. Fixes #21879. Change-Id: I22b25c208313fc25c358d3a2eebfc9b012400084 Reviewed-on: https://go-review.googlesource.com/64470 Run-TryBot: Matthew Dempsky TryBot-Result: Gobot Gobot Reviewed-by: Robert Griesemer --- src/cmd/compile/internal/gc/inl.go | 94 +++++++++--------------------- test/fixedbugs/issue21879.go | 37 ++++++++++++ test/fixedbugs/issue21879.out | 2 + 3 files changed, 65 insertions(+), 68 deletions(-) create mode 100644 test/fixedbugs/issue21879.go create mode 100644 test/fixedbugs/issue21879.out diff --git a/src/cmd/compile/internal/gc/inl.go b/src/cmd/compile/internal/gc/inl.go index f9f273f5a8..3a34ab9246 100644 --- a/src/cmd/compile/internal/gc/inl.go +++ b/src/cmd/compile/internal/gc/inl.go @@ -740,10 +740,18 @@ func mkinlcall1(n *Node, fn *Node, isddd bool) *Node { inlgen++ + parent := -1 + if b := Ctxt.PosTable.Pos(n.Pos).Base(); b != nil { + parent = b.InliningIndex() + } + newIndex := Ctxt.InlTree.Add(parent, n.Pos, fn.Sym.Linksym()) + subst := inlsubst{ - retlabel: retlabel, - retvars: retvars, - inlvars: inlvars, + retlabel: retlabel, + retvars: retvars, + inlvars: inlvars, + bases: make(map[*src.PosBase]*src.PosBase), + newInlIndex: newIndex, } body := subst.list(fn.Func.Inl) @@ -762,28 +770,6 @@ func mkinlcall1(n *Node, fn *Node, isddd bool) *Node { call.Type = n.Type call.SetTypecheck(1) - // Hide the args from setPos -- the parameters to the inlined - // call already have good line numbers that should be preserved. - args := as.Rlist - as.Rlist.Set(nil) - - // Rewrite the line information for the inlined AST. - parent := -1 - callBase := Ctxt.PosTable.Pos(n.Pos).Base() - if callBase != nil { - parent = callBase.InliningIndex() - } - newIndex := Ctxt.InlTree.Add(parent, n.Pos, fn.Sym.Linksym()) - setpos := &setPos{ - bases: make(map[*src.PosBase]*src.PosBase), - newInlIndex: newIndex, - } - setpos.node(call) - - as.Rlist.Set(args.Slice()) - - //dumplist("call body", body); - n = call // transitive inlining @@ -861,6 +847,14 @@ type inlsubst struct { retvars []*Node inlvars map[*Node]*Node + + // bases maps from original PosBase to PosBase with an extra + // inlined call frame. + bases map[*src.PosBase]*src.PosBase + + // newInlIndex is the index of the inlined call frame to + // insert for inlined nodes. + newInlIndex int } // list inlines a list of nodes. @@ -908,7 +902,6 @@ func (subst *inlsubst) node(n *Node) *Node { // dump("Return before substitution", n); case ORETURN: m := nod(OGOTO, subst.retlabel, nil) - m.Ninit.Set(subst.list(n.Ninit)) if len(subst.retvars) != 0 && n.List.Len() != 0 { @@ -934,6 +927,7 @@ func (subst *inlsubst) node(n *Node) *Node { case OGOTO, OLABEL: m := nod(OXXX, nil, nil) *m = *n + m.Pos = subst.updatedPos(m.Pos) m.Ninit.Set(nil) p := fmt.Sprintf("%s·%d", n.Left.Sym.Name, inlgen) m.Left = newname(lookup(p)) @@ -943,6 +937,7 @@ func (subst *inlsubst) node(n *Node) *Node { m := nod(OXXX, nil, nil) *m = *n + m.Pos = subst.updatedPos(m.Pos) m.Ninit.Set(nil) if n.Op == OCLOSURE { @@ -959,50 +954,13 @@ func (subst *inlsubst) node(n *Node) *Node { return m } -// setPos is a visitor to update position info with a new inlining index. -type setPos struct { - bases map[*src.PosBase]*src.PosBase - newInlIndex int -} - -func (s *setPos) nodelist(ll Nodes) { - for _, n := range ll.Slice() { - s.node(n) - } -} - -func (s *setPos) node(n *Node) { - if n == nil { - return - } - if n.Op == OLITERAL || n.Op == OTYPE { - if n.Sym != nil { - // This node is not a copy, so don't clobber position. - return - } - } - - // don't clobber names, unless they're freshly synthesized - if n.Op != ONAME || !n.Pos.IsKnown() { - n.Pos = s.updatedPos(n) - } - - s.node(n.Left) - s.node(n.Right) - s.nodelist(n.List) - s.nodelist(n.Rlist) - s.nodelist(n.Ninit) - s.nodelist(n.Nbody) -} - -func (s *setPos) updatedPos(n *Node) src.XPos { - pos := Ctxt.PosTable.Pos(n.Pos) +func (subst *inlsubst) updatedPos(xpos src.XPos) src.XPos { + pos := Ctxt.PosTable.Pos(xpos) oldbase := pos.Base() // can be nil - newbase := s.bases[oldbase] + newbase := subst.bases[oldbase] if newbase == nil { - newbase = src.NewInliningBase(oldbase, s.newInlIndex) - pos.SetBase(newbase) - s.bases[oldbase] = newbase + newbase = src.NewInliningBase(oldbase, subst.newInlIndex) + subst.bases[oldbase] = newbase } pos.SetBase(newbase) return Ctxt.PosTable.XPos(pos) diff --git a/test/fixedbugs/issue21879.go b/test/fixedbugs/issue21879.go new file mode 100644 index 0000000000..1029ca044b --- /dev/null +++ b/test/fixedbugs/issue21879.go @@ -0,0 +1,37 @@ +// run + +// Copyright 2017 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package main + +import ( + "runtime" +) + +func main() { + println(caller().frame.Function) + + // Used to erroneously print "main.call.name" instead of + // "main.main". + println(caller().name()) +} + +func caller() call { + var pcs [3]uintptr + n := runtime.Callers(1, pcs[:]) + frames := runtime.CallersFrames(pcs[:n]) + frame, _ := frames.Next() + frame, _ = frames.Next() + + return call{frame: frame} +} + +type call struct { + frame runtime.Frame +} + +func (c call) name() string { + return c.frame.Function +} diff --git a/test/fixedbugs/issue21879.out b/test/fixedbugs/issue21879.out new file mode 100644 index 0000000000..066f1a8387 --- /dev/null +++ b/test/fixedbugs/issue21879.out @@ -0,0 +1,2 @@ +main.main +main.main -- 2.48.1