From 5dac279fbdd8a4273253de98a4e44484b20bec5b Mon Sep 17 00:00:00 2001 From: Matthew Dempsky Date: Fri, 2 Jul 2021 16:29:42 -0700 Subject: [PATCH] [dev.typeparams] cmd/compile: formalize "hidden parameters" idea This CL formalizes the closure-var trick used for method-value wrappers to be reusable for defining other functions that take hidden parameters via the closure-context register. In particular, it: 1. Adds a new ir.NewHiddenParam function for creating hidden parameters. 2. Changes ir.NewClosureVar to copy Type/Typecheck from the closure variable, so that callers can needing to manually copy these. 3. Updates existing code accordingly (i.e., method-value wrappers to start using ir.NewHiddenParam, and closure builders to stop copying types). Longer term, I anticipate using this to pass dictionaries to stenciled functions within unified IR. Change-Id: I9da3ffdb2a26d15c6e89a21b4e080686d6dc872c Reviewed-on: https://go-review.googlesource.com/c/go/+/332612 Trust: Matthew Dempsky Run-TryBot: Matthew Dempsky TryBot-Result: Go Bot Reviewed-by: Cuong Manh Le --- src/cmd/compile/internal/escape/call.go | 4 +--- src/cmd/compile/internal/escape/escape.go | 10 ++++++-- src/cmd/compile/internal/escape/expr.go | 3 --- src/cmd/compile/internal/escape/graph.go | 8 +++++-- src/cmd/compile/internal/ir/name.go | 24 ++++++++++++++++++- src/cmd/compile/internal/noder/reader.go | 15 ++---------- src/cmd/compile/internal/typecheck/iimport.go | 9 ++----- src/cmd/compile/internal/walk/closure.go | 9 +------ 8 files changed, 43 insertions(+), 39 deletions(-) diff --git a/src/cmd/compile/internal/escape/call.go b/src/cmd/compile/internal/escape/call.go index 46bfe65aff..5bd748027e 100644 --- a/src/cmd/compile/internal/escape/call.go +++ b/src/cmd/compile/internal/escape/call.go @@ -343,9 +343,7 @@ func (e *escape) wrapExpr(pos src.XPos, exprp *ir.Node, init *ir.Nodes, call ir. e.oldLoc(tmp).captured = true - cv := ir.NewClosureVar(pos, wrapper, tmp) - cv.SetType(tmp.Type()) - tmp = typecheck.Expr(cv).(*ir.Name) + tmp = ir.NewClosureVar(pos, wrapper, tmp) } *exprp = tmp diff --git a/src/cmd/compile/internal/escape/escape.go b/src/cmd/compile/internal/escape/escape.go index 04d0c2356c..61e0121a40 100644 --- a/src/cmd/compile/internal/escape/escape.go +++ b/src/cmd/compile/internal/escape/escape.go @@ -183,8 +183,14 @@ func (b *batch) initFunc(fn *ir.Func) { // Allocate locations for local variables. for _, n := range fn.Dcl { - if n.Op() == ir.ONAME { - e.newLoc(n, false) + e.newLoc(n, false) + } + + // Also for hidden parameters (e.g., the ".this" parameter to a + // method value wrapper). + if fn.OClosure == nil { + for _, n := range fn.ClosureVars { + e.newLoc(n.Canonical(), false) } } diff --git a/src/cmd/compile/internal/escape/expr.go b/src/cmd/compile/internal/escape/expr.go index dfcd55734a..c2a679d474 100644 --- a/src/cmd/compile/internal/escape/expr.go +++ b/src/cmd/compile/internal/escape/expr.go @@ -46,9 +46,6 @@ func (e *escape) exprSkipInit(k hole, n ir.Node) { if n.Class == ir.PFUNC || n.Class == ir.PEXTERN { return } - if n.IsClosureVar() && n.Defn == nil { - return // ".this" from method value wrapper - } e.flow(k, e.oldLoc(n)) case ir.OPLUS, ir.ONEG, ir.OBITNOT, ir.ONOT: diff --git a/src/cmd/compile/internal/escape/graph.go b/src/cmd/compile/internal/escape/graph.go index 6316435dfe..d3ae1da693 100644 --- a/src/cmd/compile/internal/escape/graph.go +++ b/src/cmd/compile/internal/escape/graph.go @@ -222,7 +222,9 @@ func (e *escape) newLoc(n ir.Node, transient bool) *location { } if n != nil && n.Op() == ir.ONAME { - n = n.(*ir.Name).Canonical() + if canon := n.(*ir.Name).Canonical(); n != canon { + base.Fatalf("newLoc on non-canonical %v (canonical is %v)", n, canon) + } } loc := &location{ n: n, @@ -234,7 +236,9 @@ func (e *escape) newLoc(n ir.Node, transient bool) *location { if n != nil { if n.Op() == ir.ONAME { n := n.(*ir.Name) - if n.Curfn != e.curfn { + if n.Class == ir.PPARAM && n.Curfn == nil { + // ok; hidden parameter + } else if n.Curfn != e.curfn { base.Fatalf("curfn mismatch: %v != %v for %v", n.Curfn, e.curfn, n) } diff --git a/src/cmd/compile/internal/ir/name.go b/src/cmd/compile/internal/ir/name.go index ff9784df1b..a2eec05013 100644 --- a/src/cmd/compile/internal/ir/name.go +++ b/src/cmd/compile/internal/ir/name.go @@ -358,7 +358,7 @@ func (n *Name) Byval() bool { return n.Canonical().flags&nameByval != 0 } -// NewClosureVar creates a new closure variable for fn to refer to +// NewClosureVar returns a new closure variable for fn to refer to // outer variable n. func NewClosureVar(pos src.XPos, fn *Func, n *Name) *Name { c := NewNameAt(pos, n.Sym()) @@ -368,11 +368,33 @@ func NewClosureVar(pos src.XPos, fn *Func, n *Name) *Name { c.Defn = n.Canonical() c.Outer = n + c.SetType(n.Type()) + c.SetTypecheck(n.Typecheck()) + fn.ClosureVars = append(fn.ClosureVars, c) return c } +// NewHiddenParam returns a new hidden parameter for fn with the given +// name and type. +func NewHiddenParam(pos src.XPos, fn *Func, sym *types.Sym, typ *types.Type) *Name { + if fn.OClosure != nil { + base.FatalfAt(fn.Pos(), "cannot add hidden parameters to closures") + } + + fn.SetNeedctxt(true) + + // Create a fake parameter, disassociated from any real function, to + // pretend to capture. + fake := NewNameAt(pos, sym) + fake.Class = PPARAM + fake.SetType(typ) + fake.SetByval(true) + + return NewClosureVar(pos, fn, fake) +} + // CaptureName returns a Name suitable for referring to n from within function // fn or from the package block if fn is nil. If n is a free variable declared // within a function that encloses fn, then CaptureName returns the closure diff --git a/src/cmd/compile/internal/noder/reader.go b/src/cmd/compile/internal/noder/reader.go index 275baead04..14d982a1af 100644 --- a/src/cmd/compile/internal/noder/reader.go +++ b/src/cmd/compile/internal/noder/reader.go @@ -1623,11 +1623,7 @@ func (r *reader) funcLit() ir.Node { fn.ClosureVars = make([]*ir.Name, 0, r.len()) for len(fn.ClosureVars) < cap(fn.ClosureVars) { - pos := r.pos() - outer := r.useLocal() - - cv := ir.NewClosureVar(pos, fn, outer) - r.setType(cv, outer.Type()) + ir.NewClosureVar(r.pos(), fn, r.useLocal()) } r.addBody(fn) @@ -2204,17 +2200,10 @@ func (r *reader) methodValueWrapper(tbase *types.Type, method *types.Field, targ pos := base.AutogeneratedPos fn := r.newWrapperFunc(pos, sym, nil, method) - fn.SetNeedctxt(true) sym.Def = fn // Declare and initialize variable holding receiver. - recv := ir.NewNameAt(pos, typecheck.Lookup(".this")) - recv.Class = ir.PAUTOHEAP - recv.SetType(recvType) - recv.Curfn = fn - recv.SetIsClosureVar(true) - recv.SetByval(true) - fn.ClosureVars = append(fn.ClosureVars, recv) + recv := ir.NewHiddenParam(pos, fn, typecheck.Lookup(".this"), recvType) addTailCall(pos, fn, recv, method) diff --git a/src/cmd/compile/internal/typecheck/iimport.go b/src/cmd/compile/internal/typecheck/iimport.go index 7b61260e79..a45bbfd1f8 100644 --- a/src/cmd/compile/internal/typecheck/iimport.go +++ b/src/cmd/compile/internal/typecheck/iimport.go @@ -1289,13 +1289,8 @@ func (r *importReader) node() ir.Node { cvars := make([]*ir.Name, r.int64()) for i := range cvars { cvars[i] = ir.CaptureName(r.pos(), fn, r.localName().Canonical()) - if go117ExportTypes { - if cvars[i].Type() != nil || cvars[i].Defn == nil { - base.Fatalf("bad import of closure variable") - } - // Closure variable should have Defn set, which is its captured - // variable, and it gets the same type as the captured variable. - cvars[i].SetType(cvars[i].Defn.Type()) + if go117ExportTypes && cvars[i].Defn == nil { + base.Fatalf("bad import of closure variable") } } fn.ClosureVars = cvars diff --git a/src/cmd/compile/internal/walk/closure.go b/src/cmd/compile/internal/walk/closure.go index a86ed2ab80..7f6ef473bf 100644 --- a/src/cmd/compile/internal/walk/closure.go +++ b/src/cmd/compile/internal/walk/closure.go @@ -238,17 +238,10 @@ func methodValueWrapper(dot *ir.SelectorExpr) *ir.Func { fn := typecheck.DeclFunc(sym, tfn) fn.SetDupok(true) - fn.SetNeedctxt(true) fn.SetWrapper(true) // Declare and initialize variable holding receiver. - ptr := ir.NewNameAt(base.Pos, typecheck.Lookup(".this")) - ptr.Class = ir.PAUTOHEAP - ptr.SetType(rcvrtype) - ptr.Curfn = fn - ptr.SetIsClosureVar(true) - ptr.SetByval(true) - fn.ClosureVars = append(fn.ClosureVars, ptr) + ptr := ir.NewHiddenParam(base.Pos, fn, typecheck.Lookup(".this"), rcvrtype) call := ir.NewCallExpr(base.Pos, ir.OCALL, ir.NewSelectorExpr(base.Pos, ir.OXDOT, ptr, meth), nil) call.Args = ir.ParamNames(tfn.Type())