diff options
Diffstat (limited to 'src/cmd/compile/internal/escape/stmt.go')
| -rw-r--r-- | src/cmd/compile/internal/escape/stmt.go | 208 |
1 files changed, 208 insertions, 0 deletions
diff --git a/src/cmd/compile/internal/escape/stmt.go b/src/cmd/compile/internal/escape/stmt.go new file mode 100644 index 0000000..0afb5d6 --- /dev/null +++ b/src/cmd/compile/internal/escape/stmt.go @@ -0,0 +1,208 @@ +// Copyright 2018 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 escape + +import ( + "cmd/compile/internal/base" + "cmd/compile/internal/ir" + "fmt" +) + +// stmt evaluates a single Go statement. +func (e *escape) stmt(n ir.Node) { + if n == nil { + return + } + + lno := ir.SetPos(n) + defer func() { + base.Pos = lno + }() + + if base.Flag.LowerM > 2 { + fmt.Printf("%v:[%d] %v stmt: %v\n", base.FmtPos(base.Pos), e.loopDepth, e.curfn, n) + } + + e.stmts(n.Init()) + + switch n.Op() { + default: + base.Fatalf("unexpected stmt: %v", n) + + case ir.ODCLCONST, ir.ODCLTYPE, ir.OFALL, ir.OINLMARK: + // nop + + case ir.OBREAK, ir.OCONTINUE, ir.OGOTO: + // TODO(mdempsky): Handle dead code? + + case ir.OBLOCK: + n := n.(*ir.BlockStmt) + e.stmts(n.List) + + case ir.ODCL: + // Record loop depth at declaration. + n := n.(*ir.Decl) + if !ir.IsBlank(n.X) { + e.dcl(n.X) + } + + case ir.OLABEL: + n := n.(*ir.LabelStmt) + switch e.labels[n.Label] { + case nonlooping: + if base.Flag.LowerM > 2 { + fmt.Printf("%v:%v non-looping label\n", base.FmtPos(base.Pos), n) + } + case looping: + if base.Flag.LowerM > 2 { + fmt.Printf("%v: %v looping label\n", base.FmtPos(base.Pos), n) + } + e.loopDepth++ + default: + base.Fatalf("label missing tag") + } + delete(e.labels, n.Label) + + case ir.OIF: + n := n.(*ir.IfStmt) + e.discard(n.Cond) + e.block(n.Body) + e.block(n.Else) + + case ir.OFOR, ir.OFORUNTIL: + n := n.(*ir.ForStmt) + e.loopDepth++ + e.discard(n.Cond) + e.stmt(n.Post) + e.block(n.Body) + e.loopDepth-- + + case ir.ORANGE: + // for Key, Value = range X { Body } + n := n.(*ir.RangeStmt) + + // X is evaluated outside the loop. + tmp := e.newLoc(nil, false) + e.expr(tmp.asHole(), n.X) + + e.loopDepth++ + ks := e.addrs([]ir.Node{n.Key, n.Value}) + if n.X.Type().IsArray() { + e.flow(ks[1].note(n, "range"), tmp) + } else { + e.flow(ks[1].deref(n, "range-deref"), tmp) + } + e.reassigned(ks, n) + + e.block(n.Body) + e.loopDepth-- + + case ir.OSWITCH: + n := n.(*ir.SwitchStmt) + + if guard, ok := n.Tag.(*ir.TypeSwitchGuard); ok { + var ks []hole + if guard.Tag != nil { + for _, cas := range n.Cases { + cv := cas.Var + k := e.dcl(cv) // type switch variables have no ODCL. + if cv.Type().HasPointers() { + ks = append(ks, k.dotType(cv.Type(), cas, "switch case")) + } + } + } + e.expr(e.teeHole(ks...), n.Tag.(*ir.TypeSwitchGuard).X) + } else { + e.discard(n.Tag) + } + + for _, cas := range n.Cases { + e.discards(cas.List) + e.block(cas.Body) + } + + case ir.OSELECT: + n := n.(*ir.SelectStmt) + for _, cas := range n.Cases { + e.stmt(cas.Comm) + e.block(cas.Body) + } + case ir.ORECV: + // TODO(mdempsky): Consider e.discard(n.Left). + n := n.(*ir.UnaryExpr) + e.exprSkipInit(e.discardHole(), n) // already visited n.Ninit + case ir.OSEND: + n := n.(*ir.SendStmt) + e.discard(n.Chan) + e.assignHeap(n.Value, "send", n) + + case ir.OAS: + n := n.(*ir.AssignStmt) + e.assignList([]ir.Node{n.X}, []ir.Node{n.Y}, "assign", n) + case ir.OASOP: + n := n.(*ir.AssignOpStmt) + // TODO(mdempsky): Worry about OLSH/ORSH? + e.assignList([]ir.Node{n.X}, []ir.Node{n.Y}, "assign", n) + case ir.OAS2: + n := n.(*ir.AssignListStmt) + e.assignList(n.Lhs, n.Rhs, "assign-pair", n) + + case ir.OAS2DOTTYPE: // v, ok = x.(type) + n := n.(*ir.AssignListStmt) + e.assignList(n.Lhs, n.Rhs, "assign-pair-dot-type", n) + case ir.OAS2MAPR: // v, ok = m[k] + n := n.(*ir.AssignListStmt) + e.assignList(n.Lhs, n.Rhs, "assign-pair-mapr", n) + case ir.OAS2RECV, ir.OSELRECV2: // v, ok = <-ch + n := n.(*ir.AssignListStmt) + e.assignList(n.Lhs, n.Rhs, "assign-pair-receive", n) + + case ir.OAS2FUNC: + n := n.(*ir.AssignListStmt) + e.stmts(n.Rhs[0].Init()) + ks := e.addrs(n.Lhs) + e.call(ks, n.Rhs[0]) + e.reassigned(ks, n) + case ir.ORETURN: + n := n.(*ir.ReturnStmt) + results := e.curfn.Type().Results().FieldSlice() + dsts := make([]ir.Node, len(results)) + for i, res := range results { + dsts[i] = res.Nname.(*ir.Name) + } + e.assignList(dsts, n.Results, "return", n) + case ir.OCALLFUNC, ir.OCALLMETH, ir.OCALLINTER, ir.OINLCALL, ir.OCLOSE, ir.OCOPY, ir.ODELETE, ir.OPANIC, ir.OPRINT, ir.OPRINTN, ir.ORECOVER: + e.call(nil, n) + case ir.OGO, ir.ODEFER: + n := n.(*ir.GoDeferStmt) + e.goDeferStmt(n) + + case ir.OTAILCALL: + n := n.(*ir.TailCallStmt) + e.call(nil, n.Call) + } +} + +func (e *escape) stmts(l ir.Nodes) { + for _, n := range l { + e.stmt(n) + } +} + +// block is like stmts, but preserves loopDepth. +func (e *escape) block(l ir.Nodes) { + old := e.loopDepth + e.stmts(l) + e.loopDepth = old +} + +func (e *escape) dcl(n *ir.Name) hole { + if n.Curfn != e.curfn || n.IsClosureVar() { + base.Fatalf("bad declaration of %v", n) + } + loc := e.oldLoc(n) + loc.loopDepth = e.loopDepth + return loc.asHole() +} |