1 files changed, 411 insertions, 0 deletions
diff --git a/src/cmd/compile/internal/ir/stmt.go b/src/cmd/compile/internal/ir/stmt.go
new file mode 100644
index 0000000..80bd205
--- /dev/null
+++ b/src/cmd/compile/internal/ir/stmt.go
@@ -0,0 +1,411 @@
+// Copyright 2020 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 ir
+
+import (
+	"cmd/compile/internal/base"
+	"cmd/compile/internal/types"
+	"cmd/internal/src"
+)
+
+// A Decl is a declaration of a const, type, or var. (A declared func is a Func.)
+type Decl struct {
+	miniNode
+	X *Name // the thing being declared
+}
+
+func NewDecl(pos src.XPos, op Op, x *Name) *Decl {
+	n := &Decl{X: x}
+	n.pos = pos
+	switch op {
+	default:
+		panic("invalid Decl op " + op.String())
+	case ODCL, ODCLCONST, ODCLTYPE:
+		n.op = op
+	}
+	return n
+}
+
+func (*Decl) isStmt() {}
+
+// A Stmt is a Node that can appear as a statement.
+// This includes statement-like expressions such as f().
+//
+// (It's possible it should include <-c, but that would require
+// splitting ORECV out of UnaryExpr, which hasn't yet been
+// necessary. Maybe instead we will introduce ExprStmt at
+// some point.)
+type Stmt interface {
+	Node
+	isStmt()
+}
+
+// A miniStmt is a miniNode with extra fields common to statements.
+type miniStmt struct {
+	miniNode
+	init Nodes
+}
+
+func (*miniStmt) isStmt() {}
+
+func (n *miniStmt) Init() Nodes     { return n.init }
+func (n *miniStmt) SetInit(x Nodes) { n.init = x }
+func (n *miniStmt) PtrInit() *Nodes { return &n.init }
+
+// An AssignListStmt is an assignment statement with
+// more than one item on at least one side: Lhs = Rhs.
+// If Def is true, the assignment is a :=.
+type AssignListStmt struct {
+	miniStmt
+	Lhs Nodes
+	Def bool
+	Rhs Nodes
+}
+
+func NewAssignListStmt(pos src.XPos, op Op, lhs, rhs []Node) *AssignListStmt {
+	n := &AssignListStmt{}
+	n.pos = pos
+	n.SetOp(op)
+	n.Lhs = lhs
+	n.Rhs = rhs
+	return n
+}
+
+func (n *AssignListStmt) SetOp(op Op) {
+	switch op {
+	default:
+		panic(n.no("SetOp " + op.String()))
+	case OAS2, OAS2DOTTYPE, OAS2FUNC, OAS2MAPR, OAS2RECV, OSELRECV2:
+		n.op = op
+	}
+}
+
+// An AssignStmt is a simple assignment statement: X = Y.
+// If Def is true, the assignment is a :=.
+type AssignStmt struct {
+	miniStmt
+	X   Node
+	Def bool
+	Y   Node
+}
+
+func NewAssignStmt(pos src.XPos, x, y Node) *AssignStmt {
+	n := &AssignStmt{X: x, Y: y}
+	n.pos = pos
+	n.op = OAS
+	return n
+}
+
+func (n *AssignStmt) SetOp(op Op) {
+	switch op {
+	default:
+		panic(n.no("SetOp " + op.String()))
+	case OAS:
+		n.op = op
+	}
+}
+
+// An AssignOpStmt is an AsOp= assignment statement: X AsOp= Y.
+type AssignOpStmt struct {
+	miniStmt
+	X      Node
+	AsOp   Op // OADD etc
+	Y      Node
+	IncDec bool // actually ++ or --
+}
+
+func NewAssignOpStmt(pos src.XPos, asOp Op, x, y Node) *AssignOpStmt {
+	n := &AssignOpStmt{AsOp: asOp, X: x, Y: y}
+	n.pos = pos
+	n.op = OASOP
+	return n
+}
+
+// A BlockStmt is a block: { List }.
+type BlockStmt struct {
+	miniStmt
+	List Nodes
+}
+
+func NewBlockStmt(pos src.XPos, list []Node) *BlockStmt {
+	n := &BlockStmt{}
+	n.pos = pos
+	if !pos.IsKnown() {
+		n.pos = base.Pos
+		if len(list) > 0 {
+			n.pos = list[0].Pos()
+		}
+	}
+	n.op = OBLOCK
+	n.List = list
+	return n
+}
+
+// A BranchStmt is a break, continue, fallthrough, or goto statement.
+type BranchStmt struct {
+	miniStmt
+	Label *types.Sym // label if present
+}
+
+func NewBranchStmt(pos src.XPos, op Op, label *types.Sym) *BranchStmt {
+	switch op {
+	case OBREAK, OCONTINUE, OFALL, OGOTO:
+		// ok
+	default:
+		panic("NewBranch " + op.String())
+	}
+	n := &BranchStmt{Label: label}
+	n.pos = pos
+	n.op = op
+	return n
+}
+
+func (n *BranchStmt) Sym() *types.Sym { return n.Label }
+
+// A CaseClause is a case statement in a switch or select: case List: Body.
+type CaseClause struct {
+	miniStmt
+	Var  *Name // declared variable for this case in type switch
+	List Nodes // list of expressions for switch, early select
+	Body Nodes
+}
+
+func NewCaseStmt(pos src.XPos, list, body []Node) *CaseClause {
+	n := &CaseClause{List: list, Body: body}
+	n.pos = pos
+	n.op = OCASE
+	return n
+}
+
+type CommClause struct {
+	miniStmt
+	Comm Node // communication case
+	Body Nodes
+}
+
+func NewCommStmt(pos src.XPos, comm Node, body []Node) *CommClause {
+	n := &CommClause{Comm: comm, Body: body}
+	n.pos = pos
+	n.op = OCASE
+	return n
+}
+
+// A ForStmt is a non-range for loop: for Init; Cond; Post { Body }
+// Op can be OFOR or OFORUNTIL (!Cond).
+type ForStmt struct {
+	miniStmt
+	Label    *types.Sym
+	Cond     Node
+	Late     Nodes
+	Post     Node
+	Body     Nodes
+	HasBreak bool
+}
+
+func NewForStmt(pos src.XPos, init Node, cond, post Node, body []Node) *ForStmt {
+	n := &ForStmt{Cond: cond, Post: post}
+	n.pos = pos
+	n.op = OFOR
+	if init != nil {
+		n.init = []Node{init}
+	}
+	n.Body = body
+	return n
+}
+
+func (n *ForStmt) SetOp(op Op) {
+	if op != OFOR && op != OFORUNTIL {
+		panic(n.no("SetOp " + op.String()))
+	}
+	n.op = op
+}
+
+// A GoDeferStmt is a go or defer statement: go Call / defer Call.
+//
+// The two opcodes use a single syntax because the implementations
+// are very similar: both are concerned with saving Call and running it
+// in a different context (a separate goroutine or a later time).
+type GoDeferStmt struct {
+	miniStmt
+	Call Node
+}
+
+func NewGoDeferStmt(pos src.XPos, op Op, call Node) *GoDeferStmt {
+	n := &GoDeferStmt{Call: call}
+	n.pos = pos
+	switch op {
+	case ODEFER, OGO:
+		n.op = op
+	default:
+		panic("NewGoDeferStmt " + op.String())
+	}
+	return n
+}
+
+// An IfStmt is a return statement: if Init; Cond { Body } else { Else }.
+type IfStmt struct {
+	miniStmt
+	Cond   Node
+	Body   Nodes
+	Else   Nodes
+	Likely bool // code layout hint
+}
+
+func NewIfStmt(pos src.XPos, cond Node, body, els []Node) *IfStmt {
+	n := &IfStmt{Cond: cond}
+	n.pos = pos
+	n.op = OIF
+	n.Body = body
+	n.Else = els
+	return n
+}
+
+// An InlineMarkStmt is a marker placed just before an inlined body.
+type InlineMarkStmt struct {
+	miniStmt
+	Index int64
+}
+
+func NewInlineMarkStmt(pos src.XPos, index int64) *InlineMarkStmt {
+	n := &InlineMarkStmt{Index: index}
+	n.pos = pos
+	n.op = OINLMARK
+	return n
+}
+
+func (n *InlineMarkStmt) Offset() int64     { return n.Index }
+func (n *InlineMarkStmt) SetOffset(x int64) { n.Index = x }
+
+// A LabelStmt is a label statement (just the label, not including the statement it labels).
+type LabelStmt struct {
+	miniStmt
+	Label *types.Sym // "Label:"
+}
+
+func NewLabelStmt(pos src.XPos, label *types.Sym) *LabelStmt {
+	n := &LabelStmt{Label: label}
+	n.pos = pos
+	n.op = OLABEL
+	return n
+}
+
+func (n *LabelStmt) Sym() *types.Sym { return n.Label }
+
+// A RangeStmt is a range loop: for Key, Value = range X { Body }
+type RangeStmt struct {
+	miniStmt
+	Label    *types.Sym
+	Def      bool
+	X        Node
+	Key      Node
+	Value    Node
+	Body     Nodes
+	HasBreak bool
+	Prealloc *Name
+}
+
+func NewRangeStmt(pos src.XPos, key, value, x Node, body []Node) *RangeStmt {
+	n := &RangeStmt{X: x, Key: key, Value: value}
+	n.pos = pos
+	n.op = ORANGE
+	n.Body = body
+	return n
+}
+
+// A ReturnStmt is a return statement.
+type ReturnStmt struct {
+	miniStmt
+	origNode       // for typecheckargs rewrite
+	Results  Nodes // return list
+}
+
+func NewReturnStmt(pos src.XPos, results []Node) *ReturnStmt {
+	n := &ReturnStmt{}
+	n.pos = pos
+	n.op = ORETURN
+	n.orig = n
+	n.Results = results
+	return n
+}
+
+// A SelectStmt is a block: { Cases }.
+type SelectStmt struct {
+	miniStmt
+	Label    *types.Sym
+	Cases    []*CommClause
+	HasBreak bool
+
+	// TODO(rsc): Instead of recording here, replace with a block?
+	Compiled Nodes // compiled form, after walkSelect
+}
+
+func NewSelectStmt(pos src.XPos, cases []*CommClause) *SelectStmt {
+	n := &SelectStmt{Cases: cases}
+	n.pos = pos
+	n.op = OSELECT
+	return n
+}
+
+// A SendStmt is a send statement: X <- Y.
+type SendStmt struct {
+	miniStmt
+	Chan  Node
+	Value Node
+}
+
+func NewSendStmt(pos src.XPos, ch, value Node) *SendStmt {
+	n := &SendStmt{Chan: ch, Value: value}
+	n.pos = pos
+	n.op = OSEND
+	return n
+}
+
+// A SwitchStmt is a switch statement: switch Init; Tag { Cases }.
+type SwitchStmt struct {
+	miniStmt
+	Tag      Node
+	Cases    []*CaseClause
+	Label    *types.Sym
+	HasBreak bool
+
+	// TODO(rsc): Instead of recording here, replace with a block?
+	Compiled Nodes // compiled form, after walkSwitch
+}
+
+func NewSwitchStmt(pos src.XPos, tag Node, cases []*CaseClause) *SwitchStmt {
+	n := &SwitchStmt{Tag: tag, Cases: cases}
+	n.pos = pos
+	n.op = OSWITCH
+	return n
+}
+
+// A TailCallStmt is a tail call statement, which is used for back-end
+// code generation to jump directly to another function entirely.
+type TailCallStmt struct {
+	miniStmt
+	Call *CallExpr // the underlying call
+}
+
+func NewTailCallStmt(pos src.XPos, call *CallExpr) *TailCallStmt {
+	n := &TailCallStmt{Call: call}
+	n.pos = pos
+	n.op = OTAILCALL
+	return n
+}
+
+// A TypeSwitchGuard is the [Name :=] X.(type) in a type switch.
+type TypeSwitchGuard struct {
+	miniNode
+	Tag  *Ident
+	X    Node
+	Used bool
+}
+
+func NewTypeSwitchGuard(pos src.XPos, tag *Ident, x Node) *TypeSwitchGuard {
+	n := &TypeSwitchGuard{Tag: tag, X: x}
+	n.pos = pos
+	n.op = OTYPESW
+	return n
+}