diff options
Diffstat (limited to 'src/cmd/compile/internal/ir/node.go')
| -rw-r--r-- | src/cmd/compile/internal/ir/node.go | 597 |
1 files changed, 597 insertions, 0 deletions
diff --git a/src/cmd/compile/internal/ir/node.go b/src/cmd/compile/internal/ir/node.go new file mode 100644 index 0000000..547dd48 --- /dev/null +++ b/src/cmd/compile/internal/ir/node.go @@ -0,0 +1,597 @@ +// Copyright 2009 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. + +// “Abstract” syntax representation. + +package ir + +import ( + "fmt" + "go/constant" + "sort" + + "cmd/compile/internal/base" + "cmd/compile/internal/types" + "cmd/internal/src" +) + +// A Node is the abstract interface to an IR node. +type Node interface { + // Formatting + Format(s fmt.State, verb rune) + + // Source position. + Pos() src.XPos + SetPos(x src.XPos) + + // For making copies. For Copy and SepCopy. + copy() Node + + doChildren(func(Node) bool) bool + editChildren(func(Node) Node) + editChildrenWithHidden(func(Node) Node) + + // Abstract graph structure, for generic traversals. + Op() Op + Init() Nodes + + // Fields specific to certain Ops only. + Type() *types.Type + SetType(t *types.Type) + Name() *Name + Sym() *types.Sym + Val() constant.Value + SetVal(v constant.Value) + + // Storage for analysis passes. + Esc() uint16 + SetEsc(x uint16) + + // Typecheck values: + // 0 means the node is not typechecked + // 1 means the node is completely typechecked + // 2 means typechecking of the node is in progress + // 3 means the node has its type from types2, but may need transformation + Typecheck() uint8 + SetTypecheck(x uint8) + NonNil() bool + MarkNonNil() +} + +// Line returns n's position as a string. If n has been inlined, +// it uses the outermost position where n has been inlined. +func Line(n Node) string { + return base.FmtPos(n.Pos()) +} + +func IsSynthetic(n Node) bool { + name := n.Sym().Name + return name[0] == '.' || name[0] == '~' +} + +// IsAutoTmp indicates if n was created by the compiler as a temporary, +// based on the setting of the .AutoTemp flag in n's Name. +func IsAutoTmp(n Node) bool { + if n == nil || n.Op() != ONAME { + return false + } + return n.Name().AutoTemp() +} + +// MayBeShared reports whether n may occur in multiple places in the AST. +// Extra care must be taken when mutating such a node. +func MayBeShared(n Node) bool { + switch n.Op() { + case ONAME, OLITERAL, ONIL, OTYPE: + return true + } + return false +} + +type InitNode interface { + Node + PtrInit() *Nodes + SetInit(x Nodes) +} + +func TakeInit(n Node) Nodes { + init := n.Init() + if len(init) != 0 { + n.(InitNode).SetInit(nil) + } + return init +} + +//go:generate stringer -type=Op -trimprefix=O node.go + +type Op uint8 + +// Node ops. +const ( + OXXX Op = iota + + // names + ONAME // var or func name + // Unnamed arg or return value: f(int, string) (int, error) { etc } + // Also used for a qualified package identifier that hasn't been resolved yet. + ONONAME + OTYPE // type name + OLITERAL // literal + ONIL // nil + + // expressions + OADD // X + Y + OSUB // X - Y + OOR // X | Y + OXOR // X ^ Y + OADDSTR // +{List} (string addition, list elements are strings) + OADDR // &X + OANDAND // X && Y + OAPPEND // append(Args); after walk, X may contain elem type descriptor + OBYTES2STR // Type(X) (Type is string, X is a []byte) + OBYTES2STRTMP // Type(X) (Type is string, X is a []byte, ephemeral) + ORUNES2STR // Type(X) (Type is string, X is a []rune) + OSTR2BYTES // Type(X) (Type is []byte, X is a string) + OSTR2BYTESTMP // Type(X) (Type is []byte, X is a string, ephemeral) + OSTR2RUNES // Type(X) (Type is []rune, X is a string) + OSLICE2ARR // Type(X) (Type is [N]T, X is a []T) + OSLICE2ARRPTR // Type(X) (Type is *[N]T, X is a []T) + // X = Y or (if Def=true) X := Y + // If Def, then Init includes a DCL node for X. + OAS + // Lhs = Rhs (x, y, z = a, b, c) or (if Def=true) Lhs := Rhs + // If Def, then Init includes DCL nodes for Lhs + OAS2 + OAS2DOTTYPE // Lhs = Rhs (x, ok = I.(int)) + OAS2FUNC // Lhs = Rhs (x, y = f()) + OAS2MAPR // Lhs = Rhs (x, ok = m["foo"]) + OAS2RECV // Lhs = Rhs (x, ok = <-c) + OASOP // X AsOp= Y (x += y) + OCALL // X(Args) (function call, method call or type conversion) + + // OCALLFUNC, OCALLMETH, and OCALLINTER have the same structure. + // Prior to walk, they are: X(Args), where Args is all regular arguments. + // After walk, if any argument whose evaluation might requires temporary variable, + // that temporary variable will be pushed to Init, Args will contains an updated + // set of arguments. + OCALLFUNC // X(Args) (function call f(args)) + OCALLMETH // X(Args) (direct method call x.Method(args)) + OCALLINTER // X(Args) (interface method call x.Method(args)) + OCAP // cap(X) + OCLOSE // close(X) + OCLOSURE // func Type { Func.Closure.Body } (func literal) + OCOMPLIT // Type{List} (composite literal, not yet lowered to specific form) + OMAPLIT // Type{List} (composite literal, Type is map) + OSTRUCTLIT // Type{List} (composite literal, Type is struct) + OARRAYLIT // Type{List} (composite literal, Type is array) + OSLICELIT // Type{List} (composite literal, Type is slice), Len is slice length. + OPTRLIT // &X (X is composite literal) + OCONV // Type(X) (type conversion) + OCONVIFACE // Type(X) (type conversion, to interface) + OCONVIDATA // Builds a data word to store X in an interface. Equivalent to IDATA(CONVIFACE(X)). Is an ir.ConvExpr. + OCONVNOP // Type(X) (type conversion, no effect) + OCOPY // copy(X, Y) + ODCL // var X (declares X of type X.Type) + + // Used during parsing but don't last. + ODCLFUNC // func f() or func (r) f() + ODCLCONST // const pi = 3.14 + ODCLTYPE // type Int int or type Int = int + + ODELETE // delete(Args) + ODOT // X.Sel (X is of struct type) + ODOTPTR // X.Sel (X is of pointer to struct type) + ODOTMETH // X.Sel (X is non-interface, Sel is method name) + ODOTINTER // X.Sel (X is interface, Sel is method name) + OXDOT // X.Sel (before rewrite to one of the preceding) + ODOTTYPE // X.Ntype or X.Type (.Ntype during parsing, .Type once resolved); after walk, Itab contains address of interface type descriptor and Itab.X contains address of concrete type descriptor + ODOTTYPE2 // X.Ntype or X.Type (.Ntype during parsing, .Type once resolved; on rhs of OAS2DOTTYPE); after walk, Itab contains address of interface type descriptor + OEQ // X == Y + ONE // X != Y + OLT // X < Y + OLE // X <= Y + OGE // X >= Y + OGT // X > Y + ODEREF // *X + OINDEX // X[Index] (index of array or slice) + OINDEXMAP // X[Index] (index of map) + OKEY // Key:Value (key:value in struct/array/map literal) + OSTRUCTKEY // Field:Value (key:value in struct literal, after type checking) + OLEN // len(X) + OMAKE // make(Args) (before type checking converts to one of the following) + OMAKECHAN // make(Type[, Len]) (type is chan) + OMAKEMAP // make(Type[, Len]) (type is map) + OMAKESLICE // make(Type[, Len[, Cap]]) (type is slice) + OMAKESLICECOPY // makeslicecopy(Type, Len, Cap) (type is slice; Len is length and Cap is the copied from slice) + // OMAKESLICECOPY is created by the order pass and corresponds to: + // s = make(Type, Len); copy(s, Cap) + // + // Bounded can be set on the node when Len == len(Cap) is known at compile time. + // + // This node is created so the walk pass can optimize this pattern which would + // otherwise be hard to detect after the order pass. + OMUL // X * Y + ODIV // X / Y + OMOD // X % Y + OLSH // X << Y + ORSH // X >> Y + OAND // X & Y + OANDNOT // X &^ Y + ONEW // new(X); corresponds to calls to new in source code + ONOT // !X + OBITNOT // ^X + OPLUS // +X + ONEG // -X + OOROR // X || Y + OPANIC // panic(X) + OPRINT // print(List) + OPRINTN // println(List) + OPAREN // (X) + OSEND // Chan <- Value + OSLICE // X[Low : High] (X is untypechecked or slice) + OSLICEARR // X[Low : High] (X is pointer to array) + OSLICESTR // X[Low : High] (X is string) + OSLICE3 // X[Low : High : Max] (X is untypedchecked or slice) + OSLICE3ARR // X[Low : High : Max] (X is pointer to array) + OSLICEHEADER // sliceheader{Ptr, Len, Cap} (Ptr is unsafe.Pointer, Len is length, Cap is capacity) + OSTRINGHEADER // stringheader{Ptr, Len} (Ptr is unsafe.Pointer, Len is length) + ORECOVER // recover() + ORECOVERFP // recover(Args) w/ explicit FP argument + ORECV // <-X + ORUNESTR // Type(X) (Type is string, X is rune) + OSELRECV2 // like OAS2: Lhs = Rhs where len(Lhs)=2, len(Rhs)=1, Rhs[0].Op = ORECV (appears as .Var of OCASE) + OREAL // real(X) + OIMAG // imag(X) + OCOMPLEX // complex(X, Y) + OALIGNOF // unsafe.Alignof(X) + OOFFSETOF // unsafe.Offsetof(X) + OSIZEOF // unsafe.Sizeof(X) + OUNSAFEADD // unsafe.Add(X, Y) + OUNSAFESLICE // unsafe.Slice(X, Y) + OUNSAFESLICEDATA // unsafe.SliceData(X) + OUNSAFESTRING // unsafe.String(X, Y) + OUNSAFESTRINGDATA // unsafe.StringData(X) + OMETHEXPR // X(Args) (method expression T.Method(args), first argument is the method receiver) + OMETHVALUE // X.Sel (method expression t.Method, not called) + + // statements + OBLOCK // { List } (block of code) + OBREAK // break [Label] + // OCASE: case List: Body (List==nil means default) + // For OTYPESW, List is a OTYPE node for the specified type (or OLITERAL + // for nil) or an ODYNAMICTYPE indicating a runtime type for generics. + // If a type-switch variable is specified, Var is an + // ONAME for the version of the type-switch variable with the specified + // type. + OCASE + OCONTINUE // continue [Label] + ODEFER // defer Call + OFALL // fallthrough + OFOR // for Init; Cond; Post { Body } + OGOTO // goto Label + OIF // if Init; Cond { Then } else { Else } + OLABEL // Label: + OGO // go Call + ORANGE // for Key, Value = range X { Body } + ORETURN // return Results + OSELECT // select { Cases } + OSWITCH // switch Init; Expr { Cases } + // OTYPESW: X := Y.(type) (appears as .Tag of OSWITCH) + // X is nil if there is no type-switch variable + OTYPESW + OFUNCINST // instantiation of a generic function + + // misc + // intermediate representation of an inlined call. Uses Init (assignments + // for the captured variables, parameters, retvars, & INLMARK op), + // Body (body of the inlined function), and ReturnVars (list of + // return values) + OINLCALL // intermediary representation of an inlined call. + OEFACE // itable and data words of an empty-interface value. + OITAB // itable word of an interface value. + OIDATA // data word of an interface value in X + OSPTR // base pointer of a slice or string. Bounded==1 means known non-nil. + OCFUNC // reference to c function pointer (not go func value) + OCHECKNIL // emit code to ensure pointer/interface not nil + ORESULT // result of a function call; Xoffset is stack offset + OINLMARK // start of an inlined body, with file/line of caller. Xoffset is an index into the inline tree. + OLINKSYMOFFSET // offset within a name + OJUMPTABLE // A jump table structure for implementing dense expression switches + + // opcodes for generics + ODYNAMICDOTTYPE // x = i.(T) where T is a type parameter (or derived from a type parameter) + ODYNAMICDOTTYPE2 // x, ok = i.(T) where T is a type parameter (or derived from a type parameter) + ODYNAMICTYPE // a type node for type switches (represents a dynamic target type for a type switch) + + // arch-specific opcodes + OTAILCALL // tail call to another function + OGETG // runtime.getg() (read g pointer) + OGETCALLERPC // runtime.getcallerpc() (continuation PC in caller frame) + OGETCALLERSP // runtime.getcallersp() (stack pointer in caller frame) + + OEND +) + +// IsCmp reports whether op is a comparison operation (==, !=, <, <=, +// >, or >=). +func (op Op) IsCmp() bool { + switch op { + case OEQ, ONE, OLT, OLE, OGT, OGE: + return true + } + return false +} + +// Nodes is a pointer to a slice of *Node. +// For fields that are not used in most nodes, this is used instead of +// a slice to save space. +type Nodes []Node + +// Append appends entries to Nodes. +func (n *Nodes) Append(a ...Node) { + if len(a) == 0 { + return + } + *n = append(*n, a...) +} + +// Prepend prepends entries to Nodes. +// If a slice is passed in, this will take ownership of it. +func (n *Nodes) Prepend(a ...Node) { + if len(a) == 0 { + return + } + *n = append(a, *n...) +} + +// Take clears n, returning its former contents. +func (n *Nodes) Take() []Node { + ret := *n + *n = nil + return ret +} + +// Copy returns a copy of the content of the slice. +func (n Nodes) Copy() Nodes { + if n == nil { + return nil + } + c := make(Nodes, len(n)) + copy(c, n) + return c +} + +// NameQueue is a FIFO queue of *Name. The zero value of NameQueue is +// a ready-to-use empty queue. +type NameQueue struct { + ring []*Name + head, tail int +} + +// Empty reports whether q contains no Names. +func (q *NameQueue) Empty() bool { + return q.head == q.tail +} + +// PushRight appends n to the right of the queue. +func (q *NameQueue) PushRight(n *Name) { + if len(q.ring) == 0 { + q.ring = make([]*Name, 16) + } else if q.head+len(q.ring) == q.tail { + // Grow the ring. + nring := make([]*Name, len(q.ring)*2) + // Copy the old elements. + part := q.ring[q.head%len(q.ring):] + if q.tail-q.head <= len(part) { + part = part[:q.tail-q.head] + copy(nring, part) + } else { + pos := copy(nring, part) + copy(nring[pos:], q.ring[:q.tail%len(q.ring)]) + } + q.ring, q.head, q.tail = nring, 0, q.tail-q.head + } + + q.ring[q.tail%len(q.ring)] = n + q.tail++ +} + +// PopLeft pops a Name from the left of the queue. It panics if q is +// empty. +func (q *NameQueue) PopLeft() *Name { + if q.Empty() { + panic("dequeue empty") + } + n := q.ring[q.head%len(q.ring)] + q.head++ + return n +} + +// NameSet is a set of Names. +type NameSet map[*Name]struct{} + +// Has reports whether s contains n. +func (s NameSet) Has(n *Name) bool { + _, isPresent := s[n] + return isPresent +} + +// Add adds n to s. +func (s *NameSet) Add(n *Name) { + if *s == nil { + *s = make(map[*Name]struct{}) + } + (*s)[n] = struct{}{} +} + +// Sorted returns s sorted according to less. +func (s NameSet) Sorted(less func(*Name, *Name) bool) []*Name { + var res []*Name + for n := range s { + res = append(res, n) + } + sort.Slice(res, func(i, j int) bool { return less(res[i], res[j]) }) + return res +} + +type PragmaFlag uint16 + +const ( + // Func pragmas. + Nointerface PragmaFlag = 1 << iota + Noescape // func parameters don't escape + Norace // func must not have race detector annotations + Nosplit // func should not execute on separate stack + Noinline // func should not be inlined + NoCheckPtr // func should not be instrumented by checkptr + CgoUnsafeArgs // treat a pointer to one arg as a pointer to them all + UintptrKeepAlive // pointers converted to uintptr must be kept alive + UintptrEscapes // pointers converted to uintptr escape + + // Runtime-only func pragmas. + // See ../../../../runtime/HACKING.md for detailed descriptions. + Systemstack // func must run on system stack + Nowritebarrier // emit compiler error instead of write barrier + Nowritebarrierrec // error on write barrier in this or recursive callees + Yeswritebarrierrec // cancels Nowritebarrierrec in this function and callees + + // Go command pragmas + GoBuildPragma + + RegisterParams // TODO(register args) remove after register abi is working + +) + +func AsNode(n types.Object) Node { + if n == nil { + return nil + } + return n.(Node) +} + +var BlankNode Node + +func IsConst(n Node, ct constant.Kind) bool { + return ConstType(n) == ct +} + +// IsNil reports whether n represents the universal untyped zero value "nil". +func IsNil(n Node) bool { + // Check n.Orig because constant propagation may produce typed nil constants, + // which don't exist in the Go spec. + return n != nil && Orig(n).Op() == ONIL +} + +func IsBlank(n Node) bool { + if n == nil { + return false + } + return n.Sym().IsBlank() +} + +// IsMethod reports whether n is a method. +// n must be a function or a method. +func IsMethod(n Node) bool { + return n.Type().Recv() != nil +} + +func HasNamedResults(fn *Func) bool { + typ := fn.Type() + return typ.NumResults() > 0 && types.OrigSym(typ.Results().Field(0).Sym) != nil +} + +// HasUniquePos reports whether n has a unique position that can be +// used for reporting error messages. +// +// It's primarily used to distinguish references to named objects, +// whose Pos will point back to their declaration position rather than +// their usage position. +func HasUniquePos(n Node) bool { + switch n.Op() { + case ONAME: + return false + case OLITERAL, ONIL, OTYPE: + if n.Sym() != nil { + return false + } + } + + if !n.Pos().IsKnown() { + if base.Flag.K != 0 { + base.Warn("setlineno: unknown position (line 0)") + } + return false + } + + return true +} + +func SetPos(n Node) src.XPos { + lno := base.Pos + if n != nil && HasUniquePos(n) { + base.Pos = n.Pos() + } + return lno +} + +// The result of InitExpr MUST be assigned back to n, e.g. +// +// n.X = InitExpr(init, n.X) +func InitExpr(init []Node, expr Node) Node { + if len(init) == 0 { + return expr + } + + n, ok := expr.(InitNode) + if !ok || MayBeShared(n) { + // Introduce OCONVNOP to hold init list. + n = NewConvExpr(base.Pos, OCONVNOP, nil, expr) + n.SetType(expr.Type()) + n.SetTypecheck(1) + } + + n.PtrInit().Prepend(init...) + return n +} + +// what's the outer value that a write to n affects? +// outer value means containing struct or array. +func OuterValue(n Node) Node { + for { + switch nn := n; nn.Op() { + case OXDOT: + base.FatalfAt(n.Pos(), "OXDOT in OuterValue: %v", n) + case ODOT: + nn := nn.(*SelectorExpr) + n = nn.X + continue + case OPAREN: + nn := nn.(*ParenExpr) + n = nn.X + continue + case OCONVNOP: + nn := nn.(*ConvExpr) + n = nn.X + continue + case OINDEX: + nn := nn.(*IndexExpr) + if nn.X.Type() == nil { + base.Fatalf("OuterValue needs type for %v", nn.X) + } + if nn.X.Type().IsArray() { + n = nn.X + continue + } + } + + return n + } +} + +const ( + EscUnknown = iota + EscNone // Does not escape to heap, result, or parameters. + EscHeap // Reachable from the heap + EscNever // By construction will not escape. +) |