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// 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/obj"
"cmd/internal/objabi"
"cmd/internal/src"
"fmt"
"go/constant"
)
// An Ident is an identifier, possibly qualified.
type Ident struct {
miniExpr
sym *types.Sym
}
func NewIdent(pos src.XPos, sym *types.Sym) *Ident {
n := new(Ident)
n.op = ONONAME
n.pos = pos
n.sym = sym
return n
}
func (n *Ident) Sym() *types.Sym { return n.sym }
// Name holds Node fields used only by named nodes (ONAME, OTYPE, some OLITERAL).
type Name struct {
miniExpr
BuiltinOp Op // uint8
Class Class // uint8
pragma PragmaFlag // int16
flags bitset16
DictIndex uint16 // index of the dictionary entry describing the type of this variable declaration plus 1
sym *types.Sym
Func *Func // TODO(austin): nil for I.M
Offset_ int64
val constant.Value
Opt interface{} // for use by escape analysis
Embed *[]Embed // list of embedded files, for ONAME var
// For a local variable (not param) or extern, the initializing assignment (OAS or OAS2).
// For a closure var, the ONAME node of the original (outermost) captured variable.
// For the case-local variables of a type switch, the type switch guard (OTYPESW).
// For a range variable, the range statement (ORANGE)
// For a recv variable in a case of a select statement, the receive assignment (OSELRECV2)
// For the name of a function, points to corresponding Func node.
Defn Node
// The function, method, or closure in which local variable or param is declared.
Curfn *Func
Heapaddr *Name // temp holding heap address of param
// Outer points to the immediately enclosing function's copy of this
// closure variable. If not a closure variable, then Outer is nil.
Outer *Name
}
func (n *Name) isExpr() {}
func (n *Name) copy() Node { panic(n.no("copy")) }
func (n *Name) doChildren(do func(Node) bool) bool { return false }
func (n *Name) editChildren(edit func(Node) Node) {}
func (n *Name) editChildrenWithHidden(edit func(Node) Node) {}
// RecordFrameOffset records the frame offset for the name.
// It is used by package types when laying out function arguments.
func (n *Name) RecordFrameOffset(offset int64) {
n.SetFrameOffset(offset)
}
// NewNameAt returns a new ONAME Node associated with symbol s at position pos.
// The caller is responsible for setting Curfn.
func NewNameAt(pos src.XPos, sym *types.Sym, typ *types.Type) *Name {
if sym == nil {
base.Fatalf("NewNameAt nil")
}
n := newNameAt(pos, ONAME, sym)
if typ != nil {
n.SetType(typ)
n.SetTypecheck(1)
}
return n
}
// NewBuiltin returns a new Name representing a builtin function,
// either predeclared or from package unsafe.
func NewBuiltin(sym *types.Sym, op Op) *Name {
n := newNameAt(src.NoXPos, ONAME, sym)
n.BuiltinOp = op
n.SetTypecheck(1)
sym.Def = n
return n
}
// NewLocal returns a new function-local variable with the given name and type.
func (fn *Func) NewLocal(pos src.XPos, sym *types.Sym, typ *types.Type) *Name {
if fn.Dcl == nil {
base.FatalfAt(pos, "must call DeclParams on %v first", fn)
}
n := NewNameAt(pos, sym, typ)
n.Class = PAUTO
n.Curfn = fn
fn.Dcl = append(fn.Dcl, n)
return n
}
// NewDeclNameAt returns a new Name associated with symbol s at position pos.
// The caller is responsible for setting Curfn.
func NewDeclNameAt(pos src.XPos, op Op, sym *types.Sym) *Name {
if sym == nil {
base.Fatalf("NewDeclNameAt nil")
}
switch op {
case ONAME, OTYPE, OLITERAL:
// ok
default:
base.Fatalf("NewDeclNameAt op %v", op)
}
return newNameAt(pos, op, sym)
}
// NewConstAt returns a new OLITERAL Node associated with symbol s at position pos.
func NewConstAt(pos src.XPos, sym *types.Sym, typ *types.Type, val constant.Value) *Name {
if sym == nil {
base.Fatalf("NewConstAt nil")
}
n := newNameAt(pos, OLITERAL, sym)
n.SetType(typ)
n.SetTypecheck(1)
n.SetVal(val)
return n
}
// newNameAt is like NewNameAt but allows sym == nil.
func newNameAt(pos src.XPos, op Op, sym *types.Sym) *Name {
n := new(Name)
n.op = op
n.pos = pos
n.sym = sym
return n
}
func (n *Name) Name() *Name { return n }
func (n *Name) Sym() *types.Sym { return n.sym }
func (n *Name) SetSym(x *types.Sym) { n.sym = x }
func (n *Name) SubOp() Op { return n.BuiltinOp }
func (n *Name) SetSubOp(x Op) { n.BuiltinOp = x }
func (n *Name) SetFunc(x *Func) { n.Func = x }
func (n *Name) FrameOffset() int64 { return n.Offset_ }
func (n *Name) SetFrameOffset(x int64) { n.Offset_ = x }
func (n *Name) Linksym() *obj.LSym { return n.sym.Linksym() }
func (n *Name) LinksymABI(abi obj.ABI) *obj.LSym { return n.sym.LinksymABI(abi) }
func (*Name) CanBeNtype() {}
func (*Name) CanBeAnSSASym() {}
func (*Name) CanBeAnSSAAux() {}
// Pragma returns the PragmaFlag for p, which must be for an OTYPE.
func (n *Name) Pragma() PragmaFlag { return n.pragma }
// SetPragma sets the PragmaFlag for p, which must be for an OTYPE.
func (n *Name) SetPragma(flag PragmaFlag) { n.pragma = flag }
// Alias reports whether p, which must be for an OTYPE, is a type alias.
func (n *Name) Alias() bool { return n.flags&nameAlias != 0 }
// SetAlias sets whether p, which must be for an OTYPE, is a type alias.
func (n *Name) SetAlias(alias bool) { n.flags.set(nameAlias, alias) }
const (
nameReadonly = 1 << iota
nameByval // is the variable captured by value or by reference
nameNeedzero // if it contains pointers, needs to be zeroed on function entry
nameAutoTemp // is the variable a temporary (implies no dwarf info. reset if escapes to heap)
nameUsed // for variable declared and not used error
nameIsClosureVar // PAUTOHEAP closure pseudo-variable; original (if any) at n.Defn
nameIsOutputParamHeapAddr // pointer to a result parameter's heap copy
nameIsOutputParamInRegisters // output parameter in registers spills as an auto
nameAddrtaken // address taken, even if not moved to heap
nameInlFormal // PAUTO created by inliner, derived from callee formal
nameInlLocal // PAUTO created by inliner, derived from callee local
nameOpenDeferSlot // if temporary var storing info for open-coded defers
nameLibfuzzer8BitCounter // if PEXTERN should be assigned to __sancov_cntrs section
nameCoverageAuxVar // instrumentation counter var or pkg ID for cmd/cover
nameAlias // is type name an alias
)
func (n *Name) Readonly() bool { return n.flags&nameReadonly != 0 }
func (n *Name) Needzero() bool { return n.flags&nameNeedzero != 0 }
func (n *Name) AutoTemp() bool { return n.flags&nameAutoTemp != 0 }
func (n *Name) Used() bool { return n.flags&nameUsed != 0 }
func (n *Name) IsClosureVar() bool { return n.flags&nameIsClosureVar != 0 }
func (n *Name) IsOutputParamHeapAddr() bool { return n.flags&nameIsOutputParamHeapAddr != 0 }
func (n *Name) IsOutputParamInRegisters() bool { return n.flags&nameIsOutputParamInRegisters != 0 }
func (n *Name) Addrtaken() bool { return n.flags&nameAddrtaken != 0 }
func (n *Name) InlFormal() bool { return n.flags&nameInlFormal != 0 }
func (n *Name) InlLocal() bool { return n.flags&nameInlLocal != 0 }
func (n *Name) OpenDeferSlot() bool { return n.flags&nameOpenDeferSlot != 0 }
func (n *Name) Libfuzzer8BitCounter() bool { return n.flags&nameLibfuzzer8BitCounter != 0 }
func (n *Name) CoverageAuxVar() bool { return n.flags&nameCoverageAuxVar != 0 }
func (n *Name) setReadonly(b bool) { n.flags.set(nameReadonly, b) }
func (n *Name) SetNeedzero(b bool) { n.flags.set(nameNeedzero, b) }
func (n *Name) SetAutoTemp(b bool) { n.flags.set(nameAutoTemp, b) }
func (n *Name) SetUsed(b bool) { n.flags.set(nameUsed, b) }
func (n *Name) SetIsClosureVar(b bool) { n.flags.set(nameIsClosureVar, b) }
func (n *Name) SetIsOutputParamHeapAddr(b bool) { n.flags.set(nameIsOutputParamHeapAddr, b) }
func (n *Name) SetIsOutputParamInRegisters(b bool) { n.flags.set(nameIsOutputParamInRegisters, b) }
func (n *Name) SetAddrtaken(b bool) { n.flags.set(nameAddrtaken, b) }
func (n *Name) SetInlFormal(b bool) { n.flags.set(nameInlFormal, b) }
func (n *Name) SetInlLocal(b bool) { n.flags.set(nameInlLocal, b) }
func (n *Name) SetOpenDeferSlot(b bool) { n.flags.set(nameOpenDeferSlot, b) }
func (n *Name) SetLibfuzzer8BitCounter(b bool) { n.flags.set(nameLibfuzzer8BitCounter, b) }
func (n *Name) SetCoverageAuxVar(b bool) { n.flags.set(nameCoverageAuxVar, b) }
// OnStack reports whether variable n may reside on the stack.
func (n *Name) OnStack() bool {
if n.Op() == ONAME {
switch n.Class {
case PPARAM, PPARAMOUT, PAUTO:
return n.Esc() != EscHeap
case PEXTERN, PAUTOHEAP:
return false
}
}
// Note: fmt.go:dumpNodeHeader calls all "func() bool"-typed
// methods, but it can only recover from panics, not Fatalf.
panic(fmt.Sprintf("%v: not a variable: %v", base.FmtPos(n.Pos()), n))
}
// MarkReadonly indicates that n is an ONAME with readonly contents.
func (n *Name) MarkReadonly() {
if n.Op() != ONAME {
base.Fatalf("Node.MarkReadonly %v", n.Op())
}
n.setReadonly(true)
// Mark the linksym as readonly immediately
// so that the SSA backend can use this information.
// It will be overridden later during dumpglobls.
n.Linksym().Type = objabi.SRODATA
}
// Val returns the constant.Value for the node.
func (n *Name) Val() constant.Value {
if n.val == nil {
return constant.MakeUnknown()
}
return n.val
}
// SetVal sets the constant.Value for the node.
func (n *Name) SetVal(v constant.Value) {
if n.op != OLITERAL {
panic(n.no("SetVal"))
}
AssertValidTypeForConst(n.Type(), v)
n.val = v
}
// Canonical returns the logical declaration that n represents. If n
// is a closure variable, then Canonical returns the original Name as
// it appears in the function that immediately contains the
// declaration. Otherwise, Canonical simply returns n itself.
func (n *Name) Canonical() *Name {
if n.IsClosureVar() && n.Defn != nil {
n = n.Defn.(*Name)
}
return n
}
func (n *Name) SetByval(b bool) {
if n.Canonical() != n {
base.Fatalf("SetByval called on non-canonical variable: %v", n)
}
n.flags.set(nameByval, b)
}
func (n *Name) Byval() bool {
// We require byval to be set on the canonical variable, but we
// allow it to be accessed from any instance.
return n.Canonical().flags&nameByval != 0
}
// NewClosureVar returns a new closure variable for fn to refer to
// outer variable n.
func NewClosureVar(pos src.XPos, fn *Func, n *Name) *Name {
switch n.Class {
case PAUTO, PPARAM, PPARAMOUT, PAUTOHEAP:
// ok
default:
// Prevent mistaken capture of global variables.
base.Fatalf("NewClosureVar: %+v", n)
}
c := NewNameAt(pos, n.Sym(), n.Type())
c.Curfn = fn
c.Class = PAUTOHEAP
c.SetIsClosureVar(true)
c.Defn = n.Canonical()
c.Outer = n
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, typ)
fake.Class = PPARAM
fake.SetByval(true)
return NewClosureVar(pos, fn, fake)
}
// SameSource reports whether two nodes refer to the same source
// element.
//
// It exists to help incrementally migrate the compiler towards
// allowing the introduction of IdentExpr (#42990). Once we have
// IdentExpr, it will no longer be safe to directly compare Node
// values to tell if they refer to the same Name. Instead, code will
// need to explicitly get references to the underlying Name object(s),
// and compare those instead.
//
// It will still be safe to compare Nodes directly for checking if two
// nodes are syntactically the same. The SameSource function exists to
// indicate code that intentionally compares Nodes for syntactic
// equality as opposed to code that has yet to be updated in
// preparation for IdentExpr.
func SameSource(n1, n2 Node) bool {
return n1 == n2
}
// Uses reports whether expression x is a (direct) use of the given
// variable.
func Uses(x Node, v *Name) bool {
if v == nil || v.Op() != ONAME {
base.Fatalf("RefersTo bad Name: %v", v)
}
return x.Op() == ONAME && x.Name() == v
}
// DeclaredBy reports whether expression x refers (directly) to a
// variable that was declared by the given statement.
func DeclaredBy(x, stmt Node) bool {
if stmt == nil {
base.Fatalf("DeclaredBy nil")
}
return x.Op() == ONAME && SameSource(x.Name().Defn, stmt)
}
// The Class of a variable/function describes the "storage class"
// of a variable or function. During parsing, storage classes are
// called declaration contexts.
type Class uint8
//go:generate stringer -type=Class name.go
const (
Pxxx Class = iota // no class; used during ssa conversion to indicate pseudo-variables
PEXTERN // global variables
PAUTO // local variables
PAUTOHEAP // local variables or parameters moved to heap
PPARAM // input arguments
PPARAMOUT // output results
PTYPEPARAM // type params
PFUNC // global functions
// Careful: Class is stored in three bits in Node.flags.
_ = uint((1 << 3) - iota) // static assert for iota <= (1 << 3)
)
type Embed struct {
Pos src.XPos
Patterns []string
}