// operand parses a general operand and stores the result in *a.
func (p *Parser) operand(a *obj.Addr) bool {
//fmt.Printf("Operand: %v\n", p.input)
if len(p.input) == 0 {
p.errorf("empty operand: cannot happen")
return false
}
// General address (with a few exceptions) looks like
// $sym±offset(SB)(reg)(index*scale)
// Exceptions are:
//
// R1
// offset
// $offset
// Every piece is optional, so we scan left to right and what
// we discover tells us where we are.
// Prefix: $.
var prefix rune
switch tok := p.peek(); tok {
case '$', '*':
prefix = rune(tok)
p.next()
}
// Symbol: sym±offset(SB)
tok := p.next()
name := tok.String()
if tok.ScanToken == scanner.Ident && !p.atStartOfRegister(name) {
// We have a symbol. Parse $sym±offset(symkind)
p.symbolReference(a, name, prefix)
// fmt.Printf("SYM %s\n", obj.Dconv(&emptyProg, 0, a))
if p.peek() == scanner.EOF {
return true
}
}
// Special register list syntax for arm: [R1,R3-R7]
if tok.ScanToken == '[' {
if prefix != 0 {
p.errorf("illegal use of register list")
}
p.registerList(a)
p.expect(scanner.EOF)
return true
}
// Register: R1
if tok.ScanToken == scanner.Ident && p.atStartOfRegister(name) {
if p.atRegisterShift() {
// ARM shifted register such as R1<<R2 or R1>>2.
a.Type = obj.TYPE_SHIFT
a.Offset = p.registerShift(tok.String(), prefix)
if p.peek() == '(' {
// Can only be a literal register here.
p.next()
tok := p.next()
name := tok.String()
if !p.atStartOfRegister(name) {
p.errorf("expected register; found %s", name)
}
a.Reg, _ = p.registerReference(name)
p.get(')')
}
} else if r1, r2, scale, ok := p.register(tok.String(), prefix); ok {
if scale != 0 {
p.errorf("expected simple register reference")
}
a.Type = obj.TYPE_REG
a.Reg = r1
if r2 != 0 {
// Form is R1:R2. It is on RHS and the second register
// needs to go into the LHS.
panic("cannot happen (Addr.Reg2)")
}
}
// fmt.Printf("REG %s\n", obj.Dconv(&emptyProg, 0, a))
p.expect(scanner.EOF)
return true
}
// Constant.
haveConstant := false
switch tok.ScanToken {
case scanner.Int, scanner.Float, scanner.String, scanner.Char, '+', '-', '~':
haveConstant = true
case '(':
// Could be parenthesized expression or (R). Must be something, though.
tok := p.next()
if tok.ScanToken == scanner.EOF {
p.errorf("missing right parenthesis")
return false
}
rname := tok.String()
p.back()
haveConstant = !p.atStartOfRegister(rname)
if !haveConstant {
p.back() // Put back the '('.
}
}
if haveConstant {
p.back()
if p.have(scanner.Float) {
if prefix != '$' {
p.errorf("floating-point constant must be an immediate")
}
a.Type = obj.TYPE_FCONST
a.Val = p.floatExpr()
// fmt.Printf("FCONST %s\n", obj.Dconv(&emptyProg, 0, a))
p.expect(scanner.EOF)
return true
}
if p.have(scanner.String) {
if prefix != '$' {
p.errorf("string constant must be an immediate")
return false
}
str, err := strconv.Unquote(p.get(scanner.String).String())
if err != nil {
p.errorf("string parse error: %s", err)
}
a.Type = obj.TYPE_SCONST
a.Val = str
// fmt.Printf("SCONST %s\n", obj.Dconv(&emptyProg, 0, a))
p.expect(scanner.EOF)
return true
}
a.Offset = int64(p.expr())
if p.peek() != '(' {
switch prefix {
case '$':
a.Type = obj.TYPE_CONST
case '*':
a.Type = obj.TYPE_INDIR // Can appear but is illegal, will be rejected by the linker.
default:
a.Type = obj.TYPE_MEM
}
// fmt.Printf("CONST %d %s\n", a.Offset, obj.Dconv(&emptyProg, 0, a))
p.expect(scanner.EOF)
return true
}
// fmt.Printf("offset %d \n", a.Offset)
}
// Register indirection: (reg) or (index*scale). We are on the opening paren.
p.registerIndirect(a, prefix)
// fmt.Printf("DONE %s\n", p.arch.Dconv(&emptyProg, 0, a))
p.expect(scanner.EOF)
return true
}
// Naddr rewrites a to refer to n.
// It assumes that a is zeroed on entry.
func Naddr(a *obj.Addr, n *Node) {
if n == nil {
return
}
if n.Type != nil && n.Type.Etype != TIDEAL {
// TODO(rsc): This is undone by the selective clearing of width below,
// to match architectures that were not as aggressive in setting width
// during naddr. Those widths must be cleared to avoid triggering
// failures in gins when it detects real but heretofore latent (and one
// hopes innocuous) type mismatches.
// The type mismatches should be fixed and the clearing below removed.
dowidth(n.Type)
a.Width = n.Type.Width
}
switch n.Op {
default:
a := a // copy to let escape into Ctxt.Dconv
Debug['h'] = 1
Dump("naddr", n)
Fatalf("naddr: bad %v %v", Oconv(int(n.Op), 0), Ctxt.Dconv(a))
case OREGISTER:
a.Type = obj.TYPE_REG
a.Reg = n.Reg
a.Sym = nil
if Thearch.Thechar == '8' { // TODO(rsc): Never clear a->width.
a.Width = 0
}
case OINDREG:
a.Type = obj.TYPE_MEM
a.Reg = n.Reg
a.Sym = Linksym(n.Sym)
a.Offset = n.Xoffset
if a.Offset != int64(int32(a.Offset)) {
Yyerror("offset %d too large for OINDREG", a.Offset)
}
if Thearch.Thechar == '8' { // TODO(rsc): Never clear a->width.
a.Width = 0
}
// n->left is PHEAP ONAME for stack parameter.
// compute address of actual parameter on stack.
case OPARAM:
a.Etype = uint8(Simtype[n.Left.Type.Etype])
a.Width = n.Left.Type.Width
a.Offset = n.Xoffset
a.Sym = Linksym(n.Left.Sym)
a.Type = obj.TYPE_MEM
a.Name = obj.NAME_PARAM
a.Node = n.Left.Orig
case OCLOSUREVAR:
if !Curfn.Func.Needctxt {
Fatalf("closurevar without needctxt")
}
a.Type = obj.TYPE_MEM
a.Reg = int16(Thearch.REGCTXT)
a.Sym = nil
a.Offset = n.Xoffset
case OCFUNC:
Naddr(a, n.Left)
a.Sym = Linksym(n.Left.Sym)
case ONAME:
a.Etype = 0
if n.Type != nil {
a.Etype = uint8(Simtype[n.Type.Etype])
}
a.Offset = n.Xoffset
s := n.Sym
a.Node = n.Orig
//if(a->node >= (Node*)&n)
// fatal("stack node");
if s == nil {
s = Lookup(".noname")
}
if n.Name.Method {
if n.Type != nil {
if n.Type.Sym != nil {
if n.Type.Sym.Pkg != nil {
s = Pkglookup(s.Name, n.Type.Sym.Pkg)
}
}
}
}
a.Type = obj.TYPE_MEM
switch n.Class {
default:
Fatalf("naddr: ONAME class %v %d\n", n.Sym, n.Class)
case PEXTERN:
a.Name = obj.NAME_EXTERN
case PAUTO:
a.Name = obj.NAME_AUTO
case PPARAM, PPARAMOUT:
a.Name = obj.NAME_PARAM
case PFUNC:
a.Name = obj.NAME_EXTERN
a.Type = obj.TYPE_ADDR
a.Width = int64(Widthptr)
s = funcsym(s)
}
a.Sym = Linksym(s)
case ODOT:
// A special case to make write barriers more efficient.
// Taking the address of the first field of a named struct
// is the same as taking the address of the struct.
if n.Left.Type.Etype != TSTRUCT || n.Left.Type.Type.Sym != n.Right.Sym {
Debug['h'] = 1
Dump("naddr", n)
Fatalf("naddr: bad %v %v", Oconv(int(n.Op), 0), Ctxt.Dconv(a))
}
Naddr(a, n.Left)
case OLITERAL:
if Thearch.Thechar == '8' {
a.Width = 0
}
switch n.Val().Ctype() {
default:
Fatalf("naddr: const %v", Tconv(n.Type, obj.FmtLong))
case CTFLT:
a.Type = obj.TYPE_FCONST
a.Val = mpgetflt(n.Val().U.(*Mpflt))
case CTINT, CTRUNE:
a.Sym = nil
a.Type = obj.TYPE_CONST
a.Offset = Mpgetfix(n.Val().U.(*Mpint))
case CTSTR:
datagostring(n.Val().U.(string), a)
case CTBOOL:
a.Sym = nil
a.Type = obj.TYPE_CONST
a.Offset = int64(obj.Bool2int(n.Val().U.(bool)))
case CTNIL:
a.Sym = nil
a.Type = obj.TYPE_CONST
a.Offset = 0
}
case OADDR:
Naddr(a, n.Left)
a.Etype = uint8(Tptr)
if Thearch.Thechar != '0' && Thearch.Thechar != '5' && Thearch.Thechar != '7' && Thearch.Thechar != '9' { // TODO(rsc): Do this even for arm, ppc64.
a.Width = int64(Widthptr)
}
if a.Type != obj.TYPE_MEM {
a := a // copy to let escape into Ctxt.Dconv
Fatalf("naddr: OADDR %v (from %v)", Ctxt.Dconv(a), Oconv(int(n.Left.Op), 0))
}
a.Type = obj.TYPE_ADDR
// itable of interface value
case OITAB:
Naddr(a, n.Left)
if a.Type == obj.TYPE_CONST && a.Offset == 0 {
break // itab(nil)
}
a.Etype = uint8(Tptr)
a.Width = int64(Widthptr)
// pointer in a string or slice
case OSPTR:
Naddr(a, n.Left)
if a.Type == obj.TYPE_CONST && a.Offset == 0 {
break // ptr(nil)
}
a.Etype = uint8(Simtype[Tptr])
a.Offset += int64(Array_array)
a.Width = int64(Widthptr)
// len of string or slice
case OLEN:
Naddr(a, n.Left)
if a.Type == obj.TYPE_CONST && a.Offset == 0 {
break // len(nil)
}
a.Etype = uint8(Simtype[TUINT])
a.Offset += int64(Array_nel)
if Thearch.Thechar != '5' { // TODO(rsc): Do this even on arm.
a.Width = int64(Widthint)
}
// cap of string or slice
case OCAP:
Naddr(a, n.Left)
if a.Type == obj.TYPE_CONST && a.Offset == 0 {
break // cap(nil)
}
a.Etype = uint8(Simtype[TUINT])
a.Offset += int64(Array_cap)
if Thearch.Thechar != '5' { // TODO(rsc): Do this even on arm.
a.Width = int64(Widthint)
}
}
return
}