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cmd/compile: document sinit ctxt and pass/kind arguments
No functional changes. Passes toolstash -cmp. Change-Id: I1ad467e574fd2ea80ab1459c0c943d9ff66c23ec Reviewed-on: https://go-review.googlesource.com/26755 Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: David Crawshaw <crawshaw@golang.org>
This commit is contained in:
Josh Bleecher Snyder
parent
cd2d5ee048
commit
7b5df0c195
@ -400,7 +400,7 @@ func staticassign(l *Node, r *Node, out *[]*Node) bool {
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switch r.Left.Op {
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case OARRAYLIT, OSLICELIT, OMAPLIT, OSTRUCTLIT:
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// Init pointer.
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a := staticname(r.Left.Type, 1)
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a := staticname(r.Left.Type, inNonInitFunction)
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inittemps[r] = a
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gdata(l, Nod(OADDR, a, nil), int(l.Type.Width))
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@ -425,7 +425,7 @@ func staticassign(l *Node, r *Node, out *[]*Node) bool {
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// Init slice.
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bound := r.Right.Int64()
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ta := typArray(r.Type.Elem(), bound)
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a := staticname(ta, 1)
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a := staticname(ta, inNonInitFunction)
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inittemps[r] = a
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n := *l
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n.Xoffset = l.Xoffset + int64(Array_array)
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@ -485,15 +485,32 @@ func staticassign(l *Node, r *Node, out *[]*Node) bool {
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return false
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}
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// initContext is the context in which static data is populated.
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// It is either in an init function or in any other function.
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// Static data populated in an init function will be written either
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// zero times (as a readonly, static data symbol) or
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// one time (during init function execution).
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// Either way, there is no opportunity for races or further modification,
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// so the data can be written to a (possibly readonly) data symbol.
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// Static data populated in any other function needs to be local to
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// that function to allow multiple instances of that function
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// to execute concurrently without clobbering each others' data.
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type initContext uint8
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const (
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inInitFunction initContext = iota
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inNonInitFunction
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)
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// from here down is the walk analysis
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// of composite literals.
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// most of the work is to generate
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// data statements for the constant
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// part of the composite literal.
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func staticname(t *Type, ctxt int) *Node {
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func staticname(t *Type, ctxt initContext) *Node {
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n := newname(LookupN("statictmp_", statuniqgen))
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statuniqgen++
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if ctxt == 0 {
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if ctxt == inInitFunction {
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n.Name.Readonly = true
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}
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addvar(n, t, PEXTERN)
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@ -579,9 +596,26 @@ func isStaticCompositeLiteral(n *Node) bool {
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return false
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}
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// initKind is a kind of static initialization: static, dynamic, or local.
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// Static initialization represents literals and
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// literal components of composite literals.
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// Dynamic initialization represents non-literals and
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// non-literal components of composite literals.
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// LocalCode initializion represents initialization
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// that occurs purely in generated code local to the function of use.
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// Initialization code is sometimes generated in passes,
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// first static then dynamic.
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type initKind uint8
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const (
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initKindStatic initKind = iota + 1
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initKindDynamic
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initKindLocalCode
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)
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// fixedlit handles struct, array, and slice literals.
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// TODO: expand documentation.
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func fixedlit(ctxt int, pass int, n *Node, var_ *Node, init *Nodes) {
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func fixedlit(ctxt initContext, kind initKind, n *Node, var_ *Node, init *Nodes) {
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var indexnode func(*Node) *Node
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switch n.Op {
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case OARRAYLIT, OSLICELIT:
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@ -601,7 +635,7 @@ func fixedlit(ctxt int, pass int, n *Node, var_ *Node, init *Nodes) {
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switch value.Op {
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case OSLICELIT:
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if (pass == 1 && ctxt != 0) || (pass == 2 && ctxt == 0) {
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if (kind == initKindStatic && ctxt == inNonInitFunction) || (kind == initKindDynamic && ctxt == inInitFunction) {
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a := indexnode(index)
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slicelit(ctxt, value, a, init)
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continue
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@ -609,7 +643,7 @@ func fixedlit(ctxt int, pass int, n *Node, var_ *Node, init *Nodes) {
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case OARRAYLIT, OSTRUCTLIT:
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a := indexnode(index)
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fixedlit(ctxt, pass, value, a, init)
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fixedlit(ctxt, kind, value, a, init)
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continue
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}
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@ -617,7 +651,7 @@ func fixedlit(ctxt int, pass int, n *Node, var_ *Node, init *Nodes) {
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if n.Op == OARRAYLIT {
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islit = islit && isliteral(index)
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}
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if (pass == 1 && !islit) || (pass == 2 && islit) {
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if (kind == initKindStatic && !islit) || (kind == initKindDynamic && islit) {
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continue
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}
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@ -625,32 +659,35 @@ func fixedlit(ctxt int, pass int, n *Node, var_ *Node, init *Nodes) {
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setlineno(value)
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a := Nod(OAS, indexnode(index), value)
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a = typecheck(a, Etop)
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if pass == 1 {
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switch kind {
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case initKindStatic:
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a = walkexpr(a, init) // add any assignments in r to top
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if a.Op != OAS {
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Fatalf("fixedlit: not as")
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}
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a.IsStatic = true
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} else {
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case initKindDynamic, initKindLocalCode:
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a = orderstmtinplace(a)
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a = walkstmt(a)
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default:
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Fatalf("fixedlit: bad kind %d", kind)
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}
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init.Append(a)
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}
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}
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func slicelit(ctxt int, n *Node, var_ *Node, init *Nodes) {
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func slicelit(ctxt initContext, n *Node, var_ *Node, init *Nodes) {
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// make an array type corresponding the number of elements we have
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t := typArray(n.Type.Elem(), n.Right.Int64())
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dowidth(t)
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if ctxt != 0 {
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if ctxt == inNonInitFunction {
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// put everything into static array
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vstat := staticname(t, ctxt)
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fixedlit(ctxt, 1, n, vstat, init)
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fixedlit(ctxt, 2, n, vstat, init)
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fixedlit(ctxt, initKindStatic, n, vstat, init)
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fixedlit(ctxt, initKindDynamic, n, vstat, init)
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// copy static to slice
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a := Nod(OSLICE, vstat, nil)
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@ -688,7 +725,7 @@ func slicelit(ctxt int, n *Node, var_ *Node, init *Nodes) {
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mode := getdyn(n, true)
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if mode&initConst != 0 {
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vstat = staticname(t, ctxt)
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fixedlit(ctxt, 1, n, vstat, init)
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fixedlit(ctxt, initKindStatic, n, vstat, init)
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}
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// make new auto *array (3 declare)
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@ -754,7 +791,7 @@ func slicelit(ctxt int, n *Node, var_ *Node, init *Nodes) {
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break
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case OARRAYLIT, OSTRUCTLIT:
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fixedlit(ctxt, 2, value, a, init)
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fixedlit(ctxt, initKindDynamic, value, a, init)
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continue
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}
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@ -781,8 +818,8 @@ func slicelit(ctxt int, n *Node, var_ *Node, init *Nodes) {
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init.Append(a)
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}
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func maplit(ctxt int, n *Node, m *Node, init *Nodes) {
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ctxt = 0
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func maplit(ctxt initContext, n *Node, m *Node, init *Nodes) {
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ctxt = inInitFunction
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// make the map var
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nerr := nerrors
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@ -928,7 +965,7 @@ func maplit(ctxt int, n *Node, m *Node, init *Nodes) {
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}
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}
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func anylit(ctxt int, n *Node, var_ *Node, init *Nodes) {
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func anylit(ctxt initContext, n *Node, var_ *Node, init *Nodes) {
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t := n.Type
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switch n.Op {
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default:
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@ -966,15 +1003,15 @@ func anylit(ctxt int, n *Node, var_ *Node, init *Nodes) {
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}
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if var_.isSimpleName() && n.List.Len() > 4 {
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if ctxt == 0 {
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if ctxt == inInitFunction {
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// lay out static data
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vstat := staticname(t, ctxt)
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pass1ctxt := ctxt
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litctxt := ctxt
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if n.Op == OARRAYLIT {
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pass1ctxt = 1
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litctxt = inNonInitFunction
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}
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fixedlit(pass1ctxt, 1, n, vstat, init)
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fixedlit(litctxt, initKindStatic, n, vstat, init)
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// copy static to var
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a := Nod(OAS, var_, vstat)
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@ -984,13 +1021,13 @@ func anylit(ctxt int, n *Node, var_ *Node, init *Nodes) {
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init.Append(a)
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// add expressions to automatic
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fixedlit(ctxt, 2, n, var_, init)
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fixedlit(ctxt, initKindDynamic, n, var_, init)
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break
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}
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fixedlit(ctxt, 1, n, var_, init)
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fixedlit(ctxt, 2, n, var_, init)
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fixedlit(ctxt, initKindStatic, n, var_, init)
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fixedlit(ctxt, initKindDynamic, n, var_, init)
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break
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}
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@ -1008,7 +1045,7 @@ func anylit(ctxt int, n *Node, var_ *Node, init *Nodes) {
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init.Append(a)
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}
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fixedlit(ctxt, 3, n, var_, init)
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fixedlit(ctxt, initKindLocalCode, n, var_, init)
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case OSLICELIT:
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slicelit(ctxt, n, var_, init)
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@ -1039,14 +1076,6 @@ func oaslit(n *Node, init *Nodes) bool {
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return false
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}
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// context is init() function.
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// implies generated data executed
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// exactly once and not subject to races.
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ctxt := 0
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// if(n->dodata == 1)
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// ctxt = 1;
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switch n.Right.Op {
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default:
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// not a special composit literal assignment
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@ -1057,7 +1086,7 @@ func oaslit(n *Node, init *Nodes) bool {
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// not a special composit literal assignment
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return false
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}
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anylit(ctxt, n.Right, n.Left, init)
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anylit(inInitFunction, n.Right, n.Left, init)
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}
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n.Op = OEMPTY
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@ -1636,14 +1636,14 @@ opswitch:
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if isStaticCompositeLiteral(n) {
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// n can be directly represented in the read-only data section.
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// Make direct reference to the static data. See issue 12841.
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vstat := staticname(n.Type, 0)
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fixedlit(0, 1, n, vstat, init)
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vstat := staticname(n.Type, inInitFunction)
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fixedlit(inInitFunction, initKindStatic, n, vstat, init)
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n = vstat
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n = typecheck(n, Erv)
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break
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}
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var_ := temp(n.Type)
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anylit(0, n, var_, init)
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anylit(inInitFunction, n, var_, init)
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n = var_
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case OSEND:
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