cmd/compile: provide pos and curfn to temp

Concurrent compilation requires providing an
explicit position and curfn to temp.
This implementation of tempAt temporarily
continues to use the globals lineno and Curfn,
so as not to collide with mdempsky's
work for #19683 eliminating the Curfn dependency
from func nod.

Updates #15756
Updates #19683

Change-Id: Ib3149ca4b0740e9f6eea44babc6f34cdd63028a9
Reviewed-on: https://go-review.googlesource.com/38592
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

src/cmd/compile/internal/gc/gen.go

@@ -8,6 +8,7 @@ package gc
 
 import (
 	"cmd/internal/obj"
+	"cmd/internal/src"
 	"fmt"
 )
 
@@ -219,3 +220,10 @@ func temp(t *Type) *Node {
 	n.Sym.Def.SetUsed(true)
 	return n.Orig
 }
+
+func tempAt(pos src.XPos, curfn *Node, t *Type) *Node {
+	// TODO(mdempsky/josharian): Remove all reads and writes of lineno and Curfn.
+	lineno = pos
+	Curfn = curfn
+	return temp(t)
+}

src/cmd/compile/internal/gc/pgen.go

@@ -8,6 +8,7 @@ import (
 	"cmd/compile/internal/ssa"
 	"cmd/internal/dwarf"
 	"cmd/internal/obj"
+	"cmd/internal/src"
 	"cmd/internal/sys"
 	"fmt"
 	"sort"
@@ -208,7 +209,7 @@ func (s *ssafn) AllocFrame(f *ssa.Func) {
 	}
 
 	if f.Config.NeedsFpScratch {
-		scratchFpMem = temp(Types[TUINT64])
+		scratchFpMem = tempAt(src.NoXPos, s.curfn, Types[TUINT64])
 		scratchFpMem.SetUsed(scratchUsed)
 	}
 

src/cmd/compile/internal/gc/ssa.go

@@ -92,6 +92,7 @@ func buildssa(fn *Node) *ssa.Func {
 		curfn: fn,
 		log:   printssa,
 	}
+	s.curfn = fn
 
 	s.f = ssa.NewFunc(&fe)
 	s.config = ssaConfig
@@ -203,6 +204,9 @@ type state struct {
 	// function we're building
 	f *ssa.Func
 
+	// Node for function
+	curfn *Node
+
 	// labels and labeled control flow nodes (OFOR, OFORUNTIL, OSWITCH, OSELECT) in f
 	labels       map[string]*ssaLabel
 	labeledNodes map[*Node]*ssaLabel
@@ -4082,7 +4086,7 @@ func (s *state) dottype(n *Node, commaok bool) (res, resok *ssa.Value) {
 	if commaok && !canSSAType(n.Type) {
 		// unSSAable type, use temporary.
 		// TODO: get rid of some of these temporaries.
-		tmp = temp(n.Type)
+		tmp = tempAt(n.Pos, s.curfn, n.Type)
 		addr = s.addr(tmp, false)
 		s.vars[&memVar] = s.newValue1A(ssa.OpVarDef, ssa.TypeMem, tmp, s.mem())
 	}
@@ -4713,8 +4717,8 @@ func (e *ssafn) StringData(s string) interface{} {
 	return aux
 }
 
-func (e *ssafn) Auto(t ssa.Type) ssa.GCNode {
-	n := temp(t.(*Type)) // Note: adds new auto to Curfn.Func.Dcl list
+func (e *ssafn) Auto(pos src.XPos, t ssa.Type) ssa.GCNode {
+	n := tempAt(pos, e.curfn, t.(*Type)) // Note: adds new auto to e.curfn.Func.Dcl list
 	return n
 }
 

src/cmd/compile/internal/ssa/config.go

@@ -101,7 +101,7 @@ type Frontend interface {
 
 	// Auto returns a Node for an auto variable of the given type.
 	// The SSA compiler uses this function to allocate space for spills.
-	Auto(Type) GCNode
+	Auto(src.XPos, Type) GCNode
 
 	// Given the name for a compound type, returns the name we should use
 	// for the parts of that compound type.

src/cmd/compile/internal/ssa/export_test.go

@@ -76,7 +76,7 @@ func (d *DummyAuto) String() string {
 func (DummyFrontend) StringData(s string) interface{} {
 	return nil
 }
-func (DummyFrontend) Auto(t Type) GCNode {
+func (DummyFrontend) Auto(pos src.XPos, t Type) GCNode {
 	return &DummyAuto{t: t, s: "aDummyAuto"}
 }
 func (d DummyFrontend) SplitString(s LocalSlot) (LocalSlot, LocalSlot) {

src/cmd/compile/internal/ssa/loop_test.go

@@ -5,6 +5,7 @@
 package ssa
 
 import (
+	"cmd/internal/src"
 	"testing"
 )
 
@@ -49,7 +50,7 @@ func TestLoopConditionS390X(t *testing.T) {
 			Valu("mem", OpInitMem, TypeMem, 0, nil),
 			Valu("SP", OpSP, TypeUInt64, 0, nil),
 			Valu("ret", OpAddr, TypeInt64Ptr, 0, nil, "SP"),
-			Valu("N", OpArg, TypeInt64, 0, c.Frontend().Auto(TypeInt64)),
+			Valu("N", OpArg, TypeInt64, 0, c.Frontend().Auto(src.NoXPos, TypeInt64)),
 			Valu("starti", OpConst64, TypeInt64, 0, nil),
 			Valu("startsum", OpConst64, TypeInt64, 0, nil),
 			Goto("b1")),

src/cmd/compile/internal/ssa/regalloc.go

@@ -2080,13 +2080,7 @@ func (e *edgeState) findRegFor(typ Type) Location {
 		return &e.s.registers[pickReg(x)]
 	}
 
-	// No register is available. Allocate a temp location to spill a register to.
-	// The type of the slot is immaterial - it will not be live across
-	// any safepoint. Just use a type big enough to hold any register.
-	typ = types.Int64
-	t := LocalSlot{e.s.f.fe.Auto(typ), typ, 0}
-	// TODO: reuse these slots.
-
+	// No register is available.
 	// Pick a register to spill.
 	for _, vid := range e.cachedVals {
 		a := e.cache[vid]
@@ -2094,6 +2088,11 @@ func (e *edgeState) findRegFor(typ Type) Location {
 			if r, ok := e.s.f.getHome(c.ID).(*Register); ok && m>>uint(r.num)&1 != 0 {
 				if !c.rematerializeable() {
 					x := e.p.NewValue1(c.Pos, OpStoreReg, c.Type, c)
+					// Allocate a temp location to spill a register to.
+					// The type of the slot is immaterial - it will not be live across
+					// any safepoint. Just use a type big enough to hold any register.
+					t := LocalSlot{e.s.f.fe.Auto(c.Pos, types.Int64), types.Int64, 0}
+					// TODO: reuse these slots.
 					e.set(t, vid, x, false, c.Pos)
 					if e.s.f.pass.debug > regDebug {
 						fmt.Printf("  SPILL %s->%s %s\n", r.Name(), t.Name(), x.LongString())

src/cmd/compile/internal/ssa/regalloc_test.go

@@ -4,7 +4,10 @@
 
 package ssa
 
-import "testing"
+import (
+	"cmd/internal/src"
+	"testing"
+)
 
 func TestLiveControlOps(t *testing.T) {
 	c := testConfig(t)
@@ -39,8 +42,8 @@ func TestSpillWithLoop(t *testing.T) {
 	f := c.Fun("entry",
 		Bloc("entry",
 			Valu("mem", OpInitMem, TypeMem, 0, nil),
-			Valu("ptr", OpArg, TypeInt64Ptr, 0, c.Frontend().Auto(TypeInt64)),
-			Valu("cond", OpArg, TypeBool, 0, c.Frontend().Auto(TypeBool)),
+			Valu("ptr", OpArg, TypeInt64Ptr, 0, c.Frontend().Auto(src.NoXPos, TypeInt64)),
+			Valu("cond", OpArg, TypeBool, 0, c.Frontend().Auto(src.NoXPos, TypeBool)),
 			Valu("ld", OpAMD64MOVQload, TypeInt64, 0, nil, "ptr", "mem"), // this value needs a spill
 			Goto("loop"),
 		),

src/cmd/compile/internal/ssa/stackalloc.go

@@ -246,7 +246,7 @@ func (s *stackAllocState) stackalloc() {
 			// If there is no unused stack slot, allocate a new one.
 			if i == len(locs) {
 				s.nAuto++
-				locs = append(locs, LocalSlot{N: f.fe.Auto(v.Type), Type: v.Type, Off: 0})
+				locs = append(locs, LocalSlot{N: f.fe.Auto(v.Pos, v.Type), Type: v.Type, Off: 0})
 				locations[v.Type] = locs
 			}
 			// Use the stack variable at that index for v.

src/cmd/compile/internal/ssa/writebarrier.go

@@ -267,7 +267,7 @@ func wbcall(pos src.XPos, b *Block, fn *obj.LSym, typ interface{}, ptr, val, mem
 		// a function call). Marshaling the args to typedmemmove might clobber the
 		// value we're trying to move.
 		t := val.Type.ElemType()
-		tmp = b.Func.fe.Auto(t)
+		tmp = b.Func.fe.Auto(val.Pos, t)
 		aux := &AutoSymbol{Typ: t, Node: tmp}
 		mem = b.NewValue1A(pos, OpVarDef, TypeMem, tmp, mem)
 		tmpaddr := b.NewValue1A(pos, OpAddr, t.PtrTo(), aux, sp)