cmd/compile/internal/ssa: simplify NewFunc API

Add Config and Cache as params rather than documenting that the caller
has to set them manually.

Change-Id: I8d530be695a0c94bcc4211b496d6e57ec2fff029
Reviewed-on: https://go-review.googlesource.com/c/go/+/526515
Auto-Submit: Matthew Dempsky <mdempsky@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>

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

@@ -84,9 +84,17 @@ type LocalSlotSplitKey struct {
 }
 
 // NewFunc returns a new, empty function object.
-// Caller must set f.Config and f.Cache before using f.
-func NewFunc(fe Frontend) *Func {
-	return &Func{fe: fe, NamedValues: make(map[LocalSlot][]*Value), CanonicalLocalSlots: make(map[LocalSlot]*LocalSlot), CanonicalLocalSplits: make(map[LocalSlotSplitKey]*LocalSlot)}
+// Caller must reset cache before calling NewFunc.
+func (c *Config) NewFunc(fe Frontend, cache *Cache) *Func {
+	return &Func{
+		fe:     fe,
+		Config: c,
+		Cache:  cache,
+
+		NamedValues:          make(map[LocalSlot][]*Value),
+		CanonicalLocalSlots:  make(map[LocalSlot]*LocalSlot),
+		CanonicalLocalSplits: make(map[LocalSlotSplitKey]*LocalSlot),
+	}
 }
 
 // NumBlocks returns an integer larger than the id of any Block in the Func.

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

@@ -152,12 +152,10 @@ func AuxCallLSym(name string) *AuxCall {
 // supplied to one of the Bloc functions. Each of the bloc names and
 // valu names should be unique across the Fun.
 func (c *Conf) Fun(entry string, blocs ...bloc) fun {
-	f := NewFunc(c.Frontend())
-	f.Config = c.config
 	// TODO: Either mark some SSA tests as t.Parallel,
 	// or set up a shared Cache and Reset it between tests.
 	// But not both.
-	f.Cache = new(Cache)
+	f := c.config.NewFunc(c.Frontend(), new(Cache))
 	f.pass = &emptyPass
 	f.cachedLineStarts = newXposmap(map[int]lineRange{0: {0, 100}, 1: {0, 100}, 2: {0, 100}, 3: {0, 100}, 4: {0, 100}})
 

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

@@ -344,12 +344,12 @@ func buildssa(fn *ir.Func, worker int) *ssa.Func {
 	}
 	s.curfn = fn
 
-	s.f = ssa.NewFunc(&fe)
+	cache := &ssaCaches[worker]
+	cache.Reset()
+
+	s.f = ssaConfig.NewFunc(&fe, cache)
 	s.config = ssaConfig
 	s.f.Type = fn.Type()
-	s.f.Config = ssaConfig
-	s.f.Cache = &ssaCaches[worker]
-	s.f.Cache.Reset()
 	s.f.Name = name
 	s.f.PrintOrHtmlSSA = printssa
 	if fn.Pragma&ir.Nosplit != 0 {