[dev.regabi] cmd/compile: separate misc for gc split

Misc cleanup for splitting package gc: API tweaks
and boundary adjustments.

The change in ir.NewBlockStmt makes it a drop-in
replacement for liststmt.

Change-Id: I9455fe8ccae7d71fe8ccf390ac96672389bf4f3d
Reviewed-on: https://go-review.googlesource.com/c/go/+/279305
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

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

@@ -143,10 +143,6 @@ type EscEdge struct {
 	notes  *EscNote
 }
 
-func init() {
-	ir.EscFmt = escFmt
-}
-
 // escFmt is called from node printing to print information about escape analysis results.
 func escFmt(n ir.Node) string {
 	text := ""

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

@@ -685,6 +685,21 @@ func (r *importReader) typeExt(t *types.Type) {
 // so we can use index to reference the symbol.
 var typeSymIdx = make(map[*types.Type][2]int64)
 
+func BaseTypeIndex(t *types.Type) int64 {
+	tbase := t
+	if t.IsPtr() && t.Sym() == nil && t.Elem().Sym() != nil {
+		tbase = t.Elem()
+	}
+	i, ok := typeSymIdx[tbase]
+	if !ok {
+		return -1
+	}
+	if t != tbase {
+		return i[1]
+	}
+	return i[0]
+}
+
 func (r *importReader) doInline(fn *ir.Func) {
 	if len(fn.Inl.Body) != 0 {
 		base.Fatalf("%v already has inline body", fn)

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

@@ -54,9 +54,6 @@ func hidePanic() {
 // Target is the package being compiled.
 var Target *ir.Package
 
-// timing data for compiler phases
-var timings Timings
-
 // Main parses flags and Go source files specified in the command-line
 // arguments, type-checks the parsed Go package, compiles functions to machine
 // code, and finally writes the compiled package definition to disk.
@@ -189,6 +186,7 @@ func Main(archInit func(*Arch)) {
 		logopt.LogJsonOption(base.Flag.JSON)
 	}
 
+	ir.EscFmt = escFmt
 	IsIntrinsicCall = isIntrinsicCall
 	SSADumpInline = ssaDumpInline
 	initSSAEnv()
@@ -962,9 +960,11 @@ type lang struct {
 // any language version is supported.
 var langWant lang
 
-// langSupported reports whether language version major.minor is
-// supported in a particular package.
-func langSupported(major, minor int, pkg *types.Pkg) bool {
+// AllowsGoVersion reports whether a particular package
+// is allowed to use Go version major.minor.
+// We assume the imported packages have all been checked,
+// so we only have to check the local package against the -lang flag.
+func AllowsGoVersion(pkg *types.Pkg, major, minor int) bool {
 	if pkg == nil {
 		// TODO(mdempsky): Set Pkg for local types earlier.
 		pkg = types.LocalPkg
@@ -973,13 +973,16 @@ func langSupported(major, minor int, pkg *types.Pkg) bool {
 		// Assume imported packages passed type-checking.
 		return true
 	}
-
 	if langWant.major == 0 && langWant.minor == 0 {
 		return true
 	}
 	return langWant.major > major || (langWant.major == major && langWant.minor >= minor)
 }
 
+func langSupported(major, minor int, pkg *types.Pkg) bool {
+	return AllowsGoVersion(pkg, major, minor)
+}
+
 // checkLang verifies that the -lang flag holds a valid value, and
 // exits if not. It initializes data used by langSupported.
 func checkLang() {

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

@@ -127,8 +127,7 @@ func dumpdata() {
 	addsignats(Target.Externs)
 	dumpsignats()
 	dumptabs()
-	ptabsLen := len(ptabs)
-	itabsLen := len(itabs)
+	numPTabs, numITabs := CountTabs()
 	dumpimportstrings()
 	dumpbasictypes()
 	dumpembeds()
@@ -168,10 +167,11 @@ func dumpdata() {
 	if numExports != len(Target.Exports) {
 		base.Fatalf("Target.Exports changed after compile functions loop")
 	}
-	if ptabsLen != len(ptabs) {
+	newNumPTabs, newNumITabs := CountTabs()
+	if newNumPTabs != numPTabs {
 		base.Fatalf("ptabs changed after compile functions loop")
 	}
-	if itabsLen != len(itabs) {
+	if newNumITabs != numITabs {
 		base.Fatalf("itabs changed after compile functions loop")
 	}
 }

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

@@ -34,6 +34,10 @@ type ptabEntry struct {
 	t *types.Type
 }
 
+func CountTabs() (numPTabs, numITabs int) {
+	return len(ptabs), len(itabs)
+}
+
 // runtime interface and reflection data structures
 var (
 	signatmu    sync.Mutex // protects signatset and signatslice
@@ -1158,13 +1162,9 @@ func dtypesym(t *types.Type) *obj.LSym {
 	if base.Ctxt.Pkgpath != "runtime" || (tbase != types.Types[tbase.Kind()] && tbase != types.ByteType && tbase != types.RuneType && tbase != types.ErrorType) { // int, float, etc
 		// named types from other files are defined only by those files
 		if tbase.Sym() != nil && tbase.Sym().Pkg != types.LocalPkg {
-			if i, ok := typeSymIdx[tbase]; ok {
+			if i := BaseTypeIndex(t); i >= 0 {
 				lsym.Pkg = tbase.Sym().Pkg.Prefix
-				if t != tbase {
-					lsym.SymIdx = int32(i[1])
-				} else {
-					lsym.SymIdx = int32(i[0])
-				}
+				lsym.SymIdx = int32(i)
 				lsym.Set(obj.AttrIndexed, true)
 			}
 			return lsym

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

@@ -11,6 +11,8 @@ import (
 	"time"
 )
 
+var timings Timings
+
 // Timings collects the execution times of labeled phases
 // which are added trough a sequence of Start/Stop calls.
 // Events may be associated with each phase via AddEvent.

src/cmd/compile/internal/ir/stmt.go

@@ -5,6 +5,7 @@
 package ir
 
 import (
+	"cmd/compile/internal/base"
 	"cmd/compile/internal/types"
 	"cmd/internal/src"
 )
@@ -164,6 +165,12 @@ type BlockStmt struct {
 func NewBlockStmt(pos src.XPos, list []Node) *BlockStmt {
 	n := &BlockStmt{}
 	n.pos = pos
+	if !pos.IsKnown() {
+		n.pos = base.Pos
+		if len(list) > 0 {
+			n.pos = list[0].Pos()
+		}
+	}
 	n.op = OBLOCK
 	n.List_.Set(list)
 	return n