[dev.typeparams] cmd/compile: cleanup unified IR file format a little

This CL makes two changes:

1. It moves object symbols and code tags into a new "relocName"
relocation, which should eventually allow getting rid of objStub.

2. It moves the type parameter data into the relocObjDict relocation,
so everything related to writing out dictionaries is contained there.

Change-Id: If0f7ff7d9384e8664957c3180bf6f20e97bcff6e
Reviewed-on: https://go-review.googlesource.com/c/go/+/336051
Trust: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>

1 files changed, 46 insertions, 35 deletions

diff --git a/src/cmd/compile/internal/noder/writer.go b/src/cmd/compile/internal/noder/writer.go
index 48884056f3..bf60246d64 100644
--- a/src/cmd/compile/internal/noder/writer.go
+++ b/src/cmd/compile/internal/noder/writer.go
@@ -505,60 +505,45 @@ func (pw *pkgWriter) objIdx(obj types2.Object) int {
 
 	w := pw.newWriter(relocObj, syncObject1)
 	w.ext = pw.newWriter(relocObjExt, syncObject1)
+	wname := pw.newWriter(relocName, syncObject1)
 	wdict := pw.newWriter(relocObjDict, syncObject1)
 
 	pw.globalsIdx[obj] = w.idx // break cycles
 	assert(w.ext.idx == w.idx)
+	assert(wname.idx == w.idx)
 	assert(wdict.idx == w.idx)
 
 	w.dict = dict
 	w.ext.dict = dict
 
-	// Ident goes first so importer can avoid unnecessary work if
-	// they've already resolved this object.
-	w.qualifiedIdent(obj)
-
-	w.typeParamBounds(objTypeParams(obj))
-
-	w.doObj(obj)
-
+	code := w.doObj(obj)
 	w.flush()
 	w.ext.flush()
 
-	// Done writing out the object description; write out the list of
-	// derived types and instantiated functions found along the way.
-	wdict.len(len(dict.derived))
-	for _, typ := range dict.derived {
-		wdict.reloc(relocType, typ.idx)
-		wdict.bool(typ.needed)
-	}
-	wdict.len(len(dict.funcs))
-	for _, fn := range dict.funcs {
-		wdict.reloc(relocObj, fn.idx)
-		wdict.len(len(fn.explicits))
-		for _, targ := range fn.explicits {
-			wdict.typInfo(targ)
-		}
-	}
+	wname.qualifiedIdent(obj)
+	wname.code(code)
+	wname.flush()
+
+	wdict.objDict(obj, w.dict)
 	wdict.flush()
 
 	return w.idx
 }
 
-func (w *writer) doObj(obj types2.Object) {
+func (w *writer) doObj(obj types2.Object) codeObj {
 	if obj.Pkg() != w.p.curpkg {
-		w.code(objStub)
-		return
+		return objStub
 	}
 
 	switch obj := obj.(type) {
 	default:
 		w.p.unexpected("object", obj)
+		panic("unreachable")
 
 	case *types2.Const:
-		w.code(objConst)
 		w.pos(obj)
 		w.value(obj.Type(), obj.Val())
+		return objConst
 
 	case *types2.Func:
 		decl, ok := w.p.funDecls[obj]
@@ -584,28 +569,26 @@ func (w *writer) doObj(obj types2.Object) {
 			sig = types2.NewSignature(nil, types2.NewTuple(params...), sig.Results(), sig.Variadic())
 		}
 
-		w.code(objFunc)
 		w.pos(obj)
 		w.typeParamNames(sig.TParams())
 		w.signature(sig)
 		w.pos(decl)
 		w.ext.funcExt(obj)
+		return objFunc
 
 	case *types2.TypeName:
 		decl, ok := w.p.typDecls[obj]
 		assert(ok)
 
 		if obj.IsAlias() {
-			w.code(objAlias)
 			w.pos(obj)
 			w.typ(obj.Type())
-			break
+			return objAlias
 		}
 
 		named := obj.Type().(*types2.Named)
 		assert(named.TArgs() == nil)
 
-		w.code(objType)
 		w.pos(obj)
 		w.typeParamNames(named.TParams())
 		w.ext.typeExt(obj)
@@ -616,11 +599,13 @@ func (w *writer) doObj(obj types2.Object) {
 			w.method(named.Method(i))
 		}
 
+		return objType
+
 	case *types2.Var:
-		w.code(objVar)
 		w.pos(obj)
 		w.typ(obj.Type())
 		w.ext.varExt(obj)
+		return objVar
 	}
 }
 
@@ -638,15 +623,41 @@ func (w *writer) value(typ types2.Type, val constant.Value) {
 	w.rawValue(val)
 }
 
-func (w *writer) typeParamBounds(tparams []*types2.TypeName) {
-	w.sync(syncTypeParamBounds)
+// objDict writes the dictionary needed for reading the given object.
+func (w *writer) objDict(obj types2.Object, dict *writerDict) {
+	// TODO(mdempsky): Split objDict into multiple entries? reader.go
+	// doesn't care about the type parameter bounds, and reader2.go
+	// doesn't care about referenced functions.
+
+	w.dict = dict // TODO(mdempsky): This is a bit sketchy.
 
-	w.len(len(w.dict.implicits))
+	w.len(len(dict.implicits))
 
+	tparams := objTypeParams(obj)
 	w.len(len(tparams))
 	for _, tparam := range tparams {
 		w.typ(tparam.Type().(*types2.TypeParam).Bound())
 	}
+
+	nderived := len(dict.derived)
+	w.len(nderived)
+	for _, typ := range dict.derived {
+		w.reloc(relocType, typ.idx)
+		w.bool(typ.needed)
+	}
+
+	nfuncs := len(dict.funcs)
+	w.len(nfuncs)
+	for _, fn := range dict.funcs {
+		w.reloc(relocObj, fn.idx)
+		w.len(len(fn.explicits))
+		for _, targ := range fn.explicits {
+			w.typInfo(targ)
+		}
+	}
+
+	assert(len(dict.derived) == nderived)
+	assert(len(dict.funcs) == nfuncs)
 }
 
 func (w *writer) typeParamNames(tparams []*types2.TypeName) {