1 files changed, 357 insertions, 0 deletions
diff --git a/src/cmd/compile/internal/noder/irgen.go b/src/cmd/compile/internal/noder/irgen.go
new file mode 100644
index 0000000..52224c4
--- /dev/null
+++ b/src/cmd/compile/internal/noder/irgen.go
@@ -0,0 +1,357 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package noder
+
+import (
+	"fmt"
+	"os"
+
+	"cmd/compile/internal/base"
+	"cmd/compile/internal/dwarfgen"
+	"cmd/compile/internal/ir"
+	"cmd/compile/internal/syntax"
+	"cmd/compile/internal/typecheck"
+	"cmd/compile/internal/types"
+	"cmd/compile/internal/types2"
+	"cmd/internal/src"
+)
+
+// checkFiles configures and runs the types2 checker on the given
+// parsed source files and then returns the result.
+func checkFiles(noders []*noder) (posMap, *types2.Package, *types2.Info) {
+	if base.SyntaxErrors() != 0 {
+		base.ErrorExit()
+	}
+
+	// setup and syntax error reporting
+	var m posMap
+	files := make([]*syntax.File, len(noders))
+	for i, p := range noders {
+		m.join(&p.posMap)
+		files[i] = p.file
+	}
+
+	// typechecking
+	ctxt := types2.NewContext()
+	importer := gcimports{
+		ctxt:     ctxt,
+		packages: map[string]*types2.Package{"unsafe": types2.Unsafe},
+	}
+	conf := types2.Config{
+		Context:               ctxt,
+		GoVersion:             base.Flag.Lang,
+		IgnoreLabels:          true, // parser already checked via syntax.CheckBranches mode
+		CompilerErrorMessages: true, // use error strings matching existing compiler errors
+		Error: func(err error) {
+			terr := err.(types2.Error)
+			base.ErrorfAt(m.makeXPos(terr.Pos), "%s", terr.Msg)
+		},
+		Importer: &importer,
+		Sizes:    &gcSizes{},
+	}
+	info := &types2.Info{
+		Types:      make(map[syntax.Expr]types2.TypeAndValue),
+		Defs:       make(map[*syntax.Name]types2.Object),
+		Uses:       make(map[*syntax.Name]types2.Object),
+		Selections: make(map[*syntax.SelectorExpr]*types2.Selection),
+		Implicits:  make(map[syntax.Node]types2.Object),
+		Scopes:     make(map[syntax.Node]*types2.Scope),
+		Instances:  make(map[*syntax.Name]types2.Instance),
+		// expand as needed
+	}
+
+	pkg, err := conf.Check(base.Ctxt.Pkgpath, files, info)
+
+	base.ExitIfErrors()
+	if err != nil {
+		base.FatalfAt(src.NoXPos, "conf.Check error: %v", err)
+	}
+
+	return m, pkg, info
+}
+
+// check2 type checks a Go package using types2, and then generates IR
+// using the results.
+func check2(noders []*noder) {
+	m, pkg, info := checkFiles(noders)
+
+	if base.Flag.G < 2 {
+		os.Exit(0)
+	}
+
+	g := irgen{
+		target: typecheck.Target,
+		self:   pkg,
+		info:   info,
+		posMap: m,
+		objs:   make(map[types2.Object]*ir.Name),
+		typs:   make(map[types2.Type]*types.Type),
+	}
+	g.generate(noders)
+
+	if base.Flag.G < 3 {
+		os.Exit(0)
+	}
+}
+
+// Information about sub-dictionary entries in a dictionary
+type subDictInfo struct {
+	// Call or XDOT node that requires a dictionary.
+	callNode ir.Node
+	// Saved CallExpr.X node (*ir.SelectorExpr or *InstExpr node) for a generic
+	// method or function call, since this node will get dropped when the generic
+	// method/function call is transformed to a call on the instantiated shape
+	// function. Nil for other kinds of calls or XDOTs.
+	savedXNode ir.Node
+}
+
+// dictInfo is the dictionary format for an instantiation of a generic function with
+// particular shapes. shapeParams, derivedTypes, subDictCalls, and itabConvs describe
+// the actual dictionary entries in order, and the remaining fields are other info
+// needed in doing dictionary processing during compilation.
+type dictInfo struct {
+	// Types substituted for the type parameters, which are shape types.
+	shapeParams []*types.Type
+	// All types derived from those typeparams used in the instantiation.
+	derivedTypes []*types.Type
+	// Nodes in the instantiation that requires a subdictionary. Includes
+	// method and function calls (OCALL), function values (OFUNCINST), method
+	// values/expressions (OXDOT).
+	subDictCalls []subDictInfo
+	// Nodes in the instantiation that are a conversion from a typeparam/derived
+	// type to a specific interface.
+	itabConvs []ir.Node
+
+	// Mapping from each shape type that substitutes a type param, to its
+	// type bound (which is also substituted with shapes if it is parameterized)
+	shapeToBound map[*types.Type]*types.Type
+
+	// For type switches on nonempty interfaces, a map from OTYPE entries of
+	// HasShape type, to the interface type we're switching from.
+	type2switchType map[ir.Node]*types.Type
+
+	startSubDict  int // Start of dict entries for subdictionaries
+	startItabConv int // Start of dict entries for itab conversions
+	dictLen       int // Total number of entries in dictionary
+}
+
+// instInfo is information gathered on an shape instantiation of a function.
+type instInfo struct {
+	fun       *ir.Func // The instantiated function (with body)
+	dictParam *ir.Name // The node inside fun that refers to the dictionary param
+
+	dictInfo *dictInfo
+}
+
+type irgen struct {
+	target *ir.Package
+	self   *types2.Package
+	info   *types2.Info
+
+	posMap
+	objs   map[types2.Object]*ir.Name
+	typs   map[types2.Type]*types.Type
+	marker dwarfgen.ScopeMarker
+
+	// laterFuncs records tasks that need to run after all declarations
+	// are processed.
+	laterFuncs []func()
+	// haveEmbed indicates whether the current node belongs to file that
+	// imports "embed" package.
+	haveEmbed bool
+
+	// exprStmtOK indicates whether it's safe to generate expressions or
+	// statements yet.
+	exprStmtOK bool
+
+	// types which we need to finish, by doing g.fillinMethods.
+	typesToFinalize []*typeDelayInfo
+
+	// True when we are compiling a top-level generic function or method. Use to
+	// avoid adding closures of generic functions/methods to the target.Decls
+	// list.
+	topFuncIsGeneric bool
+
+	// The context during type/function/method declarations that is used to
+	// uniquely name type parameters. We need unique names for type params so we
+	// can be sure they match up correctly between types2-to-types1 translation
+	// and types1 importing.
+	curDecl string
+}
+
+// genInst has the information for creating needed instantiations and modifying
+// functions to use instantiations.
+type genInst struct {
+	dnum int // for generating unique dictionary variables
+
+	// Map from the names of all instantiations to information about the
+	// instantiations.
+	instInfoMap map[*types.Sym]*instInfo
+
+	// Dictionary syms which we need to finish, by writing out any itabconv
+	// entries.
+	dictSymsToFinalize []*delayInfo
+
+	// New instantiations created during this round of buildInstantiations().
+	newInsts []ir.Node
+}
+
+func (g *irgen) later(fn func()) {
+	g.laterFuncs = append(g.laterFuncs, fn)
+}
+
+type delayInfo struct {
+	gf     *ir.Name
+	targs  []*types.Type
+	sym    *types.Sym
+	off    int
+	isMeth bool
+}
+
+type typeDelayInfo struct {
+	typ  *types2.Named
+	ntyp *types.Type
+}
+
+func (g *irgen) generate(noders []*noder) {
+	types.LocalPkg.Name = g.self.Name()
+	types.LocalPkg.Height = g.self.Height()
+	typecheck.TypecheckAllowed = true
+
+	// Prevent size calculations until we set the underlying type
+	// for all package-block defined types.
+	types.DeferCheckSize()
+
+	// At this point, types2 has already handled name resolution and
+	// type checking. We just need to map from its object and type
+	// representations to those currently used by the rest of the
+	// compiler. This happens in a few passes.
+
+	// 1. Process all import declarations. We use the compiler's own
+	// importer for this, rather than types2's gcimporter-derived one,
+	// to handle extensions and inline function bodies correctly.
+	//
+	// Also, we need to do this in a separate pass, because mappings are
+	// instantiated on demand. If we interleaved processing import
+	// declarations with other declarations, it's likely we'd end up
+	// wanting to map an object/type from another source file, but not
+	// yet have the import data it relies on.
+	declLists := make([][]syntax.Decl, len(noders))
+Outer:
+	for i, p := range noders {
+		g.pragmaFlags(p.file.Pragma, ir.GoBuildPragma)
+		for j, decl := range p.file.DeclList {
+			switch decl := decl.(type) {
+			case *syntax.ImportDecl:
+				g.importDecl(p, decl)
+			default:
+				declLists[i] = p.file.DeclList[j:]
+				continue Outer // no more ImportDecls
+			}
+		}
+	}
+
+	// 2. Process all package-block type declarations. As with imports,
+	// we need to make sure all types are properly instantiated before
+	// trying to map any expressions that utilize them. In particular,
+	// we need to make sure type pragmas are already known (see comment
+	// in irgen.typeDecl).
+	//
+	// We could perhaps instead defer processing of package-block
+	// variable initializers and function bodies, like noder does, but
+	// special-casing just package-block type declarations minimizes the
+	// differences between processing package-block and function-scoped
+	// declarations.
+	for _, declList := range declLists {
+		for _, decl := range declList {
+			switch decl := decl.(type) {
+			case *syntax.TypeDecl:
+				g.typeDecl((*ir.Nodes)(&g.target.Decls), decl)
+			}
+		}
+	}
+	types.ResumeCheckSize()
+
+	// 3. Process all remaining declarations.
+	for i, declList := range declLists {
+		old := g.haveEmbed
+		g.haveEmbed = noders[i].importedEmbed
+		g.decls((*ir.Nodes)(&g.target.Decls), declList)
+		g.haveEmbed = old
+	}
+	g.exprStmtOK = true
+
+	// 4. Run any "later" tasks. Avoid using 'range' so that tasks can
+	// recursively queue further tasks. (Not currently utilized though.)
+	for len(g.laterFuncs) > 0 {
+		fn := g.laterFuncs[0]
+		g.laterFuncs = g.laterFuncs[1:]
+		fn()
+	}
+
+	if base.Flag.W > 1 {
+		for _, n := range g.target.Decls {
+			s := fmt.Sprintf("\nafter noder2 %v", n)
+			ir.Dump(s, n)
+		}
+	}
+
+	for _, p := range noders {
+		// Process linkname and cgo pragmas.
+		p.processPragmas()
+
+		// Double check for any type-checking inconsistencies. This can be
+		// removed once we're confident in IR generation results.
+		syntax.Crawl(p.file, func(n syntax.Node) bool {
+			g.validate(n)
+			return false
+		})
+	}
+
+	if base.Flag.Complete {
+		for _, n := range g.target.Decls {
+			if fn, ok := n.(*ir.Func); ok {
+				if fn.Body == nil && fn.Nname.Sym().Linkname == "" {
+					base.ErrorfAt(fn.Pos(), "missing function body")
+				}
+			}
+		}
+	}
+
+	// Check for unusual case where noder2 encounters a type error that types2
+	// doesn't check for (e.g. notinheap incompatibility).
+	base.ExitIfErrors()
+
+	typecheck.DeclareUniverse()
+
+	// Create any needed instantiations of generic functions and transform
+	// existing and new functions to use those instantiations.
+	BuildInstantiations()
+
+	// Remove all generic functions from g.target.Decl, since they have been
+	// used for stenciling, but don't compile. Generic functions will already
+	// have been marked for export as appropriate.
+	j := 0
+	for i, decl := range g.target.Decls {
+		if decl.Op() != ir.ODCLFUNC || !decl.Type().HasTParam() {
+			g.target.Decls[j] = g.target.Decls[i]
+			j++
+		}
+	}
+	g.target.Decls = g.target.Decls[:j]
+
+	base.Assertf(len(g.laterFuncs) == 0, "still have %d later funcs", len(g.laterFuncs))
+}
+
+func (g *irgen) unhandled(what string, p poser) {
+	base.FatalfAt(g.pos(p), "unhandled %s: %T", what, p)
+	panic("unreachable")
+}
+
+// delayTransform returns true if we should delay all transforms, because we are
+// creating the nodes for a generic function/method.
+func (g *irgen) delayTransform() bool {
+	return g.topFuncIsGeneric
+}