gopls: implement reference support for goasm files

This commit adds support for reference relationships in Go assembly (.goasm) files within the references file. It implements the logic to identify and record references in goasm file types, enabling reference lookups and navigation for Go assembly code.

Updates golang/go#71754

Author: groot-guo

gopls/internal/cache/package.go

@@ -206,3 +206,17 @@ func (p *Package) TypeErrors() []types.Error {
 func (p *Package) AsmFiles() []*asm.File {
 	return p.pkg.asmFiles
 }
+
+func (p *Package) AsmFile(uri protocol.DocumentURI) (*asm.File, error) {
+	return p.pkg.AsmFile(uri)
+}
+
+func (pkg *syntaxPackage) AsmFile(uri protocol.DocumentURI) (*asm.File, error) {
+	for _, af := range pkg.asmFiles {
+		if af.URI == uri {
+			return af, nil
+		}	
+	}
+
+	return nil, fmt.Errorf("no parsed file for %s in %v", uri, pkg.id)
+}

gopls/internal/goasm/references.go

@@ -0,0 +1,117 @@
+// Copyright 2025 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 goasm provides language-server features for files in Go
+// assembly language (https://go.dev/doc/asm).
+package goasm
+
+import (
+	"context"
+	"fmt"
+	"go/ast"
+
+	"golang.org/x/tools/gopls/internal/cache"
+	"golang.org/x/tools/gopls/internal/cache/metadata"
+	"golang.org/x/tools/gopls/internal/file"
+	"golang.org/x/tools/gopls/internal/protocol"
+	"golang.org/x/tools/gopls/internal/util/asm"
+	"golang.org/x/tools/gopls/internal/util/morestrings"
+	"golang.org/x/tools/internal/event"
+)
+
+func References(ctx context.Context, snapshot *cache.Snapshot, fh file.Handle, position protocol.Position) ([]protocol.Location, error) {
+	ctx, done := event.Start(ctx, "goasm.References")
+	defer done()
+
+	pkg, asmFile, err := GetPackageID(ctx, snapshot, fh.URI())
+	if err != nil {
+		return nil, err
+	}
+
+	// Read the file.
+	content, err := fh.Content()
+	if err != nil {
+		return nil, err
+	}
+	mapper := protocol.NewMapper(fh.URI(), content)
+	offset, err := mapper.PositionOffset(position)
+	if err != nil {
+		return nil, err
+	}
+
+	// // Parse the assembly.
+	// file := asm.Parse(fh.URI(), content)
+
+	// Figure out the selected symbol.
+	// For now, just find the identifier around the cursor.
+	var found *asm.Ident
+	for _, id := range asmFile.Idents {
+		if id.Offset <= offset && offset <= id.End() {
+			found = &id
+			break
+		}
+	}
+	if found == nil {
+		return nil, fmt.Errorf("not an identifier")
+	}
+
+	sym := found.Name
+	var locations []protocol.Location
+	_, name, ok := morestrings.CutLast(sym, ".")
+	if !ok {
+		return nil, fmt.Errorf("not found")
+	}
+	// return localReferences(pkg, targets, true, report)
+	for _, pgf := range pkg.CompiledGoFiles() {
+		for curId := range pgf.Cursor.Preorder((*ast.Ident)(nil)) {
+			id := curId.Node().(*ast.Ident)
+			if id.Name == name {
+				loc, err := pgf.NodeLocation(id)
+				if err != nil {
+					return nil, err
+				}
+				locations = append(locations, loc)
+			}
+		}
+	}
+
+	for _, asmFile := range pkg.AsmFiles() {
+		for _, id := range asmFile.Idents {
+			if id.Name != sym {
+				continue
+			}
+			if rng, err := asmFile.NodeRange(id); err == nil {
+				asmLocation := protocol.Location{
+					URI:   asmFile.URI,
+					Range: rng,
+				}
+				locations = append(locations, asmLocation)
+			}
+		}
+	}
+
+	return locations, nil
+}
+
+func GetPackageID(ctx context.Context, snapshot *cache.Snapshot, uri protocol.DocumentURI) (*cache.Package, *asm.File, error) {
+	mps, err := snapshot.MetadataForFile(ctx, uri)
+	if err != nil {
+		return nil, nil, err
+	}
+	metadata.RemoveIntermediateTestVariants(&mps)
+	if len(mps) == 0 {
+		return nil, nil, fmt.Errorf("no package metadata for file %s", uri)
+	}
+	mp := mps[0]
+	pkgs, err := snapshot.TypeCheck(ctx, mp.ID)
+	if err != nil {
+		return nil, nil, err
+	}
+	pkg := pkgs[0]
+	asmFile, err := pkg.AsmFile(uri)
+	if err != nil {
+		return nil, nil, err // "can't happen"
+	}
+	return pkg, asmFile, nil
+}

gopls/internal/golang/references.go

@@ -631,7 +631,7 @@ func localReferences(pkg *cache.Package, targets map[types.Object]bool, correspo
 					URI:   pgf.URI,
 					Range: rng,
 				}
-				report(asmLocation, false)
+				report(asmLocation, true)
 			}
 		}
 	}

gopls/internal/server/references.go

@@ -8,6 +8,7 @@ import (
 	"context"
 
 	"golang.org/x/tools/gopls/internal/file"
+	"golang.org/x/tools/gopls/internal/goasm"
 	"golang.org/x/tools/gopls/internal/golang"
 	"golang.org/x/tools/gopls/internal/label"
 	"golang.org/x/tools/gopls/internal/protocol"
@@ -35,6 +36,8 @@ func (s *server) References(ctx context.Context, params *protocol.ReferenceParam
 		return template.References(ctx, snapshot, fh, params)
 	case file.Go:
 		return golang.References(ctx, snapshot, fh, params.Position, params.Context.IncludeDeclaration)
+	case file.Asm:
+		return goasm.References(ctx, snapshot, fh, params.Position)
 	}
 	return nil, nil // empty result
 }