perf(gnovm): cache PkgIDFromPkgPath for higher performance

gnovm/pkg/gnolang/bench_test.go

@@ -0,0 +1,31 @@
+package gnolang
+
+import (
+	"testing"
+)
+
+var sink any = nil
+
+var pkgIDPaths = []string{
+	"encoding/json",
+	"math/bits",
+	"github.com/gnolang/gno/gnovm/pkg/gnolang",
+	"a",
+	" ",
+	"",
+	"github.com/gnolang/gno/gnovm/pkg/gnolang/vendor/pkg/github.com/gnolang/vendored",
+}
+
+func BenchmarkPkgIDFromPkgPath(b *testing.B) {
+	b.ReportAllocs()
+	for i := 0; i < b.N; i++ {
+		for _, path := range pkgIDPaths {
+			sink = PkgIDFromPkgPath(path)
+		}
+	}
+
+	if sink == nil {
+		b.Fatal("Benchmark did not run!")
+	}
+	sink = nil
+}

gnovm/pkg/gnolang/realm.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"reflect"
 	"strings"
+	"sync"
 
 	bm "github.com/gnolang/gno/gnovm/pkg/benchops"
 )
@@ -71,8 +72,25 @@ func (pid PkgID) Bytes() []byte {
 	return pid.Hashlet[:]
 }
 
+var (
+	pkgIDMu sync.Mutex // pkgIDMu protects the shared cache.
+	// TODO: later on switch this to an LRU if needed to ensure
+	// fixed memory caps. For now though it isn't a problem:
+	// https://github.com/gnolang/gno/pull/3424#issuecomment-2564571785
+	pkgIDFromPkgPathCache = make(map[string]*PkgID, 100)
+)
+
 func PkgIDFromPkgPath(path string) PkgID {
-	return PkgID{HashBytes([]byte(path))}
+	pkgIDMu.Lock()
+	defer pkgIDMu.Unlock()
+
+	pkgID, ok := pkgIDFromPkgPathCache[path]
+	if !ok {
+		pkgID = new(PkgID)
+		*pkgID = PkgID{HashBytes([]byte(path))}
+		pkgIDFromPkgPathCache[path] = pkgID
+	}
+	return *pkgID
 }
 
 // Returns the ObjectID of the PackageValue associated with path.