btf: Optimizing BTF parsing by merging readTypes and inflateRawTypes

btf/btf.go

@@ -209,12 +209,7 @@ func loadRawSpec(btf io.ReaderAt, bo binary.ByteOrder, base *Spec) (*Spec, error
 		}
 	}
 
-	rawTypes, rawStrings, err := parseBTF(btf, bo, baseStrings)
-	if err != nil {
-		return nil, err
-	}
-
-	types, err := inflateRawTypes(rawTypes, rawStrings, base)
+	types, rawStrings, err := parseBTF(btf, bo, baseStrings, base)
 	if err != nil {
 		return nil, err
 	}
@@ -373,7 +368,7 @@ func guessRawBTFByteOrder(r io.ReaderAt) binary.ByteOrder {
 
 // parseBTF reads a .BTF section into memory and parses it into a list of
 // raw types and a string table.
-func parseBTF(btf io.ReaderAt, bo binary.ByteOrder, baseStrings *stringTable) ([]rawType, *stringTable, error) {
+func parseBTF(btf io.ReaderAt, bo binary.ByteOrder, baseStrings *stringTable, base *Spec) ([]Type, *stringTable, error) {
 	buf := internal.NewBufferedSectionReader(btf, 0, math.MaxInt64)
 	header, err := parseBTFHeader(buf, bo)
 	if err != nil {
@@ -387,12 +382,12 @@ func parseBTF(btf io.ReaderAt, bo binary.ByteOrder, baseStrings *stringTable) ([
 	}
 
 	buf.Reset(io.NewSectionReader(btf, header.typeStart(), int64(header.TypeLen)))
-	rawTypes, err := readTypes(buf, bo, header.TypeLen)
+	types, err := readAndInflateTypes(buf, bo, header.TypeLen, rawStrings, base)
 	if err != nil {
-		return nil, nil, fmt.Errorf("can't read types: %w", err)
+		return nil, nil, err
 	}
 
-	return rawTypes, rawStrings, nil
+	return types, rawStrings, nil
 }
 
 type symbol struct {

btf/btf_types.go

@@ -365,67 +365,3 @@ type btfParam struct {
 type btfDeclTag struct {
 	ComponentIdx uint32
 }
-
-func readTypes(r io.Reader, bo binary.ByteOrder, typeLen uint32) ([]rawType, error) {
-	var header btfType
-	// because of the interleaving between types and struct members it is difficult to
-	// precompute the numbers of raw types this will parse
-	// this "guess" is a good first estimation
-	sizeOfbtfType := uintptr(btfTypeLen)
-	tyMaxCount := uintptr(typeLen) / sizeOfbtfType / 2
-	types := make([]rawType, 0, tyMaxCount)
-
-	for id := TypeID(1); ; id++ {
-		if err := binary.Read(r, bo, &header); err == io.EOF {
-			return types, nil
-		} else if err != nil {
-			return nil, fmt.Errorf("can't read type info for id %v: %v", id, err)
-		}
-
-		var data interface{}
-		switch header.Kind() {
-		case kindInt:
-			data = new(btfInt)
-		case kindPointer:
-		case kindArray:
-			data = new(btfArray)
-		case kindStruct:
-			fallthrough
-		case kindUnion:
-			data = make([]btfMember, header.Vlen())
-		case kindEnum:
-			data = make([]btfEnum, header.Vlen())
-		case kindForward:
-		case kindTypedef:
-		case kindVolatile:
-		case kindConst:
-		case kindRestrict:
-		case kindFunc:
-		case kindFuncProto:
-			data = make([]btfParam, header.Vlen())
-		case kindVar:
-			data = new(btfVariable)
-		case kindDatasec:
-			data = make([]btfVarSecinfo, header.Vlen())
-		case kindFloat:
-		case kindDeclTag:
-			data = new(btfDeclTag)
-		case kindTypeTag:
-		case kindEnum64:
-			data = make([]btfEnum64, header.Vlen())
-		default:
-			return nil, fmt.Errorf("type id %v: unknown kind: %v", id, header.Kind())
-		}
-
-		if data == nil {
-			types = append(types, rawType{header, nil})
-			continue
-		}
-
-		if err := binary.Read(r, bo, data); err != nil {
-			return nil, fmt.Errorf("type id %d: kind %v: can't read %T: %v", id, header.Kind(), data, err)
-		}
-
-		types = append(types, rawType{header, data})
-	}
-}