Remove previous node.js labels approach

We are replacing the manually propagated hashmap-based approach with
an approach based on stuffing the labels in v8's
ContinuationPreservedEmbedderData (see upcoming commit).

Author: umanwizard

interpreter/customlabels/customlabels.go

@@ -16,19 +16,14 @@ import (
 const (
 	abiVersionExport    = "custom_labels_abi_version"
 	currentSetTlsExport = "custom_labels_current_set"
-	currentHmTlsExport  = "custom_labels_async_hashmap"
 )
 
 var dsoRegex = regexp.MustCompile(`.*/libcustomlabels.*\.so`)
-var nodeRegex = regexp.MustCompile(`.*/customlabels\.node`)
 
 type data struct {
 	abiVersionElfVA   libpf.Address
 	currentSetTlsAddr libpf.Address
 
-	hasCurrentHm     bool
-	currentHmTlsAddr libpf.Address
-
 	isSharedLibrary bool
 }
 
@@ -58,12 +53,9 @@ func Loader(_ interpreter.EbpfHandler, info *interpreter.LoaderInfo) (interprete
 	// symbol.
 	fn := info.FileName()
 	isNativeSharedLibrary := dsoRegex.MatchString(fn)
-	isNodeExtension := (!isNativeSharedLibrary) && nodeRegex.MatchString(fn)
-	isSharedLibrary := isNativeSharedLibrary || isNodeExtension
 
-	var currentSetTlsAddr, currentHmTlsAddr libpf.Address
-	var hasCurrentHm bool
-	if isSharedLibrary {
+	var currentSetTlsAddr libpf.Address
+	if isNativeSharedLibrary {
 		// Resolve thread info TLS export.
 		tlsDescs, err := ef.TLSDescriptors()
 		if err != nil {
@@ -74,9 +66,6 @@ func Loader(_ interpreter.EbpfHandler, info *interpreter.LoaderInfo) (interprete
 		if !ok {
 			return nil, errors.New("failed to locate TLS descriptor for custom labels")
 		}
-		if isNodeExtension {
-			currentHmTlsAddr, hasCurrentHm = tlsDescs[currentHmTlsExport]
-		}
 	} else {
 		offset, err := ef.LookupTLSSymbolOffset(currentSetTlsExport)
 		if err != nil {
@@ -88,9 +77,7 @@ func Loader(_ interpreter.EbpfHandler, info *interpreter.LoaderInfo) (interprete
 	d := data{
 		abiVersionElfVA:   libpf.Address(abiVersionSym.Address),
 		currentSetTlsAddr: currentSetTlsAddr,
-		hasCurrentHm:      hasCurrentHm,
-		currentHmTlsAddr:  currentHmTlsAddr,
-		isSharedLibrary:   isSharedLibrary,
+		isSharedLibrary:   isNativeSharedLibrary,
 	}
 	return &d, nil
 }
@@ -120,15 +107,8 @@ func (d data) Attach(ebpf interpreter.EbpfHandler, pid libpf.PID,
 		currentSetTlsOffset = uint64(d.currentSetTlsAddr)
 	}
 
-	var currentHmTlsOffset uint64
-	if d.hasCurrentHm {
-		currentHmTlsOffset = rm.Uint64(bias + d.currentHmTlsAddr + 8)
-	}
-
 	procInfo := support.NativeCustomLabelsProcInfo{
-		Current_set_tls_offset: currentSetTlsOffset,
-		Has_current_hm:         d.hasCurrentHm,
-		Current_hm_tls_offset:  currentHmTlsOffset,
+		Set_tls_offset: currentSetTlsOffset,
 	}
 	if err := ebpf.UpdateProcData(libpf.CustomLabels, pid, unsafe.Pointer(&procInfo)); err != nil {
 		return nil, err

interpreter/nodev8/node_offsets_generated.go

@@ -1,5 +1,3 @@
-//go:generate go run ../../tools/csv2go.go ../../tools/complete_offsets.csv node_offsets_generated.go
-
 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0
 
@@ -156,7 +154,6 @@ package nodev8 // import "go.opentelemetry.io/ebpf-profiler/interpreter/nodev8"
 
 import (
 	"bytes"
-	"encoding/binary"
 	"errors"
 	"fmt"
 	"io"
@@ -475,13 +472,6 @@ type v8Data struct {
 	// version contains the V8 version
 	version uint32
 
-	// Node.js environment offsets
-	contextHandleOffset      uint32
-	nativeContextOffset      uint32
-	embedderDataOffset       uint32
-	environmentPointerOffset uint32
-	executionAsyncIdOffset   uint32
-
 	// bytecodeSizes contains the V8 bytecode length data
 	bytecodeSizes []byte
 
@@ -490,9 +480,6 @@ type v8Data struct {
 
 	// frametypeToName caches frametype's name
 	frametypeToName [MaxFrameType]libpf.String
-
-	// isolateSym is the symbol of the v8 thread-local current isolate
-	isolateSym libpf.Address
 }
 
 type v8Instance struct {
@@ -1774,12 +1761,6 @@ func (d *v8Data) Attach(ebpf interpreter.EbpfHandler, pid libpf.PID, _ libpf.Add
 	data := support.V8ProcInfo{
 		Version: d.version,
 
-		Context_handle_offset:      d.contextHandleOffset,
-		Native_context_offset:      d.nativeContextOffset,
-		Embedder_data_offset:       d.embedderDataOffset,
-		Environment_pointer_offset: d.environmentPointerOffset,
-		Execution_async_id_offset:  d.executionAsyncIdOffset,
-
 		Fp_marker:          mapFramePointerOffset(vms.FramePointer.Context),
 		Fp_function:        mapFramePointerOffset(vms.FramePointer.Function),
 		Fp_bytecode_offset: mapFramePointerOffset(vms.FramePointer.BytecodeOffset),
@@ -1798,10 +1779,9 @@ func (d *v8Data) Attach(ebpf interpreter.EbpfHandler, pid libpf.PID, _ libpf.Add
 		Off_Code_instruction_size:  uint8(vms.Code.InstructionSize),
 		Off_Code_flags:             uint8(vms.Code.Flags),
 
-		Codekind_shift:    vms.CodeKind.FieldShift,
-		Codekind_mask:     uint8(vms.CodeKind.FieldMask),
-		Codekind_baseline: vms.CodeKind.Baseline,
-		Isolate_sym:       uint64(d.isolateSym),
+		Codekind_shift:        vms.CodeKind.FieldShift,
+		Codekind_mask:         uint8(vms.CodeKind.FieldMask),
+		Codekind_baseline:     vms.CodeKind.Baseline,
 	}
 	if err := ebpf.UpdateProcData(libpf.V8, pid, unsafe.Pointer(&data)); err != nil {
 		return nil, err
@@ -2099,56 +2079,6 @@ func (d *v8Data) readIntrospectionData(ef *pfelf.File) error {
 	return nil
 }
 
-// loadNodeClData loads various offsets that are needed for custom labels handling.
-func (d *v8Data) loadNodeClData(ef *pfelf.File) error {
-	offset, err := ef.LookupTLSSymbolOffset("_ZN2v88internal18g_current_isolate_E")
-	if err != nil {
-		return err
-	}
-	d.isolateSym = libpf.Address(offset)
-
-	syms, err := ef.ReadSymbols()
-	if err != nil {
-		return fmt.Errorf("failed to read symbols: %w", err)
-	}
-
-	sym, err := syms.LookupSymbol("_ZZ21napi_get_node_versionE7version")
-	if err != nil {
-		return fmt.Errorf("failed to lookup Node version symbol: %w", err)
-	}
-
-	if sym == nil {
-		return errors.New("Node version symbol not found")
-	}
-
-	if sym.Size < 12 {
-		return fmt.Errorf("Node version symbol size too small: %d", sym.Size)
-	}
-
-	versBuf := make([]byte, 12)
-	if _, err = ef.ReadVirtualMemory(versBuf, int64(sym.Address)); err != nil {
-		return fmt.Errorf("failed to read Node version data: %w", err)
-	}
-
-	major := binary.LittleEndian.Uint32(versBuf[0:4])
-	minor := binary.LittleEndian.Uint32(versBuf[4:8])
-	patch := binary.LittleEndian.Uint32(versBuf[8:12])
-
-	// Construct version string and look up Node.js environment offsets
-	nodeVersion := fmt.Sprintf("v%d.%d.%d", major, minor, patch)
-	if offsets, found := nodeOffsetTable[nodeVersion]; found {
-		d.contextHandleOffset = offsets.contextHandle
-		d.nativeContextOffset = offsets.nativeContext
-		d.embedderDataOffset = offsets.embedderData
-		d.environmentPointerOffset = offsets.environmentPointer
-		d.executionAsyncIdOffset = offsets.executionAsyncId
-	} else {
-		return fmt.Errorf("no offsets found for Node.js version %s", nodeVersion)
-	}
-
-	return nil
-}
-
 func Loader(ebpf interpreter.EbpfHandler, info *interpreter.LoaderInfo) (interpreter.Data, error) {
 	if !v8Regex.MatchString(info.FileName()) {
 		return nil, nil
@@ -2217,10 +2147,6 @@ func Loader(ebpf interpreter.EbpfHandler, info *interpreter.LoaderInfo) (interpr
 		}
 	}
 
-	if err = d.loadNodeClData(ef); err != nil {
-		log.Warnf("Failed to load extra data for Node.js custom labels handling: %v", err)
-	}
-
 	// load introspection data
 	if err = d.readIntrospectionData(ef); err != nil {
 		return nil, err