mmarchini

# Uncomment deb-src lines on /etc/apt/sources.list
sudo apt-get update

# Or replace ~/glibc with preferred path to store libc source
mkdir -p ~/glibc
cd ~/glibc

sudo apt-get install -y dpkg-dev
sudo apt-get build-deps libc6
apt-get source libc6

mmarchini

// Node v10.15.3
uprobe:/home/mmarchini/.nvm/versions/node/v10.15.3/bin/node:_ZN2v88internal17Builtin_JsonParseEiPPNS0_6ObjectEPNS0_7IsolateE
{
  // Load constants
  $kPointerSize = (uint32)(1 << (*uaddr("v8dbg_PointerSizeLog2")));
  $stringLengthOffset = (uint32)*uaddr("v8dbg_class_String__length__SMI");
  $kTag = (uint32)*uaddr("v8dbg_HeapObjectTag");
  $kTagMask = (uint32)*uaddr("v8dbg_SmiTagMask");
  $kShiftSize = (uint32)*uaddr("v8dbg_SmiShiftSize");

mmarchini

$ make LDFLAGS=-static NO_PERF_READ_VDSO32=1 NO_PERF_READ_VDSOX32=1 NO_JVMTI=1
  BUILD:   Doing 'make -j8' parallel build
  HOSTCC   fixdep.o
  HOSTLD   fixdep-in.o
  LINK     fixdep

Auto-detecting system features:
...                         dwarf: [ on  ]
...            dwarf_getlocations: [ on  ]
...                         glibc: [ on  ]

mmarchini

(lldb) target create "/home/mmarchini/.nvm/versions/node/v12.3.0/bin/node" --core "core.frame-scenario.1"
Core file '/home/mmarchini/workspace/nodejs/llnode/core.frame-scenario.1' (x86_64) was loaded.
(lldb) plugin load '/home/mmarchini/workspace/nodejs/llnode/llnode.so'
(lldb) settings set prompt '(llnode) '
(llnode) command script import diagnose_unwind
bind: Invalid command `enable-meta-key'.
The "diagnose-unwind" command has been installed, type "help diagnose-unwind" for detailed help.
(llnode) diagnose-unwind
LLDB version lldb version 6.0.1
Unwind diagnostics for thread 1

mmarchini

Goals

When a promise is rejected with no catch handler attached, it should:

• Aborting with error code for unhandled rejection to generate core-dump
• Get stack trace from the point where the error was thrown
• Inspecting arguments, closures and variables

Current State

mmarchini

#include <v8.h>
#include <v8-postmortem.h>
#include <napi.h>
#include <lldb/API/SBDebugger.h>
#include <lldb/API/SBTarget.h>
#include <lldb/API/SBProcess.h>

#include <iostream>

using lldb::addr_t;

mmarchini

'use strict';

const http = require('http');
const port = 3000;

class Visit {
  constructor(visit_id, headers) {
    this.visit_id = visit_id;
    this.headers = headers;
  }

mmarchini

#!/usr/bin/env zsh

local LAMBDA="%(?,%{$fg_bold[green]%}λ,%{$fg_bold[red]%}λ)"

function get_pwd(){
  git_root=$PWD
  while [[ $git_root != / && ! -e $git_root/.git ]]; do
    git_root=$git_root:h
  done
  if [[ $git_root = / ]]; then

mmarchini

$ node benchmark/compare.js --old ./node-master --new ./node-hack-the-stack http > compare-hack-the-stack.http.csv
$ cat compare-hack-the-stack.http.csv  | Rscript benchmark/compare.R
                                                                                                confidence improvement accuracy (*)    (**)   (***)
 http/bench-parser.js n=100000 len=16                                                                          -1.17 %       ±3.73%  ±4.96%  ±6.46%
 http/bench-parser.js n=100000 len=32                                                                          -1.55 %       ±3.19%  ±4.24%  ±5.52%
 http/bench-parser.js n=100000 len=4                                                                           -2.90 %       ±4.20%  ±5.59%  ±7.27%
 http/bench-parser.js n=100000 len=8                                                                           -2.39 %       ±3.41%  ±4.54%  ±5.91%
 http/check_invalid_header_char.js n=1000000 input=''                                       

mmarchini

v8-version,6,1,534,48,0
shared-library,"/usr/bin/node",0x00400000,0x01fa2000,0
shared-library,"/lib/x86_64-linux-gnu/libc-2.26.so",0x7f8a84f0c000,0x7f8a850e2000,0
shared-library,"/lib/x86_64-linux-gnu/libpthread-2.26.so",0x7f8a852ec000,0x7f8a85306000,0
shared-library,"/lib/x86_64-linux-gnu/libgcc_s.so.1",0x7f8a8550b000,0x7f8a85521000,0
shared-library,"/lib/x86_64-linux-gnu/libm-2.26.so",0x7f8a85722000,0x7f8a85877000,0
shared-library,"/usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.24",0x7f8a85a78000,0x7f8a85bf0000,0
shared-library,"/lib/x86_64-linux-gnu/librt-2.26.so",0x7f8a85dfe000,0x7f8a85e05000,0
shared-library,"/lib/x86_64-linux-gnu/libdl-2.26.so",0x7f8a86006000,0x7f8a86009000,0
shared-library,"/lib/x86_64-linux-gnu/ld-2.26.so",0x7f8a8620a000,0x7f8a86231000,0