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errors: eliminate all overhead for hidden calls
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Eliminate all overhead for function calls that are to be
hidden from the stack traces at the expense of
reduced performance for the error case

Fixes: nodejs#35386
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@mmomtchev
mmomtchev committed Oct 14, 2020
1 parent 92610f3 commit f8b0124
Showing 1 changed file with 132 additions and 140 deletions.
272 changes: 132 additions & 140 deletions lib/internal/errors.js
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Original file line number Diff line number Diff line change
Expand Up @@ -55,6 +55,7 @@ const kTypes = [
const MainContextError = Error;
const overrideStackTrace = new WeakMap();
const kNoOverride = Symbol('kNoOverride');
let userStackTraceLimit = Error.stackTraceLimit;
const prepareStackTrace = (globalThis, error, trace) => {
// API for node internals to override error stack formatting
// without interfering with userland code.
Expand All @@ -64,6 +65,16 @@ const prepareStackTrace = (globalThis, error, trace) => {
return f(error, trace);
}

for (let l = trace.length - 1; l >= 0; l--) {
const fn = trace[l].getFunctionName();
if (fn != null && fn.startsWith('__node_internal_hidden_')) {
trace.splice(0, l + 1);
break;
}
}
if (trace.length > userStackTraceLimit)
trace.splice(userStackTraceLimit);

const globalOverride =
maybeOverridePrepareStackTrace(globalThis, error, trace);
if (globalOverride !== kNoOverride) return globalOverride;
Expand Down Expand Up @@ -98,8 +109,6 @@ const maybeOverridePrepareStackTrace = (globalThis, error, trace) => {
return kNoOverride;
};

let excludedStackFn;

// Lazily loaded
let util;
let assert;
Expand Down Expand Up @@ -127,6 +136,27 @@ function lazyBuffer() {
return buffer;
}

const addCodeToName = hideStackFrames(function(err, name, code) {
// Set the stack
err = captureLargerStackTrace(err);
// Add the error code to the name to include it in the stack trace.
err.name = `${name} [${code}]`;
// Access the stack to generate the error message including the error code
// from the name.
err.stack;
// Reset the name to the actual name.
if (name === 'SystemError') {
ObjectDefineProperty(err, 'name', {
value: name,
enumerable: false,
writable: true,
configurable: true
});
} else {
delete err.name;
}
});

// A specialized Error that includes an additional info property with
// additional information about the error condition.
// It has the properties present in a UVException but with a custom error
Expand All @@ -137,18 +167,14 @@ function lazyBuffer() {
// and may have .path and .dest.
class SystemError extends Error {
constructor(key, context) {
if (excludedStackFn === undefined) {
super();
} else {
const limit = Error.stackTraceLimit;
Error.stackTraceLimit = 0;
super();
// Reset the limit and setting the name property.
Error.stackTraceLimit = limit;
}
const limit = Error.stackTraceLimit;
Error.stackTraceLimit = 0;
super();
// Reset the limit and setting the name property.
Error.stackTraceLimit = limit;
const prefix = getMessage(key, [], this);
let message = `${prefix}: ${context.syscall} returned ` +
`${context.code} (${context.message})`;
`${context.code} (${context.message})`;

if (context.path !== undefined)
message += ` ${context.path}`;
Expand Down Expand Up @@ -253,16 +279,11 @@ function makeSystemErrorWithCode(key) {

function makeNodeErrorWithCode(Base, key) {
return function NodeError(...args) {
let error;
if (excludedStackFn === undefined) {
error = new Base();
} else {
const limit = Error.stackTraceLimit;
Error.stackTraceLimit = 0;
error = new Base();
// Reset the limit and setting the name property.
Error.stackTraceLimit = limit;
}
const limit = Error.stackTraceLimit;
Error.stackTraceLimit = 0;
const error = new Base();
// Reset the limit and setting the name property.
Error.stackTraceLimit = limit;
const message = getMessage(key, args, error);
ObjectDefineProperty(error, 'message', {
value: message,
Expand All @@ -286,45 +307,9 @@ function makeNodeErrorWithCode(Base, key) {

// This function removes unnecessary frames from Node.js core errors.
function hideStackFrames(fn) {
return function hidden(...args) {
// Make sure the most outer `hideStackFrames()` function is used.
let setStackFn = false;
if (excludedStackFn === undefined) {
excludedStackFn = hidden;
setStackFn = true;
}
try {
return fn(...args);
} finally {
if (setStackFn === true) {
excludedStackFn = undefined;
}
}
};
}

function addCodeToName(err, name, code) {
// Set the stack
if (excludedStackFn !== undefined) {
// eslint-disable-next-line no-restricted-syntax
Error.captureStackTrace(err, excludedStackFn);
}
// Add the error code to the name to include it in the stack trace.
err.name = `${name} [${code}]`;
// Access the stack to generate the error message including the error code
// from the name.
err.stack;
// Reset the name to the actual name.
if (name === 'SystemError') {
ObjectDefineProperty(err, 'name', {
value: name,
enumerable: false,
writable: true,
configurable: true
});
} else {
delete err.name;
}
const hidden = '__node_internal_hidden_' + fn.name;
ObjectDefineProperty(fn, 'name', { value: hidden });
return fn;
}

// Utility function for registering the error codes. Only used here. Exported
Expand Down Expand Up @@ -393,6 +378,16 @@ function uvErrmapGet(name) {
return uvBinding.errmap.get(name);
}

function captureLargerStackTrace(err) {
userStackTraceLimit = Error.stackTraceLimit;
Error.stackTraceLimit = 20;
// eslint-disable-next-line no-restricted-syntax
Error.captureStackTrace(err);
// Reset the limit and setting the name property.
Error.stackTraceLimit = userStackTraceLimit;

return err;
}

/**
* This creates an error compatible with errors produced in the C++
Expand All @@ -403,8 +398,8 @@ function uvErrmapGet(name) {
* @param {Object} ctx
* @returns {Error}
*/
function uvException(ctx) {
const [ code, uvmsg ] = uvErrmapGet(ctx.errno) || uvUnmappedError;
const uvException = hideStackFrames(function(ctx) {
const [code, uvmsg] = uvErrmapGet(ctx.errno) || uvUnmappedError;
let message = `${code}: ${ctx.message || uvmsg}, ${ctx.syscall}`;

let path;
Expand Down Expand Up @@ -444,10 +439,8 @@ function uvException(ctx) {
err.dest = dest;
}

// eslint-disable-next-line no-restricted-syntax
Error.captureStackTrace(err, excludedStackFn || uvException);
return err;
}
return captureLargerStackTrace(err);
});

/**
* This creates an error compatible with errors produced in the C++
Expand All @@ -460,37 +453,37 @@ function uvException(ctx) {
* @param {number} [port]
* @returns {Error}
*/
function uvExceptionWithHostPort(err, syscall, address, port) {
const [ code, uvmsg ] = uvErrmapGet(err) || uvUnmappedError;
const message = `${syscall} ${code}: ${uvmsg}`;
let details = '';

if (port && port > 0) {
details = ` ${address}:${port}`;
} else if (address) {
details = ` ${address}`;
}
const uvExceptionWithHostPort =
hideStackFrames(function(err, syscall, address, port) {
const [code, uvmsg] = uvErrmapGet(err) || uvUnmappedError;
const message = `${syscall} ${code}: ${uvmsg}`;
let details = '';

if (port && port > 0) {
details = ` ${address}:${port}`;
} else if (address) {
details = ` ${address}`;
}

// Reducing the limit improves the performance significantly. We do not loose
// the stack frames due to the `captureStackTrace()` function that is called
// later.
const tmpLimit = Error.stackTraceLimit;
Error.stackTraceLimit = 0;
// eslint-disable-next-line no-restricted-syntax
const ex = new Error(`${message}${details}`);
Error.stackTraceLimit = tmpLimit;
ex.code = code;
ex.errno = err;
ex.syscall = syscall;
ex.address = address;
if (port) {
ex.port = port;
}
// Reducing the limit improves the performance significantly. We do not
// loose the stack frames due to the `captureStackTrace()` function that
// is called later.
const tmpLimit = Error.stackTraceLimit;
Error.stackTraceLimit = 0;
// eslint-disable-next-line no-restricted-syntax
const ex = new Error(`${message}${details}`);
Error.stackTraceLimit = tmpLimit;
ex.code = code;
ex.errno = err;
ex.syscall = syscall;
ex.address = address;
if (port) {
ex.port = port;
}

// eslint-disable-next-line no-restricted-syntax
Error.captureStackTrace(ex, excludedStackFn || uvExceptionWithHostPort);
return ex;
}
captureLargerStackTrace(ex);
return ex;
});

/**
* This used to be util._errnoException().
Expand All @@ -500,7 +493,7 @@ function uvExceptionWithHostPort(err, syscall, address, port) {
* @param {string} [original]
* @returns {Error}
*/
function errnoException(err, syscall, original) {
const errnoException = hideStackFrames(function(err, syscall, original) {
// TODO(joyeecheung): We have to use the type-checked
// getSystemErrorName(err) to guard against invalid arguments from users.
// This can be replaced with [ code ] = errmap.get(err) when this method
Expand All @@ -510,16 +503,18 @@ function errnoException(err, syscall, original) {
const message = original ?
`${syscall} ${code} ${original}` : `${syscall} ${code}`;

const tmpLimit = Error.stackTraceLimit;
Error.stackTraceLimit = 0;
// eslint-disable-next-line no-restricted-syntax
const ex = new Error(message);
Error.stackTraceLimit = tmpLimit;
ex.errno = err;
ex.code = code;
ex.syscall = syscall;

// eslint-disable-next-line no-restricted-syntax
Error.captureStackTrace(ex, excludedStackFn || errnoException);
captureLargerStackTrace(ex);
return ex;
}
});

/**
* Deprecated, new function is `uvExceptionWithHostPort()`
Expand All @@ -532,51 +527,50 @@ function errnoException(err, syscall, original) {
* @param {string} [additional]
* @returns {Error}
*/
function exceptionWithHostPort(err, syscall, address, port, additional) {
// TODO(joyeecheung): We have to use the type-checked
// getSystemErrorName(err) to guard against invalid arguments from users.
// This can be replaced with [ code ] = errmap.get(err) when this method
// is no longer exposed to user land.
if (util === undefined) util = require('util');
const code = util.getSystemErrorName(err);
let details = '';
if (port && port > 0) {
details = ` ${address}:${port}`;
} else if (address) {
details = ` ${address}`;
}
if (additional) {
details += ` - Local (${additional})`;
}
const exceptionWithHostPort =
hideStackFrames(function(err, syscall, address, port, additional) {
// TODO(joyeecheung): We have to use the type-checked
// getSystemErrorName(err) to guard against invalid arguments from users.
// This can be replaced with [ code ] = errmap.get(err) when this method
// is no longer exposed to user land.
if (util === undefined) util = require('util');
const code = util.getSystemErrorName(err);
let details = '';
if (port && port > 0) {
details = ` ${address}:${port}`;
} else if (address) {
details = ` ${address}`;
}
if (additional) {
details += ` - Local (${additional})`;
}

// Reducing the limit improves the performance significantly. We do not loose
// the stack frames due to the `captureStackTrace()` function that is called
// later.
const tmpLimit = Error.stackTraceLimit;
Error.stackTraceLimit = 0;
// eslint-disable-next-line no-restricted-syntax
const ex = new Error(`${syscall} ${code}${details}`);
Error.stackTraceLimit = tmpLimit;
ex.errno = err;
ex.code = code;
ex.syscall = syscall;
ex.address = address;
if (port) {
ex.port = port;
}
// Reducing the limit improves the performance significantly. We do not
// loose the stack frames due to the `captureStackTrace()` function that
// is called later.
const tmpLimit = Error.stackTraceLimit;
Error.stackTraceLimit = 0;
// eslint-disable-next-line no-restricted-syntax
const ex = new Error(`${syscall} ${code}${details}`);
Error.stackTraceLimit = tmpLimit;
ex.errno = err;
ex.code = code;
ex.syscall = syscall;
ex.address = address;
if (port) {
ex.port = port;
}

// eslint-disable-next-line no-restricted-syntax
Error.captureStackTrace(ex, excludedStackFn || exceptionWithHostPort);
return ex;
}
return captureLargerStackTrace(ex);
});

/**
* @param {number|string} code - A libuv error number or a c-ares error code
* @param {string} syscall
* @param {string} [hostname]
* @returns {Error}
*/
function dnsException(code, syscall, hostname) {
const dnsException = hideStackFrames(function(code, syscall, hostname) {
let errno;
// If `code` is of type number, it is a libuv error number, else it is a
// c-ares error code.
Expand Down Expand Up @@ -611,10 +605,8 @@ function dnsException(code, syscall, hostname) {
ex.hostname = hostname;
}

// eslint-disable-next-line no-restricted-syntax
Error.captureStackTrace(ex, excludedStackFn || dnsException);
return ex;
}
return captureLargerStackTrace(ex);
});

function connResetException(msg) {
// eslint-disable-next-line no-restricted-syntax
Expand Down

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