From ff0a91422a2fed4764e3f96eabf7be0ef049a88b Mon Sep 17 00:00:00 2001
From: JoostK <joost.koehoorn@gmail.com>
Date: Sun, 8 Dec 2019 20:37:45 +0100
Subject: [PATCH] perf(compiler): speed up i18n digest computations (#34332)

Avoids the usage of array destructuring, as it introduces calls to
a `__values` helper function in ES5 that has a relatively high
performance impact. This shaves off roughly 130ms of CPU time for a
large compilation with big templates that uses i18n.

PR Close #34332
---
 packages/compiler/src/i18n/digest.ts | 53 +++++++++++++++++++---------
 1 file changed, 36 insertions(+), 17 deletions(-)

diff --git a/packages/compiler/src/i18n/digest.ts b/packages/compiler/src/i18n/digest.ts
index eec617a81b..e81a26e6a1 100644
--- a/packages/compiler/src/i18n/digest.ts
+++ b/packages/compiler/src/i18n/digest.ts
@@ -110,13 +110,13 @@ export function sha1(str: string): string {
   const len = utf8.length * 8;
 
   const w = newArray(80);
-  let [a, b, c, d, e]: number[] = [0x67452301, 0xefcdab89, 0x98badcfe, 0x10325476, 0xc3d2e1f0];
+  let a = 0x67452301, b = 0xefcdab89, c = 0x98badcfe, d = 0x10325476, e = 0xc3d2e1f0;
 
   words32[len >> 5] |= 0x80 << (24 - len % 32);
   words32[((len + 64 >> 9) << 4) + 15] = len;
 
   for (let i = 0; i < words32.length; i += 16) {
-    const [h0, h1, h2, h3, h4]: number[] = [a, b, c, d, e];
+    const h0 = a, h1 = b, h2 = c, h3 = d, h4 = e;
 
     for (let j = 0; j < 80; j++) {
       if (j < 16) {
@@ -125,12 +125,21 @@ export function sha1(str: string): string {
         w[j] = rol32(w[j - 3] ^ w[j - 8] ^ w[j - 14] ^ w[j - 16], 1);
       }
 
-      const [f, k] = fk(j, b, c, d);
+      const fkVal = fk(j, b, c, d);
+      const f = fkVal[0];
+      const k = fkVal[1];
       const temp = [rol32(a, 5), f, e, k, w[j]].reduce(add32);
-      [e, d, c, b, a] = [d, c, rol32(b, 30), a, temp];
+      e = d;
+      d = c;
+      c = rol32(b, 30);
+      b = a;
+      a = temp;
     }
-
-    [a, b, c, d, e] = [add32(a, h0), add32(b, h1), add32(c, h2), add32(d, h3), add32(e, h4)];
+    a = add32(a, h0);
+    b = add32(b, h1);
+    c = add32(c, h2);
+    d = add32(d, h3);
+    e = add32(e, h4);
   }
 
   return byteStringToHexString(words32ToByteString([a, b, c, d, e]));
@@ -163,7 +172,8 @@ function fk(index: number, b: number, c: number, d: number): [number, number] {
 export function fingerprint(str: string): [number, number] {
   const utf8 = utf8Encode(str);
 
-  let [hi, lo] = [hash32(utf8, 0), hash32(utf8, 102072)];
+  let hi = hash32(utf8, 0);
+  let lo = hash32(utf8, 102072);
 
   if (hi == 0 && (lo == 0 || lo == 1)) {
     hi = hi ^ 0x130f9bef;
@@ -174,18 +184,21 @@ export function fingerprint(str: string): [number, number] {
 }
 
 export function computeMsgId(msg: string, meaning: string = ''): string {
-  let [hi, lo] = fingerprint(msg);
+  let msgFingerprint = fingerprint(msg);
 
   if (meaning) {
-    const [him, lom] = fingerprint(meaning);
-    [hi, lo] = add64(rol64([hi, lo], 1), [him, lom]);
+    const meaningFingerprint = fingerprint(meaning);
+    msgFingerprint = add64(rol64(msgFingerprint, 1), meaningFingerprint);
   }
 
+  const hi = msgFingerprint[0];
+  const lo = msgFingerprint[1];
+
   return byteStringToDecString(words32ToByteString([hi & 0x7fffffff, lo]));
 }
 
 function hash32(str: string, c: number): number {
-  let [a, b] = [0x9e3779b9, 0x9e3779b9];
+  let a = 0x9e3779b9, b = 0x9e3779b9;
   let i: number;
 
   const len = str.length;
@@ -194,7 +207,8 @@ function hash32(str: string, c: number): number {
     a = add32(a, wordAt(str, i, Endian.Little));
     b = add32(b, wordAt(str, i + 4, Endian.Little));
     c = add32(c, wordAt(str, i + 8, Endian.Little));
-    [a, b, c] = mix([a, b, c]);
+    const res = mix(a, b, c);
+    a = res[0], b = res[1], c = res[2];
   }
 
   a = add32(a, wordAt(str, i, Endian.Little));
@@ -203,11 +217,11 @@ function hash32(str: string, c: number): number {
   c = add32(c, len);
   c = add32(c, wordAt(str, i + 8, Endian.Little) << 8);
 
-  return mix([a, b, c])[2];
+  return mix(a, b, c)[2];
 }
 
 // clang-format off
-function mix([a, b, c]: [number, number, number]): [number, number, number] {
+function mix(a: number, b: number, c: number): [number, number, number] {
   a = sub32(a, b); a = sub32(a, c); a ^= c >>> 13;
   b = sub32(b, c); b = sub32(b, a); b ^= a << 8;
   c = sub32(c, a); c = sub32(c, b); c ^= b >>> 13;
@@ -238,8 +252,12 @@ function add32to64(a: number, b: number): [number, number] {
   return [high >>> 16, (high << 16) | (low & 0xffff)];
 }
 
-function add64([ah, al]: [number, number], [bh, bl]: [number, number]): [number, number] {
-  const [carry, l] = add32to64(al, bl);
+function add64(a: [number, number], b: [number, number]): [number, number] {
+  const ah = a[0], al = a[1];
+  const bh = b[0], bl = b[1];
+  const result = add32to64(al, bl);
+  const carry = result[0];
+  const l = result[1];
   const h = add32(add32(ah, bh), carry);
   return [h, l];
 }
@@ -256,7 +274,8 @@ function rol32(a: number, count: number): number {
 }
 
 // Rotate a 64b number left `count` position
-function rol64([hi, lo]: [number, number], count: number): [number, number] {
+function rol64(num: [number, number], count: number): [number, number] {
+  const hi = num[0], lo = num[1];
   const h = (hi << count) | (lo >>> (32 - count));
   const l = (lo << count) | (hi >>> (32 - count));
   return [h, l];