From df759cbe98a661a601cdc86fbb5000f33bcc3b21 Mon Sep 17 00:00:00 2001
From: Ingvar Stepanyan <rreverser@google.com>
Date: Wed, 18 Sep 2019 14:48:54 +0100
Subject: [PATCH] Add support for V8 intrinsics via Babel

This plugin was recently added on Babel side and allows to parse custom syntax for V8 intrinsics.

They don't clash with any real-world JavaScript syntax, so adding this option should be as safe as any other plugin, and would allow to format JavaScript that uses such intrinsics (e.g. code inside Node.js or V8 itself).
---
 CHANGELOG.unreleased.md                       | 25 ++++++++++
 src/language-js/parser-babylon.js             |  3 +-
 src/language-js/printer-estree.js             |  2 +
 .../__snapshots__/jsfmt.spec.js.snap          | 47 +++++++++++++++++++
 tests/v8_intrinsic/intrinsic_call.js          | 24 ++++++++++
 tests/v8_intrinsic/jsfmt.spec.js              |  1 +
 6 files changed, 101 insertions(+), 1 deletion(-)
 create mode 100644 tests/v8_intrinsic/__snapshots__/jsfmt.spec.js.snap
 create mode 100644 tests/v8_intrinsic/intrinsic_call.js
 create mode 100644 tests/v8_intrinsic/jsfmt.spec.js

diff --git a/CHANGELOG.unreleased.md b/CHANGELOG.unreleased.md
index 71254804df64..4e84dc429c58 100644
--- a/CHANGELOG.unreleased.md
+++ b/CHANGELOG.unreleased.md
@@ -836,6 +836,29 @@ type C = (number | string)["toString"];
 type D = (keyof T1)["foo"];
 ```
 
+#### JavaScript: Support formatting code with V8 intrinsics. ([#6496] by [@rreverser])
+
+<!-- prettier-ignore -->
+```js
+// Input
+function doSmth()     {
+            %DebugPrint
+        (
+                foo )
+  }
+
+// Prettier (stable)
+SyntaxError: Unexpected token (2:13)
+  1 | function doSmth()     {
+> 2 |             %DebugPrint
+    |             ^
+
+// Prettier (master)
+function doSmth() {
+  %DebugPrint(foo);
+}
+```
+
 [#5910]: https://github.com/prettier/prettier/pull/5910
 [#6033]: https://github.com/prettier/prettier/pull/6033
 [#6186]: https://github.com/prettier/prettier/pull/6186
@@ -863,6 +886,7 @@ type D = (keyof T1)["foo"];
 [#6467]: https://github.com/prettier/prettier/pull/6467
 [#6377]: https://github.com/prettier/prettier/pull/6377
 [#6604]: https://github.com/prettier/prettier/pull/6604
+[#6496]: https://github.com/prettier/prettier/pull/6496
 [@brainkim]: https://github.com/brainkim
 [@duailibe]: https://github.com/duailibe
 [@gavinjoyce]: https://github.com/gavinjoyce
@@ -872,3 +896,4 @@ type D = (keyof T1)["foo"];
 [@bakkot]: https://gibhub.com/bakkot
 [@thorn0]: https://github.com/thorn0
 [@dcyriller]: https://github.com/dcyriller
+[@rreverser]: https://github.com/RReverser
diff --git a/src/language-js/parser-babylon.js b/src/language-js/parser-babylon.js
index 2b1a09b032db..08b736bdbaac 100644
--- a/src/language-js/parser-babylon.js
+++ b/src/language-js/parser-babylon.js
@@ -37,7 +37,8 @@ function babelOptions(extraOptions, extraPlugins) {
         "bigInt",
         "throwExpressions",
         "logicalAssignment",
-        "classPrivateMethods"
+        "classPrivateMethods",
+        "v8intrinsic"
       ].concat(extraPlugins)
     },
     extraOptions
diff --git a/src/language-js/printer-estree.js b/src/language-js/printer-estree.js
index 218662cef191..202a57274a1e 100644
--- a/src/language-js/printer-estree.js
+++ b/src/language-js/printer-estree.js
@@ -756,6 +756,8 @@ function printPathNoParens(path, options, print, args) {
         printTypeAnnotation(path, options, print)
       ]);
     }
+    case "V8IntrinsicIdentifier":
+      return concat(["%", n.name]);
     case "SpreadElement":
     case "SpreadElementPattern":
     case "RestProperty":
diff --git a/tests/v8_intrinsic/__snapshots__/jsfmt.spec.js.snap b/tests/v8_intrinsic/__snapshots__/jsfmt.spec.js.snap
new file mode 100644
index 000000000000..0248f069144c
--- /dev/null
+++ b/tests/v8_intrinsic/__snapshots__/jsfmt.spec.js.snap
@@ -0,0 +1,47 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`intrinsic_call.js 1`] = `
+====================================options=====================================
+parsers: ["babel"]
+printWidth: 80
+                                                                                | printWidth
+=====================================input======================================
+function doSmth()     {
+            %DebugPrint
+        (
+                foo )
+  }
+
+    function printFunc  (
+        f
+) {
+    if(%
+    IsAsmWasmCode(f))              console.log("asm.js");
+        if(
+
+        % IsWasmCode(
+        f))
+            console.log (
+                "wasm"
+            );
+
+    console.log
+    (%
+        GetFunctioName(f)
+        );
+}
+
+=====================================output=====================================
+function doSmth() {
+  %DebugPrint(foo);
+}
+
+function printFunc(f) {
+  if (%IsAsmWasmCode(f)) console.log("asm.js");
+  if (%IsWasmCode(f)) console.log("wasm");
+
+  console.log(%GetFunctioName(f));
+}
+
+================================================================================
+`;
diff --git a/tests/v8_intrinsic/intrinsic_call.js b/tests/v8_intrinsic/intrinsic_call.js
new file mode 100644
index 000000000000..43f8bbd7e936
--- /dev/null
+++ b/tests/v8_intrinsic/intrinsic_call.js
@@ -0,0 +1,24 @@
+function doSmth()     {
+            %DebugPrint
+        (
+                foo )
+  }
+
+    function printFunc  (
+        f
+) {
+    if(%
+    IsAsmWasmCode(f))              console.log("asm.js");
+        if(
+
+        % IsWasmCode(
+        f))
+            console.log (
+                "wasm"
+            );
+
+    console.log
+    (%
+        GetFunctioName(f)
+        );
+}
diff --git a/tests/v8_intrinsic/jsfmt.spec.js b/tests/v8_intrinsic/jsfmt.spec.js
new file mode 100644
index 000000000000..8382eddeb1db
--- /dev/null
+++ b/tests/v8_intrinsic/jsfmt.spec.js
@@ -0,0 +1 @@
+run_spec(__dirname, ["babel"]);