From c252984cbf5fa512a5f05aa9edef8c9f187ee0ed Mon Sep 17 00:00:00 2001
From: Mike Rolig <mrolig@google.com>
Date: Wed, 24 Jan 2024 12:57:40 -0800
Subject: [PATCH 01/13] Refactor Emval JavaScript implementation to avoid heap
 allocation.

---
 src/embind/emval.js | 68 ++++++++++++++++++++++++++-------------------
 1 file changed, 39 insertions(+), 29 deletions(-)

diff --git a/src/embind/emval.js b/src/embind/emval.js
index 174834aa64a3c..3c9ddbb2055c0 100644
--- a/src/embind/emval.js
+++ b/src/embind/emval.js
@@ -12,39 +12,39 @@
 /*jslint sub:true*/ /* The symbols 'fromWireType' and 'toWireType' must be accessed via array notation to be closure-safe since craftInvokerFunction crafts functions as strings that can't be closured. */
 
 // -- jshint doesn't understand library syntax, so we need to mark the symbols exposed here
-/*global getStringOrSymbol, emval_handles, Emval, __emval_unregister, count_emval_handles, emval_symbols, __emval_decref*/
+/*global getStringOrSymbol, emval_freelist, emval_handles, emval_handles_reserved, Emval, __emval_unregister, count_emval_handles, emval_symbols, __emval_decref*/
 /*global emval_addMethodCaller, emval_methodCallers, addToLibrary, global, emval_lookupTypes, makeLegalFunctionName*/
 /*global emval_get_global*/
 
 var LibraryEmVal = {
-  $emval_handles__deps: ['$HandleAllocator'],
-  $emval_handles: "new HandleAllocator();",
+  // Stack of handles available for reuse.
+  $emval_freelist: [],
+  // Array of alternating pairs (value, refcount).
+  $emval_handles: [],
+  // Number of handles reserved for non-use (0) or common values w/o refcount.
+  $emval_handles_reserved: 5,
   $emval_symbols: {}, // address -> string
 
-  $init_emval__deps: ['$count_emval_handles', '$emval_handles'],
+  $init_emval__deps: ['$count_emval_handles', '$emval_handles', '$emval_handles_reserved'],
   $init_emval__postset: 'init_emval();',
   $init_emval: () => {
-    // reserve some special values. These never get de-allocated.
-    // The HandleAllocator takes care of reserving zero.
-    emval_handles.allocated.push(
-      {value: undefined},
-      {value: null},
-      {value: true},
-      {value: false},
+    // reserve 0 and some special values. These never get de-allocated.
+    emval_handles.push(
+      0, 0,
+      undefined, 0,
+      null, 0,
+      true, 0,
+      false, 0,
     );
-    Object.assign(emval_handles, /** @lends {emval_handles} */ { reserved: emval_handles.allocated.length }),
+  #if ASSERTIONS
+    assert(emval_handles.length / 2 === emval_handles_reserved);
+  #endif
     Module['count_emval_handles'] = count_emval_handles;
   },
 
-  $count_emval_handles__deps: ['$emval_handles'],
+  $count_emval_handles__deps: ['$emval_freelist', '$emval_handles', '$emval_handles_reserved'],
   $count_emval_handles: () => {
-    var count = 0;
-    for (var i = emval_handles.reserved; i < emval_handles.allocated.length; ++i) {
-      if (emval_handles.allocated[i] !== undefined) {
-        ++count;
-      }
-    }
-    return count;
+    return emval_handles.length / 2 - emval_handles_reserved - emval_freelist.length;
   },
 
   _emval_register_symbol__deps: ['$emval_symbols', '$readLatin1String'],
@@ -61,13 +61,16 @@ var LibraryEmVal = {
     return symbol;
   },
 
-  $Emval__deps: ['$emval_handles', '$throwBindingError', '$init_emval'],
+  $Emval__deps: ['$emval_freelist', '$emval_handles', '$throwBindingError', '$init_emval'],
   $Emval: {
     toValue: (handle) => {
       if (!handle) {
           throwBindingError('Cannot use deleted val. handle = ' + handle);
       }
-      return emval_handles.get(handle).value;
+  #if ASSERTIONS
+      assert(handle === 1 || emval_handles[handle * 2] !== undefined, `invalid handle: ${handle}`);
+  #endif
+      return emval_handles[handle * 2];
     },
 
     toHandle: (value) => {
@@ -77,23 +80,30 @@ var LibraryEmVal = {
         case true: return 3;
         case false: return 4;
         default:{
-          return emval_handles.allocate({refcount: 1, value: value});
+          const handle = emval_freelist.pop() || emval_handles.length / 2;
+          emval_handles[handle * 2] = value;
+          emval_handles[handle * 2 + 1] = 1;
+          return handle;
         }
       }
     }
   },
 
-  _emval_incref__deps: ['$emval_handles'],
+  _emval_incref__deps: ['$emval_handles', '$emval_handles_reserved'],
   _emval_incref: (handle) => {
-    if (handle > 4) {
-      emval_handles.get(handle).refcount += 1;
+    if (handle >= emval_handles_Reserved) {
+      emval_handles[handle * 2 + 1] += 1;
     }
   },
 
-  _emval_decref__deps: ['$emval_handles'],
+  _emval_decref__deps: ['$emval_freelist', '$emval_handles', '$emval_handles_reserved'],
   _emval_decref: (handle) => {
-    if (handle >= emval_handles.reserved && 0 === --emval_handles.get(handle).refcount) {
-      emval_handles.free(handle);
+    if (handle >= emval_handles_reserved && 0 === --emval_handles[handle * 2 + 1]).refcount) {
+  #if ASSERTIONS
+      assert(emval_handles[handle * 2] !== undefined);
+  #endif
+      emval_handles[handle * 2] = undefined;
+      emval_freelist.push(handle);
     }
   },
 

From d90ee09428b017c84985a1c5e9aaa1b3de725391 Mon Sep 17 00:00:00 2001
From: Mike Rolig <mrolig@google.com>
Date: Wed, 24 Jan 2024 13:14:46 -0800
Subject: [PATCH 02/13] fix syntax errors

---
 src/embind/emval.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/embind/emval.js b/src/embind/emval.js
index 3c9ddbb2055c0..429dd173a525e 100644
--- a/src/embind/emval.js
+++ b/src/embind/emval.js
@@ -98,7 +98,7 @@ var LibraryEmVal = {
 
   _emval_decref__deps: ['$emval_freelist', '$emval_handles', '$emval_handles_reserved'],
   _emval_decref: (handle) => {
-    if (handle >= emval_handles_reserved && 0 === --emval_handles[handle * 2 + 1]).refcount) {
+    if (handle >= emval_handles_reserved && 0 === --emval_handles[handle * 2 + 1]) {
   #if ASSERTIONS
       assert(emval_handles[handle * 2] !== undefined);
   #endif

From 9639b41d8cc4d56dfffd34ca00ca8e0ec2d2fe1e Mon Sep 17 00:00:00 2001
From: Mike Rolig <mrolig@google.com>
Date: Mon, 29 Jan 2024 10:52:52 -0800
Subject: [PATCH 03/13] fix typo

---
 src/embind/emval.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/embind/emval.js b/src/embind/emval.js
index 429dd173a525e..09417a3184877 100644
--- a/src/embind/emval.js
+++ b/src/embind/emval.js
@@ -91,7 +91,7 @@ var LibraryEmVal = {
 
   _emval_incref__deps: ['$emval_handles', '$emval_handles_reserved'],
   _emval_incref: (handle) => {
-    if (handle >= emval_handles_Reserved) {
+    if (handle >= emval_handles_reserved) {
       emval_handles[handle * 2 + 1] += 1;
     }
   },

From 9752e50521fe2474c2d58075dea8fc34d357d5dc Mon Sep 17 00:00:00 2001
From: Mike Rolig <mrolig@google.com>
Date: Tue, 30 Jan 2024 12:49:39 -0800
Subject: [PATCH 04/13] Updates from code review.

---
 src/embind/emval.js | 39 +++++++++++++++++++++------------------
 1 file changed, 21 insertions(+), 18 deletions(-)

diff --git a/src/embind/emval.js b/src/embind/emval.js
index 09417a3184877..26bcb60f1a2a2 100644
--- a/src/embind/emval.js
+++ b/src/embind/emval.js
@@ -12,39 +12,42 @@
 /*jslint sub:true*/ /* The symbols 'fromWireType' and 'toWireType' must be accessed via array notation to be closure-safe since craftInvokerFunction crafts functions as strings that can't be closured. */
 
 // -- jshint doesn't understand library syntax, so we need to mark the symbols exposed here
-/*global getStringOrSymbol, emval_freelist, emval_handles, emval_handles_reserved, Emval, __emval_unregister, count_emval_handles, emval_symbols, __emval_decref*/
+/*global getStringOrSymbol, emval_freelist, emval_handles, Emval, __emval_unregister, count_emval_handles, emval_symbols, __emval_decref*/
 /*global emval_addMethodCaller, emval_methodCallers, addToLibrary, global, emval_lookupTypes, makeLegalFunctionName*/
 /*global emval_get_global*/
 
+// Number of handles reserved for non-use (0) or common values w/o refcount.
+{{{ 
+  globalThis.EMVAL_RESERVED_HANDLES = 5;
+  null;
+}}}
 var LibraryEmVal = {
   // Stack of handles available for reuse.
   $emval_freelist: [],
   // Array of alternating pairs (value, refcount).
   $emval_handles: [],
-  // Number of handles reserved for non-use (0) or common values w/o refcount.
-  $emval_handles_reserved: 5,
   $emval_symbols: {}, // address -> string
 
-  $init_emval__deps: ['$count_emval_handles', '$emval_handles', '$emval_handles_reserved'],
+  $init_emval__deps: ['$count_emval_handles', '$emval_handles'],
   $init_emval__postset: 'init_emval();',
   $init_emval: () => {
     // reserve 0 and some special values. These never get de-allocated.
     emval_handles.push(
-      0, 0,
-      undefined, 0,
-      null, 0,
-      true, 0,
-      false, 0,
+      0, 1,
+      undefined, 1,
+      null, 1,
+      true, 1,
+      false, 1,
     );
   #if ASSERTIONS
-    assert(emval_handles.length / 2 === emval_handles_reserved);
+    assert(emval_handles.length / 2 === {{{ EMVAL_RESERVED_HANDLES }}});
   #endif
     Module['count_emval_handles'] = count_emval_handles;
   },
 
-  $count_emval_handles__deps: ['$emval_freelist', '$emval_handles', '$emval_handles_reserved'],
+  $count_emval_handles__deps: ['$emval_freelist', '$emval_handles'],
   $count_emval_handles: () => {
-    return emval_handles.length / 2 - emval_handles_reserved - emval_freelist.length;
+    return emval_handles.length / 2 - {{{ EMVAL_RESERVED_HANDLES }}}- emval_freelist.length;
   },
 
   _emval_register_symbol__deps: ['$emval_symbols', '$readLatin1String'],
@@ -68,6 +71,7 @@ var LibraryEmVal = {
           throwBindingError('Cannot use deleted val. handle = ' + handle);
       }
   #if ASSERTIONS
+      // handle 1 is supposed to be `undefined`.
       assert(handle === 1 || emval_handles[handle * 2] !== undefined, `invalid handle: ${handle}`);
   #endif
       return emval_handles[handle * 2];
@@ -89,17 +93,16 @@ var LibraryEmVal = {
     }
   },
 
-  _emval_incref__deps: ['$emval_handles', '$emval_handles_reserved'],
+  _emval_incref__deps: ['$emval_handles'],
   _emval_incref: (handle) => {
-    if (handle >= emval_handles_reserved) {
-      emval_handles[handle * 2 + 1] += 1;
-    }
+    emval_handles[handle * 2 + 1] += 1;
   },
 
-  _emval_decref__deps: ['$emval_freelist', '$emval_handles', '$emval_handles_reserved'],
+  _emval_decref__deps: ['$emval_freelist', '$emval_handles'],
   _emval_decref: (handle) => {
-    if (handle >= emval_handles_reserved && 0 === --emval_handles[handle * 2 + 1]) {
+    if (0 === --emval_handles[handle * 2 + 1]) {
   #if ASSERTIONS
+      assert(handle >= {{{ EMVAL_RESERVED_HANDLES }}});
       assert(emval_handles[handle * 2] !== undefined);
   #endif
       emval_handles[handle * 2] = undefined;

From 889193c18e9d397d324b959f072cb723aba4cd79 Mon Sep 17 00:00:00 2001
From: Mike Rolig <mrolig@google.com>
Date: Tue, 30 Jan 2024 12:58:00 -0800
Subject: [PATCH 05/13] Rebaseline
 test_minimal_runtime_code_size_hello_embind_val.

---
 test/code_size/embind_val_wasm.json | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/test/code_size/embind_val_wasm.json b/test/code_size/embind_val_wasm.json
index 77462a448e15a..99b4dbd81fe13 100644
--- a/test/code_size/embind_val_wasm.json
+++ b/test/code_size/embind_val_wasm.json
@@ -1,10 +1,10 @@
 {
   "a.html": 673,
   "a.html.gz": 431,
-  "a.js": 7411,
-  "a.js.gz": 3140,
-  "a.wasm": 11433,
-  "a.wasm.gz": 5725,
-  "total": 19517,
-  "total_gz": 9296
+  "a.js": 7178,
+  "a.js.gz": 3052,
+  "a.wasm": 11439,
+  "a.wasm.gz": 5729,
+  "total": 19290,
+  "total_gz": 9212
 }

From fdc625ffff5d956bce93e2d716110ce217d900a7 Mon Sep 17 00:00:00 2001
From: Mike Rolig <mrolig@google.com>
Date: Tue, 30 Jan 2024 13:03:44 -0800
Subject: [PATCH 06/13] Rebaseline
 test_minimal_runtime_code_size_hello_embind_val.

---
 test/code_size/embind_val_wasm.json | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/test/code_size/embind_val_wasm.json b/test/code_size/embind_val_wasm.json
index 99b4dbd81fe13..74e94e06eff60 100644
--- a/test/code_size/embind_val_wasm.json
+++ b/test/code_size/embind_val_wasm.json
@@ -1,10 +1,10 @@
 {
   "a.html": 673,
   "a.html.gz": 431,
-  "a.js": 7178,
-  "a.js.gz": 3052,
-  "a.wasm": 11439,
-  "a.wasm.gz": 5729,
-  "total": 19290,
-  "total_gz": 9212
+  "a.js": 7155,
+  "a.js.gz": 3022,
+  "a.wasm": 11433,
+  "a.wasm.gz": 5725,
+  "total": 19261,
+  "total_gz": 9178
 }

From 3c2e5e6bc2ff30429af1172c6c78e86427481f14 Mon Sep 17 00:00:00 2001
From: Mike Rolig <mrolig@google.com>
Date: Tue, 30 Jan 2024 14:19:42 -0800
Subject: [PATCH 07/13] Fix test_embind_val

---
 src/embind/emval.js | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/src/embind/emval.js b/src/embind/emval.js
index 26bcb60f1a2a2..390722e58c7f6 100644
--- a/src/embind/emval.js
+++ b/src/embind/emval.js
@@ -19,6 +19,7 @@
 // Number of handles reserved for non-use (0) or common values w/o refcount.
 {{{ 
   globalThis.EMVAL_RESERVED_HANDLES = 5;
+  globalThis.EMVAL_LAST_RESERVED_HANDLE = globalThis.EMVAL_RESERVED_HANDLES - 1;
   null;
 }}}
 var LibraryEmVal = {
@@ -95,15 +96,16 @@ var LibraryEmVal = {
 
   _emval_incref__deps: ['$emval_handles'],
   _emval_incref: (handle) => {
-    emval_handles[handle * 2 + 1] += 1;
+    if (handle > {{{ EMVAL_LAST_RESERVED_HANDLE }}}) {
+      emval_handles[handle * 2 + 1] += 1;
+    }
   },
 
   _emval_decref__deps: ['$emval_freelist', '$emval_handles'],
   _emval_decref: (handle) => {
-    if (0 === --emval_handles[handle * 2 + 1]) {
+    if (handle > {{{ EMVAL_LAST_RESERVED_HANDLE }}} && 0 === --emval_handles[handle * 2 + 1]) {
   #if ASSERTIONS
-      assert(handle >= {{{ EMVAL_RESERVED_HANDLES }}});
-      assert(emval_handles[handle * 2] !== undefined);
+      assert(emval_handles[handle * 2] !== undefined, `Decref for unallocated handle.`);
   #endif
       emval_handles[handle * 2] = undefined;
       emval_freelist.push(handle);

From 237bd2f3b7f8ff501e9168b50478efbde061abe3 Mon Sep 17 00:00:00 2001
From: Mike Rolig <mrolig@google.com>
Date: Tue, 30 Jan 2024 14:20:29 -0800
Subject: [PATCH 08/13] Rebaseline
 test_minimal_runtime_code_size_hello_embind_val.

---
 test/code_size/embind_val_wasm.json | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/test/code_size/embind_val_wasm.json b/test/code_size/embind_val_wasm.json
index 74e94e06eff60..702b778c9c15b 100644
--- a/test/code_size/embind_val_wasm.json
+++ b/test/code_size/embind_val_wasm.json
@@ -1,10 +1,10 @@
 {
   "a.html": 673,
   "a.html.gz": 431,
-  "a.js": 7155,
-  "a.js.gz": 3022,
+  "a.js": 7160,
+  "a.js.gz": 3027,
   "a.wasm": 11433,
   "a.wasm.gz": 5725,
-  "total": 19261,
-  "total_gz": 9178
+  "total": 19266,
+  "total_gz": 9183
 }

From ece8ec58c3a0352e9e2df51751f8acad5445ac5e Mon Sep 17 00:00:00 2001
From: Mike Rolig <mrolig@google.com>
Date: Tue, 30 Jan 2024 14:30:18 -0800
Subject: [PATCH 09/13] Fix formating

---
 src/embind/emval.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/embind/emval.js b/src/embind/emval.js
index 390722e58c7f6..a86bcee280b6d 100644
--- a/src/embind/emval.js
+++ b/src/embind/emval.js
@@ -48,7 +48,7 @@ var LibraryEmVal = {
 
   $count_emval_handles__deps: ['$emval_freelist', '$emval_handles'],
   $count_emval_handles: () => {
-    return emval_handles.length / 2 - {{{ EMVAL_RESERVED_HANDLES }}}- emval_freelist.length;
+    return emval_handles.length / 2 - {{{ EMVAL_RESERVED_HANDLES }}} - emval_freelist.length;
   },
 
   _emval_register_symbol__deps: ['$emval_symbols', '$readLatin1String'],

From d823c3e11bb0187f1870b56fe2da20a96ee058d4 Mon Sep 17 00:00:00 2001
From: Mike Rolig <mrolig@google.com>
Date: Mon, 5 Feb 2024 12:25:13 -0800
Subject: [PATCH 10/13] Rebaseline
 test_minimal_runtime_code_size_hello_embind_val.

---
 test/code_size/embind_val_wasm.json | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/test/code_size/embind_val_wasm.json b/test/code_size/embind_val_wasm.json
index fe8049be2eb2e..d95d1d4511a82 100644
--- a/test/code_size/embind_val_wasm.json
+++ b/test/code_size/embind_val_wasm.json
@@ -1,10 +1,10 @@
 {
   "a.html": 673,
   "a.html.gz": 431,
-  "a.js": 7325,
-  "a.js.gz": 3088,
+  "a.js": 7098,
+  "a.js.gz": 3001,
   "a.wasm": 11433,
   "a.wasm.gz": 5725,
-  "total": 19431,
-  "total_gz": 9244
+  "total": 19204,
+  "total_gz": 9157
 }

From 5e2f3bd5e05fd249463856059aff2f46e5979de3 Mon Sep 17 00:00:00 2001
From: Mike Rolig <mrolig@google.com>
Date: Wed, 7 Feb 2024 11:33:30 -0800
Subject: [PATCH 11/13] Simplify handle code paths even if it means halving the
 address space.

---
 src/embind/emval.js                 | 34 ++++++++++++++---------------
 system/include/emscripten/val.h     |  8 +++----
 test/code_size/embind_val_wasm.json |  8 +++----
 3 files changed, 25 insertions(+), 25 deletions(-)

diff --git a/src/embind/emval.js b/src/embind/emval.js
index a86bcee280b6d..0f03cba8a7db7 100644
--- a/src/embind/emval.js
+++ b/src/embind/emval.js
@@ -18,7 +18,7 @@
 
 // Number of handles reserved for non-use (0) or common values w/o refcount.
 {{{ 
-  globalThis.EMVAL_RESERVED_HANDLES = 5;
+  globalThis.EMVAL_RESERVED_HANDLES = 10;
   globalThis.EMVAL_LAST_RESERVED_HANDLE = globalThis.EMVAL_RESERVED_HANDLES - 1;
   null;
 }}}
@@ -41,14 +41,14 @@ var LibraryEmVal = {
       false, 1,
     );
   #if ASSERTIONS
-    assert(emval_handles.length / 2 === {{{ EMVAL_RESERVED_HANDLES }}});
+    assert(emval_handles.length === {{{ EMVAL_RESERVED_HANDLES }}});
   #endif
     Module['count_emval_handles'] = count_emval_handles;
   },
 
   $count_emval_handles__deps: ['$emval_freelist', '$emval_handles'],
   $count_emval_handles: () => {
-    return emval_handles.length / 2 - {{{ EMVAL_RESERVED_HANDLES }}} - emval_freelist.length;
+    return (emval_handles.length - {{{ EMVAL_RESERVED_HANDLES }}}) / 2 - emval_freelist.length;
   },
 
   _emval_register_symbol__deps: ['$emval_symbols', '$readLatin1String'],
@@ -72,22 +72,22 @@ var LibraryEmVal = {
           throwBindingError('Cannot use deleted val. handle = ' + handle);
       }
   #if ASSERTIONS
-      // handle 1 is supposed to be `undefined`.
-      assert(handle === 1 || emval_handles[handle * 2] !== undefined, `invalid handle: ${handle}`);
+      // handle 2 is supposed to be `undefined`.
+      assert(handle === 2 || emval_handles[handle] !== undefined, `invalid handle: ${handle}`);
   #endif
-      return emval_handles[handle * 2];
+      return emval_handles[handle];
     },
 
     toHandle: (value) => {
       switch (value) {
-        case undefined: return 1;
-        case null: return 2;
-        case true: return 3;
-        case false: return 4;
+        case undefined: return 2;
+        case null: return 4;
+        case true: return 6;
+        case false: return 8;
         default:{
-          const handle = emval_freelist.pop() || emval_handles.length / 2;
-          emval_handles[handle * 2] = value;
-          emval_handles[handle * 2 + 1] = 1;
+          const handle = emval_freelist.pop() || emval_handles.length;
+          emval_handles[handle] = value;
+          emval_handles[handle + 1] = 1;
           return handle;
         }
       }
@@ -97,17 +97,17 @@ var LibraryEmVal = {
   _emval_incref__deps: ['$emval_handles'],
   _emval_incref: (handle) => {
     if (handle > {{{ EMVAL_LAST_RESERVED_HANDLE }}}) {
-      emval_handles[handle * 2 + 1] += 1;
+      emval_handles[handle + 1] += 1;
     }
   },
 
   _emval_decref__deps: ['$emval_freelist', '$emval_handles'],
   _emval_decref: (handle) => {
-    if (handle > {{{ EMVAL_LAST_RESERVED_HANDLE }}} && 0 === --emval_handles[handle * 2 + 1]) {
+    if (handle > {{{ EMVAL_LAST_RESERVED_HANDLE }}} && 0 === --emval_handles[handle + 1]) {
   #if ASSERTIONS
-      assert(emval_handles[handle * 2] !== undefined, `Decref for unallocated handle.`);
+      assert(emval_handles[handle] !== undefined, `Decref for unallocated handle.`);
   #endif
-      emval_handles[handle * 2] = undefined;
+      emval_handles[handle] = undefined;
       emval_freelist.push(handle);
     }
   },
diff --git a/system/include/emscripten/val.h b/system/include/emscripten/val.h
index 83efee02cb99e..81e7c0d2e88f2 100644
--- a/system/include/emscripten/val.h
+++ b/system/include/emscripten/val.h
@@ -46,10 +46,10 @@ extern "C" {
 void _emval_register_symbol(const char*);
 
 enum {
-  _EMVAL_UNDEFINED = 1,
-  _EMVAL_NULL = 2,
-  _EMVAL_TRUE = 3,
-  _EMVAL_FALSE = 4
+  _EMVAL_UNDEFINED = 2,
+  _EMVAL_NULL = 4,
+  _EMVAL_TRUE = 6,
+  _EMVAL_FALSE = 8
 };
 
 typedef struct _EM_DESTRUCTORS* EM_DESTRUCTORS;
diff --git a/test/code_size/embind_val_wasm.json b/test/code_size/embind_val_wasm.json
index d95d1d4511a82..ce9d73f675655 100644
--- a/test/code_size/embind_val_wasm.json
+++ b/test/code_size/embind_val_wasm.json
@@ -1,10 +1,10 @@
 {
   "a.html": 673,
   "a.html.gz": 431,
-  "a.js": 7098,
-  "a.js.gz": 3001,
+  "a.js": 7089,
+  "a.js.gz": 3002,
   "a.wasm": 11433,
   "a.wasm.gz": 5725,
-  "total": 19204,
-  "total_gz": 9157
+  "total": 19195,
+  "total_gz": 9158
 }

From b06380fddcff7843e30d7653c3c2a4c00b7d5a4f Mon Sep 17 00:00:00 2001
From: Mike Rolig <mrolig@google.com>
Date: Wed, 7 Feb 2024 11:37:22 -0800
Subject: [PATCH 12/13] Assert that handles are even when validating.

---
 src/embind/emval.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/embind/emval.js b/src/embind/emval.js
index 0f03cba8a7db7..d5f08bf45c2dc 100644
--- a/src/embind/emval.js
+++ b/src/embind/emval.js
@@ -73,7 +73,7 @@ var LibraryEmVal = {
       }
   #if ASSERTIONS
       // handle 2 is supposed to be `undefined`.
-      assert(handle === 2 || emval_handles[handle] !== undefined, `invalid handle: ${handle}`);
+      assert(handle === 2 || emval_handles[handle] !== undefined && handle % 2 === 0, `invalid handle: ${handle}`);
   #endif
       return emval_handles[handle];
     },

From a6586c13378e766f6055e31dab3bf6fdc14df69d Mon Sep 17 00:00:00 2001
From: Mike Rolig <mrolig@google.com>
Date: Wed, 7 Feb 2024 16:49:56 -0800
Subject: [PATCH 13/13] Keep EMVAL_RESERVED_HANDLES as 5 for clarity.

---
 src/embind/emval.js                 | 8 ++++----
 test/code_size/embind_val_wasm.json | 8 ++++----
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/src/embind/emval.js b/src/embind/emval.js
index cb0113149b748..8d22ae24839ad 100644
--- a/src/embind/emval.js
+++ b/src/embind/emval.js
@@ -18,8 +18,8 @@
 
 // Number of handles reserved for non-use (0) or common values w/o refcount.
 {{{ 
-  globalThis.EMVAL_RESERVED_HANDLES = 10;
-  globalThis.EMVAL_LAST_RESERVED_HANDLE = globalThis.EMVAL_RESERVED_HANDLES - 1;
+  globalThis.EMVAL_RESERVED_HANDLES = 5;
+  globalThis.EMVAL_LAST_RESERVED_HANDLE = globalThis.EMVAL_RESERVED_HANDLES * 2 - 1;
   null;
 }}}
 var LibraryEmVal = {
@@ -41,14 +41,14 @@ var LibraryEmVal = {
       false, 1,
     );
   #if ASSERTIONS
-    assert(emval_handles.length === {{{ EMVAL_RESERVED_HANDLES }}});
+    assert(emval_handles.length === {{{ EMVAL_RESERVED_HANDLES }}} * 2);
   #endif
     Module['count_emval_handles'] = count_emval_handles;
   },
 
   $count_emval_handles__deps: ['$emval_freelist', '$emval_handles'],
   $count_emval_handles: () => {
-    return (emval_handles.length - {{{ EMVAL_RESERVED_HANDLES }}}) / 2 - emval_freelist.length;
+    return emval_handles.length / 2 - {{{ EMVAL_RESERVED_HANDLES }}} - emval_freelist.length;
   },
 
   _emval_register_symbol__deps: ['$emval_symbols', '$readLatin1String'],
diff --git a/test/code_size/embind_val_wasm.json b/test/code_size/embind_val_wasm.json
index ce9d73f675655..a199731962377 100644
--- a/test/code_size/embind_val_wasm.json
+++ b/test/code_size/embind_val_wasm.json
@@ -1,10 +1,10 @@
 {
   "a.html": 673,
   "a.html.gz": 431,
-  "a.js": 7089,
-  "a.js.gz": 3002,
+  "a.js": 7086,
+  "a.js.gz": 3000,
   "a.wasm": 11433,
   "a.wasm.gz": 5725,
-  "total": 19195,
-  "total_gz": 9158
+  "total": 19192,
+  "total_gz": 9156
 }