From d6ed160448e4bf1a4b43503c4fc19d6913fbf1d4 Mon Sep 17 00:00:00 2001
From: Joyee Cheung <joyeec9h3@gmail.com>
Date: Tue, 30 Jul 2024 12:53:52 +0200
Subject: [PATCH] sea: don't set code cache flags when snapshot is used

When both useCodeCache and useSnapshot are set, we generate the
snapshot and skip the generation of the code cache since the
snapshot already includes the code cache. But we previously still
persist the code cache setting in the flags that got serialized
into the SEA, so the resulting executable would still try to read
the code cache even if it's not added to the SEA, leading to a flaky
crash caused by OOB on some platforms.

This patch fixes the crash by ignoring the code cache setting when
generating the flag if both snapshot and code cache is configured.
---
 src/node_sea.cc | 28 +++++++++++++++-------------
 1 file changed, 15 insertions(+), 13 deletions(-)

diff --git a/src/node_sea.cc b/src/node_sea.cc
index 8c4e3b3579fceb..fb9f933a19fa70 100644
--- a/src/node_sea.cc
+++ b/src/node_sea.cc
@@ -355,7 +355,14 @@ std::optional<SeaConfig> ParseSingleExecutableConfig(
     return std::nullopt;
   }
   if (use_code_cache.value()) {
-    result.flags |= SeaFlags::kUseCodeCache;
+    if (use_snapshot.value()) {
+      // TODO(joyeecheung): code cache in snapshot should be configured by
+      // separate snapshot configurations.
+      FPrintF(stderr,
+              "\"useCodeCache\" is redundant when \"useSnapshot\" is true\n");
+    } else {
+      result.flags |= SeaFlags::kUseCodeCache;
+    }
   }
 
   auto assets_opt = parser.GetTopLevelStringDict("assets");
@@ -511,19 +518,14 @@ ExitCode GenerateSingleExecutableBlob(
   std::optional<std::string_view> optional_sv_code_cache;
   std::string code_cache;
   if (static_cast<bool>(config.flags & SeaFlags::kUseCodeCache)) {
-    if (builds_snapshot_from_main) {
-      FPrintF(stderr,
-              "\"useCodeCache\" is redundant when \"useSnapshot\" is true\n");
-    } else {
-      std::optional<std::string> optional_code_cache =
-          GenerateCodeCache(config.main_path, main_script);
-      if (!optional_code_cache.has_value()) {
-        FPrintF(stderr, "Cannot generate V8 code cache\n");
-        return ExitCode::kGenericUserError;
-      }
-      code_cache = optional_code_cache.value();
-      optional_sv_code_cache = code_cache;
+    std::optional<std::string> optional_code_cache =
+        GenerateCodeCache(config.main_path, main_script);
+    if (!optional_code_cache.has_value()) {
+      FPrintF(stderr, "Cannot generate V8 code cache\n");
+      return ExitCode::kGenericUserError;
     }
+    code_cache = optional_code_cache.value();
+    optional_sv_code_cache = code_cache;
   }
 
   std::unordered_map<std::string, std::string> assets;