deps: cherry-pick e020aae394 from V8 upstream

Original commit message: Work around glibc thread-local storage bug glibc before 2.17 has a bug that makes it impossible to execute binaries that have single-byte thread-local variables: % node --version node: error while loading shared libraries: cannot allocate memory in static TLS block Work around that by making the one instance in the V8 code base an int. See: https://sourceware.org/bugzilla/show_bug.cgi?id=14898 See: nodesource/distributions#513 See: nodejs/build#809 Change-Id: Iefd8009100cd93e26cf8dc5dc03f2d622b423385 Reviewed-on: https://chromium-review.googlesource.com/612351 Commit-Queue: Ben Noordhuis <info@bnoordhuis.nl> Reviewed-by: Eric Holk <eholk@chromium.org> Cr-Commit-Position: refs/heads/master@{#47400} Backport-PR-URL: #15393 PR-URL: #14913 Ref: nodejs/build#809 Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl> Reviewed-By: Michaël Zasso <targos@protonmail.com> Reviewed-By: Nikolai Vavilov <vvnicholas@gmail.com> Reviewed-By: Colin Ihrig <cjihrig@gmail.com> Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com> Reviewed-By: James M Snell <jasnell@gmail.com>
nodejs · tniessen · Sep 19, 2017 · Sep 21, 2017 · May 11, 2017 · Sep 21, 2017
commit d336d2a721aa59a068b3c4ea717c531d690d79aa
diff --git a/deps/v8/src/trap-handler/handler-shared.cc b/deps/v8/src/trap-handler/handler-shared.cc
@@ -23,7 +23,14 @@ namespace v8 {
 namespace internal {
 namespace trap_handler {
 
-THREAD_LOCAL bool g_thread_in_wasm_code = false;
+// We declare this as int rather than bool as a workaround for a glibc bug, in
+// which the dynamic loader cannot handle executables whose TLS area is only
+// 1 byte in size; see https://sourceware.org/bugzilla/show_bug.cgi?id=14898.
+THREAD_LOCAL int g_thread_in_wasm_code = false;
+
+static_assert(sizeof(g_thread_in_wasm_code) > 1,
+              "sizeof(thread_local_var) must be > 1, see "
+              "https://sourceware.org/bugzilla/show_bug.cgi?id=14898");
 
 size_t gNumCodeObjects = 0;
 CodeProtectionInfoListEntry* gCodeObjects = nullptr;

diff --git a/deps/v8/src/trap-handler/trap-handler.h b/deps/v8/src/trap-handler/trap-handler.h
@@ -65,7 +65,7 @@ inline bool UseTrapHandler() {
   return FLAG_wasm_trap_handler && V8_TRAP_HANDLER_SUPPORTED;
 }
 
-extern THREAD_LOCAL bool g_thread_in_wasm_code;
+extern THREAD_LOCAL int g_thread_in_wasm_code;
 
 inline bool IsThreadInWasm() { return g_thread_in_wasm_code; }