Changeset 215522 in webkit for trunk/Source/JavaScriptCore/runtime/VMTraps.cpp

Timestamp:

Apr 19, 2017, 11:25:43 AM (8 years ago)

Author:

[email protected]

Message:

Cannot compile JavaScriptCore/runtime/VMTraps.cpp on FreeBSD because std::pair has a non-trivial copy constructor
​https://bugs.webkit.org/show_bug.cgi?id=170875

Reviewed by Mark Lam.

WTF::ExpectedDetail::ConstexprBase doesn't have a user-defined
copy constructor, and its implicitly-defined copy constructor is
deleted because the default std::pair implementation on FreeBSD
has a non-trivial copy constructor. /usr/include/c++/v1/config
says _LIBCPP_TRIVIAL_PAIR_COPY_CTOR is disabled in order to keep
ABI compatibility:
​https://svnweb.freebsd.org/changeset/base/261801.

That's a huge bummer, and I'm not a fan of broken stdlibs, but in
this case it's pretty nice to have a custom named type anyways and
costs nothing.

• runtime/VMTraps.cpp:

(JSC::findActiveVMAndStackBounds):
(JSC::handleSigusr1):
(JSC::handleSigtrap):

File:

• trunk/Source/JavaScriptCore/runtime/VMTraps.cpp (modified) (4 diffs)

trunk/Source/JavaScriptCore/runtime/VMTraps.cpp

@@ -89 +89 @@
 }
 
-static Expected<std::pair<VM*, StackBounds>, VMTraps::Error> findActiveVMAndStackBounds(SignalContext& context)
+struct VMAndStackBounds {
+    VM* vm;
+    StackBounds stackBounds;
+};
+
+static Expected<VMAndStackBounds, VMTraps::Error> findActiveVMAndStackBounds(SignalContext& context)
 {
     VMInspector& inspector = VMInspector::instance();
@@ -125 +130 @@
     if (!activeVM && unableToAcquireMachineThreadsLock)
         return makeUnexpected(VMTraps::Error::LockUnavailable);
-    return std::make_pair(activeVM, stackBounds);
+    return VMAndStackBounds { activeVM, stackBounds };
 }
 
@@ -133 +138 @@
     auto activeVMAndStackBounds = findActiveVMAndStackBounds(context);
     if (activeVMAndStackBounds) {
-        VM* vm = activeVMAndStackBounds.value().first;
+        VM* vm = activeVMAndStackBounds.value().vm;
         if (vm) {
-            StackBounds stackBounds = activeVMAndStackBounds.value().second;
+            StackBounds stackBounds = activeVMAndStackBounds.value().stackBounds;
             VMTraps& traps = vm->traps();
             if (traps.needTrapHandling())
@@ -154 +159 @@
         return; // Let the SignalSender try again later.
 
-    VM* vm = activeVMAndStackBounds.value().first;
+    VM* vm = activeVMAndStackBounds.value().vm;
     if (vm) {
         VMTraps& traps = vm->traps();