Changeset 215638 in webkit for trunk/Source/JavaScriptCore/runtime/VMTraps.cpp

Timestamp:

Apr 21, 2017, 2:28:17 PM (8 years ago)

Author:

[email protected]

Message:

Unreviewed, rolling out r215634.

underlying build issues should have been fixed

Reverted changeset:

"Unreviewed, rolling out r215620 and r215623."
​https://bugs.webkit.org/show_bug.cgi?id=171139
​http://trac.webkit.org/changeset/215634

File:

• trunk/Source/JavaScriptCore/runtime/VMTraps.cpp (modified) (5 diffs)

trunk/Source/JavaScriptCore/runtime/VMTraps.cpp

@@ -41 +41 @@
 #include "Watchdog.h"
 #include <wtf/ProcessID.h>
-
-#if OS(DARWIN)
-#include <signal.h>
-#endif
+#include <wtf/ThreadMessage.h>
+#include <wtf/threads/Signals.h>
 
 namespace JSC {
@@ -54 +52 @@
 
 #if ENABLE(SIGNAL_BASED_VM_TRAPS)
-
-struct sigaction originalSigusr1Action;
-struct sigaction originalSigtrapAction;
 
 struct SignalContext {
@@ -133 +128 @@
 }
 
-static void handleSigusr1(int signalNumber, siginfo_t* info, void* uap)
-{
-    SignalContext context(static_cast<ucontext_t*>(uap)->uc_mcontext);
-    auto activeVMAndStackBounds = findActiveVMAndStackBounds(context);
-    if (activeVMAndStackBounds) {
+static void installSignalHandler()
+{
+    installSignalHandler(Signal::Trap, [] (int, siginfo_t*, void* uap) -> SignalAction {
+        SignalContext context(static_cast<ucontext_t*>(uap)->uc_mcontext);
+
+        if (!isJITPC(context.trapPC))
+            return SignalAction::NotHandled;
+
+        // FIXME: This currently eats all traps including jit asserts we should make sure this
+        // always works. https://bugs.webkit.org/show_bug.cgi?id=171039
+        auto activeVMAndStackBounds = findActiveVMAndStackBounds(context);
+        if (!activeVMAndStackBounds)
+            return SignalAction::Handled; // Let the SignalSender try again later.
+
         VM* vm = activeVMAndStackBounds.value().vm;
         if (vm) {
-            StackBounds stackBounds = activeVMAndStackBounds.value().stackBounds;
             VMTraps& traps = vm->traps();
-            if (traps.needTrapHandling())
-                traps.tryInstallTrapBreakpoints(context, stackBounds);
-        }
-    }
-
-    auto originalAction = originalSigusr1Action.sa_sigaction;
-    if (originalAction)
-        originalAction(signalNumber, info, uap);
-}
-
-static void handleSigtrap(int signalNumber, siginfo_t* info, void* uap)
-{
-    SignalContext context(static_cast<ucontext_t*>(uap)->uc_mcontext);
-    auto activeVMAndStackBounds = findActiveVMAndStackBounds(context);
-    if (!activeVMAndStackBounds)
-        return; // Let the SignalSender try again later.
-
-    VM* vm = activeVMAndStackBounds.value().vm;
-    if (vm) {
-        VMTraps& traps = vm->traps();
-        if (!traps.needTrapHandling())
-            return; // The polling code beat us to handling the trap already.
-
-        auto expectedSuccess = traps.tryJettisonCodeBlocksOnStack(context);
-        if (!expectedSuccess)
-            return; // Let the SignalSender try again later.
-        if (expectedSuccess.value())
-            return; // We've success jettison the codeBlocks.
-    }
-
-    // If we get here, then this SIGTRAP is not due to a VMTrap. Let's do the default action.
-    auto originalAction = originalSigtrapAction.sa_sigaction;
-    if (originalAction) {
-        // It is always safe to just invoke the original handler using the sa_sigaction form
-        // without checking for the SA_SIGINFO flag. If the original handler is of the
-        // sa_handler form, it will just ignore the 2nd and 3rd arguments since sa_handler is a
-        // subset of sa_sigaction. This is what the man pages says the OS does anyway.
-        originalAction(signalNumber, info, uap);
-    }
-    
-    // Pre-emptively restore the default handler but we may roll it back below.
-    struct sigaction currentAction;
-    struct sigaction defaultAction;
-    defaultAction.sa_handler = SIG_DFL;
-    sigfillset(&defaultAction.sa_mask);
-    defaultAction.sa_flags = 0;
-    sigaction(SIGTRAP, &defaultAction, &currentAction);
-    
-    if (currentAction.sa_sigaction != handleSigtrap) {
-        // This means that there's a client handler installed after us. This also means
-        // that the client handler thinks it was able to recover from the SIGTRAP, and
-        // did not uninstall itself. We can't argue with this because the signal isn't
-        // known to be from a VMTraps signal. Hence, restore the client handler
-        // and keep going.
-        sigaction(SIGTRAP, &currentAction, nullptr);
-    }
-}
-
-static void installSignalHandlers()
-{
-    typedef void (* SigactionHandler)(int, siginfo_t *, void *);
-    struct sigaction action;
-
-    action.sa_sigaction = reinterpret_cast<SigactionHandler>(handleSigusr1);
-    sigfillset(&action.sa_mask);
-    action.sa_flags = SA_SIGINFO;
-    sigaction(SIGUSR1, &action, &originalSigusr1Action);
-
-    action.sa_sigaction = reinterpret_cast<SigactionHandler>(handleSigtrap);
-    sigfillset(&action.sa_mask);
-    action.sa_flags = SA_SIGINFO;
-    sigaction(SIGTRAP, &action, &originalSigtrapAction);
+            if (!traps.needTrapHandling())
+                return SignalAction::Handled; // The polling code beat us to handling the trap already.
+
+            auto expectedSuccess = traps.tryJettisonCodeBlocksOnStack(context);
+            if (!expectedSuccess)
+                return SignalAction::Handled; // Let the SignalSender try again later.
+            if (expectedSuccess.value())
+                return SignalAction::Handled; // We've success jettison the codeBlocks.
+        }
+
+        return SignalAction::Handled;
+    });
 }
 
@@ -401 +344 @@
         static std::once_flag once;
         std::call_once(once, [] {
-            installSignalHandlers();
+            installSignalHandler();
         });
     }
@@ -461 +404 @@
             auto optionalOwnerThread = vm.ownerThread();
             if (optionalOwnerThread) {
-                optionalOwnerThread.value()->signal(SIGUSR1);
+                sendMessage(*optionalOwnerThread.value().get(), [] (siginfo_t*, ucontext_t* ucontext) -> void {
+                    SignalContext context(ucontext->uc_mcontext);
+                    auto activeVMAndStackBounds = findActiveVMAndStackBounds(context);
+                    if (activeVMAndStackBounds) {
+                        VM* vm = activeVMAndStackBounds.value().vm;
+                        if (vm) {
+                            StackBounds stackBounds = activeVMAndStackBounds.value().stackBounds;
+                            VMTraps& traps = vm->traps();
+                            if (traps.needTrapHandling())
+                                traps.tryInstallTrapBreakpoints(context, stackBounds);
+                        }
+                    }
+                });
                 break;
             }