Changeset 211684 in webkit for trunk/Source/JavaScriptCore/tools/SigillCrashAnalyzer.cpp

Timestamp:

Feb 5, 2017, 11:26:50 AM (8 years ago)

Author:

[email protected]

Message:

The VMInspector should use an RAII Locker.
​https://bugs.webkit.org/show_bug.cgi?id=167854

Reviewed by Saam Barati.

Previously, VMInspector::lock() was returning an expected LockToken, and there's
no way to unlock it when we're done with it. This was not a problem before
because the VMInspector had only one client, the SigillCrashAnalyzer, that
expected the process to crash due to a SIGILL shortly thereafter.

However, the VMInspector is useful as a debugging tool that we can apply in other
debugging tasks. Fixing VMInspector::lock() to return an RAII locker will enable
other use cases. Plus it's just bad form to be able to lock something and never
be able to unlock it.

• tools/SigillCrashAnalyzer.cpp:

(JSC::SigillCrashAnalyzer::analyze):

• tools/VMInspector.cpp:
• tools/VMInspector.h:

File:

• trunk/Source/JavaScriptCore/tools/SigillCrashAnalyzer.cpp (modified) (2 diffs)

trunk/Source/JavaScriptCore/tools/SigillCrashAnalyzer.cpp

@@ -242 +242 @@
         // Use a timeout period of 2 seconds. The client is about to crash, and we don't
         // want to turn the crash into a hang by re-trying the lock for too long.
-        auto expectedLockToken = inspector.lock(Seconds(2));
-        if (!expectedLockToken) {
-            ASSERT(expectedLockToken.error() == VMInspector::Error::TimedOut);
+        auto expectedLocker = inspector.lock(Seconds(2));
+        if (!expectedLocker) {
+            ASSERT(expectedLocker.error() == VMInspector::Error::TimedOut);
             log("ERROR: Unable to analyze SIGILL. Timed out while waiting to iterate VMs.");
             return;
         }
-        auto lockToken = expectedLockToken.value();
+        auto& locker = expectedLocker.value();
 
         void* pc = context.machinePC;
-        auto isInJITMemory = inspector.isValidExecutableMemory(lockToken, pc);
+        auto isInJITMemory = inspector.isValidExecutableMemory(locker, pc);
         if (!isInJITMemory) {
             log("ERROR: Timed out: not able to determine if pc %p is in valid JIT executable memory", pc);
@@ -275 +275 @@
 #endif
 
-        auto expectedCodeBlock = inspector.codeBlockForMachinePC(lockToken, pc);
+        auto expectedCodeBlock = inspector.codeBlockForMachinePC(locker, pc);
         if (!expectedCodeBlock) {
             if (expectedCodeBlock.error() == VMInspector::Error::TimedOut)