macOS / iOS JavaScriptCore - Loop-Invariant Code Motion (LICM) Leaves Object Property Access Unguarded

While fuzzing JavaScriptCore, I encountered the following modified and commented JavaScript program which crashes jsc from current HEAD and release /System/Library/Frameworks/JavaScriptCore.framework/Resources/jsc: function v2trigger // Force JIT compilation. for let v7 = 0; v7 1000000; v7++ if...

macOS iOS JavaScriptCore - Loop-Invariant Code Motion (LICM) Leaves Object Property Access Unguarded

macOS iOS JavaScriptCore - Loop-Invariant Code Motion LICM Leaves Object Property Access Unguarded While fuzzing JavaScriptCore, I encountered the following modified and commented JavaScript program which crashes jsc from current HEAD and release...

macOS / iOS JavaScriptCore - Loop-Invariant Code Motion (LICM) Leaves Object Property Access Unguard

macOS / iOS JavaScriptCore - Loop-Invariant Code Motion LICM Leaves Object Property Access Unguarded While fuzzing JavaScriptCore, I encountered the following modified and commented JavaScript program which crashes jsc from current HEAD and release...

Apple macOS < 10.14.5 / iOS < 12.3 JavaScriptCore - Loop-Invariant Code Motion (LICM) in DFG JIT Leaves Stack Variable Uninitialized

While fuzzing JavaScriptCore, I encountered the following modified and commented JavaScript program which crashes jsc from current HEAD and release: // Run with --useConcurrentJIT=false // Fill the stack with the return value of the provided function. function stacksprayf // This function will...

macOS < 10.14.5 / iOS < 12.3 JavaScriptCore - Loop-Invariant Code Motion (LICM) in DFG JIT

macOS 13.37; stackspray = ; for let v15 = 0; v15 100; v15++ function v19v23 // This weird loop form might be required to prevent loop unrolling... for let v30 = 0; v30 3; v30 = v30 + "asdf" // Generates the specific CFG necessary to trigger the bug. const v33 = Error != Error; if v33 else // Forc...

Apple macOS 10.14.5 iOS 12.3 JavaScriptCore - Loop-Invariant Code Motion (LICM) in DFG JIT Leaves Stack Variable Uninitialized

Apple macOS 10.14.5 iOS 12.3 JavaScriptCore - Loop-Invariant Code Motion LICM in DFG JIT Leaves Stack Variable Uninitialized While fuzzing JavaScriptCore, I encountered the following modified and commented JavaScript program which crashes jsc from current HEAD and release: // Run with...