Bug 202160 – Address static analyzer warnings in DFGSpeculativeJIT64.cpp, FTLLowerDFGToB3.cpp: 1st function call argument is an uninitialized value

• Component: JavaScriptCore
• Status: RESOLVED LATER

[Keith Rollin]

Xcode's static analyzer reports many possible issues like the following:

    .../OpenSource/Source/JavaScriptCore/dfg/DFGSpeculativeJIT64.cpp:2999:13: warning: 1st function call argument is an uninitialized value
                m_jit.add32(argGPRs[0], newValueGPR);
                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


    .../OpenSource/Source/JavaScriptCore/ftl/FTLLowerDFGToB3.cpp:3668:27: warning: 1st function call argument is an uninitialized value
                atomicValue = m_out.atomicXchgAdd(args[0], pointer, width);
                              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

These are false positives. The static analyzer things that argGPRs[0] or args[0] might not be initialized if a certain loop variable happens to be zero. However, the static analyzer doesn't realize that, at any time those array elements are accessed, that loop variable will not be zero. Therefore, the access are OK. Assure the static analyzer of this with some ASSERTs saying that the loop variable is not zero.

[Radar WebKit Bug Importer]

<rdar://problem/55673582>

[Keith Rollin]

Created attachment 379472 [details]
Patch

[Alexey Proskuryakov]

Closing this 5+ years later, as it's an abandoned patch.