Bug 226643

[3/3414] Building CXX object Source/JavaScriptCore/CMakeF...vedSources/unified-sources/UnifiedSource-3a3c4ec0-3.cpp.o In file included from JavaScriptCore/DerivedSources/unified-sources/UnifiedSource-3a3c4ec0-3.cpp:7: ../../Source/JavaScriptCore/jit/JITCall.cpp: In member function ‘void JSC::JIT::compileOpCall(const JSC::Instruction*, unsigned int) [with Op = JSC::OpCallEval]’: ../../Source/JavaScriptCore/jit/JITCall.cpp:256:10: warning: ‘this’ pointer is null [-Wnonnull] 256 | auto slowPaths = info->emitFastPath(*this, regT0, regT2, CallLinkInfo::UseDataIC::Yes); | ^~~~~~~~~ In file included from ../../Source/JavaScriptCore/bytecode/CodeBlock.h:34, from ../../Source/JavaScriptCore/jit/AssemblyHelpers.h:30, from ../../Source/JavaScriptCore/jit/CCallHelpers.h:30, from ../../Source/JavaScriptCore/jit/JITAddGenerator.h:30, from ../../Source/JavaScriptCore/jit/JITAddGenerator.cpp:27, from JavaScriptCore/DerivedSources/unified-sources/UnifiedSource-3a3c4ec0-3.cpp:1: ../../Source/JavaScriptCore/bytecode/CallLinkInfo.h:178:30: note: in a call to non-static member function ‘JSC::AbstractMacroAssembler<JSC::X86Assembler>::JumpList JSC::CallLinkInfo::emitFastPath(JSC::CCallHelpers&, JSC::GPRReg, JSC::GPRReg, JSC::CallLinkInfo::UseDataIC)’ 178 | MacroAssembler::JumpList emitFastPath(CCallHelpers&, GPRReg calleeGPR, GPRReg callLinkInfoGPR, UseDataIC) WARN_UNUSED_RETURN; | ^~~~~~~~~~~~ Despite the very misleading text of the warning, GCC is concerned that *info* may be NULL at JITCall.cpp:256. (It's concerned about the value of 'this' *inside* the call to info->emitFastPath.) Would be great if a JavaScriptCore developer could investigate it, please. From my amateurish read of the code, it sure *looks* like GCC's warning is reasonable as there appear to be codepaths where info is NULL at that point. The warning may be suppressed either with IGNORE_WARNINGS_BEGIN/END or by adding a RELEASE_ASSERT(info).