Hi Vangelis, Not sure this will help you, but you can try to compare llvm::MachineInstr::getOpcode() with TargetOpcode::G_LOAD and TargetOpcode::G_STORE if you can obtain a MachineInstr instance. It also may have sense to ask llvm-dev for a proper solution.
From: lldb-dev <lldb-dev-boun...@lists.llvm.org> On Behalf Of Vangelis Tsiatsianas via lldb-dev Sent: Tuesday, November 5, 2019 3:43 PM To: via lldb-dev <lldb-dev@lists.llvm.org> Cc: Vangelis Tsiatsianas <vangeli...@icloud.com> Subject: Re: [lldb-dev] Identifying instructions that definitely access memory Hello, I decided to try once more with a follow-up email, since my previous one got no responses (I hope itโs not considered rude to send more than one message in a row for a particular question). To sum up and clarify my previous question, what I need is a way to track memory stores and save both the old and the new value of the memory location being modified. My thinking so far: 1. Recognize the instructions that definitely access memory before they execute, based on their opcode. 2. Tell whether each operand is a register or a memory location. 3. If itโs a memory location, check whether it is a load or store destination. 4. In case it is a store destination, fetch and save current value from memory. 5. Execute instruction. 6. Fetch and save new value from memory. However, I was not able to find a cross-architecture API that covers all of the conditions above and more specifically Instruction::DoesStore() and Operand::IsStoreDestination(). Last but not least, I should notice that the target is executed in single-step mode, so I do have control right before and after the execution of every instruction. Thanks, again, in advance! ๐ โ Vangelis On 21 Oct 2019, at 08:54, Vangelis Tsiatsianas <vangeli...@icloud.com<mailto:vangeli...@icloud.com>> wrote: Hello, I am looking for a way to identify loads, stores and any other kind of instruction that definitely perform memory access and extract the address operand(s), however I was not able to find a cross-architecture API. The closest I stumbled upon are "MCInstrDesc::mayLoad()" and "MCInstrDesc::mayStore()", but I understand that their results are just a hint, so I would then need to examine the instruction name or opcode in order to find out whether itโs actually a load or store and which operand(s) is (are) memory address(es) and also do so for each architecture separately, which I would really like to avoid. Is there a way to identify such instructions either by examining them through the disassembler (e.g. "DoesLoad()" | "DoesStore()") before they execute or right after they perform any kind of memory access? Thank you very much, in advance! ๐ โ Vangelis
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