[llvm-dev] Using BuildMI to insert Intel MPX instruction BNDCU failed

Youren Shen via llvm-dev llvm-dev at lists.llvm.org
Sun Jul 1 23:45:31 PDT 2018


Hi, Craig,

Thanks for your reply, that's really helpful. I reviewed my code and find
it's actually the error of an Add insertion.
It's so obsure for me to construct an instruction with BuildMI. Although
there is a little description on code generator[1]. But the example is not
enough for a starter to learn how to add operands. I have learned that
using llvm-mc can tell u how to construct a instruction. like below:

echo "add r10, r11" | llvm-mc -x86-asm-syntax=intel -output-asm-variant=1
-show-inst
        .text
        add     r10, r11                # <MCInst #206 ADD64rr
                                        #  <MCOperand Reg:123>
                                        #  <MCOperand Reg:123>
                                        #  <MCOperand Reg:124>>
I believe put some words about how the construct instruction at [1] will be
really helpful.

what's the meaning of members in llvm:RegStates? like Define, Undefine,
Implicit, Dead or use, what's their present at target codes?

I really appreciate for all the help and reply.
Thank you very much.
ref:
[1]. https://llvm.org/docs/CodeGenerator.html#id23

On Mon, Jul 2, 2018 at 1:53 AM Craig Topper <craig.topper at gmail.com> wrote:

> Also shouldn't, BND2 be a use not a def. The instruction takes a BND
> register and a GPR as inputs. It's output is to signal #BR if the check
> fails.
>
>
> ~Craig
>
>
> On Sun, Jul 1, 2018 at 10:41 AM Craig Topper <craig.topper at gmail.com>
> wrote:
>
>> BNDCU shouldn't be printing more than 2 operands.
>>
>> On trunk right now, it uses case 4 for the first fragment (operand 1).
>> Case 1 for the second fragment (a comma and a space). And fragment 2 for
>> the third fragment (operand 0).
>>
>> Are you using trunk or an earlier version?
>>
>> ~Craig
>>
>>
>> On Sun, Jul 1, 2018 at 10:14 AM Youren Shen via llvm-dev <
>> llvm-dev at lists.llvm.org> wrote:
>>
>>> Hello everyone, I'm a newbie of llvm. I'm trying to insert Intel MPX
>>> instruction BNDCU with BuildMI. I add my machinefunctionpass
>>> at addPreEmitPass2.
>>> Here is the code of insertion:
>>>
>>> BuildMI(MBB, MI, DL, TII->get(X86::BNDCU64rr)).addReg(X86::BND2,
>>> RegState::Define).addReg(X86::R10);
>>>
>>> And here is to stack track  when I compiler program with modified llc:
>>> /home/shenyouren/workspace/build-llvm/bin/llc -o obj/simple.s
>>> obj/simple-opt.bc
>>> llc: /home/shenyouren/workspace/llvm/include/llvm/ADT/SmallVector.h:154:
>>> const T& llvm::SmallVectorTemplateCommon<T, <template-parameter-1-2>
>>> >::operator[](llvm::SmallVectorTemplateCommon<T, <template-parameter-1-2>
>>> >::size_type) const [with T = llvm::MCOperand; <template-parameter-1-2> =
>>> void; llvm::SmallVectorTemplateCommon<T, <template-parameter-1-2>
>>> >::const_reference = const llvm::MCOperand&;
>>> llvm::SmallVectorTemplateCommon<T, <template-parameter-1-2> >::size_type =
>>> long unsigned int]: Assertion `idx < size()' failed.
>>> Stack dump:
>>> 0.      Program arguments: /home/shenyouren/workspace/build-llvm/bin/llc
>>> -o obj/simple.s obj/simple-opt.bc
>>> 1.      Running pass 'Function Pass Manager' on module
>>> 'obj/simple-opt.bc'.
>>> 2.      Running pass 'X86 Assembly Printer' on function '@main'
>>> #0 0x0000000003879bdf llvm::sys::PrintStackTrace(llvm::raw_ostream&)
>>> /home/shenyouren/workspace/llvm/lib/Support/Unix/Signals.inc:398:0
>>> #1 0x0000000003879c72 PrintStackTraceSignalHandler(void*)
>>> /home/shenyouren/workspace/llvm/lib/Support/Unix/Signals.inc:462:0
>>> #2 0x0000000003877e5b llvm::sys::RunSignalHandlers()
>>> /home/shenyouren/workspace/llvm/lib/Support/Signals.cpp:49:0
>>> #3 0x0000000003879454 SignalHandler(int)
>>> /home/shenyouren/workspace/llvm/lib/Support/Unix/Signals.inc:252:0
>>> #4 0x00007fcc8f4c9390 __restore_rt
>>> (/lib/x86_64-linux-gnu/libpthread.so.0+0x11390)
>>> #5 0x00007fcc8e67e428 gsignal (/lib/x86_64-linux-gnu/libc.so.6+0x35428)
>>> #6 0x00007fcc8e68002a abort (/lib/x86_64-linux-gnu/libc.so.6+0x3702a)
>>> #7 0x00007fcc8e676bd7 (/lib/x86_64-linux-gnu/libc.so.6+0x2dbd7)
>>> #8 0x00007fcc8e676c82 (/lib/x86_64-linux-gnu/libc.so.6+0x2dc82)
>>> #9 0x00000000016b63bb llvm::SmallVectorTemplateCommon<llvm::MCOperand,
>>> void>::operator[](unsigned long) const
>>> /home/shenyouren/workspace/llvm/include/llvm/ADT/SmallVector.h:154:0
>>> #10 0x00000000016b63bb llvm::MCInst::getOperand(unsigned int) const
>>> /home/shenyouren/workspace/llvm/include/llvm/MC/MCInst.h:182:0
>>> #11 0x00000000026695fd
>>> llvm::X86ATTInstPrinter::printOperand(llvm::MCInst const*, unsigned int,
>>> llvm::raw_ostream&)
>>> /home/shenyouren/workspace/llvm/lib/Target/X86/InstPrinter/X86ATTInstPrinter.cpp:185:0
>>> #12 0x0000000002664c06
>>> llvm::X86ATTInstPrinter::printInstruction(llvm::MCInst const*,
>>> llvm::raw_ostream&)
>>> /home/shenyouren/workspace/build-llvm/lib/Target/X86/X86GenAsmWriter.inc:48204:0
>>> #13 0x0000000002668edc llvm::X86ATTInstPrinter::printInst(llvm::MCInst
>>> const*, llvm::raw_ostream&, llvm::StringRef, llvm::MCSubtargetInfo const&)
>>> /home/shenyouren/workspace/llvm/lib/Target/X86/InstPrinter/X86ATTInstPrinter.cpp:89:0
>>> #14 0x00000000031d5811
>>> llvm::MCTargetStreamer::prettyPrintAsm(llvm::MCInstPrinter&,
>>> llvm::raw_ostream&, llvm::MCInst const&, llvm::MCSubtargetInfo const&)
>>> /home/shenyouren/workspace/llvm/lib/MC/MCStreamer.cpp:856:0
>>> #15 0x00000000031690e2 (anonymous
>>> namespace)::MCAsmStreamer::EmitInstruction(llvm::MCInst const&,
>>> llvm::MCSubtargetInfo const&, bool)
>>> /home/shenyouren/workspace/llvm/lib/MC/MCAsmStreamer.cpp:1752:0
>>> #16 0x0000000002355fdf
>>> llvm::X86AsmPrinter::EmitAndCountInstruction(llvm::MCInst&)
>>> /home/shenyouren/workspace/llvm/lib/Target/X86/X86MCInstLower.cpp:107:0
>>> #17 0x0000000002360ae9
>>> llvm::X86AsmPrinter::EmitInstruction(llvm::MachineInstr const*)
>>> /home/shenyouren/workspace/llvm/lib/Target/X86/X86MCInstLower.cpp:2604:0
>>> #18 0x000000000292e629 llvm::AsmPrinter::EmitFunctionBody()
>>> /home/shenyouren/workspace/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp:1086:0
>>> #19 0x0000000002352908
>>> llvm::X86AsmPrinter::runOnMachineFunction(llvm::MachineFunction&)
>>> /home/shenyouren/workspace/llvm/lib/Target/X86/X86AsmPrinter.cpp:79:0
>>> #20 0x0000000002bc6afa
>>> llvm::MachineFunctionPass::runOnFunction(llvm::Function&)
>>> /home/shenyouren/workspace/llvm/lib/CodeGen/MachineFunctionPass.cpp:62:0
>>> #21 0x000000000307eeac
>>> llvm::FPPassManager::runOnFunction(llvm::Function&)
>>> /home/shenyouren/workspace/llvm/lib/IR/LegacyPassManager.cpp:1520:0
>>> #22 0x000000000307f045 llvm::FPPassManager::runOnModule(llvm::Module&)
>>> /home/shenyouren/workspace/llvm/lib/IR/LegacyPassManager.cpp:1541:0
>>> #23 0x000000000307f3c0 (anonymous
>>> namespace)::MPPassManager::runOnModule(llvm::Module&)
>>> /home/shenyouren/workspace/llvm/lib/IR/LegacyPassManager.cpp:1597:0
>>> #24 0x000000000307fad5 llvm::legacy::PassManagerImpl::run(llvm::Module&)
>>> /home/shenyouren/workspace/llvm/lib/IR/LegacyPassManager.cpp:1700:0
>>> #25 0x000000000307fce1 llvm::legacy::PassManager::run(llvm::Module&)
>>> /home/shenyouren/workspace/llvm/lib/IR/LegacyPassManager.cpp:1732:0
>>> #26 0x00000000013e9361 compileModule(char**, llvm::LLVMContext&)
>>> /home/shenyouren/workspace/llvm/tools/llc/llc.cpp:575:0
>>> #27 0x00000000013e7a6d main
>>> /home/shenyouren/workspace/llvm/tools/llc/llc.cpp:345:0
>>> #28 0x00007fcc8e669830 __libc_start_main
>>> (/lib/x86_64-linux-gnu/libc.so.6+0x20830)
>>> #29 0x00000000013e5779 _start
>>> (/home/shenyouren/workspace/build-llvm/bin/llc+0x13e5779)
>>> Makefile:25: recipe for target 'obj/simple.s' failed
>>>
>>> I have checked X86ATTInstPrinter::printInstruction(llvm::MCInst const*,
>>> llvm::raw_ostream&)
>>> /home/shenyouren/workspace/build-llvm/lib/Target/X86/X86GenAsmWriter.inc:48204,
>>> and it will invoke printOperand(MI, 2, O); And I guess the BNDCU only have
>>> 2 operand, that's why it failed.
>>> But I don't know how to fix it.
>>> Is there anyone know how to solve this problem? I really appreciate for
>>> any help!
>>> --
>>> Best Regards.
>>> Youren Shen
>>> _______________________________________________
>>> LLVM Developers mailing list
>>> llvm-dev at lists.llvm.org
>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>>
>> --
Best Regards.
Youren Shen
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