[llvm-commits] Question about /llvm/trunk/lib/CodeGen/MachineScheduler.cpp

Mon Feb 6 15:32:14 PST 2012

Hi Sergei,

Please make sure you run with assertions enabled and look at -debug-only=misched output. -verify-machineinstrs may also be useful.

I'm not sure what the problem is, but crashing is bad. If there are any implicit assumptions, then they should be made explicit.

I'm not sure I understand the CFG output. A block should end in a terminator. BB#7 claims to have a successor, but I don't know what it's terminator is.

-Andy

On Feb 6, 2012, at 10:56 AM, Sergei Larin <slarin at codeaurora.org> wrote:

> 
> Andrew, 
> 
>  This is something between a bug report and a question. I do not provide
> enough context to reproduce the failure, but hope it is fresh enough in your
> memory :) 
> 
> In lib/CodeGen/MachineScheduler.cpp
> 
> In bool MachineScheduler::runOnMachineFunction(MachineFunction &mf) {}
> 
> While iterating over following MBB, for the following fragment
> ...
> BB#6: derived from LLVM BB %sw.bb6, ADDRESS TAKEN
>    Predecessors according to CFG: BB#1
>        %vreg10<def> = TFRI 1; IntRegs:%vreg10
>        STrib %vreg1<kill>, 0, %vreg10<kill>; mem:ST1[%Enum_Ref_Par]
> IntRegs:%vreg1,%vreg10
>        JMP <BB#8>
>    Successors according to CFG: BB#8
> 
> BB#7: derived from LLVM BB %sw.bb7, ADDRESS TAKEN
>    Predecessors according to CFG: BB#1
>        %vreg9<def> = TFRI 2; IntRegs:%vreg9
>        STrib %vreg1<kill>, 0, %vreg9<kill>; mem:ST1[%Enum_Ref_Par]
> IntRegs:%vreg1,%vreg9
>    Successors according to CFG: BB#8
> 
> BB#8: derived from LLVM BB %sw.epilog, ADDRESS TAKEN
>    Predecessors according to CFG: BB#0 BB#1 BB#7 BB#6 BB#5 BB#4 BB#2
>        JMPR %PC<imp-def,dead>, %R31<imp-use>, %R0<imp-use,undef>
> ...
> 
> BB#7 seems to cause a problem when iterating over it with RegionEnd pointing
> somewhere wrong. Am I breaking some implicit assumption in BB formation?
> Want MBB->end() suppose to return for the BB#7?
> 
> *** Final schedule ***
> 
> MachineScheduling Proc_6:BB#7
>  From: %vreg9<def> = TFRI 2; IntRegs:%vreg9
>    To:
> Program received signal SIGSEGV, Segmentation fault.
> 0x0000000001a0c814 in llvm::MachineOperand::isReg (this=0x7) at
> /local/mnt/workspace/slarin/tools/llvm-mainline-merged/include/llvm/CodeGen/
> MachineOperand.h:204
> 204       bool isReg() const { return OpKind == MO_Register; }
> (gdb) bt
> #0  0x0000000001a0c814 in llvm::MachineOperand::isReg (this=0x7) at
> /local/mnt/workspace/slarin/tools/llvm-mainline-merged/include/llvm/CodeGen/
> MachineOperand.h:204
> #1  0x00000000021ca720 in llvm::MachineInstr::print (this=0x3e2c9f0, OS=...,
> TM=0x0) at
> /local/mnt/workspace/slarin/tools/llvm-mainline-merged/lib/CodeGen/MachineIn
> str.cpp:1462
> #2  0x0000000001a970fe in llvm::operator<< (OS=..., MI=...) at
> /local/mnt/workspace/slarin/tools/llvm-mainline-merged/include/llvm/CodeGen/
> MachineInstr.h:934
> #3  0x00000000022e4c18 in (anonymous
> namespace)::MachineScheduler::runOnMachineFunction (this=0x3dcc1c0, mf=...)
>    at
> /local/mnt/workspace/slarin/tools/llvm-mainline-merged/lib/CodeGen/MachineSc
> heduler.cpp:297
> #4  0x00000000021c41e5 in llvm::MachineFunctionPass::runOnFunction
> (this=0x3dcc1c0, F=...) at
> /local/mnt/workspace/slarin/tools/llvm-mainline-merged/lib/CodeGen/MachineFu
> nctionPass.cpp:33
> #5  0x0000000002789db6 in llvm::FPPassManager::runOnFunction
> (this=0x3dcb820, F=...) at
> /local/mnt/workspace/slarin/tools/llvm-mainline-merged/lib/VMCore/PassManage
> r.cpp:1498
> #6  0x000000000278a001 in llvm::FPPassManager::runOnModule (this=0x3dcb820,
> M=...) at
> /local/mnt/workspace/slarin/tools/llvm-mainline-merged/lib/VMCore/PassManage
> r.cpp:1520
> #7  0x000000000278a344 in llvm::MPPassManager::runOnModule (this=0x3dc8ec0,
> M=...) at
> /local/mnt/workspace/slarin/tools/llvm-mainline-merged/lib/VMCore/PassManage
> r.cpp:1574
> #8  0x000000000278a85a in llvm::PassManagerImpl::run (this=0x3dc8b70, M=...)
> at
> /local/mnt/workspace/slarin/tools/llvm-mainline-merged/lib/VMCore/PassManage
> r.cpp:1658
> #9  0x000000000278ab55 in llvm::PassManager::run (this=0x3d7f140, M=...) at
> /local/mnt/workspace/slarin/tools/llvm-mainline-merged/lib/VMCore/PassManage
> r.cpp:1687
> #10 0x0000000000c9488d in (anonymous
> namespace)::EmitAssemblyHelper::EmitAssembly (this=0x7fffffffa2e0,
> Action=clang::Backend_EmitAssembly, OS=0x3d13660)
>    at
> /local/mnt/workspace/slarin/tools/llvm-mainline-merged/tools/clang/lib/CodeG
> en/BackendUtil.cpp:497
> #11 0x0000000000c94968 in clang::EmitBackendOutput (Diags=..., CGOpts=...,
> TOpts=..., LOpts=..., M=0x3d1a3c0, Action=clang::Backend_EmitAssembly,
> OS=0x3d13660)
>    at
> /local/mnt/workspace/slarin/tools/llvm-mainline-merged/tools/clang/lib/CodeG
> en/BackendUtil.cpp:509
> #12 0x0000000000c9042c in clang::BackendConsumer::HandleTranslationUnit
> (this=0x3d123a0, C=...)
>    at
> /local/mnt/workspace/slarin/tools/llvm-mainline-merged/tools/clang/lib/CodeG
> en/CodeGenAction.cpp:155
> #13 0x0000000000e3cf61 in clang::ParseAST (S=..., PrintStats=false) at
> /local/mnt/workspace/slarin/tools/llvm-mainline-merged/tools/clang/lib/Parse
> /ParseAST.cpp:110
> #14 0x0000000000b00725 in clang::ASTFrontendAction::ExecuteAction
> (this=0x3cf1740) at
> /local/mnt/workspace/slarin/tools/llvm-mainline-merged/tools/clang/lib/Front
> end/FrontendAction.cpp:414
> #15 0x0000000000c8ef9c in clang::CodeGenAction::ExecuteAction
> (this=0x3cf1740) at
> /local/mnt/workspace/slarin/tools/llvm-mainline-merged/tools/clang/lib/CodeG
> en/CodeGenAction.cpp:407
> #16 0x0000000000b00377 in clang::FrontendAction::Execute (this=0x3cf1740) at
> /local/mnt/workspace/slarin/tools/llvm-mainline-merged/tools/clang/lib/Front
> end/FrontendAction.cpp:334
> #17 0x0000000000ad8e63 in clang::CompilerInstance::ExecuteAction
> (this=0x3ced2d0, Act=...)
>    at
> /local/mnt/workspace/slarin/tools/llvm-mainline-merged/tools/clang/lib/Front
> end/CompilerInstance.cpp:653
> #18 0x0000000000aaa8e4 in clang::ExecuteCompilerInvocation (Clang=0x3ced2d0)
>    at
> /local/mnt/workspace/slarin/tools/llvm-mainline-merged/tools/clang/lib/Front
> endTool/ExecuteCompilerInvocation.cpp:175
> #19 0x0000000000a99618 in cc1_main (ArgBegin=0x7fffffffaf10,
> ArgEnd=0x7fffffffb108, Argv0=0x3cebaf8
> "/prj/qct/sunray-austin/scratch/slarin/qdsp6_hex/bin/qc/bin/clang",
> MainAddr=0xaa4654)
>    at
> /local/mnt/workspace/slarin/tools/llvm-mainline-merged/tools/clang/tools/dri
> ver/cc1_main.cpp:165
> #20 0x0000000000aa5e77 in main (argc_=65, argv_=0x7fffffffc058) at
> /local/mnt/workspace/slarin/tools/llvm-mainline-merged/tools/clang/tools/dri
> ver/driver.cpp:353
> 
> 
> Thanks.
> 
> Sergei
> 