[llvm] r364536 - [Backend] Keep call site info valid through the backend

Finkel, Hal J. via llvm-commits llvm-commits at lists.llvm.org
Thu Jun 27 09:02:09 PDT 2019


It looks like we've just introduces a new invariant that must be 
maintained by MI passes. Please send a note to llvm-dev to warn target 
maintainers (including out-of-tree-target developers) and add something 
about this in the release notes.

Thanks again,

Hal

On 6/27/19 8:10 AM, Djordje Todorovic via llvm-commits wrote:
> Author: djtodoro
> Date: Thu Jun 27 06:10:29 2019
> New Revision: 364536
>
> URL: http://llvm.org/viewvc/llvm-project?rev=364536&view=rev
> Log:
> [Backend] Keep call site info valid through the backend
>
> Handle call instruction replacements and deletions in order to preserve
> valid state of the call site info of the MachineFunction.
>
> NOTE: If the call site info is enabled for a new target, the assertion from
> the MachineFunction::DeleteMachineInstr() should help to locate places
> where the updateCallSiteInfo() should be called in order to preserve valid
> state of the call site info.
>
> ([10/13] Introduce the debug entry values.)
>
> Co-authored-by: Ananth Sowda <asowda at cisco.com>
> Co-authored-by: Nikola Prica <nikola.prica at rt-rk.com>
> Co-authored-by: Ivan Baev <ibaev at cisco.com>
>
> Differential Revision: https://reviews.llvm.org/D61062
>
> Modified:
>      llvm/trunk/include/llvm/CodeGen/MachineFunction.h
>      llvm/trunk/lib/CodeGen/InlineSpiller.cpp
>      llvm/trunk/lib/CodeGen/LiveRangeEdit.cpp
>      llvm/trunk/lib/CodeGen/MachineFunction.cpp
>      llvm/trunk/lib/CodeGen/MachineOutliner.cpp
>      llvm/trunk/lib/CodeGen/PeepholeOptimizer.cpp
>      llvm/trunk/lib/CodeGen/TargetInstrInfo.cpp
>      llvm/trunk/lib/CodeGen/XRayInstrumentation.cpp
>      llvm/trunk/lib/Target/X86/X86ExpandPseudo.cpp
>
> Modified: llvm/trunk/include/llvm/CodeGen/MachineFunction.h
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/MachineFunction.h?rev=364536&r1=364535&r2=364536&view=diff
> ==============================================================================
> --- llvm/trunk/include/llvm/CodeGen/MachineFunction.h (original)
> +++ llvm/trunk/include/llvm/CodeGen/MachineFunction.h Thu Jun 27 06:10:29 2019
> @@ -976,6 +976,12 @@ public:
>       return CallSitesInfo;
>     }
>   
> +  /// Update call sites info by deleting entry for \p Old call instruction.
> +  /// If \p New is present then transfer \p Old call info to it. This function
> +  /// should be called before removing call instruction or before replacing
> +  /// call instruction with new one.
> +  void updateCallSiteInfo(const MachineInstr *Old,
> +                          const MachineInstr *New = nullptr);
>   };
>   
>   //===--------------------------------------------------------------------===//
>
> Modified: llvm/trunk/lib/CodeGen/InlineSpiller.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/InlineSpiller.cpp?rev=364536&r1=364535&r2=364536&view=diff
> ==============================================================================
> --- llvm/trunk/lib/CodeGen/InlineSpiller.cpp (original)
> +++ llvm/trunk/lib/CodeGen/InlineSpiller.cpp Thu Jun 27 06:10:29 2019
> @@ -868,6 +868,8 @@ foldMemoryOperand(ArrayRef<std::pair<Mac
>         HSpiller.rmFromMergeableSpills(*MI, FI))
>       --NumSpills;
>     LIS.ReplaceMachineInstrInMaps(*MI, *FoldMI);
> +  if (MI->isCall())
> +    MI->getMF()->updateCallSiteInfo(MI, FoldMI);
>     MI->eraseFromParent();
>   
>     // Insert any new instructions other than FoldMI into the LIS maps.
>
> Modified: llvm/trunk/lib/CodeGen/LiveRangeEdit.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/LiveRangeEdit.cpp?rev=364536&r1=364535&r2=364536&view=diff
> ==============================================================================
> --- llvm/trunk/lib/CodeGen/LiveRangeEdit.cpp (original)
> +++ llvm/trunk/lib/CodeGen/LiveRangeEdit.cpp Thu Jun 27 06:10:29 2019
> @@ -232,6 +232,8 @@ bool LiveRangeEdit::foldAsLoad(LiveInter
>     LLVM_DEBUG(dbgs() << "                folded: " << *FoldMI);
>     LIS.ReplaceMachineInstrInMaps(*UseMI, *FoldMI);
>     UseMI->eraseFromParent();
> +  if (UseMI->isCall())
> +    UseMI->getMF()->updateCallSiteInfo(UseMI, FoldMI);
>     DefMI->addRegisterDead(LI->reg, nullptr);
>     Dead.push_back(DefMI);
>     ++NumDCEFoldedLoads;
>
> Modified: llvm/trunk/lib/CodeGen/MachineFunction.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/MachineFunction.cpp?rev=364536&r1=364535&r2=364536&view=diff
> ==============================================================================
> --- llvm/trunk/lib/CodeGen/MachineFunction.cpp (original)
> +++ llvm/trunk/lib/CodeGen/MachineFunction.cpp Thu Jun 27 06:10:29 2019
> @@ -363,6 +363,13 @@ MachineInstr &MachineFunction::CloneMach
>   /// ~MachineInstr() destructor must be empty.
>   void
>   MachineFunction::DeleteMachineInstr(MachineInstr *MI) {
> +  // Verify that a call site info is at valid state. This assertion should
> +  // be triggered during the implementation of support for the
> +  // call site info of a new architecture. If the assertion is triggered,
> +  // back trace will tell where to insert a call to updateCallSiteInfo().
> +  assert((!MI->isCall(MachineInstr::IgnoreBundle) ||
> +          CallSitesInfo.find(MI) == CallSitesInfo.end()) &&
> +         "Call site info was not updated!");
>     // Strip it for parts. The operand array and the MI object itself are
>     // independently recyclable.
>     if (MI->Operands)
> @@ -826,6 +833,22 @@ void MachineFunction::addCodeViewHeapAll
>     CodeViewHeapAllocSites.push_back(std::make_tuple(BeginLabel, EndLabel, DI));
>   }
>   
> +void MachineFunction::updateCallSiteInfo(const MachineInstr *Old,
> +                                         const MachineInstr *New) {
> +  if (!Target.Options.EnableDebugEntryValues || Old == New)
> +    return;
> +
> +  assert(Old->isCall() && (!New || New->isCall()) &&
> +         "Call site info referes only to call instructions!");
> +  CallSiteInfoMap::iterator CSIt = CallSitesInfo.find(Old);
> +  if (CSIt == CallSitesInfo.end())
> +    return;
> +  CallSiteInfo CSInfo = std::move(CSIt->second);
> +  CallSitesInfo.erase(CSIt);
> +  if (New)
> +    CallSitesInfo[New] = CSInfo;
> +}
> +
>   /// \}
>   
>   //===----------------------------------------------------------------------===//
>
> Modified: llvm/trunk/lib/CodeGen/MachineOutliner.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/MachineOutliner.cpp?rev=364536&r1=364535&r2=364536&view=diff
> ==============================================================================
> --- llvm/trunk/lib/CodeGen/MachineOutliner.cpp (original)
> +++ llvm/trunk/lib/CodeGen/MachineOutliner.cpp Thu Jun 27 06:10:29 2019
> @@ -1245,8 +1245,9 @@ bool MachineOutliner::outline(Module &M,
>         if (MBB.getParent()->getProperties().hasProperty(
>                 MachineFunctionProperties::Property::TracksLiveness)) {
>           // Helper lambda for adding implicit def operands to the call
> -        // instruction.
> -        auto CopyDefs = [&CallInst](MachineInstr &MI) {
> +        // instruction. It also updates call site information for moved
> +        // code.
> +        auto CopyDefsAndUpdateCalls = [&CallInst](MachineInstr &MI) {
>             for (MachineOperand &MOP : MI.operands()) {
>               // Skip over anything that isn't a register.
>               if (!MOP.isReg())
> @@ -1258,13 +1259,16 @@ bool MachineOutliner::outline(Module &M,
>                     MOP.getReg(), true, /* isDef = true */
>                     true /* isImp = true */));
>             }
> +          if (MI.isCall())
> +            MI.getMF()->updateCallSiteInfo(&MI);
>           };
>           // Copy over the defs in the outlined range.
>           // First inst in outlined range <-- Anything that's defined in this
>           // ...                           .. range has to be added as an
>           // implicit Last inst in outlined range  <-- def to the call
> -        // instruction.
> -        std::for_each(CallInst, std::next(EndIt), CopyDefs);
> +        // instruction. Also remove call site information for outlined block
> +        // of code.
> +        std::for_each(CallInst, std::next(EndIt), CopyDefsAndUpdateCalls);
>         }
>   
>         // Erase from the point after where the call was inserted up to, and
>
> Modified: llvm/trunk/lib/CodeGen/PeepholeOptimizer.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/PeepholeOptimizer.cpp?rev=364536&r1=364535&r2=364536&view=diff
> ==============================================================================
> --- llvm/trunk/lib/CodeGen/PeepholeOptimizer.cpp (original)
> +++ llvm/trunk/lib/CodeGen/PeepholeOptimizer.cpp Thu Jun 27 06:10:29 2019
> @@ -1777,6 +1777,8 @@ bool PeepholeOptimizer::runOnMachineFunc
>                 LocalMIs.erase(MI);
>                 LocalMIs.erase(DefMI);
>                 LocalMIs.insert(FoldMI);
> +              if (MI->isCall())
> +                MI->getMF()->updateCallSiteInfo(MI, FoldMI);
>                 MI->eraseFromParent();
>                 DefMI->eraseFromParent();
>                 MRI->markUsesInDebugValueAsUndef(FoldedReg);
>
> Modified: llvm/trunk/lib/CodeGen/TargetInstrInfo.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/TargetInstrInfo.cpp?rev=364536&r1=364535&r2=364536&view=diff
> ==============================================================================
> --- llvm/trunk/lib/CodeGen/TargetInstrInfo.cpp (original)
> +++ llvm/trunk/lib/CodeGen/TargetInstrInfo.cpp Thu Jun 27 06:10:29 2019
> @@ -137,8 +137,14 @@ TargetInstrInfo::ReplaceTailWithBranchTo
>     // Save off the debug loc before erasing the instruction.
>     DebugLoc DL = Tail->getDebugLoc();
>   
> -  // Remove all the dead instructions from the end of MBB.
> -  MBB->erase(Tail, MBB->end());
> +  // Update call site info and remove all the dead instructions
> +  // from the end of MBB.
> +  while (Tail != MBB->end()) {
> +    auto MI = Tail++;
> +    if (MI->isCall())
> +      MBB->getParent()->updateCallSiteInfo(&*MI);
> +    MBB->erase(MI);
> +  }
>   
>     // If MBB isn't immediately before MBB, insert a branch to it.
>     if (++MachineFunction::iterator(MBB) != MachineFunction::iterator(NewDest))
>
> Modified: llvm/trunk/lib/CodeGen/XRayInstrumentation.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/XRayInstrumentation.cpp?rev=364536&r1=364535&r2=364536&view=diff
> ==============================================================================
> --- llvm/trunk/lib/CodeGen/XRayInstrumentation.cpp (original)
> +++ llvm/trunk/lib/CodeGen/XRayInstrumentation.cpp Thu Jun 27 06:10:29 2019
> @@ -110,6 +110,8 @@ void XRayInstrumentation::replaceRetWith
>           for (auto &MO : T.operands())
>             MIB.add(MO);
>           Terminators.push_back(&T);
> +        if (T.isCall())
> +          MF.updateCallSiteInfo(&T);
>         }
>       }
>     }
>
> Modified: llvm/trunk/lib/Target/X86/X86ExpandPseudo.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ExpandPseudo.cpp?rev=364536&r1=364535&r2=364536&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Target/X86/X86ExpandPseudo.cpp (original)
> +++ llvm/trunk/lib/Target/X86/X86ExpandPseudo.cpp Thu Jun 27 06:10:29 2019
> @@ -270,6 +270,7 @@ bool X86ExpandPseudo::ExpandMI(MachineBa
>   
>       MachineInstr &NewMI = *std::prev(MBBI);
>       NewMI.copyImplicitOps(*MBBI->getParent()->getParent(), *MBBI);
> +    MBB.getParent()->updateCallSiteInfo(&*MBBI, &NewMI);
>   
>       // Delete the pseudo instruction TCRETURN.
>       MBB.erase(MBBI);
>
>
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-- 
Hal Finkel
Lead, Compiler Technology and Programming Languages
Leadership Computing Facility
Argonne National Laboratory



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