[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@cisco.com>
Co-authored-by: Nikola Prica <nikola.prica@rt-rk.com>
Co-authored-by: Ivan Baev <ibaev@cisco.com>

Differential Revision: https://reviews.llvm.org/D61062

llvm-svn: 364536

llvm/include/llvm/CodeGen/MachineFunction.h

@@ -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);
 };
 
 //===--------------------------------------------------------------------===//

llvm/lib/CodeGen/InlineSpiller.cpp

@@ -868,6 +868,8 @@ foldMemoryOperand(ArrayRef<std::pair<MachineInstr *, unsigned>> Ops,
       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.

llvm/lib/CodeGen/LiveRangeEdit.cpp

@@ -232,6 +232,8 @@ bool LiveRangeEdit::foldAsLoad(LiveInterval *LI,
   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;

llvm/lib/CodeGen/MachineFunction.cpp

@@ -363,6 +363,13 @@ MachineInstr &MachineFunction::CloneMachineInstrBundle(MachineBasicBlock &MBB,
 /// ~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::addCodeViewHeapAllocSite(MachineInstr *I, MDNode *MD) {
   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;
+}
+
 /// \}
 
 //===----------------------------------------------------------------------===//

llvm/lib/CodeGen/MachineOutliner.cpp

@@ -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

llvm/lib/CodeGen/PeepholeOptimizer.cpp

@@ -1777,6 +1777,8 @@ bool PeepholeOptimizer::runOnMachineFunction(MachineFunction &MF) {
               LocalMIs.erase(MI);
               LocalMIs.erase(DefMI);
               LocalMIs.insert(FoldMI);
+              if (MI->isCall())
+                MI->getMF()->updateCallSiteInfo(MI, FoldMI);
               MI->eraseFromParent();
               DefMI->eraseFromParent();
               MRI->markUsesInDebugValueAsUndef(FoldedReg);

llvm/lib/CodeGen/TargetInstrInfo.cpp

@@ -137,8 +137,14 @@ TargetInstrInfo::ReplaceTailWithBranchTo(MachineBasicBlock::iterator Tail,
   // 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))

llvm/lib/CodeGen/XRayInstrumentation.cpp

@@ -110,6 +110,8 @@ void XRayInstrumentation::replaceRetWithPatchableRet(
         for (auto &MO : T.operands())
           MIB.add(MO);
         Terminators.push_back(&T);
+        if (T.isCall())
+          MF.updateCallSiteInfo(&T);
       }
     }
   }

llvm/lib/Target/X86/X86ExpandPseudo.cpp

@@ -270,6 +270,7 @@ bool X86ExpandPseudo::ExpandMI(MachineBasicBlock &MBB,
 
     MachineInstr &NewMI = *std::prev(MBBI);
     NewMI.copyImplicitOps(*MBBI->getParent()->getParent(), *MBBI);
+    MBB.getParent()->updateCallSiteInfo(&*MBBI, &NewMI);
 
     // Delete the pseudo instruction TCRETURN.
     MBB.erase(MBBI);