Reland "[DwarfDebug] Dump call site debug info"

The build failure found after the rL365467 has been
resolved.

Differential Revision: https://reviews.llvm.org/D60716

llvm-svn: 367446

llvm/docs/LangRef.rst

@@ -4769,6 +4769,10 @@ The current supported opcode vocabulary is limited:
   ``DW_OP_entry_value`` may also appear after the ``AsmPrinter`` pass when
   a call site parameter value (``DW_AT_call_site_parameter_value``)
   is represented as entry value of the parameter.
+- ``DW_OP_breg`` (or ``DW_OP_bregx``) represents a content on the provided
+  signed offset of the specified register. The opcode is only generated by the
+  ``AsmPrinter`` pass to describe call site parameter value which requires an
+  expression over two registers.
 
 DWARF specifies three kinds of simple location descriptions: Register, memory,
 and implicit location descriptions.  Note that a location description is

llvm/include/llvm/CodeGen/TargetInstrInfo.h

@@ -60,6 +60,8 @@ class TargetSubtargetInfo;
 
 template <class T> class SmallVectorImpl;
 
+using ParamLoadedValue = std::pair<const MachineOperand*, DIExpression*>;
+
 //---------------------------------------------------------------------------
 ///
 /// TargetInstrInfo - Interface to description of machine instruction set
@@ -1691,6 +1693,11 @@ public:
     return false;
   }
 
+  /// Produce the expression describing the \p MI loading a value into
+  /// the parameter's forwarding register.
+  virtual Optional<ParamLoadedValue>
+  describeLoadedValue(const MachineInstr &MI) const;
+
 private:
   unsigned CallFrameSetupOpcode, CallFrameDestroyOpcode;
   unsigned CatchRetOpcode;

llvm/include/llvm/CodeGen/TargetRegisterInfo.h

@@ -535,6 +535,11 @@ public:
     return false;
   }
 
+  /// This is a wrapper around getCallPreservedMask().
+  /// Return true if the register is preserved after the call.
+  virtual bool isCalleeSavedPhysReg(unsigned PhysReg,
+                                    const MachineFunction &MF) const;
+
   /// Prior to adding the live-out mask to a stackmap or patchpoint
   /// instruction, provide the target the opportunity to adjust it (mainly to
   /// remove pseudo-registers that should be ignored).

llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp

@@ -892,32 +892,106 @@ void DwarfCompileUnit::constructAbstractSubprogramScopeDIE(
     ContextCU->addDIEEntry(*AbsDef, dwarf::DW_AT_object_pointer, *ObjectPointer);
 }
 
-DIE &DwarfCompileUnit::constructCallSiteEntryDIE(DIE &ScopeDIE,
+dwarf::Tag DwarfCompileUnit::getDwarf5OrGNUCallSiteTag(dwarf::Tag Tag) const {
-                                                 const DISubprogram &CalleeSP,
+  bool ApplyGNUExtensions = DD->getDwarfVersion() == 4 && DD->tuneForGDB();
-                                                 bool IsTail,
+  if (!ApplyGNUExtensions)
-                                                 const MCExpr *PCOffset) {
+    return Tag;
+  switch (Tag) {
+  case dwarf::DW_TAG_call_site:
+    return dwarf::DW_TAG_GNU_call_site;
+  case dwarf::DW_TAG_call_site_parameter:
+    return dwarf::DW_TAG_GNU_call_site_parameter;
+  default:
+    llvm_unreachable("unhandled call site tag");
+  }
+}
+
+dwarf::Attribute
+DwarfCompileUnit::getDwarf5OrGNUCallSiteAttr(dwarf::Attribute Attr) const {
+  bool ApplyGNUExtensions = DD->getDwarfVersion() == 4 && DD->tuneForGDB();
+  if (!ApplyGNUExtensions)
+    return Attr;
+  switch (Attr) {
+  case dwarf::DW_AT_call_all_calls:
+    return dwarf::DW_AT_GNU_all_call_sites;
+  case dwarf::DW_AT_call_target:
+    return dwarf::DW_AT_GNU_call_site_target;
+  case dwarf::DW_AT_call_origin:
+    return dwarf::DW_AT_abstract_origin;
+  case dwarf::DW_AT_call_pc:
+    return dwarf::DW_AT_low_pc;
+  case dwarf::DW_AT_call_value:
+    return dwarf::DW_AT_GNU_call_site_value;
+  case dwarf::DW_AT_call_tail_call:
+    return dwarf::DW_AT_GNU_tail_call;
+  default:
+    llvm_unreachable("unhandled call site attribute");
+  }
+}
+
+DIE &DwarfCompileUnit::constructCallSiteEntryDIE(
+    DIE &ScopeDIE, const DISubprogram *CalleeSP, bool IsTail,
+    const MCSymbol *PCAddr, const MCExpr *PCOffset, unsigned CallReg) {
   // Insert a call site entry DIE within ScopeDIE.
-  DIE &CallSiteDIE =
+  DIE &CallSiteDIE = createAndAddDIE(
-      createAndAddDIE(dwarf::DW_TAG_call_site, ScopeDIE, nullptr);
+      getDwarf5OrGNUCallSiteTag(dwarf::DW_TAG_call_site), ScopeDIE, nullptr);
 
-  // For the purposes of showing tail call frames in backtraces, a key piece of
+  if (CallReg) {
-  // information is DW_AT_call_origin, a pointer to the callee DIE.
+    // Indirect call.
-  DIE *CalleeDIE = getOrCreateSubprogramDIE(&CalleeSP);
+    addAddress(CallSiteDIE,
-  assert(CalleeDIE && "Could not create DIE for call site entry origin");
+               getDwarf5OrGNUCallSiteAttr(dwarf::DW_AT_call_target),
-  addDIEEntry(CallSiteDIE, dwarf::DW_AT_call_origin, *CalleeDIE);
+               MachineLocation(CallReg));
-
-  if (IsTail) {
-    // Attach DW_AT_call_tail_call to tail calls for standards compliance.
-    addFlag(CallSiteDIE, dwarf::DW_AT_call_tail_call);
   } else {
+    DIE *CalleeDIE = getOrCreateSubprogramDIE(CalleeSP);
+    assert(CalleeDIE && "Could not create DIE for call site entry origin");
+    addDIEEntry(CallSiteDIE,
+                getDwarf5OrGNUCallSiteAttr(dwarf::DW_AT_call_origin),
+                *CalleeDIE);
+  }
+
+  if (IsTail)
+    // Attach DW_AT_call_tail_call to tail calls for standards compliance.
+    addFlag(CallSiteDIE,
+            getDwarf5OrGNUCallSiteAttr(dwarf::DW_AT_call_tail_call));
+
   // Attach the return PC to allow the debugger to disambiguate call paths
   // from one function to another.
+  if (DD->getDwarfVersion() == 4 && DD->tuneForGDB()) {
+    assert(PCAddr && "Missing PC information for a call");
+    addLabelAddress(CallSiteDIE, dwarf::DW_AT_low_pc, PCAddr);
+  } else if (!IsTail || DD->tuneForGDB()) {
     assert(PCOffset && "Missing return PC information for a call");
     addAddressExpr(CallSiteDIE, dwarf::DW_AT_call_return_pc, PCOffset);
   }
+
   return CallSiteDIE;
 }
 
+void DwarfCompileUnit::constructCallSiteParmEntryDIEs(
+    DIE &CallSiteDIE, SmallVector<DbgCallSiteParam, 4> &Params) {
+  for (const auto &Param : Params) {
+    unsigned Register = Param.getRegister();
+    auto CallSiteDieParam =
+        DIE::get(DIEValueAllocator,
+                 getDwarf5OrGNUCallSiteTag(dwarf::DW_TAG_call_site_parameter));
+    insertDIE(CallSiteDieParam);
+    addAddress(*CallSiteDieParam, dwarf::DW_AT_location,
+               MachineLocation(Register));
+
+    DIELoc *Loc = new (DIEValueAllocator) DIELoc;
+    DIEDwarfExpression DwarfExpr(*Asm, *this, *Loc);
+    DwarfExpr.setCallSiteParamValueFlag();
+
+    DwarfDebug::emitDebugLocValue(*Asm, nullptr, Param.getValue(), DwarfExpr);
+
+    addBlock(*CallSiteDieParam,
+             getDwarf5OrGNUCallSiteAttr(dwarf::DW_AT_call_value),
+             DwarfExpr.finalize());
+
+    CallSiteDIE.addChild(CallSiteDieParam);
+  }
+}
+
 DIE *DwarfCompileUnit::constructImportedEntityDIE(
     const DIImportedEntity *Module) {
   DIE *IMDie = DIE::get(DIEValueAllocator, (dwarf::Tag)Module->getTag());

llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h

@@ -227,12 +227,33 @@ public:
 
   void constructAbstractSubprogramScopeDIE(LexicalScope *Scope);
 
+  /// This takes the official DWARF 5 tag and returns the appropriate
+  /// GNU tag if needed.
+  dwarf::Tag getDwarf5OrGNUCallSiteTag(dwarf::Tag Tag) const;
+  /// This takes the official DWARF 5 attribute and returns the appropriate
+  /// GNU attribute if needed.
+  dwarf::Attribute getDwarf5OrGNUCallSiteAttr(dwarf::Attribute Attr) const;
+
   /// Construct a call site entry DIE describing a call within \p Scope to a
-  /// callee described by \p CalleeSP. \p IsTail specifies whether the call is
+  /// callee described by \p CalleeSP.
-  /// a tail call. \p PCOffset must be non-zero for non-tail calls or be the
+  /// \p IsTail specifies whether the call is a tail call.
+  /// \p PCAddr (used for GDB + DWARF 4 tuning) points to the PC value after
+  /// the call instruction.
+  /// \p PCOffset (used for cases other than GDB + DWARF 4 tuning) must be
+  /// non-zero for non-tail calls (in the case of non-gdb tuning, since for
+  /// GDB + DWARF 5 tuning we still generate PC info for tail calls) or be the
   /// function-local offset to PC value after the call instruction.
-  DIE &constructCallSiteEntryDIE(DIE &ScopeDIE, const DISubprogram &CalleeSP,
+  /// \p CallReg is a register location for an indirect call. For direct calls
-                                 bool IsTail, const MCExpr *PCOffset);
+  /// the \p CallReg is set to 0.
+  DIE &constructCallSiteEntryDIE(DIE &ScopeDIE, const DISubprogram *CalleeSP,
+                                 bool IsTail, const MCSymbol *PCAddr,
+                                 const MCExpr *PCOffset, unsigned CallReg);
+  /// Construct call site parameter DIEs for the \p CallSiteDIE. The \p Params
+  /// were collected by the \ref collectCallSiteParameters.
+  /// Note: The order of parameters does not matter, since debuggers recognize
+  ///       call site parameters by the DW_AT_location attribute.
+  void constructCallSiteParmEntryDIEs(DIE &CallSiteDIE,
+                                      SmallVector<DbgCallSiteParam, 4> &Params);
 
   /// Construct import_module DIE.
   DIE *constructImportedEntityDIE(const DIImportedEntity *Module);

llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp

@@ -26,6 +26,7 @@
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/Statistic.h"
 #include "llvm/ADT/Triple.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/BinaryFormat/Dwarf.h"
@@ -39,6 +40,7 @@
 #include "llvm/CodeGen/MachineModuleInfo.h"
 #include "llvm/CodeGen/MachineOperand.h"
 #include "llvm/CodeGen/TargetInstrInfo.h"
+#include "llvm/CodeGen/TargetLowering.h"
 #include "llvm/CodeGen/TargetRegisterInfo.h"
 #include "llvm/CodeGen/TargetSubtargetInfo.h"
 #include "llvm/DebugInfo/DWARF/DWARFExpression.h"
@@ -83,6 +85,8 @@ using namespace llvm;
 
 #define DEBUG_TYPE "dwarfdebug"
 
+STATISTIC(NumCSParams, "Number of dbg call site params created");
+
 static cl::opt<bool>
 DisableDebugInfoPrinting("disable-debug-info-print", cl::Hidden,
                          cl::desc("Disable debug info printing"));
@@ -551,6 +555,146 @@ void DwarfDebug::constructAbstractSubprogramScopeDIE(DwarfCompileUnit &SrcCU,
   }
 }
 
+/// Try to interpret values loaded into registers that forward parameters
+/// for \p CallMI. Store parameters with interpreted value into \p Params.
+static void collectCallSiteParameters(const MachineInstr *CallMI,
+                                      ParamSet &Params) {
+  auto *MF = CallMI->getMF();
+  auto CalleesMap = MF->getCallSitesInfo();
+  auto CallFwdRegsInfo = CalleesMap.find(CallMI);
+
+  // There is no information for the call instruction.
+  if (CallFwdRegsInfo == CalleesMap.end())
+    return;
+
+  auto *MBB = CallMI->getParent();
+  const auto &TRI = MF->getSubtarget().getRegisterInfo();
+  const auto &TII = MF->getSubtarget().getInstrInfo();
+  const auto &TLI = MF->getSubtarget().getTargetLowering();
+
+  // Skip the call instruction.
+  auto I = std::next(CallMI->getReverseIterator());
+
+  DenseSet<unsigned> ForwardedRegWorklist;
+  // Add all the forwarding registers into the ForwardedRegWorklist.
+  for (auto ArgReg : CallFwdRegsInfo->second) {
+    bool InsertedReg = ForwardedRegWorklist.insert(ArgReg.Reg).second;
+    assert(InsertedReg && "Single register used to forward two arguments?");
+  }
+
+  // We erase, from the ForwardedRegWorklist, those forwarding registers for
+  // which we successfully describe a loaded value (by using
+  // the describeLoadedValue()). For those remaining arguments in the working
+  // list, for which we do not describe a loaded value by
+  // the describeLoadedValue(), we try to generate an entry value expression
+  // for their call site value desctipion, if the call is within the entry MBB.
+  // The RegsForEntryValues maps a forwarding register into the register holding
+  // the entry value.
+  // TODO: Handle situations when call site parameter value can be described
+  // as the entry value within basic blocks other then the first one.
+  bool ShouldTryEmitEntryVals = MBB->getIterator() == MF->begin();
+  DenseMap<unsigned, unsigned> RegsForEntryValues;
+
+  // If the MI is an instruction defining a parameter's forwarding register,
+  // add it into the Defs. If the MI clobbers more then one register, we use
+  // the Defs in order to remove all the registers from
+  // the ForwardedRegWorklist, since we do not support such situations now.
+  auto getForwardingRegsDefinedByMI = [&](const MachineInstr &MI,
+                                         SmallVectorImpl<unsigned> &Defs) {
+    if (MI.isDebugInstr())
+      return;
+
+    for (const MachineOperand &MO : MI.operands()) {
+      if (MO.isReg() && MO.isDef() && TRI->isPhysicalRegister(MO.getReg())) {
+        for (auto FwdReg : ForwardedRegWorklist) {
+          if (TRI->regsOverlap(FwdReg, MO.getReg())) {
+            Defs.push_back(FwdReg);
+            break;
+          }
+        }
+      }
+    }
+  };
+
+  auto finishCallSiteParam = [&](DbgValueLoc DbgLocVal, unsigned Reg) {
+    unsigned FwdReg = Reg;
+    if (ShouldTryEmitEntryVals) {
+      auto EntryValReg = RegsForEntryValues.find(Reg);
+      if (EntryValReg != RegsForEntryValues.end())
+        FwdReg = EntryValReg->second;
+    }
+
+    DbgCallSiteParam CSParm(FwdReg, DbgLocVal);
+    Params.push_back(CSParm);
+    ++NumCSParams;
+  };
+
+  // Search for a loading value in forwaring registers.
+  for (; I != MBB->rend(); ++I) {
+    // If the next instruction is a call we can not interpret parameter's
+    // forwarding registers or we finished the interpretation of all parameters.
+    if (I->isCall())
+      return;
+
+    if (ForwardedRegWorklist.empty())
+      return;
+
+    SmallVector<unsigned, 4> Defs;
+    getForwardingRegsDefinedByMI(*I, Defs);
+    if (Defs.empty())
+      continue;
+
+    // If the MI clobbers more then one forwarding register we must remove
+    // all of them from the working list.
+    for (auto Reg : Defs)
+      ForwardedRegWorklist.erase(Reg);
+    if (I->getNumDefs() != 1)
+      continue;
+    unsigned Reg = Defs[0];
+
+    if (auto ParamValue = TII->describeLoadedValue(*I)) {
+      if (ParamValue->first->isImm()) {
+        unsigned Val = ParamValue->first->getImm();
+        DbgValueLoc DbgLocVal(ParamValue->second, Val);
+        finishCallSiteParam(DbgLocVal, Reg);
+      } else if (ParamValue->first->isReg()) {
+        unsigned RegLoc = ParamValue->first->getReg();
+        unsigned SP = TLI->getStackPointerRegisterToSaveRestore();
+        unsigned FP = TRI->getFrameRegister(*MF);
+        bool IsSPorFP = (RegLoc == SP) || (RegLoc == FP);
+        if (TRI->isCalleeSavedPhysReg(RegLoc, *MF) || IsSPorFP) {
+          DbgValueLoc DbgLocVal(ParamValue->second,
+                                MachineLocation(RegLoc,
+                                                /*IsIndirect=*/IsSPorFP));
+          finishCallSiteParam(DbgLocVal, Reg);
+        } else if (ShouldTryEmitEntryVals) {
+          ForwardedRegWorklist.insert(RegLoc);
+          RegsForEntryValues[RegLoc] = Reg;
+        }
+      }
+    }
+  }
+
+  // Emit the call site parameter's value as an entry value.
+  if (ShouldTryEmitEntryVals) {
+    // Create an entry value expression where the expression following
+    // the 'DW_OP_entry_value' will be the size of 1 (a register operation).
+    DIExpression *EntryExpr = DIExpression::get(MF->getFunction().getContext(),
+                                                {dwarf::DW_OP_entry_value, 1});
+    for (auto RegEntry : ForwardedRegWorklist) {
+      unsigned FwdReg = RegEntry;
+      auto EntryValReg = RegsForEntryValues.find(RegEntry);
+        if (EntryValReg != RegsForEntryValues.end())
+          FwdReg = EntryValReg->second;
+
+      DbgValueLoc DbgLocVal(EntryExpr, MachineLocation(RegEntry));
+      DbgCallSiteParam CSParm(FwdReg, DbgLocVal);
+      Params.push_back(CSParm);
+      ++NumCSParams;
+    }
+  }
+}
+
 void DwarfDebug::constructCallSiteEntryDIEs(const DISubprogram &SP,
                                             DwarfCompileUnit &CU, DIE &ScopeDIE,
                                             const MachineFunction &MF) {
@@ -563,10 +707,12 @@ void DwarfDebug::constructCallSiteEntryDIEs(const DISubprogram &SP,
   // for both tail and non-tail calls. Don't use DW_AT_call_all_source_calls
   // because one of its requirements is not met: call site entries for
   // optimized-out calls are elided.
-  CU.addFlag(ScopeDIE, dwarf::DW_AT_call_all_calls);
+  CU.addFlag(ScopeDIE,
+             CU.getDwarf5OrGNUCallSiteAttr(dwarf::DW_AT_call_all_calls));
 
   const TargetInstrInfo *TII = MF.getSubtarget().getInstrInfo();
   assert(TII && "TargetInstrInfo not found: cannot label tail calls");
+  bool ApplyGNUExtensions = getDwarfVersion() == 4 && tuneForGDB();
 
   // Emit call site entries for each call or tail call in the function.
   for (const MachineBasicBlock &MBB : MF) {
@@ -581,30 +727,66 @@ void DwarfDebug::constructCallSiteEntryDIEs(const DISubprogram &SP,
         return;
 
       // If this is a direct call, find the callee's subprogram.
+      // In the case of an indirect call find the register that holds
+      // the callee.
       const MachineOperand &CalleeOp = MI.getOperand(0);
-      if (!CalleeOp.isGlobal())
+      if (!CalleeOp.isGlobal() && !CalleeOp.isReg())
-        continue;
-      const Function *CalleeDecl = dyn_cast<Function>(CalleeOp.getGlobal());
-      if (!CalleeDecl || !CalleeDecl->getSubprogram())
         continue;
 
+      unsigned CallReg = 0;
+      const DISubprogram *CalleeSP = nullptr;
+      const Function *CalleeDecl = nullptr;
+      if (CalleeOp.isReg()) {
+        CallReg = CalleeOp.getReg();
+        if (!CallReg)
+          continue;
+      } else {
+        CalleeDecl = dyn_cast<Function>(CalleeOp.getGlobal());
+        if (!CalleeDecl || !CalleeDecl->getSubprogram())
+          continue;
+        CalleeSP = CalleeDecl->getSubprogram();
+      }
+
       // TODO: Omit call site entries for runtime calls (objc_msgSend, etc).
-      // TODO: Add support for indirect calls.
 
       bool IsTail = TII->isTailCall(MI);
 
-      // For tail calls, no return PC information is needed. For regular calls,
+      // For tail calls, for non-gdb tuning, no return PC information is needed.
-      // the return PC is needed to disambiguate paths in the call graph which
+      // For regular calls (and tail calls in GDB tuning), the return PC
-      // could lead to some target function.
+      // is needed to disambiguate paths in the call graph which could lead to
+      // some target function.
       const MCExpr *PCOffset =
-          IsTail ? nullptr : getFunctionLocalOffsetAfterInsn(&MI);
+          (IsTail && !tuneForGDB()) ? nullptr
+                                    : getFunctionLocalOffsetAfterInsn(&MI);
+
+      // Address of a call-like instruction for a normal call or a jump-like
+      // instruction for a tail call. This is needed for GDB + DWARF 4 tuning.
+      const MCSymbol *PCAddr =
+          ApplyGNUExtensions ? const_cast<MCSymbol*>(getLabelAfterInsn(&MI))
+                             : nullptr;
+
+      assert((IsTail || PCOffset || PCAddr) &&
+             "Call without return PC information");
 
-      assert((IsTail || PCOffset) && "Call without return PC information");
       LLVM_DEBUG(dbgs() << "CallSiteEntry: " << MF.getName() << " -> "
-                        << CalleeDecl->getName() << (IsTail ? " [tail]" : "")
+                        << (CalleeDecl ? CalleeDecl->getName()
-                        << "\n");
+                                       : StringRef(MF.getSubtarget()
-      CU.constructCallSiteEntryDIE(ScopeDIE, *CalleeDecl->getSubprogram(),
+                                                       .getRegisterInfo()
-                                   IsTail, PCOffset);
+                                                       ->getName(CallReg)))
+                        << (IsTail ? " [IsTail]" : "") << "\n");
+
+      DIE &CallSiteDIE =
+            CU.constructCallSiteEntryDIE(ScopeDIE, CalleeSP, IsTail, PCAddr,
+                                         PCOffset, CallReg);
+
+      // For now only GDB supports call site parameter debug info.
+      if (Asm->TM.Options.EnableDebugEntryValues &&
+          tuneForGDB()) {
+        ParamSet Params;
+        // Try to interpret values of call site parameters.
+        collectCallSiteParameters(&MI, Params);
+        CU.constructCallSiteParmEntryDIEs(CallSiteDIE, Params);
+      }
     }
   }
 }

llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h

@@ -254,6 +254,25 @@ public:
   }
 };
 
+/// Used for tracking debug info about call site parameters.
+class DbgCallSiteParam {
+private:
+  unsigned Register; ///< Parameter register at the callee entry point.
+  DbgValueLoc Value; ///< Corresponding location for the parameter value at
+                     ///< the call site.
+public:
+  DbgCallSiteParam(unsigned Reg, DbgValueLoc Val)
+      : Register(Reg), Value(Val) {
+    assert(Reg && "Parameter register cannot be undef");
+  }
+
+  unsigned getRegister() const { return Register; }
+  DbgValueLoc getValue() const { return Value; }
+};
+
+/// Collection used for storing debug call site parameters.
+using ParamSet = SmallVector<DbgCallSiteParam, 4>;
+
 /// Helper used to pair up a symbol and its DWARF compile unit.
 struct SymbolCU {
   SymbolCU(DwarfCompileUnit *CU, const MCSymbol *Sym) : Sym(Sym), CU(CU) {}

llvm/lib/CodeGen/AsmPrinter/DwarfExpression.cpp

@@ -241,15 +241,19 @@ bool DwarfExpression::addMachineRegExpression(const TargetRegisterInfo &TRI,
     return false;
   }
 
-  // Handle simple register locations.
+  // Handle simple register locations. If we are supposed to emit
-  if (!isMemoryLocation() && !HasComplexExpression) {
+  // a call site parameter expression and if that expression is just a register
+  // location, emit it with addBReg and offset 0, because we should emit a DWARF
+  // expression representing a value, rather than a location.
+  if (!isMemoryLocation() && !HasComplexExpression && (!isParameterValue() ||
+                                                       isEntryValue())) {
     for (auto &Reg : DwarfRegs) {
       if (Reg.DwarfRegNo >= 0)
         addReg(Reg.DwarfRegNo, Reg.Comment);
       addOpPiece(Reg.Size);
     }
 
-    if (isEntryValue() && DwarfVersion >= 4)
+    if (isEntryValue() && !isParameterValue() && DwarfVersion >= 4)
       emitOp(dwarf::DW_OP_stack_value);
 
     DwarfRegs.clear();
@@ -340,7 +344,17 @@ void DwarfExpression::addExpression(DIExpressionCursor &&ExprCursor,
 
   while (ExprCursor) {
     auto Op = ExprCursor.take();
-    switch (Op->getOp()) {
+    uint64_t OpNum = Op->getOp();
+
+    if (OpNum >= dwarf::DW_OP_reg0 && OpNum <= dwarf::DW_OP_reg31) {
+      emitOp(OpNum);
+      continue;
+    } else if (OpNum >= dwarf::DW_OP_breg0 && OpNum <= dwarf::DW_OP_breg31) {
+      addBReg(OpNum - dwarf::DW_OP_breg0, Op->getArg(0));
+      continue;
+    }
+
+    switch (OpNum) {
     case dwarf::DW_OP_LLVM_fragment: {
       unsigned SizeInBits = Op->getArg(1);
       unsigned FragmentOffset = Op->getArg(0);
@@ -389,7 +403,7 @@ void DwarfExpression::addExpression(DIExpressionCursor &&ExprCursor,
     case dwarf::DW_OP_lit0:
     case dwarf::DW_OP_not:
     case dwarf::DW_OP_dup:
-      emitOp(Op->getOp());
+      emitOp(OpNum);
       break;
     case dwarf::DW_OP_deref:
       assert(!isRegisterLocation());
@@ -458,12 +472,21 @@ void DwarfExpression::addExpression(DIExpressionCursor &&ExprCursor,
     case dwarf::DW_OP_LLVM_tag_offset:
       TagOffset = Op->getArg(0);
       break;
+    case dwarf::DW_OP_regx:
+      emitOp(dwarf::DW_OP_regx);
+      emitUnsigned(Op->getArg(0));
+      break;
+    case dwarf::DW_OP_bregx:
+      emitOp(dwarf::DW_OP_bregx);
+      emitUnsigned(Op->getArg(0));
+      emitSigned(Op->getArg(1));
+      break;
     default:
       llvm_unreachable("unhandled opcode found in expression");
     }
   }
 
-  if (isImplicitLocation())
+  if (isImplicitLocation() && !isParameterValue())
     // Turn this into an implicit location description.
     addStackValue();
 }

llvm/lib/CodeGen/AsmPrinter/DwarfExpression.h

@@ -120,7 +120,7 @@ protected:
   enum { Unknown = 0, Register, Memory, Implicit };
 
   /// The flags of location description being produced.
-  enum { EntryValue = 1 };
+  enum { EntryValue = 1, CallSiteParamValue };
 
   unsigned LocationKind : 3;
   unsigned LocationFlags : 2;
@@ -147,6 +147,10 @@ public:
     return LocationFlags & EntryValue;
   }
 
+  bool isParameterValue() {
+    return LocationFlags & CallSiteParamValue;
+  }
+
   Optional<uint8_t> TagOffset;
 
 protected:
@@ -264,6 +268,11 @@ public:
     LocationFlags |= EntryValue;
   }
 
+  /// Lock this down to become a call site parameter location.
+  void setCallSiteParamValueFlag() {
+    LocationFlags |= CallSiteParamValue;
+  }
+
   /// Emit a machine register location. As an optimization this may also consume
   /// the prefix of a DwarfExpression if a more efficient representation for
   /// combining the register location and the first operation exists.

llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp

@@ -205,6 +205,10 @@ void DwarfUnit::insertDIE(const DINode *Desc, DIE *D) {
   MDNodeToDieMap.insert(std::make_pair(Desc, D));
 }
 
+void DwarfUnit::insertDIE(DIE *D) {
+  MDNodeToDieMap.insert(std::make_pair(nullptr, D));
+}
+
 void DwarfUnit::addFlag(DIE &Die, dwarf::Attribute Attribute) {
   if (DD->getDwarfVersion() >= 4)
     Die.addValue(DIEValueAllocator, Attribute, dwarf::DW_FORM_flag_present,

llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h

@@ -127,6 +127,8 @@ public:
   /// the mappings are kept in DwarfDebug.
   void insertDIE(const DINode *Desc, DIE *D);
 
+  void insertDIE(DIE *D);
+
   /// Add a flag that is true to the DIE.
   void addFlag(DIE &Die, dwarf::Attribute Attribute);
 

llvm/lib/CodeGen/TargetInstrInfo.cpp

@@ -23,6 +23,7 @@
 #include "llvm/CodeGen/TargetRegisterInfo.h"
 #include "llvm/CodeGen/TargetSchedule.h"
 #include "llvm/IR/DataLayout.h"
+#include "llvm/IR/DebugInfoMetadata.h"
 #include "llvm/MC/MCAsmInfo.h"
 #include "llvm/MC/MCInstrItineraries.h"
 #include "llvm/Support/CommandLine.h"
@@ -1120,6 +1121,36 @@ bool TargetInstrInfo::hasLowDefLatency(const TargetSchedModel &SchedModel,
   return (DefCycle != -1 && DefCycle <= 1);
 }
 
+Optional<ParamLoadedValue>
+TargetInstrInfo::describeLoadedValue(const MachineInstr &MI) const {
+  const MachineFunction *MF = MI.getMF();
+  const MachineOperand *Op = nullptr;
+  DIExpression *Expr = DIExpression::get(MF->getFunction().getContext(), {});;
+  const MachineOperand *SrcRegOp, *DestRegOp;
+
+  if (isCopyInstr(MI, SrcRegOp, DestRegOp)) {
+    Op = SrcRegOp;
+    return ParamLoadedValue(Op, Expr);
+  } else if (MI.isMoveImmediate()) {
+    Op = &MI.getOperand(1);
+    return ParamLoadedValue(Op, Expr);
+  } else if (MI.hasOneMemOperand()) {
+    int64_t Offset;
+    const auto &TRI = MF->getSubtarget().getRegisterInfo();
+    const auto &TII = MF->getSubtarget().getInstrInfo();
+    const MachineOperand *BaseOp;
+
+    if (!TII->getMemOperandWithOffset(MI, BaseOp, Offset, TRI))
+      return None;
+
+    Expr = DIExpression::prepend(Expr, DIExpression::DerefAfter, Offset);
+    Op = BaseOp;
+    return ParamLoadedValue(Op, Expr);
+  }
+
+  return None;
+}
+
 /// Both DefMI and UseMI must be valid.  By default, call directly to the
 /// itinerary. This may be overriden by the target.
 int TargetInstrInfo::getOperandLatency(const InstrItineraryData *ItinData,

llvm/lib/CodeGen/TargetRegisterInfo.cpp

@@ -433,6 +433,19 @@ TargetRegisterInfo::getRegAllocationHints(unsigned VirtReg,
   return false;
 }
 
+bool TargetRegisterInfo::isCalleeSavedPhysReg(
+    unsigned PhysReg, const MachineFunction &MF) const {
+  if (PhysReg == 0)
+    return false;
+  const uint32_t *callerPreservedRegs =
+      getCallPreservedMask(MF, MF.getFunction().getCallingConv());
+  if (callerPreservedRegs) {
+    assert(isPhysicalRegister(PhysReg) && "Expected physical register");
+    return (callerPreservedRegs[PhysReg / 32] >> PhysReg % 32) & 1;
+  }
+  return false;
+}
+
 bool TargetRegisterInfo::canRealignStack(const MachineFunction &MF) const {
   return !MF.getFunction().hasFnAttribute("no-realign-stack");
 }

llvm/lib/DebugInfo/DWARF/DWARFDie.cpp

@@ -733,6 +733,7 @@ bool DWARFAttribute::mayHaveLocationDescription(dwarf::Attribute Attr) {
   case DW_AT_call_data_value:
   // Extensions.
   case DW_AT_GNU_call_site_value:
+  case DW_AT_GNU_call_site_target:
     return true;
   default:
     return false;

llvm/lib/IR/DebugInfoMetadata.cpp

@@ -828,15 +828,23 @@ DIExpression *DIExpression::getImpl(LLVMContext &Context,
 }
 
 unsigned DIExpression::ExprOperand::getSize() const {
-  switch (getOp()) {
+  uint64_t Op = getOp();
+
+  if (Op >= dwarf::DW_OP_breg0 && Op <= dwarf::DW_OP_breg31)
+    return 2;
+
+  switch (Op) {
   case dwarf::DW_OP_LLVM_convert:
   case dwarf::DW_OP_LLVM_fragment:
+  case dwarf::DW_OP_bregx:
     return 3;
   case dwarf::DW_OP_constu:
+  case dwarf::DW_OP_consts:
   case dwarf::DW_OP_deref_size:
   case dwarf::DW_OP_plus_uconst:
   case dwarf::DW_OP_LLVM_tag_offset:
   case dwarf::DW_OP_entry_value:
+  case dwarf::DW_OP_regx:
     return 2;
   default:
     return 1;
@@ -849,8 +857,13 @@ bool DIExpression::isValid() const {
     if (I->get() + I->getSize() > E->get())
       return false;
 
+    uint64_t Op = I->getOp();
+    if ((Op >= dwarf::DW_OP_reg0 && Op <= dwarf::DW_OP_reg31) ||
+        (Op >= dwarf::DW_OP_breg0 && Op <= dwarf::DW_OP_breg31))
+      return true;
+
     // Check that the operand is valid.
-    switch (I->getOp()) {
+    switch (Op) {
     default:
       return false;
     case dwarf::DW_OP_LLVM_fragment:
@@ -905,6 +918,8 @@ bool DIExpression::isValid() const {
     case dwarf::DW_OP_lit0:
     case dwarf::DW_OP_not:
     case dwarf::DW_OP_dup:
+    case dwarf::DW_OP_regx:
+    case dwarf::DW_OP_bregx:
       break;
     }
   }

llvm/lib/Target/X86/X86InstrInfo.cpp

@@ -30,7 +30,7 @@
 #include "llvm/CodeGen/StackMaps.h"
 #include "llvm/IR/DerivedTypes.h"
 #include "llvm/IR/Function.h"
-#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/DebugInfoMetadata.h"
 #include "llvm/MC/MCAsmInfo.h"
 #include "llvm/MC/MCExpr.h"
 #include "llvm/MC/MCInst.h"
@@ -7367,6 +7367,92 @@ bool X86InstrInfo::isAssociativeAndCommutative(const MachineInstr &Inst) const {
   }
 }
 
+Optional<ParamLoadedValue>
+X86InstrInfo::describeLoadedValue(const MachineInstr &MI) const {
+  const MachineOperand *Op = nullptr;
+  DIExpression *Expr = nullptr;
+
+  switch (MI.getOpcode()) {
+  case X86::LEA32r:
+  case X86::LEA64r:
+  case X86::LEA64_32r: {
+    // Operand 4 could be global address. For now we do not support
+    // such situation.
+    if (!MI.getOperand(4).isImm() || !MI.getOperand(2).isImm())
+      return None;
+
+    const MachineOperand &Op1 = MI.getOperand(1);
+    const MachineOperand &Op2 = MI.getOperand(3);
+    const TargetRegisterInfo *TRI = &getRegisterInfo();
+    assert(Op2.isReg() &&
+           (Op2.getReg() == X86::NoRegister ||
+            TargetRegisterInfo::isPhysicalRegister(Op2.getReg())));
+
+    // Omit situations like:
+    // %rsi = lea %rsi, 4, ...
+    if ((Op1.isReg() && Op1.getReg() == MI.getOperand(0).getReg()) ||
+        Op2.getReg() == MI.getOperand(0).getReg())
+      return None;
+    else if ((Op1.isReg() && Op1.getReg() != X86::NoRegister &&
+              TRI->regsOverlap(Op1.getReg(), MI.getOperand(0).getReg())) ||
+             (Op2.getReg() != X86::NoRegister &&
+              TRI->regsOverlap(Op2.getReg(), MI.getOperand(0).getReg())))
+      return None;
+
+    int64_t Coef = MI.getOperand(2).getImm();
+    int64_t Offset = MI.getOperand(4).getImm();
+    SmallVector<uint64_t, 8> Ops;
+
+    if ((Op1.isReg() && Op1.getReg() != X86::NoRegister)) {
+      Op = &Op1;
+    } else if (Op1.isFI())
+      Op = &Op1;
+
+    if (Op && Op->isReg() && Op->getReg() == Op2.getReg() && Coef > 0) {
+      Ops.push_back(dwarf::DW_OP_constu);
+      Ops.push_back(Coef + 1);
+      Ops.push_back(dwarf::DW_OP_mul);
+    } else {
+      if (Op && Op2.getReg() != X86::NoRegister) {
+        int dwarfReg = TRI->getDwarfRegNum(Op2.getReg(), false);
+        if (dwarfReg < 0)
+          return None;
+        else if (dwarfReg < 32) {
+          Ops.push_back(dwarf::DW_OP_breg0 + dwarfReg);
+          Ops.push_back(0);
+        } else {
+          Ops.push_back(dwarf::DW_OP_bregx);
+          Ops.push_back(dwarfReg);
+          Ops.push_back(0);
+        }
+      } else if (!Op) {
+        assert(Op2.getReg() != X86::NoRegister);
+        Op = &Op2;
+      }
+
+      if (Coef > 1) {
+        assert(Op2.getReg() != X86::NoRegister);
+        Ops.push_back(dwarf::DW_OP_constu);
+        Ops.push_back(Coef);
+        Ops.push_back(dwarf::DW_OP_mul);
+      }
+
+      if (((Op1.isReg() && Op1.getReg() != X86::NoRegister) || Op1.isFI()) &&
+          Op2.getReg() != X86::NoRegister) {
+        Ops.push_back(dwarf::DW_OP_plus);
+      }
+    }
+
+    DIExpression::appendOffset(Ops, Offset);
+    Expr = DIExpression::get(MI.getMF()->getFunction().getContext(), Ops);
+
+    return ParamLoadedValue(Op, Expr);;
+  }
+  default:
+    return TargetInstrInfo::describeLoadedValue(MI);
+  }
+}
+
 /// This is an architecture-specific helper function of reassociateOps.
 /// Set special operand attributes for new instructions after reassociation.
 void X86InstrInfo::setSpecialOperandAttr(MachineInstr &OldMI1,

llvm/lib/Target/X86/X86InstrInfo.h

@@ -527,6 +527,9 @@ public:
 #define GET_INSTRINFO_HELPER_DECLS
 #include "X86GenInstrInfo.inc"
 
+  Optional<ParamLoadedValue>
+  describeLoadedValue(const MachineInstr &MI) const override;
+
 protected:
   /// Commutes the operands in the given instruction by changing the operands
   /// order and/or changing the instruction's opcode and/or the immediate value

llvm/test/DebugInfo/MIR/X86/dbgcall-site-interpretation.mir

@@ -0,0 +1,202 @@
+# RUN: llc -debug-entry-values -start-after=machineverifier -filetype=obj %s -o -| llvm-dwarfdump -| FileCheck %s
+#
+# CHECK:        DW_TAG_GNU_call_site
+# CHECK-NEXT:     DW_AT_abstract_origin {{.*}} "foo"
+# CHECK-NEXT:     DW_AT_low_pc
+# CHECK-EMPTY:
+# CHECK-NEXT:     DW_TAG_GNU_call_site_parameter
+# CHECK-NEXT:       DW_AT_location      (DW_OP_reg2 RCX)
+# CHECK-NEXT:       DW_AT_GNU_call_site_value   (DW_OP_breg14 R14+0)
+# CHECK-EMPTY: 
+# CHECK-NEXT:     DW_TAG_GNU_call_site_parameter
+# CHECK-NEXT:       DW_AT_location      (DW_OP_reg1 RDX)
+# CHECK-NEXT:       DW_AT_GNU_call_site_value   (DW_OP_fbreg +8)
+# CHECK-EMPTY: 
+# CHECK-NEXT:     DW_TAG_GNU_call_site_parameter
+# CHECK-NEXT:       DW_AT_location      (DW_OP_reg5 RDI)
+# CHECK-NEXT:       DW_AT_GNU_call_site_value   (DW_OP_GNU_entry_value(DW_OP_reg4 RSI))
+# CHECK-EMPTY:
+# CHECK:        DW_TAG_GNU_call_site
+# CHECK-NEXT:     DW_AT_abstract_origin {{.*}}"foo"
+# CHECK-NEXT:     DW_AT_low_pc
+# CHECK-EMPTY:
+# CHECK-NEXT:     DW_TAG_GNU_call_site_parameter
+# CHECK-NEXT:       DW_AT_location      (DW_OP_reg2 RCX)
+# CHECK-NEXT:       DW_AT_GNU_call_site_value   (DW_OP_fbreg +8, DW_OP_deref)
+# CHECK-EMPTY:
+# CHECK-NEXT:     DW_TAG_GNU_call_site_parameter
+# CHECK-NEXT:       DW_AT_location      (DW_OP_reg4 RSI)
+# CHECK-NEXT:       DW_AT_GNU_call_site_value   (DW_OP_lit4)
+# CHECK-EMPTY:
+# CHECK-NOT:      DW_TAG_GNU_call_site_parameter
+#
+# Check that call site interpretation analysis can interpret instructions such
+# as move immediate, register to register moves, stack loading and LEA
+# instructions. Last negative check should verify that we are not producing
+# interpretation for RDX register since its loaded value is call clobberable.
+# Also check that we are generating proper call site debug entities.
+--- |
+  ; ModuleID = 'dbgcall-site-interpretation.c'
+  source_filename = "dbgcall-site-interpretation.c"
+  target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+  target triple = "x86_64-unknown-linux-gnu"
+  
+  ; Function Attrs: nounwind uwtable
+  define dso_local i32 @baa(i32 %arg1, i32 %arg2, i32 %arg3, i32 %arg4) local_unnamed_addr !dbg !9 {
+  entry:
+    %arg3.addr = alloca i32, align 4
+    %local2 = alloca i32, align 4
+    call void @llvm.dbg.value(metadata i32 %arg1, metadata !14, metadata !DIExpression()), !dbg !21
+    call void @llvm.dbg.value(metadata i32 %arg2, metadata !15, metadata !DIExpression()), !dbg !21
+    call void @llvm.dbg.value(metadata i32 %arg3, metadata !16, metadata !DIExpression()), !dbg !21
+    store i32 %arg3, i32* %arg3.addr, align 4
+    call void @llvm.dbg.value(metadata i32 %arg4, metadata !17, metadata !DIExpression()), !dbg !21
+    %0 = bitcast i32* %local2 to i8*, !dbg !21
+    call void @llvm.dbg.value(metadata i32* %arg3.addr, metadata !16, metadata !DIExpression(DW_OP_deref)), !dbg !21
+    %call = call i32 @foo(i32 %arg1, i32 %arg2, i32* nonnull %arg3.addr, i32 %arg4), !dbg !21
+    call void @llvm.dbg.value(metadata i32 %call, metadata !18, metadata !DIExpression()), !dbg !21
+    %cmp = icmp sgt i32 %arg1, %arg2, !dbg !21
+    %1 = load i32, i32* %arg3.addr, align 4, !dbg !21
+    call void @llvm.dbg.value(metadata i32 %1, metadata !16, metadata !DIExpression()), !dbg !21
+    %add = add nsw i32 %1, %arg1, !dbg !21
+    %add1 = add nsw i32 %arg4, %arg2, !dbg !21
+    %local1.0 = select i1 %cmp, i32 %add, i32 %add1, !dbg !21
+    call void @llvm.dbg.value(metadata i32 %local1.0, metadata !18, metadata !DIExpression()), !dbg !21
+    %rem = srem i32 %1, %arg1, !dbg !21
+    %tobool = icmp eq i32 %rem, 0, !dbg !21
+    %mul = mul nsw i32 %1, %arg1, !dbg !21
+    %add3 = add nsw i32 %1, %arg4, !dbg !21
+    %storemerge = select i1 %tobool, i32 %mul, i32 %add3, !dbg !21
+    call void @llvm.dbg.value(metadata i32 %storemerge, metadata !19, metadata !DIExpression()), !dbg !21
+    store i32 %storemerge, i32* %local2, align 4, !dbg !21
+    %cmp6 = icmp slt i32 %storemerge, %arg4, !dbg !21
+    %local3.0.v = select i1 %cmp6, i32 %local1.0, i32 %arg1, !dbg !21
+    %local3.0 = mul nsw i32 %local3.0.v, %storemerge, !dbg !21
+    call void @llvm.dbg.value(metadata i32 %local3.0, metadata !20, metadata !DIExpression()), !dbg !21
+    call void @llvm.dbg.value(metadata i32* %local2, metadata !19, metadata !DIExpression(DW_OP_deref)), !dbg !21
+    %call12 = call i32 @foo(i32 %local1.0, i32 4, i32* nonnull %local2, i32 %local3.0), !dbg !21
+    call void @llvm.dbg.value(metadata i32 %call12, metadata !14, metadata !DIExpression()), !dbg !21
+    %add13 = add nsw i32 %call12, 4, !dbg !21
+    ret i32 %add13, !dbg !21
+  }
+  
+  declare !dbg !4 dso_local i32 @foo(i32, i32, i32*, i32) local_unnamed_addr
+  
+  ; Function Attrs: nounwind readnone speculatable
+  declare void @llvm.dbg.value(metadata, metadata, metadata)
+  
+  !llvm.dbg.cu = !{!0}
+  !llvm.module.flags = !{!5, !6, !7}
+  !llvm.ident = !{!8}
+  
+  !0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 9.0.0", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, retainedTypes: !3, nameTableKind: None)
+  !1 = !DIFile(filename: "dbgcall-site-interpretation.c", directory: "/dir")
+  !2 = !{}
+  !3 = !{!4}
+  !4 = !DISubprogram(name: "foo", scope: !1, file: !1, line: 9, flags: DIFlagPrototyped, spFlags: DISPFlagOptimized, retainedNodes: !2)
+  !5 = !{i32 2, !"Dwarf Version", i32 4}
+  !6 = !{i32 2, !"Debug Info Version", i32 3}
+  !7 = !{i32 1, !"wchar_size", i32 4}
+  !8 = !{!"clang version 9.0.0"}
+  !9 = distinct !DISubprogram(name: "baa", scope: !1, file: !1, line: 10, type: !10, scopeLine: 10, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !13)
+  !10 = !DISubroutineType(types: !11)
+  !11 = !{!12, !12, !12, !12, !12}
+  !12 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+  !13 = !{!14, !15, !16, !17, !18, !19, !20}
+  !14 = !DILocalVariable(name: "arg1", arg: 1, scope: !9, file: !1, line: 10, type: !12)
+  !15 = !DILocalVariable(name: "arg2", arg: 2, scope: !9, file: !1, line: 10, type: !12, flags: DIFlagArgumentNotModified)
+  !16 = !DILocalVariable(name: "arg3", arg: 3, scope: !9, file: !1, line: 10, type: !12)
+  !17 = !DILocalVariable(name: "arg4", arg: 4, scope: !9, file: !1, line: 10, type: !12, flags: DIFlagArgumentNotModified)
+  !18 = !DILocalVariable(name: "local1", scope: !9, file: !1, line: 11, type: !12)
+  !19 = !DILocalVariable(name: "local2", scope: !9, file: !1, line: 11, type: !12)
+  !20 = !DILocalVariable(name: "local3", scope: !9, file: !1, line: 11, type: !12)
+  !21 = !DILocation(line: 10, column: 13, scope: !9)
+
+...
+---
+name:            baa
+liveins:         
+  - { reg: '$edi', virtual-reg: '' }
+  - { reg: '$esi', virtual-reg: '' }
+  - { reg: '$edx', virtual-reg: '' }
+  - { reg: '$ecx', virtual-reg: '' }
+callSites:       
+  - { bb: 0, offset: 23, fwdArgRegs: 
+      - { arg: 0, reg: '$edi' }
+      - { arg: 1, reg: '$esi' }
+      - { arg: 2, reg: '$rdx' }
+      - { arg: 3, reg: '$ecx' } }
+  - { bb: 0, offset: 49, fwdArgRegs: 
+      - { arg: 0, reg: '$edi' }
+      - { arg: 1, reg: '$esi' }
+      - { arg: 2, reg: '$rdx' }
+      - { arg: 3, reg: '$ecx' } }
+body:             |
+  bb.0.entry:
+    liveins: $ecx, $edi, $edx, $esi, $r15, $r14, $rbx
+  
+    DBG_VALUE $edi, $noreg, !14, !DIExpression(), debug-location !21
+    DBG_VALUE $esi, $noreg, !15, !DIExpression(), debug-location !21
+    DBG_VALUE $edx, $noreg, !16, !DIExpression(), debug-location !21
+    DBG_VALUE $ecx, $noreg, !17, !DIExpression(), debug-location !21
+    frame-setup PUSH64r killed $r15, implicit-def $rsp, implicit $rsp
+    CFI_INSTRUCTION def_cfa_offset 16
+    frame-setup PUSH64r killed $r14, implicit-def $rsp, implicit $rsp
+    CFI_INSTRUCTION def_cfa_offset 24
+    frame-setup PUSH64r killed $rbx, implicit-def $rsp, implicit $rsp
+    CFI_INSTRUCTION def_cfa_offset 32
+    $rsp = frame-setup SUB64ri8 $rsp, 16, implicit-def dead $eflags
+    CFI_INSTRUCTION def_cfa_offset 48
+    CFI_INSTRUCTION offset $rbx, -32
+    CFI_INSTRUCTION offset $r14, -24
+    CFI_INSTRUCTION offset $r15, -16
+    $r14d = MOV32rr $ecx, implicit-def $r14
+    DBG_VALUE $edx, $noreg, !16, !DIExpression(), debug-location !21
+    $r15d = MOV32rr $esi, implicit-def $r15
+    $ebx = MOV32rr $edi, implicit-def $rbx
+    $edi = MOV32rr $esi
+    MOV32mr $rsp, 1, $noreg, 8, $noreg, killed renamable $edx :: (store 4 into %ir.arg3.addr)
+    renamable $rdx = LEA64r $rsp, 1, $noreg, 8, $noreg
+    renamable $ecx = MOV32rr $r14d,
+    CALL64pcrel32 @foo, csr_64, implicit $rsp, implicit $ssp, implicit $edi, implicit $esi, implicit $rdx, implicit $ecx, implicit-def $rsp, implicit-def $ssp, implicit-def $eax, implicit-def $rax, debug-location !21
+    DBG_VALUE $noreg, $noreg, !18, !DIExpression(), debug-location !21
+    $rdx = MOV64rr renamable $rax
+    $ecx = KILL renamable $ecx, implicit-def $rcx 
+    renamable $eax = LEA64_32r renamable $rcx, 1, renamable $rbx, 0, $noreg, debug-location !21
+    renamable $edi = LEA64_32r renamable $r14, 1, renamable $r15, 0, $noreg, debug-location !21
+    CMP32rr renamable $ebx, renamable $r15d, implicit-def $eflags, implicit killed $r15, debug-location !21
+    renamable $edi = CMOV32rr killed renamable $edi, killed renamable $eax, 15, implicit killed $eflags, debug-location !21
+    DBG_VALUE $edi, $noreg, !18, !DIExpression(), debug-location !21
+    $eax = MOV32rr $ecx, debug-location !21
+    CDQ implicit-def $eax, implicit-def $edx, implicit $eax, debug-location !21
+    IDIV32r renamable $ebx, implicit-def dead $eax, implicit-def $edx, implicit-def dead $eflags, implicit $eax, implicit $edx, debug-location !21
+    $eax = MOV32rr $ecx, debug-location !21
+    renamable $eax = nsw IMUL32rr killed renamable $eax, renamable $ebx, implicit-def dead $eflags, debug-location !21
+    renamable $ecx = nsw ADD32rr renamable $ecx, renamable $r14d, implicit-def dead $eflags, implicit killed $rcx, implicit-def $rcx, debug-location !21
+    TEST32rr killed renamable $edx, renamable $edx, implicit-def $eflags, debug-location !21
+    renamable $ecx = CMOV32rr renamable $ecx, killed renamable $eax, 4, implicit killed $eflags, implicit killed $rcx, implicit-def $rcx, debug-location !21
+    DBG_VALUE $ecx, $noreg, !19, !DIExpression(), debug-location !21
+    MOV32mr $rsp, 1, $noreg, 12, $noreg, renamable $ecx, debug-location !21 :: (store 4 into %ir.local2)
+    CMP32rr renamable $ecx, renamable $r14d, implicit-def $eflags, implicit killed $r14, debug-location !21
+    renamable $ebx = CMOV32rr renamable $ebx, renamable $edi, 12, implicit killed $eflags, implicit killed $rbx, implicit-def $rbx, debug-location !21
+    renamable $ecx = nsw IMUL32rr renamable $ecx, renamable $ebx, implicit-def dead $eflags, implicit killed $rbx, implicit killed $rcx, implicit-def $rcx, debug-location !21
+    DBG_VALUE $rsp, $noreg, !19, !DIExpression(DW_OP_plus_uconst, 12, DW_OP_deref), debug-location !21
+    DBG_VALUE $ecx, $noreg, !20, !DIExpression(), debug-location !21
+    $esi = MOV32ri 4, debug-location !21
+    renamable $ecx = MOV32rm $rsp, 1, $noreg, 8, $noreg, implicit-def $rcx, debug-location !21 :: (dereferenceable load 4 from %ir.arg3.addr)
+    CALL64pcrel32 @foo, csr_64, implicit $rsp, implicit $ssp, implicit $edi, implicit $esi, implicit $rdx, implicit $ecx, implicit-def $rsp, implicit-def $ssp, implicit-def $eax, implicit-def $rax, debug-location !21
+    DBG_VALUE $eax, $noreg, !14, !DIExpression(), debug-location !21
+    renamable $eax = nsw ADD32ri8 killed renamable $eax, 4, implicit-def dead $eflags, debug-location !21
+    $rsp = frame-destroy ADD64ri8 $rsp, 16, implicit-def dead $eflags, debug-location !21
+    CFI_INSTRUCTION def_cfa_offset 32, debug-location !21
+    $rbx = frame-destroy POP64r implicit-def $rsp, implicit $rsp, debug-location !21
+    CFI_INSTRUCTION def_cfa_offset 24, debug-location !21
+    $r14 = frame-destroy POP64r implicit-def $rsp, implicit $rsp, debug-location !21
+    DBG_VALUE $ecx, $noreg, !17, !DIExpression(DW_OP_entry_value, 1), debug-location !21
+    CFI_INSTRUCTION def_cfa_offset 16, debug-location !21
+    $r15 = frame-destroy POP64r implicit-def $rsp, implicit $rsp, debug-location !21
+    DBG_VALUE $esi, $noreg, !15, !DIExpression(DW_OP_entry_value, 1), debug-location !21
+    CFI_INSTRUCTION def_cfa_offset 8, debug-location !21
+    RETQ $eax, debug-location !21
+
+...

llvm/test/DebugInfo/MIR/X86/dbgcall-site-lea-interpretation.mir

@@ -0,0 +1,140 @@
+# RUN: llc -debug-entry-values -start-after=machineverifier -filetype=obj %s -o -| llvm-dwarfdump -| FileCheck %s
+# CHECK:        DW_TAG_GNU_call_site
+# CHECK-NEXT:     DW_AT_abstract_origin {{.*}} "foo")
+# CHECK-NEXT:     DW_AT_low_pc {{.*}}
+# CHECK-EMPTY:
+# CHECK-NEXT:     DW_TAG_GNU_call_site_parameter
+# CHECK-NEXT:       DW_AT_location      (DW_OP_reg9 R9)
+# CHECK-NEXT:       DW_AT_GNU_call_site_value   (DW_OP_breg15 R15+10)
+# CHECK-EMPTY:
+# CHECK-NEXT:     DW_TAG_GNU_call_site_parameter
+# CHECK-NEXT:       DW_AT_location      (DW_OP_reg8 R8)
+# CHECK-NEXT:       DW_AT_GNU_call_site_value   (DW_OP_breg15 R15+0, DW_OP_lit2, DW_OP_mul, DW_OP_plus_uconst 0x8)
+# CHECK-EMPTY:
+# CHECK-NEXT:     DW_TAG_GNU_call_site_parameter
+# CHECK-NEXT:       DW_AT_location      (DW_OP_reg1 RDX)
+# CHECK-NEXT:       DW_AT_GNU_call_site_value   (DW_OP_breg14 R14+0, DW_OP_lit5, DW_OP_mul, DW_OP_plus_uconst 0x8)
+# CHECK-EMPTY:
+# CHECK-NEXT:     DW_TAG_GNU_call_site_parameter
+# CHECK-NEXT:       DW_AT_location      (DW_OP_reg4 RSI)
+# CHECK-NEXT:       DW_AT_GNU_call_site_value   (DW_OP_breg14 R14+0)
+# CHECK-EMPTY:
+# CHECK-NEXT:     DW_TAG_GNU_call_site_parameter
+# CHECK-NEXT:       DW_AT_location      (DW_OP_reg5 RDI)
+# CHECK-NEXT:       DW_AT_GNU_call_site_value   (DW_OP_breg14 R14+0, DW_OP_breg15 R15+0, DW_OP_lit2, DW_OP_mul, DW_OP_plus, DW_OP_plus_uconst 0x4)
+# CHECK-EMPTY:
+# CHECK-NEXT:     DW_TAG_GNU_call_site_parameter
+# CHECK-NEXT:       DW_AT_location      (DW_OP_reg2 RCX)
+# CHECK-NEXT:       DW_AT_GNU_call_site_value   (DW_OP_breg14 R14+0, DW_OP_breg15 R15+0, DW_OP_plus)
+# CHECK:        DW_TAG_GNU_call_site
+# CHECK-NEXT:     DW_AT_abstract_origin {{.*}} "foo2")
+# CHECK-NEXT:     DW_AT_low_pc {{.*}}
+# CHECK-EMPTY:
+# CHECK-NEXT:     DW_TAG_GNU_call_site_parameter
+# CHECK-NEXT:       DW_AT_location      (DW_OP_reg5 RDI)
+# CHECK-NEXT:       DW_AT_GNU_call_site_value   (DW_OP_breg14 R14+0, DW_OP_lit2, DW_OP_mul)
+--- |
+  ; ModuleID = 'dbgcall-site-lea-interpretation.ll'
+  source_filename = "dbgcall-site-lea-interpretation.c"
+  target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+  target triple = "x86_64-unknown-linux-gnu"
+  
+  define dso_local i32 @baa(i32 %arg1, i32 %arg2, i32 %arg3) local_unnamed_addr !dbg !10 {
+  entry:
+    %arg1.addr = alloca i32, align 4
+    %arg3.addr = alloca i32, align 4
+    %local1 = alloca i32, align 4
+    store i32 %arg1, i32* %arg1.addr, align 4
+    store i32 %arg3, i32* %arg3.addr, align 4
+    %0 = bitcast i32* %local1 to i8*, !dbg !14
+    %mul = mul nsw i32 %arg3, %arg1, !dbg !14
+    store i32 %mul, i32* %local1, align 4, !dbg !14
+    %add = add nsw i32 %arg2, %arg1, !dbg !14
+    %sub = sub nsw i32 %add, %arg3, !dbg !14
+    %call = call i32 @foo(i32 %mul, i32 %sub, i32* nonnull %local1, i32* nonnull %arg1.addr, i32* nonnull %arg3.addr, i32 %add), !dbg !14
+    %1 = load i32, i32* %local1, align 4, !dbg !14
+    %add2 = add nsw i32 %1, %call, !dbg !14
+    store i32 %add2, i32* %local1, align 4, !dbg !14
+    %call3 = call i32 @foo2(i32* nonnull %local1), !dbg !14
+    %2 = load i32, i32* %local1, align 4, !dbg !14
+    ret i32 %2, !dbg !14
+  }
+  
+  declare !dbg !4 dso_local i32 @foo(i32, i32, i32*, i32*, i32*, i32) local_unnamed_addr
+  
+  declare !dbg !5 dso_local i32 @foo2(i32*) local_unnamed_addr
+  
+  !llvm.dbg.cu = !{!0}
+  !llvm.module.flags = !{!6, !7, !8}
+  !llvm.ident = !{!9}
+  
+  !0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 9.0.0", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, retainedTypes: !3, nameTableKind: None)
+  !1 = !DIFile(filename: "dbgcall-site-lea-interpretation.c", directory: "/dir")
+  !2 = !{}
+  !3 = !{!4, !5}
+  !4 = !DISubprogram(name: "foo", scope: !1, file: !1, line: 8, flags: DIFlagPrototyped, spFlags: DISPFlagOptimized, retainedNodes: !2)
+  !5 = !DISubprogram(name: "foo2", scope: !1, file: !1, line: 9, flags: DIFlagPrototyped, spFlags: DISPFlagOptimized, retainedNodes: !2)
+  !6 = !{i32 2, !"Dwarf Version", i32 4}
+  !7 = !{i32 2, !"Debug Info Version", i32 3}
+  !8 = !{i32 1, !"wchar_size", i32 4}
+  !9 = !{!"clang version 9.0.0"}
+  !10 = distinct !DISubprogram(name: "baa", scope: !1, file: !1, line: 11, type: !11, scopeLine: 11, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !2)
+  !11 = !DISubroutineType(types: !12)
+  !12 = !{!13, !13, !13, !13}
+  !13 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+  !14 = !DILocation(line: 11, column: 13, scope: !10)
+
+...
+---
+name:            baa
+liveins:         
+  - { reg: '$edi', virtual-reg: '' }
+  - { reg: '$esi', virtual-reg: '' }
+  - { reg: '$edx', virtual-reg: '' }
+callSites:       
+  - { bb: 0, offset: 21, fwdArgRegs: 
+      - { arg: 0, reg: '$edi' }
+      - { arg: 1, reg: '$esi' }
+      - { arg: 2, reg: '$rdx' }
+      - { arg: 3, reg: '$rcx' }
+      - { arg: 4, reg: '$r8' }
+      - { arg: 5, reg: '$r9d' } }
+  - { bb: 0, offset: 24, fwdArgRegs: 
+      - { arg: 0, reg: '$rdi' } }
+body:             |
+  bb.0.entry:
+    liveins: $edi, $edx, $esi, $rbx
+  
+    frame-setup PUSH64r killed $rbx, implicit-def $rsp, implicit $rsp
+    CFI_INSTRUCTION def_cfa_offset 16
+    $rsp = frame-setup SUB64ri8 $rsp, 16, implicit-def dead $eflags
+    CFI_INSTRUCTION def_cfa_offset 32
+    CFI_INSTRUCTION offset $rbx, -16
+    $r9d = MOV32rr $esi
+    $r14 = MOV64rr $rsi
+    $r15 = MOV64rr $rdi
+    MOV32mr $rsp, 1, $noreg, 12, $noreg, renamable $edi :: (store 4 into %ir.arg1.addr)
+    MOV32mr $rsp, 1, $noreg, 8, $noreg, renamable $edx :: (store 4 into %ir.arg3.addr)
+    renamable $r9d = nsw ADD32rr killed renamable $r9d, renamable $edi, implicit-def dead $eflags, debug-location !14
+    $esi = MOV32rr $r9d, debug-location !14
+    renamable $esi = nsw SUB32rr killed renamable $esi, renamable $edx, implicit-def dead $eflags, debug-location !14
+    renamable $edx = nsw IMUL32rr killed renamable $edx, killed renamable $edi, implicit-def dead $eflags, debug-location !14
+    MOV32mr $rsp, 1, $noreg, 4, $noreg, renamable $edx, debug-location !14 :: (store 4 into %ir.local1)
+    renamable $rcx = LEA64r $r14, 1, $r15, 0, $noreg
+    renamable $rdi = LEA64r $r14, 2, $r15, 4, $noreg
+    renamable $rsi = LEA64r $r14, 1, $noreg, 0, $noreg
+    renamable $rdx = LEA64r $r14, 4, $r14, 8, $noreg
+    renamable $r8 = LEA64r $noreg, 2, $r15, 8, $noreg
+    renamable $r9 = LEA64r  $noreg, 1, $r15, 10, $noreg, implicit-def $r9d
+    CALL64pcrel32 @foo, csr_64, implicit $rsp, implicit $ssp, implicit $edi, implicit $esi, implicit $rdx, implicit $rcx, implicit $r8, implicit $r9d, implicit-def $rsp, implicit-def $ssp, implicit-def $eax, debug-location !14
+    ADD32mr $rsp, 1, $noreg, 4, $noreg, killed renamable $eax, implicit-def dead $eflags, debug-location !14 :: (store 4 into %ir.local1), (dereferenceable load 4 from %ir.local1)
+    $rdi = LEA64r $r14, 1, killed $r14, 0, $noreg
+    CALL64pcrel32 @foo2, csr_64, implicit $rsp, implicit $ssp, implicit $rdi, implicit-def $rsp, implicit-def $ssp, implicit-def dead $eax, debug-location !14
+    renamable $eax = MOV32rm $rsp, 1, $noreg, 4, $noreg, debug-location !14 :: (dereferenceable load 4 from %ir.local1)
+    $rsp = frame-destroy ADD64ri8 $rsp, 16, implicit-def dead $eflags, debug-location !14
+    CFI_INSTRUCTION def_cfa_offset 16, debug-location !14
+    $rbx = frame-destroy POP64r implicit-def $rsp, implicit $rsp, debug-location !14
+    CFI_INSTRUCTION def_cfa_offset 8, debug-location !14
+    RETQ $eax, debug-location !14
+
+...

llvm/test/DebugInfo/MIR/X86/debug-call-site-param.mir

@@ -0,0 +1,159 @@
+# RUN: llc -debug-entry-values -filetype=obj -mtriple=x86_64-unknown-unknown -start-after=machineverifier -o - %s| llvm-dwarfdump - | FileCheck %s
+#
+# extern void foo(int *a, int b, int c, int d, int e, int f);
+# extern int getVal();
+#
+# void baa(int arg1, int arg2, int arg3) {
+#   int local1 = getVal();
+#   foo(&local1, arg2, 10, 15, arg3 + 3, arg1 + arg2);
+# }
+#
+# CHECK: DW_TAG_GNU_call_site
+# CHECK:   DW_AT_abstract_origin {{.*}} "getVal"
+#
+# CHECK:       DW_TAG_GNU_call_site
+# CHECK:         DW_AT_abstract_origin {{.*}} "foo"
+# CHECK:         DW_AT_low_pc {{.*}}
+# CHECK-EMPTY:
+# CHECK:         DW_TAG_GNU_call_site_parameter
+# CHECK-NEXT:      DW_AT_location      (DW_OP_reg2 RCX)
+# CHECK-NEXT:      DW_AT_GNU_call_site_value   (DW_OP_lit15)
+# CHECK:         DW_TAG_GNU_call_site_parameter
+# CHECK-NEXT:      DW_AT_location      (DW_OP_reg1 RDX)
+# CHECK-NEXT:      DW_AT_GNU_call_site_value   (DW_OP_lit10)
+# CHECK:         DW_TAG_GNU_call_site_parameter
+# CHECK-NEXT:      DW_AT_location      (DW_OP_reg4 RSI)
+# CHECK-NEXT:      DW_AT_GNU_call_site_value   (DW_OP_breg3 RBX+0)
+# CHECK:         DW_TAG_GNU_call_site_parameter
+# CHECK-NEXT:      DW_AT_location      (DW_OP_reg5 RDI)
+# CHECK-NEXT:      DW_AT_GNU_call_site_value   (DW_OP_fbreg +12)
+# CHECK:         DW_TAG_GNU_call_site_parameter
+# CHECK-NEXT:      DW_AT_location      (DW_OP_reg9 R9)
+# CHECK-NEXT:      DW_AT_GNU_call_site_value   (DW_OP_breg15 R15+0, DW_OP_breg3 RBX+0, DW_OP_plus)
+# CHECK:         DW_TAG_GNU_call_site_parameter
+# CHECK-NEXT:      DW_AT_location      (DW_OP_reg8 R8)
+# CHECK-NEXT:      DW_AT_GNU_call_site_value   (DW_OP_breg14 R14+3)
+--- |
+  ; ModuleID = 'test.c'
+  source_filename = "test.c"
+  target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+  target triple = "x86_64-unknown-linux-gnu"
+  
+  ; Function Attrs: nounwind uwtable
+  define dso_local void @baa(i32 %arg1, i32 %arg2, i32 %arg3) local_unnamed_addr !dbg !10 {
+  entry:
+    %local1 = alloca i32, align 4
+    call void @llvm.dbg.value(metadata i32 %arg1, metadata !15, metadata !DIExpression()), !dbg !19
+    call void @llvm.dbg.value(metadata i32 %arg2, metadata !16, metadata !DIExpression()), !dbg !20
+    call void @llvm.dbg.value(metadata i32 %arg3, metadata !17, metadata !DIExpression()), !dbg !21
+    %0 = bitcast i32* %local1 to i8*, !dbg !22
+    %call = tail call i32 (...) @getVal(), !dbg !23
+    call void @llvm.dbg.value(metadata i32 %call, metadata !18, metadata !DIExpression()), !dbg !24
+    store i32 %call, i32* %local1, align 4, !dbg !24
+    %add = add nsw i32 %arg3, 3, !dbg !24
+    %add1 = add nsw i32 %arg2, %arg1, !dbg !24
+    call void @llvm.dbg.value(metadata i32* %local1, metadata !18, metadata !DIExpression(DW_OP_deref)), !dbg !24
+    call void @foo(i32* nonnull %local1, i32 %arg2, i32 10, i32 15, i32 %add, i32 %add1), !dbg !24
+    ret void, !dbg !24
+  }
+  
+  declare !dbg !4 dso_local i32 @getVal(...) local_unnamed_addr
+  
+  declare !dbg !5 dso_local void @foo(i32*, i32, i32, i32, i32, i32) local_unnamed_addr
+  
+  ; Function Attrs: nounwind readnone speculatable
+  declare void @llvm.dbg.value(metadata, metadata, metadata)
+  
+  !llvm.dbg.cu = !{!0}
+  !llvm.module.flags = !{!6, !7, !8}
+  !llvm.ident = !{!9}
+  
+  !0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 9.0.0", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, retainedTypes: !3, nameTableKind: None)
+  !1 = !DIFile(filename: "test.c", directory: "/dir")
+  !2 = !{}
+  !3 = !{!4, !5}
+  !4 = !DISubprogram(name: "getVal", scope: !1, file: !1, line: 2, spFlags: DISPFlagOptimized, retainedNodes: !2)
+  !5 = !DISubprogram(name: "foo", scope: !1, file: !1, line: 1, flags: DIFlagPrototyped, spFlags: DISPFlagOptimized, retainedNodes: !2)
+  !6 = !{i32 2, !"Dwarf Version", i32 4}
+  !7 = !{i32 2, !"Debug Info Version", i32 3}
+  !8 = !{i32 1, !"wchar_size", i32 4}
+  !9 = !{!"clang version 9.0.0"}
+  !10 = distinct !DISubprogram(name: "baa", scope: !1, file: !1, line: 4, type: !11, scopeLine: 4, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !14)
+  !11 = !DISubroutineType(types: !12)
+  !12 = !{null, !13, !13, !13}
+  !13 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+  !14 = !{!15, !16, !17, !18}
+  !15 = !DILocalVariable(name: "arg1", arg: 1, scope: !10, file: !1, line: 4, type: !13, flags: DIFlagArgumentNotModified)
+  !16 = !DILocalVariable(name: "arg2", arg: 2, scope: !10, file: !1, line: 4, type: !13, flags: DIFlagArgumentNotModified)
+  !17 = !DILocalVariable(name: "arg3", arg: 3, scope: !10, file: !1, line: 4, type: !13, flags: DIFlagArgumentNotModified)
+  !18 = !DILocalVariable(name: "local1", scope: !10, file: !1, line: 5, type: !13)
+  !19 = !DILocation(line: 4, column: 14, scope: !10)
+  !20 = !DILocation(line: 4, column: 24, scope: !10)
+  !21 = !DILocation(line: 4, column: 34, scope: !10)
+  !22 = !DILocation(line: 5, column: 3, scope: !10)
+  !23 = !DILocation(line: 5, column: 16, scope: !10)
+  !24 = !DILocation(line: 5, column: 7, scope: !10)
+
+...
+---
+name:            baa
+liveins:         
+  - { reg: '$edi', virtual-reg: '' }
+  - { reg: '$esi', virtual-reg: '' }
+  - { reg: '$edx', virtual-reg: '' }
+callSites:       
+  - { bb: 0, offset: 21, fwdArgRegs: [] }
+  - { bb: 0, offset: 31, fwdArgRegs: 
+      - { arg: 0, reg: '$rdi' }
+      - { arg: 1, reg: '$esi' }
+      - { arg: 2, reg: '$edx' }
+      - { arg: 3, reg: '$ecx' }
+      - { arg: 4, reg: '$r8d' }
+      - { arg: 5, reg: '$r9d' } }
+body:             |
+  bb.0.entry:
+    liveins: $edi, $edx, $esi, $r15, $r14, $rbx
+  
+    DBG_VALUE $edi, $noreg, !15, !DIExpression(), debug-location !19
+    DBG_VALUE $esi, $noreg, !16, !DIExpression(), debug-location !20
+    DBG_VALUE $edx, $noreg, !17, !DIExpression(), debug-location !21
+    frame-setup PUSH64r killed $r15, implicit-def $rsp, implicit $rsp
+    CFI_INSTRUCTION def_cfa_offset 16
+    frame-setup PUSH64r killed $r14, implicit-def $rsp, implicit $rsp
+    CFI_INSTRUCTION def_cfa_offset 24
+    frame-setup PUSH64r killed $rbx, implicit-def $rsp, implicit $rsp
+    CFI_INSTRUCTION def_cfa_offset 32
+    $rsp = frame-setup SUB64ri8 $rsp, 16, implicit-def dead $eflags
+    CFI_INSTRUCTION def_cfa_offset 48
+    CFI_INSTRUCTION offset $rbx, -32
+    CFI_INSTRUCTION offset $r14, -24
+    CFI_INSTRUCTION offset $r15, -16
+    $r14d = MOV32rr $edx, implicit-def $r14
+    $ebx = MOV32rr $esi, implicit-def $rbx
+    $r15d = MOV32rr $edi, implicit-def $r15
+    DBG_VALUE $r14d, $noreg, !17, !DIExpression(), debug-location !21
+    DBG_VALUE $ebx, $noreg, !16, !DIExpression(), debug-location !20
+    DBG_VALUE $r15d, $noreg, !15, !DIExpression(), debug-location !19
+    dead $eax = XOR32rr undef $eax, undef $eax, implicit-def dead $eflags, implicit-def $al, debug-location !23
+    CALL64pcrel32 @getVal, csr_64, implicit $rsp, implicit $ssp, implicit $al, implicit-def $rsp, implicit-def $ssp, implicit-def $eax, debug-location !23
+    DBG_VALUE $eax, $noreg, !18, !DIExpression(), debug-location !24
+    MOV32mr $rsp, 1, $noreg, 12, $noreg, killed renamable $eax, debug-location !24 :: (store 4 into %ir.local1)
+    renamable $r8d = LEA64_32r killed renamable $r14, 1, $noreg, 3, $noreg, debug-location !24
+    renamable $r9d = LEA64_32r killed renamable $r15, 1, renamable $rbx, 0, $noreg, debug-location !24
+    DBG_VALUE $rsp, $noreg, !18, !DIExpression(DW_OP_plus_uconst, 12, DW_OP_deref), debug-location !24
+    renamable $rdi = LEA64r $rsp, 1, $noreg, 12, $noreg
+    $esi = MOV32rr $ebx, implicit killed $rbx, debug-location !24
+    $edx = MOV32ri 10, debug-location !24
+    $ecx = MOV32ri 15, debug-location !24
+    CALL64pcrel32 @foo, csr_64, implicit $rsp, implicit $ssp, implicit $rdi, implicit $esi, implicit $edx, implicit killed $ecx, implicit $r8d, implicit $r9d, implicit-def $rsp, implicit-def $ssp, debug-location !24
+    $rsp = frame-destroy ADD64ri8 $rsp, 16, implicit-def dead $eflags, debug-location !24
+    CFI_INSTRUCTION def_cfa_offset 32, debug-location !24
+    $rbx = frame-destroy POP64r implicit-def $rsp, implicit $rsp, debug-location !24
+    CFI_INSTRUCTION def_cfa_offset 24, debug-location !24
+    $r14 = frame-destroy POP64r implicit-def $rsp, implicit $rsp, debug-location !24
+    CFI_INSTRUCTION def_cfa_offset 16, debug-location !24
+    $r15 = frame-destroy POP64r implicit-def $rsp, implicit $rsp, debug-location !24
+    CFI_INSTRUCTION def_cfa_offset 8, debug-location !24
+    RETQ debug-location !24
+
+...

llvm/test/DebugInfo/X86/dwarf-callsite-related-attrs.ll

@@ -14,14 +14,14 @@
 
 ; REQUIRES: object-emission
 ; RUN: %llc_dwarf -mtriple=x86_64-- < %s -o - | FileCheck %s -check-prefix=ASM
-; RUN: %llc_dwarf -mtriple=x86_64-- < %s -filetype=obj -o %t.o
+; RUN: %llc_dwarf -debugger-tune=lldb -mtriple=x86_64-- < %s -filetype=obj -o %t.o
 ; RUN: llvm-dwarfdump %t.o -o - | FileCheck %s -check-prefix=OBJ -implicit-check-not=DW_TAG_call_site
 ; RUN: llvm-dwarfdump -verify %t.o 2>&1 | FileCheck %s -check-prefix=VERIFY
 ; RUN: llvm-dwarfdump -statistics %t.o | FileCheck %s -check-prefix=STATS
 ; RUN: llvm-as < %s | llvm-dis | llvm-as | llvm-dis -o /dev/null
 
 ; VERIFY: No errors.
-; STATS: "call site entries":5
+; STATS: "call site DIEs":6
 
 @sink = global i32 0, align 4, !dbg !0
 
@@ -85,6 +85,9 @@ entry:
 ; OBJ:   DW_TAG_call_site
 ; OBJ:     DW_AT_call_origin ([[foo_sp]])
 ; OBJ:     DW_AT_call_return_pc
+; OBJ:   DW_TAG_call_site
+; OBJ:     DW_AT_call_target
+; OBJ:     DW_AT_call_return_pc
 define i32 @main() !dbg !29 {
 entry:
   call void @_Z3foov(), !dbg !32

llvm/test/tools/llvm-dwarfdump/X86/stats-dbg-callsite-info.ll

@@ -0,0 +1,76 @@
+; RUN: llc -debug-entry-values %s -o - -filetype=obj \
+; RUN:   | llvm-dwarfdump -statistics - | FileCheck %s
+;
+; The LLVM IR file was generated on this source code by using
+; option '-femit-param-entry-values'.
+;
+; extern void foo(int *a, int b, int c, int d, int e, int f);
+; extern int getVal();
+;
+; void baa(int arg1, int arg2, int arg3) {
+;   int local1 = getVal();
+;   foo(&local1, arg2, 10, 15, arg3 + 3, arg1 + arg2);
+; }
+;
+; CHECK: "call site DIEs":2
+; CHECK-SAME: "call site parameter DIEs":6
+;
+; ModuleID = 'test.c'
+source_filename = "test.c"
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; Function Attrs: nounwind uwtable
+define dso_local void @baa(i32 %arg1, i32 %arg2, i32 %arg3) local_unnamed_addr #0 !dbg !10 {
+entry:
+  %local1 = alloca i32, align 4
+  call void @llvm.dbg.value(metadata i32 %arg1, metadata !15, metadata !DIExpression()), !dbg !19
+  call void @llvm.dbg.value(metadata i32 %arg2, metadata !16, metadata !DIExpression()), !dbg !20
+  call void @llvm.dbg.value(metadata i32 %arg3, metadata !17, metadata !DIExpression()), !dbg !21
+  %0 = bitcast i32* %local1 to i8*, !dbg !22
+  %call = tail call i32 (...) @getVal(), !dbg !23
+  call void @llvm.dbg.value(metadata i32 %call, metadata !18, metadata !DIExpression()), !dbg !24
+  store i32 %call, i32* %local1, align 4, !dbg !24
+  %add = add nsw i32 %arg3, 3, !dbg !24
+  %add1 = add nsw i32 %arg2, %arg1, !dbg !24
+  call void @llvm.dbg.value(metadata i32* %local1, metadata !18, metadata !DIExpression(DW_OP_deref)), !dbg !24
+  call void @foo(i32* nonnull %local1, i32 %arg2, i32 10, i32 15, i32 %add, i32 %add1), !dbg !24
+  ret void, !dbg !24
+}
+
+declare !dbg !4 dso_local i32 @getVal(...) local_unnamed_addr
+
+declare !dbg !5 dso_local void @foo(i32*, i32, i32, i32, i32, i32) local_unnamed_addr
+
+; Function Attrs: nounwind readnone speculatable
+declare void @llvm.dbg.value(metadata, metadata, metadata)
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!6, !7, !8}
+!llvm.ident = !{!9}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 9.0.0", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, retainedTypes: !3, nameTableKind: None)
+!1 = !DIFile(filename: "test.c", directory: "/dir")
+!2 = !{}
+!3 = !{!4, !5}
+!4 = !DISubprogram(name: "getVal", scope: !1, file: !1, line: 2, spFlags: DISPFlagOptimized, retainedNodes: !2)
+!5 = !DISubprogram(name: "foo", scope: !1, file: !1, line: 1, flags: DIFlagPrototyped, spFlags: DISPFlagOptimized, retainedNodes: !2)
+!6 = !{i32 2, !"Dwarf Version", i32 4}
+!7 = !{i32 2, !"Debug Info Version", i32 3}
+!8 = !{i32 1, !"wchar_size", i32 4}
+!9 = !{!"clang version 9.0.0"}
+!10 = distinct !DISubprogram(name: "baa", scope: !1, file: !1, line: 4, type: !11, scopeLine: 4, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !14)
+!11 = !DISubroutineType(types: !12)
+!12 = !{null, !13, !13, !13}
+!13 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!14 = !{!15, !16, !17, !18}
+!15 = !DILocalVariable(name: "arg1", arg: 1, scope: !10, file: !1, line: 4, type: !13, flags: DIFlagArgumentNotModified)
+!16 = !DILocalVariable(name: "arg2", arg: 2, scope: !10, file: !1, line: 4, type: !13, flags: DIFlagArgumentNotModified)
+!17 = !DILocalVariable(name: "arg3", arg: 3, scope: !10, file: !1, line: 4, type: !13, flags: DIFlagArgumentNotModified)
+!18 = !DILocalVariable(name: "local1", scope: !10, file: !1, line: 5, type: !13)
+!19 = !DILocation(line: 4, column: 14, scope: !10)
+!20 = !DILocation(line: 4, column: 24, scope: !10)
+!21 = !DILocation(line: 4, column: 34, scope: !10)
+!22 = !DILocation(line: 5, column: 3, scope: !10)
+!23 = !DILocation(line: 5, column: 16, scope: !10)
+!24 = !DILocation(line: 5, column: 7, scope: !10)

llvm/tools/llvm-dwarfdump/Statistics.cpp

@@ -56,9 +56,12 @@ struct GlobalStats {
   /// Total number of PC range bytes in each variable's enclosing scope,
   /// starting from the first definition of the variable.
   unsigned ScopeBytesFromFirstDefinition = 0;
-  /// Total number of call site entries (DW_TAG_call_site) or
+  /// Total number of call site entries (DW_AT_call_file & DW_AT_call_line).
-  /// (DW_AT_call_file & DW_AT_call_line).
   unsigned CallSiteEntries = 0;
+  /// Total number of call site DIEs (DW_TAG_call_site).
+  unsigned CallSiteDIEs = 0;
+  /// Total number of call site parameter DIEs (DW_TAG_call_site_parameter).
+  unsigned CallSiteParamDIEs = 0;
   /// Total byte size of concrete functions. This byte size includes
   /// inline functions contained in the concrete functions.
   uint64_t FunctionSize = 0;
@@ -94,8 +97,15 @@ static void collectStatsForDie(DWARFDie Die, std::string FnPrefix,
   uint64_t BytesCovered = 0;
   uint64_t OffsetToFirstDefinition = 0;
 
-  if (Die.getTag() == dwarf::DW_TAG_call_site) {
+  if (Die.getTag() == dwarf::DW_TAG_call_site ||
-    GlobalStats.CallSiteEntries++;
+      Die.getTag() == dwarf::DW_TAG_GNU_call_site) {
+    GlobalStats.CallSiteDIEs++;
+    return;
+  }
+
+  if (Die.getTag() == dwarf::DW_TAG_call_site_parameter ||
+      Die.getTag() == dwarf::DW_TAG_GNU_call_site_parameter) {
+    GlobalStats.CallSiteParamDIEs++;
     return;
   }
 
@@ -387,6 +397,8 @@ bool collectStatsForObjectFile(ObjectFile &Obj, DWARFContext &DICtx,
   printDatum(OS, "source variables", VarParamTotal);
   printDatum(OS, "variables with location", VarParamWithLoc);
   printDatum(OS, "call site entries", GlobalStats.CallSiteEntries);
+  printDatum(OS, "call site DIEs", GlobalStats.CallSiteDIEs);
+  printDatum(OS, "call site parameter DIEs", GlobalStats.CallSiteParamDIEs);
   printDatum(OS, "scope bytes total",
              GlobalStats.ScopeBytesFromFirstDefinition);
   printDatum(OS, "scope bytes covered", GlobalStats.ScopeBytesCovered);