Move the complex address expression out of DIVariable and into an extra

[oota-llvm.git] / lib / CodeGen / AsmPrinter / DbgValueHistoryCalculator.cpp

diff --git a/lib/CodeGen/AsmPrinter/DbgValueHistoryCalculator.cpp b/lib/CodeGen/AsmPrinter/DbgValueHistoryCalculator.cpp
index f557ccddb47dce36380f60cffc7e83fca9c8cf93..a258d621a6a01470633d2ee77615f5a26f62fec8 100644 (file)
--- a/lib/CodeGen/AsmPrinter/DbgValueHistoryCalculator.cpp
+++ b/lib/CodeGen/AsmPrinter/DbgValueHistoryCalculator.cpp
@@ -27,7 +27,7 @@ namespace llvm {
 // In the other case, returns 0.
 static unsigned isDescribedByReg(const MachineInstr &MI) {
   assert(MI.isDebugValue());
-  assert(MI.getNumOperands() == 3);
+  assert(MI.getNumOperands() == 4);
   // If location of variable is described using a register (directly or
   // indirecltly), this register is always a first operand.
   return MI.getOperand(0).isReg() ? MI.getOperand(0).getReg() : 0;
@@ -37,7 +37,7 @@ void DbgValueHistoryMap::startInstrRange(const MDNode *Var,
                                          const MachineInstr &MI) {
   // Instruction range should start with a DBG_VALUE instruction for the
   // variable.
-  assert(MI.isDebugValue() && getEntireVariable(MI.getDebugVariable()) == Var);
+  assert(MI.isDebugValue() && "not a DBG_VALUE");
   auto &Ranges = VarInstrRanges[Var];
   if (!Ranges.empty() && Ranges.back().second == nullptr &&
       Ranges.back().first->isIdenticalTo(&MI)) {
@@ -112,15 +112,23 @@ static void clobberRegisterUses(RegDescribedVarsMap &RegVars, unsigned RegNo,
   RegVars.erase(I);
 }
 
-// \brief Collect all registers clobbered by @MI and insert them to @Regs.
-static void collectClobberedRegisters(const MachineInstr &MI,
+// \brief Collect all registers clobbered by @MI and apply the functor
+// @Func to their RegNo.
+// @Func should be a functor with a void(unsigned) signature. We're
+// not using std::function here for performance reasons. It has a
+// small but measurable impact. By using a functor instead of a
+// std::set& here, we can avoid the overhead of constructing
+// temporaries in calculateDbgValueHistory, which has a significant
+// performance impact.
+template<typename Callable>
+static void applyToClobberedRegisters(const MachineInstr &MI,
                                       const TargetRegisterInfo *TRI,
-                                      std::set<unsigned> &Regs) {
+                                      Callable Func) {
   for (const MachineOperand &MO : MI.operands()) {
     if (!MO.isReg() || !MO.isDef() || !MO.getReg())
       continue;
     for (MCRegAliasIterator AI(MO.getReg(), TRI, true); AI.isValid(); ++AI)
-      Regs.insert(*AI);
+      Func(*AI);
   }
 }
 
@@ -146,17 +154,18 @@ static const MachineInstr *getFirstEpilogueInst(const MachineBasicBlock &MBB) {
 }
 
 // \brief Collect registers that are modified in the function body (their
-// contents is changed only in the prologue and epilogue).
+// contents is changed outside of the prologue and epilogue).
 static void collectChangingRegs(const MachineFunction *MF,
                                 const TargetRegisterInfo *TRI,
                                 std::set<unsigned> &Regs) {
   for (const auto &MBB : *MF) {
     auto FirstEpilogueInst = getFirstEpilogueInst(MBB);
-    bool IsInEpilogue = false;
+
     for (const auto &MI : MBB) {
-      IsInEpilogue |= &MI == FirstEpilogueInst;
-      if (!MI.getFlag(MachineInstr::FrameSetup) && !IsInEpilogue)
-        collectClobberedRegisters(MI, TRI, Regs);
+      if (&MI == FirstEpilogueInst)
+        break;
+      if (!MI.getFlag(MachineInstr::FrameSetup))
+        applyToClobberedRegisters(MI, TRI, [&](unsigned r) { Regs.insert(r); });
     }
   }
 }
@@ -173,12 +182,10 @@ void calculateDbgValueHistory(const MachineFunction *MF,
       if (!MI.isDebugValue()) {
         // Not a DBG_VALUE instruction. It may clobber registers which describe
         // some variables.
-        std::set<unsigned> MIClobberedRegs;
-        collectClobberedRegisters(MI, TRI, MIClobberedRegs);
-        for (unsigned RegNo : MIClobberedRegs) {
+        applyToClobberedRegisters(MI, TRI, [&](unsigned RegNo) {
           if (ChangingRegs.count(RegNo))
             clobberRegisterUses(RegVars, RegNo, Result, MI);
-        }
+        });
         continue;
       }
 
@@ -186,7 +193,7 @@ void calculateDbgValueHistory(const MachineFunction *MF,
       // Use the base variable (without any DW_OP_piece expressions)
       // as index into History. The full variables including the
       // piece expressions are attached to the MI.
-      DIVariable Var = getEntireVariable(MI.getDebugVariable());
+      DIVariable Var = MI.getDebugVariable();
 
       if (unsigned PrevReg = Result.getRegisterForVar(Var))
         dropRegDescribedVar(RegVars, PrevReg, Var);