Update aosp/master LLVM for rebase to r222494.

Change-Id: Ic787f5e0124df789bd26f3f24680f45e678eef2d

1 files changed, 59 insertions, 38 deletions

diff --git a/lib/CodeGen/AsmPrinter/DbgValueHistoryCalculator.cpp b/lib/CodeGen/AsmPrinter/DbgValueHistoryCalculator.cpp
index a66d08e..0c2a5e5 100644
--- a/lib/CodeGen/AsmPrinter/DbgValueHistoryCalculator.cpp
+++ b/lib/CodeGen/AsmPrinter/DbgValueHistoryCalculator.cpp
@@ -8,25 +8,25 @@
 //===----------------------------------------------------------------------===//
 
 #include "DbgValueHistoryCalculator.h"
+#include "llvm/ADT/BitVector.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/CodeGen/MachineBasicBlock.h"
 #include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/IR/DebugInfo.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Target/TargetRegisterInfo.h"
 #include <algorithm>
 #include <map>
-#include <set>
+using namespace llvm;
 
 #define DEBUG_TYPE "dwarfdebug"
 
-namespace llvm {
-
 // \brief If @MI is a DBG_VALUE with debug value described by a
 // defined register, returns the number of this register.
 // 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;
@@ -36,7 +36,7 @@ void DbgValueHistoryMap::startInstrRange(const MDNode *Var,
                                          const MachineInstr &MI) {
   // Instruction range should start with a DBG_VALUE instruction for the
   // variable.
-  assert(MI.isDebugValue() && 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)) {
@@ -96,6 +96,19 @@ static void addRegDescribedVar(RegDescribedVarsMap &RegVars,
   VarSet.push_back(Var);
 }
 
+// \brief Terminate the location range for variables described by register at
+// @I by inserting @ClobberingInstr to their history.
+static void clobberRegisterUses(RegDescribedVarsMap &RegVars,
+                                RegDescribedVarsMap::iterator I,
+                                DbgValueHistoryMap &HistMap,
+                                const MachineInstr &ClobberingInstr) {
+  // Iterate over all variables described by this register and add this
+  // instruction to their history, clobbering it.
+  for (const auto &Var : I->second)
+    HistMap.endInstrRange(Var, ClobberingInstr);
+  RegVars.erase(I);
+}
+
 // \brief Terminate the location range for variables described by register
 // @RegNo by inserting @ClobberingInstr to their history.
 static void clobberRegisterUses(RegDescribedVarsMap &RegVars, unsigned RegNo,
@@ -104,22 +117,26 @@ static void clobberRegisterUses(RegDescribedVarsMap &RegVars, unsigned RegNo,
   const auto &I = RegVars.find(RegNo);
   if (I == RegVars.end())
     return;
-  // Iterate over all variables described by this register and add this
-  // instruction to their history, clobbering it.
-  for (const auto &Var : I->second)
-    HistMap.endInstrRange(Var, ClobberingInstr);
-  RegVars.erase(I);
+  clobberRegisterUses(RegVars, I, HistMap, ClobberingInstr);
 }
 
-// \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);
   }
 }
 
@@ -133,11 +150,12 @@ static const MachineInstr *getFirstEpilogueInst(const MachineBasicBlock &MBB) {
   // as the return instruction.
   DebugLoc LastLoc = LastMI->getDebugLoc();
   auto Res = LastMI;
-  for (MachineBasicBlock::const_reverse_iterator I(std::next(LastMI)); I != MBB.rend();
-       ++I) {
+  for (MachineBasicBlock::const_reverse_iterator I(std::next(LastMI)),
+       E = MBB.rend();
+       I != E; ++I) {
     if (I->getDebugLoc() != LastLoc)
       return Res;
-    Res = std::prev(I.base());
+    Res = &*I;
   }
   // If all instructions have the same debug location, assume whole MBB is
   // an epilogue.
@@ -145,25 +163,26 @@ 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) {
+                                BitVector &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.set(r); });
     }
   }
 }
 
-void calculateDbgValueHistory(const MachineFunction *MF,
-                              const TargetRegisterInfo *TRI,
-                              DbgValueHistoryMap &Result) {
-  std::set<unsigned> ChangingRegs;
+void llvm::calculateDbgValueHistory(const MachineFunction *MF,
+                                    const TargetRegisterInfo *TRI,
+                                    DbgValueHistoryMap &Result) {
+  BitVector ChangingRegs(TRI->getNumRegs());
   collectChangingRegs(MF, TRI, ChangingRegs);
 
   RegDescribedVarsMap RegVars;
@@ -172,17 +191,18 @@ 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) {
-          if (ChangingRegs.count(RegNo))
+        applyToClobberedRegisters(MI, TRI, [&](unsigned RegNo) {
+          if (ChangingRegs.test(RegNo))
             clobberRegisterUses(RegVars, RegNo, Result, MI);
-        }
+        });
         continue;
       }
 
       assert(MI.getNumOperands() > 1 && "Invalid DBG_VALUE instruction!");
-      const MDNode *Var = MI.getDebugVariable();
+      // 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 = MI.getDebugVariable();
 
       if (unsigned PrevReg = Result.getRegisterForVar(Var))
         dropRegDescribedVar(RegVars, PrevReg, Var);
@@ -196,11 +216,12 @@ void calculateDbgValueHistory(const MachineFunction *MF,
     // Make sure locations for register-described variables are valid only
     // until the end of the basic block (unless it's the last basic block, in
     // which case let their liveness run off to the end of the function).
-    if (!MBB.empty() &&  &MBB != &MF->back()) {
-      for (unsigned RegNo : ChangingRegs)
-        clobberRegisterUses(RegVars, RegNo, Result, MBB.back());
+    if (!MBB.empty() && &MBB != &MF->back()) {
+      for (auto I = RegVars.begin(), E = RegVars.end(); I != E;) {
+        auto CurElem = I++; // CurElem can be erased below.
+        if (ChangingRegs.test(CurElem->first))
+          clobberRegisterUses(RegVars, CurElem, Result, MBB.back());
+      }
     }
   }
 }
-
-}