Sink DwarfDebug::attachLowHighPC into DwarfCompileUnit

[oota-llvm.git] / lib / CodeGen / VirtRegMap.cpp

diff --git a/lib/CodeGen/VirtRegMap.cpp b/lib/CodeGen/VirtRegMap.cpp
index 47772e7c02f1002f1b973cb007bc201edc1b038c..7b41e21d7017ad739f0c4893d80e4a1e8debaf47 100644 (file)
--- a/lib/CodeGen/VirtRegMap.cpp
+++ b/lib/CodeGen/VirtRegMap.cpp
@@ -16,12 +16,11 @@
 //
 //===----------------------------------------------------------------------===//
 
-#define DEBUG_TYPE "regalloc"
 #include "llvm/CodeGen/VirtRegMap.h"
 #include "LiveDebugVariables.h"
 #include "llvm/ADT/STLExtras.h"
-#include "llvm/ADT/Statistic.h"
 #include "llvm/ADT/SparseSet.h"
+#include "llvm/ADT/Statistic.h"
 #include "llvm/CodeGen/LiveIntervalAnalysis.h"
 #include "llvm/CodeGen/LiveStackAnalysis.h"
 #include "llvm/CodeGen/MachineFrameInfo.h"
@@ -37,9 +36,12 @@
 #include "llvm/Target/TargetInstrInfo.h"
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Target/TargetRegisterInfo.h"
+#include "llvm/Target/TargetSubtargetInfo.h"
 #include <algorithm>
 using namespace llvm;
 
+#define DEBUG_TYPE "regalloc"
+
 STATISTIC(NumSpillSlots, "Number of spill slots allocated");
 STATISTIC(NumIdCopies,   "Number of identity moves eliminated after rewriting");
 
@@ -53,8 +55,8 @@ INITIALIZE_PASS(VirtRegMap, "virtregmap", "Virtual Register Map", false, false)
 
 bool VirtRegMap::runOnMachineFunction(MachineFunction &mf) {
   MRI = &mf.getRegInfo();
-  TII = mf.getTarget().getInstrInfo();
-  TRI = mf.getTarget().getRegisterInfo();
+  TII = mf.getSubtarget().getInstrInfo();
+  TRI = mf.getSubtarget().getRegisterInfo();
   MF = &mf;
 
   Virt2PhysMap.clear();
@@ -169,9 +171,9 @@ public:
   static char ID;
   VirtRegRewriter() : MachineFunctionPass(ID) {}
 
-  virtual void getAnalysisUsage(AnalysisUsage &AU) const;
+  void getAnalysisUsage(AnalysisUsage &AU) const override;
 
-  virtual bool runOnMachineFunction(MachineFunction&);
+  bool runOnMachineFunction(MachineFunction&) override;
 };
 } // end anonymous namespace
 
@@ -204,8 +206,8 @@ void VirtRegRewriter::getAnalysisUsage(AnalysisUsage &AU) const {
 bool VirtRegRewriter::runOnMachineFunction(MachineFunction &fn) {
   MF = &fn;
   TM = &MF->getTarget();
-  TRI = TM->getRegisterInfo();
-  TII = TM->getInstrInfo();
+  TRI = TM->getSubtargetImpl()->getRegisterInfo();
+  TII = TM->getSubtargetImpl()->getInstrInfo();
   MRI = &MF->getRegInfo();
   Indexes = &getAnalysis<SlotIndexes>();
   LIS = &getAnalysis<LiveIntervals>();
@@ -278,6 +280,11 @@ void VirtRegRewriter::rewrite() {
   PhysRegs.clear();
   PhysRegs.setUniverse(TRI->getNumRegs());
 
+  // The function with uwtable should guarantee that the stack unwinder
+  // can unwind the stack to the previous frame.  Thus, we can't apply the
+  // noreturn optimization if the caller function has uwtable attribute.
+  bool HasUWTable = MF->getFunction()->hasFnAttribute(Attribute::UWTable);
+
   for (MachineFunction::iterator MBBI = MF->begin(), MBBE = MF->end();
        MBBI != MBBE; ++MBBI) {
     DEBUG(MBBI->print(dbgs(), Indexes));
@@ -287,9 +294,12 @@ void VirtRegRewriter::rewrite() {
       MachineInstr *MI = MII;
       ++MII;
 
-      // Check if this instruction is a call to a noreturn function.
-      // If so, all the definitions set by this instruction can be ignored.
-      if (IsExitBB && MI->isCall())
+      // Check if this instruction is a call to a noreturn function.  If this
+      // is a call to noreturn function and we don't need the stack unwinding
+      // functionality (i.e. this function does not have uwtable attribute and
+      // the callee function has the nounwind attribute), then we can ignore
+      // the definitions set by this instruction.
+      if (!HasUWTable && IsExitBB && MI->isCall()) {
         for (MachineInstr::mop_iterator MOI = MI->operands_begin(),
                MOE = MI->operands_end(); MOI != MOE; ++MOI) {
           MachineOperand &MO = *MOI;
@@ -305,6 +315,7 @@ void VirtRegRewriter::rewrite() {
           NoReturnInsts.insert(MI);
           break;
         }
+      }
 
       for (MachineInstr::mop_iterator MOI = MI->operands_begin(),
            MOE = MI->operands_end(); MOI != MOE; ++MOI) {
@@ -409,10 +420,8 @@ void VirtRegRewriter::rewrite() {
       // Check if this register has a use that will impact the rest of the
       // code. Uses in debug and noreturn instructions do not impact the
       // generated code.
-      for (MachineRegisterInfo::reg_nodbg_iterator It =
-             MRI->reg_nodbg_begin(Reg),
-             EndIt = MRI->reg_nodbg_end(); It != EndIt; ++It) {
-        if (!NoReturnInsts.count(&(*It))) {
+      for (MachineInstr &It : MRI->reg_nodbg_instructions(Reg)) {
+        if (!NoReturnInsts.count(&It)) {
           MRI->setPhysRegUsed(Reg);
           break;
         }