Verify slot index ordering.

The slot indexes must be monotonically increasing through the function.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123324 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/MachineVerifier.cpp b/lib/CodeGen/MachineVerifier.cpp
index cceb4b6..ad93f9c 100644
--- a/lib/CodeGen/MachineVerifier.cpp
+++ b/lib/CodeGen/MachineVerifier.cpp
@@ -74,6 +74,8 @@
     RegVector regsDefined, regsDead, regsKilled;
     RegSet regsLiveInButUnused;
 
+    SlotIndex lastIndex;
+
     // Add Reg and any sub-registers to RV
     void addRegWithSubRegs(RegVector &RV, unsigned Reg) {
       RV.push_back(Reg);
@@ -356,6 +358,7 @@
 }
 
 void MachineVerifier::visitMachineFunctionBefore() {
+  lastIndex = SlotIndex();
   regsReserved = TRI->getReservedRegs(*MF);
 
   // A sub-register of a reserved register is also reserved
@@ -524,6 +527,9 @@
 
   regsKilled.clear();
   regsDefined.clear();
+
+  if (Indexes)
+    lastIndex = Indexes->getMBBStartIdx(MBB);
 }
 
 void MachineVerifier::visitMachineInstrBefore(const MachineInstr *MI) {
@@ -793,12 +799,31 @@
   set_subtract(regsLive, regsKilled); regsKilled.clear();
   set_subtract(regsLive, regsDead);   regsDead.clear();
   set_union(regsLive, regsDefined);   regsDefined.clear();
+
+  if (Indexes && Indexes->hasIndex(MI)) {
+    SlotIndex idx = Indexes->getInstructionIndex(MI);
+    if (!(idx > lastIndex)) {
+      report("Instruction index out of order", MI);
+      *OS << "Last instruction was at " << lastIndex << '\n';
+    }
+    lastIndex = idx;
+  }
 }
 
 void
 MachineVerifier::visitMachineBasicBlockAfter(const MachineBasicBlock *MBB) {
   MBBInfoMap[MBB].regsLiveOut = regsLive;
   regsLive.clear();
+
+  if (Indexes) {
+    SlotIndex stop = Indexes->getMBBEndIdx(MBB);
+    if (!(stop > lastIndex)) {
+      report("Block ends before last instruction index", MBB);
+      *OS << "Block ends at " << stop
+          << " last instruction was at " << lastIndex << '\n';
+    }
+    lastIndex = stop;
+  }
 }
 
 // Calculate the largest possible vregsPassed sets. These are the registers that