Silence more static analyzer warnings.

Add in definedness checks for shift operators, null checks when
pointers are assumed by the code to be non-null, and explicit
unreachables.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224255 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/ADT/BitVector.h

@@ -239,6 +239,7 @@ public:
   }
 
   BitVector &set(unsigned Idx) {
+    assert(Bits && "Bits never allocated");
     Bits[Idx / BITWORD_SIZE] |= BitWord(1) << (Idx % BITWORD_SIZE);
     return *this;
   }
@@ -546,6 +547,7 @@ private:
 
   void grow(unsigned NewSize) {
     Capacity = std::max(NumBitWords(NewSize), Capacity * 2);
+    assert(Capacity > 0 && "realloc-ing zero space");
     Bits = (BitWord *)std::realloc(Bits, Capacity * sizeof(BitWord));
 
     clear_unused_bits();

include/llvm/CodeGen/SelectionDAGNodes.h

@@ -768,6 +768,7 @@ protected:
     assert(NumValues == VTs.NumVTs &&
            "NumValues wasn't wide enough for its operands!");
     for (unsigned i = 0; i != Ops.size(); ++i) {
+      assert(OperandList && "no operands available");
       OperandList[i].setUser(this);
       OperandList[i].setInitial(Ops[i]);
     }

include/llvm/Object/COFF.h

@@ -276,12 +276,14 @@ public:
   }
 
   const StringTableOffset &getStringTableOffset() const {
+    assert(isSet() && "COFFSymbolRef points to nothing!");
     return CS16 ? CS16->Name.Offset : CS32->Name.Offset;
   }
 
   uint32_t getValue() const { return CS16 ? CS16->Value : CS32->Value; }
 
   int32_t getSectionNumber() const {
+    assert(isSet() && "COFFSymbolRef points to nothing!");
     if (CS16) {
       // Reserved sections are returned as negative numbers.
       if (CS16->SectionNumber <= COFF::MaxNumberOfSections16)
@@ -291,13 +293,18 @@ public:
     return static_cast<int32_t>(CS32->SectionNumber);
   }
 
-  uint16_t getType() const { return CS16 ? CS16->Type : CS32->Type; }
+  uint16_t getType() const {
+    assert(isSet() && "COFFSymbolRef points to nothing!");
+    return CS16 ? CS16->Type : CS32->Type;
+  }
 
   uint8_t getStorageClass() const {
+    assert(isSet() && "COFFSymbolRef points to nothing!");
     return CS16 ? CS16->StorageClass : CS32->StorageClass;
   }
 
   uint8_t getNumberOfAuxSymbols() const {
+    assert(isSet() && "COFFSymbolRef points to nothing!");
     return CS16 ? CS16->NumberOfAuxSymbols : CS32->NumberOfAuxSymbols;
   }
 
@@ -360,6 +367,8 @@ public:
   }
 
 private:
+  bool isSet() const { return CS16 || CS32; }
+
   const coff_symbol16 *CS16;
   const coff_symbol32 *CS32;
 };

lib/CodeGen/AsmPrinter/AsmPrinter.cpp

@@ -1492,10 +1492,12 @@ void AsmPrinter::EmitAlignment(unsigned NumBits, const GlobalObject *GV) const {
 
   if (NumBits == 0) return;   // 1-byte aligned: no need to emit alignment.
 
+  assert(NumBits < std::numeric_limits<unsigned>::digits &&
+         "undefined behavior");
   if (getCurrentSection()->getKind().isText())
-    OutStreamer.EmitCodeAlignment(1 << NumBits);
+    OutStreamer.EmitCodeAlignment(1u << NumBits);
   else
-    OutStreamer.EmitValueToAlignment(1 << NumBits);
+    OutStreamer.EmitValueToAlignment(1u << NumBits);
 }
 
 //===----------------------------------------------------------------------===//

lib/CodeGen/ExecutionDepsFix.cpp

@@ -74,6 +74,8 @@ struct DomainValue {
 
   // Is domain available?
   bool hasDomain(unsigned domain) const {
+    assert(domain < std::numeric_limits<unsigned>::digits &&
+           "undefined behavior");
     return AvailableDomains & (1u << domain);
   }
 
@@ -338,9 +340,11 @@ bool ExeDepsFix::merge(DomainValue *A, DomainValue *B) {
   // All uses of B are referred to A.
   B->Next = retain(A);
 
-  for (unsigned rx = 0; rx != NumRegs; ++rx)
+  for (unsigned rx = 0; rx != NumRegs; ++rx) {
+    assert(LiveRegs && "no space allocated for live registers");
     if (LiveRegs[rx].Value == B)
       setLiveReg(rx, A);
+  }
   return true;
 }
 
@@ -645,6 +649,7 @@ void ExeDepsFix::visitSoftInstr(MachineInstr *mi, unsigned mask) {
   SmallVector<LiveReg, 4> Regs;
   for (SmallVectorImpl<int>::iterator i=used.begin(), e=used.end(); i!=e; ++i) {
     int rx = *i;
+    assert(LiveRegs && "no space allocated for live registers");
     const LiveReg &LR = LiveRegs[rx];
     // This useless DomainValue could have been missed above.
     if (!LR.Value->getCommonDomains(available)) {
@@ -684,9 +689,11 @@ void ExeDepsFix::visitSoftInstr(MachineInstr *mi, unsigned mask) {
       continue;
 
     // If latest didn't merge, it is useless now. Kill all registers using it.
-    for (SmallVectorImpl<int>::iterator i=used.begin(), e=used.end(); i!=e; ++i)
-      if (LiveRegs[*i].Value == Latest)
-        kill(*i);
+    for (int i : used) {
+      assert(LiveRegs && "no space allocated for live registers");
+      if (LiveRegs[i].Value == Latest)
+        kill(i);
+    }
   }
 
   // dv is the DomainValue we are going to use for this instruction.

lib/CodeGen/MachineRegisterInfo.cpp

@@ -129,6 +129,7 @@ void MachineRegisterInfo::verifyUseList(unsigned Reg) const {
              << " use list MachineOperand " << MO
              << " has no parent instruction.\n";
       Valid = false;
+      continue;
     }
     MachineOperand *MO0 = &MI->getOperand(0);
     unsigned NumOps = MI->getNumOperands();

lib/CodeGen/RegisterClassInfo.cpp

@@ -47,6 +47,7 @@ void RegisterClassInfo::runOnMachineFunction(const MachineFunction &mf) {
   }
 
   // Does this MF have different CSRs?
+  assert(TRI && "no register info set");
   const MCPhysReg *CSR = TRI->getCalleeSavedRegs(MF);
   if (Update || CSR != CalleeSaved) {
     // Build a CSRNum map. Every CSR alias gets an entry pointing to the last
@@ -76,6 +77,7 @@ void RegisterClassInfo::runOnMachineFunction(const MachineFunction &mf) {
 /// registers filtered out. Volatile registers come first followed by CSR
 /// aliases ordered according to the CSR order specified by the target.
 void RegisterClassInfo::compute(const TargetRegisterClass *RC) const {
+  assert(RC && "no register class given");
   RCInfo &RCI = RegClass[RC->getID()];
 
   // Raw register count, including all reserved regs.

lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp

@@ -566,6 +566,7 @@ static void getCopyToPartsVector(SelectionDAG &DAG, SDLoc DL,
   } else if (NumParts > 0) {
     // If the intermediate type was expanded, split each the value into
     // legal parts.
+    assert(NumIntermediates != 0 && "division by zero");
     assert(NumParts % NumIntermediates == 0 &&
            "Must expand into a divisible number of parts!");
     unsigned Factor = NumParts / NumIntermediates;
@@ -1408,7 +1409,7 @@ SelectionDAGBuilder::EmitBranchForMergedCondition(const Value *Cond,
         if (TM.Options.NoNaNsFPMath)
           Condition = getFCmpCodeWithoutNaN(Condition);
       } else {
-        Condition = ISD::SETEQ; // silence warning.
+        (void)Condition; // silence warning.
         llvm_unreachable("Unknown compare instruction");
       }
 

lib/DebugInfo/DWARFDebugInfoEntry.cpp

@@ -76,7 +76,9 @@ void DWARFDebugInfoEntryMinimal::dump(raw_ostream &OS, DWARFUnit *u,
 static void dumpApplePropertyAttribute(raw_ostream &OS, uint64_t Val) {
   OS << " (";
   do {
-    uint64_t Bit = 1ULL << countTrailingZeros(Val);
+    uint64_t Shift = countTrailingZeros(Val);
+    assert(Shift < 64 && "undefined behavior");
+    uint64_t Bit = 1ULL << Shift;
     if (const char *PropName = ApplePropertyString(Bit))
       OS << PropName;
     else

lib/Object/IRObjectFile.cpp

@@ -181,6 +181,8 @@ void IRObjectFile::moveSymbolNext(DataRefImpl &Symb) const {
     Res = (Index << 2) | 3;
     break;
   }
+  default:
+    llvm_unreachable("unreachable case");
   }
 
   Symb.p = Res;

lib/Target/AArch64/MCTargetDesc/AArch64AddressingModes.h

@@ -236,6 +236,7 @@ static inline bool processLogicalImmediate(uint64_t Imm, unsigned RegSize,
 
   if (isShiftedMask_64(Imm)) {
     I = countTrailingZeros(Imm);
+    assert(I < 64 && "undefined behavior");
     CTO = CountTrailingOnes_64(Imm >> I);
   } else {
     Imm |= ~Mask;

lib/Target/AArch64/MCTargetDesc/AArch64ELFStreamer.cpp

@@ -177,7 +177,9 @@ private:
     MCELF::SetType(SD, ELF::STT_NOTYPE);
     MCELF::SetBinding(SD, ELF::STB_LOCAL);
     SD.setExternal(false);
-    Symbol->setSection(*getCurrentSection().first);
+    auto Sec = getCurrentSection().first;
+    assert(Sec && "need a section");
+    Symbol->setSection(*Sec);
 
     const MCExpr *Value = MCSymbolRefExpr::Create(Start, getContext());
     Symbol->setVariableValue(Value);

lib/Target/ARM/ARMISelLowering.cpp

@@ -8577,7 +8577,9 @@ static SDValue PerformBFICombine(SDNode *N,
     unsigned InvMask = cast<ConstantSDNode>(N->getOperand(2))->getZExtValue();
     unsigned LSB = countTrailingZeros(~InvMask);
     unsigned Width = (32 - countLeadingZeros(~InvMask)) - LSB;
-    unsigned Mask = (1 << Width)-1;
+    assert(Width < std::numeric_limits<unsigned>::digits &&
+           "undefined behavior");
+    unsigned Mask = (1u << Width) - 1;
     unsigned Mask2 = N11C->getZExtValue();
     if ((Mask & (~Mask2)) == 0)
       return DCI.DAG.getNode(ARMISD::BFI, SDLoc(N), N->getValueType(0),