arm: Fixed undefined behaviours identified by gcc

This patch fixes the runtime errors highlighted by the undefined
behaviour sanitizer. In the end there were two issues. First, when
rotating an immediate, we ended up shifting an uint32_t by 32 in some
cases. This case is fixed by checking for a rotation by 0
positions. Second, the Mrc15 and Mcr15 are operating on an IntReg and
a MiscReg, but we used the type RegRegImmOp and passed a MiscRegIndex
as an IntRegIndex. This issue is resolved by introducing a
MiscRegRegImmOp and RegMiscRegImmOp with the appropriate types.

With these fixes there are no runtime errors identified for the full
ARM regressions.

3 files changed, 62 insertions, 3 deletions

diff --git a/src/arch/arm/insts/misc.cc b/src/arch/arm/insts/misc.cc
index efc334c4b..7432f436e 100644
--- a/src/arch/arm/insts/misc.cc
+++ b/src/arch/arm/insts/misc.cc
@@ -256,6 +256,30 @@ RegRegImmOp::generateDisassembly(Addr pc, const SymbolTable *symtab) const
 }
 
 std::string
+MiscRegRegImmOp::generateDisassembly(Addr pc, const SymbolTable *symtab) const
+{
+    std::stringstream ss;
+    printMnemonic(ss);
+    printReg(ss, dest);
+    ss << ", ";
+    printReg(ss, op1);
+    ccprintf(ss, ", #%d", imm);
+    return ss.str();
+}
+
+std::string
+RegMiscRegImmOp::generateDisassembly(Addr pc, const SymbolTable *symtab) const
+{
+    std::stringstream ss;
+    printMnemonic(ss);
+    printReg(ss, dest);
+    ss << ", ";
+    printReg(ss, op1);
+    ccprintf(ss, ", #%d", imm);
+    return ss.str();
+}
+
+std::string
 RegImmImmOp::generateDisassembly(Addr pc, const SymbolTable *symtab) const
 {
     std::stringstream ss;
diff --git a/src/arch/arm/insts/misc.hh b/src/arch/arm/insts/misc.hh
index 3d947a272..4217dc6f1 100644
--- a/src/arch/arm/insts/misc.hh
+++ b/src/arch/arm/insts/misc.hh
@@ -256,6 +256,40 @@ class RegRegImmOp : public PredOp
     std::string generateDisassembly(Addr pc, const SymbolTable *symtab) const;
 };
 
+class MiscRegRegImmOp : public PredOp
+{
+  protected:
+    MiscRegIndex dest;
+    IntRegIndex op1;
+    uint64_t imm;
+
+    MiscRegRegImmOp(const char *mnem, ExtMachInst _machInst, OpClass __opClass,
+                    MiscRegIndex _dest, IntRegIndex _op1,
+                    uint64_t _imm) :
+        PredOp(mnem, _machInst, __opClass),
+        dest(_dest), op1(_op1), imm(_imm)
+    {}
+
+    std::string generateDisassembly(Addr pc, const SymbolTable *symtab) const;
+};
+
+class RegMiscRegImmOp : public PredOp
+{
+  protected:
+    IntRegIndex dest;
+    MiscRegIndex op1;
+    uint64_t imm;
+
+    RegMiscRegImmOp(const char *mnem, ExtMachInst _machInst, OpClass __opClass,
+                    IntRegIndex _dest, MiscRegIndex _op1,
+                    uint64_t _imm) :
+        PredOp(mnem, _machInst, __opClass),
+        dest(_dest), op1(_op1), imm(_imm)
+    {}
+
+    std::string generateDisassembly(Addr pc, const SymbolTable *symtab) const;
+};
+
 class RegImmImmOp : public PredOp
 {
   protected:
diff --git a/src/arch/arm/insts/pred_inst.hh b/src/arch/arm/insts/pred_inst.hh
index c5e2ab386..8a335879b 100644
--- a/src/arch/arm/insts/pred_inst.hh
+++ b/src/arch/arm/insts/pred_inst.hh
@@ -48,10 +48,11 @@
 namespace ArmISA
 {
 static inline uint32_t
-rotate_imm(uint32_t immValue, int rotateValue)
+rotate_imm(uint32_t immValue, uint32_t rotateValue)
 {
-    return ((immValue >> (rotateValue & 31)) |
-            (immValue << (32 - (rotateValue & 31))));
+    rotateValue &= 31;
+    return rotateValue == 0 ? immValue :
+        (immValue >> rotateValue) | (immValue << (32 - rotateValue));
 }
 
 static inline uint32_t