Add MCRI::getNumSubRegIndices() and start checking SubRegIndex ranges.

Apparently, NumSubRegIndices was completely unused before. Adjust it by
one to include the null subreg index, just like getNumRegs() includes
the null register.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163628 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 3 insertions, 0 deletions

diff --git a/lib/MC/MCRegisterInfo.cpp b/lib/MC/MCRegisterInfo.cpp
index 4d1aff3e427..5c71106c901 100644
--- a/lib/MC/MCRegisterInfo.cpp
+++ b/lib/MC/MCRegisterInfo.cpp
@@ -24,6 +24,8 @@ unsigned MCRegisterInfo::getMatchingSuperReg(unsigned Reg, unsigned SubIdx,
 }
 
 unsigned MCRegisterInfo::getSubReg(unsigned Reg, unsigned Idx) const {
+  assert(Idx && Idx < getNumSubRegIndices() &&
+         "This is not a subregister index");
   // Get a pointer to the corresponding SubRegIndices list. This list has the
   // name of each sub-register in the same order as MCSubRegIterator.
   const uint16_t *SRI = SubRegIndices + get(Reg).SubRegIndices;
@@ -34,6 +36,7 @@ unsigned MCRegisterInfo::getSubReg(unsigned Reg, unsigned Idx) const {
 }
 
 unsigned MCRegisterInfo::getSubRegIndex(unsigned Reg, unsigned SubReg) const {
+  assert(SubReg && SubReg < getNumRegs() && "This is not a register");
   // Get a pointer to the corresponding SubRegIndices list. This list has the
   // name of each sub-register in the same order as MCSubRegIterator.
   const uint16_t *SRI = SubRegIndices + get(Reg).SubRegIndices;