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Avoid accessing LLVM/DWARF register mappings if undefined 

Summary:
If the backend does not define LLVM/DWARF register mappings, the associated
variables are undefined since the map initializer is called by auto-generated
TableGen routines. This patch initializes the pointers and sizes to nullptr
and zero, respectively, and checks that they are valid before searching
for a mapping.

Reviewers: grosbach, dschuff

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D23458

llvm-svn: 278574
This commit is contained in:
Dominic Chen 2016-08-12 23:12:59 +00:00
parent c9c0d2dcb5
commit 2868fa171a
2 changed files with 14 additions and 0 deletions
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10
llvm/include/llvm/MC/MCRegisterInfo.h
View File

@ -271,6 +271,16 @@ public:
NumSubRegIndices = NumIndices;
SubRegIdxRanges = SubIdxRanges;
RegEncodingTable = RET;
// Initialize DWARF register mapping variables
EHL2DwarfRegs = nullptr;
EHL2DwarfRegsSize = 0;
L2DwarfRegs = nullptr;
L2DwarfRegsSize = 0;
EHDwarf2LRegs = nullptr;
EHDwarf2LRegsSize = 0;
Dwarf2LRegs = nullptr;
Dwarf2LRegsSize = 0;
}
/// \brief Used to initialize LLVM register to Dwarf

4
llvm/lib/MC/MCRegisterInfo.cpp
View File

@ -62,6 +62,8 @@ int MCRegisterInfo::getDwarfRegNum(unsigned RegNum, bool isEH) const {
const DwarfLLVMRegPair *M = isEH ? EHL2DwarfRegs : L2DwarfRegs;
unsigned Size = isEH ? EHL2DwarfRegsSize : L2DwarfRegsSize;
if (!M)
return -1;
DwarfLLVMRegPair Key = { RegNum, 0 };
const DwarfLLVMRegPair *I = std::lower_bound(M, M+Size, Key);
if (I == M+Size || I->FromReg != RegNum)
@ -73,6 +75,8 @@ int MCRegisterInfo::getLLVMRegNum(unsigned RegNum, bool isEH) const {
const DwarfLLVMRegPair *M = isEH ? EHDwarf2LRegs : Dwarf2LRegs;
unsigned Size = isEH ? EHDwarf2LRegsSize : Dwarf2LRegsSize;
if (!M)
return -1;
DwarfLLVMRegPair Key = { RegNum, 0 };
const DwarfLLVMRegPair *I = std::lower_bound(M, M+Size, Key);
assert(I != M+Size && I->FromReg == RegNum && "Invalid RegNum");