[mips] Use correct frame register for DWARF info when dynamically realigning the stack.

Summary:
This patch overrides TargetFrameLowering::getFrameIndexReference() in order to
specify the correct register when the function needs dynamic stack realignment.
The values returned from this function are used in order to create DW_AT_locations
for DWARF info. These locations would use the wrong registers as it's been
reported in PR25028.

Reviewers: dsanders

Subscribers: dean, llvm-commits

Differential Revision: http://reviews.llvm.org/D13511

llvm-svn: 252882

1 files changed, 15 insertions, 0 deletions

diff --git a/llvm/lib/Target/Mips/MipsSEFrameLowering.cpp b/llvm/lib/Target/Mips/MipsSEFrameLowering.cpp
index 297e7a2ec8b..a4abd62ee60 100644
--- a/llvm/lib/Target/Mips/MipsSEFrameLowering.cpp
+++ b/llvm/lib/Target/Mips/MipsSEFrameLowering.cpp
@@ -753,6 +753,21 @@ void MipsSEFrameLowering::emitInterruptEpilogueStub(
       .addImm(0);
 }
 
+int MipsSEFrameLowering::getFrameIndexReference(const MachineFunction &MF,
+                                                int FI,
+                                                unsigned &FrameReg) const {
+  const MachineFrameInfo *MFI = MF.getFrameInfo();
+  MipsABIInfo ABI = STI.getABI();
+
+  if (MFI->isFixedObjectIndex(FI))
+    FrameReg = hasFP(MF) ? ABI.GetFramePtr() : ABI.GetStackPtr();
+  else
+    FrameReg = hasBP(MF) ? ABI.GetBasePtr() : ABI.GetStackPtr();
+
+  return MFI->getObjectOffset(FI) + MFI->getStackSize() -
+         getOffsetOfLocalArea() + MFI->getOffsetAdjustment();
+}
+
 bool MipsSEFrameLowering::
 spillCalleeSavedRegisters(MachineBasicBlock &MBB,
                           MachineBasicBlock::iterator MI,