Implement @llvm.returnaddress. rdar://8015977.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@104421 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 21 insertions, 5 deletions

diff --git a/lib/Target/ARM/Thumb1InstrInfo.cpp b/lib/Target/ARM/Thumb1InstrInfo.cpp
index f0f46bf3f8..fae84d4ee0 100644
--- a/lib/Target/ARM/Thumb1InstrInfo.cpp
+++ b/lib/Target/ARM/Thumb1InstrInfo.cpp
@@ -17,6 +17,7 @@
 #include "ARMMachineFunctionInfo.h"
 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/CodeGen/MachineMemOperand.h"
 #include "llvm/CodeGen/PseudoSourceValue.h"
 #include "llvm/ADT/SmallVector.h"
@@ -150,7 +151,8 @@ loadRegFromStackSlot(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
 bool Thumb1InstrInfo::
 spillCalleeSavedRegisters(MachineBasicBlock &MBB,
                           MachineBasicBlock::iterator MI,
-                          const std::vector<CalleeSavedInfo> &CSI) const {
+                          const std::vector<CalleeSavedInfo> &CSI,
+                          const TargetRegisterInfo *TRI) const {
   if (CSI.empty())
     return false;
 
@@ -161,9 +163,22 @@ spillCalleeSavedRegisters(MachineBasicBlock &MBB,
   AddDefaultPred(MIB);
   for (unsigned i = CSI.size(); i != 0; --i) {
     unsigned Reg = CSI[i-1].getReg();
-    // Add the callee-saved register as live-in. It's killed at the spill.
-    MBB.addLiveIn(Reg);
-    MIB.addReg(Reg, RegState::Kill);
+    bool isKill = true;
+
+    // Add the callee-saved register as live-in unless it's LR and
+    // @llvm.returnaddress is called. If LR is returned for @llvm.returnaddress
+    // then it's already added to the function and entry block live-in sets.
+    if (Reg == ARM::LR) {
+      MachineFunction &MF = *MBB.getParent();
+      if (MF.getFrameInfo()->isReturnAddressTaken() &&
+          MF.getRegInfo().isLiveIn(Reg))
+        isKill = false;
+    }
+
+    if (isKill) {
+      MBB.addLiveIn(Reg);
+      MIB.addReg(Reg, RegState::Kill);
+    }
   }
   return true;
 }
@@ -171,7 +186,8 @@ spillCalleeSavedRegisters(MachineBasicBlock &MBB,
 bool Thumb1InstrInfo::
 restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
                             MachineBasicBlock::iterator MI,
-                            const std::vector<CalleeSavedInfo> &CSI) const {
+                            const std::vector<CalleeSavedInfo> &CSI,
+                            const TargetRegisterInfo *TRI) const {
   MachineFunction &MF = *MBB.getParent();
   ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
   if (CSI.empty())