Reapply r128045 and r128051 with fixes.
This will extend the ranges of debug info variables in registers until they are
clobbered.
Fix 1: Don't mistake DBG_VALUE instructions referring to incoming arguments on
the stack with DBG_VALUE instructions referring to variables in the frame
pointer. This fixes the gdb test-suite failure.
Fix 2: Don't trace through copies to physical registers setting up call
arguments. These registers are call clobbered, and the source register is more
likely to be a callee-saved register that can be extended through the call
instruction.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128114 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/LiveDebugVariables.cpp b/lib/CodeGen/LiveDebugVariables.cpp
index 20e997a..333d15f 100644
--- a/lib/CodeGen/LiveDebugVariables.cpp
+++ b/lib/CodeGen/LiveDebugVariables.cpp
@@ -101,10 +101,6 @@
void insertDebugValue(MachineBasicBlock *MBB, SlotIndex Idx, unsigned LocNo,
LiveIntervals &LIS, const TargetInstrInfo &TII);
- /// insertDebugKill - Insert an undef DBG_VALUE into MBB at Idx.
- void insertDebugKill(MachineBasicBlock *MBB, SlotIndex Idx,
- LiveIntervals &LIS, const TargetInstrInfo &TII);
-
public:
/// UserValue - Create a new UserValue.
UserValue(const MDNode *var, unsigned o, DebugLoc L,
@@ -515,6 +511,13 @@
MachineInstr *MI = &*UI;
unsigned DstReg = MI->getOperand(0).getReg();
+ // Don't follow copies to physregs. These are usually setting up call
+ // arguments, and the argument registers are always call clobbered. We are
+ // better off in the source register which could be a callee-saved register,
+ // or it could be spilled.
+ if (!TargetRegisterInfo::isVirtualRegister(DstReg))
+ continue;
+
// Is LocNo extended to reach this copy? If not, another def may be blocking
// it, or we are looking at a wrong value of LI.
SlotIndex Idx = LIS.getInstructionIndex(MI);
@@ -752,13 +755,6 @@
.addOperand(Loc).addImm(offset).addMetadata(variable);
}
-void UserValue::insertDebugKill(MachineBasicBlock *MBB, SlotIndex Idx,
- LiveIntervals &LIS, const TargetInstrInfo &TII) {
- MachineBasicBlock::iterator I = findInsertLocation(MBB, Idx, LIS);
- BuildMI(*MBB, I, findDebugLoc(), TII.get(TargetOpcode::DBG_VALUE)).addReg(0)
- .addImm(offset).addMetadata(variable);
-}
-
void UserValue::emitDebugValues(VirtRegMap *VRM, LiveIntervals &LIS,
const TargetInstrInfo &TII) {
MachineFunction::iterator MFEnd = VRM->getMachineFunction().end();
@@ -790,12 +786,6 @@
break;
++I;
- if (Stop == MBBEnd)
- continue;
- // The current interval ends before MBB.
- // Insert a kill if there is a gap.
- if (!I.valid() || I.start() > Stop)
- insertDebugKill(MBB, Stop, LIS, TII);
}
}