CodeGen: Assert that inlined-at locations agree

As a follow-up to r234021, assert that a debug info intrinsic variable's
`MDLocalVariable::getInlinedAt()` always matches the
`MDLocation::getInlinedAt()` of its `!dbg` attachment.

The goal here is to get rid of `MDLocalVariable::getInlinedAt()`
entirely (PR22778), but I'll let these assertions bake for a while
first.

If you have an out-of-tree backend that just broke, you're probably
attaching the wrong `DebugLoc` to a `DBG_VALUE` instruction.  The one
you want is the location that was attached to the corresponding
`@llvm.dbg.declare` or `@llvm.dbg.value` call that you started with.

llvm-svn: 234038

1 files changed, 8 insertions, 5 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index 3de9c26a905..c56b5f46a53 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -501,12 +501,14 @@ bool SelectionDAGISel::runOnMachineFunction(MachineFunction &mf) {
       MachineBasicBlock::iterator InsertPos = Def;
       const MDNode *Variable = MI->getDebugVariable();
       const MDNode *Expr = MI->getDebugExpression();
+      DebugLoc DL = MI->getDebugLoc();
       bool IsIndirect = MI->isIndirectDebugValue();
       unsigned Offset = IsIndirect ? MI->getOperand(1).getImm() : 0;
+      assert(DIVariable(Variable)->isValidLocationForIntrinsic(DL) &&
+             "Expected inlined-at fields to agree");
       // Def is never a terminator here, so it is ok to increment InsertPos.
-      BuildMI(*EntryMBB, ++InsertPos, MI->getDebugLoc(),
-              TII->get(TargetOpcode::DBG_VALUE), IsIndirect, LDI->second, Offset,
-              Variable, Expr);
+      BuildMI(*EntryMBB, ++InsertPos, DL, TII->get(TargetOpcode::DBG_VALUE),
+              IsIndirect, LDI->second, Offset, Variable, Expr);
 
       // If this vreg is directly copied into an exported register then
       // that COPY instructions also need DBG_VALUE, if it is the only
@@ -524,9 +526,10 @@ bool SelectionDAGISel::runOnMachineFunction(MachineFunction &mf) {
         CopyUseMI = nullptr; break;
       }
       if (CopyUseMI) {
+        // Use MI's debug location, which describes where Variable was
+        // declared, rather than whatever is attached to CopyUseMI.
         MachineInstr *NewMI =
-            BuildMI(*MF, CopyUseMI->getDebugLoc(),
-                    TII->get(TargetOpcode::DBG_VALUE), IsIndirect,
+            BuildMI(*MF, DL, TII->get(TargetOpcode::DBG_VALUE), IsIndirect,
                     CopyUseMI->getOperand(0).getReg(), Offset, Variable, Expr);
         MachineBasicBlock::iterator Pos = CopyUseMI;
         EntryMBB->insertAfter(Pos, NewMI);