Revert "3rd Reapply "[DebugInfo] Use variadic debug values to salvage BinOps and GEP instrs with non-const operands""

> This reapplies c0f3dfb9, which was reverted following the discovery of
> crashes on linux kernel and chromium builds - these issues have since
> been fixed, allowing this patch to re-land.

This reverts commit 36ec97f76ac0d8be76fb16ac521f55126766267d.

The change caused non-determinism in the compiler, see comments on the code
review at https://reviews.llvm.org/D91722.

Reverting to unbreak people's builds until that can be addressed.

This also reverts the follow-up "[DebugInfo] Limit the number of values
that may be referenced by a dbg.value" in
a0bd6105d80698c53ceaa64bbe6e3b7e7bbf99ee.

1 files changed, 3 insertions, 12 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 01b0627..696a28a 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -1248,10 +1248,6 @@ void SelectionDAGBuilder::resolveDanglingDebugInfo(const Value *V,
 }
 
 void SelectionDAGBuilder::salvageUnresolvedDbgValue(DanglingDebugInfo &DDI) {
-  // TODO: For the variadic implementation, instead of only checking the fail
-  // state of `handleDebugValue`, we need know specifically which values were
-  // invalid, so that we attempt to salvage only those values when processing
-  // a DIArgList.
   assert(!DDI.getDI()->hasArgList() &&
          "Not implemented for variadic dbg_values");
   Value *V = DDI.getDI()->getValue(0);
@@ -1275,21 +1271,16 @@ void SelectionDAGBuilder::salvageUnresolvedDbgValue(DanglingDebugInfo &DDI) {
   while (isa<Instruction>(V)) {
     Instruction &VAsInst = *cast<Instruction>(V);
     // Temporary "0", awaiting real implementation.
-    SmallVector<Value *, 4> AdditionalValues;
-    DIExpression *SalvagedExpr =
-        salvageDebugInfoImpl(VAsInst, Expr, StackValue, 0, AdditionalValues);
+    DIExpression *NewExpr = salvageDebugInfoImpl(VAsInst, Expr, StackValue, 0);
 
     // If we cannot salvage any further, and haven't yet found a suitable debug
     // expression, bail out.
-    // TODO: If AdditionalValues isn't empty, then the salvage can only be
-    // represented with a DBG_VALUE_LIST, so we give up. When we have support
-    // here for variadic dbg_values, remove that condition.
-    if (!SalvagedExpr || !AdditionalValues.empty())
+    if (!NewExpr)
       break;
 
     // New value and expr now represent this debuginfo.
     V = VAsInst.getOperand(0);
-    Expr = SalvagedExpr;
+    Expr = NewExpr;
 
     // Some kind of simplification occurred: check whether the operand of the
     // salvaged debug expression can be encoded in this DAG.