Reapply "[RemoveDIs] Load into new debug info format by default in LLVM (#89799)"

Fixes the broken tests in the original commit:
  2f01fd99eb8c8ab3db9aba72c4f00e31e9e60a05

This will probably break some downstream tools that don't already handle
debug records. If your downstream code breaks as a result of this
change, the simplest fix is to convert the module in question to the old
debug format before you process it, using
`Module::convertFromNewDbgValues()`. For more information about how to
handle debug records or about what has changed, see the migration
document:
  https://llvm.org/docs/RemoveDIsDebugInfo.html

This reverts commit 00821fed09969305b0003d3313c44d1e761a7131.

4 files changed, 9 insertions, 5 deletions

diff --git a/llvm/lib/IR/BasicBlock.cpp b/llvm/lib/IR/BasicBlock.cpp
index 29f2cbf..aea9425 100644
--- a/llvm/lib/IR/BasicBlock.cpp
+++ b/llvm/lib/IR/BasicBlock.cpp
@@ -181,7 +181,7 @@ template class llvm::SymbolTableListTraits<Instruction,
 BasicBlock::BasicBlock(LLVMContext &C, const Twine &Name, Function *NewParent,
                        BasicBlock *InsertBefore)
     : Value(Type::getLabelTy(C), Value::BasicBlockVal),
-      IsNewDbgInfoFormat(false), Parent(nullptr) {
+      IsNewDbgInfoFormat(UseNewDbgInfoFormat), Parent(nullptr) {
 
   if (NewParent)
     insertInto(NewParent, InsertBefore);
diff --git a/llvm/lib/IR/DebugProgramInstruction.cpp b/llvm/lib/IR/DebugProgramInstruction.cpp
index fbca7cd..9a4926c 100644
--- a/llvm/lib/IR/DebugProgramInstruction.cpp
+++ b/llvm/lib/IR/DebugProgramInstruction.cpp
@@ -366,8 +366,8 @@ void DbgVariableRecord::setKillLocation() {
 }
 
 bool DbgVariableRecord::isKillLocation() const {
-  return (getNumVariableLocationOps() == 0 &&
-          !getExpression()->isComplex()) ||
+  return (!hasArgList() && isa<MDNode>(getRawLocation())) ||
+         (getNumVariableLocationOps() == 0 && !getExpression()->isComplex()) ||
          any_of(location_ops(), [](Value *V) { return isa<UndefValue>(V); });
 }
 
diff --git a/llvm/lib/IR/Function.cpp b/llvm/lib/IR/Function.cpp
index 6901840..e42248d 100644
--- a/llvm/lib/IR/Function.cpp
+++ b/llvm/lib/IR/Function.cpp
@@ -83,6 +83,8 @@ static cl::opt<unsigned> NonGlobalValueMaxNameSize(
     "non-global-value-max-name-size", cl::Hidden, cl::init(1024),
     cl::desc("Maximum size for the name of non-global values."));
 
+extern cl::opt<bool> UseNewDbgInfoFormat;
+
 void Function::convertToNewDbgValues() {
   IsNewDbgInfoFormat = true;
   for (auto &BB : *this) {
@@ -438,7 +440,7 @@ Function::Function(FunctionType *Ty, LinkageTypes Linkage, unsigned AddrSpace,
     : GlobalObject(Ty, Value::FunctionVal,
                    OperandTraits<Function>::op_begin(this), 0, Linkage, name,
                    computeAddrSpace(AddrSpace, ParentModule)),
-      NumArgs(Ty->getNumParams()), IsNewDbgInfoFormat(false) {
+      NumArgs(Ty->getNumParams()), IsNewDbgInfoFormat(UseNewDbgInfoFormat) {
   assert(FunctionType::isValidReturnType(getReturnType()) &&
          "invalid return type");
   setGlobalObjectSubClassData(0);
diff --git a/llvm/lib/IR/Module.cpp b/llvm/lib/IR/Module.cpp
index a8696ed..915fa50 100644
--- a/llvm/lib/IR/Module.cpp
+++ b/llvm/lib/IR/Module.cpp
@@ -54,6 +54,8 @@
 
 using namespace llvm;
 
+extern cl::opt<bool> UseNewDbgInfoFormat;
+
 //===----------------------------------------------------------------------===//
 // Methods to implement the globals and functions lists.
 //
@@ -72,7 +74,7 @@ template class llvm::SymbolTableListTraits<GlobalIFunc>;
 Module::Module(StringRef MID, LLVMContext &C)
     : Context(C), ValSymTab(std::make_unique<ValueSymbolTable>(-1)),
       ModuleID(std::string(MID)), SourceFileName(std::string(MID)), DL(""),
-      IsNewDbgInfoFormat(false) {
+      IsNewDbgInfoFormat(UseNewDbgInfoFormat) {
   Context.addModule(this);
 }