[llvm] Add a pass to collect dropped variable statistics (PR #102233)

[Adrian Prantl via llvm-commits]

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@@ -0,0 +1,586 @@
+//===- unittests/IR/DroppedVariableStatsTest.cpp - TimePassesHandler tests
+//----------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/AsmParser/Parser.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/InstIterator.h"
+#include "llvm/IR/LegacyPassManager.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Pass.h"
+#include "llvm/PassRegistry.h"
+#include "llvm/Passes/StandardInstrumentations.h"
+#include "llvm/Support/SourceMgr.h"
+#include "gtest/gtest.h"
+#include <gtest/gtest.h>
+#include <llvm/ADT/SmallString.h>
+#include <llvm/IR/LLVMContext.h>
+#include <llvm/IR/Module.h>
+#include <llvm/IR/PassInstrumentation.h>
+#include <llvm/IR/PassManager.h>
+#include <llvm/IR/PassTimingInfo.h>
+#include <llvm/Support/raw_ostream.h>
+
+using namespace llvm;
+namespace llvm {
+void initializePassTest1Pass(PassRegistry &);
+
+static std::unique_ptr<Module> parseIR(LLVMContext &C, const char *IR) {
+  SMDiagnostic Err;
+  std::unique_ptr<Module> Mod = parseAssemblyString(IR, Err, C);
+  if (!Mod)
+    Err.print("AbstractCallSiteTests", errs());
+  return Mod;
+}
+} // namespace llvm
+
+namespace {
+
+// This test ensures that if a #dbg_value and an instruction that exists in the
+// same scope as that #dbg_value are both deleted as a result of an optimization
+// pass, debug information is considered not dropped.
+TEST(DroppedVariableStats, BothDeleted) {
+  PassInstrumentationCallbacks PIC;
+  PassInstrumentation PI(&PIC);
+
+  LLVMContext C;
+
+  const char *IR =
+      "; Function Attrs: mustprogress nounwind ssp uwtable(sync)\n"
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adrian-prantl wrote:

how about using a modern C++ multiline string literal?

https://github.com/llvm/llvm-project/pull/102233