[DebugInfo] Add unit test for compact expression printer

Add a unit test for the compact DWARF expression printer which will be
used by the llvm-objdump --debug-vars option.

Differential revision: https://reviews.llvm.org/D75250

unittests/DebugInfo/DWARF/CMakeLists.txt

@@ -19,6 +19,7 @@ add_llvm_unittest(DebugInfoDWARFTests
   DWARFDebugInfoTest.cpp
   DWARFDebugLineTest.cpp
   DWARFDieTest.cpp
+  DWARFExpressionCompactPrinterTest.cpp
   DWARFFormValueTest.cpp
   DWARFLocationExpressionTest.cpp
   )

unittests/DebugInfo/DWARF/DWARFExpressionCompactPrinterTest.cpp

@@ -0,0 +1,76 @@
+//===- llvm/unittest/DebugInfo/DWARFExpressionCompactPrinterTest.cpp ------===//
+//
+// 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/ADT/ArrayRef.h"
+#include "llvm/DebugInfo/DWARF/DWARFContext.h"
+#include "llvm/DebugInfo/DWARF/DWARFDie.h"
+#include "llvm/DebugInfo/DWARF/DWARFExpression.h"
+#include "llvm/MC/MCInstrInfo.h"
+#include "llvm/Support/DataExtractor.h"
+#include "llvm/Support/TargetRegistry.h"
+#include "llvm/Support/TargetSelect.h"
+#include "llvm/Testing/Support/Error.h"
+#include "gtest/gtest.h"
+#include "DwarfGenerator.h"
+
+using namespace llvm;
+using namespace dwarf;
+
+namespace {
+class DWARFExpressionCompactPrinterTest : public ::testing::Test {
+public:
+  std::unique_ptr<MCRegisterInfo> MRI;
+
+  DWARFExpressionCompactPrinterTest() {
+    InitializeAllTargets();
+    InitializeAllTargetMCs();
+    InitializeAllAsmPrinters();
+
+    std::string TripleName = "armv8a-linux-gnueabi";
+    std::string ErrorStr;
+
+    const Target *TheTarget =
+        TargetRegistry::lookupTarget(TripleName, ErrorStr);
+
+    if (!TheTarget)
+      return;
+
+    MRI.reset(TheTarget->createMCRegInfo(TripleName));
+  }
+
+  void TestExprPrinter(ArrayRef<uint8_t> ExprData, StringRef Expected);
+};
+} // namespace
+
+void DWARFExpressionCompactPrinterTest::TestExprPrinter(
+    ArrayRef<uint8_t> ExprData, StringRef Expected) {
+  // If we didn't build ARM, do not run the test.
+  if (!MRI)
+    return;
+
+  // Print the expression, passing in the subprogram DIE, and check that the
+  // result is as expected.
+  std::string Result;
+  raw_string_ostream OS(Result);
+  DataExtractor DE(ExprData, true, 8);
+  DWARFExpression Expr(DE, 8);
+  Expr.printCompact(OS, *MRI);
+  EXPECT_EQ(OS.str(), Expected);
+}
+
+TEST_F(DWARFExpressionCompactPrinterTest, Test_OP_reg0) {
+  TestExprPrinter({DW_OP_reg0}, "R0");
+}
+
+TEST_F(DWARFExpressionCompactPrinterTest, Test_OP_reg10) {
+  TestExprPrinter({DW_OP_reg10}, "R10");
+}
+
+TEST_F(DWARFExpressionCompactPrinterTest, Test_OP_regx) {
+  TestExprPrinter({DW_OP_regx, 0x80, 0x02}, "D0");
+}