[DebugInfo] Improvements to representation of enumeration types (PR36168)

This patch is the LLVM part of fixing the issues, described in
https://bugs.llvm.org/show_bug.cgi?id=36168

* The representation of enumerator values in the debug info metadata now
  contains a boolean flag isUnsigned, which determines how the bits of
  the value are interpreted.
* The DW_TAG_enumeration type DIE now always (for DWARF version >= 3)
  includes a DW_AT_type attribute, which refers to the underlying
  integer type, as suggested in DWARFv4 (5.7 Enumeration Type Entries).
* The debug info metadata for enumeration type contains (in flags)
  indication whether this is a C++11 "fixed enum".
* For C++11 enumeration with a fixed underlying type, the DIE also
  includes the DW_AT_enum_class attribute (for DWARF version >= 4).
* Encoding of enumerator constants uses DW_FORM_sdata for signed values
  and DW_FORM_udata for unsigned values, as suggested by DWARFv4 (7.5.4
  Attribute Encodings).

The changes should be backwards compatible:

* the isUnsigned attribute is optional and defaults to false.
* if the underlying type for the enumeration is not available, the
  enumerator values are considered signed.
* the FixedEnum flag defaults to clear.
* the bitcode format for DIEnumerator stores the unsigned flag bit #1 of
  the first record element, so the format does not change and the zero
  previously stored there is consistent with the false default for
  IsUnsigned.

Differential Revision: https://reviews.llvm.org/D42734


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@324489 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 6 insertions, 4 deletions

diff --git a/unittests/IR/MetadataTest.cpp b/unittests/IR/MetadataTest.cpp
index 548456cc501..6c16951f851 100644
--- a/unittests/IR/MetadataTest.cpp
+++ b/unittests/IR/MetadataTest.cpp
@@ -978,14 +978,16 @@ TEST_F(DISubrangeTest, getVariableCount) {
 typedef MetadataTest DIEnumeratorTest;
 
 TEST_F(DIEnumeratorTest, get) {
-  auto *N = DIEnumerator::get(Context, 7, "name");
+  auto *N = DIEnumerator::get(Context, 7, false, "name");
   EXPECT_EQ(dwarf::DW_TAG_enumerator, N->getTag());
   EXPECT_EQ(7, N->getValue());
+  EXPECT_EQ(false, N->isUnsigned());
   EXPECT_EQ("name", N->getName());
-  EXPECT_EQ(N, DIEnumerator::get(Context, 7, "name"));
+  EXPECT_EQ(N, DIEnumerator::get(Context, 7, false, "name"));
 
-  EXPECT_NE(N, DIEnumerator::get(Context, 8, "name"));
-  EXPECT_NE(N, DIEnumerator::get(Context, 7, "nam"));
+  EXPECT_NE(N, DIEnumerator::get(Context, 7, true, "name"));
+  EXPECT_NE(N, DIEnumerator::get(Context, 8, false, "name"));
+  EXPECT_NE(N, DIEnumerator::get(Context, 7, false, "nam"));
 
   TempDIEnumerator Temp = N->clone();
   EXPECT_EQ(N, MDNode::replaceWithUniqued(std::move(Temp)));