Revert "Revert "Debug Info: Type Units: Simplify type hashing using IR-provided unique names.""

This reverts commit r198398, thus reapplying r198397.

I had accidentally introduced an endianness issue when applying the hash
to the type unit. Using support::ulittle64_t in the reinterpret_cast in
addDwarfTypeUnitType fixes this issue.

Original commit message:

Debug Info: Type Units: Simplify type hashing using IR-provided unique
names.

What's good for LTO metadata size problems ought to be good for non-LTO
debug info size too, so let's rely on the same uniqueness in both cases.
If it's insufficient for non-LTO for whatever reason (since we now won't
be uniquing CU-local types or any C types - but these are likely to not
be the most significant contributors to type bloat) we should consider a
frontend solution that'll help both LTO and non-LTO alike, rather than
using DWARF-level DIE-hashing that only helps non-LTO debug info size.

It's also much simpler this way and benefits C++ even more since we can
deduplicate lexically separate definitions of the same C++ type since
they have the same mangled name.

llvm-svn: 198436

1 files changed, 2 insertions, 1 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
index b81688ea3f0..84d9cae7a1d 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
@@ -695,7 +695,8 @@ public:
 
   /// \brief Add a DIE to the set of types that we're going to pull into
   /// type units.
-  void addDwarfTypeUnitType(uint16_t Language, DIE *Die, DICompositeType CTy);
+  void addDwarfTypeUnitType(uint16_t Language, StringRef Identifier, DIE *Die,
+                            DICompositeType CTy);
 
   /// \brief Add a label so that arange data can be generated for it.
   void addArangeLabel(SymbolCU SCU) { ArangeLabels.push_back(SCU); }