IR / debug info: Add a DWOId field to DICompileUnit,

so DWARF skeleton CUs can be expression in IR. A skeleton CU is a
(typically empty) DW_TAG_compile_unit that has a DW_AT_(GNU)_dwo_name and
a DW_AT_(GNU)_dwo_id attribute. It is used to refer to external debug info.

This is a prerequisite for clang module debugging as discussed in
http://lists.cs.uiuc.edu/pipermail/cfe-dev/2014-November/040076.html.
In order to refer to external types stored in split DWARF (dwo) objects,
such as clang modules, we need to emit skeleton CUs, which identify the
dwarf object (i.e., the clang module) by filename (the SplitDebugFilename)
and a hash value, the dwo_id.

This patch only contains the IR changes. The idea is that a CUs with a
non-zero dwo_id field will be emitted together with a DW_AT_GNU_dwo_name
and DW_AT_GNU_dwo_id attribute.

http://reviews.llvm.org/D9488
rdar://problem/20091852

llvm-svn: 237949

1 files changed, 7 insertions, 5 deletions

diff --git a/llvm/lib/IR/LLVMContextImpl.h b/llvm/lib/IR/LLVMContextImpl.h
index 95292509f50..f81db607770 100644
--- a/llvm/lib/IR/LLVMContextImpl.h
+++ b/llvm/lib/IR/LLVMContextImpl.h
@@ -472,19 +472,20 @@ template <> struct MDNodeKeyImpl<DICompileUnit> {
   Metadata *Subprograms;
   Metadata *GlobalVariables;
   Metadata *ImportedEntities;
+  uint64_t DWOId;
 
   MDNodeKeyImpl(unsigned SourceLanguage, Metadata *File, StringRef Producer,
                 bool IsOptimized, StringRef Flags, unsigned RuntimeVersion,
                 StringRef SplitDebugFilename, unsigned EmissionKind,
                 Metadata *EnumTypes, Metadata *RetainedTypes,
                 Metadata *Subprograms, Metadata *GlobalVariables,
-                Metadata *ImportedEntities)
+                Metadata *ImportedEntities, uint64_t DWOId)
       : SourceLanguage(SourceLanguage), File(File), Producer(Producer),
         IsOptimized(IsOptimized), Flags(Flags), RuntimeVersion(RuntimeVersion),
         SplitDebugFilename(SplitDebugFilename), EmissionKind(EmissionKind),
         EnumTypes(EnumTypes), RetainedTypes(RetainedTypes),
         Subprograms(Subprograms), GlobalVariables(GlobalVariables),
-        ImportedEntities(ImportedEntities) {}
+        ImportedEntities(ImportedEntities), DWOId(DWOId) {}
   MDNodeKeyImpl(const DICompileUnit *N)
       : SourceLanguage(N->getSourceLanguage()), File(N->getRawFile()),
         Producer(N->getProducer()), IsOptimized(N->isOptimized()),
@@ -494,7 +495,7 @@ template <> struct MDNodeKeyImpl<DICompileUnit> {
         RetainedTypes(N->getRawRetainedTypes()),
         Subprograms(N->getRawSubprograms()),
         GlobalVariables(N->getRawGlobalVariables()),
-        ImportedEntities(N->getRawImportedEntities()) {}
+        ImportedEntities(N->getRawImportedEntities()), DWOId(N->getDWOId()) {}
 
   bool isKeyOf(const DICompileUnit *RHS) const {
     return SourceLanguage == RHS->getSourceLanguage() &&
@@ -507,13 +508,14 @@ template <> struct MDNodeKeyImpl<DICompileUnit> {
            RetainedTypes == RHS->getRawRetainedTypes() &&
            Subprograms == RHS->getRawSubprograms() &&
            GlobalVariables == RHS->getRawGlobalVariables() &&
-           ImportedEntities == RHS->getRawImportedEntities();
+           ImportedEntities == RHS->getRawImportedEntities() &&
+           DWOId == RHS->getDWOId();
   }
   unsigned getHashValue() const {
     return hash_combine(SourceLanguage, File, Producer, IsOptimized, Flags,
                         RuntimeVersion, SplitDebugFilename, EmissionKind,
                         EnumTypes, RetainedTypes, Subprograms, GlobalVariables,
-                        ImportedEntities);
+                        ImportedEntities, DWOId);
   }
 };