Debug Info: remove duplication of DIEs when a DIE is part of the type system

and it is shared across CUs.

We add a few maps in DwarfDebug to map MDNodes for the type system to the
corresponding DIEs: MDTypeNodeToDieMap, MDSPNodeToDieMap, and
MDStaticMemberNodeToDieMap. These DIEs can be shared across CUs, that is why we
keep the maps in DwarfDebug instead of CompileUnit.

Sometimes, when we try to add an attribute to a DIE, the DIE is not yet added
to its owner yet, so we don't know whether we should use ref_addr or ref4.
We create a worklist that will be processed during finalization to add
attributes with the correct form (ref_addr or ref4).

We add addDIEEntry to DwarfDebug to be a wrapper around DIE->addValue. It checks
whether we know the correct form, if not, we update the worklist
(DIEEntryWorklist).

A testing case is added to show that we only create a single DIE for a type
MDNode and we use ref_addr to refer to the type DIE.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191792 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 3 insertions, 0 deletions

diff --git a/lib/CodeGen/AsmPrinter/DIE.h b/lib/CodeGen/AsmPrinter/DIE.h
index 6eaa6ee66e..35b76b52c1 100644
--- a/lib/CodeGen/AsmPrinter/DIE.h
+++ b/lib/CodeGen/AsmPrinter/DIE.h
@@ -152,6 +152,9 @@ namespace llvm {
     /// Climb up the parent chain to get the compile unit DIE this DIE belongs
     /// to.
     DIE *getCompileUnit();
+    /// Similar to getCompileUnit, returns null when DIE is not added to an
+    /// owner yet.
+    DIE *checkCompileUnit();
     void setTag(uint16_t Tag) { Abbrev.setTag(Tag); }
     void setOffset(unsigned O) { Offset = O; }
     void setSize(unsigned S) { Size = S; }