[DebugInfo] [DWARFv5] Unique abbrevs for DIEs with different implicit_const values

Take DW_FORM_implicit_const attribute value into account when profiling
DIEAbbrevData.

Currently if we have two similar types with implicit_const attributes and
different values we end up with only one abbrev in .debug_abbrev section.
For example consider two structures: S1 with implicit_const attribute ATTR
and value VAL1 and S2 with implicit_const ATTR and value VAL2.
The .debug_abbrev section will contain only 1 related record:

[N] DW_TAG_structure_type       DW_CHILDREN_yes
        DW_AT_ATTR        DW_FORM_implicit_const  VAL1
        // ....

This is incorrect as struct S2 (with VAL2) will use abbrev record with VAL1.

With this patch we will have two different abbreviations here:

[N] DW_TAG_structure_type       DW_CHILDREN_yes
        DW_AT_ATTR        DW_FORM_implicit_const  VAL1
        // ....

[M] DW_TAG_structure_type       DW_CHILDREN_yes
        DW_AT_ATTR        DW_FORM_implicit_const  VAL2
        // ....

llvm-svn: 296691

1 files changed, 8 insertions, 2 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/DIE.cpp b/llvm/lib/CodeGen/AsmPrinter/DIE.cpp
index bb008ec557f..dd8a839635c 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DIE.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DIE.cpp
@@ -42,6 +42,8 @@ void DIEAbbrevData::Profile(FoldingSetNodeID &ID) const {
   // overloads.  Otherwise MSVC 2010 thinks this call is ambiguous.
   ID.AddInteger(unsigned(Attribute));
   ID.AddInteger(unsigned(Form));
+  if (Form == dwarf::DW_FORM_implicit_const)
+    ID.AddInteger(Value);
 }
 
 //===----------------------------------------------------------------------===//
@@ -107,8 +109,12 @@ void DIEAbbrev::print(raw_ostream &O) {
     O << "  "
       << dwarf::AttributeString(Data[i].getAttribute())
       << "  "
-      << dwarf::FormEncodingString(Data[i].getForm())
-      << '\n';
+      << dwarf::FormEncodingString(Data[i].getForm());
+
+    if (Data[i].getForm() == dwarf::DW_FORM_implicit_const)
+      O << " " << Data[i].getValue();
+
+    O << '\n';
   }
 }