3 files changed, 36 insertions, 10 deletions

diff --git a/llvm/include/llvm/CodeGen/DIE.h b/llvm/include/llvm/CodeGen/DIE.h
index 09c3bf6a1b5..95c4b4248bb 100644
--- a/llvm/include/llvm/CodeGen/DIE.h
+++ b/llvm/include/llvm/CodeGen/DIE.h
@@ -52,13 +52,20 @@ class DIEAbbrevData {
   /// Dwarf form code.
   dwarf::Form Form;
 
+  /// Dwarf attribute value for DW_FORM_implicit_const
+  int64_t Value;
+
 public:
-  DIEAbbrevData(dwarf::Attribute A, dwarf::Form F) : Attribute(A), Form(F) {}
+  DIEAbbrevData(dwarf::Attribute A, dwarf::Form F)
+      : Attribute(A), Form(F), Value(0) {}
+  DIEAbbrevData(dwarf::Attribute A, int64_t V)
+      : Attribute(A), Form(dwarf::DW_FORM_implicit_const), Value(V) {}
 
   /// Accessors.
   /// @{
   dwarf::Attribute getAttribute() const { return Attribute; }
   dwarf::Form getForm() const { return Form; }
+  int64_t getValue() const { return Value; }
   /// @}
 
   /// Used to gather unique data for the abbreviation folding set.
@@ -102,6 +109,11 @@ public:
     Data.push_back(DIEAbbrevData(Attribute, Form));
   }
 
+  /// Adds attribute with DW_FORM_implicit_const value
+  void AddImplicitConstAttribute(dwarf::Attribute Attribute, int64_t Value) {
+    Data.push_back(DIEAbbrevData(Attribute, Value));
+  }
+
   /// Used to gather unique data for the abbreviation folding set.
   void Profile(FoldingSetNodeID &ID) const;
 
diff --git a/llvm/include/llvm/DebugInfo/DWARF/DWARFAbbreviationDeclaration.h b/llvm/include/llvm/DebugInfo/DWARF/DWARFAbbreviationDeclaration.h
index 778817f57bf..db9bd506be8 100644
--- a/llvm/include/llvm/DebugInfo/DWARF/DWARFAbbreviationDeclaration.h
+++ b/llvm/include/llvm/DebugInfo/DWARF/DWARFAbbreviationDeclaration.h
@@ -23,21 +23,32 @@ class raw_ostream;
 class DWARFAbbreviationDeclaration {
 public:
   struct AttributeSpec {
-    AttributeSpec(dwarf::Attribute A, dwarf::Form F, Optional<uint8_t> S)
-        : Attr(A), Form(F), ByteSize(S) {}
+    AttributeSpec(dwarf::Attribute A, dwarf::Form F, Optional<int64_t> V)
+        : Attr(A), Form(F), ByteSizeOrValue(V) {}
     dwarf::Attribute Attr;
     dwarf::Form Form;
-    /// If ByteSize has a value, then it contains the fixed size in bytes for
-    /// the Form in this object. If ByteSize doesn't have a value, then the
-    /// byte size of Form either varies according to the DWARFUnit that it is
-    /// contained in or the value size varies and must be decoded from the
-    /// debug information in order to determine its size.
-    Optional<uint8_t> ByteSize;
+    /// The following field is used for ByteSize for non-implicit_const
+    /// attributes and as value for implicit_const ones, indicated by
+    /// Form == DW_FORM_implicit_const.
+    /// The following cases are distinguished:
+    /// * Form != DW_FORM_implicit_const and ByteSizeOrValue has a value:
+    ///     ByteSizeOrValue contains the fixed size in bytes
+    ///     for the Form in this object.
+    /// * Form != DW_FORM_implicit_const and ByteSizeOrValue is None:
+    ///     byte size of Form either varies according to the DWARFUnit
+    ///     that it is contained in or the value size varies and must be
+    ///     decoded from the debug information in order to determine its size.
+    /// * Form == DW_FORM_implicit_const:
+    ///     ByteSizeOrValue contains value for the implicit_const attribute.
+    Optional<int64_t> ByteSizeOrValue;
+    bool isImplicitConst() const {
+      return Form == dwarf::DW_FORM_implicit_const;
+    }
     /// Get the fixed byte size of this Form if possible. This function might
     /// use the DWARFUnit to calculate the size of the Form, like for
     /// DW_AT_address and DW_AT_ref_addr, so this isn't just an accessor for
     /// the ByteSize member.
-    Optional<uint8_t> getByteSize(const DWARFUnit &U) const;
+    Optional<int64_t> getByteSize(const DWARFUnit &U) const;
   };
   typedef SmallVector<AttributeSpec, 8> AttributeSpecVector;
 
diff --git a/llvm/include/llvm/DebugInfo/DWARF/DWARFFormValue.h b/llvm/include/llvm/DebugInfo/DWARF/DWARFFormValue.h
index 920880cea10..1b7659dfb04 100644
--- a/llvm/include/llvm/DebugInfo/DWARF/DWARFFormValue.h
+++ b/llvm/include/llvm/DebugInfo/DWARF/DWARFFormValue.h
@@ -57,6 +57,9 @@ public:
   DWARFFormValue(dwarf::Form F = dwarf::Form(0)) : Form(F), U(nullptr) {}
   dwarf::Form getForm() const { return Form; }
   void setForm(dwarf::Form F) { Form = F; }
+  void setUValue(uint64_t V) { Value.uval = V; }
+  void setSValue(int64_t V) { Value.sval = V; }
+  void setPValue(const char *V) { Value.cstr = V; }
   bool isFormClass(FormClass FC) const;
   const DWARFUnit *getUnit() const { return U; }
   void dump(raw_ostream &OS) const;