DIEHash: Support for simple (non-recursive, non-reused) type references

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192924 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/AsmPrinter/DIEHash.cpp

@@ -274,6 +274,9 @@ void DIEHash::collectAttributes(DIE *Die, DIEAttrs &Attrs) {
     case dwarf::DW_AT_vtable_elem_location:
       COLLECT_ATTR(DW_AT_vtable_elem_location)
       break;
+    case dwarf::DW_AT_type:
+      COLLECT_ATTR(DW_AT_type)
+      break;
     default:
       break;
     }
@@ -286,19 +289,39 @@ void DIEHash::hashAttribute(AttrEntry Attr) {
   const DIEValue *Value = Attr.Val;
   const DIEAbbrevData *Desc = Attr.Desc;
 
-  // TODO: Add support for types.
+  // 7.27s3
+  // ... An attribute that refers to another type entry T is processed as
+  // follows:
+  // a) If T is in the list of [previously hashed types], use the letter 'R' as
+  // the marker and use the unsigned LEB128 encoding of [the index of T in the
+  // list] as the attribute value; otherwise,
 
-  // Add the letter A to the hash.
+  // [TODO: implement clause (a)]
+
+  if (const DIEEntry *EntryAttr = dyn_cast<DIEEntry>(Value)) {
+    DIE *Entry = EntryAttr->getEntry();
+
+    // b) use the letter 'T' as a the marker, ...
+    addULEB128('T');
+
+    addULEB128(Desc->getAttribute());
+
+    // ... process the type T recursively by performing Steps 2 through 7, and
+    // use the result as the attribute value.
+    computeHash(Entry);
+    return;
+  }
+
+  // Other attribute values use the letter 'A' as the marker, ...
   addULEB128('A');
 
-  // Then the attribute code.
   addULEB128(Desc->getAttribute());
 
-  // To ensure reproducibility of the signature, the set of forms used in the
+  // ... and the value consists of the form code (encoded as an unsigned LEB128
+  // value) followed by the encoding of the value according to the form code. To
+  // ensure reproducibility of the signature, the set of forms used in the
   // signature computation is limited to the following: DW_FORM_sdata,
   // DW_FORM_flag, DW_FORM_string, and DW_FORM_block.
-
-  // TODO: Add support for additional forms.
   switch (Desc->getForm()) {
   case dwarf::DW_FORM_string:
     llvm_unreachable(
@@ -315,6 +338,7 @@ void DIEHash::hashAttribute(AttrEntry Attr) {
     addULEB128(dwarf::DW_FORM_sdata);
     addSLEB128((int64_t)cast<DIEInteger>(Value)->getValue());
     break;
+  // TODO: Add support for additional forms.
   }
 }
 
@@ -375,6 +399,7 @@ void DIEHash::hashAttributes(const DIEAttrs &Attrs) {
   ADD_ATTR(Attrs.DW_AT_virtuality);
   ADD_ATTR(Attrs.DW_AT_visibility);
   ADD_ATTR(Attrs.DW_AT_vtable_elem_location);
+  ADD_ATTR(Attrs.DW_AT_type);
 
   // FIXME: Add the extended attributes.
 }

lib/CodeGen/AsmPrinter/DIEHash.h

@@ -76,6 +76,7 @@ class DIEHash {
     AttrEntry DW_AT_virtuality;
     AttrEntry DW_AT_visibility;
     AttrEntry DW_AT_vtable_elem_location;
+    AttrEntry DW_AT_type;
 
     // Insert any additional ones here...
   };

unittests/CodeGen/DIEHashTest.cpp

@@ -51,9 +51,6 @@ TEST(NamedType, DIEHash) {
   Foo.addValue(dwarf::DW_AT_name, dwarf::DW_FORM_strp, &FooStr);
   Foo.addValue(dwarf::DW_AT_byte_size, dwarf::DW_FORM_data1, &One);
 
-  // Line and file number are ignored.
-  Foo.addValue(dwarf::DW_AT_decl_file, dwarf::DW_FORM_data1, &One);
-  Foo.addValue(dwarf::DW_AT_decl_line, dwarf::DW_FORM_data1, &One);
   uint64_t MD5Res = DIEHash().computeTypeSignature(&Foo);
 
   // The exact same hash GCC produces for this DIE.
@@ -78,10 +75,6 @@ TEST(NamespacedType, DIEHash) {
   Foo->addValue(dwarf::DW_AT_name, dwarf::DW_FORM_strp, &FooStr);
   Foo->addValue(dwarf::DW_AT_byte_size, dwarf::DW_FORM_data1, &One);
 
-  // Line and file number are ignored.
-  Foo->addValue(dwarf::DW_AT_decl_file, dwarf::DW_FORM_data1, &One);
-  Foo->addValue(dwarf::DW_AT_decl_line, dwarf::DW_FORM_data1, &One);
-
   Space->addChild(Foo);
   CU.addChild(Space);
 
@@ -90,4 +83,33 @@ TEST(NamespacedType, DIEHash) {
   // The exact same hash GCC produces for this DIE.
   ASSERT_EQ(0x7b80381fd17f1e33ULL, MD5Res);
 }
+
+TEST(TypeWithMember, DIEHash) {
+  DIE Unnamed(dwarf::DW_TAG_structure_type);
+  DIEInteger Four(4);
+  Unnamed.addValue(dwarf::DW_AT_byte_size, dwarf::DW_FORM_data1, &Four);
+
+  DIE *Member = new DIE(dwarf::DW_TAG_member);
+  DIEString MemberStr(&Four, "member");
+  Member->addValue(dwarf::DW_AT_name, dwarf::DW_FORM_strp, &MemberStr);
+  // type
+  DIEInteger Zero(0);
+  Member->addValue(dwarf::DW_AT_data_member_location, dwarf::DW_FORM_data1, &Zero);
+
+  Unnamed.addChild(Member);
+
+  DIE Int(dwarf::DW_TAG_base_type);
+  DIEString IntStr(&Four, "int");
+  Int.addValue(dwarf::DW_AT_name, dwarf::DW_FORM_strp, &IntStr);
+  Int.addValue(dwarf::DW_AT_byte_size, dwarf::DW_FORM_data1, &Four);
+  DIEInteger Five(5);
+  Int.addValue(dwarf::DW_AT_encoding, dwarf::DW_FORM_data1, &Five);
+
+  DIEEntry IntRef(&Int);
+  Member->addValue(dwarf::DW_AT_type, dwarf::DW_FORM_ref4, &IntRef);
+
+  uint64_t MD5Res = DIEHash().computeTypeSignature(&Unnamed);
+
+  ASSERT_EQ(0x5646aa436b7e07c6ULL, MD5Res);
+}
 }