Remove mutable data on TagType and InjectedClassNameType, by instead walking the declaration chain in search of a definition. This is necessary for a sane chained PCH implementation. No observable performance change on Carbon.h syntax-only, and bootstraps cleanly.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@110051 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 26 insertions, 20 deletions

diff --git a/lib/AST/Decl.cpp b/lib/AST/Decl.cpp
index a30a430382..0e0bbf34a1 100644
--- a/lib/AST/Decl.cpp
+++ b/lib/AST/Decl.cpp
@@ -1534,14 +1534,7 @@ void TagDecl::setTypedefForAnonDecl(TypedefDecl *TDD) {
 }
 
 void TagDecl::startDefinition() {
-  if (TagType *TagT = const_cast<TagType *>(TypeForDecl->getAs<TagType>())) {
-    TagT->decl.setPointer(this);
-    TagT->decl.setInt(1);
-  } else if (InjectedClassNameType *Injected
-               = const_cast<InjectedClassNameType *>(
-                                 TypeForDecl->getAs<InjectedClassNameType>())) {
-    Injected->Decl = cast<CXXRecordDecl>(this);
-  }
+  IsBeingDefined = true;
 
   if (isa<CXXRecordDecl>(this)) {
     CXXRecordDecl *D = cast<CXXRecordDecl>(this);
@@ -1558,17 +1551,7 @@ void TagDecl::completeDefinition() {
          "definition completed but not started");
 
   IsDefinition = true;
-  if (TagType *TagT = const_cast<TagType *>(TypeForDecl->getAs<TagType>())) {
-    assert(TagT->decl.getPointer() == this &&
-           "Attempt to redefine a tag definition?");
-    TagT->decl.setInt(0);
-  } else if (InjectedClassNameType *Injected
-               = const_cast<InjectedClassNameType *>(
-                                TypeForDecl->getAs<InjectedClassNameType>())) {
-    assert(Injected->Decl == this &&
-           "Attempt to redefine a class template definition?");
-    (void)Injected;
-  }
+  IsBeingDefined = false;
 }
 
 TagDecl* TagDecl::getDefinition() const {
diff --git a/lib/AST/Type.cpp b/lib/AST/Type.cpp
index 49d579f4a0..1085efec19 100644
--- a/lib/AST/Type.cpp
+++ b/lib/AST/Type.cpp
@@ -1072,7 +1072,30 @@ void DependentDecltypeType::Profile(llvm::FoldingSetNodeID &ID,
 
 TagType::TagType(TypeClass TC, const TagDecl *D, QualType can)
   : Type(TC, can, D->isDependentType()),
-    decl(const_cast<TagDecl*>(D), 0) {}
+    decl(const_cast<TagDecl*>(D)) {}
+
+static TagDecl *getInterestingTagDecl(TagDecl *decl) {
+  for (TagDecl::redecl_iterator I = decl->redecls_begin(),
+                                E = decl->redecls_end();
+       I != E; ++I) {
+    if (I->isDefinition() || I->isBeingDefined())
+      return *I;
+  }
+  // If there's no definition (not even in progress), return what we have.
+  return decl;
+}
+
+TagDecl *TagType::getDecl() const {
+  return getInterestingTagDecl(decl);
+}
+
+bool TagType::isBeingDefined() const {
+  return getDecl()->isBeingDefined();
+}
+
+CXXRecordDecl *InjectedClassNameType::getDecl() const {
+  return cast<CXXRecordDecl>(getInterestingTagDecl(Decl));
+}
 
 bool RecordType::classof(const TagType *TT) {
   return isa<RecordDecl>(TT->getDecl());