From: Justin Bogner <mail@justinbogner.com>
Date: Fri, 10 Jul 2015 23:05:47 +0000 (+0000)
Subject: Sema: Allow null names to be passed in to isAcceptableTagRedeclaration
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=2290c8daa21d10957df9cefd59e7ac2cd71dc2c8;p=clang

Sema: Allow null names to be passed in to isAcceptableTagRedeclaration

It's possible for TagRedeclarations to involve decls without a name,
ie, anonymous enums. We hit some undefined behaviour if we bind these
null names to the reference here.

We never dereference the name, so it's harmless if it's null - make it
a pointer to allow that.

Fixes the Modules/submodules-merge-defs.cpp test under ubsan.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@241963 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/include/clang/Sema/Sema.h b/include/clang/Sema/Sema.h
index b5a1b0be7c..ca06b214da 100644
--- a/include/clang/Sema/Sema.h
+++ b/include/clang/Sema/Sema.h
@@ -1849,7 +1849,7 @@ public:
   bool isAcceptableTagRedeclaration(const TagDecl *Previous,
                                     TagTypeKind NewTag, bool isDefinition,
                                     SourceLocation NewTagLoc,
-                                    const IdentifierInfo &Name);
+                                    const IdentifierInfo *Name);
 
   enum TagUseKind {
     TUK_Reference,   // Reference to a tag:  'struct foo *X;'
diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index 9db14bf70e..28877210c6 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -11294,7 +11294,7 @@ static bool isClassCompatTagKind(TagTypeKind Tag)
 bool Sema::isAcceptableTagRedeclaration(const TagDecl *Previous,
                                         TagTypeKind NewTag, bool isDefinition,
                                         SourceLocation NewTagLoc,
-                                        const IdentifierInfo &Name) {
+                                        const IdentifierInfo *Name) {
   // C++ [dcl.type.elab]p3:
   //   The class-key or enum keyword present in the
   //   elaborated-type-specifier shall agree in kind with the
@@ -11323,7 +11323,7 @@ bool Sema::isAcceptableTagRedeclaration(const TagDecl *Previous,
       // In a template instantiation, do not offer fix-its for tag mismatches
       // since they usually mess up the template instead of fixing the problem.
       Diag(NewTagLoc, diag::warn_struct_class_tag_mismatch)
-        << getRedeclDiagFromTagKind(NewTag) << isTemplate << &Name
+        << getRedeclDiagFromTagKind(NewTag) << isTemplate << Name
         << getRedeclDiagFromTagKind(OldTag);
       return true;
     }
@@ -11342,7 +11342,7 @@ bool Sema::isAcceptableTagRedeclaration(const TagDecl *Previous,
           if (!previousMismatch) {
             previousMismatch = true;
             Diag(NewTagLoc, diag::warn_struct_class_previous_tag_mismatch)
-              << getRedeclDiagFromTagKind(NewTag) << isTemplate << &Name
+              << getRedeclDiagFromTagKind(NewTag) << isTemplate << Name
               << getRedeclDiagFromTagKind(I->getTagKind());
           }
           Diag(I->getInnerLocStart(), diag::note_struct_class_suggestion)
@@ -11364,7 +11364,7 @@ bool Sema::isAcceptableTagRedeclaration(const TagDecl *Previous,
     }
 
     Diag(NewTagLoc, diag::warn_struct_class_tag_mismatch)
-      << getRedeclDiagFromTagKind(NewTag) << isTemplate << &Name
+      << getRedeclDiagFromTagKind(NewTag) << isTemplate << Name
       << getRedeclDiagFromTagKind(OldTag);
     Diag(Redecl->getLocation(), diag::note_previous_use);
 
@@ -11847,7 +11847,7 @@ Decl *Sema::ActOnTag(Scope *S, unsigned TagSpec, TagUseKind TUK,
         // struct or something similar.
         if (!isAcceptableTagRedeclaration(PrevTagDecl, Kind,
                                           TUK == TUK_Definition, KWLoc,
-                                          *Name)) {
+                                          Name)) {
           bool SafeToContinue
             = (PrevTagDecl->getTagKind() != TTK_Enum &&
                Kind != TTK_Enum);
diff --git a/lib/Sema/SemaTemplate.cpp b/lib/Sema/SemaTemplate.cpp
index 97904ce599..035c37cfe6 100644
--- a/lib/Sema/SemaTemplate.cpp
+++ b/lib/Sema/SemaTemplate.cpp
@@ -1008,7 +1008,7 @@ Sema::CheckClassTemplate(Scope *S, unsigned TagSpec, TagUseKind TUK,
     //   template declaration (7.1.5.3).
     RecordDecl *PrevRecordDecl = PrevClassTemplate->getTemplatedDecl();
     if (!isAcceptableTagRedeclaration(PrevRecordDecl, Kind,
-                                      TUK == TUK_Definition,  KWLoc, *Name)) {
+                                      TUK == TUK_Definition,  KWLoc, Name)) {
       Diag(KWLoc, diag::err_use_with_wrong_tag)
         << Name
         << FixItHint::CreateReplacement(KWLoc, PrevRecordDecl->getKindName());
@@ -2310,7 +2310,7 @@ TypeResult Sema::ActOnTagTemplateIdType(TagUseKind TUK,
     assert(Id && "templated class must have an identifier");
     
     if (!isAcceptableTagRedeclaration(D, TagKind, TUK == TUK_Definition,
-                                      TagLoc, *Id)) {
+                                      TagLoc, Id)) {
       Diag(TagLoc, diag::err_use_with_wrong_tag)
         << Result
         << FixItHint::CreateReplacement(SourceRange(TagLoc), D->getKindName());
@@ -6199,7 +6199,7 @@ Sema::ActOnClassTemplateSpecialization(Scope *S, unsigned TagSpec,
   assert(Kind != TTK_Enum && "Invalid enum tag in class template spec!");
   if (!isAcceptableTagRedeclaration(ClassTemplate->getTemplatedDecl(),
                                     Kind, TUK == TUK_Definition, KWLoc,
-                                    *ClassTemplate->getIdentifier())) {
+                                    ClassTemplate->getIdentifier())) {
     Diag(KWLoc, diag::err_use_with_wrong_tag)
       << ClassTemplate
       << FixItHint::CreateReplacement(KWLoc,
@@ -7235,7 +7235,7 @@ Sema::ActOnExplicitInstantiation(Scope *S,
 
   if (!isAcceptableTagRedeclaration(ClassTemplate->getTemplatedDecl(),
                                     Kind, /*isDefinition*/false, KWLoc,
-                                    *ClassTemplate->getIdentifier())) {
+                                    ClassTemplate->getIdentifier())) {
     Diag(KWLoc, diag::err_use_with_wrong_tag)
       << ClassTemplate
       << FixItHint::CreateReplacement(KWLoc,
diff --git a/lib/Sema/SemaTemplateInstantiate.cpp b/lib/Sema/SemaTemplateInstantiate.cpp
index 7d58017a9b..c1961e516d 100644
--- a/lib/Sema/SemaTemplateInstantiate.cpp
+++ b/lib/Sema/SemaTemplateInstantiate.cpp
@@ -989,7 +989,7 @@ TemplateInstantiator::RebuildElaboratedType(SourceLocation KeywordLoc,
     if (Id && Keyword != ETK_None && Keyword != ETK_Typename) {
       TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForKeyword(Keyword);
       if (!SemaRef.isAcceptableTagRedeclaration(TD, Kind, /*isDefinition*/false,
-                                                TagLocation, *Id)) {
+                                                TagLocation, Id)) {
         SemaRef.Diag(TagLocation, diag::err_use_with_wrong_tag)
           << Id
           << FixItHint::CreateReplacement(SourceRange(TagLocation),
diff --git a/lib/Sema/TreeTransform.h b/lib/Sema/TreeTransform.h
index 8b150c3a65..6e193a3529 100644
--- a/lib/Sema/TreeTransform.h
+++ b/lib/Sema/TreeTransform.h
@@ -1010,7 +1010,7 @@ public:
     }
 
     if (!SemaRef.isAcceptableTagRedeclaration(Tag, Kind, /*isDefinition*/false,
-                                              IdLoc, *Id)) {
+                                              IdLoc, Id)) {
       SemaRef.Diag(KeywordLoc, diag::err_use_with_wrong_tag) << Id;
       SemaRef.Diag(Tag->getLocation(), diag::note_previous_use);
       return QualType();