Fix alignment issues in Clang.

Some const-correctness changes snuck in here too, since they were in the
area of code I was modifying.

This seems to make Clang actually work without Bus Error on
32bit-sparc.

Follow-up patches will factor out a trailing-object helper class, to
make classes using the idiom of appending objects to other objects
easier to understand, and to ensure (with static_assert) that required
alignment guarantees continue to hold.

Differential Revision: http://reviews.llvm.org/D10272

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@242554 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 12 insertions, 24 deletions

diff --git a/include/clang/AST/DeclTemplate.h b/include/clang/AST/DeclTemplate.h
index 0fc9b4947d..44b907f749 100644
--- a/include/clang/AST/DeclTemplate.h
+++ b/include/clang/AST/DeclTemplate.h
@@ -43,7 +43,7 @@ typedef llvm::PointerUnion3<TemplateTypeParmDecl*, NonTypeTemplateParmDecl*,
 
 /// \brief Stores a list of template parameters for a TemplateDecl and its
 /// derived classes.
-class TemplateParameterList {
+class LLVM_ALIGNAS(/*alignof(void*)*/ LLVM_PTR_SIZE) TemplateParameterList {
   /// The location of the 'template' keyword.
   SourceLocation TemplateLoc;
 
@@ -542,27 +542,20 @@ public:
 ///     friend void foo<>(T);
 ///   };
 /// \endcode
-class DependentFunctionTemplateSpecializationInfo {
-  struct CA {
-    /// The number of potential template candidates.
-    unsigned NumTemplates;
+class LLVM_ALIGNAS(/*alignof(uint64_t)*/ 8)
+    DependentFunctionTemplateSpecializationInfo {
+  /// The number of potential template candidates.
+  unsigned NumTemplates;
 
-    /// The number of template arguments.
-    unsigned NumArgs;
-  };
-
-  union {
-    // Force sizeof to be a multiple of sizeof(void*) so that the
-    // trailing data is aligned.
-    void *Aligner;
-    struct CA d;
-  };
+  /// The number of template arguments.
+  unsigned NumArgs;
 
   /// The locations of the left and right angle brackets.
   SourceRange AngleLocs;
 
   FunctionTemplateDecl * const *getTemplates() const {
-    return reinterpret_cast<FunctionTemplateDecl*const*>(this+1);
+    return reinterpret_cast<FunctionTemplateDecl *const *>(
+        &getTemplateArgs()[NumArgs]);
   }
 
 public:
@@ -572,9 +565,7 @@ public:
 
   /// \brief Returns the number of function templates that this might
   /// be a specialization of.
-  unsigned getNumTemplates() const {
-    return d.NumTemplates;
-  }
+  unsigned getNumTemplates() const { return NumTemplates; }
 
   /// \brief Returns the i'th template candidate.
   FunctionTemplateDecl *getTemplate(unsigned I) const {
@@ -584,14 +575,11 @@ public:
 
   /// \brief Returns the explicit template arguments that were given.
   const TemplateArgumentLoc *getTemplateArgs() const {
-    return reinterpret_cast<const TemplateArgumentLoc*>(
-                                            &getTemplates()[getNumTemplates()]);
+    return reinterpret_cast<const TemplateArgumentLoc *>(this + 1);
   }
 
   /// \brief Returns the number of explicit template arguments that were given.
-  unsigned getNumTemplateArgs() const {
-    return d.NumArgs;
-  }
+  unsigned getNumTemplateArgs() const { return NumArgs; }
 
   /// \brief Returns the nth template argument.
   const TemplateArgumentLoc &getTemplateArg(unsigned I) const {