Code generation support for C99 designated initializers.

The approach I've taken in this patch is relatively straightforward,
although the code itself is non-trivial. Essentially, as we process
an initializer list we build up a fully-explicit representation of the
initializer list, where each of the subobject initializations occurs
in order. Designators serve to "fill in" subobject initializations in
a non-linear way. The fully-explicit representation makes initializer
lists (both with and without designators) easy to grok for codegen and
later semantic analyses. We keep the syntactic form of the initializer
list linked into the AST for those clients interested in exactly what
the user wrote.

Known limitations:
  - Designating a member of a union that isn't the first member may
    result in bogus initialization (we warn about this)
  - GNU array-range designators are not supported (we warn about this)

llvm-svn: 63242

1 files changed, 40 insertions, 10 deletions

diff --git a/clang/lib/Sema/Sema.h b/clang/lib/Sema/Sema.h
index d017e6f9c7b..8cf10ff3e2a 100644
--- a/clang/lib/Sema/Sema.h
+++ b/clang/lib/Sema/Sema.h
@@ -28,6 +28,7 @@
 #include "llvm/ADT/OwningPtr.h"
 #include <string>
 #include <vector>
+#include <map>
 
 namespace llvm {
   class APSInt;
@@ -1835,38 +1836,67 @@ private:
 class InitListChecker {
   Sema *SemaRef;
   bool hadError;
+  std::map<InitListExpr *, InitListExpr *> SyntacticToSemantic;
+  InitListExpr *FullyStructuredList;
   
   void CheckImplicitInitList(InitListExpr *ParentIList, QualType T, 
-                             unsigned &Index);
+                             unsigned &Index, InitListExpr *StructuredInitList,
+                             unsigned &StructuredInitIndex);
   void CheckExplicitInitList(InitListExpr *IList, QualType &T,
-                             unsigned &Index);
-
+                             unsigned &Index, InitListExpr *StructuredInitList,
+                             unsigned &StructuredInitIndex);
   void CheckListElementTypes(InitListExpr *IList, QualType &DeclType, 
                              bool SubobjectIsDesignatorContext, 
-                             unsigned &Index);
+                             unsigned &Index,
+                             InitListExpr *StructuredInitList,
+                             unsigned &StructuredInitIndex);
   void CheckSubElementType(InitListExpr *IList, QualType ElemType, 
-                           Expr *expr, unsigned &Index);
+                           Expr *expr, unsigned &Index,
+                           InitListExpr *StructuredInitList,
+                           unsigned &StructuredInitIndex);
   // FIXME: Does DeclType need to be a reference type?
   void CheckScalarType(InitListExpr *IList, QualType &DeclType, 
-                       Expr *expr, unsigned &Index);
-  void CheckVectorType(InitListExpr *IList, QualType DeclType, unsigned &Index);
+                       Expr *expr, unsigned &Index,
+                       InitListExpr *StructuredInitList,
+                       unsigned &StructuredInitIndex);
+  void CheckVectorType(InitListExpr *IList, QualType DeclType, unsigned &Index,
+                       InitListExpr *StructuredInitList,
+                       unsigned &StructuredInitIndex);
   void CheckStructUnionTypes(InitListExpr *IList, QualType DeclType, 
                              RecordDecl::field_iterator Field, 
-                             bool SubobjectIsDesignatorContext, unsigned &Index);
+                             bool SubobjectIsDesignatorContext, unsigned &Index,
+                             InitListExpr *StructuredInitList,
+                             unsigned &StructuredInitIndex);
   void CheckArrayType(InitListExpr *IList, QualType &DeclType, 
                       llvm::APSInt elementIndex, 
-                      bool SubobjectIsDesignatorContext, unsigned &Index);
+                      bool SubobjectIsDesignatorContext, unsigned &Index,
+                      InitListExpr *StructuredInitList,
+                      unsigned &StructuredInitIndex);
   bool CheckDesignatedInitializer(InitListExpr *IList, DesignatedInitExpr *DIE, 
                                   DesignatedInitExpr::designators_iterator D,
                                   QualType &CurrentObjectType, 
                                   RecordDecl::field_iterator *NextField,
                                   llvm::APSInt *NextElementIndex,
-                                  unsigned &Index);
+                                  unsigned &Index,
+                                  InitListExpr *StructuredList,
+                                  unsigned &StructuredIndex);
+  InitListExpr *getStructuredSubobjectInit(InitListExpr *IList, unsigned Index,
+                                           QualType CurrentObjectType,
+                                           InitListExpr *StructuredList,
+                                           unsigned StructuredIndex,
+                                           SourceRange InitRange);
+  void UpdateStructuredListElement(InitListExpr *StructuredInitList,
+                                   unsigned &StructuredInitIndex,
+                                   Expr *expr);
   int numArrayElements(QualType DeclType);
   int numStructUnionElements(QualType DeclType);
 public:
   InitListChecker(Sema *S, InitListExpr *IL, QualType &T);
   bool HadError() { return hadError; }
+
+  // @brief Retrieves the fully-structured initializer list used for
+  // semantic analysis and code generation.
+  InitListExpr *getFullyStructuredList() const { return FullyStructuredList; }
 };
 
 /// BlockSemaInfo - When a block is being parsed, this contains information