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)



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@63242 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 2 insertions, 6 deletions

diff --git a/lib/CodeGen/CGExprConstant.cpp b/lib/CodeGen/CGExprConstant.cpp
index 32d126e590..3b6ebb4d56 100644
--- a/lib/CodeGen/CGExprConstant.cpp
+++ b/lib/CodeGen/CGExprConstant.cpp
@@ -242,6 +242,8 @@ public:
     const llvm::Type *Ty = ConvertType(ILE->getType());
 
     // Find the field decl we're initializing, if any
+    // FIXME: C99 designated initializers won't always initialize the 
+    // first field
     int FieldNo = 0; // Field no in RecordDecl
     FieldDecl* curField = 0;
     for (RecordDecl::field_iterator Field = RD->field_begin(),
@@ -304,12 +306,6 @@ public:
       return llvm::Constant::getNullValue(RetTy);
     }
     
-    // FIXME: We don't codegen or sema designators yet.
-    if (ILE->hadDesignators()) {
-      CGM.ErrorUnsupported(ILE, "initializer list with designators");
-      return llvm::UndefValue::get(ConvertType(ILE->getType()));
-    }
-
     if (ILE->getType()->isArrayType())
       return EmitArrayInitialization(ILE);