Fixup debug information for the location information for __block

variables.  For this to work, the backend needs to handle more complex
forms for locations.

A typical utterance would be:

        %forwarding = getelementptr %0* %use_by_ref, i32 0, i32 1               ; <i8**> [#uses=1]
        %0 = load i8** %forwarding              ; <i8*> [#uses=1]
        %1 = bitcast i8* %0 to %0*              ; <%0*> [#uses=1]
        %x = getelementptr %0* %1, i32 0, i32 4         ; <i32*> [#uses=1]
        %2 = bitcast i32* %x to { }*            ; <{ }*> [#uses=1]
        call void @llvm.dbg.declare({ }* %2, { }* bitcast (%llvm.dbg.variable.type* @llvm.dbg.variable to { }*))

Presently when selection finds something it doesn't understand, it
just avoids generating any information, which is safe, just
incomplete.  Radar 6867696


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@71824 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 4 insertions, 2 deletions

diff --git a/lib/CodeGen/CGDecl.cpp b/lib/CodeGen/CGDecl.cpp
index b6efcffdfc..9de722e19d 100644
--- a/lib/CodeGen/CGDecl.cpp
+++ b/lib/CodeGen/CGDecl.cpp
@@ -315,8 +315,10 @@ void CodeGenFunction::EmitLocalBlockVarDecl(const VarDecl &D) {
     if (isByRef) {
       llvm::Value *Loc;
       bool needsCopyDispose = BlockRequiresCopying(Ty);
-      // FIXME: I think we need to indirect through the forwarding pointer first
-      Loc = Builder.CreateStructGEP(DeclPtr, needsCopyDispose*2+4, "x");
+      Loc = Builder.CreateStructGEP(DeclPtr, 1, "forwarding");
+      Loc = Builder.CreateLoad(Loc, false);
+      Loc = Builder.CreateBitCast(Loc, DeclPtr->getType());
+      Loc = Builder.CreateStructGEP(Loc, needsCopyDispose*2+4, "x");
       DI->EmitDeclareOfAutoVariable(&D, Loc, Builder);
     } else
       DI->EmitDeclareOfAutoVariable(&D, DeclPtr, Builder);