[cfe-commits] r43268 - in /cfe/trunk: CodeGen/CodeGenTypes.cpp CodeGen/CodeGenTypes.h test/CodeGen/struct.c

[Chris Lattner]

On Oct 23, 2007, at 4:26 PM, Devang Patel wrote:

> Author: dpatel
> Date: Tue Oct 23 18:26:46 2007
> New Revision: 43268
>
> URL: http://llvm.org/viewvc/llvm-project?rev=43268&view=rev
> Log:
> Handle nested structs.
> typdef struct A { int i; struct A *next; } A

What, no more infinite looping? :)

> ====================================================================== 
> ========
> --- cfe/trunk/CodeGen/CodeGenTypes.cpp (original)
> +++ cfe/trunk/CodeGen/CodeGenTypes.cpp Tue Oct 23 18:26:46 2007
> @@ -167,13 +167,36 @@
>        return ConvertType(cast<EnumDecl>(TD)->getIntegerType());
>      } else if (TD->getKind() == Decl::Struct) {
>        const RecordDecl *RD = cast<const RecordDecl>(TD);
> +
> +      // If this is nested record and this RecordDecl is already  
> under
> +      // process then return associated OpaqueType for now.
> +      llvm::DenseMap<const RecordDecl *, llvm::Type *>::iterator
> +	OpaqueI = RecordTypesToResolve.find(RD);

Tabs tabs tabs, oh my!

Should there be a helper method that does the RecordTypesToResolve  
lookup?  It could return a recorddecl* or null pointer if not in the  
map.

> +      if (OpaqueI != RecordTypesToResolve.end())
> +	return OpaqueI->second;
> +
> +      // Create new OpaqueType now for later use.
> +      llvm::OpaqueType *OpaqueTy =  llvm::OpaqueType::get();
> +      RecordTypesToResolve[RD] = OpaqueTy;

Ah, I see what you mean about needing to always create an opaque  
type.  Yeah, this is fine for now, but please add a "// FIXME: this  
creates a lot of opaque types, most of which are not needed.   
Reevaluate this when we are farther along" or something.

> +      // Layout fields.
>        RecordOrganizer *RO = new RecordOrganizer();
>        for (unsigned i = 0, e = RD->getNumMembers(); i != e; ++i)
>  	RO->addField(RD->getMember(i));
>        RO->layoutFields(*this);
> +
> +      // Get llvm::StructType.
>        RecordLayoutInfo *RLI = new RecordLayoutInfo(RO);
>        ResultType = RLI->getLLVMType();
>        RecordLayouts[ResultType] = RLI;
> +
> +      // Refine any OpaqueType associated with this RecordDecl.
> +      OpaqueTy->refineAbstractTypeTo(ResultType);
> +      OpaqueI = RecordTypesToResolve.find(RD);

This is good in spirit, but needs some changes to actually work.  The  
issue is that resolving types can cause types to merge and fold away,  
causing dangling pointer problems.  We'll have to adopt the llvm- 
types.cpp approach of using a map with PATypeHolder in them.   
PATypeHolder is automatically updated as types are merged.

-Chris