[cfe-commits] r153723 - in /cfe/trunk: lib/CodeGen/CGDecl.cpp lib/CodeGen/ItaniumCXXABI.cpp test/CodeGenCXX/static-init.cpp

[Eli Friedman]

On Thu, Mar 29, 2012 at 9:25 PM, John McCall <rjmccall at apple.com> wrote:
> Author: rjmccall
> Date: Thu Mar 29 23:25:14 2012
> New Revision: 153723
>
> URL: http://llvm.org/viewvc/llvm-project?rev=153723&view=rev
> Log:
> When emitting a static local variable in C++, handle
> the case that the variable already exists.  Partly this is just
> protection against people making crazy declarations with custom
> asm labels or extern "C" names that intentionally collide with
> the manglings of such variables, but the main reason is that we
> can actually emit a static local variable twice with the
> requirement that it match up.  There may be other cases with
> (e.g.) the various nested functions, but the main exemplar is
> with constructor variants, where we can be forced into
> double-emitting the function body under certain circumstances
> like (currently) the presence of virtual bases.
>
> Modified:
>    cfe/trunk/lib/CodeGen/CGDecl.cpp
>    cfe/trunk/lib/CodeGen/ItaniumCXXABI.cpp
>    cfe/trunk/test/CodeGenCXX/static-init.cpp
>
> Modified: cfe/trunk/lib/CodeGen/CGDecl.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGDecl.cpp?rev=153723&r1=153722&r2=153723&view=diff
> ==============================================================================
> --- cfe/trunk/lib/CodeGen/CGDecl.cpp (original)
> +++ cfe/trunk/lib/CodeGen/CGDecl.cpp Thu Mar 29 23:25:14 2012
> @@ -184,6 +184,24 @@
>     Name = GetStaticDeclName(*this, D, Separator);
>
>   llvm::Type *LTy = CGM.getTypes().ConvertTypeForMem(Ty);
> +
> +  // In C++, there are strange possibilities here involving the
> +  // double-emission of constructors and destructors.
> +  if (CGM.getLangOpts().CPlusPlus) {
> +    llvm::GlobalValue *value = CGM.getModule().getNamedValue(Name);
> +    if (value && isa<llvm::GlobalVariable>(value) &&
> +        value->getType() ==
> +          LTy->getPointerTo(CGM.getContext().getTargetAddressSpace(Ty)))
> +      return cast<llvm::GlobalVariable>(value);

This check won't work reliably: the global's type isn't guaranteed to
be the same as the IR type of the variable.

-Eli