Re: [PATCH] sparse, llvm: Fix 'void *' pointer code generation

[Pekka Enberg <penberg@cs.helsinki.fi>]

On Mon, Oct 24, 2011 at 1:43 PM, Pekka Enberg <penberg@kernel.org> wrote:
>> Fix the issue by switching to LLVMIntType(bits_per_pointer) in
>> sym_basetype_type().

On Mon, 24 Oct 2011, Linus Torvalds wrote:
> Why bits_per_pointer? Isn't this the "base type" of void *? A more
> logical choice would seem to be to make it equivalent to "char *", and
> just make it fall through to the "case 8" case?

Indeed. Updated patch below.

 			Pekka

From f90242c21b21d91cfed57aa050b4726b6060dfdd Mon Sep 17 00:00:00 2001
From: Pekka Enberg <penberg@kernel.org>
Date: Mon, 24 Oct 2011 14:11:13 +0300
Subject: [PATCH] sparse, llvm: Fix 'void *' pointer code generation

Sparse front-end generates SYM_PTR with SYM_BASETYPE with bit_size set to -1
for "void *" pointers. We currently map that to LLVMVoidType() but that no
longer works with LLVM Subversion trunk:

   $ ./sparse-llvm validation/backend/struct.c
   sparse-llvm: Type.cpp:676: static llvm::PointerType* llvm::PointerType::get(llvm::Type*, unsigned int): Assertion `isValidElementType(EltTy) && "Invalid type for pointer element!"' failed.
Aborted

Fix the issue by switching to LLVMIntType(bits_per_pointer) in
sym_basetype_type().

Cc: Christopher Li <sparse@chrisli.org>
Cc: Jeff Garzik <jgarzik@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
---
  sparse-llvm.c |    4 +---
  1 files changed, 1 insertions(+), 3 deletions(-)

diff --git a/sparse-llvm.c b/sparse-llvm.c
index a85dfea..fc0c2e9 100644
--- a/sparse-llvm.c
+++ b/sparse-llvm.c
@@ -79,9 +79,7 @@ static LLVMTypeRef sym_basetype_type(struct symbol *sym)
  		}
  	} else {
  		switch (sym->bit_size) {
-		case -1:
-			ret = LLVMVoidType();
-			break;
+		case -1:	/* 'void *' is treated like 'char *' */
  		case 8:
  			ret = LLVMInt8Type();
  			break;
-- 
1.7.6.4