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

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

[Pekka Enberg]

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 |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/sparse-llvm.c b/sparse-llvm.c
index a85dfea..ec46a04 100644
--- a/sparse-llvm.c
+++ b/sparse-llvm.c
@@ -80,7 +80,7 @@ static LLVMTypeRef sym_basetype_type(struct symbol *sym)
 	} else {
 		switch (sym->bit_size) {
 		case -1:
-			ret = LLVMVoidType();
+			ret = LLVMIntType(bits_in_pointer);
 			break;
 		case 8:
 			ret = LLVMInt8Type();
-- 
1.7.6.4

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

[Linus Torvalds]

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().

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?

       Linus

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

[Pekka Enberg]

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

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

[Jonathan Neuschäfer]

On Mon, Oct 24, 2011 at 02:56:41PM +0300, Pekka Enberg wrote:
> Fix the issue by switching to LLVMIntType(bits_per_pointer) in
> sym_basetype_type().

You didn't update the commit message.

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

[Pekka Enberg]

[-- Attachment #1: Type: TEXT/PLAIN, Size: 1939 bytes --]

> On Mon, Oct 24, 2011 at 02:56:41PM +0300, Pekka Enberg wrote:
>> Fix the issue by switching to LLVMIntType(bits_per_pointer) in
>> sym_basetype_type().

On Mon, 24 Oct 2011, Jonathan Neuschäfer wrote:
> You didn't update the commit message.

Thanks for pointing that out. Jeff, does this look OK?

 			Pekka

From e6981551345b7284f6995556398b3564d02afc42 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 treating 'void *' as 'char *' as suggested by Linus:

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?

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

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

[Jeff Garzik]

On 10/24/2011 08:33 AM, Pekka Enberg wrote:
>> On Mon, Oct 24, 2011 at 02:56:41PM +0300, Pekka Enberg wrote:
>>> Fix the issue by switching to LLVMIntType(bits_per_pointer) in
>>> sym_basetype_type().
>
> On Mon, 24 Oct 2011, Jonathan Neuschäfer wrote:
>> You didn't update the commit message.
>
> Thanks for pointing that out. Jeff, does this look OK?

I don't know what bit_size==-1 means off the top of my head, so I assume 
yes ;-)

	Jeff




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

[Pekka Enberg]

On Mon, Oct 24, 2011 at 6:13 PM, Jeff Garzik <jeff@garzik.org> wrote:
>> Thanks for pointing that out. Jeff, does this look OK?
>
> I don't know what bit_size==-1 means off the top of my head, so I assume yes

So

  void *p;

looks as follows with test-inspect:

  0: SYM_NODE: p
    ctype.base_type: SYM_PTR: <noident>
      ctype.base_type: SYM_BASETYPE: void

[ btw, is there a text mode version of test-inspect? ]

where the SYM_BASETYPE of 'void' has -1 set as bit_size by the frontend.

                        Pekka