[Qemu-devel] tci build failure (was Re: [PULL v5 00/22] virtio, vhost, pci: fixes, features)

["Michael S. Tsirkin" <mst@redhat.com>]

On Thu, Feb 02, 2017 at 04:25:34PM +0000, Peter Maydell wrote:
> On 2 February 2017 at 13:56, Peter Maydell <peter.maydell@linaro.org> wrote:
> > On 31 January 2017 at 20:18, Michael S. Tsirkin <mst@redhat.com> wrote:
> >> virtio, vhost, pci: fixes, features
> >>
> >> generic pci root port support
> >> disable shpc by default
> >> safer version of ARRAY_SIZE and QEMU_BUILD_BUG_ON
> >> fixes and cleanups all over the place
> >>
> >> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> 
> > Applied, thanks.
> 
> ...travis builds now fail for the --enable-tcg-interpreter config:
> https://travis-ci.org/qemu/qemu/jobs/197648661
> 
> In file included from /home/travis/build/qemu/qemu/tcg/tcg.c:255:0:
> /home/travis/build/qemu/qemu/tcg/tci/tcg-target.inc.c: In function ‘tcg_out_op’:
> /home/travis/build/qemu/qemu/tcg/tci/tcg-target.inc.c:569:117: error:
> negative width in bit-field ‘<anonymous>’
> /home/travis/build/qemu/qemu/tcg/tci/tcg-target.inc.c:569:255: error:
> negative width in bit-field ‘<anonymous>’
> In file included from /home/travis/build/qemu/qemu/tcg/tcg.c:255:0:
> /home/travis/build/qemu/qemu/tcg/tci/tcg-target.inc.c:578:115: error:
> negative width in bit-field ‘<anonymous>’
> /home/travis/build/qemu/qemu/tcg/tci/tcg-target.inc.c:578:255: error:
> negative width in bit-field ‘<anonymous>’
> 
> These look to be because we were trying to use ARRAY_SIZE()
> on a non-array, which was previously undetected. The use is
> only in an assert() so fairly harmless.
> 
> Would somebody who cares about TCI like to provide a fix?
> 
> thanks
> -- PMM

I think the following should do it. Completely untested.

-->

tcg/tci: fix ARRAY_SIZE misuse

tb_jmp_insn_offset and tb_jmp_reset_offset are
pointers, not arrays, so using ARRAY_SIZE on them will
not do the right thing.

They point to arrays within TranslationBlock so check
the size of these instead.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

--

diff --git a/tcg/tci/tcg-target.inc.c b/tcg/tci/tcg-target.inc.c
index 26ee9b1..a2ba654 100644
--- a/tcg/tci/tcg-target.inc.c
+++ b/tcg/tci/tcg-target.inc.c
@@ -556,6 +556,7 @@ static void tcg_out_op(TCGContext *s, TCGOpcode opc, const TCGArg *args,
                        const int *const_args)
 {
     uint8_t *old_code_ptr = s->code_ptr;
+    TranslationBlock *tb;
 
     tcg_out_op_t(s, opc);
 
@@ -566,7 +567,7 @@ static void tcg_out_op(TCGContext *s, TCGOpcode opc, const TCGArg *args,
     case INDEX_op_goto_tb:
         if (s->tb_jmp_insn_offset) {
             /* Direct jump method. */
-            tcg_debug_assert(args[0] < ARRAY_SIZE(s->tb_jmp_insn_offset));
+            tcg_debug_assert(args[0] < ARRAY_SIZE(tb->jmp_insn_offset));
             /* Align for atomic patching and thread safety */
             s->code_ptr = QEMU_ALIGN_PTR_UP(s->code_ptr, 4);
             s->tb_jmp_insn_offset[args[0]] = tcg_current_code_size(s);
@@ -575,7 +576,7 @@ static void tcg_out_op(TCGContext *s, TCGOpcode opc, const TCGArg *args,
             /* Indirect jump method. */
             TODO();
         }
-        tcg_debug_assert(args[0] < ARRAY_SIZE(s->tb_jmp_reset_offset));
+        tcg_debug_assert(args[0] < ARRAY_SIZE(tb->jmp_reset_offset));
         s->tb_jmp_reset_offset[args[0]] = tcg_current_code_size(s);
         break;
     case INDEX_op_br: