Flate: fix valgrind miniz Conditional-jump-or-move-depends... error

Flate: fix valgrind miniz Conditional-jump-or-move-depends... error

Committed: https://skia.googlesource.com/skia/+/e0638f8ecfb609c89cab1aa8b498ad3f368b89d3

[hal.canary, 2015-02-27 18:11:08]

halcanary@google.com changed reviewers:
+ mtklein@google.com

[hal.canary, 2015-02-27 18:11:51]

The CQ bit was checked by halcanary@google.com

[commit-bot: I haz the power, 2015-02-27 18:12:41]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/964933003/1

[commit-bot: I haz the power, 2015-02-27 18:12:42]

Note for Reviewers:
The CQ is waiting for an approval.
If you believe that the CL is not ready yet, or if you would like to L-G-T-M
with comments then please uncheck the CQ checkbox.

Waiting for LGTM from valid reviewer(s) till 2015-02-28 00:12 UTC

[mtklein, 2015-02-27 18:12:50]

https://codereview.chromium.org/964933003/diff/1/src/core/SkFlate.cpp
File src/core/SkFlate.cpp (right):

https://codereview.chromium.org/964933003/diff/1/src/core/SkFlate.cpp#newcode28
src/core/SkFlate.cpp:28: void* alloc = sk_calloc_throw(items * size);
Do we perhaps need to return something?

[hal.canary, 2015-02-27 18:18:35]

https://codereview.chromium.org/964933003/diff/1/src/core/SkFlate.cpp
File src/core/SkFlate.cpp (right):

https://codereview.chromium.org/964933003/diff/1/src/core/SkFlate.cpp#newcode28
src/core/SkFlate.cpp:28: void* alloc = sk_calloc_throw(items * size);
On 2015/02/27 18:12:50, mtklein wrote:
> Do we perhaps need to return something?

HOW DOES THAT COMPILE!

[hal.canary, 2015-02-27 18:18:43]

The CQ bit was checked by halcanary@google.com

[commit-bot: I haz the power, 2015-02-27 18:19:51]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/964933003/20001

[commit-bot: I haz the power, 2015-02-27 18:19:52]

Note for Reviewers:
The CQ is waiting for an approval.
If you believe that the CL is not ready yet, or if you would like to L-G-T-M
with comments then please uncheck the CQ checkbox.

Waiting for LGTM from valid reviewer(s) till 2015-02-28 00:19 UTC

[mtklein, 2015-02-27 18:27:36]

lgtm

IIRC, there are actually parts of the DEFLATE algorithm that function correctly
when using uninitialized memory.  This is probably that.  I think we'd have to
suppress zlib too if we start building that ourselves.

http://www.zlib.net/zlib_faq.html#faq36

[hal.canary, 2015-02-27 18:35:51]

On 2015/02/27 18:27:36, mtklein wrote:
> IIRC, there are actually parts of the DEFLATE algorithm that function
correctly
> when using uninitialized memory.  This is probably that.  I think we'd have to
> suppress zlib too if we start building that ourselves.
> 
> http://www.zlib.net/zlib_faq.html#faq36

Let's proceed under the assumptions that (1) calloc isn't much overhead compared
ti the rest of deflate, and (2) for consistency, sk_[cm]alloc is better than
[cm]alloc.

[commit-bot: I haz the power, 2015-02-27 18:39:33]

Committed patchset #2 (id:20001) as
https://skia.googlesource.com/skia/+/e0638f8ecfb609c89cab1aa8b498ad3f368b89d3

[mtklein, 2015-02-27 18:42:29]

On 2015/02/27 18:35:51, Hal Canary wrote:
> On 2015/02/27 18:27:36, mtklein wrote:
> > IIRC, there are actually parts of the DEFLATE algorithm that function
> correctly
> > when using uninitialized memory.  This is probably that.  I think we'd have
to
> > suppress zlib too if we start building that ourselves.
> > 
> > http://www.zlib.net/zlib_faq.html#faq36
> 
> Let's proceed under the assumptions that (1) calloc isn't much overhead
compared
> ti the rest of deflate, and (2) for consistency, sk_[cm]alloc is better than
> [cm]alloc.

Oh sure, yeah.  Just pointing out this might not be as terrifying as it seems. 
I bet the system zlib was doing the same, but Valgrind just couldn't see it.

[Stephen Chennney, 2015-02-27 19:02:26]

A revert of this CL (patchset #2 id:20001) has been created in
https://codereview.chromium.org/964953002/ by schenney@chromium.org.

The reason for reverting is: Breaks the chrome build.

../../third_party/skia/src/core/SkFlate.cpp:37:22: error: assigning to
'MOZ_Z_alloc_func' (aka 'MOZ_Z_voidpf (*)(MOZ_Z_voidpf, MOZ_Z_uInt,
MOZ_Z_uInt)') from incompatible type 'void *(*)(void *, size_t, size_t)': type
mismatch at 2nd parameter ('MOZ_Z_uInt' (aka 'unsigned int') vs 'size_t' (aka
'unsigned long'))
    flateData.zalloc = &skia_alloc_func;
                     ^ ~~~~~~~~~~~~~~~~
../../third_party/skia/src/core/SkFlate.cpp:180:28: error: assigning to
'MOZ_Z_alloc_func' (aka 'MOZ_Z_voidpf (*)(MOZ_Z_voidpf, MOZ_Z_uInt,
MOZ_Z_uInt)') from incompatible type 'void *(*)(void *, size_t, size_t)': type
mismatch at 2nd parameter ('MOZ_Z_uInt' (aka 'unsigned int') vs 'size_t' (aka
'unsigned long'))
    fImpl->fZStream.zalloc = &skia_alloc_func;
.