<br><br><div class="gmail_quote">On Tue, Jan 31, 2012 at 12:55 AM, Alexander Potapenko <span dir="ltr"><<a href="mailto:glider@google.com">glider@google.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
I dislike the idea of using noinline functions instead of actual<br>
memory accesses.<br>
This may mask problems with uninstrumented accesses, see<br>
<a href="http://code.google.com/p/address-sanitizer/issues/detail?id=33#c9" target="_blank">http://code.google.com/p/address-sanitizer/issues/detail?id=33#c9</a></blockquote><div><br></div><div>But the previous code tested nothing because the LLVM optimized away the memory accesses. </div>
<div>In the C++ test code we use the Ident(a) function which hides the fact that it simply returns 'a'. </div><div>We may want to do the same in ObjC tests. </div><div><br></div><div>--kcc </div><div><br></div><div>
 </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><br>
<div class="HOEnZb"><div class="h5"><br>
On Tue, Jan 31, 2012 at 3:23 AM, Kostya Serebryany <<a href="mailto:kcc@google.com">kcc@google.com</a>> wrote:<br>
> Author: kcc<br>
> Date: Mon Jan 30 17:23:26 2012<br>
> New Revision: 149296<br>
><br>
> URL: <a href="http://llvm.org/viewvc/llvm-project?rev=149296&view=rev" target="_blank">http://llvm.org/viewvc/llvm-project?rev=149296&view=rev</a><br>
> Log:<br>
> [asan] fix issue 35: don't let the optimizer to optimize the test code away.<br>
><br>
> Modified:<br>
>    compiler-rt/trunk/lib/asan/tests/<a href="http://asan_mac_test.mm" target="_blank">asan_mac_test.mm</a><br>
>    compiler-rt/trunk/lib/asan/tests/asan_test.cc<br>
><br>
> Modified: compiler-rt/trunk/lib/asan/tests/<a href="http://asan_mac_test.mm" target="_blank">asan_mac_test.mm</a><br>
> URL: <a href="http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/tests/asan_mac_test.mm?rev=149296&r1=149295&r2=149296&view=diff" target="_blank">http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/tests/asan_mac_test.mm?rev=149296&r1=149295&r2=149296&view=diff</a><br>

> ==============================================================================<br>
> --- compiler-rt/trunk/lib/asan/tests/<a href="http://asan_mac_test.mm" target="_blank">asan_mac_test.mm</a> (original)<br>
> +++ compiler-rt/trunk/lib/asan/tests/<a href="http://asan_mac_test.mm" target="_blank">asan_mac_test.mm</a> Mon Jan 30 17:23:26 2012<br>
> @@ -32,6 +32,10 @@<br>
>   CFAllocatorDeallocate(kCFAllocatorMallocZone, mem);<br>
>  }<br>
><br>
> +__attribute__((noinline))<br>
> +void access_memory(char *a) {<br>
> +  *a = 0;<br>
> +}<br>
><br>
>  // Test the +load instrumentation.<br>
>  // Because the +load methods are invoked before anything else is initialized,<br>
> @@ -51,7 +55,8 @@<br>
><br>
>  +(void) load {<br>
>   for (int i = 0; i < strlen(kStartupStr); i++) {<br>
> -    volatile char ch = kStartupStr[i];  // make sure no optimizations occur.<br>
> +    // TODO: this is currently broken, see Issue 33.<br>
> +    // access_memory(&kStartupStr[i]);  // make sure no optimizations occur.<br>
>   }<br>
>   // Don't print anything here not to interfere with the death tests.<br>
>  }<br>
> @@ -66,7 +71,7 @@<br>
><br>
>  void worker_do_crash(int size) {<br>
>   char * volatile mem = malloc(size);<br>
> -  mem[size] = 0;  // BOOM<br>
> +  access_memory(&mem[size]);  // BOOM<br>
>   free(mem);<br>
>  }<br>
><br>
> @@ -162,7 +167,7 @@<br>
>   dispatch_source_set_timer(timer, milestone, DISPATCH_TIME_FOREVER, 0);<br>
>   char * volatile mem = malloc(10);<br>
>   dispatch_source_set_event_handler(timer, ^{<br>
> -    mem[10] = 1;<br>
> +    access_memory(&mem[10]);<br>
>   });<br>
>   dispatch_resume(timer);<br>
>   sleep(2);<br>
> @@ -186,7 +191,7 @@<br>
>     dispatch_source_cancel(timer);<br>
>   });<br>
>   dispatch_source_set_cancel_handler(timer, ^{<br>
> -    mem[10] = 1;<br>
> +    access_memory(&mem[10]);<br>
>   });<br>
>   dispatch_resume(timer);<br>
>   sleep(2);<br>
> @@ -197,7 +202,7 @@<br>
>   dispatch_group_t group = dispatch_group_create();<br>
>   char * volatile mem = malloc(10);<br>
>   dispatch_group_async(group, queue, ^{<br>
> -    mem[10] = 1;<br>
> +    access_memory(&mem[10]);<br>
>   });<br>
>   dispatch_group_wait(group, DISPATCH_TIME_FOREVER);<br>
>  }<br>
><br>
> Modified: compiler-rt/trunk/lib/asan/tests/asan_test.cc<br>
> URL: <a href="http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/tests/asan_test.cc?rev=149296&r1=149295&r2=149296&view=diff" target="_blank">http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/tests/asan_test.cc?rev=149296&r1=149295&r2=149296&view=diff</a><br>

> ==============================================================================<br>
> --- compiler-rt/trunk/lib/asan/tests/asan_test.cc (original)<br>
> +++ compiler-rt/trunk/lib/asan/tests/asan_test.cc Mon Jan 30 17:23:26 2012<br>
> @@ -1668,7 +1668,7 @@<br>
>   *Ident(&a) = *Ident(&a);<br>
>  }<br>
><br>
> - __attribute__((no_address_safety_analysis))<br>
> +__attribute__((no_address_safety_analysis))<br>
>  static void NoAddressSafety() {<br>
>   char *foo = new char[10];<br>
>   Ident(foo)[10] = 0;<br>
><br>
><br>
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<br>
<br>
<br>
</div></div><span class="HOEnZb"><font color="#888888">--<br>
Alexander Potapenko<br>
Software Engineer<br>
Google Moscow<br>
</font></span></blockquote></div><br>