8209520: Build fails when native code coverage is enabled

[Vladimir Kozlov]

macroassembler changes are good.

Thanks,
Vladimir

On 8/23/18 1:51 PM, Leonid Mesnik wrote:
> Hi
> 
> Could you please review following fix which fix code so gcc doesn't complain when JDK is build with enabled native code 
> coverage.
> 
> webrev: http://cr.openjdk.java.net/~lmesnik/8209520/webrev.00/ <http://cr.openjdk.java.net/%7Elmesnik/8209520/webrev.00/>
> bug: https://bugs.openjdk.java.net/browse/JDK-8209520
> 
> These warning appeared because of change optimization settings used for getting code coverage.
> 
> 1) src/hotspot/cpu/x86/macroAssembler_x86.cpp, src/hotspot/share/gc/shared/genCollectedHeap.cpp
> 
> gcc complained about uninitialized variables, like
> * For target hotspot_variant-server_libjvm_objs_macroAssembler_x86.o:
> /home/lmesnik/ws/jdk-8209520/open/src/hotspot/cpu/x86/macroAssembler_x86.cpp: In member function 'void 
> ControlWord::print() const':
> /home/lmesnik/ws/jdk-8209520/open/src/hotspot/cpu/x86/macroAssembler_x86.cpp:5769:11: error: 'pc' may be used 
> uninitialized in this function [-Werror=maybe-uninitialized]
>       printf("%04x  masks = %s, %s, %s", _value & 0xFFFF, f, rc, pc);
>       ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> /home/lmesnik/ws/jdk-8209520/open/src/hotspot/cpu/x86/macroAssembler_x86.cpp:5769:11: error: 'rc' may be used 
> uninitialized in this function [-Werror=maybe-uninitialized]
> 
> So I just fixed codepath to show more explicitly that variables are initialized before usage.
> 
> 
> 2) src/java.desktop/share/native/libsplashscreen/splashscreen_png.c:
> The changes to prevent waning about clobbering in splashscreen_png.c are similar to fix in:
> 
>  1. JDK-8080695 <https://bugs.openjdk.java.net/browse/JDK-8080695>
>     splashscreen_png.c compile error with gcc 4.9.2
> 
> 
> 
> The another approach would be to fix build to ignore these warnings for code coverage build. While I think it makes 
> build system even more complicated.
> Leonid