RFR 8204850: BarrierSet::make_* should be static

[Aleksey Shipilev]

(resending with proper To: field)

On 06/12/2018 08:38 AM, Aleksey Shipilev wrote:
> RFE:
>   https://bugs.openjdk.java.net/browse/JDK-8204850
> 
> In Epsilon, we have the call like:
> 
> EpsilonBarrierSet::EpsilonBarrierSet() : BarrierSet(
>           make_barrier_set_assembler<BarrierSetAssembler>(),
>           make_barrier_set_c1<BarrierSetC1>(),
>           make_barrier_set_c2<BarrierSetC2>(),
>           BarrierSet::FakeRtti(BarrierSet::EpsilonBarrierSet)) {};
> 
> ...and some compilers (notably Mac OS builds) complain that:
> 
> /Users/yosemite/jdk-sandbox/src/hotspot/share/gc/epsilon/epsilonBarrierSet.cpp:40:11: error: base
> class 'BarrierSet' is uninitialized when used here to access
> 'BarrierSet::make_barrier_set_assembler<BarrierSetAssembler>' [-Werror,-Wuninitialized]
>           make_barrier_set_assembler<BarrierSetAssembler>(),
>           ^
> 
> This warning is legit: we are calling instance method of BarrierSet before initializing it. But,
> those methods are just factory methods, and they could be static, resolving the warning.
> 
> Fix:
> 
> diff -r 7f166e010af4 src/hotspot/share/gc/shared/barrierSet.hpp
> --- a/src/hotspot/share/gc/shared/barrierSet.hpp	Mon Jun 11 22:35:07 2018 -0400
> +++ b/src/hotspot/share/gc/shared/barrierSet.hpp	Tue Jun 12 08:34:40 2018 +0200
> @@ -103,17 +103,17 @@
>    ~BarrierSet() { }
> 
>    template <class BarrierSetAssemblerT>
> -  BarrierSetAssembler* make_barrier_set_assembler() {
> +  static BarrierSetAssembler* make_barrier_set_assembler() {
>      return NOT_ZERO(new BarrierSetAssemblerT()) ZERO_ONLY(NULL);
>    }
> 
>    template <class BarrierSetC1T>
> -  BarrierSetC1* make_barrier_set_c1() {
> +  static BarrierSetC1* make_barrier_set_c1() {
>      return COMPILER1_PRESENT(new BarrierSetC1T()) NOT_COMPILER1(NULL);
>    }
> 
>    template <class BarrierSetC2T>
> -  BarrierSetC2* make_barrier_set_c2() {
> +  static BarrierSetC2* make_barrier_set_c2() {
>      return COMPILER2_PRESENT(new BarrierSetC2T()) NOT_COMPILER2(NULL);
>    }
> 
> 
> Testing: x86_64 build, Epsilon MacOS build
> 
> Thanks,
> -Aleksey
>