423 

   424   // Check if the intrinsic corresponding to 'method' has been disabled on

   425   // the command line by using the DisableIntrinsic flag (either globally

   426   // or on a per-method level, see src/share/vm/compiler/abstractCompiler.hpp

   427   // for details).

   428   // Usually, the compilation context is the caller of the method 'method'.

   429   // The only case when for a non-recursive method 'method' the compilation context

   430   // is not the caller of the 'method' (but it is the method itself) is

   431   // java.lang.ref.Referene::get.

   432   // For java.lang.ref.Reference::get, the intrinsic version is used

   433   // instead of the compiled version so that the value in the referent

   434   // field can be registered by the G1 pre-barrier code. The intrinsified

   435   // version of Reference::get also adds a memory barrier to prevent

   436   // commoning reads from the referent field across safepoint since GC

   437   // can change the referent field's value. See Compile::Compile()

   438   // in src/share/vm/opto/compile.cpp or

   439   // GraphBuilder::GraphBuilder() in src/share/vm/c1/c1_GraphBuilder.cpp

   440   // for more details.

   441   ccstr disable_intr = NULL;

   442   if ((DisableIntrinsic[0] != '\0' && strstr(DisableIntrinsic, vmIntrinsics::name_at(id)) != NULL) ||

   443       (!compilation_context.is_null() &&

   444        CompilerOracle::has_option_value(compilation_context, "DisableIntrinsic", disable_intr) &&

   445        strstr(disable_intr, vmIntrinsics::name_at(id)) != NULL)

   446   ) {

   447     return true;

   448   }