review for 7071307: MethodHandle bimorphic inlining should consider the frequency

[Charles Oliver Nutter]

On Thu, Jul 28, 2011 at 7:47 PM, Tom Rodriguez <tom.rodriguez at oracle.com> wrote:
> http://cr.openjdk.java.net/~never/7071307
> 46 lines changed: 27 ins; 6 del; 13 mod; 3568 unchg
>
> 7071307: MethodHandle bimorphic inlining should consider the frequency
> Reviewed-by:
>
> The fix for 7050554 added a bimorphic inline path but didn't take into
> account the frequency of the guarding test.  This ends up treating
> both sides of the if as equally frequent which can lead to over
> inlining and overflowing the method inlining limits.  The fix is to
> grab the frequency from the If and apply that to the branches.  This
> addresses a major source of overinlining that can result in bad
> performance with JSR 292.  We may do a later extension to this to
> actually do per call chain profiling of selectAlternative but that's a
> more complicated fix.
>
> I also fixed a problem with the ideal graph printer where debug_orig
> printing would go into an infinite loop.
>
> Tested with jruby and vm.mlvm tests.

Building on Ubuntu (an admittedly old install) yields some warnings
that are turned into errors:

g++ -DLINUX -D_GNU_SOURCE -DIA32 -DPRODUCT -I.
-I/home/headius/hsx-hotspot/src/share/vm/prims
-I/home/headius/hsx-hotspot/src/share/vm
-I/home/headius/hsx-hotspot/src/cpu/x86/vm
-I/home/headius/hsx-hotspot/src/os_cpu/linux_x86/vm
-I/home/headius/hsx-hotspot/src/os/linux/vm
-I/home/headius/hsx-hotspot/src/os/posix/vm -I../generated
-DHOTSPOT_RELEASE_VERSION="\"22.0-b01-internal\""
-DHOTSPOT_BUILD_TARGET="\"product\""
-DHOTSPOT_BUILD_USER="\"headius\"" -DHOTSPOT_LIB_ARCH=\"i386\"
-DJRE_RELEASE_VERSION="\"1.7.0\"" -DHOTSPOT_VM_DISTRO="\"OpenJDK\""
-DTARGET_OS_FAMILY_linux -DTARGET_ARCH_x86 -DTARGET_ARCH_MODEL_x86_32
-DTARGET_OS_ARCH_linux_x86 -DTARGET_OS_ARCH_MODEL_linux_x86_32
-DTARGET_COMPILER_gcc -DCOMPILER2 -DCOMPILER1 -fPIC -fno-rtti
-fno-exceptions -D_REENTRANT -fcheck-new -m32 -march=i586 -pipe -O3
-fno-strict-aliasing -DVM_LITTLE_ENDIAN -Werror -Wpointer-arith
-Wconversion -Wsign-compare    -c -MMD -MP -MF
../generated/dependencies/precompiled.hpp.gch.d -x c++-header
/home/headius/hsx-hotspot/src/share/vm/precompiled.hpp -o
precompiled.hpp.gch
cc1plus: warnings being treated as errors
/home/headius/hsx-hotspot/src/share/vm/ci/ciCallProfile.hpp: In member
function 'ciCallProfile ciCallProfile::rescale(double)':
/home/headius/hsx-hotspot/src/share/vm/ci/ciCallProfile.hpp:87:
warning: converting to 'int' from 'double'
/home/headius/hsx-hotspot/src/share/vm/ci/ciCallProfile.hpp:89:
warning: converting to 'int' from 'double'

The lines in question are doing (int) *= (double), which gcc complains
about. Ubuntu probably has warnings set up to be errors, so it fails
the build.

I modified them in my local copy to do the long form with an explicit
cast back to int, but you can fix in whatever way is best.

- Charlie