> Do we have any idea how much of a change? Do we care? I'm presuming the increased debuggability is worth it.
It adds 0-4 additional stack movs in function prologue code which should have a very low impact, it's only on debug/fastdebug builds. > The above block will also apply to an "ia64" build. We don't support that anymore, but I don't know if any licensees support it. I've changed the checks in vm.make and WinGammaPlatformVC10.java > Do we need to do anything about the new, but unused platform to make lint-like tools not squawk? I'll open a new bug to clean up the VC7/8/9 files in ProjectCreator. New webrev: http://cr.openjdk.java.net/~ctornqvi/webrev/8027480/webrev.01/ Thanks, Christian -----Original Message----- From: Daniel D. Daugherty [mailto:daniel.daughe...@oracle.com] Sent: Wednesday, August 20, 2014 9:48 AM To: Christian Tornqvist Cc: hotspot-...@openjdk.java.net Subject: Re: RFR(S): 8027480 - Build Windows x64 fastdebug builds using /homeparams > http://cr.openjdk.java.net/~ctornqvi/webrev/8027480/webrev.00/ General Comment The MSDN note says: > /homeparams does imply a performance disadvantage, because it > does require a cycle to load the register parameters on to the stack. Do we have any idea how much of a change? Do we care? I'm presuming the increased debuggability is worth it. make/windows/makefiles/vm.make line 38: !else line 39: CXX_FLAGS=$(CXX_FLAGS) /D "ASSERT" /homeparams line 40: !endif The above block will also apply to an "ia64" build. We don't support that anymore, but I don't know if any licensees support it. src/share/tools/ProjectCreator/BuildConfig.java No comments. src/share/tools/ProjectCreator/WinGammaPlatformVC10.java line 373: if(!platformName.equals("Win32")) { line 374: addAttr(rv, "AdditionalOptions", "/homeparams"); The above block will also apply to an "ia64" build. src/share/tools/ProjectCreator/WinGammaPlatformVC7.java src/share/tools/ProjectCreator/WinGammaPlatformVC8.java Do we need to do anything about the new, but unused platform to make lint-like tools not squawk? Thumbs up. Dan On 8/19/14 5:39 PM, Christian Tornqvist wrote: > Hi everyone, > > > > This change adds /homeparams > (http://msdn.microsoft.com/en-us/library/6exwh0y6.aspx) to compiler > flags when building fastdebug on Windows x64. This causes the compiler > to generate code to spill the first 4 arguments to the stack (they're > normally only passed in registers), which should make it easier to debug. > > > > I also changed the ProjectCreator to enable building with this using > Visual Studio. The size of jvm.dll increases with about 3% (about 504k increase). > > > > Verified that it builds correctly using Visual Studio and JPRT, the > generation of the spill code has been verified by comparing prologue > code for several functions in the JVM with/without using /homeparams. > > > > Webrev: > > http://cr.openjdk.java.net/~ctornqvi/webrev/8027480/webrev.00/ > > > > Bug: > > https://bugs.openjdk.java.net/browse/JDK-8027480 > > > > Thanks, > > Christian > > >
