# HG changeset patch
# User aph
# Date 1338387602 14400
# Node ID 1000c4de30f81f192548af94f79ab61e4af0e783
# Parent  a14598bd41e5b475954cfdf98cf124141d02059e
Don't save locals at a return.

diff -r a14598bd41e5 -r 1000c4de30f8 make/linux/makefiles/fastdebug.make
--- a/make/linux/makefiles/fastdebug.make	Tue May 29 11:06:21 2012 -0400
+++ b/make/linux/makefiles/fastdebug.make	Wed May 30 10:20:02 2012 -0400
@@ -31,7 +31,7 @@
 # (OPT_CFLAGS/SLOWER is also available, to alter compilation of buggy files)
 
 ifeq ($(BUILDARCH), ia64)
-  # Bug in GCC, causes hang.  -O1 will override the -O3 specified earlier
+  # Bug in GCC, causes hang.  -O1 will override the -O0 specified earlier
   OPT_CFLAGS/callGenerator.o += -O1
   OPT_CFLAGS/ciTypeFlow.o += -O1
   OPT_CFLAGS/compile.o += -O1
diff -r a14598bd41e5 -r 1000c4de30f8 make/linux/makefiles/gcc.make
--- a/make/linux/makefiles/gcc.make	Tue May 29 11:06:21 2012 -0400
+++ b/make/linux/makefiles/gcc.make	Wed May 30 10:20:02 2012 -0400
@@ -160,7 +160,7 @@
 CFLAGS_WARN/BYFILE = $(CFLAGS_WARN/$@)$(CFLAGS_WARN/DEFAULT$(CFLAGS_WARN/$@)) 
 
 # The flags to use for an Optimized g++ build
-OPT_CFLAGS += -O3
+OPT_CFLAGS += -O0
 
 # Hotspot uses very unstrict aliasing turn this optimization off
 OPT_CFLAGS += -fno-strict-aliasing
diff -r a14598bd41e5 -r 1000c4de30f8 make/solaris/makefiles/gcc.make
--- a/make/solaris/makefiles/gcc.make	Tue May 29 11:06:21 2012 -0400
+++ b/make/solaris/makefiles/gcc.make	Wed May 30 10:20:02 2012 -0400
@@ -121,7 +121,7 @@
 CFLAGS_WARN/BYFILE = $(CFLAGS_WARN/$@)$(CFLAGS_WARN/DEFAULT$(CFLAGS_WARN/$@))  
 
 # The flags to use for an Optimized g++ build
-OPT_CFLAGS += -O3
+OPT_CFLAGS += -O0
 
 # Hotspot uses very unstrict aliasing turn this optimization off
 OPT_CFLAGS += -fno-strict-aliasing
diff -r a14598bd41e5 -r 1000c4de30f8 src/cpu/zero/vm/asm_helper.cpp
--- a/src/cpu/zero/vm/asm_helper.cpp	Tue May 29 11:06:21 2012 -0400
+++ b/src/cpu/zero/vm/asm_helper.cpp	Wed May 30 10:20:02 2012 -0400
@@ -403,6 +403,8 @@
     return thread->pending_exception();
 }
 
+extern "C" void ps();
+
 extern "C" oop Helper_SafePoint(JavaThread *thread)
 {
     {
@@ -412,6 +414,15 @@
     return thread->pending_exception();
 }
 
+extern "C" oop Helper_SafePoint2(JavaThread *thread)
+{
+    {
+      HandleMarkCleaner __hmc(thread);
+    }
+    SafepointSynchronize::block(thread);
+    return thread->pending_exception();
+}
+
 extern "C" void Helper_RaiseArrayBoundException(JavaThread *thread, int index)
 {
   char message[jintAsStringSize];
diff -r a14598bd41e5 -r 1000c4de30f8 src/cpu/zero/vm/thumb2.cpp
--- a/src/cpu/zero/vm/thumb2.cpp	Tue May 29 11:06:21 2012 -0400
+++ b/src/cpu/zero/vm/thumb2.cpp	Wed May 30 10:20:02 2012 -0400
@@ -3447,13 +3447,15 @@
   jstack->depth = 0;
 }
 
+// SAVE_STACK and RESTORE_STACK save the stack state so that it's
+// possible to do a stack flush to memory and restore that stack state
+// to the same registers.
 #define SAVE_STACK(JSTACK)					\
   unsigned saved_stack_elements[JSTACK->depth];			\
   unsigned saved_stack_depth;					\
   memcpy(saved_stack_elements, JSTACK->stack,			\
 	 JSTACK->depth * sizeof saved_stack_elements[0]);	\
   saved_stack_depth = JSTACK->depth;
-
 #define RESTORE_STACK(JSTACK, CODEBUF)					\
   Thumb2_Pop_Multiple(CODEBUF, saved_stack_elements, saved_stack_depth); \
   memcpy(JSTACK->stack, saved_stack_elements,				\
@@ -4217,7 +4219,7 @@
   //
   //  n.b. for a return there is no need save or restore locals
 
-  bool is_return = offset == 0;
+  bool is_return = offset == 0; // This is some kind of return bytecode
 
   int r_tmp = Thumb2_Tmp(jinfo, 0);
   unsigned dest;
@@ -4261,23 +4263,19 @@
     SAVE_STACK(jinfo->jstack);
     Thumb2_Flush(jinfo);
 
+    // We don't save or restore locals if we're returning.
+    if (! is_return)
+      Thumb2_save_locals(jinfo, stackdepth);
+
     // now the safepoint polling code itself
-
-    // We save the locals at a return bytecode even though we aren't
-    // going to restore them: we do so because otherwise there's a
-    // risk that the GC might scan garbage.
-    Thumb2_save_locals(jinfo, stackdepth);
-
     mov_imm(jinfo->codebuf, ARM_R1, bci+CONSTMETHOD_CODEOFFSET);
     add_imm(jinfo->codebuf, ARM_R2, ISTATE_REG(jinfo),
 	    ISTATE_OFFSET(jinfo, stackdepth, 0));
     bl(jinfo->codebuf, handlers[H_SAFEPOINT]);
 
-    // We don't restore the locals if we're returning.
     if (! is_return)
       Thumb2_restore_locals(jinfo, stackdepth);
 
-    // But we always restore the register state of the stack.
     RESTORE_STACK(jinfo->jstack, jinfo->codebuf);
 
     if (offset < 0) {
diff -r a14598bd41e5 -r 1000c4de30f8 src/os/linux/vm/os_linux.cpp
--- a/src/os/linux/vm/os_linux.cpp	Tue May 29 11:06:21 2012 -0400
+++ b/src/os/linux/vm/os_linux.cpp	Wed May 30 10:20:02 2012 -0400
@@ -4215,8 +4215,11 @@
   Linux::fast_thread_clock_init();
 
   // Allocate a single page and mark it as readable for safepoint polling
-  address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
-  guarantee( polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page" );
+  julong foo = (julong) ::mmap(NULL, 65536, PROT_READ, 
+				 MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, -1, 0);
+  address polling_page = (address)(foo & -65536L);
+  if ((julong)polling_page < foo)
+    polling_page += 65536;
 
   os::set_polling_page( polling_page );
 
diff -r a14598bd41e5 -r 1000c4de30f8 src/share/vm/gc_implementation/shared/markSweep.cpp
--- a/src/share/vm/gc_implementation/shared/markSweep.cpp	Tue May 29 11:06:21 2012 -0400
+++ b/src/share/vm/gc_implementation/shared/markSweep.cpp	Wed May 30 10:20:02 2012 -0400
@@ -30,6 +30,11 @@
 #include "oops/objArrayKlass.inline.hpp"
 #include "oops/oop.inline.hpp"
 
+
+void *arse[2];
+
+void sa(void*a, void *b) { arse[0] = a; arse [1] = b; }
+
 Stack<oop>              MarkSweep::_marking_stack;
 Stack<DataLayout*>      MarkSweep::_revisit_mdo_stack;
 Stack<Klass*>           MarkSweep::_revisit_klass_stack;
diff -r a14598bd41e5 -r 1000c4de30f8 src/share/vm/gc_implementation/shared/markSweep.inline.hpp
--- a/src/share/vm/gc_implementation/shared/markSweep.inline.hpp	Tue May 29 11:06:21 2012 -0400
+++ b/src/share/vm/gc_implementation/shared/markSweep.inline.hpp	Wed May 30 10:20:02 2012 -0400
@@ -43,9 +43,15 @@
   }
 }
 
+extern "C" void *arse[2];
+
+extern "C" void sa(void*a, void *b);
+
 template <class T> inline void MarkSweep::follow_root(T* p) {
   assert(!Universe::heap()->is_in_reserved(p),
          "roots shouldn't be things within the heap");
+  if (arse[0] <= (void *)p && arse[1] >= (void *)p)
+    fprintf(stderr, "Whip\n");
 #ifdef VALIDATE_MARK_SWEEP
   if (ValidateMarkSweep) {
     guarantee(!_root_refs_stack->contains(p), "should only be in here once");
diff -r a14598bd41e5 -r 1000c4de30f8 src/share/vm/interpreter/bytecodeInterpreter.cpp
--- a/src/share/vm/interpreter/bytecodeInterpreter.cpp	Tue May 29 11:06:21 2012 -0400
+++ b/src/share/vm/interpreter/bytecodeInterpreter.cpp	Wed May 30 10:20:02 2012 -0400
@@ -1507,7 +1507,13 @@
       CASE(_freturn):
       {
           // Allow a safepoint before returning to frame manager.
-          SAFEPOINT;
+    if ( SafepointSynchronize::is_synchronizing()) {
+        {
+          /* zap freed handles rather than GC'ing them */
+          HandleMarkCleaner __hmc(THREAD);
+        }
+        CALL_VM(SafepointSynchronize::block(THREAD), handle_exception);
+    }
 
           goto handle_return;
       }
diff -r a14598bd41e5 -r 1000c4de30f8 src/share/vm/runtime/frame.cpp
--- a/src/share/vm/runtime/frame.cpp	Tue May 29 11:06:21 2012 -0400
+++ b/src/share/vm/runtime/frame.cpp	Wed May 30 10:20:02 2012 -0400
@@ -785,6 +785,9 @@
       }
       if (in_stack) {
         _f->do_oop(addr);
+      } else {
+	fprintf(stderr, "Arse! %p\n",
+		_fr->interpreter_frame_tos_address());
       }
     }
   }
diff -r a14598bd41e5 -r 1000c4de30f8 src/share/vm/runtime/vmThread.cpp
--- a/src/share/vm/runtime/vmThread.cpp	Tue May 29 11:06:21 2012 -0400
+++ b/src/share/vm/runtime/vmThread.cpp	Wed May 30 10:20:02 2012 -0400
@@ -245,6 +245,39 @@
   }
 }
 
+class BangerThread : NamedThread
+{
+public:
+
+  static BangerThread *the_thread;
+
+  static void create() {
+    the_thread = new BangerThread();
+    os::create_thread (the_thread, os::watcher_thread);
+    Thread::start(the_thread);
+  }
+
+  BangerThread() : NamedThread() {
+    set_name("banger");
+  }
+
+  void run() {
+    struct timespec req;
+    req.tv_nsec = 0.5e9;
+    req.tv_sec = 0;
+
+    for (;;)
+      {
+	nanosleep(&req, NULL);
+	// VM_ForceSafepoint op;
+	// VMThread::execute(&op);
+	Universe::heap()->collect(GCCause::_java_lang_system_gc);
+      }
+  }
+};
+
+BangerThread *BangerThread::the_thread;
+
 void VMThread::run() {
   assert(this == vm_thread(), "check");
 
@@ -269,6 +302,8 @@
   // possible to set the VM thread priority higher than any Java thread.
   os::set_native_priority( this, prio );
 
+  BangerThread::create();
+
   // Wait for VM_Operations until termination
   this->loop();