7125934: Add a fast unordered timestamp capability to Hotspot on x86/x64

Summary: Add rdtsc detection and inline generation.
Reviewed-by: kamg, dholmes
Contributed-by: karen.kinnear@oracle.com

src/cpu/x86/vm/vm_version_x86.cpp

@@ -50,7 +50,7 @@ const char*           VM_Version::_features_str = "";
 VM_Version::CpuidInfo VM_Version::_cpuid_info   = { 0, };
 
 static BufferBlob* stub_blob;
-static const int stub_size = 400;
+static const int stub_size = 500;
 
 extern "C" {
   typedef void (*getPsrInfo_stub_t)(void*);
@@ -73,7 +73,7 @@ class VM_Version_StubGenerator: public StubCodeGenerator {
     const uint32_t CPU_FAMILY_486   = (4 << CPU_FAMILY_SHIFT);
 
     Label detect_486, cpu486, detect_586, std_cpuid1, std_cpuid4;
-    Label ext_cpuid1, ext_cpuid5, done;
+    Label ext_cpuid1, ext_cpuid5, ext_cpuid7, done;
 
     StubCodeMark mark(this, "VM_Version", "getPsrInfo_stub");
 #   define __ _masm->
@@ -235,8 +235,10 @@ class VM_Version_StubGenerator: public StubCodeGenerator {
     __ jcc(Assembler::belowEqual, done);
     __ cmpl(rax, 0x80000004);     // Is cpuid(0x80000005) supported?
     __ jccb(Assembler::belowEqual, ext_cpuid1);
-    __ cmpl(rax, 0x80000007);     // Is cpuid(0x80000008) supported?
+    __ cmpl(rax, 0x80000006);     // Is cpuid(0x80000007) supported?
     __ jccb(Assembler::belowEqual, ext_cpuid5);
+    __ cmpl(rax, 0x80000007);     // Is cpuid(0x80000008) supported?
+    __ jccb(Assembler::belowEqual, ext_cpuid7);
     //
     // Extended cpuid(0x80000008)
     //
@@ -248,6 +250,18 @@ class VM_Version_StubGenerator: public StubCodeGenerator {
     __ movl(Address(rsi, 8), rcx);
     __ movl(Address(rsi,12), rdx);
 
+    //
+    // Extended cpuid(0x80000007)
+    //
+    __ bind(ext_cpuid7);
+    __ movl(rax, 0x80000007);
+    __ cpuid();
+    __ lea(rsi, Address(rbp, in_bytes(VM_Version::ext_cpuid7_offset())));
+    __ movl(Address(rsi, 0), rax);
+    __ movl(Address(rsi, 4), rbx);
+    __ movl(Address(rsi, 8), rcx);
+    __ movl(Address(rsi,12), rdx);
+
     //
     // Extended cpuid(0x80000005)
     //
@@ -365,7 +379,7 @@ void VM_Version::get_processor_features() {
   }
 
   char buf[256];
-  jio_snprintf(buf, sizeof(buf), "(%u cores per cpu, %u threads per core) family %d model %d stepping %d%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s",
+  jio_snprintf(buf, sizeof(buf), "(%u cores per cpu, %u threads per core) family %d model %d stepping %d%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s",
                cores_per_cpu(), threads_per_core(),
                cpu_family(), _model, _stepping,
                (supports_cmov() ? ", cmov" : ""),
@@ -383,7 +397,10 @@ void VM_Version::get_processor_features() {
                (supports_3dnow_prefetch() ? ", 3dnowpref" : ""),
                (supports_lzcnt()   ? ", lzcnt": ""),
                (supports_sse4a()   ? ", sse4a": ""),
-               (supports_ht() ? ", ht": ""));
+               (supports_ht() ? ", ht": ""),
+               (supports_tsc() ? ", tsc": ""),
+               (supports_tscinv_bit() ? ", tscinvbit": ""),
+               (supports_tscinv() ? ", tscinv": ""));
   _features_str = strdup(buf);
 
   // UseSSE is set to the smaller of what hardware supports and what

src/cpu/x86/vm/vm_version_x86.hpp

 /*
- * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -176,6 +176,15 @@ public:
     } bits;
   };
 
+  union ExtCpuid7Edx {
+    uint32_t value;
+    struct {
+      uint32_t               : 8,
+              tsc_invariance : 1,
+                             : 23;
+    } bits;
+  };
+
 protected:
   static int _cpu;
   static int _model;
@@ -200,9 +209,22 @@ protected:
     CPU_SSE4_1 = (1 << 11),
     CPU_SSE4_2 = (1 << 12),
     CPU_POPCNT = (1 << 13),
-     CPU_LZCNT  = (1 << 14)
+    CPU_LZCNT  = (1 << 14),
+    CPU_TSC    = (1 << 15),
+    CPU_TSCINV = (1 << 16)
   } cpuFeatureFlags;
 
+  enum {
+    // AMD
+    CPU_FAMILY_AMD_11H       = 17,
+    // Intel
+    CPU_FAMILY_INTEL_CORE    = 6,
+    CPU_MODEL_NEHALEM_EP     = 26,
+    CPU_MODEL_WESTMERE_EP    = 44,
+//  CPU_MODEL_IVYBRIDGE_EP   = ??, TODO - get real value
+    CPU_MODEL_SANDYBRIDGE_EP = 45
+  } cpuExtendedFamily;
+
   // cpuid information block.  All info derived from executing cpuid with
   // various function numbers is stored here.  Intel and AMD info is
   // merged in this block: accessor methods disentangle it.
@@ -270,6 +292,12 @@ protected:
     ExtCpuid5Ex  ext_cpuid5_ecx; // L1 data cache info (AMD)
     ExtCpuid5Ex  ext_cpuid5_edx; // L1 instruction cache info (AMD)
 
+    // cpuid function 0x80000007
+    uint32_t     ext_cpuid7_eax; // reserved
+    uint32_t     ext_cpuid7_ebx; // reserved
+    uint32_t     ext_cpuid7_ecx; // reserved
+    ExtCpuid7Edx ext_cpuid7_edx; // tscinv
+
     // cpuid function 0x80000008
     uint32_t     ext_cpuid8_eax; // unused currently
     uint32_t     ext_cpuid8_ebx; // reserved
@@ -286,19 +314,23 @@ protected:
     result += _cpuid_info.std_cpuid1_eax.bits.ext_family;
     return result;
   }
+
   static uint32_t extended_cpu_model() {
     uint32_t result = _cpuid_info.std_cpuid1_eax.bits.model;
     result |= _cpuid_info.std_cpuid1_eax.bits.ext_model << 4;
     return result;
   }
+
   static uint32_t cpu_stepping() {
     uint32_t result = _cpuid_info.std_cpuid1_eax.bits.stepping;
     return result;
   }
+
   static uint logical_processor_count() {
     uint result = threads_per_core();
     return result;
   }
+
   static uint32_t feature_flags() {
     uint32_t result = 0;
     if (_cpuid_info.std_cpuid1_edx.bits.cmpxchg8 != 0)
@@ -328,6 +360,10 @@ protected:
       result |= CPU_SSE4_2;
     if (_cpuid_info.std_cpuid1_ecx.bits.popcnt != 0)
       result |= CPU_POPCNT;
+    if (_cpuid_info.std_cpuid1_edx.bits.tsc != 0)
+      result |= CPU_TSC;
+    if (_cpuid_info.ext_cpuid7_edx.bits.tsc_invariance != 0)
+      result |= CPU_TSCINV;
 
     // AMD features.
     if (is_amd()) {
@@ -352,6 +388,7 @@ public:
   static ByteSize dcp_cpuid4_offset() { return byte_offset_of(CpuidInfo, dcp_cpuid4_eax); }
   static ByteSize ext_cpuid1_offset() { return byte_offset_of(CpuidInfo, ext_cpuid1_eax); }
   static ByteSize ext_cpuid5_offset() { return byte_offset_of(CpuidInfo, ext_cpuid5_eax); }
+  static ByteSize ext_cpuid7_offset() { return byte_offset_of(CpuidInfo, ext_cpuid7_eax); }
   static ByteSize ext_cpuid8_offset() { return byte_offset_of(CpuidInfo, ext_cpuid8_eax); }
   static ByteSize tpl_cpuidB0_offset() { return byte_offset_of(CpuidInfo, tpl_cpuidB0_eax); }
   static ByteSize tpl_cpuidB1_offset() { return byte_offset_of(CpuidInfo, tpl_cpuidB1_eax); }
@@ -382,7 +419,6 @@ public:
   //
   static int  cpu_family()        { return _cpu;}
   static bool is_P6()             { return cpu_family() >= 6; }
-
   static bool is_amd()            { assert_is_initialized(); return _cpuid_info.std_vendor_name_0 == 0x68747541; } // 'htuA'
   static bool is_intel()          { assert_is_initialized(); return _cpuid_info.std_vendor_name_0 == 0x756e6547; } // 'uneG'
 
@@ -447,14 +483,49 @@ public:
   static bool supports_sse4_1()   { return (_cpuFeatures & CPU_SSE4_1) != 0; }
   static bool supports_sse4_2()   { return (_cpuFeatures & CPU_SSE4_2) != 0; }
   static bool supports_popcnt()   { return (_cpuFeatures & CPU_POPCNT) != 0; }
-  //
+  static bool supports_tsc()      { return (_cpuFeatures & CPU_TSC)    != 0; }
+
+  // Intel features
+  static bool is_intel_family_core() { return is_intel() &&
+                                       extended_cpu_family() == CPU_FAMILY_INTEL_CORE; }
+
+  static bool is_intel_tsc_synched_at_init()  {
+    if (is_intel_family_core()) {
+      uint32_t ext_model = extended_cpu_model();
+      if (ext_model == CPU_MODEL_NEHALEM_EP   ||
+          ext_model == CPU_MODEL_WESTMERE_EP  ||
+// TODO   ext_model == CPU_MODEL_IVYBRIDGE_EP ||
+          ext_model == CPU_MODEL_SANDYBRIDGE_EP) {
+        // 2-socket invtsc support. EX versions with 4 sockets are not
+        // guaranteed to synchronize tscs at initialization via a double
+        // handshake. The tscs can be explicitly set in software.  Code
+        // that uses tsc values must be prepared for them to arbitrarily
+        // jump backward or forward.
+        return true;
+      }
+    }
+    return false;
+  }
+
   // AMD features
-  //
   static bool supports_3dnow_prefetch()    { return (_cpuFeatures & CPU_3DNOW_PREFETCH) != 0; }
   static bool supports_mmx_ext()  { return is_amd() && _cpuid_info.ext_cpuid1_edx.bits.mmx_amd != 0; }
   static bool supports_lzcnt()    { return (_cpuFeatures & CPU_LZCNT) != 0; }
   static bool supports_sse4a()    { return (_cpuFeatures & CPU_SSE4A) != 0; }
 
+  static bool is_amd_Barcelona()  { return is_amd() &&
+                                           extended_cpu_family() == CPU_FAMILY_AMD_11H; }
+
+  // Intel and AMD newer cores support fast timestamps well
+  static bool supports_tscinv_bit() {
+    return (_cpuFeatures & CPU_TSCINV) != 0;
+  }
+  static bool supports_tscinv() {
+    return supports_tscinv_bit() &&
+           ( (is_amd() && !is_amd_Barcelona()) ||
+             is_intel_tsc_synched_at_init() );
+  }
+
   // Intel Core and newer cpus have fast IDIV instruction (excluding Atom).
   static bool has_fast_idiv()     { return is_intel() && cpu_family() == 6 &&
                                            supports_sse3() && _model != 0x1C; }

src/os_cpu/bsd_x86/vm/os_bsd_x86.hpp

@@ -28,6 +28,8 @@
   static void setup_fpu();
   static bool supports_sse();
 
+  static jlong rdtsc();
+
   static bool is_allocatable(size_t bytes);
 
   // Used to register dynamic code cache area with the OS

src/os_cpu/bsd_x86/vm/os_bsd_x86.inline.hpp

+/*
+ * Copyright (c) 2011, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#ifndef OS_CPU_BSD_X86_VM_OS_BSD_X86_INLINE_HPP
+#define OS_CPU_BSD_X86_VM_OS_BSD_X86_INLINE_HPP
+
+#include "runtime/os.hpp"
+
+// See http://www.technovelty.org/code/c/reading-rdtsc.htl for details
+inline jlong os::rdtsc() {
+#ifndef AMD64
+  // 64 bit result in edx:eax
+  uint64_t res;
+  __asm__ __volatile__ ("rdtsc" : "=A" (res));
+  return (jlong)res;
+#else
+  uint64_t res;
+  uint32_t ts1, ts2;
+  __asm__ __volatile__ ("rdtsc" : "=a" (ts1), "=d" (ts2));
+  res = ((uint64_t)ts1 | (uint64_t)ts2 << 32);
+  return (jlong)res;
+#endif // AMD64
+}
+
+#endif // OS_CPU_BSD_X86_VM_OS_BSD_X86_INLINE_HPP

src/os_cpu/linux_x86/vm/os_linux_x86.hpp

 /*
- * Copyright (c) 1999, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1999, 2011, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -28,6 +28,8 @@
   static void setup_fpu();
   static bool supports_sse();
 
+  static jlong rdtsc();
+
   static bool is_allocatable(size_t bytes);
 
   // Used to register dynamic code cache area with the OS

src/os_cpu/linux_x86/vm/os_linux_x86.inline.hpp

+/*
+ * Copyright (c) 2011, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#ifndef OS_CPU_LINUX_X86_VM_OS_LINUX_X86_INLINE_HPP
+#define OS_CPU_LINUX_X86_VM_OS_LINUX_X86_INLINE_HPP
+
+#include "runtime/os.hpp"
+
+// See http://www.technovelty.org/code/c/reading-rdtsc.htl for details
+inline jlong os::rdtsc() {
+#ifndef AMD64
+  // 64 bit result in edx:eax
+  uint64_t res;
+  __asm__ __volatile__ ("rdtsc" : "=A" (res));
+  return (jlong)res;
+#else
+  uint64_t res;
+  uint32_t ts1, ts2;
+  __asm__ __volatile__ ("rdtsc" : "=a" (ts1), "=d" (ts2));
+  res = ((uint64_t)ts1 | (uint64_t)ts2 << 32);
+  return (jlong)res;
+#endif // AMD64
+}
+
+#endif // OS_CPU_LINUX_X86_VM_OS_LINUX_X86_INLINE_HPP

src/os_cpu/solaris_x86/vm/os_solaris_x86.hpp

@@ -46,6 +46,8 @@
 
   static bool supports_sse();
 
+  static jlong rdtsc();
+
   static bool is_allocatable(size_t bytes);
 
   // Used to register dynamic code cache area with the OS

src/os_cpu/solaris_x86/vm/os_solaris_x86.inline.hpp

+/*
+ * Copyright (c) 2011, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#ifndef OS_CPU_SOLARIS_X86_VM_OS_SOLARIS_X86_INLINE_HPP
+#define OS_CPU_SOLARIS_X86_VM_OS_SOLARIS_X86_INLINE_HPP
+
+#include "runtime/os.hpp"
+
+inline jlong os::rdtsc() { return _raw_rdtsc(); }
+
+#endif // OS_CPU_SOLARIS_X86_VM_OS_SOLARIS_X86_INLINE_HPP

src/os_cpu/solaris_x86/vm/solaris_x86_32.il

@@ -43,6 +43,11 @@
       movl     %ebp, %eax 
       .end
 
+  // Support for os::rdtsc()
+      .inline _raw_rdtsc,0
+      rdtsc
+      .end
+
   // Support for jint Atomic::add(jint inc, volatile jint* dest)
   // An additional bool (os::is_MP()) is passed as the last argument.
       .inline _Atomic_add,3
@@ -113,7 +118,6 @@
       fistpll   (%eax)
       .end
 
-
   // Support for OrderAccess::acquire()
       .inline _OrderAccess_acquire,0
       movl     0(%esp), %eax

src/os_cpu/solaris_x86/vm/solaris_x86_64.il

@@ -30,12 +30,19 @@
       movq     %fs:0, %rax 
       .end
 
-  // Get the frame pointer from current frame.
+  // Get current fp
       .inline _get_current_fp,0
       .volatile
       movq     %rbp, %rax 
       .end
 
+  // Support for os::rdtsc()
+      .inline _raw_rdtsc,0
+      rdtsc
+      salq     $32, %rdx
+      orq      %rdx, %rax
+      .end
+
   // Support for jint Atomic::add(jint add_value, volatile jint* dest)
       .inline _Atomic_add,2
       movl     %edi, %eax      // save add_value for return

src/os_cpu/windows_x86/vm/os_windows_x86.hpp

@@ -58,6 +58,8 @@
   static void setup_fpu();
   static bool supports_sse() { return true; }
 
+  static jlong rdtsc();
+
   static bool      register_code_area(char *low, char *high);
 
 #endif // OS_CPU_WINDOWS_X86_VM_OS_WINDOWS_X86_HPP

src/os_cpu/windows_x86/vm/os_windows_x86.inline.hpp

+/*
+ * Copyright (c) 2011, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#ifndef OS_CPU_WINDOWS_X86_VM_OS_WINDOWS_X86_INLINE_HPP
+#define OS_CPU_WINDOWS_X86_VM_OS_WINDOWS_X86_INLINE_HPP
+
+#include "runtime/os.hpp"
+
+inline jlong os::rdtsc() {
+  // 32 bit: 64 bit result in edx:eax
+  // 64 bit: 64 bit value in rax
+  uint64_t res;
+  res = (uint64_t)__rdtsc();
+  return (jlong)res;
+}
+
+#endif // OS_CPU_WINDOWS_X86_VM_OS_WINDOWS_X86_INLINE_HPP

src/share/vm/runtime/init.cpp

 /*
- * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -47,15 +47,16 @@ void bytecodes_init();
 void classLoader_init();
 void codeCache_init();
 void VM_Version_init();
+void os_init_globals();        // depends on VM_Version_init, before universe_init
 void stubRoutines_init1();
-jint universe_init();  // dependent on codeCache_init and stubRoutines_init
+jint universe_init();          // depends on codeCache_init and stubRoutines_init
 void interpreter_init();       // before any methods loaded
 void invocationCounter_init(); // before any methods loaded
 void marksweep_init();
 void accessFlags_init();
 void templateTable_init();
 void InterfaceSupport_init();
-void universe2_init();  // dependent on codeCache_init and stubRoutines_init
+void universe2_init();  // dependent on codeCache_init and stubRoutines_init, loads primordial classes
 void referenceProcessor_init();
 void jni_handles_init();
 void vmStructs_init();
@@ -94,8 +95,10 @@ jint init_globals() {
   classLoader_init();
   codeCache_init();
   VM_Version_init();
+  os_init_globals();
   stubRoutines_init1();
-  jint status = universe_init();  // dependent on codeCache_init and stubRoutines_init
+  jint status = universe_init();  // dependent on codeCache_init and
+                                  // stubRoutines_init1
   if (status != JNI_OK)
     return status;
 
@@ -106,7 +109,7 @@ jint init_globals() {
   templateTable_init();
   InterfaceSupport_init();
   SharedRuntime::generate_stubs();
-  universe2_init();  // dependent on codeCache_init and stubRoutines_init
+  universe2_init();  // dependent on codeCache_init and stubRoutines_init1
   referenceProcessor_init();
   jni_handles_init();
 #ifndef VM_STRUCTS_KERNEL

src/share/vm/runtime/os.cpp

@@ -82,6 +82,12 @@ julong os::num_frees = 0;           // # of calls to free
 julong os::free_bytes = 0;          // # of bytes freed
 #endif
 
+void os_init_globals() {
+  // Called from init_globals().
+  // See Threads::create_vm() in thread.cpp, and init.cpp.
+  os::init_globals();
+}
+
 // Fill in buffer with current local time as an ISO-8601 string.
 // E.g., yyyy-mm-ddThh:mm:ss-zzzz.
 // Returns buffer, or NULL if it failed.

src/share/vm/runtime/os.hpp

@@ -99,9 +99,11 @@ class os: AllStatic {
   }
 
  public:
-
   static void init(void);                      // Called before command line parsing
   static jint init_2(void);                    // Called after command line parsing
+  static void init_globals(void) {             // Called from init_globals() in init.cpp
+    init_globals_ext();
+  }
   static void init_3(void);                    // Called at the end of vm init
 
   // File names are case-insensitive on windows only
@@ -671,6 +673,11 @@ class os: AllStatic {
   // rest of line is skipped. Returns number of bytes read or -1 on EOF
   static int get_line_chars(int fd, char *buf, const size_t bsize);
 
+  // Extensions
+#include "runtime/os_ext.hpp"
+
+ public:
+
   // Platform dependent stuff
 #ifdef TARGET_OS_FAMILY_linux
 # include "os_linux.hpp"
@@ -715,6 +722,7 @@ class os: AllStatic {
 # include "os_bsd_zero.hpp"
 #endif
 
+ public:
   // debugging support (mostly used by debug.cpp but also fatal error handler)
   static bool find(address pc, outputStream* st = tty); // OS specific function to make sense out of an address
 

src/share/vm/runtime/os_ext.hpp

+/*
+ * Copyright (c) 2011 Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#ifndef SHARE_VM_RUNTIME_OS_EXT_HPP
+#define SHARE_VM_RUNTIME_OS_EXT_HPP
+
+ public:
+  static void init_globals_ext() {} // Run from init_globals().
+                                    // See os.hpp/cpp and init.cpp.
+
+ private:
+
+#endif // SHARE_VM_RUNTIME_OS_EXT_HPP