6880034: SIGBUS during deoptimisation at a safepoint on 64bit-SPARC

Summary: Fix problem with the double register encodings in sparc.ad
Reviewed-by: never, jrose
Contributed-by: volker.simonis@gmail.com

src/cpu/sparc/vm/sharedRuntime_sparc.cpp

@@ -107,7 +107,7 @@ OopMap* RegisterSaver::save_live_registers(MacroAssembler* masm, int additional_
   // are saved in register windows - I's and L's in the caller's frame and O's in the stub frame
   // (as the stub's I's) when the runtime routine called by the stub creates its frame.
   int i;
-  // Always make the frame size 16 bytr aligned.
+  // Always make the frame size 16 byte aligned.
   int frame_size = round_to(additional_frame_words + register_save_size, 16);
   // OopMap frame size is in c2 stack slots (sizeof(jint)) not bytes or words
   int frame_size_in_slots = frame_size / sizeof(jint);
@@ -201,15 +201,14 @@ OopMap* RegisterSaver::save_live_registers(MacroAssembler* masm, int additional_
   __ stx(G5, SP, ccr_offset+STACK_BIAS);
   __ stxfsr(SP, fsr_offset+STACK_BIAS);
 
-  // Save all the FP registers
+  // Save all the FP registers: 32 doubles (32 floats correspond to the 2 halves of the first 16 doubles)
   int offset = d00_offset;
-  for( int i=0; i<64; i+=2 ) {
+  for( int i=0; i<FloatRegisterImpl::number_of_registers; i+=2 ) {
     FloatRegister f = as_FloatRegister(i);
     __ stf(FloatRegisterImpl::D,  f, SP, offset+STACK_BIAS);
+    // Record as callee saved both halves of double registers (2 float registers).
     map->set_callee_saved(VMRegImpl::stack2reg(offset>>2), f->as_VMReg());
-    if (true) {
     map->set_callee_saved(VMRegImpl::stack2reg((offset + sizeof(float))>>2), f->as_VMReg()->next());
-    }
     offset += sizeof(double);
   }
 
@@ -224,7 +223,7 @@ OopMap* RegisterSaver::save_live_registers(MacroAssembler* masm, int additional_
 void RegisterSaver::restore_live_registers(MacroAssembler* masm) {
 
   // Restore all the FP registers
-  for( int i=0; i<64; i+=2 ) {
+  for( int i=0; i<FloatRegisterImpl::number_of_registers; i+=2 ) {
     __ ldf(FloatRegisterImpl::D, SP, d00_offset+i*sizeof(float)+STACK_BIAS, as_FloatRegister(i));
   }
 

src/cpu/sparc/vm/sparc.ad

@@ -193,38 +193,38 @@ reg_def R_F31( SOC, SOC, Op_RegF, 31, F31->as_VMReg());
 // I believe we can't handle callee-save doubles D32 and up until
 // the place in the sparc stack crawler that asserts on the 255 is
 // fixed up.
-reg_def R_D32x(SOC, SOC, Op_RegD,255, F32->as_VMReg());
-reg_def R_D32 (SOC, SOC, Op_RegD,  1, F32->as_VMReg()->next());
-reg_def R_D34x(SOC, SOC, Op_RegD,255, F34->as_VMReg());
-reg_def R_D34 (SOC, SOC, Op_RegD,  3, F34->as_VMReg()->next());
-reg_def R_D36x(SOC, SOC, Op_RegD,255, F36->as_VMReg());
-reg_def R_D36 (SOC, SOC, Op_RegD,  5, F36->as_VMReg()->next());
-reg_def R_D38x(SOC, SOC, Op_RegD,255, F38->as_VMReg());
-reg_def R_D38 (SOC, SOC, Op_RegD,  7, F38->as_VMReg()->next());
-reg_def R_D40x(SOC, SOC, Op_RegD,255, F40->as_VMReg());
-reg_def R_D40 (SOC, SOC, Op_RegD,  9, F40->as_VMReg()->next());
-reg_def R_D42x(SOC, SOC, Op_RegD,255, F42->as_VMReg());
-reg_def R_D42 (SOC, SOC, Op_RegD, 11, F42->as_VMReg()->next());
-reg_def R_D44x(SOC, SOC, Op_RegD,255, F44->as_VMReg());
-reg_def R_D44 (SOC, SOC, Op_RegD, 13, F44->as_VMReg()->next());
-reg_def R_D46x(SOC, SOC, Op_RegD,255, F46->as_VMReg());
-reg_def R_D46 (SOC, SOC, Op_RegD, 15, F46->as_VMReg()->next());
-reg_def R_D48x(SOC, SOC, Op_RegD,255, F48->as_VMReg());
-reg_def R_D48 (SOC, SOC, Op_RegD, 17, F48->as_VMReg()->next());
-reg_def R_D50x(SOC, SOC, Op_RegD,255, F50->as_VMReg());
-reg_def R_D50 (SOC, SOC, Op_RegD, 19, F50->as_VMReg()->next());
-reg_def R_D52x(SOC, SOC, Op_RegD,255, F52->as_VMReg());
-reg_def R_D52 (SOC, SOC, Op_RegD, 21, F52->as_VMReg()->next());
-reg_def R_D54x(SOC, SOC, Op_RegD,255, F54->as_VMReg());
-reg_def R_D54 (SOC, SOC, Op_RegD, 23, F54->as_VMReg()->next());
-reg_def R_D56x(SOC, SOC, Op_RegD,255, F56->as_VMReg());
-reg_def R_D56 (SOC, SOC, Op_RegD, 25, F56->as_VMReg()->next());
-reg_def R_D58x(SOC, SOC, Op_RegD,255, F58->as_VMReg());
-reg_def R_D58 (SOC, SOC, Op_RegD, 27, F58->as_VMReg()->next());
-reg_def R_D60x(SOC, SOC, Op_RegD,255, F60->as_VMReg());
-reg_def R_D60 (SOC, SOC, Op_RegD, 29, F60->as_VMReg()->next());
-reg_def R_D62x(SOC, SOC, Op_RegD,255, F62->as_VMReg());
-reg_def R_D62 (SOC, SOC, Op_RegD, 31, F62->as_VMReg()->next());
+reg_def R_D32 (SOC, SOC, Op_RegD,  1, F32->as_VMReg());
+reg_def R_D32x(SOC, SOC, Op_RegD,255, F32->as_VMReg()->next());
+reg_def R_D34 (SOC, SOC, Op_RegD,  3, F34->as_VMReg());
+reg_def R_D34x(SOC, SOC, Op_RegD,255, F34->as_VMReg()->next());
+reg_def R_D36 (SOC, SOC, Op_RegD,  5, F36->as_VMReg());
+reg_def R_D36x(SOC, SOC, Op_RegD,255, F36->as_VMReg()->next());
+reg_def R_D38 (SOC, SOC, Op_RegD,  7, F38->as_VMReg());
+reg_def R_D38x(SOC, SOC, Op_RegD,255, F38->as_VMReg()->next());
+reg_def R_D40 (SOC, SOC, Op_RegD,  9, F40->as_VMReg());
+reg_def R_D40x(SOC, SOC, Op_RegD,255, F40->as_VMReg()->next());
+reg_def R_D42 (SOC, SOC, Op_RegD, 11, F42->as_VMReg());
+reg_def R_D42x(SOC, SOC, Op_RegD,255, F42->as_VMReg()->next());
+reg_def R_D44 (SOC, SOC, Op_RegD, 13, F44->as_VMReg());
+reg_def R_D44x(SOC, SOC, Op_RegD,255, F44->as_VMReg()->next());
+reg_def R_D46 (SOC, SOC, Op_RegD, 15, F46->as_VMReg());
+reg_def R_D46x(SOC, SOC, Op_RegD,255, F46->as_VMReg()->next());
+reg_def R_D48 (SOC, SOC, Op_RegD, 17, F48->as_VMReg());
+reg_def R_D48x(SOC, SOC, Op_RegD,255, F48->as_VMReg()->next());
+reg_def R_D50 (SOC, SOC, Op_RegD, 19, F50->as_VMReg());
+reg_def R_D50x(SOC, SOC, Op_RegD,255, F50->as_VMReg()->next());
+reg_def R_D52 (SOC, SOC, Op_RegD, 21, F52->as_VMReg());
+reg_def R_D52x(SOC, SOC, Op_RegD,255, F52->as_VMReg()->next());
+reg_def R_D54 (SOC, SOC, Op_RegD, 23, F54->as_VMReg());
+reg_def R_D54x(SOC, SOC, Op_RegD,255, F54->as_VMReg()->next());
+reg_def R_D56 (SOC, SOC, Op_RegD, 25, F56->as_VMReg());
+reg_def R_D56x(SOC, SOC, Op_RegD,255, F56->as_VMReg()->next());
+reg_def R_D58 (SOC, SOC, Op_RegD, 27, F58->as_VMReg());
+reg_def R_D58x(SOC, SOC, Op_RegD,255, F58->as_VMReg()->next());
+reg_def R_D60 (SOC, SOC, Op_RegD, 29, F60->as_VMReg());
+reg_def R_D60x(SOC, SOC, Op_RegD,255, F60->as_VMReg()->next());
+reg_def R_D62 (SOC, SOC, Op_RegD, 31, F62->as_VMReg());
+reg_def R_D62x(SOC, SOC, Op_RegD,255, F62->as_VMReg()->next());
 
 
 // ----------------------------

test/compiler/6880034/Test6880034.java

+/*
+ * Copyright 2009 SAP AG.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+/**
+ * @test
+ * @bug 6880034
+ * @summary SIGBUS during deoptimisation at a safepoint on 64bit-SPARC
+ *
+ * @run main/othervm -Xcomp -Xbatch -XX:CompileCommand=compileonly,Test6880034,deopt_compiledframe_at_safepoint -XX:+PrintCompilation Test6880034
+ */
+
+
+
+// This test provokes a deoptimisation at a safepoint.
+//
+// It achieves this by compiling the method 'deopt_compiledframe_at_safepoint'
+// before its first usage at a point in time when a call to the virtual method
+// A::doSomething() from within 'deopt_compiledframe_at_safepoint' can be
+// optimised to a static call because class A has no descendants.
+//
+// Later, when deopt_compiledframe_at_safepoint() is running, class B which
+// extends A and overrides the virtual method "doSomething()", is loaded
+// asynchronously in another thread.  This makes the compiled code of
+// 'deopt_compiledframe_at_safepoint' invalid and triggers a deoptimisation of
+// the frame where 'deopt_compiledframe_at_safepoint' is running in a
+// loop.
+//
+// The deoptimisation leads to a SIGBUS on 64-bit server VMs on SPARC and to
+// an incorrect result on 32-bit server VMs on SPARC due to a regression
+// introduced by the change: "6420645: Create a vm that uses compressed oops
+// for up to 32gb heapsizes"
+// (http://hg.openjdk.java.net/jdk7/jdk7/hotspot/rev/ba764ed4b6f2).  Further
+// investigation showed that change 6420645 is not really the root cause of
+// this error but only reveals a problem with the float register encodings in
+// sparc.ad which was hidden until now.
+//
+// Notice that for this test to fail in jtreg it is crucial that
+// deopt_compiledframe_at_safepoint() runs in the main thread. Otherwise a
+// crash in deopt_compiledframe_at_safepoint() will not be detected as a test
+// failure by jtreg.
+//
+// Author: Volker H. Simonis
+
+class A {
+  public int doSomething() {
+    return 0;
+  }
+}
+
+class B extends A {
+  public B() {}
+  // override 'A::doSomething()'
+  public int doSomething() {
+    return 1;
+  }
+}
+
+class G {
+  public static volatile A a = new A();
+
+  // Change 'a' to point to a 'B' object
+  public static void setAtoB() {
+    try {
+      a =  (A) ClassLoader.
+        getSystemClassLoader().
+        loadClass("B").
+        getConstructor(new Class[] {}).
+        newInstance(new Object[] {});
+    }
+    catch (Exception e) {
+      System.out.println(e);
+    }
+  }
+}
+
+public class Test6880034 {
+
+  public static volatile boolean is_in_loop = false;
+  public static volatile boolean stop_while_loop = false;
+
+  public static double deopt_compiledframe_at_safepoint() {
+    // This will be an optimised static call to A::doSomething() until we load "B"
+    int i = G.a.doSomething();
+
+    // Need more than 16 'double' locals in this frame
+    double local1 = 1;
+    double local2 = 2;
+    double local3 = 3;
+    double local4 = 4;
+    double local5 = 5;
+    double local6 = 6;
+    double local7 = 7;
+    double local8 = 8;
+
+    long k = 0;
+    // Once we load "B", this method will be made 'not entrant' and deoptimised
+    // at the safepoint which is at the end of this loop.
+    while (!stop_while_loop) {
+      if (k ==  1) local1 += i;
+      if (k ==  2) local2 += i;
+      if (k ==  3) local3 += i;
+      if (k ==  4) local4 += i;
+      if (k ==  5) local5 += i;
+      if (k ==  6) local6 += i;
+      if (k ==  7) local7 += i;
+      if (k ==  8) local8 += i;
+
+      // Tell the world that we're now running wild in the loop
+      if (k++ == 20000) is_in_loop = true;
+    }
+
+    return
+      local1 + local2 + local3 + local4 +
+      local5 + local6 + local7 + local8 + i;
+  }
+
+  public static void main(String[] args) {
+
+    // Just to resolve G before we compile deopt_compiledframe_at_safepoint()
+    G g = new G();
+
+    // Asynchronous thread which will eventually invalidate the code for
+    // deopt_compiledframe_at_safepoint() and therefore triggering a
+    // deoptimisation of that method.
+    new Thread() {
+      public void run() {
+        while (!is_in_loop) {
+          // Wait until the loop is running
+        }
+        // Load class 'B' asynchronously..
+        G.setAtoB();
+        // ..and stop the loop
+        stop_while_loop = true;
+      }
+    }.start();
+
+    // Run the loop in deopt_compiledframe_at_safepoint()
+    double retVal = deopt_compiledframe_at_safepoint();
+
+    System.out.println(retVal == 36 ? "OK" : "ERROR : " + retVal);
+    if (retVal != 36) throw new RuntimeException();
+  }
+}