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From ge...@apache.org
Subject svn commit: r429034 [1/4] - in /incubator/harmony/standard/site: docs/subcomponents/drlvm/ xdocs/subcomponents/drlvm/
Date Sat, 05 Aug 2006 19:10:28 GMT
Author: geirm
Date: Sat Aug  5 12:10:27 2006
New Revision: 429034

URL: http://svn.apache.org/viewvc?rev=429034&view=rev
Log:
HARMONY-951

Docs on how to write a GC for DRLVM


Added:
    incubator/harmony/standard/site/docs/subcomponents/drlvm/gc-howto.html
    incubator/harmony/standard/site/xdocs/subcomponents/drlvm/gc-howto-content.html   (with props)
    incubator/harmony/standard/site/xdocs/subcomponents/drlvm/gc-howto.xml   (with props)
Modified:
    incubator/harmony/standard/site/docs/subcomponents/drlvm/debugging_VM_and_JIT.html
    incubator/harmony/standard/site/docs/subcomponents/drlvm/developers_guide.html
    incubator/harmony/standard/site/docs/subcomponents/drlvm/index.html
    incubator/harmony/standard/site/xdocs/subcomponents/drlvm/debugging_VM_and_JIT.xml   (contents, props changed)
    incubator/harmony/standard/site/xdocs/subcomponents/drlvm/getting_started.xml   (props changed)
    incubator/harmony/standard/site/xdocs/subcomponents/drlvm/index.xml   (contents, props changed)

Modified: incubator/harmony/standard/site/docs/subcomponents/drlvm/debugging_VM_and_JIT.html
URL: http://svn.apache.org/viewvc/incubator/harmony/standard/site/docs/subcomponents/drlvm/debugging_VM_and_JIT.html?rev=429034&r1=429033&r2=429034&view=diff
==============================================================================
--- incubator/harmony/standard/site/docs/subcomponents/drlvm/debugging_VM_and_JIT.html (original)
+++ incubator/harmony/standard/site/docs/subcomponents/drlvm/debugging_VM_and_JIT.html Sat Aug  5 12:10:27 2006
@@ -206,943 +206,943 @@
                     <td width="80%" align="left" valign="top">
                                         
                                                                 <div>
-<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
-<html>
-   <head>
-      <meta http-equiv="Content-Type" content=
-      "text/html; charset=windows-1251">
-      <title>
-         Debugging DRL Virtual Machine and JIT Compiler
-      </title>
-   </head>
-   <body>
-      <h1>
-         <a name="top"></a>Debugging the DRL Virtual Machine and the
-         JIT Compiler
-      </h1>
-      <p>
-         This document gives practical instructions on how to debug
-         the DRL virtual machine and its baseline just-in-time
-         compiler Jitrino.JET. For a definition of components and
-         details on their internal structure, consult the <i>DRL
-         Virtual Machine Developer&rsquo;s Guide</i> supplied with
-         the DRLVM image.
-      </p>
-      <p>
-         The document includes two groups of debugging tips, one for
-         VM tips, and the other for JIT compiler tips, as shown
-         below.
-      </p>
-      <p>
-         <a href="#Disclaimer">Disclaimer and Legal Information</a>
-      </p>
-      <p>
-         <a href="#Debugging_VM">Debugging the Virtual Machine</a>
-      </p>
-      <blockquote>
-         <p>
-            <a href="#How_to_debug_VM">How to debug the VM?</a>
-         </p>
-         <p>
-            <a href="#Extended_Debug_VM">How to get more of your
-            debugging?</a>
-         </p>
-      </blockquote>
-      <p>
-         <a href="#Debugging_JIT">Debugging the Jitrino.JET Baseline
-         Compiler</a>
-      </p>
-      <blockquote>
-         <p>
-            <a href="#Enable_Tracing">How to enable tracing in
-            Jitrino.JET?</a>
-         </p>
-         <p>
-            <a href="#Config_Trace_Logging">How to configure trace
-            logging?</a>
-         </p>
-         <p>
-            <a href="#Extend_Trace_JIT">How to get more of your
-            tracing?</a>
-         </p>
-      </blockquote>
-      <h1>
-         <a name="Disclaimer">Disclaimer and Legal Information</a>
-      </h1>
-      <p>
-         Copyright 2006 The Apache Software Foundation or its
-         licensors, as applicable.
-      </p>
-      <p>
-         Licensed under the Apache License, Version 2.0 (the
-         License); you may not use this file except in compliance
-         with the License. You may obtain a copy of the License at <a
-         href="http://www.apache.org/licenses/LICENSE-2.0" target= 
-         "_blank">http://www.apache.org/licenses/LICENSE-2.0</a>.
-      </p>
-      <p>
-         Unless required by applicable law or agreed to in writing,
-         software distributed under the License is distributed on an
-         AS IS BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
-         either express or implied. See the License for the specific
-         language governing permissions and limitations under the
-         License.
-      </p>
-      <p>
-         <a href="#top">Back to top</a>
-      </p>
-      <h1>
-         <a name="Debugging_VM">Debugging the Virtual Machine</a>
-      </h1>
-      <p>
-         This section gives an insight into debugging the DRL virtual
-         machine version 1.0 and provides tips on resolving
-         non-standard debugging issues.
-      </p>
-      <h2>
-         <a name="How_to_debug_VM">How to debug the VM?</a>
-      </h2>
-      <p>
-         This section gives instructions on different scenarios of
-         debugging the VM source code.
-      </p>
-      <h3>
-         Basic Debugging Steps
-      </h3>
-      <p>
-         For ordinary tests, start the ij executable with the
-         debugger enabled, as follows:
-      </p>
-      <p>
-         <strong>On Windows<a href="#*">*</a></strong>
-      </p>
-      <ol>
-         <li>
-            Start Microsoft Visual Studio<a href="#*">*</a> and open
-            the solution file <code>vm\build\vm.sln</code>.
-         </li>
-         <li>
-            Open the source code that you need to debug, set
-            breakpoints and perform all other preliminary steps.
-         </li>
-         <li>
-            Select the vmcore project and open its properties to
-            specify the location of the <code>ij</code> executable.
-            Select the <strong>Debugging</strong> tab and specify the
-            command and command arguments.
-         </li>
-         <li>
-            Copy the ZLib tool library <code>zlib1.dll</code> to the
-            location of the VM executable.
-         </li>
-         <li>
-            Start debugging via the menu <strong>Debug</strong> &gt;
-            <strong>Start</strong>, click <strong>NO</strong> in the
-            popup dialog offering to build the project.
-         </li>
-      </ol>
-      <p>
-         <strong>On Linux<a href="#*">*</a></strong>
-      </p>
-      <ol>
-         <li>
-            Set up the <code>LD_LIBRARY_PATH</code> to point to the
-            <code>deploy/jre/bin</code> directory. Change the working
-            directory to the location of the VM executable and run: 
-<pre>
-gdb ij
-</pre>
-         </li>
-         <li>
-            Set breakpoints and perform all other preliminary steps.
-         </li>
-         <li>
-            On the command line, specify debugging parameters by
-            typing: 
-<pre>
-run &lt;your_params&gt;
-</pre>
-         </li>
-      </ol>
-      <p>
-         <a href="#top">Back to top</a>
-      </p>
-      <h3>
-         Attaching the Debugger to the Live Process
-      </h3>
-      <p>
-         To attach to the running VM process, do the following:
-      </p>
-      <p>
-         <strong>On Windows<a href="#*">*</a></strong>
-      </p>
-      <ol>
-         <li>
-            Start Visual Studio<a href="#*">*</a> .
-         </li>
-         <li>
-            Go <strong>Debug</strong> &gt;
-            <strong>Processes</strong>.
-         </li>
-         <li>
-            Select the VM process and click
-            <strong>Attach</strong>.<br>
-             If you built the VM in the debug mode, the
-            <strong>Microsoft Debug Runtime</strong> window appears.
-            Click the <strong>Debug</strong> button to go to the
-            crash point.
-         </li>
-      </ol>
-      <p>
-         <strong>On Linux<a href="#*">*</a></strong>
-      </p>
-      <p>
-         Run:
-      </p>
-<pre>
-gdb &ndash;p &lt;PID of ij&gt;
-</pre>
-      <p>
-         If the VM crashed during execution, use the core dump to
-         analyze the crash:
-      </p>
-<pre>
-gdb ij core
-</pre>
-      <p>
-         <a href="#top">Back to top</a>
-      </p>
-      <h2>
-         <a name="Extended_Debug_VM">How to get more from your
-         debugging?</a>
-      </h2>
-      <p>
-         This section includes some tips on optimizing the debug
-         process and getting more debug information.
-      </p>
-      <h3>
-         Configuration of tracing
-      </h3>
-      <p>
-         Consult the <i>Getting Started</i> guide delivered with
-         DRLVM bundle for information on VM standard and non-standard
-         configuration options. Tracing-related options might be
-         useful for debugging purposes.
-      </p>
-      <h3>
-         Native stack examination
-      </h3>
-      <p>
-         The debugger might draw the stack incorrectly when the JIT
-         or native stubs are involved. To avoid this, set esp as the
-         memory location and 4-byte integer values as the output
-         format. As a result, you can examine the stack word by word
-         and look into the code for each number 0x00&hellip; by using
-         the Disassembly window.
-      </p>
-      <blockquote>
-         <p style="font-weight: bold">
-            When the VM has crashed
-         </p>
-         <p>
-            A very specific case on Windows<a href="#*">*</a>: the VM
-            has crashed and you only see the stack frame in the call
-            stack <code>0x00000000</code>. This means that the
-            program has jumped or called to a null pointer.
-         </p>
-         <p>
-            You might still get the stack trace. For that, do the
-            following:
-         </p>
-         <ol>
-            <li>
-               Open the <strong>Disassembly</strong> window.
-            </li>
-            <li>
-               Find any ret instruction with no parameters in the
-               memory space.<br>
-                Open any source file, open the context menu, and
-               select <strong>Go</strong> to
-               <strong>Disassembly</strong> to find any
-               <code>ret</code> instruction.
-            </li>
-            <li>
-               When found, select the ret instruction and click
-               <strong>Set Next Statement</strong> in the context
-               menu.
-            </li>
-            <li>
-               Type <code>F11</code> to go a single instruction.<br>
-                You may see several instructions near the current
-               point of execution. If you see a call instruction, you
-               have found an appropriate call site and you can see
-               the call stack in the <strong>Call Stack</strong>
-               window. If you have found a wrong call site, repeat
-               the instruction from step 2.
-            </li>
-         </ol>
-      </blockquote>
-      <p>
-         <a href="#top">Back to top</a>
-      </p>
-      <h3>
-         Java<a href="#*">*</a> stack examination
-      </h3>
-      <p>
-         <strong>On Windows<a href="#*">*</a></strong>
-      </p>
-      <p>
-         Running the VM in the interpreter mode, you can get Java<a
-         href="#*">*</a> methods stack trace almost at any point of
-         execution. For that, break the execution of the VM and
-         select the <strong>Interpreter</strong> frame in the Visual
-         Studio<a href="#*">*</a> <strong>Call Stack</strong> window.
-         Then, in the watch window, add the watch
-         <code>stack_dump()</code>. The stack dump appears in VM
-         output window. Running the VM in the JIT mode, use the
-         <code>st_print()</code> function for the same purpose.
-      </p>
-      <p>
-         <strong>On Linux<a href="#*">*</a></strong>
-      </p>
-      <p>
-         Use the <code>gdb</code> command print and specify the
-         <code>stack_dump</code> or <code>st_print</code> in the
-         interpreter or the JIT compiler mode respectively.
-      </p>
-      <h3>
-         Setting smart breakpoints
-      </h3>
-      <p>
-         <strong>On Windows<a href="#*">*</a> / IA-32</strong>
-      </p>
-      <p>
-         Place breakpoints in source code by inserting calls to the
-         _CrtDbgBreak() function. Placing the call inside a condition
-         calls the function only for the specified case you need to
-         debug. Analogously, you can use the Windows<a href=
-         "#*">*</a> API function DebugBreak() or print INT 3.
-      </p>
-      <p>
-             <strong>Note</strong><br>
-              This requires recompiling the VM.
-      </p>
-      <p>
-         <strong>On Linux<a href="#*">*</a></strong>
-      </p>
-      <p>
-         Run the following:
-      </p>
-<pre>
-__asm {int 3}
-</pre>
-      <p>
-         <a href="#top">Back to top</a>
-      </p>
-      <h3>
-         Handling Java<a href="#*">*</a> threads as native threads
-      </h3>
-      <p>
-         DRL VM has 1:1 mapping between native threads visible in the
-         debugger and Java<a href="#*">*</a> threads.<br>
-          To work with Java<a href="#*">*</a> threads individually,
-         freeze the threads you do not need with the help of the
-         debugger, and continue execution of other threads.
-      </p>
-      <h3>
-         Debugging deadlocks with the CriticalSection synchronization
-         primitive
-      </h3>
-      <p>
-         The <code>CriticalSection</code> primitive is a common cause
-         of deadlocks. If the code has stopped at a critical section,
-         you can try to find the thread that owns this primitive.
-      </p>
-      <p>
-         <strong>On Windows<a href="#*">*</a></strong>
-      </p>
-      <p>
-         The file WinNT.H located in &lt;PlatformSDK&gt;\Include
-         contains the definition for the structure
-         _RTL_CRITICAL_SECTION, which contains the description of the
-         CriticalSection primitive. You can get the owning thread for
-         the CriticalSection primitive in a number of ways, as
-         indicated below.
-      </p>
-      <blockquote>
-         <p>
-            <strong>Lookup in Memory</strong>
-         </p>
-         <p>
-            On Windows<a href="#*">*</a>
-         </p>
-         <p>
-            While debugging the code in Visual Studio, do the
-            following:
-         </p>
-         <ol>
-            <li>
-               Go <strong>Debug</strong> &gt;
-               <strong>Windows</strong> &gt; <strong>Memory
-               1</strong>.
-            </li>
-            <li>
-               In the address line, enter the address of the critical
-               section.
-            </li>
-            <li>
-               Open the context menu and select 4-byte Integers. This
-               sets the fourth DWORD from the beginning of the
-               critical section as the owning thread ID in
-               hexadecimal representation.
-            </li>
-         </ol>
-         <p>
-                <strong>Note</strong><br>
-                 Visual Studio<a href="#*">*</a> displays thread IDs
-            in decimal representation.
-         </p>
-      </blockquote>
-      <blockquote>
-         <strong>In the watch window</strong> 
-         <p>
-            In the watch window of Visual Studio<a href="#*">*</a>,
-            insert the following:
-         </p>
-<pre>
-* ((int* )&lt;cs-ptr&gt;+3)
-</pre>
-         <p>
-            Where <code>&lt;cs-ptr&gt;</code> is the address of your
-            critical section
-         </p>
-      </blockquote>
-      <p>
-         <strong>On Linux<a href="#*">*</a></strong>
-      </p>
-      <p>
-         The file <code>/usr/include/bits/pthreadtypes.h</code>
-         contains the description of the <code>pthread_mutex_t</code>
-         type. To get the ID of the thread owning the
-         <code>CriticalSection</code> primitive, in gdb execute:
-      </p>
-<pre>
-x/4w &lt;address of your mutex primitive&gt;
-</pre>
-      <p>
-         The third word in the output contains the owning thread
-         descriptor you are looking for.
-      </p>
-      <h3>
-         Getting a class name for an object
-      </h3>
-      <p>
-         You can often need to find out the class name for a Java<a
-         href="#*">*</a> object used in VM code. For example, you may
-         need to get the class name for an object of the type
-         <code>ManagedObject *</code> (which is a direct pointer to
-         the heap). For that, insert the following expression into
-         the watch window in Visual Studio on Windows<a href=
-         "#*">*</a> or print the command of <code>gdb</code> on
-         Linux<a href="#*">*</a> :
-      </p>
-      <code>((VTable*)(*((int
-      *)obj)))-&gt;clss-&gt;name-&gt;bytes</code> 
-      <p>
-         Variables of the types jobject and
-         <code>Object_Handle</code> are references to
-         <code>ManagedObject *</code> types. These structures contain
-         a single element, a pointer to <code>ManagedObject *</code>
-         type object. To use the expression above, de-reference the
-         variable, for example, substituting <code>obj</code> in the
-         expression above with a cast to <code>(ManagedObject
-         *)(*(int *)obj)</code>.
-      </p>
-      <p>
-         <a href="#top">Back to top</a>
-      </p>
-      <h1>
-         <a name="Debugging_JIT"></a>Debugging the Jitrino.JET
-         Baseline Compiler
-      </h1>
-      <p>
-         To use debugging and tracing in Jitrino.JET, use the debug
-         build or the release build with the <code>JET_PROTO</code>
-         macro defined. See the file <code>jdefs.h</code> for a
-         definition of the available flags.
-      </p>
-      <h2>
-         <a name="Enable_Tracing"></a>How to enable tracing in
-         Jitrino.JET?
-      </h2>
-      <p>
-         Currently, Jitrino.JET provides no interface or command line
-         to control tracing options. To enable tracing, set the
-         <code>compile_flags</code> variable at the entry point to
-         the method <code>Compiler::compile()</code>. At that point,
-         the global variable <code>Compiler::g_methodsSeen</code>
-         contains the ID of the method being compiled, and the
-         instance variable <code>m_fname</code> contains its fully
-         qualified name with no signature. Obtain these options
-         through a call to
-         <code>Compiler::m_infoBlock.get_flags()</code>.
-      </p>
-      <h2>
-         <a name="Config_Trace_Logging"></a>How to configure trace
-         logging?
-      </h2>
-      <p>
-         Tracing flags control compilation results output and trace
-         run-time execution, as described below. Tracing results are
-         created in each run in the directory where the
-         <code>ij</code> executable starts: compilation results are
-         in <code>jet.log</code>, and run-time output is in
-         <code>jet.rt.log</code>.
-      </p>
-      <h3>
-         Group 1: Compilation Results Tracing
-      </h3>
-      <p>
-         The following flags control tracing compilation of a method:
-      </p>
-      <ul>
-         <li>
-            <strong><code>DBG_TRACE_SUMM</code></strong> prints a
-            short summary about the compiled method: the compilation
-            status (success or failure), the name, signature,
-            bytecode size, the start and end addresses of the
-            generated code, and the compilation ID (the sequential
-            number of the method compiled by Jitrino.JET).
-         </li>
-         <li>
-            <code><strong>DBG_DUMP_BBS</strong></code> dumps the
-            bytecode and marks up basic blocks boundaries.
-         </li>
-         <li>
-            <code><strong>DBG_TRACE_CG</strong></code> prints
-            information about each compiled bytecode instruction: the
-            state of the Java<a href="#*">*</a> operand stack before
-            the instruction, the known state of local variables at
-            the given point, and the native code generated for the
-            instruction. The order instructions appear in the log
-            file is the depth-first order, the same as when
-            processing instructions during compilation. See the file
-            trace.cpp, function <code>toStr2()</code> for the legend
-            of the operand stack items print-out.
-         </li>
-         <li>
-            <strong><code>DBG_TRACE_LAYOUT</code></strong> prints the
-            results of the code layout, mostly, the address ranges
-            for the basic blocks.
-         </li>
-         <li>
-            <strong><code>DBG_DUMP_CODE</code></strong> dumps
-            generated code for the given method, the method&rsquo;s
-            actual addresses, intermixed with appropriate bytecode
-            instructions. 
-            <p>
-                   <strong>Note</strong><br>
-                    For <code>DBG_DUMP_CODE</code> and
-               <code>DBG_TRACE_CG</code>, Jitrino.JET can print
-               disassembled code in addition to raw hexadecimal
-               dumps. For that, the compiler requires an external
-               disassembler. Currently, Jitrino.JET is configured to
-               use the external library
-               <code>lwdis.dll/liblwdis.so</code> that must be
-               located in the same directory as
-               <code>jitrino.dll/libjitrino.so</code>. The name lwdis
-               stands for light weight disassembler. The library must
-               export the function <code>disasm()</code>. Refer to
-               the file trace.cpp, the <code>DISFUNC</code>
-               definition for details on calling convention and
-               signature.
-            </p>
-         </li>
-         <li>
-            <strong><code>DBG_CHECK_STACK</code></strong> prints
-            nothing but instruments code to check stack integrity.
-            The methods compiled by Jitrino.JET use EBP-based frames.
-            These frames can mask errors, for example, wrong
-            convention usage with a VM helper call. Using this option
-            performs run-time checks and INT3 raised in case the
-            stack integrity broken.
-         </li>
-         <li>
-            <strong><code>DBG_BRK</code></strong> inserts INT3 at the
-            method entry point, so it can be stopped in the debugger.
-            
-            <p>
-                  <strong> Note</strong><br>
-                    An instance variable of class
-               <code>Compiler</code>, <code>dbg_break_pc</code> can
-               be used to insert <code>INT3</code> at the specified
-               program counter of a method.
-            </p>
-         </li>
-      </ul>
-      <p>
-         <a href="#top">Back to top</a>
-      </p>
-      <h3>
-         Group 2: Run-time Execution tracing
-      </h3>
-      <p>
-         The following flags trace run-time life of the method:
-      </p>
-      <ul class="noindent">
-         <li>
-            <strong><code>DBG_TRACE_EE</code></strong> prints
-            entering: <code>&lt;method-name&gt;</code> and exiting:
-            <code>&lt;method-name&gt;</code> at the method entrance
-            and exit points.<br>
-            <br>
-         </li>
-         <li>
-            <strong><code>DBG_TRACE_BC</code></strong> traces
-            execution of every bytecode instruction by printing a
-            string of the following format before executing the
-            instruction: <code>&lt;method-name&gt; @
-            PC=&lt;pc&gt;</code><br>
-            <br>
-         </li>
-      </ul>
-      <p>
-         <strong>    Notes</strong>
-      </p>
-      <p>
-             The output string for <code>DBG_TRACE_EE</code> and
-         <code>DBG_TRACE_BC</code> uses a specific format: before the
-         string, an estimated call depth is printed and the string
-         gets indentation based on the call depth. After the string,
-         the string ID is printed. The estimated call depth may help
-         to identify where a method was called from. The string ID
-         can be helpful for setting a conditional breakpoint in the
-         debugger for a complex scenario. For that, set a condition
-         for the static variable cnt in the function
-         <code>rt_dbg</code>, file <code>trace.cpp</code>.
-      </p>
-      <p class="Notetext">
-             Turning on the option <code>DBG_TRACE_BC</code> may slow
-         down execution extremely and may result to a gigantic file
-         <code>jet.rt.log</code>.
-      </p>
-      <ul class="noindent">
-         <li>
-            <strong><code>DBG_TRACE_RT</code></strong> traces
-            run-time support calls, for example, getting address of
-            &lsquo;this&rsquo;, support for root set enumeration and
-            stack unwinding.<br>
-            <br>
-         </li>
-      </ul>
-      <p>
-         <strong>    Note</strong><br>
-              The output goes to jet.log, with the address (both
-         native and PC) where the event happens, and some other info.
-      </p>
-      <p>
-         <a href="#top">Back to top</a>
-      </p>
-      <h2>
-         <a name="Extend_Trace_JIT">How to get more from your
-         tracing?</a>
-      </h2>
-      <p>
-         To identify one or more problematic methods with another
-         stable JIT compiler, use the execution manager. With this
-         technique, some methods are compiled by the stable JIT, and
-         the rest goes to the JIT being debugged. With a simple
-         binary search, you can find the problematic method rather
-         quickly.
-      </p>
-      <p>
-         <strong>    Note</strong><br>
-              Try turning off parallel compilation when using this
-         technique (refer to VM&rsquo;s
-         <code>-Xno_parallel_jit</code> option).
-      </p>
-      <p>
-         <b>To get details in case of a crash</b> with no adequate
-         stack trace or IP location available, turn on the option
-         DBG_TRACE_EE to see, in which method the crash happens. As
-         the second step, turn on DBG_TRACE_BC for this particular
-         method to find the exact bytecode instruction. Often, this
-         cuts the code to analyze down to 5-10 native instructions.
-      </p>
-      <p>
-         <b>To set a breakpoint and stop execution at a specific
-         point</b>, use trace.cpp:rt_dbg to break execution at the
-         specified bytecode instruction or at the entry point of the
-         specified method.
-      </p>
-      <p>
-         <a href="#top">Back to top</a>
-      </p>
-      <h3>
-         Tracing Example
-      </h3>
-      <p>
-         This is an example of code that turns on various tracing
-         scenarios. The code must be placed in the method
-         <code>Compiler::compile(</code>).
-      </p>
-      <p>
-         <span style="font-family:Courier 
-         New;font-size:10.0pt;color:blue;">#if</span> <span style= 
-         "font-family:Courier New;font-size:10.0pt;"><span style= 
-         "color:blue;">defined</span>(<span style=
-         "color:black;">_DEBUG</span>) || <span style=
-         "color:blue;">defined</span>(<span style=
-         "color:black;">JET_PROTO</span>)</span>
-      </p>
-      <p>
-         <span style="font-family:Courier
-         New;font-size:10.0pt;"><span style="color:green;">    //
-         Turns on a short summary of all methods</span></span>
-      </p>
-      <p>
-         <span style="font-family:Courier
-         New;font-size:10.0pt;"><span style=
-         "color:black;">    compile_flags</span> |= <span style= 
-         "color:black;">DBG_TRACE_SUMM</span>;</span>
-      </p>
-      <p>
-         <span style="font-family:Courier
-         New;font-size:10.0pt;"><span style="color:green;">    // A
-         handy constant</span></span>
-      </p>
-      <p>
-         <span style="font-family:Courier
-         New;font-size:10.0pt;"><span style=
-         "color:blue;">    static</span> <span style=
-         "color:blue;">const</span> <span style=
-         "color:blue;">unsigned</span> <span style=
-         "color:black;">TRACE_CG</span> = <span style=
-         "color:black;">DBG_DUMP_BBS</span> | <span style= 
-         "color:black;">DBG_TRACE_CG</span> |</span>
-      </p>
-      <p>
-         <span style="font-family:Courier
-         New;font-size:10.0pt;"><span style=
-         "color:black;">                                     DBG_TRACE_LAYOUT</span>
-         | <span style="color:black;">DBG_TRACE_SUMM</span> |</span>
-      </p>
-      <p>
-         <span style="font-family:Courier
-         New;font-size:10.0pt;"><span style=
-         "color:black;">                                     DBG_DUMP_CODE</span>;</span>
-      </p>
-      <p>
-         <span style="font-family:Courier
-         New;font-size:10.0pt;"><span style="color:green;">    // For
-         methods in the range (1000;15000), print out the complete
-         code generator dumps</span></span>
-      </p>
-      <p>
-         <span style="font-family:Courier
-         New;font-size:10.0pt;"><span style=
-         "color:blue;">    if</span> (<span style=
-         "color:black;">g_methodsSeen</span>&gt;1000 &amp;&amp; <span
-         style="color:black;">g_methodsSeen</span>&lt;15000) {</span>
-      </p>
-      <p>
-         <span style="font-family:Courier
-         New;font-size:10.0pt;"><span style=
-         "color:black;">    compile_flags</span> |= <span style= 
-         "color:black;">TRACE_CG</span>;</span>
-      </p>
-      <p>
-         <span style="font-family:Courier
-         New;font-size:10.0pt;">    }</span>
-      </p>
-      <p>
-         <span style="font-family:Courier
-         New;font-size:10.0pt;"><span style="color:green;">    // For
-         methods getSomeValue() and for all methods in class
-         MyClass,</span></span>
-      </p>
-      <p>
-         <span style="font-family:Courier
-         New;font-size:10.0pt;"><span style="color:green;">    //
-         trace enter and exit</span></span>
-      </p>
-      <p>
-         <span style="font-family:Courier
-         New;font-size:10.0pt;"><span style=
-         "color:blue;">    if</span> (<span style=
-         "color:black;">NULL</span> != <span style=
-         "color:black;">strstr</span>(<span style=
-         "color:black;">m_fname</span>, "::getSomeValue") ||</span>
-      </p>
-      <p>
-         <span style="font-family:Courier
-         New;font-size:10.0pt;"><span style=
-         "color:black;">        NULL</span> != <span style= 
-         "color:black;">strstr</span>(<span style=
-         "color:black;">m_fname</span>, "MyClass::") ) {</span>
-      </p>
-      <p>
-         <span style="font-family:Courier
-         New;font-size:10.0pt;"><span style=
-         "color:black;">        compile_flags</span> |= <span style= 
-         "color:black;">    DBG_TRACE_EE</span>;</span>
-      </p>
-      <p>
-         <span style="font-family:Courier
-         New;font-size:10.0pt;">    }</span>
-      </p>
-      <p>
-         <span style="font-family:Courier
-         New;font-size:10.0pt;"><span style="color:green;">    // For
-         the method crashes_some_times() in class MyClass trace
-         every</span></span>
-      </p>
-      <p>
-         <span style="font-family:Courier
-         New;font-size:10.0pt;"><span style="color:green;">    //
-         bytecode execution: the last bytecode in the log is the most
-         probable</span></span>
-      </p>
-      <p>
-         <span style="font-family:Courier
-         New;font-size:10.0pt;"><span style="color:green;">    //
-         cause of the failure</span></span>
-      </p>
-      <p>
-         <span style="font-family:Courier
-         New;font-size:10.0pt;"><span style=
-         "color:blue;">    if</span> (!<span style=
-         "color:black;">strcmp</span>(<span style=
-         "color:black;">m_fname</span>,
-         "MyClass::crashes_some_times")) {</span>
-      </p>
-      <p>
-         <span style="font-family:Courier
-         New;font-size:10.0pt;"><span style=
-         "color:black;">        compile_flags</span> |= <span style= 
-         "color:black;">DBG_TRACE_EE</span>|<span style=
-         "color:black;">DBG_TRACE_BC</span>;</span>
-      </p>
-      <p>
-         <span style="font-family:Courier
-         New;font-size:10.0pt;">    }</span>
-      </p>
-      <p>
-         <span style="font-family:Courier
-         New;font-size:10.0pt;"><span style="color:green;">    //
-         Break into debugger (INT3) at the entry of the
-         stop_at_entry() method</span></span>
-      </p>
-      <p>
-         <span style="font-family:Courier
-         New;font-size:10.0pt;"><span style=
-         "color:blue;">    if</span> (!<span style=
-         "color:black;">strcmp</span>(<span style=
-         "color:black;">m_fname</span>, "MyClass::stop_at_entry"))
-         {</span>
-      </p>
-      <p>
-         <span style="font-family:Courier
-         New;font-size:10.0pt;"><span style=
-         "color:black;">        compile_flags</span> |= <span style= 
-         "color:black;">DBG_BRK</span>;</span>
-      </p>
-      <p>
-         <span style="font-family:Courier
-         New;font-size:10.0pt;">    }</span>
-      </p>
-      <p>
-         <span style="font-family:Courier
-         New;font-size:10.0pt;"><span style="color:green;">    //
-         Break into debugger (INT3) inside the method</span></span>
-      </p>
-      <p>
-         <span style="font-family:Courier
-         New;font-size:10.0pt;"><span style=
-         "color:blue;">    if</span> (!<span style=
-         "color:black;">strcmp</span>(<span style=
-         "color:black;">m_fname</span>,
-         "MyClass::stop_somewhere_in_the_middle")) {</span>
-      </p>
-      <p>
-         <span style="font-family:Courier
-         New;font-size:10.0pt;"><span style=
-         "color:black;">        dbg_break_pc</span> = 50;</span>
-      </p>
-      <p>
-         <span style="font-family:Courier
-         New;font-size:10.0pt;">    }</span>
-      </p>
-      <p>
-         <span style="font-family:Courier
-         New;font-size:10.0pt;"><span style="color:green;">    //
-         Trace run-time support calls: unwind, getting the address of
-         'this', root</span></span>
-      </p>
-      <p>
-         <span style="font-family:Courier
-         New;font-size:10.0pt;"><span style="color:green;">    // set
-         enumeration</span></span>
-      </p>
-      <p>
-         <span style="font-family:Courier
-         New;font-size:10.0pt;"><span style=
-         "color:blue;">    if</span> (!<span style=
-         "color:black;">strcmp</span>(<span style=
-         "color:black;">m_fname</span>,
-         "MyClass::something_wrong_with_unwind_here")) {</span>
-      </p>
-      <p>
-         <span style="font-family:Courier
-         New;font-size:10.0pt;"><span style=
-         "color:black;">        compile_flags</span> |= <span style= 
-         "color:black;">DBG_TRACE_RT</span>;</span>
-      </p>
-      <p>
-         <span style="font-family:Courier
-         New;font-size:10.0pt;">    }</span>
-      </p>
-      <p>
-         <span style="font-family:Courier
-         New;font-size:10.0pt;"><span style="color:green;">    //
-         By-pass run-time tracing for java/* classes</span></span>
-      </p>
-      <p>
-         <span style="font-family:Courier
-         New;font-size:10.0pt;"><span style=
-         "color:blue;">    if</span> (<span style=
-         "color:black;">m_fname</span> == <span style=
-         "color:black;">strstr</span>(<span style=
-         "color:black;">m_fname</span>, "java/")) {</span>
-      </p>
-      <p>
-         <span style="font-family:Courier
-         New;font-size:10.0pt;"><span style=
-         "color:black;">        compile_flags</span> &amp;= ~(<span
-         style="color:black;">DBG_TRACE_EE</span>|<span style= 
-         "color:black;">DBG_TRACE_BC</span>);</span>
-      </p>
-      <p>
-         <span style="font-family:Courier
-         New;font-size:10.0pt;">    }</span>
-      </p>
-      <p>
-         <span style="font-family:Courier 
-         New;font-size:10.0pt;color:blue;">#endif</span>
-      </p>
-      <p>
-          
-      </p>
-      <p>
-         <a href="#top">Back to top</a>
-      </p>
-      <p>
-         <a name="*"></a>* Other brands and names are the property of
-         their respective owners.
-      </p>
-   </body>
-</html>
-
+<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
+<html>
+   <head>
+      <meta http-equiv="Content-Type" content=
+      "text/html; charset=windows-1251">
+      <title>
+         Debugging DRL Virtual Machine and JIT Compiler
+      </title>
+   </head>
+   <body>
+      <h1>
+         <a name="top"></a>Debugging the DRL Virtual Machine and the
+         JIT Compiler
+      </h1>
+      <p>
+         This document gives practical instructions on how to debug
+         the DRL virtual machine and its baseline just-in-time
+         compiler Jitrino.JET. For a definition of components and
+         details on their internal structure, consult the <i>DRL
+         Virtual Machine Developer&rsquo;s Guide</i> supplied with
+         the DRLVM image.
+      </p>
+      <p>
+         The document includes two groups of debugging tips, one for
+         VM tips, and the other for JIT compiler tips, as shown
+         below.
+      </p>
+      <p>
+         <a href="#Disclaimer">Disclaimer and Legal Information</a>
+      </p>
+      <p>
+         <a href="#Debugging_VM">Debugging the Virtual Machine</a>
+      </p>
+      <blockquote>
+         <p>
+            <a href="#How_to_debug_VM">How to debug the VM?</a>
+         </p>
+         <p>
+            <a href="#Extended_Debug_VM">How to get more of your
+            debugging?</a>
+         </p>
+      </blockquote>
+      <p>
+         <a href="#Debugging_JIT">Debugging the Jitrino.JET Baseline
+         Compiler</a>
+      </p>
+      <blockquote>
+         <p>
+            <a href="#Enable_Tracing">How to enable tracing in
+            Jitrino.JET?</a>
+         </p>
+         <p>
+            <a href="#Config_Trace_Logging">How to configure trace
+            logging?</a>
+         </p>
+         <p>
+            <a href="#Extend_Trace_JIT">How to get more of your
+            tracing?</a>
+         </p>
+      </blockquote>
+      <h1>
+         <a name="Disclaimer">Disclaimer and Legal Information</a>
+      </h1>
+      <p>
+         Copyright 2006 The Apache Software Foundation or its
+         licensors, as applicable.
+      </p>
+      <p>
+         Licensed under the Apache License, Version 2.0 (the
+         License); you may not use this file except in compliance
+         with the License. You may obtain a copy of the License at <a
+         href="http://www.apache.org/licenses/LICENSE-2.0" target= 
+         "_blank">http://www.apache.org/licenses/LICENSE-2.0</a>.
+      </p>
+      <p>
+         Unless required by applicable law or agreed to in writing,
+         software distributed under the License is distributed on an
+         AS IS BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
+         either express or implied. See the License for the specific
+         language governing permissions and limitations under the
+         License.
+      </p>
+      <p>
+         <a href="#top">Back to top</a>
+      </p>
+      <h1>
+         <a name="Debugging_VM">Debugging the Virtual Machine</a>
+      </h1>
+      <p>
+         This section gives an insight into debugging the DRL virtual
+         machine version 1.0 and provides tips on resolving
+         non-standard debugging issues.
+      </p>
+      <h2>
+         <a name="How_to_debug_VM">How to debug the VM?</a>
+      </h2>
+      <p>
+         This section gives instructions on different scenarios of
+         debugging the VM source code.
+      </p>
+      <h3>
+         Basic Debugging Steps
+      </h3>
+      <p>
+         For ordinary tests, start the ij executable with the
+         debugger enabled, as follows:
+      </p>
+      <p>
+         <strong>On Windows<a href="#*">*</a></strong>
+      </p>
+      <ol>
+         <li>
+            Start Microsoft Visual Studio<a href="#*">*</a> and open
+            the solution file <code>vm\build\vm.sln</code>.
+         </li>
+         <li>
+            Open the source code that you need to debug, set
+            breakpoints and perform all other preliminary steps.
+         </li>
+         <li>
+            Select the vmcore project and open its properties to
+            specify the location of the <code>ij</code> executable.
+            Select the <strong>Debugging</strong> tab and specify the
+            command and command arguments.
+         </li>
+         <li>
+            Copy the ZLib tool library <code>zlib1.dll</code> to the
+            location of the VM executable.
+         </li>
+         <li>
+            Start debugging via the menu <strong>Debug</strong> &gt;
+            <strong>Start</strong>, click <strong>NO</strong> in the
+            popup dialog offering to build the project.
+         </li>
+      </ol>
+      <p>
+         <strong>On Linux<a href="#*">*</a></strong>
+      </p>
+      <ol>
+         <li>
+            Set up the <code>LD_LIBRARY_PATH</code> to point to the
+            <code>deploy/jre/bin</code> directory. Change the working
+            directory to the location of the VM executable and run: 
+<pre>
+gdb ij
+</pre>
+         </li>
+         <li>
+            Set breakpoints and perform all other preliminary steps.
+         </li>
+         <li>
+            On the command line, specify debugging parameters by
+            typing: 
+<pre>
+run &lt;your_params&gt;
+</pre>
+         </li>
+      </ol>
+      <p>
+         <a href="#top">Back to top</a>
+      </p>
+      <h3>
+         Attaching the Debugger to the Live Process
+      </h3>
+      <p>
+         To attach to the running VM process, do the following:
+      </p>
+      <p>
+         <strong>On Windows<a href="#*">*</a></strong>
+      </p>
+      <ol>
+         <li>
+            Start Visual Studio<a href="#*">*</a> .
+         </li>
+         <li>
+            Go <strong>Debug</strong> &gt;
+            <strong>Processes</strong>.
+         </li>
+         <li>
+            Select the VM process and click
+            <strong>Attach</strong>.<br>
+             If you built the VM in the debug mode, the
+            <strong>Microsoft Debug Runtime</strong> window appears.
+            Click the <strong>Debug</strong> button to go to the
+            crash point.
+         </li>
+      </ol>
+      <p>
+         <strong>On Linux<a href="#*">*</a></strong>
+      </p>
+      <p>
+         Run:
+      </p>
+<pre>
+gdb &ndash;p &lt;PID of ij&gt;
+</pre>
+      <p>
+         If the VM crashed during execution, use the core dump to
+         analyze the crash:
+      </p>
+<pre>
+gdb ij core
+</pre>
+      <p>
+         <a href="#top">Back to top</a>
+      </p>
+      <h2>
+         <a name="Extended_Debug_VM">How to get more from your
+         debugging?</a>
+      </h2>
+      <p>
+         This section includes some tips on optimizing the debug
+         process and getting more debug information.
+      </p>
+      <h3>
+         Configuration of tracing
+      </h3>
+      <p>
+         Consult the <i>Getting Started</i> guide delivered with
+         DRLVM bundle for information on VM standard and non-standard
+         configuration options. Tracing-related options might be
+         useful for debugging purposes.
+      </p>
+      <h3>
+         Native stack examination
+      </h3>
+      <p>
+         The debugger might draw the stack incorrectly when the JIT
+         or native stubs are involved. To avoid this, set esp as the
+         memory location and 4-byte integer values as the output
+         format. As a result, you can examine the stack word by word
+         and look into the code for each number 0x00&hellip; by using
+         the Disassembly window.
+      </p>
+      <blockquote>
+         <p style="font-weight: bold">
+            When the VM has crashed
+         </p>
+         <p>
+            A very specific case on Windows<a href="#*">*</a>: the VM
+            has crashed and you only see the stack frame in the call
+            stack <code>0x00000000</code>. This means that the
+            program has jumped or called to a null pointer.
+         </p>
+         <p>
+            You might still get the stack trace. For that, do the
+            following:
+         </p>
+         <ol>
+            <li>
+               Open the <strong>Disassembly</strong> window.
+            </li>
+            <li>
+               Find any ret instruction with no parameters in the
+               memory space.<br>
+                Open any source file, open the context menu, and
+               select <strong>Go</strong> to
+               <strong>Disassembly</strong> to find any
+               <code>ret</code> instruction.
+            </li>
+            <li>
+               When found, select the ret instruction and click
+               <strong>Set Next Statement</strong> in the context
+               menu.
+            </li>
+            <li>
+               Type <code>F11</code> to go a single instruction.<br>
+                You may see several instructions near the current
+               point of execution. If you see a call instruction, you
+               have found an appropriate call site and you can see
+               the call stack in the <strong>Call Stack</strong>
+               window. If you have found a wrong call site, repeat
+               the instruction from step 2.
+            </li>
+         </ol>
+      </blockquote>
+      <p>
+         <a href="#top">Back to top</a>
+      </p>
+      <h3>
+         Java<a href="#*">*</a> stack examination
+      </h3>
+      <p>
+         <strong>On Windows<a href="#*">*</a></strong>
+      </p>
+      <p>
+         Running the VM in the interpreter mode, you can get Java<a
+         href="#*">*</a> methods stack trace almost at any point of
+         execution. For that, break the execution of the VM and
+         select the <strong>Interpreter</strong> frame in the Visual
+         Studio<a href="#*">*</a> <strong>Call Stack</strong> window.
+         Then, in the watch window, add the watch
+         <code>stack_dump()</code>. The stack dump appears in VM
+         output window. Running the VM in the JIT mode, use the
+         <code>st_print()</code> function for the same purpose.
+      </p>
+      <p>
+         <strong>On Linux<a href="#*">*</a></strong>
+      </p>
+      <p>
+         Use the <code>gdb</code> command print and specify the
+         <code>stack_dump</code> or <code>st_print</code> in the
+         interpreter or the JIT compiler mode respectively.
+      </p>
+      <h3>
+         Setting smart breakpoints
+      </h3>
+      <p>
+         <strong>On Windows<a href="#*">*</a> / IA-32</strong>
+      </p>
+      <p>
+         Place breakpoints in source code by inserting calls to the
+         _CrtDbgBreak() function. Placing the call inside a condition
+         calls the function only for the specified case you need to
+         debug. Analogously, you can use the Windows<a href=
+         "#*">*</a> API function DebugBreak() or print INT 3.
+      </p>
+      <p>
+             <strong>Note</strong><br>
+              This requires recompiling the VM.
+      </p>
+      <p>
+         <strong>On Linux<a href="#*">*</a></strong>
+      </p>
+      <p>
+         Run the following:
+      </p>
+<pre>
+__asm {int 3}
+</pre>
+      <p>
+         <a href="#top">Back to top</a>
+      </p>
+      <h3>
+         Handling Java<a href="#*">*</a> threads as native threads
+      </h3>
+      <p>
+         DRL VM has 1:1 mapping between native threads visible in the
+         debugger and Java<a href="#*">*</a> threads.<br>
+          To work with Java<a href="#*">*</a> threads individually,
+         freeze the threads you do not need with the help of the
+         debugger, and continue execution of other threads.
+      </p>
+      <h3>
+         Debugging deadlocks with the CriticalSection synchronization
+         primitive
+      </h3>
+      <p>
+         The <code>CriticalSection</code> primitive is a common cause
+         of deadlocks. If the code has stopped at a critical section,
+         you can try to find the thread that owns this primitive.
+      </p>
+      <p>
+         <strong>On Windows<a href="#*">*</a></strong>
+      </p>
+      <p>
+         The file WinNT.H located in &lt;PlatformSDK&gt;\Include
+         contains the definition for the structure
+         _RTL_CRITICAL_SECTION, which contains the description of the
+         CriticalSection primitive. You can get the owning thread for
+         the CriticalSection primitive in a number of ways, as
+         indicated below.
+      </p>
+      <blockquote>
+         <p>
+            <strong>Lookup in Memory</strong>
+         </p>
+         <p>
+            On Windows<a href="#*">*</a>
+         </p>
+         <p>
+            While debugging the code in Visual Studio, do the
+            following:
+         </p>
+         <ol>
+            <li>
+               Go <strong>Debug</strong> &gt;
+               <strong>Windows</strong> &gt; <strong>Memory
+               1</strong>.
+            </li>
+            <li>
+               In the address line, enter the address of the critical
+               section.
+            </li>
+            <li>
+               Open the context menu and select 4-byte Integers. This
+               sets the fourth DWORD from the beginning of the
+               critical section as the owning thread ID in
+               hexadecimal representation.
+            </li>
+         </ol>
+         <p>
+                <strong>Note</strong><br>
+                 Visual Studio<a href="#*">*</a> displays thread IDs
+            in decimal representation.
+         </p>
+      </blockquote>
+      <blockquote>
+         <strong>In the watch window</strong> 
+         <p>
+            In the watch window of Visual Studio<a href="#*">*</a>,
+            insert the following:
+         </p>
+<pre>
+* ((int* )&lt;cs-ptr&gt;+3)
+</pre>
+         <p>
+            Where <code>&lt;cs-ptr&gt;</code> is the address of your
+            critical section
+         </p>
+      </blockquote>
+      <p>
+         <strong>On Linux<a href="#*">*</a></strong>
+      </p>
+      <p>
+         The file <code>/usr/include/bits/pthreadtypes.h</code>
+         contains the description of the <code>pthread_mutex_t</code>
+         type. To get the ID of the thread owning the
+         <code>CriticalSection</code> primitive, in gdb execute:
+      </p>
+<pre>
+x/4w &lt;address of your mutex primitive&gt;
+</pre>
+      <p>
+         The third word in the output contains the owning thread
+         descriptor you are looking for.
+      </p>
+      <h3>
+         Getting a class name for an object
+      </h3>
+      <p>
+         You can often need to find out the class name for a Java<a
+         href="#*">*</a> object used in VM code. For example, you may
+         need to get the class name for an object of the type
+         <code>ManagedObject *</code> (which is a direct pointer to
+         the heap). For that, insert the following expression into
+         the watch window in Visual Studio on Windows<a href=
+         "#*">*</a> or print the command of <code>gdb</code> on
+         Linux<a href="#*">*</a> :
+      </p>
+      <code>((VTable*)(*((int
+      *)obj)))-&gt;clss-&gt;name-&gt;bytes</code> 
+      <p>
+         Variables of the types jobject and
+         <code>Object_Handle</code> are references to
+         <code>ManagedObject *</code> types. These structures contain
+         a single element, a pointer to <code>ManagedObject *</code>
+         type object. To use the expression above, de-reference the
+         variable, for example, substituting <code>obj</code> in the
+         expression above with a cast to <code>(ManagedObject
+         *)(*(int *)obj)</code>.
+      </p>
+      <p>
+         <a href="#top">Back to top</a>
+      </p>
+      <h1>
+         <a name="Debugging_JIT"></a>Debugging the Jitrino.JET
+         Baseline Compiler
+      </h1>
+      <p>
+         To use debugging and tracing in Jitrino.JET, use the debug
+         build or the release build with the <code>JET_PROTO</code>
+         macro defined. See the file <code>jdefs.h</code> for a
+         definition of the available flags.
+      </p>
+      <h2>
+         <a name="Enable_Tracing"></a>How to enable tracing in
+         Jitrino.JET?
+      </h2>
+      <p>
+         Currently, Jitrino.JET provides no interface or command line
+         to control tracing options. To enable tracing, set the
+         <code>compile_flags</code> variable at the entry point to
+         the method <code>Compiler::compile()</code>. At that point,
+         the global variable <code>Compiler::g_methodsSeen</code>
+         contains the ID of the method being compiled, and the
+         instance variable <code>m_fname</code> contains its fully
+         qualified name with no signature. Obtain these options
+         through a call to
+         <code>Compiler::m_infoBlock.get_flags()</code>.
+      </p>
+      <h2>
+         <a name="Config_Trace_Logging"></a>How to configure trace
+         logging?
+      </h2>
+      <p>
+         Tracing flags control compilation results output and trace
+         run-time execution, as described below. Tracing results are
+         created in each run in the directory where the
+         <code>ij</code> executable starts: compilation results are
+         in <code>jet.log</code>, and run-time output is in
+         <code>jet.rt.log</code>.
+      </p>
+      <h3>
+         Group 1: Compilation Results Tracing
+      </h3>
+      <p>
+         The following flags control tracing compilation of a method:
+      </p>
+      <ul>
+         <li>
+            <strong><code>DBG_TRACE_SUMM</code></strong> prints a
+            short summary about the compiled method: the compilation
+            status (success or failure), the name, signature,
+            bytecode size, the start and end addresses of the
+            generated code, and the compilation ID (the sequential
+            number of the method compiled by Jitrino.JET).
+         </li>
+         <li>
+            <code><strong>DBG_DUMP_BBS</strong></code> dumps the
+            bytecode and marks up basic blocks boundaries.
+         </li>
+         <li>
+            <code><strong>DBG_TRACE_CG</strong></code> prints
+            information about each compiled bytecode instruction: the
+            state of the Java<a href="#*">*</a> operand stack before
+            the instruction, the known state of local variables at
+            the given point, and the native code generated for the
+            instruction. The order instructions appear in the log
+            file is the depth-first order, the same as when
+            processing instructions during compilation. See the file
+            trace.cpp, function <code>toStr2()</code> for the legend
+            of the operand stack items print-out.
+         </li>
+         <li>
+            <strong><code>DBG_TRACE_LAYOUT</code></strong> prints the
+            results of the code layout, mostly, the address ranges
+            for the basic blocks.
+         </li>
+         <li>
+            <strong><code>DBG_DUMP_CODE</code></strong> dumps
+            generated code for the given method, the method&rsquo;s
+            actual addresses, intermixed with appropriate bytecode
+            instructions. 
+            <p>
+                   <strong>Note</strong><br>
+                    For <code>DBG_DUMP_CODE</code> and
+               <code>DBG_TRACE_CG</code>, Jitrino.JET can print
+               disassembled code in addition to raw hexadecimal
+               dumps. For that, the compiler requires an external
+               disassembler. Currently, Jitrino.JET is configured to
+               use the external library
+               <code>lwdis.dll/liblwdis.so</code> that must be
+               located in the same directory as
+               <code>jitrino.dll/libjitrino.so</code>. The name lwdis
+               stands for light weight disassembler. The library must
+               export the function <code>disasm()</code>. Refer to
+               the file trace.cpp, the <code>DISFUNC</code>
+               definition for details on calling convention and
+               signature.
+            </p>
+         </li>
+         <li>
+            <strong><code>DBG_CHECK_STACK</code></strong> prints
+            nothing but instruments code to check stack integrity.
+            The methods compiled by Jitrino.JET use EBP-based frames.
+            These frames can mask errors, for example, wrong
+            convention usage with a VM helper call. Using this option
+            performs run-time checks and INT3 raised in case the
+            stack integrity broken.
+         </li>
+         <li>
+            <strong><code>DBG_BRK</code></strong> inserts INT3 at the
+            method entry point, so it can be stopped in the debugger.
+            
+            <p>
+                  <strong> Note</strong><br>
+                    An instance variable of class
+               <code>Compiler</code>, <code>dbg_break_pc</code> can
+               be used to insert <code>INT3</code> at the specified
+               program counter of a method.
+            </p>
+         </li>
+      </ul>
+      <p>
+         <a href="#top">Back to top</a>
+      </p>
+      <h3>
+         Group 2: Run-time Execution tracing
+      </h3>
+      <p>
+         The following flags trace run-time life of the method:
+      </p>
+      <ul class="noindent">
+         <li>
+            <strong><code>DBG_TRACE_EE</code></strong> prints
+            entering: <code>&lt;method-name&gt;</code> and exiting:
+            <code>&lt;method-name&gt;</code> at the method entrance
+            and exit points.<br>
+            <br>
+         </li>
+         <li>
+            <strong><code>DBG_TRACE_BC</code></strong> traces
+            execution of every bytecode instruction by printing a
+            string of the following format before executing the
+            instruction: <code>&lt;method-name&gt; @
+            PC=&lt;pc&gt;</code><br>
+            <br>
+         </li>
+      </ul>
+      <p>
+         <strong>    Notes</strong>
+      </p>
+      <p>
+             The output string for <code>DBG_TRACE_EE</code> and
+         <code>DBG_TRACE_BC</code> uses a specific format: before the
+         string, an estimated call depth is printed and the string
+         gets indentation based on the call depth. After the string,
+         the string ID is printed. The estimated call depth may help
+         to identify where a method was called from. The string ID
+         can be helpful for setting a conditional breakpoint in the
+         debugger for a complex scenario. For that, set a condition
+         for the static variable cnt in the function
+         <code>rt_dbg</code>, file <code>trace.cpp</code>.
+      </p>
+      <p class="Notetext">
+             Turning on the option <code>DBG_TRACE_BC</code> may slow
+         down execution extremely and may result to a gigantic file
+         <code>jet.rt.log</code>.
+      </p>
+      <ul class="noindent">
+         <li>
+            <strong><code>DBG_TRACE_RT</code></strong> traces
+            run-time support calls, for example, getting address of
+            &lsquo;this&rsquo;, support for root set enumeration and
+            stack unwinding.<br>
+            <br>
+         </li>
+      </ul>
+      <p>
+         <strong>    Note</strong><br>
+              The output goes to jet.log, with the address (both
+         native and PC) where the event happens, and some other info.
+      </p>
+      <p>
+         <a href="#top">Back to top</a>
+      </p>
+      <h2>
+         <a name="Extend_Trace_JIT">How to get more from your
+         tracing?</a>
+      </h2>
+      <p>
+         To identify one or more problematic methods with another
+         stable JIT compiler, use the execution manager. With this
+         technique, some methods are compiled by the stable JIT, and
+         the rest goes to the JIT being debugged. With a simple
+         binary search, you can find the problematic method rather
+         quickly.
+      </p>
+      <p>
+         <strong>    Note</strong><br>
+              Try turning off parallel compilation when using this
+         technique (refer to VM&rsquo;s
+         <code>-Xno_parallel_jit</code> option).
+      </p>
+      <p>
+         <b>To get details in case of a crash</b> with no adequate
+         stack trace or IP location available, turn on the option
+         DBG_TRACE_EE to see, in which method the crash happens. As
+         the second step, turn on DBG_TRACE_BC for this particular
+         method to find the exact bytecode instruction. Often, this
+         cuts the code to analyze down to 5-10 native instructions.
+      </p>
+      <p>
+         <b>To set a breakpoint and stop execution at a specific
+         point</b>, use trace.cpp:rt_dbg to break execution at the
+         specified bytecode instruction or at the entry point of the
+         specified method.
+      </p>
+      <p>
+         <a href="#top">Back to top</a>
+      </p>
+      <h3>
+         Tracing Example
+      </h3>
+      <p>
+         This is an example of code that turns on various tracing
+         scenarios. The code must be placed in the method
+         <code>Compiler::compile(</code>).
+      </p>
+      <p>
+         <span style="font-family:Courier 
+         New;font-size:10.0pt;color:blue;">#if</span> <span style= 
+         "font-family:Courier New;font-size:10.0pt;"><span style= 
+         "color:blue;">defined</span>(<span style=
+         "color:black;">_DEBUG</span>) || <span style=
+         "color:blue;">defined</span>(<span style=
+         "color:black;">JET_PROTO</span>)</span>
+      </p>
+      <p>
+         <span style="font-family:Courier
+         New;font-size:10.0pt;"><span style="color:green;">    //
+         Turns on a short summary of all methods</span></span>
+      </p>
+      <p>
+         <span style="font-family:Courier
+         New;font-size:10.0pt;"><span style=
+         "color:black;">    compile_flags</span> |= <span style= 
+         "color:black;">DBG_TRACE_SUMM</span>;</span>
+      </p>
+      <p>
+         <span style="font-family:Courier
+         New;font-size:10.0pt;"><span style="color:green;">    // A
+         handy constant</span></span>
+      </p>
+      <p>
+         <span style="font-family:Courier
+         New;font-size:10.0pt;"><span style=
+         "color:blue;">    static</span> <span style=
+         "color:blue;">const</span> <span style=
+         "color:blue;">unsigned</span> <span style=
+         "color:black;">TRACE_CG</span> = <span style=
+         "color:black;">DBG_DUMP_BBS</span> | <span style= 
+         "color:black;">DBG_TRACE_CG</span> |</span>
+      </p>
+      <p>
+         <span style="font-family:Courier
+         New;font-size:10.0pt;"><span style=
+         "color:black;">                                     DBG_TRACE_LAYOUT</span>
+         | <span style="color:black;">DBG_TRACE_SUMM</span> |</span>
+      </p>
+      <p>
+         <span style="font-family:Courier
+         New;font-size:10.0pt;"><span style=
+         "color:black;">                                     DBG_DUMP_CODE</span>;</span>
+      </p>
+      <p>
+         <span style="font-family:Courier
+         New;font-size:10.0pt;"><span style="color:green;">    // For
+         methods in the range (1000;15000), print out the complete
+         code generator dumps</span></span>
+      </p>
+      <p>
+         <span style="font-family:Courier
+         New;font-size:10.0pt;"><span style=
+         "color:blue;">    if</span> (<span style=
+         "color:black;">g_methodsSeen</span>&gt;1000 &amp;&amp; <span
+         style="color:black;">g_methodsSeen</span>&lt;15000) {</span>
+      </p>
+      <p>
+         <span style="font-family:Courier
+         New;font-size:10.0pt;"><span style=
+         "color:black;">    compile_flags</span> |= <span style= 
+         "color:black;">TRACE_CG</span>;</span>
+      </p>
+      <p>
+         <span style="font-family:Courier
+         New;font-size:10.0pt;">    }</span>
+      </p>
+      <p>
+         <span style="font-family:Courier
+         New;font-size:10.0pt;"><span style="color:green;">    // For
+         methods getSomeValue() and for all methods in class
+         MyClass,</span></span>
+      </p>
+      <p>
+         <span style="font-family:Courier
+         New;font-size:10.0pt;"><span style="color:green;">    //
+         trace enter and exit</span></span>
+      </p>
+      <p>
+         <span style="font-family:Courier
+         New;font-size:10.0pt;"><span style=
+         "color:blue;">    if</span> (<span style=
+         "color:black;">NULL</span> != <span style=
+         "color:black;">strstr</span>(<span style=
+         "color:black;">m_fname</span>, "::getSomeValue") ||</span>
+      </p>
+      <p>
+         <span style="font-family:Courier
+         New;font-size:10.0pt;"><span style=
+         "color:black;">        NULL</span> != <span style= 
+         "color:black;">strstr</span>(<span style=
+         "color:black;">m_fname</span>, "MyClass::") ) {</span>
+      </p>
+      <p>
+         <span style="font-family:Courier
+         New;font-size:10.0pt;"><span style=
+         "color:black;">        compile_flags</span> |= <span style= 
+         "color:black;">    DBG_TRACE_EE</span>;</span>
+      </p>
+      <p>
+         <span style="font-family:Courier
+         New;font-size:10.0pt;">    }</span>
+      </p>
+      <p>
+         <span style="font-family:Courier
+         New;font-size:10.0pt;"><span style="color:green;">    // For
+         the method crashes_some_times() in class MyClass trace
+         every</span></span>
+      </p>
+      <p>
+         <span style="font-family:Courier
+         New;font-size:10.0pt;"><span style="color:green;">    //
+         bytecode execution: the last bytecode in the log is the most
+         probable</span></span>
+      </p>
+      <p>
+         <span style="font-family:Courier
+         New;font-size:10.0pt;"><span style="color:green;">    //
+         cause of the failure</span></span>
+      </p>
+      <p>
+         <span style="font-family:Courier
+         New;font-size:10.0pt;"><span style=
+         "color:blue;">    if</span> (!<span style=
+         "color:black;">strcmp</span>(<span style=
+         "color:black;">m_fname</span>,
+         "MyClass::crashes_some_times")) {</span>
+      </p>
+      <p>
+         <span style="font-family:Courier
+         New;font-size:10.0pt;"><span style=
+         "color:black;">        compile_flags</span> |= <span style= 
+         "color:black;">DBG_TRACE_EE</span>|<span style=
+         "color:black;">DBG_TRACE_BC</span>;</span>
+      </p>
+      <p>
+         <span style="font-family:Courier
+         New;font-size:10.0pt;">    }</span>
+      </p>
+      <p>
+         <span style="font-family:Courier
+         New;font-size:10.0pt;"><span style="color:green;">    //
+         Break into debugger (INT3) at the entry of the
+         stop_at_entry() method</span></span>
+      </p>
+      <p>
+         <span style="font-family:Courier
+         New;font-size:10.0pt;"><span style=
+         "color:blue;">    if</span> (!<span style=
+         "color:black;">strcmp</span>(<span style=
+         "color:black;">m_fname</span>, "MyClass::stop_at_entry"))
+         {</span>
+      </p>
+      <p>
+         <span style="font-family:Courier
+         New;font-size:10.0pt;"><span style=
+         "color:black;">        compile_flags</span> |= <span style= 
+         "color:black;">DBG_BRK</span>;</span>
+      </p>
+      <p>
+         <span style="font-family:Courier
+         New;font-size:10.0pt;">    }</span>
+      </p>
+      <p>
+         <span style="font-family:Courier
+         New;font-size:10.0pt;"><span style="color:green;">    //
+         Break into debugger (INT3) inside the method</span></span>
+      </p>
+      <p>
+         <span style="font-family:Courier
+         New;font-size:10.0pt;"><span style=
+         "color:blue;">    if</span> (!<span style=
+         "color:black;">strcmp</span>(<span style=
+         "color:black;">m_fname</span>,
+         "MyClass::stop_somewhere_in_the_middle")) {</span>
+      </p>
+      <p>
+         <span style="font-family:Courier
+         New;font-size:10.0pt;"><span style=
+         "color:black;">        dbg_break_pc</span> = 50;</span>
+      </p>
+      <p>
+         <span style="font-family:Courier
+         New;font-size:10.0pt;">    }</span>
+      </p>
+      <p>
+         <span style="font-family:Courier
+         New;font-size:10.0pt;"><span style="color:green;">    //
+         Trace run-time support calls: unwind, getting the address of
+         'this', root</span></span>
+      </p>
+      <p>
+         <span style="font-family:Courier
+         New;font-size:10.0pt;"><span style="color:green;">    // set
+         enumeration</span></span>
+      </p>
+      <p>
+         <span style="font-family:Courier
+         New;font-size:10.0pt;"><span style=
+         "color:blue;">    if</span> (!<span style=
+         "color:black;">strcmp</span>(<span style=
+         "color:black;">m_fname</span>,
+         "MyClass::something_wrong_with_unwind_here")) {</span>
+      </p>
+      <p>
+         <span style="font-family:Courier
+         New;font-size:10.0pt;"><span style=
+         "color:black;">        compile_flags</span> |= <span style= 
+         "color:black;">DBG_TRACE_RT</span>;</span>
+      </p>
+      <p>
+         <span style="font-family:Courier
+         New;font-size:10.0pt;">    }</span>
+      </p>
+      <p>
+         <span style="font-family:Courier
+         New;font-size:10.0pt;"><span style="color:green;">    //
+         By-pass run-time tracing for java/* classes</span></span>
+      </p>
+      <p>
+         <span style="font-family:Courier
+         New;font-size:10.0pt;"><span style=
+         "color:blue;">    if</span> (<span style=
+         "color:black;">m_fname</span> == <span style=
+         "color:black;">strstr</span>(<span style=
+         "color:black;">m_fname</span>, "java/")) {</span>
+      </p>
+      <p>
+         <span style="font-family:Courier
+         New;font-size:10.0pt;"><span style=
+         "color:black;">        compile_flags</span> &amp;= ~(<span
+         style="color:black;">DBG_TRACE_EE</span>|<span style= 
+         "color:black;">DBG_TRACE_BC</span>);</span>
+      </p>
+      <p>
+         <span style="font-family:Courier
+         New;font-size:10.0pt;">    }</span>
+      </p>
+      <p>
+         <span style="font-family:Courier 
+         New;font-size:10.0pt;color:blue;">#endif</span>
+      </p>
+      <p>
+          
+      </p>
+      <p>
+         <a href="#top">Back to top</a>
+      </p>
+      <p>
+         <a name="*"></a>* Other brands and names are the property of
+         their respective owners.
+      </p>
+   </body>
+</html>
+
 </div>
                                         </td>
                 </tr>



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