hotspot/agent/doc/clhsdb.html

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Command line HSDB
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<h1>Command line HSDB</h1>
<p>
When debugging remote core dumps it is easier to work with command line tools instead of
GUI tools. Command line HSDB (CLHSDB) tool is alternative to SA GUI tool HSDB.
</p>

<p>
There is also JavaScript based SA command line interface called <a href="jsdb.html">jsdb</a>.
But, CLHSDB supports Unix shell-like (or dbx/gdb-like) command line interface with
support for output redirection/appending (familiar &gt;, &gt;&gt;), command history and so on.
Each CLHSDB command can have zero or more arguments and optionally end with output redirection
(or append) to a file. Commands may be stored in a file and run using <b>source</b> command.
<b>help</b> command prints usage message for all supported commands (or a specific command)
</p>

<h3>Shell/batch scripts to run command line HSDB</h3>

<ul>
<li>clhsdbproc.sh
<li>clhsdbproc64.sh
<li>clhsdbwindbg.bat
<li>clhsdbwindbg64.bat
</ul>

<h3>Annotated output of CLHSDB help command</h3>

<pre>
<code>
Available commands:
  assert true | false <font color="red">turn on/off asserts in SA code</font>
  attach pid | exec core  <font color="red">attach SA to a process or core</font>
  buildreplayjars [all | boot | app] <font color="red">build jars for replay, boot.jar for bootclasses, app.jar for application classes</font>
  class name <font color="red">find a Java class from debuggee and print oop</font>
  classes <font color="red">print all loaded Java classes with Klass*</font>
  detach <font color="red">detach SA from current target</font>
  dis address [ length ]  <font color="red">disassemble (sparc/x86) specified number of instructions from given address</font>
  dissemble address <font color="red">disassemble nmethod</font>
  dumpcfg -a | id <font color="red">Dump the PhaseCFG for every compiler thread that has one live</font>
  dumpclass { address | name } [ directory ] <font color="red">dump .class file for given Klass* or class name</font>
  dumpcodecache <font color="red">dump codecache contents</font>
  dumpheap [ file ] <font color="red">dump heap in hprof binary format</font>
  dumpideal -a | id <font color="red">dump ideal graph like debug flag -XX:+PrintIdeal</font>
  dumpilt -a | id <font color="red">dump inline tree for C2 compilation</font>
  dumpreplaydata &lt;address&gt; | -a | &lt;thread_id&gt; [&gt;replay.txt] <font color="red">dump replay data into a file</font>
  echo [ true | false ] <font color="red">turn on/off command echo mode</font>
  examine [ address/count ] | [ address,address] <font color="red">show contents of memory from given address</font>
  field [ type [ name fieldtype isStatic offset address ] ] <font color="red">print info about a field of HotSpot type</font>
  findpc address <font color="red">print info. about pointer location</font>
  flags [ flag ] <font color="red">show all -XX flag name value pairs. or just show given flag</font>
  help [ command ] <font color="red">print help message for all commands or just given command</font>
  history <font color="red">show command history. usual !command-number syntax works.</font>
  inspect expression <font color="red">inspect a given oop</font>
  intConstant [ name [ value ] ] <font color="red">print out hotspot integer constant(s)</font>
  jdis address <font color="red">show bytecode disassembly of a given Method*</font>
  jhisto <font color="red">show Java heap histogram</font>
  jseval script <font color="red">evaluate a given string as JavaScript code</font>
  jsload file <font color="red">load and evaluate a JavaScript file</font>
  jstack [-v] <font color="red">show Java stack trace of all Java threads. -v is verbose mode</font>
  livenmethods <font color="red">show all live nmethods</font>
  longConstant [ name [ value ] ] <font color="red">print out hotspot long constant(s)s</font>
  mem address [ length ] <font color="red">show contents of memory -- also shows closest ELF/COFF symbol if found</font>
  pmap <font color="red">show Solaris pmap-like output</font>
  print expression <font color="red">print given Klass*, Method* or arbitrary address</font>
  printas type expression <font color="red">print given address as given HotSpot type. eg. print JavaThread &lt;address&gt;</font>
  printmdo -a | expression <font color="red">print method data oop</font>
  printstatics [ type ] <font color="red">print static fields of given HotSpot type (or all types if none specified)</font>
  pstack [-v] <font color="red">show mixed mode stack trace for all Java, non-Java threads. -v is verbose mode</font>
  quit <font color="red">quit CLHSDB tool</font>
  reattach <font color="red">detach and re-attach SA to current target</font>
  revptrs  <font color="red">find liveness of oops</font>
  scanoops start end [ type ] <font color="red">scan a Oop from given start to end address</font>
  search [ heap | codecache | threads ] value <font color="red">search a value in heap or codecache or threads</font>
  source filename <font color="red">load and execute CLHSDB commands from given file</font>
  symbol name <font color="red">show address of a given ELF/COFF symbol</font>
  sysprops <font color="red">show all Java System properties</font>
  thread id <font color="red">show thread of id</font>
  threads <font color="red">show all Java threads</font>
  tokenize ...
  type [ type [ name super isOop isInteger isUnsigned size ] ] <font color="red">show info. on HotSpot type</font>
  universe <font color="red">print gc universe</font>
  vmstructsdump <font color="red">dump hotspot type library in text</font>
  verbose true | false <font color="red">turn on/off verbose mode</font>
  versioncheck [ true | false ] <font color="red">turn on/off debuggee VM version check</font>
  whatis address <font color="red">print info about any arbitrary address</font>
  where { -a | id } <font color="red">print Java stack trace of given Java thread or all Java threads (-a)</font>
</code>
</pre>

<h3>JavaScript integration</h3>

<p>Few CLHSDB commands are already implemented in JavaScript. It is possible to extend CLHSDB command set
by implementing more commands in a JavaScript file and by loading it by <b>jsload</b> command. <b>jseval</b>
command may be used to evaluate arbitrary JavaScript expression from a string. Any JavaScript function
may be exposed as a CLHSDB command by registering it using JavaScript <b><code>registerCommand</code></b>
function. This function accepts command name, usage and name of the JavaScript implementation function
as arguments.
</p>

<h3>Simple CLHSDB command implemented in JavaScript</h3>

<b>File: test.js</b>
<pre>
<code>
function helloImpl(name) {
    println("hello, " + name);
}

// register the above JavaScript function as CLHSDB command
registerCommand("hello", "hello name", "helloImpl");
</code>
</pre>
---------<br>

"test.js" can be loaded in CLHSDB prompt using <b>jsload</b> command using

<pre>
<code>
hsdb&gt; jsload test.js
</code>
</pre>

<h3>Compilation Replay</h3>
<p>
When a java process crashes in compiled method, usually a core file is saved.
The replay function can reproduce the compiling process in the core.
<a href="cireplay.html">cireplay.html</a>

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