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* Add the use of LOADABLE_MODULE=1 in the makefile example 

* Change the names of the resulting module to Hello instead of libHello
* Change lib/Debug -> Debug/lib per new makefile implementation.

llvm-svn: 19459
This commit is contained in:
Reid Spencer 2005-01-11 05:16:23 +00:00
parent 1e008c200d
commit 4a1ab18fbf
1 changed files with 18 additions and 13 deletions
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31
llvm/docs/WritingAnLLVMPass.html
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@ -2,6 +2,7 @@
"http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>Writing an LLVM Pass</title>
<link rel="stylesheet" href="llvm.css" type="text/css">
</head>
@ -169,21 +170,25 @@ source tree in the <tt>lib/Transforms/Hello</tt> directory.</p>
LEVEL = ../../..
# Name of the library to build
LIBRARYNAME = hello
LIBRARYNAME = Hello
# Build a dynamically loadable shared object
# Build a dynamically linkable shared object
SHARED_LIBRARY = 1
# Make the shared library become a loadable module so the tools can
# dlopen/dlsym on the resulting library.
LOADABLE_MODULE
# Include the makefile implementation stuff
include $(LEVEL)/Makefile.common
</pre>
<p>This makefile specifies that all of the <tt>.cpp</tt> files in the current
directory are to be compiled and linked together into a
<tt>lib/Debug/libhello.so</tt> shared object that can be dynamically loaded by
the <tt>opt</tt> or <tt>analyze</tt> tools. If your operating system uses a
suffix other than .so (such as windows or Mac OS/X), the appropriate extension
will be used.</p>
<tt>Debug/lib/Hello.so</tt> shared object that can be dynamically loaded by
the <tt>opt</tt> or <tt>analyze</tt> tools via their <tt>-load</tt> options.
If your operating system uses a suffix other than .so (such as windows or
Mac OS/X), the appropriate extension will be used.</p>
<p>Now that we have the build scripts set up, we just need to write the code for
the pass itself.</p>
@ -290,7 +295,7 @@ depending on what it is to be used for. For "optimizations" we use the
<p>Now that it's all together, compile the file with a simple "<tt>gmake</tt>"
command in the local directory and you should get a new
"<tt>lib/Debug/libhello.so</tt> file. Note that everything in this file is
"<tt>Debug/lib/Hello.so</tt> file. Note that everything in this file is
contained in an anonymous namespace: this reflects the fact that passes are self
contained units that do not need external interfaces (although they can have
them) to be useful.</p>
@ -316,7 +321,7 @@ through our transformation like this (or course, any bytecode file will
work):</p>
<pre>
$ opt -load ../../../lib/Debug/libhello.so -hello &lt; hello.bc &gt; /dev/null
$ opt -load ../../../Debug/lib/Hello.so -hello &lt; hello.bc &gt; /dev/null
Hello: __main
Hello: puts
Hello: main
@ -333,7 +338,7 @@ interesting way, we just throw away the result of <tt>opt</tt> (sending it to
<tt>opt</tt> with the <tt>--help</tt> option:</p>
<pre>
$ opt -load ../../../lib/Debug/libhello.so --help
$ opt -load ../../../Debug/lib/Hello.so --help
OVERVIEW: llvm .bc -&gt; .bc modular optimizer
USAGE: opt [options] &lt;input bytecode&gt;
@ -361,7 +366,7 @@ the execution time of your pass along with the other passes you queue up. For
example:</p>
<pre>
$ opt -load ../../../lib/Debug/libhello.so -hello -time-passes &lt; hello.bc &gt; /dev/null
$ opt -load ../../../Debug/lib/Hello.so -hello -time-passes &lt; hello.bc &gt; /dev/null
Hello: __main
Hello: puts
Hello: main
@ -1286,7 +1291,7 @@ how our <a href="#basiccode">Hello World</a> pass interacts with other passes.
Lets try it out with the <tt>gcse</tt> and <tt>licm</tt> passes:</p>
<pre>
$ opt -load ../../../lib/Debug/libhello.so -gcse -licm --debug-pass=Structure &lt; hello.bc &gt; /dev/null
$ opt -load ../../../Debug/lib/Hello.so -gcse -licm --debug-pass=Structure &lt; hello.bc &gt; /dev/null
Module Pass Manager
Function Pass Manager
Dominator Set Construction
@ -1323,7 +1328,7 @@ passes.</p>
World</a> pass in between the two passes:</p>
<pre>
$ opt -load ../../../lib/Debug/libhello.so -gcse -hello -licm --debug-pass=Structure &lt; hello.bc &gt; /dev/null
$ opt -load ../../../Debug/lib/Hello.so -gcse -hello -licm --debug-pass=Structure &lt; hello.bc &gt; /dev/null
Module Pass Manager
Function Pass Manager
Dominator Set Construction
@ -1364,7 +1369,7 @@ href="#getAnalysisUsage"><tt>getAnalysisUsage</tt></a> method to our pass:</p>
<p>Now when we run our pass, we get this output:</p>
<pre>
$ opt -load ../../../lib/Debug/libhello.so -gcse -hello -licm --debug-pass=Structure &lt; hello.bc &gt; /dev/null
$ opt -load ../../../Debug/lib/Hello.so -gcse -hello -licm --debug-pass=Structure &lt; hello.bc &gt; /dev/null
Pass Arguments: -gcse -hello -licm
Module Pass Manager
Function Pass Manager