<ol>
<li><a href="#libraries">Libraries</a>
<ol>
- <li><a href="#Modules">Bytecode Modules</a></li>
+ <li><a href="#BCModules">Bytecode Modules</a></li>
+ <li><a href="#LoadableModules">Loadable Modules</a></li>
</ol>
</li>
<li><a href="#tools">Tools</a>
LIBRARYNAME = mylib
SHARED_LIBRARY = 1
ARCHIVE_LIBRARY = 1
- DONT_BUILT_RELINKED = 1
+ DONT_BUILD_RELINKED = 1
</tt></pre>
<p>says to build a library named "mylib" with both a shared library
(<tt>mylib.so</tt>) and an archive library (<tt>mylib.a</tt>) version but
</div>
<!-- ======================================================================= -->
-<div class="doc_subsubsection"><a name="Modules">Bytecode Modules</a></div>
+<div class="doc_subsubsection"><a name="BCModules">Bytecode Modules</a></div>
<div class="doc_text">
<p>In some situations, it is desireable to build a single bytecode module from
a variety of sources, instead of an archive, shared library, or bytecode
</p>
</div>
+<!-- ======================================================================= -->
+<div class="doc_subsubsection">
+ <a name="LoadableModules">Loadable Modules</a>
+</div>
+<div class="doc_text">
+ <p>In some situations, you need to create a loadable module. Loadable modules
+ can be loaded into programs like <tt>opt</tt> or <tt>llc</tt> to specify
+ additional passes to run or targets to support. Loadable modules are also
+ useful for debugging a pass or providing a pass with another package if that
+ pass can't be included in LLVM.</p>
+ <p>LLVM provides complete support for building such a module. All you need to
+ do is use the LOADABLE_MODULE variable in your Makefile. For example, to
+ build a loadable module named <tt>MyMod</tt> that uses the LLVM libraries
+ <tt>LLVMSupport.a</tt> and <tt>LLVMSystem.a</tt>, you would specify:</p>
+ <pre><tt>
+ LIBRARYNAME := MyMod
+ LOADABLE_MODULE := 1
+ LINK_COMPONENTS := support system
+ </tt></pre>
+ <p>Use of the <tt>LOADABLE_MODULE</tt> facility implies several things:</p>
+ <ol>
+ <li>There will be no "lib" prefix on the module. This differentiates it from
+ a standard shared library of the same name.</li>
+ <li>The <a href="#SHARED_LIBRARY">SHARED_LIBRARY</a> variable is turned
+ on.</li>
+ <li>The <a href="#LINK_LIBS_IN_SHARED">LINK_LIBS_IN_SHARED</a> variable
+ is turned on.</li>
+ <li>The <a href="#DONT_BUILD_RELINKED">DONT_BUILD_RELINKED</a> variable
+ is turned on.</li>
+ </ol>
+ <p>A loadable module is loaded by LLVM via the facilities of libtool's libltdl
+ library which is part of <tt>lib/System</tt> implementation.</p>
+</div>
+
<!-- ======================================================================= -->
<div class="doc_subsection"><a name="tools">Tools</a></div>
<div class="doc_text">
<pre><tt>
TOOLNAME = mytool
USEDLIBS = mylib
- LLVMLIBS = LLVMSupport.a LLVMSystem.a
+ LINK_COMPONENTS = support system
</tt></pre>
<p>says that we are to build a tool name <tt>mytool</tt> and that it requires
three libraries: <tt>mylib</tt>, <tt>LLVMSupport.a</tt> and
<!-- ======================================================================= -->
<div class="doc_subsubsection"><a name="JIT">JIT Tools</a></div>
<div class="doc_text">
- <p>Many tools will want to use the JIT features of LLVM. However, getting the
- right set of libraries to link with is tedious, platform specific, and error
- prone. Additionally, the JIT has special linker switch options that it needs.
- Consequently, to make it easier to build tools that use the JIT, you can
- use a special value for the <tt>LLVMLIBS</tt> variable:</p>
+ <p>Many tools will want to use the JIT features of LLVM. To do this, you
+ simply specify that you want an execution 'engine', and the makefiles will
+ automatically link in the appropriate JIT for the host or an interpreter
+ if none is available:</p>
<pre><tt>
TOOLNAME = my_jit_tool
USEDLIBS = mylib
- LLVMLIBS = JIT
+ LINK_COMPONENTS = engine
</tt></pre>
- <p>Using a value of <tt>JIT</tt> for <tt>LLVMLIBS</tt> tells the makefile
- system to construct a special value for LLVMLIBS that gives the program all
- the LLVM libraries needed to run the JIT. Any additional libraries needed can
- still be specified with <tt>USEDLIBS</tt>. To get a full understanding of how
- this changes the linker command, it is recommended that you:</p>
+ <p>Of course, any additional libraries may be listed as other components. To
+ get a full understanding of how this changes the linker command, it is
+ recommended that you:</p>
<pre><tt>
cd examples/Fibonacci
make VERBOSE=1
</tt></pre>
- <p>By default, using <tt>LLVMLIBS=JIT</tt> will link in enough to support JIT
- code generation for the architecture on which the tool is linked. If you need
- additional target architectures linked in, you may specify them on the command
- line or in your <tt>Makefile</tt>. For example:</p>
- <pre><tt>
- ENABLE_X86_JIT=1
- ENABLE_SPARCV9_JIT=1
- ENALBE_PPC_JIT=1
- </tt></pre>
- <p>will cause the tool to be able to generate code for all three platforms.
- </p>
</div>
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