docs/CommandGuide/gccld.html - platform/external/llvm - Gitiles

 <html>
 <title>LLVM: gccld tool</title>

 <body bgcolor=white>

 <center><h1>LLVM: <tt>gccld</tt> tool</h1></center>
 <HR>

 <h3>NAME</h3>
 <tt>gccld</tt>

 <h3>SYNOPSIS</h3>
 <tt>gccld [options] &lt; filename&gt; [ filename ...]</tt>

 <h3>DESCRIPTION</h3>

 The <tt>gccld</tt> utility takes a set of LLVM bytecode files and links them
 together into a single LLVM bytecode file.  The output bytecode file can be
 another bytecode library or an executable bytecode program.  Using additional
 options, <tt>gccld</tt> is able to produce native code executables.
 <p>

 The <tt>gccld</tt> utility is primarily used by the <a href="llvmgcc.html">C</a>
 and <a href="llvmgxx.html">C++</a> front-ends, and as such, attempts to mimic
 the interface provided by the default system linker so that it can act as a
 "drop-in" replacement.
 <p>

 The <tt>gccld</tt> tool performs a small set of interprocedural, post-link,
 optimizations on the program.


 <h4>Search Order</h4>

 <p>
 When looking for objects specified on the command line, <tt>gccld</tt> will
 search for the object first in the current directory and then in the directory
 specified by the <tt>LLVM_LIB_SEARCH_PATH</tt> environment variable.  If it
 cannot find the object, it fails.
 </p>

 <p>
 When looking for a library specified with the -l option, <tt>gccld</tt> first
 attempts to load a file with that name from the current directory.  If that
 fails, it looks for lib&lt;library&gt;.bc, lib&lt;library&gt;.a, or
 lib&lt;library&gt;.&lt;shared library extension&gt;, in that order, in each
 directory added to the library search path with the -L option.  These
 directories are searched in the order they
 were specified.  If the library cannot be located, then <tt>gccld</tt> looks in
 the directory specified by the <tt>LLVM_LIB_SEARCH_PATH</tt> environment
 variable.  If it does not find a library there, it fails.
 </p>

 <p>
 The shared library extension is usually <tt>.so</tt>, but it may differ
 depending upon the system.
 </p>

 <p>
 The -L option is global.  It does not matter where it is specified in the list
 of command line arguments; the directory is simply added to the search path and
 is applied to all libraries, preceding or succeeding, in the command line.
 </p>

 <h4>Link order</h4>

 All object files are linked first in the order they were specified on the
 command line.  All library files are linked next.  Some libraries may not be
 linked into the object program; see below.

 <h4>Library Linkage</h4>

 Object files and static bytecode objects are always linked into the output
 file.  Library archives (.a files) load only the objects within the archive
 that define symbols needed by the output file.  Hence, libraries should be
 listed after the object files and libraries which need them; otherwise, the
 library may not be linked in, and the dependent library will not have its
 undefined symbols defined.

 <h4>Native code generation</h4>

 The <tt>gccld</tt> program has limited support for native code generation, when
 using the -native option.


 <h3>OPTIONS</h3>

 <ul>
 	<li> -help
 	<br>
 	Print a summary of command line options.
 	<p>

 	<li> -o &lt;filename&gt;
 	<br>
 	Specify the output filename which will hold the linked bytecode.
 	<p>

 	<li> -stats
 	<br>
 	Print statistics.
 	<p>

 	<li> -time-passes
 	<br>
 	Record the amount of time needed for each pass and print it to standard
 	error.
 	<p>

 	<li> -verify
 	<br>
 	Verify each pass result.
 	<p>

 	<li> -disable-opt
 	<br>
     Disable all link-time optimization passes.
 	<p>

 	<li> -L=&lt;directory&gt;
 	<br>
 	Add directory to the list of directories to search when looking for
 	libraries.
 	<p>

 	<li> -disable-internalize
 	<br>
 	Do not mark all symbols as internal.
 	<p>

 	<li> -internalize-public-api-file &lt;filename&gt;
 	<br>
 	Preserve the list of symbol names in the file filename.
 	<p>

 	<li> -internalize-public-api-list &lt;list&gt;
 	<br>
 	Preserve the symbol names in list.
 	<p>

 	<li> -l=&lt;library&gt;
 	<br>
 	Specify libraries to include when linking the output file.  When
 	linking, <tt>gccld</tt> will first attempt to load a file with the
 	pathname <tt>library</tt>.  If that fails, it will then attempt to load
 	lib&lt;library&gt;.bc, lib&lt;library&gt;.a, and
   lib&lt;library&gt;.&lt;shared library extension&gt;, in that order.
 	<p>

 	<li> -link-as-library
 	<br>
 	Link the .bc files together as a library, not an executable.
 	<p>

 	<li> -native
 	<br>
 	Generate a native, machine code executable.
   <p>
   When generating native executables, <tt>gccld</tt> first checks for a bytecode
   version of the library and links it in, if necessary.  If the library is
   missing, <tt>gccld</tt> skips it.  Then, <tt>gccld</tt> links in the same
   libraries as native code.
   <p>
   In this way, <tt>gccld</tt> should be able to link in optimized bytecode
   subsets of common libraries and then link in any part of the library that
   hasn't been converted to bytecode.
 	<p>

 	<li> -s
 	<br>
 	Strip symbol information from the generated executable.
 	<p>

 	<li> -v
 	<br>
 	Print information about actions taken.
 </ul>

 <h3>EXIT STATUS</h3>

 If <tt>gccld</tt> succeeds, it will exit with 0.  Otherwise, if an error occurs,
 it will exit with a non-zero value.

 <h3>SEE ALSO</h3>
 <a href="llvm-link.html"><tt>llvm-link</tt></a>
 <a href="gccas.html"><tt>gccas</tt></a>

 <h3>BUGS</h3>
 The -L option cannot be used for find native code libraries when using the
 -native option.

 <HR>
 Maintained by the <a href="http://llvm.cs.uiuc.edu">LLVM Team</a>.
 </body>
 </html>
	<html>
	<title>LLVM: gccld tool</title>

	<body bgcolor=white>

	<center><h1>LLVM: <tt>gccld</tt> tool</h1></center>
	<HR>

	<h3>NAME</h3>
	<tt>gccld</tt>

	<h3>SYNOPSIS</h3>
	<tt>gccld [options] < filename> [ filename ...]</tt>

	<h3>DESCRIPTION</h3>

	The <tt>gccld</tt> utility takes a set of LLVM bytecode files and links them
	together into a single LLVM bytecode file. The output bytecode file can be
	another bytecode library or an executable bytecode program. Using additional
	options, <tt>gccld</tt> is able to produce native code executables.
	<p>

	The <tt>gccld</tt> utility is primarily used by the <a href="llvmgcc.html">C</a>
	and <a href="llvmgxx.html">C++</a> front-ends, and as such, attempts to mimic
	the interface provided by the default system linker so that it can act as a
	"drop-in" replacement.
	<p>

	The <tt>gccld</tt> tool performs a small set of interprocedural, post-link,
	optimizations on the program.


	<h4>Search Order</h4>

	<p>
	When looking for objects specified on the command line, <tt>gccld</tt> will
	search for the object first in the current directory and then in the directory
	specified by the <tt>LLVM_LIB_SEARCH_PATH</tt> environment variable. If it
	cannot find the object, it fails.
	</p>

	<p>
	When looking for a library specified with the -l option, <tt>gccld</tt> first
	attempts to load a file with that name from the current directory. If that
	fails, it looks for lib<library>.bc, lib<library>.a, or
	lib<library>.<shared library extension>, in that order, in each
	directory added to the library search path with the -L option. These
	directories are searched in the order they
	were specified. If the library cannot be located, then <tt>gccld</tt> looks in
	the directory specified by the <tt>LLVM_LIB_SEARCH_PATH</tt> environment
	variable. If it does not find a library there, it fails.
	</p>

	<p>
	The shared library extension is usually <tt>.so</tt>, but it may differ
	depending upon the system.
	</p>

	<p>
	The -L option is global. It does not matter where it is specified in the list
	of command line arguments; the directory is simply added to the search path and
	is applied to all libraries, preceding or succeeding, in the command line.
	</p>

	<h4>Link order</h4>

	All object files are linked first in the order they were specified on the
	command line. All library files are linked next. Some libraries may not be
	linked into the object program; see below.

	<h4>Library Linkage</h4>

	Object files and static bytecode objects are always linked into the output
	file. Library archives (.a files) load only the objects within the archive
	that define symbols needed by the output file. Hence, libraries should be
	listed after the object files and libraries which need them; otherwise, the
	library may not be linked in, and the dependent library will not have its
	undefined symbols defined.

	<h4>Native code generation</h4>

	The <tt>gccld</tt> program has limited support for native code generation, when
	using the -native option.


	<h3>OPTIONS</h3>

	<ul>
	<li> -help
	<br>
	Print a summary of command line options.
	<p>

	<li> -o <filename>
	<br>
	Specify the output filename which will hold the linked bytecode.
	<p>

	<li> -stats
	<br>
	Print statistics.
	<p>

	<li> -time-passes
	<br>
	Record the amount of time needed for each pass and print it to standard
	error.
	<p>

	<li> -verify
	<br>
	Verify each pass result.
	<p>

	<li> -disable-opt
	<br>
	Disable all link-time optimization passes.
	<p>

	<li> -L=<directory>
	<br>
	Add directory to the list of directories to search when looking for
	libraries.
	<p>

	<li> -disable-internalize
	<br>
	Do not mark all symbols as internal.
	<p>

	<li> -internalize-public-api-file <filename>
	<br>
	Preserve the list of symbol names in the file filename.
	<p>

	<li> -internalize-public-api-list <list>
	<br>
	Preserve the symbol names in list.
	<p>

	<li> -l=<library>
	<br>
	Specify libraries to include when linking the output file. When
	linking, <tt>gccld</tt> will first attempt to load a file with the
	pathname <tt>library</tt>. If that fails, it will then attempt to load
	lib<library>.bc, lib<library>.a, and
	lib<library>.<shared library extension>, in that order.
	<p>

	<li> -link-as-library
	<br>
	Link the .bc files together as a library, not an executable.
	<p>

	<li> -native
	<br>
	Generate a native, machine code executable.
	<p>
	When generating native executables, <tt>gccld</tt> first checks for a bytecode
	version of the library and links it in, if necessary. If the library is
	missing, <tt>gccld</tt> skips it. Then, <tt>gccld</tt> links in the same
	libraries as native code.
	<p>
	In this way, <tt>gccld</tt> should be able to link in optimized bytecode
	subsets of common libraries and then link in any part of the library that
	hasn't been converted to bytecode.
	<p>

	<li> -s
	<br>
	Strip symbol information from the generated executable.
	<p>

	<li> -v
	<br>
	Print information about actions taken.
	</ul>

	<h3>EXIT STATUS</h3>

	If <tt>gccld</tt> succeeds, it will exit with 0. Otherwise, if an error occurs,
	it will exit with a non-zero value.

	<h3>SEE ALSO</h3>
	<a href="llvm-link.html"><tt>llvm-link</tt></a>
	<a href="gccas.html"><tt>gccas</tt></a>

	<h3>BUGS</h3>
	The -L option cannot be used for find native code libraries when using the
	-native option.

	<HR>
	Maintained by the <a href="http://llvm.cs.uiuc.edu">LLVM Team</a>.
	</body>
	</html>