mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2025-11-04 05:17:07 +00:00
d7de7bc297
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@76768 91177308-0d34-0410-b5e6-96231b3b80d8
235 lines
6.9 KiB
Plaintext
235 lines
6.9 KiB
Plaintext
=pod
|
|
|
|
=head1 NAME
|
|
|
|
llvm-ld - LLVM linker
|
|
|
|
=head1 SYNOPSIS
|
|
|
|
B<llvm-ld> <options> <files>
|
|
|
|
=head1 DESCRIPTION
|
|
|
|
The B<llvm-ld> tool takes a set of LLVM bitcode files and links them
|
|
together into a single LLVM bitcode file. The output bitcode file can be
|
|
another bitcode file or an executable bitcode program. Using additional
|
|
options, B<llvm-ld> is able to produce native code executables.
|
|
|
|
The B<llvm-ld> tool is the main linker for LLVM. It is used to link together
|
|
the output of LLVM front-end compilers and run "link time" optimizations (mostly
|
|
the inter-procedural kind).
|
|
|
|
The B<llvm-ld> tools attempts to mimic the interface provided by the default
|
|
system linker so that it can act as a I<drop-in> replacement.
|
|
|
|
=head2 Search Order
|
|
|
|
When looking for objects specified on the command line, B<llvm-ld> will search
|
|
for the object first in the current directory and then in the directory
|
|
specified by the B<LLVM_LIB_SEARCH_PATH> environment variable. If it cannot
|
|
find the object, it fails.
|
|
|
|
When looking for a library specified with the B<-l> option, B<llvm-ld> first
|
|
attempts to load a file with that name from the current directory. If that
|
|
fails, it looks for libI<library>.bc, libI<library>.a, or libI<library>.I<shared
|
|
library extension>, in that order, in each directory added to the library search
|
|
path with the B<-L> option. These directories are searched in the order they
|
|
are specified. If the library cannot be located, then B<llvm-ld> looks in the
|
|
directory specified by the B<LLVM_LIB_SEARCH_PATH> environment variable. If it
|
|
does not find a library there, it fails.
|
|
|
|
The I<shared library extension> may be I<.so>, I<.dyld>, I<.dll>, or something
|
|
different, depending upon the system.
|
|
|
|
The B<-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.
|
|
|
|
=head2 Link order
|
|
|
|
All object and bitcode 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.
|
|
|
|
=head2 Library Linkage
|
|
|
|
Object files and static bitcode 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.
|
|
|
|
=head2 Native code generation
|
|
|
|
The B<llvm-ld> program has limited support for native code generation, when
|
|
using the B<-native> or B<-native-cbe> options. Native code generation is
|
|
performed by converting the linked bitcode into native assembly (.s) or C code
|
|
and running the system compiler (typically gcc) on the result.
|
|
|
|
=head1 OPTIONS
|
|
|
|
=head2 General Options
|
|
|
|
=over
|
|
|
|
=item B<-help>
|
|
|
|
Print a summary of command line options.
|
|
|
|
=item B<-v>
|
|
|
|
Specifies verbose mode. In this mode the linker will print additional
|
|
information about the actions it takes, programs it executes, etc.
|
|
|
|
=item B<-stats>
|
|
|
|
Print statistics.
|
|
|
|
=item B<-time-passes>
|
|
|
|
Record the amount of time needed for each pass and print it to standard
|
|
error.
|
|
|
|
=back
|
|
|
|
=head2 Input/Output Options
|
|
|
|
=over
|
|
|
|
=item B<-o> F<filename>
|
|
|
|
This overrides the default output file and specifies the name of the file that
|
|
should be generated by the linker. By default, B<llvm-ld> generates a file named
|
|
F<a.out> for compatibility with B<ld>. The output will be written to
|
|
F<filename>.
|
|
|
|
=item B<-b> F<filename>
|
|
|
|
This option can be used to override the output bitcode file name. By default,
|
|
the name of the bitcode output file is one more ".bc" suffix added to the name
|
|
specified by B<-o filename> option.
|
|
|
|
=item B<-l>F<name>
|
|
|
|
This option specifies the F<name> of a library to search when resolving symbols
|
|
for the program. Only the base name should be specified as F<name>, without a
|
|
F<lib> prefix or any suffix.
|
|
|
|
=item B<-L>F<Path>
|
|
|
|
This option tells B<llvm-ld> to look in F<Path> to find any library subsequently
|
|
specified with the B<-l> option. The paths will be searched in the order in
|
|
which they are specified on the command line. If the library is still not found,
|
|
a small set of system specific directories will also be searched. Note that
|
|
libraries specified with the B<-l> option that occur I<before> any B<-L> options
|
|
will not search the paths given by the B<-L> options following it.
|
|
|
|
=item B<-link-as-library>
|
|
|
|
Link the bitcode files together as a library, not an executable. In this mode,
|
|
undefined symbols will be permitted.
|
|
|
|
=item B<-r>
|
|
|
|
An alias for -link-as-library.
|
|
|
|
=item B<-native>
|
|
|
|
Generate a native machine code executable.
|
|
|
|
When generating native executables, B<llvm-ld> first checks for a bitcode
|
|
version of the library and links it in, if necessary. If the library is
|
|
missing, B<llvm-ld> skips it. Then, B<llvm-ld> links in the same
|
|
libraries as native code.
|
|
|
|
In this way, B<llvm-ld> should be able to link in optimized bitcode
|
|
subsets of common libraries and then link in any part of the library that
|
|
hasn't been converted to bitcode.
|
|
|
|
=item B<-native-cbe>
|
|
|
|
Generate a native machine code executable with the LLVM C backend.
|
|
|
|
This option is identical to the B<-native> option, but uses the
|
|
C backend to generate code for the program instead of an LLVM native
|
|
code generator.
|
|
|
|
=back
|
|
|
|
=head2 Optimization Options
|
|
|
|
=over
|
|
|
|
=item B<-disable-inlining>
|
|
|
|
Do not run the inlining pass. Functions will not be inlined into other
|
|
functions.
|
|
|
|
=item B<-disable-opt>
|
|
|
|
Completely disable optimization.
|
|
|
|
=item B<-disable-internalize>
|
|
|
|
Do not mark all symbols as internal.
|
|
|
|
=item B<-verify-each>
|
|
|
|
Run the verification pass after each of the passes to verify intermediate
|
|
results.
|
|
|
|
=item B<-strip-all>
|
|
|
|
Strip all debug and symbol information from the executable to make it smaller.
|
|
|
|
=item B<-strip-debug>
|
|
|
|
Strip all debug information from the executable to make it smaller.
|
|
|
|
=item B<-s>
|
|
|
|
An alias for B<-strip-all>.
|
|
|
|
=item B<-S>
|
|
|
|
An alias for B<-strip-debug>.
|
|
|
|
=item B<-export-dynamic>
|
|
|
|
An alias for B<-disable-internalize>
|
|
|
|
=item B<-post-link-opt>F<Path>
|
|
|
|
Run post-link optimization program. After linking is completed a bitcode file
|
|
will be generated. It will be passed to the program specified by F<Path> as the
|
|
first argument. The second argument to the program will be the name of a
|
|
temporary file into which the program should place its optimized output. For
|
|
example, the "no-op optimization" would be a simple shell script:
|
|
|
|
#!/bin/bash
|
|
cp $1 $2
|
|
|
|
=back
|
|
|
|
=head1 EXIT STATUS
|
|
|
|
If B<llvm-ld> succeeds, it will exit with 0 return code. If an error occurs,
|
|
it will exit with a non-zero return code.
|
|
|
|
=head1 ENVIRONMENT
|
|
|
|
The C<LLVM_LIB_SEARCH_PATH> environment variable is used to find bitcode
|
|
libraries. Any paths specified in this variable will be searched after the C<-L>
|
|
options.
|
|
|
|
=head1 SEE ALSO
|
|
|
|
L<llvm-link|llvm-link>
|
|
|
|
=head1 AUTHORS
|
|
|
|
Maintained by the LLVM Team (L<http://llvm.org>).
|
|
|
|
=cut
|