forked from OSchip/llvm-project
90 lines
3.3 KiB
ReStructuredText
90 lines
3.3 KiB
ReStructuredText
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.. raw:: html
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<style type="text/css">
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.none { background-color: #FFCCCC }
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.partial { background-color: #FFFF99 }
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.good { background-color: #CCFF99 }
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</style>
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.. role:: none
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.. role:: partial
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.. role:: good
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===============
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Windows support
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===============
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LLD has some experimental Windows support. When invoked as ``link.exe`` or with
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``-flavor link``, the driver for Windows operating system is used to parse
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command line options, and it drives further linking processes. LLD accepts
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almost all command line options that the linker shipped with Microsoft Visual
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C++ (link.exe) supports.
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The current status is that LLD can link itself on Windows x86 using Visual C++
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as the compiler.
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Development status
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==================
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Driver
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:good:`Mostly done`. Some exotic command line options that are not usually
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used for application develompent, such as ``/DRIVER``, are not supported.
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Options for Windows 8 app store are not recognized too
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(e.g. ``/APPCONTAINER``).
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Linking against DLL
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:good:`Done`. LLD can read import libraries needed to link against DLL. Both
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export-by-name and export-by-ordinal are supported.
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Linking against static library
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:good:`Done`. The format of static library (.lib) on Windows is actually the
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same as on Unix (.a). LLD can read it.
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Creating DLL
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:good:`Done`. LLD creates a DLL if ``/DLL`` option is given. Exported
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functions can be specified either via command line (``/EXPORT``) or via
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module-definition file (.def). Both export-by-name and export-by-ordinal are
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supported. LLD uses Microsoft ``lib.exe`` tool to create an import library
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file.
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Windows resource files support
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:good:`Done`. If an ``.rc`` file is given, LLD converts the file to a COFF
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file using some external commands and link it. Specifically, ``rc.exe`` is
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used to compile a resource file (.rc) to a compiled resource (.res)
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file. ``rescvt.exe`` is then used to convert a compiled resource file to a
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COFF object file section. Both tools are shipped with MSVC.
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Safe Structured Exception Handler (SEH)
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:good:`Done` for x86. :partial:`Work in progress` for x64.
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Module-definition file
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:partial:`Partially done`. LLD currently recognizes these directives:
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``EXPORTS``, ``HEAPSIZE``, ``STACKSIZE``, ``NAME``, and ``VERSION``.
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x64 (x86-64)
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:partial:`Work in progress`. LLD can create PE32+ executable but the generated
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file does not work unless source object files are very simple because of the
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lack of SEH handler table.
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Debug info
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:none:`No progress has been made`. Microsoft linker can interpret the CodeGen
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debug info (old-style debug info) and PDB to emit an .pdb file. LLD doesn't
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support neither.
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Known issues
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============
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Note that LLD is still in early stage in development, so there are still many
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bugs. Here is a list of notable bugs.
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* Symbol name resolution from library files sometimes fails. On Windows, the
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order of library files in command line does not matter, but LLD sometimes
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fails to simulate the semantics. A workaround for it is to explicitly add
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library files to command line with ``/DEFAULTLIB``.
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* Subsystem inference is not very reliable. Linker is supposed to set
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``subsystem`` field in the PE/COFF header according to entry function name,
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but LLD sometimes ended up with ``unknown`` subsystem type. You need to give
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``/SUBSYSTEM`` option if it fails to infer it.
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