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Diffstat (limited to 'docs/WritingAnLLVMBackend.rst')
| -rw-r--r-- | docs/WritingAnLLVMBackend.rst | 28 |
1 files changed, 13 insertions, 15 deletions
diff --git a/docs/WritingAnLLVMBackend.rst b/docs/WritingAnLLVMBackend.rst index fdadbb04e94f..023f6ffc4602 100644 --- a/docs/WritingAnLLVMBackend.rst +++ b/docs/WritingAnLLVMBackend.rst @@ -135,14 +135,13 @@ First, you should create a subdirectory under ``lib/Target`` to hold all the files related to your target. If your target is called "Dummy", create the directory ``lib/Target/Dummy``. -In this new directory, create a ``Makefile``. It is easiest to copy a -``Makefile`` of another target and modify it. It should at least contain the -``LEVEL``, ``LIBRARYNAME`` and ``TARGET`` variables, and then include -``$(LEVEL)/Makefile.common``. The library can be named ``LLVMDummy`` (for -example, see the MIPS target). Alternatively, you can split the library into -``LLVMDummyCodeGen`` and ``LLVMDummyAsmPrinter``, the latter of which should be -implemented in a subdirectory below ``lib/Target/Dummy`` (for example, see the -PowerPC target). +In this new directory, create a ``CMakeLists.txt``. It is easiest to copy a +``CMakeLists.txt`` of another target and modify it. It should at least contain +the ``LLVM_TARGET_DEFINITIONS`` variable. The library can be named ``LLVMDummy`` +(for example, see the MIPS target). Alternatively, you can split the library +into ``LLVMDummyCodeGen`` and ``LLVMDummyAsmPrinter``, the latter of which +should be implemented in a subdirectory below ``lib/Target/Dummy`` (for example, +see the PowerPC target). Note that these two naming schemes are hardcoded into ``llvm-config``. Using any other naming scheme will confuse ``llvm-config`` and produce a lot of @@ -156,13 +155,12 @@ generator, you should do what all current machine backends do: create a subclass of ``LLVMTargetMachine``. (To create a target from scratch, create a subclass of ``TargetMachine``.) -To get LLVM to actually build and link your target, you need to add it to the -``TARGETS_TO_BUILD`` variable. To do this, you modify the configure script to -know about your target when parsing the ``--enable-targets`` option. Search -the configure script for ``TARGETS_TO_BUILD``, add your target to the lists -there (some creativity required), and then reconfigure. Alternatively, you can -change ``autoconf/configure.ac`` and regenerate configure by running -``./autoconf/AutoRegen.sh``. +To get LLVM to actually build and link your target, you need to run ``cmake`` +with ``-DLLVM_EXPERIMENTAL_TARGETS_TO_BUILD=Dummy``. This will build your +target without needing to add it to the list of all the targets. + +Once your target is stable, you can add it to the ``LLVM_ALL_TARGETS`` variable +located in the main ``CMakeLists.txt``. Target Machine ============== |