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Diffstat (limited to 'docs/WritingAnLLVMBackend.html')
| -rw-r--r-- | docs/WritingAnLLVMBackend.html | 64 |
1 files changed, 52 insertions, 12 deletions
diff --git a/docs/WritingAnLLVMBackend.html b/docs/WritingAnLLVMBackend.html index 8016283..5a95185 100644 --- a/docs/WritingAnLLVMBackend.html +++ b/docs/WritingAnLLVMBackend.html @@ -22,6 +22,7 @@ <li><a href="#Preliminaries">Preliminaries</a></li> </ul> <li><a href="#TargetMachine">Target Machine</a></li> + <li><a href="#TargetRegistration">Target Registration</a></li> <li><a href="#RegisterSet">Register Set and Register Classes</a> <ul> <li><a href="#RegisterDef">Defining a Register</a></li> @@ -422,21 +423,62 @@ SparcTargetMachine::SparcTargetMachine(const Module &M, const std::string &a alignment, and then ABI preferred alignment.</li> </ul> +</div> + +<!-- *********************************************************************** --> +<div class="doc_section"> + <a name="TargetRegistration">Target Registration</a> +</div> +<!-- *********************************************************************** --> + +<div class="doc_text"> + +<p> +You must also register your target with the <tt>TargetRegistry</tt>, which is +what other LLVM tools use to be able to lookup and use your target at +runtime. The <tt>TargetRegistry</tt> can be used directly, but for most targets +there are helper templates which should take care of the work for you.</p> + +<p> +All targets should declare a global <tt>Target</tt> object which is used to +represent the target during registration. Then, in the target's TargetInfo +library, the target should define that object and use +the <tt>RegisterTarget</tt> template to register the target. For example, the Sparc registration code looks like this: +</p> + +<div class="doc_code"> +<pre> +Target llvm::TheSparcTarget; + +extern "C" void LLVMInitializeSparcTargetInfo() { + RegisterTarget<Triple::sparc, /*HasJIT=*/false> + X(TheSparcTarget, "sparc", "Sparc"); +} +</pre> +</div> + <p> -You must also register your target using the <tt>RegisterTarget</tt> -template. (See the <tt>TargetMachineRegistry</tt> class.) For example, -in <tt>SparcTargetMachine.cpp</tt>, the target is registered with: +This allows the <tt>TargetRegistry</tt> to look up the target by name or by +target triple. In addition, most targets will also register additional features +which are available in separate libraries. These registration steps are +separate, because some clients may wish to only link in some parts of the target +-- the JIT code generator does not require the use of the assembler printer, for +example. Here is an example of registering the Sparc assembly printer: </p> <div class="doc_code"> <pre> -namespace { - // Register the target. - RegisterTarget<SparcTargetMachine>X("sparc", "SPARC"); +extern "C" void LLVMInitializeSparcAsmPrinter() { + RegisterAsmPrinter<SparcAsmPrinter> X(TheSparcTarget); } </pre> </div> +<p> +For more information, see +"<a href="/doxygen/TargetRegistry_8h-source.html">llvm/Target/TargetRegistry.h</a>". +</p> + </div> <!-- *********************************************************************** --> @@ -2038,8 +2080,8 @@ SparcTargetAsmInfo::SparcTargetAsmInfo(const SparcTargetMachine &TM) { <p> The X86 assembly printer implementation (<tt>X86TargetAsmInfo</tt>) is an -example where the target specific <tt>TargetAsmInfo</tt> class uses overridden -methods: <tt>ExpandInlineAsm</tt> and <tt>PreferredEHDataFormat</tt>. +example where the target specific <tt>TargetAsmInfo</tt> class uses an +overridden methods: <tt>ExpandInlineAsm</tt>. </p> <p> @@ -2122,9 +2164,7 @@ in <tt>XXXGenAsmWriter.inc</tt> contains an implementation of the The implementations of <tt>printDeclare</tt>, <tt>printImplicitDef</tt>, <tt>printInlineAsm</tt>, and <tt>printLabel</tt> in <tt>AsmPrinter.cpp</tt> are generally adequate for printing assembly and do not need to be -overridden. (<tt>printBasicBlockLabel</tt> is another method that is implemented -in <tt>AsmPrinter.cpp</tt> that may be directly used in an implementation of -<tt>XXXAsmPrinter</tt>.) +overridden. </p> <p> @@ -2523,7 +2563,7 @@ with assembler. <a href="http://www.woo.com">Mason Woo</a> and <a href="http://misha.brukman.net">Misha Brukman</a><br> <a href="http://llvm.org">The LLVM Compiler Infrastructure</a> <br> - Last modified: $Date: 2009-04-05 02:44:06 +0200 (Sun, 05 Apr 2009) $ + Last modified: $Date: 2009-09-13 00:57:37 +0200 (Sun, 13 Sep 2009) $ </address> </body> |
