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diff --git a/docs/ExceptionHandling.html b/docs/ExceptionHandling.html index 009dbb5..16820f3 100644 --- a/docs/ExceptionHandling.html +++ b/docs/ExceptionHandling.html @@ -11,7 +11,7 @@ <body> -<div class="doc_title">Exception Handling in LLVM</div> +<h1>Exception Handling in LLVM</h1> <table class="layout" style="width:100%"> <tr class="layout"> @@ -58,10 +58,10 @@ <!-- *********************************************************************** --> -<div class="doc_section"><a name="introduction">Introduction</a></div> +<h2><a name="introduction">Introduction</a></h2> <!-- *********************************************************************** --> -<div class="doc_text"> +<div> <p>This document is the central repository for all information pertaining to exception handling in LLVM. It describes the format that LLVM exception @@ -70,14 +70,12 @@ provides specific examples of what exception handling information is used for in C/C++.</p> -</div> - <!-- ======================================================================= --> -<div class="doc_subsection"> +<h3> <a name="itanium">Itanium ABI Zero-cost Exception Handling</a> -</div> +</h3> -<div class="doc_text"> +<div> <p>Exception handling for most programming languages is designed to recover from conditions that rarely occur during general use of an application. To that @@ -106,11 +104,11 @@ </div> <!-- ======================================================================= --> -<div class="doc_subsection"> +<h3> <a name="sjlj">Setjmp/Longjmp Exception Handling</a> -</div> +</h3> -<div class="doc_text"> +<div> <p>Setjmp/Longjmp (SJLJ) based exception handling uses LLVM intrinsics <a href="#llvm_eh_sjlj_setjmp"><tt>llvm.eh.sjlj.setjmp</tt></a> and @@ -138,11 +136,11 @@ </div> <!-- ======================================================================= --> -<div class="doc_subsection"> +<h3> <a name="overview">Overview</a> -</div> +</h3> -<div class="doc_text"> +<div> <p>When an exception is thrown in LLVM code, the runtime does its best to find a handler suited to processing the circumstance.</p> @@ -185,12 +183,14 @@ </div> +</div> + <!-- ======================================================================= --> -<div class="doc_section"> +<h2> <a name="codegen">LLVM Code Generation</a> -</div> +</h2> -<div class="doc_text"> +<div> <p>At the time of this writing, only C++ exception handling support is available in LLVM. So the remainder of this document will be somewhat C++-centric.</p> @@ -200,14 +200,12 @@ we will describe the implementation of LLVM exception handling in terms of C++ examples.</p> -</div> - <!-- ======================================================================= --> -<div class="doc_subsection"> +<h3> <a name="throw">Throw</a> -</div> +</h3> -<div class="doc_text"> +<div> <p>Languages that support exception handling typically provide a <tt>throw</tt> operation to initiate the exception process. Internally, a throw operation @@ -225,11 +223,11 @@ </div> <!-- ======================================================================= --> -<div class="doc_subsection"> +<h3> <a name="try_catch">Try/Catch</a> -</div> +</h3> -<div class="doc_text"> +<div> <p>A call within the scope of a <i>try</i> statement can potentially raise an exception. In those circumstances, the LLVM C++ front-end replaces the call @@ -313,11 +311,11 @@ </div> <!-- ======================================================================= --> -<div class="doc_subsection"> +<h3> <a name="cleanups">Cleanups</a> -</div> +</h3> -<div class="doc_text"> +<div> <p>To handle destructors and cleanups in <tt>try</tt> code, control may not run directly from a landing pad to the first catch. Control may actually flow @@ -332,11 +330,11 @@ </div> <!-- ======================================================================= --> -<div class="doc_subsection"> +<h3> <a name="throw_filters">Throw Filters</a> -</div> +</h3> -<div class="doc_text"> +<div> <p>C++ allows the specification of which exception types can be thrown from a function. To represent this a top level landing pad may exist to filter out @@ -359,11 +357,11 @@ </div> <!-- ======================================================================= --> -<div class="doc_subsection"> +<h3> <a name="restrictions">Restrictions</a> -</div> +</h3> -<div class="doc_text"> +<div> <p>The semantics of the invoke instruction require that any exception that unwinds through an invoke call should result in a branch to the invoke's @@ -384,25 +382,25 @@ </div> +</div> + <!-- ======================================================================= --> -<div class="doc_section"> +<h2> <a name="format_common_intrinsics">Exception Handling Intrinsics</a> -</div> +</h2> -<div class="doc_text"> +<div> <p>LLVM uses several intrinsic functions (name prefixed with "llvm.eh") to provide exception handling information at various points in generated code.</p> -</div> - <!-- ======================================================================= --> -<div class="doc_subsubsection"> +<h4> <a name="llvm_eh_exception">llvm.eh.exception</a> -</div> +</h4> -<div class="doc_text"> +<div> <pre> i8* %<a href="#llvm_eh_exception">llvm.eh.exception</a>() @@ -413,11 +411,11 @@ </div> <!-- ======================================================================= --> -<div class="doc_subsubsection"> +<h4> <a name="llvm_eh_selector">llvm.eh.selector</a> -</div> +</h4> -<div class="doc_text"> +<div> <pre> i32 %<a href="#llvm_eh_selector">llvm.eh.selector</a>(i8*, i8*, ...) @@ -445,11 +443,11 @@ </div> <!-- ======================================================================= --> -<div class="doc_subsubsection"> +<h4> <a name="llvm_eh_typeid_for">llvm.eh.typeid.for</a> -</div> +</h4> -<div class="doc_text"> +<div> <pre> i32 %<a href="#llvm_eh_typeid_for">llvm.eh.typeid.for</a>(i8*) @@ -463,11 +461,11 @@ </div> <!-- ======================================================================= --> -<div class="doc_subsubsection"> +<h4> <a name="llvm_eh_sjlj_setjmp">llvm.eh.sjlj.setjmp</a> -</div> +</h4> -<div class="doc_text"> +<div> <pre> i32 %<a href="#llvm_eh_sjlj_setjmp">llvm.eh.sjlj.setjmp</a>(i8*) @@ -492,11 +490,11 @@ </div> <!-- ======================================================================= --> -<div class="doc_subsubsection"> +<h4> <a name="llvm_eh_sjlj_longjmp">llvm.eh.sjlj.longjmp</a> -</div> +</h4> -<div class="doc_text"> +<div> <pre> void %<a href="#llvm_eh_sjlj_longjmp">llvm.eh.sjlj.setjmp</a>(i8*) @@ -507,16 +505,16 @@ style exception handling. The single parameter is a pointer to a buffer populated by <a href="#llvm_eh_sjlj_setjmp"> <tt>llvm.eh.sjlj.setjmp</tt></a>. The frame pointer and stack pointer - are restored from the buffer, then control is transfered to the + are restored from the buffer, then control is transferred to the destination address.</p> </div> <!-- ======================================================================= --> -<div class="doc_subsubsection"> +<h4> <a name="llvm_eh_sjlj_lsda">llvm.eh.sjlj.lsda</a> -</div> +</h4> -<div class="doc_text"> +<div> <pre> i8* %<a href="#llvm_eh_sjlj_lsda">llvm.eh.sjlj.lsda</a>() @@ -531,11 +529,11 @@ </div> <!-- ======================================================================= --> -<div class="doc_subsubsection"> +<h4> <a name="llvm_eh_sjlj_callsite">llvm.eh.sjlj.callsite</a> -</div> +</h4> -<div class="doc_text"> +<div> <pre> void %<a href="#llvm_eh_sjlj_callsite">llvm.eh.sjlj.callsite</a>(i32) @@ -549,11 +547,11 @@ </div> <!-- ======================================================================= --> -<div class="doc_subsubsection"> +<h4> <a name="llvm_eh_sjlj_dispatchsetup">llvm.eh.sjlj.dispatchsetup</a> -</div> +</h4> -<div class="doc_text"> +<div> <pre> void %<a href="#llvm_eh_sjlj_dispatchsetup">llvm.eh.sjlj.dispatchsetup</a>(i32) @@ -565,24 +563,24 @@ </div> +</div> + <!-- ======================================================================= --> -<div class="doc_section"> +<h2> <a name="asm">Asm Table Formats</a> -</div> +</h2> -<div class="doc_text"> +<div> <p>There are two tables that are used by the exception handling runtime to determine which actions should take place when an exception is thrown.</p> -</div> - <!-- ======================================================================= --> -<div class="doc_subsection"> +<h3> <a name="unwind_tables">Exception Handling Frame</a> -</div> +</h3> -<div class="doc_text"> +<div> <p>An exception handling frame <tt>eh_frame</tt> is very similar to the unwind frame used by dwarf debug info. The frame contains all the information @@ -596,11 +594,11 @@ </div> <!-- ======================================================================= --> -<div class="doc_subsection"> +<h3> <a name="exception_tables">Exception Tables</a> -</div> +</h3> -<div class="doc_text"> +<div> <p>An exception table contains information about what actions to take when an exception is thrown in a particular part of a function's code. There is one @@ -611,12 +609,14 @@ </div> +</div> + <!-- ======================================================================= --> -<div class="doc_section"> +<h2> <a name="todo">ToDo</a> -</div> +</h2> -<div class="doc_text"> +<div> <ol> @@ -636,8 +636,8 @@ src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a> <a href="mailto:sabre@nondot.org">Chris Lattner</a><br> - <a href="http://llvm.org">LLVM Compiler Infrastructure</a><br> - Last modified: $Date: 2010-12-10 00:05:48 +0100 (Fri, 10 Dec 2010) $ + <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br> + Last modified: $Date: 2011-04-23 02:30:22 +0200 (Sat, 23 Apr 2011) $ </address> </body> |
