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diff --git a/docs/CompilerDriver.html b/docs/CompilerDriver.html deleted file mode 100644 index 1b2f808..0000000 --- a/docs/CompilerDriver.html +++ /dev/null @@ -1,687 +0,0 @@ -<?xml version="1.0" encoding="utf-8" ?> -<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> -<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> -<head> -<meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> -<meta name="generator" content="Docutils 0.6: http://docutils.sourceforge.net/" /> -<title>Customizing LLVMC: Reference Manual</title> -<link rel="stylesheet" href="llvm.css" type="text/css" /> -</head> -<body> -<div class="document" id="customizing-llvmc-reference-manual"> -<h1 class="title">Customizing LLVMC: Reference Manual</h1> - -<!-- This file was automatically generated by rst2html. -Please do not edit directly! -The ReST source lives in the directory 'tools/llvmc/doc'. --> -<div class="contents topic" id="contents"> -<p class="topic-title first">Contents</p> -<ul class="simple"> -<li><a class="reference internal" href="#introduction" id="id7">Introduction</a></li> -<li><a class="reference internal" href="#compiling-with-llvmc" id="id8">Compiling with <tt class="docutils literal">llvmc</tt></a></li> -<li><a class="reference internal" href="#predefined-options" id="id9">Predefined options</a></li> -<li><a class="reference internal" href="#compiling-llvmc-based-drivers" id="id10">Compiling LLVMC-based drivers</a></li> -<li><a class="reference internal" href="#customizing-llvmc-the-compilation-graph" id="id11">Customizing LLVMC: the compilation graph</a></li> -<li><a class="reference internal" href="#describing-options" id="id12">Describing options</a></li> -<li><a class="reference internal" href="#conditional-evaluation" id="id13">Conditional evaluation</a></li> -<li><a class="reference internal" href="#writing-a-tool-description" id="id14">Writing a tool description</a><ul> -<li><a class="reference internal" href="#id4" id="id15">Actions</a></li> -</ul> -</li> -<li><a class="reference internal" href="#language-map" id="id16">Language map</a></li> -<li><a class="reference internal" href="#option-preprocessor" id="id17">Option preprocessor</a></li> -<li><a class="reference internal" href="#more-advanced-topics" id="id18">More advanced topics</a><ul> -<li><a class="reference internal" href="#hooks-and-environment-variables" id="id19">Hooks and environment variables</a></li> -<li><a class="reference internal" href="#debugging" id="id20">Debugging</a></li> -<li><a class="reference internal" href="#conditioning-on-the-executable-name" id="id21">Conditioning on the executable name</a></li> -</ul> -</li> -</ul> -</div> -<div class="doc_author"> -<p>Written by <a href="mailto:foldr@codedgers.com">Mikhail Glushenkov</a></p> -</div><div class="section" id="introduction"> -<h1><a class="toc-backref" href="#id7">Introduction</a></h1> -<p>LLVMC is a generic compiler driver, designed to be customizable and -extensible. It plays the same role for LLVM as the <tt class="docutils literal">gcc</tt> program does for -GCC - LLVMC's job is essentially to transform a set of input files into a set of -targets depending on configuration rules and user options. What makes LLVMC -different is that these transformation rules are completely customizable - in -fact, LLVMC knows nothing about the specifics of transformation (even the -command-line options are mostly not hard-coded) and regards the transformation -structure as an abstract graph. The structure of this graph is described in -high-level TableGen code, from which an efficient C++ representation is -automatically derived. This makes it possible to adapt LLVMC for other -purposes - for example, as a build tool for game resources.</p> -<p>Because LLVMC employs <a class="reference external" href="http://llvm.org/docs/TableGenFundamentals.html">TableGen</a> as its configuration language, you -need to be familiar with it to customize LLVMC.</p> -</div> -<div class="section" id="compiling-with-llvmc"> -<h1><a class="toc-backref" href="#id8">Compiling with <tt class="docutils literal">llvmc</tt></a></h1> -<p>LLVMC tries hard to be as compatible with <tt class="docutils literal">gcc</tt> as possible, -although there are some small differences. Most of the time, however, -you shouldn't be able to notice them:</p> -<pre class="literal-block"> -$ # This works as expected: -$ llvmc -O3 -Wall hello.cpp -$ ./a.out -hello -</pre> -<p>One nice feature of LLVMC is that one doesn't have to distinguish between -different compilers for different languages (think <tt class="docutils literal">g++</tt> vs. <tt class="docutils literal">gcc</tt>) - the -right toolchain is chosen automatically based on input language names (which -are, in turn, determined from file extensions). If you want to force files -ending with ".c" to compile as C++, use the <tt class="docutils literal"><span class="pre">-x</span></tt> option, just like you would -do it with <tt class="docutils literal">gcc</tt>:</p> -<pre class="literal-block"> -$ # hello.c is really a C++ file -$ llvmc -x c++ hello.c -$ ./a.out -hello -</pre> -<p>On the other hand, when using LLVMC as a linker to combine several C++ -object files you should provide the <tt class="docutils literal"><span class="pre">--linker</span></tt> option since it's -impossible for LLVMC to choose the right linker in that case:</p> -<pre class="literal-block"> -$ llvmc -c hello.cpp -$ llvmc hello.o -[A lot of link-time errors skipped] -$ llvmc --linker=c++ hello.o -$ ./a.out -hello -</pre> -<p>By default, LLVMC uses <tt class="docutils literal"><span class="pre">llvm-gcc</span></tt> to compile the source code. It is also -possible to choose the <tt class="docutils literal">clang</tt> compiler with the <tt class="docutils literal"><span class="pre">-clang</span></tt> option.</p> -</div> -<div class="section" id="predefined-options"> -<h1><a class="toc-backref" href="#id9">Predefined options</a></h1> -<p>LLVMC has some built-in options that can't be overridden in the TableGen code:</p> -<ul class="simple"> -<li><tt class="docutils literal"><span class="pre">-o</span> FILE</tt> - Output file name.</li> -<li><tt class="docutils literal"><span class="pre">-x</span> LANGUAGE</tt> - Specify the language of the following input files -until the next -x option.</li> -<li><tt class="docutils literal"><span class="pre">-v</span></tt> - Enable verbose mode, i.e. print out all executed commands.</li> -<li><tt class="docutils literal"><span class="pre">--save-temps</span></tt> - Write temporary files to the current directory and do not -delete them on exit. This option can also take an argument: the -<tt class="docutils literal"><span class="pre">--save-temps=obj</span></tt> switch will write files into the directory specified with -the <tt class="docutils literal"><span class="pre">-o</span></tt> option. The <tt class="docutils literal"><span class="pre">--save-temps=cwd</span></tt> and <tt class="docutils literal"><span class="pre">--save-temps</span></tt> switches are -both synonyms for the default behaviour.</li> -<li><tt class="docutils literal"><span class="pre">--temp-dir</span> DIRECTORY</tt> - Store temporary files in the given directory. This -directory is deleted on exit unless <tt class="docutils literal"><span class="pre">--save-temps</span></tt> is specified. If -<tt class="docutils literal"><span class="pre">--save-temps=obj</span></tt> is also specified, <tt class="docutils literal"><span class="pre">--temp-dir</span></tt> is given the -precedence.</li> -<li><tt class="docutils literal"><span class="pre">--check-graph</span></tt> - Check the compilation for common errors like mismatched -output/input language names, multiple default edges and cycles. Exit with code -zero if no errors were found, and return the number of found errors -otherwise. Hidden option, useful for debugging.</li> -<li><tt class="docutils literal"><span class="pre">--view-graph</span></tt> - Show a graphical representation of the compilation graph -and exit. Requires that you have <tt class="docutils literal">dot</tt> and <tt class="docutils literal">gv</tt> programs installed. Hidden -option, useful for debugging.</li> -<li><tt class="docutils literal"><span class="pre">--write-graph</span></tt> - Write a <tt class="docutils literal"><span class="pre">compilation-graph.dot</span></tt> file in the current -directory with the compilation graph description in Graphviz format (identical -to the file used by the <tt class="docutils literal"><span class="pre">--view-graph</span></tt> option). The <tt class="docutils literal"><span class="pre">-o</span></tt> option can be -used to set the output file name. Hidden option, useful for debugging.</li> -<li><tt class="docutils literal"><span class="pre">--help</span></tt>, <tt class="docutils literal"><span class="pre">--help-hidden</span></tt>, <tt class="docutils literal"><span class="pre">--version</span></tt> - These options have -their standard meaning.</li> -</ul> -</div> -<div class="section" id="compiling-llvmc-based-drivers"> -<h1><a class="toc-backref" href="#id10">Compiling LLVMC-based drivers</a></h1> -<p>It's easiest to start working on your own LLVMC driver by copying the skeleton -project which lives under <tt class="docutils literal">$LLVMC_DIR/examples/Skeleton</tt>:</p> -<pre class="literal-block"> -$ cd $LLVMC_DIR/examples -$ cp -r Skeleton MyDriver -$ cd MyDriver -$ ls -AutoGenerated.td Hooks.cpp Main.cpp Makefile -</pre> -<p>As you can see, our basic driver consists of only three files (not counting the -build script). <tt class="docutils literal">AutoGenerated.td</tt> contains TableGen description of the -compilation graph; its format is documented in the following -sections. <tt class="docutils literal">Hooks.cpp</tt> is an empty file that should be used for hook -definitions (see <a class="reference internal" href="#hooks">below</a>). <tt class="docutils literal">Main.cpp</tt> is just a helper used to compile the -auto-generated C++ code produced from TableGen source.</p> -<p>The first thing that you should do is to change the <tt class="docutils literal">LLVMC_BASED_DRIVER</tt> -variable in the <tt class="docutils literal">Makefile</tt>:</p> -<pre class="literal-block"> -LLVMC_BASED_DRIVER=MyDriver -</pre> -<p>It can also be a good idea to put your TableGen code into a file with a less -generic name:</p> -<pre class="literal-block"> -$ touch MyDriver.td -$ vim AutoGenerated.td -[...] -include "MyDriver.td" -</pre> -<p>If you have more than one TableGen source file, they all should be included from -<tt class="docutils literal">AutoGenerated.td</tt>, since this file is used by the build system to generate -C++ code.</p> -<p>To build your driver, just <tt class="docutils literal">cd</tt> to its source directory and run <tt class="docutils literal">make</tt>. The -resulting executable will be put into <tt class="docutils literal"><span class="pre">$LLVM_OBJ_DIR/$(BuildMode)/bin</span></tt>.</p> -<p>If you're compiling LLVM with different source and object directories, then you -must perform the following additional steps before running <tt class="docutils literal">make</tt>:</p> -<pre class="literal-block"> -# LLVMC_SRC_DIR = $LLVM_SRC_DIR/tools/llvmc/ -# LLVMC_OBJ_DIR = $LLVM_OBJ_DIR/tools/llvmc/ -$ mkdir $LLVMC_OBJ_DIR/examples/MyDriver/ -$ cp $LLVMC_SRC_DIR/examples/MyDriver/Makefile \ - $LLVMC_OBJ_DIR/examples/MyDriver/ -$ cd $LLVMC_OBJ_DIR/examples/MyDriver -$ make -</pre> -</div> -<div class="section" id="customizing-llvmc-the-compilation-graph"> -<h1><a class="toc-backref" href="#id11">Customizing LLVMC: the compilation graph</a></h1> -<p>Each TableGen configuration file should include the common definitions:</p> -<pre class="literal-block"> -include "llvm/CompilerDriver/Common.td" -</pre> -<p>Internally, LLVMC stores information about possible source transformations in -form of a graph. Nodes in this graph represent tools, and edges between two -nodes represent a transformation path. A special "root" node is used to mark -entry points for the transformations. LLVMC also assigns a weight to each edge -(more on this later) to choose between several alternative edges.</p> -<p>The definition of the compilation graph (see file <tt class="docutils literal">llvmc/src/Base.td</tt> for an -example) is just a list of edges:</p> -<pre class="literal-block"> -def CompilationGraph : CompilationGraph<[ - Edge<"root", "llvm_gcc_c">, - Edge<"root", "llvm_gcc_assembler">, - ... - - Edge<"llvm_gcc_c", "llc">, - Edge<"llvm_gcc_cpp", "llc">, - ... - - OptionalEdge<"llvm_gcc_c", "opt", (case (switch_on "opt"), - (inc_weight))>, - OptionalEdge<"llvm_gcc_cpp", "opt", (case (switch_on "opt"), - (inc_weight))>, - ... - - OptionalEdge<"llvm_gcc_assembler", "llvm_gcc_cpp_linker", - (case (input_languages_contain "c++"), (inc_weight), - (or (parameter_equals "linker", "g++"), - (parameter_equals "linker", "c++")), (inc_weight))>, - ... - - ]>; -</pre> -<p>As you can see, the edges can be either default or optional, where optional -edges are differentiated by an additional <tt class="docutils literal">case</tt> expression used to calculate -the weight of this edge. Notice also that we refer to tools via their names (as -strings). This makes it possible to add edges to an existing compilation graph -without having to know about all tool definitions used in the graph.</p> -<p>The default edges are assigned a weight of 1, and optional edges get a weight of -0 + 2*N where N is the number of tests that evaluated to true in the <tt class="docutils literal">case</tt> -expression. It is also possible to provide an integer parameter to -<tt class="docutils literal">inc_weight</tt> and <tt class="docutils literal">dec_weight</tt> - in this case, the weight is increased (or -decreased) by the provided value instead of the default 2. Default weight of an -optional edge can be changed by using the <tt class="docutils literal">default</tt> clause of the <tt class="docutils literal">case</tt> -construct.</p> -<p>When passing an input file through the graph, LLVMC picks the edge with the -maximum weight. To avoid ambiguity, there should be only one default edge -between two nodes (with the exception of the root node, which gets a special -treatment - there you are allowed to specify one default edge <em>per language</em>).</p> -<p>When multiple compilation graphs are defined, they are merged together. Multiple -edges with the same end nodes are not allowed (i.e. the graph is not a -multigraph), and will lead to a compile-time error.</p> -<p>To get a visual representation of the compilation graph (useful for debugging), -run <tt class="docutils literal">llvmc <span class="pre">--view-graph</span></tt>. You will need <tt class="docutils literal">dot</tt> and <tt class="docutils literal">gsview</tt> installed for -this to work properly.</p> -</div> -<div class="section" id="describing-options"> -<h1><a class="toc-backref" href="#id12">Describing options</a></h1> -<p>Command-line options supported by the driver are defined by using an -<tt class="docutils literal">OptionList</tt>:</p> -<pre class="literal-block"> -def Options : OptionList<[ -(switch_option "E", (help "Help string")), -(alias_option "quiet", "q") -... -]>; -</pre> -<p>As you can see, the option list is just a list of DAGs, where each DAG is an -option description consisting of the option name and some properties. More than -one option list can be defined (they are all merged together in the end), which -can be handy if one wants to separate option groups syntactically.</p> -<ul> -<li><p class="first">Possible option types:</p> -<blockquote> -<ul class="simple"> -<li><tt class="docutils literal">switch_option</tt> - a simple boolean switch without arguments, for example -<tt class="docutils literal"><span class="pre">-O2</span></tt> or <tt class="docutils literal"><span class="pre">-time</span></tt>. At most one occurrence is allowed by default.</li> -<li><tt class="docutils literal">parameter_option</tt> - option that takes one argument, for example -<tt class="docutils literal"><span class="pre">-std=c99</span></tt>. It is also allowed to use spaces instead of the equality -sign: <tt class="docutils literal"><span class="pre">-std</span> c99</tt>. At most one occurrence is allowed.</li> -<li><tt class="docutils literal">parameter_list_option</tt> - same as the above, but more than one option -occurrence is allowed.</li> -<li><tt class="docutils literal">prefix_option</tt> - same as the parameter_option, but the option name and -argument do not have to be separated. Example: <tt class="docutils literal"><span class="pre">-ofile</span></tt>. This can be also -specified as <tt class="docutils literal"><span class="pre">-o</span> file</tt>; however, <tt class="docutils literal"><span class="pre">-o=file</span></tt> will be parsed incorrectly -(<tt class="docutils literal">=file</tt> will be interpreted as option value). At most one occurrence is -allowed.</li> -<li><tt class="docutils literal">prefix_list_option</tt> - same as the above, but more than one occurrence of -the option is allowed; example: <tt class="docutils literal"><span class="pre">-lm</span> <span class="pre">-lpthread</span></tt>.</li> -<li><tt class="docutils literal">alias_option</tt> - a special option type for creating aliases. Unlike other -option types, aliases are not allowed to have any properties besides the -aliased option name. -Usage example: <tt class="docutils literal">(alias_option "preprocess", "E")</tt></li> -<li><tt class="docutils literal">switch_list_option</tt> - like <tt class="docutils literal">switch_option</tt> with the <tt class="docutils literal">zero_or_more</tt> -property, but remembers how many times the switch was turned on. Useful -mostly for forwarding. Example: when <tt class="docutils literal"><span class="pre">-foo</span></tt> is a switch option (with the -<tt class="docutils literal">zero_or_more</tt> property), the command <tt class="docutils literal">driver <span class="pre">-foo</span> <span class="pre">-foo</span></tt> is forwarded -as <tt class="docutils literal"><span class="pre">some-tool</span> <span class="pre">-foo</span></tt>, but when <tt class="docutils literal"><span class="pre">-foo</span></tt> is a switch list, the same command -is forwarded as <tt class="docutils literal"><span class="pre">some-tool</span> <span class="pre">-foo</span> <span class="pre">-foo</span></tt>.</li> -</ul> -</blockquote> -</li> -<li><p class="first">Possible option properties:</p> -<blockquote> -<ul class="simple"> -<li><tt class="docutils literal">help</tt> - help string associated with this option. Used for <tt class="docutils literal"><span class="pre">--help</span></tt> -output.</li> -<li><tt class="docutils literal">required</tt> - this option must be specified exactly once (or, in case of -the list options without the <tt class="docutils literal">multi_val</tt> property, at least -once). Incompatible with <tt class="docutils literal">optional</tt> and <tt class="docutils literal">one_or_more</tt>.</li> -<li><tt class="docutils literal">optional</tt> - the option can be specified either zero times or exactly -once. The default for switch options. Useful only for list options in -conjunction with <tt class="docutils literal">multi_val</tt>. Incompatible with <tt class="docutils literal">required</tt>, -<tt class="docutils literal">zero_or_more</tt> and <tt class="docutils literal">one_or_more</tt>.</li> -<li><tt class="docutils literal">one_or_more</tt> - the option must be specified at least once. Can be useful -to allow switch options be both obligatory and be specified multiple -times. For list options is useful only in conjunction with <tt class="docutils literal">multi_val</tt>; -for ordinary it is synonymous with <tt class="docutils literal">required</tt>. Incompatible with -<tt class="docutils literal">required</tt>, <tt class="docutils literal">optional</tt> and <tt class="docutils literal">zero_or_more</tt>.</li> -<li><tt class="docutils literal">zero_or_more</tt> - the option can be specified zero or more times. Useful -to allow a single switch option to be specified more than -once. Incompatible with <tt class="docutils literal">required</tt>, <tt class="docutils literal">optional</tt> and <tt class="docutils literal">one_or_more</tt>.</li> -<li><tt class="docutils literal">hidden</tt> - the description of this option will not appear in -the <tt class="docutils literal"><span class="pre">--help</span></tt> output (but will appear in the <tt class="docutils literal"><span class="pre">--help-hidden</span></tt> -output).</li> -<li><tt class="docutils literal">really_hidden</tt> - the option will not be mentioned in any help -output.</li> -<li><tt class="docutils literal">comma_separated</tt> - Indicates that any commas specified for an option's -value should be used to split the value up into multiple values for the -option. This property is valid only for list options. In conjunction with -<tt class="docutils literal">forward_value</tt> can be used to implement option forwarding in style of -gcc's <tt class="docutils literal"><span class="pre">-Wa,</span></tt>.</li> -<li><tt class="docutils literal">multi_val n</tt> - this option takes <em>n</em> arguments (can be useful in some -special cases). Usage example: <tt class="docutils literal">(parameter_list_option "foo", (multi_val -3))</tt>; the command-line syntax is '-foo a b c'. Only list options can have -this attribute; you can, however, use the <tt class="docutils literal">one_or_more</tt>, <tt class="docutils literal">optional</tt> -and <tt class="docutils literal">required</tt> properties.</li> -<li><tt class="docutils literal">init</tt> - this option has a default value, either a string (if it is a -parameter), or a boolean (if it is a switch; as in C++, boolean constants -are called <tt class="docutils literal">true</tt> and <tt class="docutils literal">false</tt>). List options can't have <tt class="docutils literal">init</tt> -attribute. -Usage examples: <tt class="docutils literal">(switch_option "foo", (init true))</tt>; <tt class="docutils literal">(prefix_option -"bar", (init <span class="pre">"baz"))</span></tt>.</li> -</ul> -</blockquote> -</li> -</ul> -</div> -<div class="section" id="conditional-evaluation"> -<span id="case"></span><h1><a class="toc-backref" href="#id13">Conditional evaluation</a></h1> -<p>The 'case' construct is the main means by which programmability is achieved in -LLVMC. It can be used to calculate edge weights, program actions and modify the -shell commands to be executed. The 'case' expression is designed after the -similarly-named construct in functional languages and takes the form <tt class="docutils literal">(case -(test_1), statement_1, (test_2), statement_2, ... (test_N), statement_N)</tt>. The -statements are evaluated only if the corresponding tests evaluate to true.</p> -<p>Examples:</p> -<pre class="literal-block"> -// Edge weight calculation - -// Increases edge weight by 5 if "-A" is provided on the -// command-line, and by 5 more if "-B" is also provided. -(case - (switch_on "A"), (inc_weight 5), - (switch_on "B"), (inc_weight 5)) - - -// Tool command line specification - -// Evaluates to "cmdline1" if the option "-A" is provided on the -// command line; to "cmdline2" if "-B" is provided; -// otherwise to "cmdline3". - -(case - (switch_on "A"), "cmdline1", - (switch_on "B"), "cmdline2", - (default), "cmdline3") -</pre> -<p>Note the slight difference in 'case' expression handling in contexts of edge -weights and command line specification - in the second example the value of the -<tt class="docutils literal">"B"</tt> switch is never checked when switch <tt class="docutils literal">"A"</tt> is enabled, and the whole -expression always evaluates to <tt class="docutils literal">"cmdline1"</tt> in that case.</p> -<p>Case expressions can also be nested, i.e. the following is legal:</p> -<pre class="literal-block"> -(case (switch_on "E"), (case (switch_on "o"), ..., (default), ...) - (default), ...) -</pre> -<p>You should, however, try to avoid doing that because it hurts readability. It is -usually better to split tool descriptions and/or use TableGen inheritance -instead.</p> -<ul class="simple"> -<li>Possible tests are:<ul> -<li><tt class="docutils literal">switch_on</tt> - Returns true if a given command-line switch is provided by -the user. Can be given multiple arguments, in that case <tt class="docutils literal">(switch_on "foo", -"bar", "baz")</tt> is equivalent to <tt class="docutils literal">(and (switch_on <span class="pre">"foo"),</span> (switch_on -<span class="pre">"bar"),</span> (switch_on <span class="pre">"baz"))</span></tt>. -Example: <tt class="docutils literal">(switch_on "opt")</tt>.</li> -<li><tt class="docutils literal">any_switch_on</tt> - Given a number of switch options, returns true if any of -the switches is turned on. -Example: <tt class="docutils literal">(any_switch_on "foo", "bar", "baz")</tt> is equivalent to <tt class="docutils literal">(or -(switch_on <span class="pre">"foo"),</span> (switch_on <span class="pre">"bar"),</span> (switch_on <span class="pre">"baz"))</span></tt>.</li> -<li><tt class="docutils literal">parameter_equals</tt> - Returns true if a command-line parameter (first -argument) equals a given value (second argument). -Example: <tt class="docutils literal">(parameter_equals "W", "all")</tt>.</li> -<li><tt class="docutils literal">element_in_list</tt> - Returns true if a command-line parameter list (first -argument) contains a given value (second argument). -Example: <tt class="docutils literal">(element_in_list "l", "pthread")</tt>.</li> -<li><tt class="docutils literal">input_languages_contain</tt> - Returns true if a given language -belongs to the current input language set. -Example: <tt class="docutils literal">(input_languages_contain <span class="pre">"c++")</span></tt>.</li> -<li><tt class="docutils literal">in_language</tt> - Evaluates to true if the input file language is equal to -the argument. At the moment works only with <tt class="docutils literal">command</tt> and <tt class="docutils literal">actions</tt> (on -non-join nodes). -Example: <tt class="docutils literal">(in_language <span class="pre">"c++")</span></tt>.</li> -<li><tt class="docutils literal">not_empty</tt> - Returns true if a given option (which should be either a -parameter or a parameter list) is set by the user. Like <tt class="docutils literal">switch_on</tt>, can -be also given multiple arguments. -Examples: <tt class="docutils literal">(not_empty "o")</tt>, <tt class="docutils literal">(not_empty "o", "l")</tt>.</li> -<li><tt class="docutils literal">any_not_empty</tt> - Returns true if <tt class="docutils literal">not_empty</tt> returns true for any of -the provided options. -Example: <tt class="docutils literal">(any_not_empty "foo", "bar", "baz")</tt> is equivalent to <tt class="docutils literal">(or -(not_empty <span class="pre">"foo"),</span> (not_empty <span class="pre">"bar"),</span> (not_empty <span class="pre">"baz"))</span></tt>.</li> -<li><tt class="docutils literal">empty</tt> - The opposite of <tt class="docutils literal">not_empty</tt>. Equivalent to <tt class="docutils literal">(not (not_empty -X))</tt>. Can be given multiple arguments.</li> -<li><tt class="docutils literal">any_not_empty</tt> - Returns true if <tt class="docutils literal">not_empty</tt> returns true for any of -the provided options. -Example: <tt class="docutils literal">(any_empty "foo", "bar", "baz")</tt> is equivalent to <tt class="docutils literal">(or -(not_empty <span class="pre">"foo"),</span> (not_empty <span class="pre">"bar"),</span> (not_empty <span class="pre">"baz"))</span></tt>.</li> -<li><tt class="docutils literal">single_input_file</tt> - Returns true if there was only one input file -provided on the command-line. Used without arguments: -<tt class="docutils literal">(single_input_file)</tt>.</li> -<li><tt class="docutils literal">multiple_input_files</tt> - Equivalent to <tt class="docutils literal">(not (single_input_file))</tt> (the -case of zero input files is considered an error).</li> -<li><tt class="docutils literal">default</tt> - Always evaluates to true. Should always be the last -test in the <tt class="docutils literal">case</tt> expression.</li> -<li><tt class="docutils literal">and</tt> - A standard logical combinator that returns true iff all of -its arguments return true. Used like this: <tt class="docutils literal">(and (test1), (test2), -... (testN))</tt>. Nesting of <tt class="docutils literal">and</tt> and <tt class="docutils literal">or</tt> is allowed, but not -encouraged.</li> -<li><tt class="docutils literal">or</tt> - A logical combinator that returns true iff any of its arguments -return true. -Example: <tt class="docutils literal">(or (test1), (test2), ... (testN))</tt>.</li> -<li><tt class="docutils literal">not</tt> - Standard unary logical combinator that negates its -argument. -Example: <tt class="docutils literal">(not (or (test1), (test2), ... <span class="pre">(testN)))</span></tt>.</li> -</ul> -</li> -</ul> -</div> -<div class="section" id="writing-a-tool-description"> -<h1><a class="toc-backref" href="#id14">Writing a tool description</a></h1> -<p>As was said earlier, nodes in the compilation graph represent tools, which are -described separately. A tool definition looks like this (taken from the -<tt class="docutils literal">llvmc/src/Base.td</tt> file):</p> -<pre class="literal-block"> -def llvm_gcc_cpp : Tool<[ - (in_language "c++"), - (out_language "llvm-assembler"), - (output_suffix "bc"), - (command "llvm-g++ -c -emit-llvm"), - (sink) - ]>; -</pre> -<p>This defines a new tool called <tt class="docutils literal">llvm_gcc_cpp</tt>, which is an alias for -<tt class="docutils literal"><span class="pre">llvm-g++</span></tt>. As you can see, a tool definition is just a list of properties; -most of them should be self-explanatory. The <tt class="docutils literal">sink</tt> property means that this -tool should be passed all command-line options that aren't mentioned in the -option list.</p> -<p>The complete list of all currently implemented tool properties follows.</p> -<ul class="simple"> -<li>Possible tool properties:<ul> -<li><tt class="docutils literal">in_language</tt> - input language name. Can be given multiple arguments, in -case the tool supports multiple input languages. Used for typechecking and -mapping file extensions to tools.</li> -<li><tt class="docutils literal">out_language</tt> - output language name. Multiple output languages are -allowed. Used for typechecking the compilation graph.</li> -<li><tt class="docutils literal">output_suffix</tt> - output file suffix. Can also be changed dynamically, see -documentation on <a class="reference internal" href="#actions">actions</a>.</li> -</ul> -</li> -</ul> -<blockquote> -<ul class="simple"> -<li><tt class="docutils literal">command</tt> - the actual command used to run the tool. You can use output -redirection with <tt class="docutils literal">></tt>, hook invocations (<tt class="docutils literal">$CALL</tt>), environment variables -(via <tt class="docutils literal">$ENV</tt>) and the <tt class="docutils literal">case</tt> construct.</li> -<li><tt class="docutils literal">join</tt> - this tool is a "join node" in the graph, i.e. it gets a list of -input files and joins them together. Used for linkers.</li> -<li><tt class="docutils literal">sink</tt> - all command-line options that are not handled by other tools are -passed to this tool.</li> -<li><tt class="docutils literal">actions</tt> - A single big <tt class="docutils literal">case</tt> expression that specifies how this tool -reacts on command-line options (described in more detail <a class="reference internal" href="#actions">below</a>).</li> -</ul> -</blockquote> -<blockquote> -<ul class="simple"> -<li><tt class="docutils literal">out_file_option</tt>, <tt class="docutils literal">in_file_option</tt> - Options appended to the -<tt class="docutils literal">command</tt> string to designate output and input files. Default values are -<tt class="docutils literal"><span class="pre">"-o"</span></tt> and <tt class="docutils literal">""</tt>, respectively.</li> -</ul> -</blockquote> -<div class="section" id="id4"> -<span id="actions"></span><h2><a class="toc-backref" href="#id15">Actions</a></h2> -<p>A tool often needs to react to command-line options, and this is precisely what -the <tt class="docutils literal">actions</tt> property is for. The next example illustrates this feature:</p> -<pre class="literal-block"> -def llvm_gcc_linker : Tool<[ - (in_language "object-code"), - (out_language "executable"), - (output_suffix "out"), - (command "llvm-gcc"), - (join), - (actions (case (not_empty "L"), (forward "L"), - (not_empty "l"), (forward "l"), - (not_empty "dummy"), - [(append_cmd "-dummy1"), (append_cmd "-dummy2")]) - ]>; -</pre> -<p>The <tt class="docutils literal">actions</tt> tool property is implemented on top of the omnipresent <tt class="docutils literal">case</tt> -expression. It associates one or more different <em>actions</em> with given -conditions - in the example, the actions are <tt class="docutils literal">forward</tt>, which forwards a given -option unchanged, and <tt class="docutils literal">append_cmd</tt>, which appends a given string to the tool -execution command. Multiple actions can be associated with a single condition by -using a list of actions (used in the example to append some dummy options). The -same <tt class="docutils literal">case</tt> construct can also be used in the <tt class="docutils literal">cmd_line</tt> property to modify -the tool command line.</p> -<p>The "join" property used in the example means that this tool behaves like a -linker.</p> -<p>The list of all possible actions follows.</p> -<ul> -<li><p class="first">Possible actions:</p> -<blockquote> -<ul class="simple"> -<li><tt class="docutils literal">append_cmd</tt> - Append a string to the tool invocation command. -Example: <tt class="docutils literal">(case (switch_on <span class="pre">"pthread"),</span> (append_cmd <span class="pre">"-lpthread"))</span></tt>.</li> -<li><tt class="docutils literal">error</tt> - Exit with error. -Example: <tt class="docutils literal">(error "Mixing <span class="pre">-c</span> and <span class="pre">-S</span> is not <span class="pre">allowed!")</span></tt>.</li> -<li><tt class="docutils literal">warning</tt> - Print a warning. -Example: <tt class="docutils literal">(warning "Specifying both <span class="pre">-O1</span> and <span class="pre">-O2</span> is <span class="pre">meaningless!")</span></tt>.</li> -<li><tt class="docutils literal">forward</tt> - Forward the option unchanged. -Example: <tt class="docutils literal">(forward "Wall")</tt>.</li> -<li><tt class="docutils literal">forward_as</tt> - Change the option's name, but forward the argument -unchanged. -Example: <tt class="docutils literal">(forward_as "O0", <span class="pre">"--disable-optimization")</span></tt>.</li> -<li><tt class="docutils literal">forward_value</tt> - Forward only option's value. Cannot be used with switch -options (since they don't have values), but works fine with lists. -Example: <tt class="docutils literal">(forward_value <span class="pre">"Wa,")</span></tt>.</li> -<li><tt class="docutils literal">forward_transformed_value</tt> - As above, but applies a hook to the -option's value before forwarding (see <a class="reference internal" href="#hooks">below</a>). When -<tt class="docutils literal">forward_transformed_value</tt> is applied to a list -option, the hook must have signature -<tt class="docutils literal"><span class="pre">std::string</span> <span class="pre">hooks::HookName</span> (const <span class="pre">std::vector<std::string>&)</span></tt>. -Example: <tt class="docutils literal">(forward_transformed_value "m", "ConvertToMAttr")</tt>.</li> -<li><tt class="docutils literal">output_suffix</tt> - Modify the output suffix of this tool. -Example: <tt class="docutils literal">(output_suffix "i")</tt>.</li> -<li><tt class="docutils literal">stop_compilation</tt> - Stop compilation after this tool processes its -input. Used without arguments. -Example: <tt class="docutils literal">(stop_compilation)</tt>.</li> -</ul> -</blockquote> -</li> -</ul> -</div> -</div> -<div class="section" id="language-map"> -<h1><a class="toc-backref" href="#id16">Language map</a></h1> -<p>If you are adding support for a new language to LLVMC, you'll need to modify the -language map, which defines mappings from file extensions to language names. It -is used to choose the proper toolchain(s) for a given input file set. Language -map definition looks like this:</p> -<pre class="literal-block"> -def LanguageMap : LanguageMap< - [LangToSuffixes<"c++", ["cc", "cp", "cxx", "cpp", "CPP", "c++", "C"]>, - LangToSuffixes<"c", ["c"]>, - ... - ]>; -</pre> -<p>For example, without those definitions the following command wouldn't work:</p> -<pre class="literal-block"> -$ llvmc hello.cpp -llvmc: Unknown suffix: cpp -</pre> -<p>The language map entries are needed only for the tools that are linked from the -root node. A tool can have multiple output languages.</p> -</div> -<div class="section" id="option-preprocessor"> -<h1><a class="toc-backref" href="#id17">Option preprocessor</a></h1> -<p>It is sometimes useful to run error-checking code before processing the -compilation graph. For example, if optimization options "-O1" and "-O2" are -implemented as switches, we might want to output a warning if the user invokes -the driver with both of these options enabled.</p> -<p>The <tt class="docutils literal">OptionPreprocessor</tt> feature is reserved specially for these -occasions. Example (adapted from <tt class="docutils literal">llvm/src/Base.td.in</tt>):</p> -<pre class="literal-block"> -def Preprocess : OptionPreprocessor< -(case (not (any_switch_on "O0", "O1", "O2", "O3")), - (set_option "O2"), - (and (switch_on "O3"), (any_switch_on "O0", "O1", "O2")), - (unset_option "O0", "O1", "O2"), - (and (switch_on "O2"), (any_switch_on "O0", "O1")), - (unset_option "O0", "O1"), - (and (switch_on "O1"), (switch_on "O0")), - (unset_option "O0")) ->; -</pre> -<p>Here, <tt class="docutils literal">OptionPreprocessor</tt> is used to unset all spurious <tt class="docutils literal"><span class="pre">-O</span></tt> options so -that they are not forwarded to the compiler. If no optimization options are -specified, <tt class="docutils literal"><span class="pre">-O2</span></tt> is enabled.</p> -<p><tt class="docutils literal">OptionPreprocessor</tt> is basically a single big <tt class="docutils literal">case</tt> expression, which is -evaluated only once right after the driver is started. The only allowed actions -in <tt class="docutils literal">OptionPreprocessor</tt> are <tt class="docutils literal">error</tt>, <tt class="docutils literal">warning</tt>, and two special actions: -<tt class="docutils literal">unset_option</tt> and <tt class="docutils literal">set_option</tt>. As their names suggest, they can be used to -set or unset a given option. To set an option with <tt class="docutils literal">set_option</tt>, use the -two-argument form: <tt class="docutils literal">(set_option "parameter", VALUE)</tt>. Here, <tt class="docutils literal">VALUE</tt> can be -either a string, a string list, or a boolean constant.</p> -<p>For convenience, <tt class="docutils literal">set_option</tt> and <tt class="docutils literal">unset_option</tt> also work with multiple -arguments. That is, instead of <tt class="docutils literal">[(unset_option <span class="pre">"A"),</span> (unset_option <span class="pre">"B")]</span></tt> you -can use <tt class="docutils literal">(unset_option "A", "B")</tt>. Obviously, <tt class="docutils literal">(set_option "A", "B")</tt> is -only valid if both <tt class="docutils literal">A</tt> and <tt class="docutils literal">B</tt> are switches.</p> -</div> -<div class="section" id="more-advanced-topics"> -<h1><a class="toc-backref" href="#id18">More advanced topics</a></h1> -<div class="section" id="hooks-and-environment-variables"> -<span id="hooks"></span><h2><a class="toc-backref" href="#id19">Hooks and environment variables</a></h2> -<p>Normally, LLVMC searches for programs in the system <tt class="docutils literal">PATH</tt>. Sometimes, this is -not sufficient: for example, we may want to specify tool paths or names in the -configuration file. This can be achieved via the hooks mechanism. To write your -own hooks, add their definitions to the <tt class="docutils literal">Hooks.cpp</tt> or drop a <tt class="docutils literal">.cpp</tt> file -into your driver directory. Hooks should live in the <tt class="docutils literal">hooks</tt> namespace and -have the signature <tt class="docutils literal"><span class="pre">std::string</span> <span class="pre">hooks::MyHookName</span> ([const char* Arg0 [ const -char* Arg2 [, <span class="pre">...]]])</span></tt>. They can be used from the <tt class="docutils literal">command</tt> tool property:</p> -<pre class="literal-block"> -(command "$CALL(MyHook)/path/to/file -o $CALL(AnotherHook)") -</pre> -<p>To pass arguments to hooks, use the following syntax:</p> -<pre class="literal-block"> -(command "$CALL(MyHook, 'Arg1', 'Arg2', 'Arg # 3')/path/to/file -o1 -o2") -</pre> -<p>It is also possible to use environment variables in the same manner:</p> -<pre class="literal-block"> -(command "$ENV(VAR1)/path/to/file -o $ENV(VAR2)") -</pre> -<p>To change the command line string based on user-provided options use -the <tt class="docutils literal">case</tt> expression (documented <a class="reference internal" href="#case">above</a>):</p> -<pre class="literal-block"> -(command - (case - (switch_on "E"), - "llvm-g++ -E -x c $INFILE -o $OUTFILE", - (default), - "llvm-g++ -c -x c $INFILE -o $OUTFILE -emit-llvm")) -</pre> -</div> -<div class="section" id="debugging"> -<h2><a class="toc-backref" href="#id20">Debugging</a></h2> -<p>When writing LLVMC-based drivers, it can be useful to get a visual view of the -resulting compilation graph. This can be achieved via the command line option -<tt class="docutils literal"><span class="pre">--view-graph</span></tt> (which assumes that <a class="reference external" href="http://www.graphviz.org/">Graphviz</a> and <a class="reference external" href="http://pages.cs.wisc.edu/~ghost/">Ghostview</a> are -installed). There is also a <tt class="docutils literal"><span class="pre">--write-graph</span></tt> option that creates a Graphviz -source file (<tt class="docutils literal"><span class="pre">compilation-graph.dot</span></tt>) in the current directory.</p> -<p>Another useful <tt class="docutils literal">llvmc</tt> option is <tt class="docutils literal"><span class="pre">--check-graph</span></tt>. It checks the compilation -graph for common errors like mismatched output/input language names, multiple -default edges and cycles. When invoked with <tt class="docutils literal"><span class="pre">--check-graph</span></tt>, <tt class="docutils literal">llvmc</tt> doesn't -perform any compilation tasks and returns the number of encountered errors as -its status code. In the future, these checks will be performed at compile-time -and this option will disappear.</p> -</div> -<div class="section" id="conditioning-on-the-executable-name"> -<h2><a class="toc-backref" href="#id21">Conditioning on the executable name</a></h2> -<p>For now, the executable name (the value passed to the driver in <tt class="docutils literal">argv[0]</tt>) is -accessible only in the C++ code (i.e. hooks). Use the following code:</p> -<pre class="literal-block"> -namespace llvmc { -extern const char* ProgramName; -} - -namespace hooks { - -std::string MyHook() { -//... -if (strcmp(ProgramName, "mydriver") == 0) { - //... - -} - -} // end namespace hooks -</pre> -<p>In general, you're encouraged not to make the behaviour dependent on the -executable file name, and use command-line switches instead. See for example how -the <tt class="docutils literal">llvmc</tt> program behaves when it needs to choose the correct linker options -(think <tt class="docutils literal">g++</tt> vs. <tt class="docutils literal">gcc</tt>).</p> -<hr /> -<address> -<a href="http://jigsaw.w3.org/css-validator/check/referer"> -<img src="http://jigsaw.w3.org/css-validator/images/vcss-blue" - alt="Valid CSS" /></a> -<a href="http://validator.w3.org/check?uri=referer"> -<img src="http://www.w3.org/Icons/valid-xhtml10-blue" - alt="Valid XHTML 1.0 Transitional"/></a> - -<a href="mailto:foldr@codedgers.com">Mikhail Glushenkov</a><br /> -<a href="http://llvm.org">LLVM Compiler Infrastructure</a><br /> - -Last modified: $Date: 2011-05-07 00:11:29 +0200 (Sat, 07 May 2011) $ -</address></div> -</div> -</div> -</body> -</html> |
