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<pre><a name="line-1"></a>
<a name="line-2"></a><span class='hs-comment'>-- | Types for the general graph colorer.</span>
<a name="line-3"></a>
<a name="line-4"></a><span class='hs-keyword'>module</span> <span class='hs-conid'>GraphBase</span> <span class='hs-layout'>(</span>
<a name="line-5"></a> <span class='hs-conid'>Triv</span><span class='hs-layout'>,</span>
<a name="line-6"></a> <span class='hs-conid'>Graph</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span>
<a name="line-7"></a> <span class='hs-varid'>initGraph</span><span class='hs-layout'>,</span>
<a name="line-8"></a> <span class='hs-varid'>graphMapModify</span><span class='hs-layout'>,</span>
<a name="line-9"></a>
<a name="line-10"></a> <span class='hs-conid'>Node</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <span class='hs-varid'>newNode</span><span class='hs-layout'>,</span>
<a name="line-11"></a><span class='hs-layout'>)</span>
<a name="line-12"></a>
<a name="line-13"></a>
<a name="line-14"></a><span class='hs-keyword'>where</span>
<a name="line-15"></a>
<a name="line-16"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>UniqSet</span>
<a name="line-17"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>UniqFM</span>
<a name="line-18"></a>
<a name="line-19"></a>
<a name="line-20"></a><a name="Triv"></a><span class='hs-comment'>-- | A fn to check if a node is trivially colorable</span>
<a name="line-21"></a><a name="Triv"></a><span class='hs-comment'>-- For graphs who's color classes are disjoint then a node is 'trivially colorable'</span>
<a name="line-22"></a><a name="Triv"></a><span class='hs-comment'>-- when it has less neighbors and exclusions than available colors for that node.</span>
<a name="line-23"></a><a name="Triv"></a><span class='hs-comment'>--</span>
<a name="line-24"></a><a name="Triv"></a><span class='hs-comment'>-- For graph's who's color classes overlap, ie some colors alias other colors, then</span>
<a name="line-25"></a><a name="Triv"></a><span class='hs-comment'>-- this can be a bit more tricky. There is a general way to calculate this, but </span>
<a name="line-26"></a><a name="Triv"></a><span class='hs-comment'>-- it's likely be too slow for use in the code. The coloring algorithm takes</span>
<a name="line-27"></a><a name="Triv"></a><span class='hs-comment'>-- a canned function which can be optimised by the user to be specific to the </span>
<a name="line-28"></a><a name="Triv"></a><span class='hs-comment'>-- specific graph being colored.</span>
<a name="line-29"></a><a name="Triv"></a><span class='hs-comment'>--</span>
<a name="line-30"></a><a name="Triv"></a><span class='hs-comment'>-- for details, see "A Generalised Algorithm for Graph-Coloring Register Allocation"</span>
<a name="line-31"></a><a name="Triv"></a><span class='hs-comment'>-- Smith, Ramsey, Holloway - PLDI 2004.</span>
<a name="line-32"></a><a name="Triv"></a><span class='hs-comment'>--</span>
<a name="line-33"></a><a name="Triv"></a><span class='hs-keyword'>type</span> <span class='hs-conid'>Triv</span> <span class='hs-varid'>k</span> <span class='hs-varid'>cls</span> <span class='hs-varid'>color</span>
<a name="line-34"></a> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>cls</span> <span class='hs-comment'>-- the class of the node we're trying to color.</span>
<a name="line-35"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>UniqSet</span> <span class='hs-varid'>k</span> <span class='hs-comment'>-- the node's neighbors.</span>
<a name="line-36"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>UniqSet</span> <span class='hs-varid'>color</span> <span class='hs-comment'>-- the node's exclusions.</span>
<a name="line-37"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Bool</span>
<a name="line-38"></a>
<a name="line-39"></a>
<a name="line-40"></a><a name="Graph"></a><span class='hs-comment'>-- | The Interference graph.</span>
<a name="line-41"></a><a name="Graph"></a><span class='hs-comment'>-- There used to be more fields, but they were turfed out in a previous revision.</span>
<a name="line-42"></a><a name="Graph"></a><span class='hs-comment'>-- maybe we'll want more later..</span>
<a name="line-43"></a><a name="Graph"></a><span class='hs-comment'>--</span>
<a name="line-44"></a><a name="Graph"></a><span class='hs-keyword'>data</span> <span class='hs-conid'>Graph</span> <span class='hs-varid'>k</span> <span class='hs-varid'>cls</span> <span class='hs-varid'>color</span>
<a name="line-45"></a> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Graph</span> <span class='hs-layout'>{</span>
<a name="line-46"></a> <span class='hs-comment'>-- | All active nodes in the graph.</span>
<a name="line-47"></a> <span class='hs-varid'>graphMap</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>UniqFM</span> <span class='hs-layout'>(</span><span class='hs-conid'>Node</span> <span class='hs-varid'>k</span> <span class='hs-varid'>cls</span> <span class='hs-varid'>color</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-48"></a>
<a name="line-49"></a>
<a name="line-50"></a><a name="initGraph"></a><span class='hs-comment'>-- | An empty graph. </span>
<a name="line-51"></a><span class='hs-definition'>initGraph</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Graph</span> <span class='hs-varid'>k</span> <span class='hs-varid'>cls</span> <span class='hs-varid'>color</span>
<a name="line-52"></a><span class='hs-definition'>initGraph</span>
<a name="line-53"></a> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Graph</span>
<a name="line-54"></a> <span class='hs-layout'>{</span> <span class='hs-varid'>graphMap</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>emptyUFM</span> <span class='hs-layout'>}</span>
<a name="line-55"></a>
<a name="line-56"></a>
<a name="line-57"></a><a name="graphMapModify"></a><span class='hs-comment'>-- | Modify the finite map holding the nodes in the graph.</span>
<a name="line-58"></a><span class='hs-definition'>graphMapModify</span>
<a name="line-59"></a> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>UniqFM</span> <span class='hs-layout'>(</span><span class='hs-conid'>Node</span> <span class='hs-varid'>k</span> <span class='hs-varid'>cls</span> <span class='hs-varid'>color</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>UniqFM</span> <span class='hs-layout'>(</span><span class='hs-conid'>Node</span> <span class='hs-varid'>k</span> <span class='hs-varid'>cls</span> <span class='hs-varid'>color</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-60"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Graph</span> <span class='hs-varid'>k</span> <span class='hs-varid'>cls</span> <span class='hs-varid'>color</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Graph</span> <span class='hs-varid'>k</span> <span class='hs-varid'>cls</span> <span class='hs-varid'>color</span>
<a name="line-61"></a>
<a name="line-62"></a><span class='hs-definition'>graphMapModify</span> <span class='hs-varid'>f</span> <span class='hs-varid'>graph</span>
<a name="line-63"></a> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>graph</span> <span class='hs-layout'>{</span> <span class='hs-varid'>graphMap</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>f</span> <span class='hs-layout'>(</span><span class='hs-varid'>graphMap</span> <span class='hs-varid'>graph</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-64"></a>
<a name="line-65"></a>
<a name="line-66"></a>
<a name="line-67"></a><a name="Node"></a><span class='hs-comment'>-- | Graph nodes.</span>
<a name="line-68"></a><a name="Node"></a><span class='hs-comment'>-- Represents a thing that can conflict with another thing.</span>
<a name="line-69"></a><a name="Node"></a><span class='hs-comment'>-- For the register allocater the nodes represent registers.</span>
<a name="line-70"></a><a name="Node"></a><span class='hs-comment'>--</span>
<a name="line-71"></a><a name="Node"></a><span class='hs-keyword'>data</span> <span class='hs-conid'>Node</span> <span class='hs-varid'>k</span> <span class='hs-varid'>cls</span> <span class='hs-varid'>color</span>
<a name="line-72"></a> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Node</span> <span class='hs-layout'>{</span>
<a name="line-73"></a> <span class='hs-comment'>-- | A unique identifier for this node.</span>
<a name="line-74"></a> <span class='hs-varid'>nodeId</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>k</span>
<a name="line-75"></a>
<a name="line-76"></a> <span class='hs-comment'>-- | The class of this node,</span>
<a name="line-77"></a> <span class='hs-comment'>-- determines the set of colors that can be used.</span>
<a name="line-78"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>nodeClass</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>cls</span>
<a name="line-79"></a>
<a name="line-80"></a> <span class='hs-comment'>-- | The color of this node, if any.</span>
<a name="line-81"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>nodeColor</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Maybe</span> <span class='hs-varid'>color</span>
<a name="line-82"></a>
<a name="line-83"></a> <span class='hs-comment'>-- | Neighbors which must be colored differently to this node.</span>
<a name="line-84"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>nodeConflicts</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>UniqSet</span> <span class='hs-varid'>k</span>
<a name="line-85"></a>
<a name="line-86"></a> <span class='hs-comment'>-- | Colors that cannot be used by this node.</span>
<a name="line-87"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>nodeExclusions</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>UniqSet</span> <span class='hs-varid'>color</span>
<a name="line-88"></a>
<a name="line-89"></a> <span class='hs-comment'>-- | Colors that this node would prefer to be, in decending order.</span>
<a name="line-90"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>nodePreference</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>color</span><span class='hs-keyglyph'>]</span>
<a name="line-91"></a>
<a name="line-92"></a> <span class='hs-comment'>-- | Neighbors that this node would like to be colored the same as.</span>
<a name="line-93"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>nodeCoalesce</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>UniqSet</span> <span class='hs-varid'>k</span> <span class='hs-layout'>}</span>
<a name="line-94"></a>
<a name="line-95"></a>
<a name="line-96"></a><a name="newNode"></a><span class='hs-comment'>-- | An empty node.</span>
<a name="line-97"></a><span class='hs-definition'>newNode</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>k</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>cls</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Node</span> <span class='hs-varid'>k</span> <span class='hs-varid'>cls</span> <span class='hs-varid'>color</span>
<a name="line-98"></a><span class='hs-definition'>newNode</span> <span class='hs-varid'>k</span> <span class='hs-varid'>cls</span>
<a name="line-99"></a> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Node</span>
<a name="line-100"></a> <span class='hs-layout'>{</span> <span class='hs-varid'>nodeId</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>k</span>
<a name="line-101"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>nodeClass</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>cls</span>
<a name="line-102"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>nodeColor</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Nothing</span>
<a name="line-103"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>nodeConflicts</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>emptyUniqSet</span>
<a name="line-104"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>nodeExclusions</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>emptyUniqSet</span>
<a name="line-105"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>nodePreference</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>[]</span>
<a name="line-106"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>nodeCoalesce</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>emptyUniqSet</span> <span class='hs-layout'>}</span>
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