1 //===- DataStructure.cpp - Implement the core data structure analysis -----===//
3 // This file implements the core data structure functionality.
5 //===----------------------------------------------------------------------===//
7 #include "llvm/Module.h"
8 #include "llvm/DerivedTypes.h"
9 #include "Support/STLExtras.h"
10 #include "Support/StatisticReporter.h"
12 #include "llvm/Analysis/DataStructure.h"
14 AnalysisID LocalDataStructures::ID(AnalysisID::create<LocalDataStructures>());
16 //===----------------------------------------------------------------------===//
17 // DSNode Implementation
18 //===----------------------------------------------------------------------===//
20 DSNode::DSNode(enum NodeTy NT, const Type *T) : Ty(T), NodeType(NT) {
21 // If this node has any fields, allocate them now, but leave them null.
22 switch (T->getPrimitiveID()) {
23 case Type::PointerTyID: Links.resize(1); break;
24 case Type::ArrayTyID: Links.resize(1); break;
25 case Type::StructTyID:
26 Links.resize(cast<StructType>(T)->getNumContainedTypes());
32 // DSNode copy constructor... do not copy over the referrers list!
33 DSNode::DSNode(const DSNode &N)
34 : Ty(N.Ty), Links(N.Links), Globals(N.Globals), NodeType(N.NodeType) {
37 void DSNode::removeReferrer(DSNodeHandle *H) {
38 // Search backwards, because we depopulate the list from the back for
39 // efficiency (because it's a vector).
40 std::vector<DSNodeHandle*>::reverse_iterator I =
41 std::find(Referrers.rbegin(), Referrers.rend(), H);
42 assert(I != Referrers.rend() && "Referrer not pointing to node!");
43 Referrers.erase(I.base()-1);
46 // addGlobal - Add an entry for a global value to the Globals list. This also
47 // marks the node with the 'G' flag if it does not already have it.
49 void DSNode::addGlobal(GlobalValue *GV) {
50 // Keep the list sorted.
51 std::vector<GlobalValue*>::iterator I =
52 std::lower_bound(Globals.begin(), Globals.end(), GV);
54 if (I == Globals.end() || *I != GV) {
55 assert(GV->getType()->getElementType() == Ty);
56 Globals.insert(I, GV);
57 NodeType |= GlobalNode;
62 // addEdgeTo - Add an edge from the current node to the specified node. This
63 // can cause merging of nodes in the graph.
65 void DSNode::addEdgeTo(unsigned LinkNo, DSNode *N) {
66 assert(LinkNo < Links.size() && "LinkNo out of range!");
67 if (N == 0 || Links[LinkNo] == N) return; // Nothing to do
68 if (Links[LinkNo] == 0) { // No merging to perform
73 // Merge the two nodes...
74 Links[LinkNo]->mergeWith(N);
78 // mergeWith - Merge this node into the specified node, moving all links to and
79 // from the argument node into the current node. The specified node may be a
80 // null pointer (in which case, nothing happens).
82 void DSNode::mergeWith(DSNode *N) {
83 if (N == 0 || N == this) return; // Noop
84 assert(N->Ty == Ty && N->Links.size() == Links.size() &&
85 "Cannot merge nodes of two different types!");
87 // Remove all edges pointing at N, causing them to point to 'this' instead.
88 while (!N->Referrers.empty())
89 *N->Referrers.back() = this;
91 // Make all of the outgoing links of N now be outgoing links of this. This
92 // can cause recursive merging!
94 for (unsigned i = 0, e = Links.size(); i != e; ++i) {
95 addEdgeTo(i, N->Links[i]);
96 N->Links[i] = 0; // Reduce unneccesary edges in graph. N is dead
99 // Merge the node types
100 NodeType |= N->NodeType;
101 N->NodeType = 0; // N is now a dead node.
103 // Merge the globals list...
104 if (!N->Globals.empty()) {
105 // Save the current globals off to the side...
106 std::vector<GlobalValue*> OldGlobals(Globals);
108 // Resize the globals vector to be big enough to hold both of them...
109 Globals.resize(Globals.size()+N->Globals.size());
111 // Merge the two sorted globals lists together...
112 std::merge(OldGlobals.begin(), OldGlobals.end(),
113 N->Globals.begin(), N->Globals.end(), Globals.begin());
115 // Erase duplicate entries from the globals list...
116 Globals.erase(std::unique(Globals.begin(), Globals.end()), Globals.end());
118 // Delete the globals from the old node...
123 //===----------------------------------------------------------------------===//
124 // DSGraph Implementation
125 //===----------------------------------------------------------------------===//
127 DSGraph::DSGraph(const DSGraph &G) : Func(G.Func) {
128 RetNode = cloneInto(G, ValueMap, false);
131 DSGraph::~DSGraph() {
132 FunctionCalls.clear();
137 // Drop all intra-node references, so that assertions don't fail...
138 std::for_each(Nodes.begin(), Nodes.end(),
139 std::mem_fun(&DSNode::dropAllReferences));
142 // Delete all of the nodes themselves...
143 std::for_each(Nodes.begin(), Nodes.end(), deleter<DSNode>);
146 // dump - Allow inspection of graph in a debugger.
147 void DSGraph::dump() const { print(std::cerr); }
149 // cloneInto - Clone the specified DSGraph into the current graph, returning the
150 // Return node of the graph. The translated ValueMap for the old function is
151 // filled into the OldValMap member. If StripLocals is set to true, Scalar and
152 // Alloca markers are removed from the graph, as the graph is being cloned into
153 // a calling function's graph.
155 DSNode *DSGraph::cloneInto(const DSGraph &G,
156 std::map<Value*, DSNodeHandle> &OldValMap,
158 std::map<const DSNode*, DSNode*> NodeMap;
159 NodeMap[0] = 0; // Null pointer maps to null
161 unsigned FN = Nodes.size(); // FirstNode...
163 // Duplicate all of the nodes, populating the node map...
164 Nodes.reserve(FN+G.Nodes.size());
165 for (unsigned i = 0, e = G.Nodes.size(); i != e; ++i) {
166 DSNode *Old = G.Nodes[i], *New = new DSNode(*Old);
167 Nodes.push_back(New);
171 // Rewrite the links in the nodes to point into the current graph now.
172 for (unsigned i = FN, e = Nodes.size(); i != e; ++i)
173 for (unsigned j = 0, e = Nodes[i]->getNumLinks(); j != e; ++j)
174 Nodes[i]->setLink(j, NodeMap[Nodes[i]->getLink(j)]);
176 // If we are inlining this graph into the called function graph, remove local
179 for (unsigned i = FN, e = Nodes.size(); i != e; ++i)
180 Nodes[i]->NodeType &= ~(DSNode::AllocaNode | DSNode::ScalarNode);
182 // Copy the value map...
183 for (std::map<Value*, DSNodeHandle>::const_iterator I = G.ValueMap.begin(),
184 E = G.ValueMap.end(); I != E; ++I)
185 OldValMap[I->first] = NodeMap[I->second];
187 // Copy the function calls list...
188 unsigned FC = FunctionCalls.size(); // FirstCall
189 FunctionCalls.reserve(FC+G.FunctionCalls.size());
190 for (unsigned i = 0, e = G.FunctionCalls.size(); i != e; ++i) {
191 FunctionCalls.push_back(std::vector<DSNodeHandle>());
192 FunctionCalls[FC+i].reserve(G.FunctionCalls[i].size());
193 for (unsigned j = 0, e = G.FunctionCalls[i].size(); j != e; ++j)
194 FunctionCalls[FC+i].push_back(NodeMap[G.FunctionCalls[i][j]]);
197 // Return the returned node pointer...
198 return NodeMap[G.RetNode];
202 // markIncompleteNodes - Mark the specified node as having contents that are not
203 // known with the current analysis we have performed. Because a node makes all
204 // of the nodes it can reach imcomplete if the node itself is incomplete, we
205 // must recursively traverse the data structure graph, marking all reachable
206 // nodes as incomplete.
208 static void markIncompleteNode(DSNode *N) {
209 // Stop recursion if no node, or if node already marked...
210 if (N == 0 || (N->NodeType & DSNode::Incomplete)) return;
212 // Actually mark the node
213 N->NodeType |= DSNode::Incomplete;
215 // Recusively process children...
216 for (unsigned i = 0, e = N->getNumLinks(); i != e; ++i)
217 markIncompleteNode(N->getLink(i));
221 // markIncompleteNodes - Traverse the graph, identifying nodes that may be
222 // modified by other functions that have not been resolved yet. This marks
223 // nodes that are reachable through three sources of "unknownness":
225 // Global Variables, Function Calls, and Incoming Arguments
227 // For any node that may have unknown components (because something outside the
228 // scope of current analysis may have modified it), the 'Incomplete' flag is
229 // added to the NodeType.
231 void DSGraph::markIncompleteNodes() {
232 // Mark any incoming arguments as incomplete...
233 for (Function::aiterator I = Func.abegin(), E = Func.aend(); I != E; ++I)
234 if (isa<PointerType>(I->getType()))
235 markIncompleteNode(ValueMap[I]->getLink(0));
237 // Mark stuff passed into functions calls as being incomplete...
238 for (unsigned i = 0, e = FunctionCalls.size(); i != e; ++i) {
239 std::vector<DSNodeHandle> &Args = FunctionCalls[i];
240 if (Args[0]) // If the call returns a pointer...
241 // Then the return value is certainly incomplete!
242 markIncompleteNode(Args[0]);
244 // The call does not make the function argument incomplete...
246 // All arguments to the function call are incomplete though!
247 for (unsigned i = 2, e = Args.size(); i != e; ++i)
248 markIncompleteNode(Args[i]);
251 // Mark all of the nodes pointed to by global nodes as incomplete...
252 for (unsigned i = 0, e = Nodes.size(); i != e; ++i)
253 if (Nodes[i]->NodeType & DSNode::GlobalNode) {
254 DSNode *N = Nodes[i];
255 for (unsigned i = 0, e = N->getNumLinks(); i != e; ++i)
256 markIncompleteNode(N->getLink(i));
260 // isNodeDead - This method checks to see if a node is dead, and if it isn't, it
261 // checks to see if there are simple transformations that it can do to make it
264 bool DSGraph::isNodeDead(DSNode *N) {
265 // Is it a trivially dead shadow node...
266 if (N->getReferrers().empty() && N->NodeType == 0)
269 // Is it a function node or some other trivially unused global?
270 if ((N->NodeType & ~DSNode::GlobalNode) == 0 &&
271 N->getNumLinks() == 0 &&
272 N->getReferrers().size() == N->getGlobals().size()) {
274 // Remove the globals from the valuemap, so that the referrer count will go
276 while (!N->getGlobals().empty()) {
277 GlobalValue *GV = N->getGlobals().back();
278 N->getGlobals().pop_back();
281 assert(N->getReferrers().empty() && "Referrers should all be gone now!");
289 // removeDeadNodes - After the graph has been constructed, this method removes
290 // all unreachable nodes that are created because they got merged with other
291 // nodes in the graph. These nodes will all be trivially unreachable, so we
292 // don't have to perform any non-trivial analysis here.
294 void DSGraph::removeDeadNodes() {
295 for (unsigned i = 0; i != Nodes.size(); ++i)
296 if (isNodeDead(Nodes[i])) { // This node is dead!
297 delete Nodes[i]; // Free memory...
298 Nodes.erase(Nodes.begin()+i--); // Remove from node list...
301 // Remove identical function calls
302 unsigned NumFns = FunctionCalls.size();
303 std::sort(FunctionCalls.begin(), FunctionCalls.end());
304 FunctionCalls.erase(std::unique(FunctionCalls.begin(), FunctionCalls.end()),
305 FunctionCalls.end());
307 DEBUG(if (NumFns != FunctionCalls.size())
308 std::cerr << "Merged " << (NumFns-FunctionCalls.size())
309 << " call nodes in " << Func.getName() << "\n";);
313 // maskNodeTypes - Apply a mask to all of the node types in the graph. This
314 // is useful for clearing out markers like Scalar or Incomplete.
316 void DSGraph::maskNodeTypes(unsigned char Mask) {
317 for (unsigned i = 0, e = Nodes.size(); i != e; ++i)
318 Nodes[i]->NodeType &= Mask;
322 //===----------------------------------------------------------------------===//
323 // LocalDataStructures Implementation
324 //===----------------------------------------------------------------------===//
326 // releaseMemory - If the pass pipeline is done with this pass, we can release
327 // our memory... here...
329 void LocalDataStructures::releaseMemory() {
330 for (std::map<Function*, DSGraph*>::iterator I = DSInfo.begin(),
331 E = DSInfo.end(); I != E; ++I)
334 // Empty map so next time memory is released, data structures are not
339 bool LocalDataStructures::run(Module &M) {
340 // Calculate all of the graphs...
341 for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
342 if (!I->isExternal())
343 DSInfo.insert(std::make_pair(&*I, new DSGraph(*I)));