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Grow the EQ classes for globals at the end of the BU pass. This shrinks

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memory usage in the TD pass for 254.gap from 31.3MB to 3.9MB.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@20834 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2005-03-25 16:45:43 +00:00
parent dbcc2f7b0b
commit 33b4276053
1 changed files with 93 additions and 0 deletions
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93
lib/Analysis/DataStructure/BottomUpClosure.cpp
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@ -30,6 +30,88 @@ namespace {
X("budatastructure", "Bottom-up Data Structure Analysis");
}
/// BuildGlobalECs - Look at all of the nodes in the globals graph. If any node
/// contains multiple globals, DSA will never, ever, be able to tell the globals
/// apart. Instead of maintaining this information in all of the graphs
/// throughout the entire program, store only a single global (the "leader") in
/// the graphs, and build equivalence classes for the rest of the globals.
static void BuildGlobalECs(DSGraph &GG, std::set<GlobalValue*> &ECGlobals) {
DSScalarMap &SM = GG.getScalarMap();
EquivalenceClasses<GlobalValue*> &GlobalECs = SM.getGlobalECs();
for (DSGraph::node_iterator I = GG.node_begin(), E = GG.node_end();
I != E; ++I) {
if (I->getGlobalsList().size() <= 1) continue;
// First, build up the equivalence set for this block of globals.
const std::vector<GlobalValue*> &GVs = I->getGlobalsList();
GlobalValue *First = GVs[0];
for (unsigned i = 1, e = GVs.size(); i != e; ++i)
GlobalECs.unionSets(First, GVs[i]);
// Next, get the leader element.
assert(First == GlobalECs.getLeaderValue(First) &&
"First did not end up being the leader?");
// Next, remove all globals from the scalar map that are not the leader.
assert(GVs[0] == First && "First had to be at the front!");
for (unsigned i = 1, e = GVs.size(); i != e; ++i) {
ECGlobals.insert(GVs[i]);
SM.erase(SM.find(GVs[i]));
}
// Finally, change the global node to only contain the leader.
I->clearGlobals();
I->addGlobal(First);
}
DEBUG(GG.AssertGraphOK());
}
/// EliminateUsesOfECGlobals - Once we have determined that some globals are in
/// really just equivalent to some other globals, remove the globals from the
/// specified DSGraph (if present), and merge any nodes with their leader nodes.
static void EliminateUsesOfECGlobals(DSGraph &G,
const std::set<GlobalValue*> &ECGlobals) {
DSScalarMap &SM = G.getScalarMap();
EquivalenceClasses<GlobalValue*> &GlobalECs = SM.getGlobalECs();
bool MadeChange = false;
for (DSScalarMap::global_iterator GI = SM.global_begin(), E = SM.global_end();
GI != E; ) {
GlobalValue *GV = *GI++;
if (!ECGlobals.count(GV)) continue;
const DSNodeHandle &GVNH = SM[GV];
assert(!GVNH.isNull() && "Global has null NH!?");
// Okay, this global is in some equivalence class. Start by finding the
// leader of the class.
GlobalValue *Leader = GlobalECs.getLeaderValue(GV);
// If the leader isn't already in the graph, insert it into the node
// corresponding to GV.
if (!SM.global_count(Leader)) {
GVNH.getNode()->addGlobal(Leader);
SM[Leader] = GVNH;
} else {
// Otherwise, the leader is in the graph, make sure the nodes are the
// merged in the specified graph.
const DSNodeHandle &LNH = SM[Leader];
if (LNH.getNode() != GVNH.getNode())
LNH.mergeWith(GVNH);
}
// Next step, remove the global from the DSNode.
GVNH.getNode()->removeGlobal(GV);
// Finally, remove the global from the ScalarMap.
SM.erase(GV);
MadeChange = true;
}
DEBUG(if(MadeChange) G.AssertGraphOK());
}
// run - Calculate the bottom up data structure graphs for each function in the
// program.
//
@ -85,6 +167,17 @@ bool BUDataStructures::runOnModule(Module &M) {
// Mark external globals incomplete.
GlobalsGraph->markIncompleteNodes(DSGraph::IgnoreGlobals);
// Grow the equivalence classes for the globals to include anything that we
// now know to be aliased.
std::set<GlobalValue*> ECGlobals;
BuildGlobalECs(*GlobalsGraph, ECGlobals);
if (!ECGlobals.empty()) {
DEBUG(std::cerr << "Eliminating " << ECGlobals.size() << " EC Globals!\n");
for (hash_map<Function*, DSGraph*>::iterator I = DSInfo.begin(),
E = DSInfo.end(); I != E; ++I)
EliminateUsesOfECGlobals(*I->second, ECGlobals);
}
// Merge the globals variables (not the calls) from the globals graph back
// into the main function's graph so that the main function contains all of
// the information about global pools and GV usage in the program.