[llvm-commits] [poolalloc] r112574 - /poolalloc/trunk/lib/DSA/CompleteBottomUp.cpp

[Arushi Aggarwal]

Author: aggarwa4
Date: Mon Aug 30 23:15:49 2010
New Revision: 112574

URL: http://llvm.org/viewvc/llvm-project?rev=112574&view=rev
Log:
 Fix for dsa/regression/2010-07-16.CBU_MissingGraph.ll. The DSCallGraph replaced the call targets of an indirect function call site with the leader of the SCC, in which the callee lies. CBU would then look for an entry for the leader in the GlobalsGraph, which did not exist because the leader of the SCC was never address taken. The fix, goes through all functions, in the SCC of the callees at a call site, and merges all the functions that have entries in the GlobalsGraph

Modified:
    poolalloc/trunk/lib/DSA/CompleteBottomUp.cpp

Modified: poolalloc/trunk/lib/DSA/CompleteBottomUp.cpp
URL: http://llvm.org/viewvc/llvm-project/poolalloc/trunk/lib/DSA/CompleteBottomUp.cpp?rev=112574&r1=112573&r2=112574&view=diff
==============================================================================
--- poolalloc/trunk/lib/DSA/CompleteBottomUp.cpp (original)
+++ poolalloc/trunk/lib/DSA/CompleteBottomUp.cpp Mon Aug 30 23:15:49 2010
@@ -88,6 +88,14 @@
 #ifndef NDEBUG
     // --Verify that for every callee of an indirect function call
     //   we have an entry in the GlobalsGraph
+
+    // If any function in an SCC is a callee of an indirect function
+    // call, the DScallgraph contains the leader of the SCC as the 
+    // callee of the indirect call. 
+    // The leasder of the SCC may not have an entry in the Globals
+    // Graph, but at least one of the functions in the SCC
+    // should have an entry in the GlobalsGraph
+
     bool isIndirect = ((*ii).getCalledFunction() == NULL);
 
     if (isIndirect) {
@@ -101,9 +109,16 @@
         // class leader instead of the global itself.
         //
         const Function * F = *csii;
-        if (!(F->isDeclaration()))
-          assert (SM.count (SM.getLeaderForGlobal(F)) &&
+        if (!(F->isDeclaration())){
+          DSCallGraph::scc_iterator sccii = callgraph.scc_begin(F),
+                                    sccee = callgraph.scc_end(F);
+          bool flag = false;
+          for(; sccii != sccee; ++sccii) {
+            flag |= SM.count(SM.getLeaderForGlobal(*sccii)); 
+          } 
+          assert (flag &&
                   "Indirect function callee not in globals?");
+         }
       }
 
     }
@@ -131,23 +146,55 @@
     DSCallGraph::callee_iterator csi = callgraph.callee_begin(*ii),
             cse = callgraph.callee_end(*ii);
 
-    // Grab the first callee we have an entry for...
-    while (csi != cse && !SM.count(*csi))
+    
+    // We get all the callees, and then for all functions in that SCC, find the 
+    // ones that have entries in the GlobalsGraph. 
+
+    // We merge all the functions in the SCC that have entries, and then move
+    // on to the next callee and repeat.
+
+    // If an SCC has functions that have entries in the GlobalsGraph, and are 
+    // targets of an indirect function call site, they will be merged.
+   
+    // However, if an SCC has functions, that have entries in the GlobalsGraph, 
+    // bur are not the targets of an indirect function call site, they will not 
+    // be merged by CBU.
+    
+    DSNodeHandle SrcNH;
+    while(csi != cse) {
+      const Function *F = *csi;
+      DSCallGraph::scc_iterator sccii = callgraph.scc_begin(F),
+                                sccee = callgraph.scc_end(F);
+      while(sccii != sccee && SM.find(*sccii) == SM.end()) {
+        ++sccii; 
+      }
+      if(sccii == sccee) {
+        ++csi;
+        continue;
+      }
+      DSNodeHandle SrcNH = SM.find(*sccii)->second;
+      ++sccii;
+      for(;sccii != sccee; ++sccii) {
+        DSGraph::ScalarMapTy::const_iterator I = SM.find(*sccii);
+        if (I != SM.end()) {
+          SrcNH.mergeWith(I->second);
+        }
+      }
       ++csi;
-
-    //
-    // If we have no entries, we're done.  Move on to the next call site.
-    //
-    if (csi == cse) continue;
-
-    DSNodeHandle& SrcNH = SM.find(*csi)->second;
-
-    // Merge the rest of the callees (that we have entries for) together
-    // with the first one.
-    for (; csi != cse; ++csi) {
-      if (SM.count(*csi)) {
-        SrcNH.mergeWith(SM.find(*csi)->second);
+      break;
+    }
+    
+    while(csi != cse) {
+      const Function *F = *csi;
+      DSCallGraph::scc_iterator sccii = callgraph.scc_begin(F),
+                                sccee = callgraph.scc_end(F);
+      for(;sccii != sccee; ++sccii) {
+        DSGraph::ScalarMapTy::const_iterator I = SM.find(*sccii);
+        if (I != SM.end()) {
+          SrcNH.mergeWith(I->second);
+        }
       }
+      ++csi;
     }
   }
 }