Added comments.
Added FIXME regarding how the call graph fixup probably isn't needed
anymore.
No functionality changes.
llvm-svn: 88056
diff --git a/safecode/lib/ArrayBoundChecks/BottomUpCallGraph.cpp b/safecode/lib/ArrayBoundChecks/BottomUpCallGraph.cpp
index 78a8cb7..16a1fa6 100755
--- a/safecode/lib/ArrayBoundChecks/BottomUpCallGraph.cpp
+++ b/safecode/lib/ArrayBoundChecks/BottomUpCallGraph.cpp
@@ -7,6 +7,16 @@
//
//===----------------------------------------------------------------------===//
//
+// I believe this pass does two things:
+// o) It attempts to improve upon the call graph calculated by DSA for those
+// call sites in which a callee was not found.
+// o) It finds functions that are part of Strongly Connected Components (SCCs)
+// in the call graph and marks them being a part of an SCC.
+//
+// FIXME:
+// I believe the fixup of the call graph is no longer necessary; DSA asserts
+// if it can't find a callee for a call instruction.
+//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "bucg"
@@ -25,6 +35,7 @@
using namespace llvm;
namespace llvm {
+
char BottomUpCallGraph::ID = 0;
//
@@ -106,34 +117,46 @@
}
-void BottomUpCallGraph::visit(Function *f) {
+void
+BottomUpCallGraph::visit (Function *f) {
if (Visited.find(f) == Visited.end()) {
- //Have not visited it before
+ // Record that we have now visited this function
Visited.insert(f);
- //not visited implies it won't be there on the stack anyways, so push it
- //on stack
+
+ //
+ // If we have not visited this function before, that implies that the
+ // function won't be on the stack; therefore, push it on stack
+ //
Stack.push_back(f);
+
+ //
+ // Visit all the functions that can call this function.
+ //
if (FuncCallSiteMap.count(f)) {
std::vector<CallSite> & callsitelist = FuncCallSiteMap[f];
for (unsigned idx = 0, sz = callsitelist.size(); idx != sz; ++idx) {
- Function *parent = callsitelist[idx].getInstruction()->getParent()->getParent();
- visit(parent);
+ Function *parent = callsitelist[idx].getInstruction()->getParent()
+ ->getParent();
+ visit(parent);
}
}
Stack.pop_back();
} else {
- //Have already visited it, check if it forms SCC
- std::vector<Function*>::iterator res = std::find(Stack.begin(), Stack.end(), f);
+ // We have already visited this function; check if it forms an SCC
+ std::vector<Function*>::iterator res = std::find (Stack.begin(),
+ Stack.end(),
+ f);
if (res != Stack.end()) {
- //Cycle detected.
+ // Cycle detected.
for (; res != Stack.end() ; ++res) {
- SccList.insert(*res);
+ SccList.insert(*res);
}
}
}
}
-void BottomUpCallGraph::figureOutSCCs(Module &M) {
+void
+BottomUpCallGraph::figureOutSCCs (Module &M) {
for (Module::iterator I = M.begin(), E= M.end(); I != E ; ++I) {
visit(I);
}
