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Fix recursion detection (it was detecting cycles in the call graph that were not directed cycles).

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git-svn-id: https://cvs.khronos.org/svn/repos/ogl/trunk/ecosystem/public/sdk/tools/glslang@23761 e7fa87d3-cd2b-0410-9028-fcbf551c1848
This commit is contained in:
John Kessenich 2013-10-30 01:22:04 +00:00
parent d492aafad7
commit 8cbd18ecaa
4 changed files with 153 additions and 20 deletions
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41
glslang/MachineIndependent/linkValidate.cpp
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@ -259,7 +259,7 @@ void TIntermediate::checkCallGraphCycles(TInfoSink& infoSink)
// Reset everything, once.
for (TGraph::iterator call = callGraph.begin(); call != callGraph.end(); ++call) {
call->visited = false;
call->subGraph = false;
call->currentPath = false;
call->errorGiven = false;
}
@ -284,42 +284,49 @@ void TIntermediate::checkCallGraphCycles(TInfoSink& infoSink)
// Otherwise, we found a new subgraph, process it:
// See what all can be reached by this new root, and if any of
// that is recursive. This is done by marking processed calls as active,
// and if a new call is found that is already active, we looped,
// that is recursive. This is done by depth-first traversals, seeing
// if a new call is found that was already in the currentPath (a back edge),
// thereby detecting recursion.
std::list<TCall*> stack;
newRoot->currentPath = true; // currentPath will be true iff it is on the stack
stack.push_back(newRoot);
newRoot->subGraph = true;
while (! stack.empty()) {
// get a caller
TCall* call = stack.back();
stack.pop_back();
// Add to the stack all the callees of the last subgraph node popped from the stack.
// This algorithm always terminates, because only subGraph == false causes a push
// and all pushes change subGraph to true, and nothing changes subGraph to false.
for (TGraph::iterator child = callGraph.begin(); child != callGraph.end(); ++child) {
// Add to the stack just one callee.
// This algorithm always terminates, because only ! visited and ! currentPath causes a push
// and all pushes change currentPath to true, and all pops change visited to true.
TGraph::iterator child = callGraph.begin();
for (; child != callGraph.end(); ++child) {
// If we already visited this node, its whole subgraph has already been processed, so skip it.
if (child->visited)
continue;
if (call->callee == child->caller) {
if (child->subGraph) {
if (child->currentPath) {
// Then, we found a back edge
if (! child->errorGiven) {
error(infoSink, "Recursion detected:");
infoSink.info << " " << call->callee << " calling " << child->callee << "\n";
child->errorGiven = true;
}
} else {
child->subGraph = true;
child->currentPath = true;
stack.push_back(&(*child));
break;
}
}
}
if (child == callGraph.end()) {
// no more callees, we bottomed out, never look at this node again
stack.back()->currentPath = false;
stack.back()->visited = true;
stack.pop_back();
}
} // end while, meaning nothing left to process in this subtree
// Mark all the subGraph nodes as visited, closing out this subgraph.
for (TGraph::iterator call = callGraph.begin(); call != callGraph.end(); ++call) {
if (call->subGraph)
call->visited = true;
}
} while (newRoot); // redundant loop check; should always exit via the 'break' above
}