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Linker: Eliminate uncalled functions, because they can be ill-defined.

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Fixes issue #610. Also provides a testing option to keep uncalled functions.
This commit is contained in:
John Kessenich 2016-12-09 19:22:20 -07:00
parent bf6d7f43fd
commit 906cc21816
68 changed files with 101 additions and 7783 deletions
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26
glslang/MachineIndependent/linkValidate.cpp
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@ -377,7 +377,7 @@ void TIntermediate::mergeErrorCheck(TInfoSink& infoSink, const TIntermSymbol& sy
//
// Also, lock in defaults of things not set, including array sizes.
//
void TIntermediate::finalCheck(TInfoSink& infoSink)
void TIntermediate::finalCheck(TInfoSink& infoSink, bool keepUncalled)
{
if (getTreeRoot() == nullptr)
return;
@ -394,7 +394,7 @@ void TIntermediate::finalCheck(TInfoSink& infoSink)
// recursion and missing body checking
checkCallGraphCycles(infoSink);
checkCallGraphBodies(infoSink);
checkCallGraphBodies(infoSink, keepUncalled);
// overlap/alias/missing I/O, etc.
inOutLocationCheck(infoSink);
@ -583,23 +583,27 @@ void TIntermediate::checkCallGraphCycles(TInfoSink& infoSink)
//
// See which functions are reachable from the entry point and which have bodies.
// Reachable ones with missing bodies are errors.
// Unreachable bodies are dead code.
//
void TIntermediate::checkCallGraphBodies(TInfoSink& infoSink)
void TIntermediate::checkCallGraphBodies(TInfoSink& infoSink, bool keepUncalled)
{
// Clear fields we'll use for this.
for (TGraph::iterator call = callGraph.begin(); call != callGraph.end(); ++call) {
call->visited = false;
call->calleeBodyPosition = -1;
}
// The top level of the AST includes function definitions (bodies).
// Compare these to function calls in the call graph.
// We'll end up knowing which have bodies, and if so,
// how to map the call-graph node to the location in the AST.
TIntermSequence &functionSequence = getTreeRoot()->getAsAggregate()->getSequence();
std::vector<bool> reachable(functionSequence.size(), true); // so that non-functions are reachable
for (int f = 0; f < (int)functionSequence.size(); ++f) {
glslang::TIntermAggregate* node = functionSequence[f]->getAsAggregate();
if (node && (node->getOp() == glslang::EOpFunction)) {
if (node->getName().compare(getEntryPointMangledName().c_str()) != 0)
reachable[f] = false; // so that function bodies are unreachable, until proven otherwise
for (TGraph::iterator call = callGraph.begin(); call != callGraph.end(); ++call) {
if (call->callee == node->getName())
call->calleeBodyPosition = f;
@ -638,9 +642,21 @@ void TIntermediate::checkCallGraphBodies(TInfoSink& infoSink)
if (call->calleeBodyPosition == -1) {
error(infoSink, "No function definition (body) found: ");
infoSink.info << " " << call->callee << "\n";
}
} else
reachable[call->calleeBodyPosition] = true;
}
}
// Bodies in the AST not reached by the call graph are dead;
// clear them out, since they can't be reached and also can't
// be translated further due to possibility of being ill defined.
if (! keepUncalled) {
for (int f = 0; f < (int)functionSequence.size(); ++f) {
if (! reachable[f])
functionSequence[f] = nullptr;
}
functionSequence.erase(std::remove(functionSequence.begin(), functionSequence.end(), nullptr), functionSequence.end());
}
}
//