#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Support/CFG.h"
-#include "llvm/Support/Compiler.h"
#include <set>
#include <algorithm>
using namespace llvm;
STATISTIC(NumUnreach, "Number of noreturn calls optimized");
namespace {
- struct VISIBILITY_HIDDEN PruneEH : public CallGraphSCCPass {
+ struct PruneEH : public CallGraphSCCPass {
static char ID; // Pass identification, replacement for typeid
- PruneEH() : CallGraphSCCPass(&ID) {}
+ PruneEH() : CallGraphSCCPass(ID) {}
// runOnSCC - Analyze the SCC, performing the transformation if possible.
- bool runOnSCC(const std::vector<CallGraphNode *> &SCC);
+ bool runOnSCC(CallGraphSCC &SCC);
bool SimplifyFunction(Function *F);
void DeleteBasicBlock(BasicBlock *BB);
}
char PruneEH::ID = 0;
-static RegisterPass<PruneEH>
-X("prune-eh", "Remove unused exception handling info");
+INITIALIZE_PASS(PruneEH, "prune-eh",
+ "Remove unused exception handling info", false, false);
Pass *llvm::createPruneEHPass() { return new PruneEH(); }
-bool PruneEH::runOnSCC(const std::vector<CallGraphNode *> &SCC) {
+bool PruneEH::runOnSCC(CallGraphSCC &SCC) {
SmallPtrSet<CallGraphNode *, 8> SCCNodes;
CallGraph &CG = getAnalysis<CallGraph>();
bool MadeChange = false;
// Fill SCCNodes with the elements of the SCC. Used for quickly
// looking up whether a given CallGraphNode is in this SCC.
- for (unsigned i = 0, e = SCC.size(); i != e; ++i)
- SCCNodes.insert(SCC[i]);
+ for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end(); I != E; ++I)
+ SCCNodes.insert(*I);
// First pass, scan all of the functions in the SCC, simplifying them
// according to what we know.
- for (unsigned i = 0, e = SCC.size(); i != e; ++i)
- if (Function *F = SCC[i]->getFunction())
+ for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end(); I != E; ++I)
+ if (Function *F = (*I)->getFunction())
MadeChange |= SimplifyFunction(F);
// Next, check to see if any callees might throw or if there are any external
// obviously the SCC might throw.
//
bool SCCMightUnwind = false, SCCMightReturn = false;
- for (unsigned i = 0, e = SCC.size();
- (!SCCMightUnwind || !SCCMightReturn) && i != e; ++i) {
- Function *F = SCC[i]->getFunction();
+ for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end();
+ (!SCCMightUnwind || !SCCMightReturn) && I != E; ++I) {
+ Function *F = (*I)->getFunction();
if (F == 0) {
SCCMightUnwind = true;
SCCMightReturn = true;
// If the SCC doesn't unwind or doesn't throw, note this fact.
if (!SCCMightUnwind || !SCCMightReturn)
- for (unsigned i = 0, e = SCC.size(); i != e; ++i) {
+ for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end(); I != E; ++I) {
Attributes NewAttributes = Attribute::None;
if (!SCCMightUnwind)
if (!SCCMightReturn)
NewAttributes |= Attribute::NoReturn;
- const AttrListPtr &PAL = SCC[i]->getFunction()->getAttributes();
+ Function *F = (*I)->getFunction();
+ const AttrListPtr &PAL = F->getAttributes();
const AttrListPtr &NPAL = PAL.addAttr(~0, NewAttributes);
if (PAL != NPAL) {
MadeChange = true;
- SCC[i]->getFunction()->setAttributes(NPAL);
+ F->setAttributes(NPAL);
}
}
- for (unsigned i = 0, e = SCC.size(); i != e; ++i) {
+ for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end(); I != E; ++I) {
// Convert any invoke instructions to non-throwing functions in this node
// into call instructions with a branch. This makes the exception blocks
// dead.
- if (Function *F = SCC[i]->getFunction())
+ if (Function *F = (*I)->getFunction())
MadeChange |= SimplifyFunction(F);
}
// function if we have invokes to non-unwinding functions or code after calls to
// no-return functions.
bool PruneEH::SimplifyFunction(Function *F) {
- CallGraph &CG = getAnalysis<CallGraph>();
- CallGraphNode *CGN = CG[F];
-
bool MadeChange = false;
for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
if (InvokeInst *II = dyn_cast<InvokeInst>(BB->getTerminator()))
if (II->doesNotThrow()) {
- SmallVector<Value*, 8> Args(II->op_begin()+3, II->op_end());
+ SmallVector<Value*, 8> Args(II->op_begin(), II->op_end() - 3);
// Insert a call instruction before the invoke.
CallInst *Call = CallInst::Create(II->getCalledValue(),
Args.begin(), Args.end(), "", II);
Call->setAttributes(II->getAttributes());
// Anything that used the value produced by the invoke instruction
- // now uses the value produced by the call instruction.
+ // now uses the value produced by the call instruction. Note that we
+ // do this even for void functions and calls with no uses so that the
+ // callgraph edge is updated.
II->replaceAllUsesWith(Call);
BasicBlock *UnwindBlock = II->getUnwindDest();
UnwindBlock->removePredecessor(II->getParent());
- // Fix up the call graph.
- CGN->replaceCallSite(II, Call);
-
// Insert a branch to the normal destination right before the
// invoke.
BranchInst::Create(II->getNormalDest(), II);
// Remove the uncond branch and add an unreachable.
BB->getInstList().pop_back();
- new UnreachableInst(BB);
+ new UnreachableInst(BB->getContext(), BB);
DeleteBasicBlock(New); // Delete the new BB.
MadeChange = true;