[llvm-commits] [llvm] r138602 - in /llvm/trunk: include/llvm/AutoUpgrade.h lib/VMCore/AutoUpgrade.cpp
Bill Wendling
isanbard at gmail.com
Thu Aug 25 16:22:41 PDT 2011
Author: void
Date: Thu Aug 25 18:22:40 2011
New Revision: 138602
URL: http://llvm.org/viewvc/llvm-project?rev=138602&view=rev
Log:
Initial check in that will auto-upgrade the old EH scheme to the new EH scheme.
This upgrade suffers from the problems of the old EH scheme - i.e., that the
calls to llvm.eh.exception() and llvm.eh.selector() can wander off and get
lost. It makes a valiant effort to reclaim these little lost lambs.
This is a first draft, so it hasn't yet been hooked up to the parser.
Modified:
llvm/trunk/include/llvm/AutoUpgrade.h
llvm/trunk/lib/VMCore/AutoUpgrade.cpp
Modified: llvm/trunk/include/llvm/AutoUpgrade.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/AutoUpgrade.h?rev=138602&r1=138601&r2=138602&view=diff
==============================================================================
--- llvm/trunk/include/llvm/AutoUpgrade.h (original)
+++ llvm/trunk/include/llvm/AutoUpgrade.h Thu Aug 25 18:22:40 2011
@@ -43,6 +43,10 @@
/// This function checks debug info intrinsics. If an intrinsic is invalid
/// then this function simply removes the intrinsic.
void CheckDebugInfoIntrinsics(Module *M);
+
+ /// This function upgrades the old pre-3.0 exception handling system to the
+ /// new one. N.B. This will be removed in 3.1.
+ void UpgradeExceptionHandling(Module *M);
} // End llvm namespace
#endif
Modified: llvm/trunk/lib/VMCore/AutoUpgrade.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/VMCore/AutoUpgrade.cpp?rev=138602&r1=138601&r2=138602&view=diff
==============================================================================
--- llvm/trunk/lib/VMCore/AutoUpgrade.cpp (original)
+++ llvm/trunk/lib/VMCore/AutoUpgrade.cpp Thu Aug 25 18:22:40 2011
@@ -14,11 +14,15 @@
#include "llvm/AutoUpgrade.h"
#include "llvm/Constants.h"
#include "llvm/Function.h"
+#include "llvm/Instruction.h"
#include "llvm/LLVMContext.h"
#include "llvm/Module.h"
#include "llvm/IntrinsicInst.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Support/CallSite.h"
+#include "llvm/Support/CFG.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/IRBuilder.h"
#include <cstring>
@@ -279,3 +283,200 @@
}
}
}
+
+/// FindExnAndSelIntrinsics - Find the eh_exception and eh_selector intrinsic
+/// calls reachable from the unwind basic block.
+static void FindExnAndSelIntrinsics(BasicBlock *BB, CallInst *&Exn,
+ CallInst *&Sel,
+ SmallPtrSet<BasicBlock*, 8> &Visited) {
+ if (!Visited.insert(BB)) return;
+
+ for (BasicBlock::iterator
+ I = BB->begin(), E = BB->end(); I != E; ++I) {
+ if (CallInst *CI = dyn_cast<CallInst>(I)) {
+ switch (CI->getCalledFunction()->getIntrinsicID()) {
+ default: break;
+ case Intrinsic::eh_exception:
+ assert(!Exn && "Found more than one eh.exception call!");
+ Exn = CI;
+ break;
+ case Intrinsic::eh_selector:
+ assert(!Sel && "Found more than one eh.selector call!");
+ Sel = CI;
+ break;
+ }
+
+ if (Exn && Sel) return;
+ }
+ }
+
+ if (Exn && Sel) return;
+
+ for (succ_iterator I = succ_begin(BB), E = succ_end(BB); I != E; ++I) {
+ FindExnAndSelIntrinsics(*I, Exn, Sel, Visited);
+ if (Exn && Sel) return;
+ }
+}
+
+/// TransferClausesToLandingPadInst - Transfer the exception handling clauses
+/// from the eh_selector call to the new landingpad instruction.
+static void TransferClausesToLandingPadInst(LandingPadInst *LPI,
+ CallInst *EHSel) {
+ LLVMContext &Context = LPI->getContext();
+ unsigned N = EHSel->getNumArgOperands();
+
+ for (unsigned i = N - 1; i > 1; --i) {
+ if (const ConstantInt *CI = dyn_cast<ConstantInt>(EHSel->getArgOperand(i))){
+ unsigned FilterLength = CI->getZExtValue();
+ unsigned FirstCatch = i + FilterLength + !FilterLength;
+ assert(FirstCatch <= N && "Invalid filter length");
+
+ if (FirstCatch < N)
+ for (unsigned j = FirstCatch; j < N; ++j) {
+ Value *Val = EHSel->getArgOperand(j);
+ if (!Val->hasName() || Val->getName() != "llvm.eh.catch.all.value") {
+ LPI->addClause(EHSel->getArgOperand(j));
+ } else {
+ GlobalVariable *GV = cast<GlobalVariable>(Val);
+ LPI->addClause(GV->getInitializer());
+ }
+ }
+
+ if (!FilterLength) {
+ // Cleanup.
+ LPI->setCleanup(true);
+ } else {
+ // Filter.
+ SmallVector<Constant *, 4> TyInfo;
+ TyInfo.reserve(FilterLength - 1);
+ for (unsigned j = i + 1; j < FirstCatch; ++j)
+ TyInfo.push_back(cast<Constant>(EHSel->getArgOperand(j)));
+ ArrayType *AType =
+ ArrayType::get(!TyInfo.empty() ? TyInfo[0]->getType() :
+ PointerType::getUnqual(Type::getInt8Ty(Context)),
+ TyInfo.size());
+ LPI->addClause(ConstantArray::get(AType, TyInfo));
+ }
+
+ N = i;
+ }
+ }
+
+ if (N > 2)
+ for (unsigned j = 2; j < N; ++j) {
+ Value *Val = EHSel->getArgOperand(j);
+ if (!Val->hasName() || Val->getName() != "llvm.eh.catch.all.value") {
+ LPI->addClause(EHSel->getArgOperand(j));
+ } else {
+ GlobalVariable *GV = cast<GlobalVariable>(Val);
+ LPI->addClause(GV->getInitializer());
+ }
+ }
+}
+
+/// This function upgrades the old pre-3.0 exception handling system to the new
+/// one. N.B. This will be removed in 3.1.
+void llvm::UpgradeExceptionHandling(Module *M) {
+ Function *EHException = M->getFunction("llvm.eh.exception");
+ Function *EHSelector = M->getFunction("llvm.eh.selector");
+ if (!EHException || !EHSelector)
+ return;
+
+ LLVMContext &Context = M->getContext();
+ Type *ExnTy = PointerType::getUnqual(Type::getInt8Ty(Context));
+ Type *SelTy = Type::getInt32Ty(Context);
+ Type *LPadSlotTy = StructType::get(ExnTy, SelTy, NULL);
+
+ // This map stores the slots where the exception object and selector value are
+ // stored within a function.
+ SmallVector<Instruction*, 32> DeadInsts;
+ DenseMap<Function*, std::pair<Value*, Value*> > FnToLPadSlotMap;
+ for (Module::iterator
+ I = M->begin(), E = M->end(); I != E; ++I) {
+ Function &F = *I;
+
+ for (Function::iterator
+ II = F.begin(), IE = F.end(); II != IE; ++II) {
+ BasicBlock *BB = &*II;
+ InvokeInst *Inst = dyn_cast<InvokeInst>(BB->getTerminator());
+ if (!Inst) continue;
+ BasicBlock *UnwindDest = Inst->getUnwindDest();
+ if (UnwindDest->isLandingPad()) continue; // All ready converted.
+
+ // Store the exception object and selector value in the entry block.
+ Value *ExnSlot = 0;
+ Value *SelSlot = 0;
+ if (!FnToLPadSlotMap[&F].first) {
+ BasicBlock *Entry = &F.front();
+ ExnSlot = new AllocaInst(ExnTy, "exn", Entry->getTerminator());
+ SelSlot = new AllocaInst(SelTy, "sel", Entry->getTerminator());
+ FnToLPadSlotMap[&F] = std::make_pair(ExnSlot, SelSlot);
+ } else {
+ ExnSlot = FnToLPadSlotMap[&F].first;
+ SelSlot = FnToLPadSlotMap[&F].second;
+ }
+
+ // We're in an unwind block. Try to find the eh.exception and eh.selector
+ // calls.
+ IRBuilder<> Builder(Context);
+ Builder.SetInsertPoint(UnwindDest, UnwindDest->getFirstNonPHI());
+
+ SmallPtrSet<BasicBlock*, 8> Visited;
+ CallInst *Exn = 0;
+ CallInst *Sel = 0;
+ FindExnAndSelIntrinsics(UnwindDest, Exn, Sel, Visited);
+ assert(Exn && Sel && "Cannot find eh.exception and eh.selector calls!");
+
+ Value *PersFn = Sel->getArgOperand(1);
+ LandingPadInst *LPI = Builder.CreateLandingPad(LPadSlotTy, PersFn, 0);
+ Value *LPExn = Builder.CreateExtractValue(LPI, 0);
+ Value *LPSel = Builder.CreateExtractValue(LPI, 1);
+ Builder.CreateStore(LPExn, ExnSlot);
+ Builder.CreateStore(LPSel, SelSlot);
+
+ TransferClausesToLandingPadInst(LPI, Sel);
+
+ Exn->replaceAllUsesWith(LPExn);
+ Sel->replaceAllUsesWith(LPSel);
+
+ DeadInsts.push_back(Exn);
+ DeadInsts.push_back(Sel);
+ }
+ }
+
+ // Remove the dead instructions.
+ while (!DeadInsts.empty()) {
+ Instruction *Inst = DeadInsts.pop_back_val();
+ Inst->eraseFromParent();
+ }
+
+ // Replace calls to "llvm.eh.resume" with the 'resume' instruction. Load the
+ // exception and selector values from the stored place.
+ Function *EHResume = M->getFunction("llvm.eh.resume");
+ if (!EHResume) return;
+
+ while (!EHResume->use_empty()) {
+ CallInst *Resume = cast<CallInst>(EHResume->use_back());
+ BasicBlock *BB = Resume->getParent();
+ Function *Fn = BB->getParent();
+ std::pair<Value*, Value*> &ExnSel = FnToLPadSlotMap[Fn];
+ IRBuilder<> Builder(Context);
+ Builder.SetInsertPoint(BB, Resume);
+
+ Value *Exn = Builder.CreateLoad(ExnSel.first, "exn");
+ Value *Sel = Builder.CreateLoad(ExnSel.second, "sel");
+
+ Value *LPadVal =
+ Builder.CreateInsertValue(UndefValue::get(LPadSlotTy),
+ Exn, 0, "lpad.val");
+ LPadVal = Builder.CreateInsertValue(LPadVal, Sel, 1, "lpad.val");
+ Builder.CreateResume(LPadVal);
+
+ // Remove all instructions after the 'resume.'
+ BasicBlock::iterator I = Resume;
+ while (I != BB->end()) {
+ Instruction *Inst = &*I++;
+ Inst->eraseFromParent();
+ }
+ }
+}
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