[llvm-commits] [llvm] r79250 - in /llvm/trunk: include/llvm/CodeGen/Passes.h lib/CodeGen/AsmPrinter/DwarfException.cpp lib/CodeGen/AsmPrinter/DwarfException.h lib/CodeGen/LLVMTargetMachine.cpp lib/CodeGen/SjLjEHPrepare.cpp
Jim Grosbach
grosbach at apple.com
Mon Aug 17 09:41:22 PDT 2009
Author: grosbach
Date: Mon Aug 17 11:41:22 2009
New Revision: 79250
URL: http://llvm.org/viewvc/llvm-project?rev=79250&view=rev
Log:
Move the sjlj exception handling conversions to a back-end pass where they
more properly belong. This allows removing the front-end conditionalized
SJLJ code, and cleans up the generated IR considerably. All of the
infrastructure code (calling _Unwind_SjLj_Register/Unregister, etc) is
added by the SjLjEHPrepare pass.
Added:
llvm/trunk/lib/CodeGen/SjLjEHPrepare.cpp
Modified:
llvm/trunk/include/llvm/CodeGen/Passes.h
llvm/trunk/lib/CodeGen/AsmPrinter/DwarfException.cpp
llvm/trunk/lib/CodeGen/AsmPrinter/DwarfException.h
llvm/trunk/lib/CodeGen/LLVMTargetMachine.cpp
Modified: llvm/trunk/include/llvm/CodeGen/Passes.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/Passes.h?rev=79250&r1=79249&r2=79250&view=diff
==============================================================================
--- llvm/trunk/include/llvm/CodeGen/Passes.h (original)
+++ llvm/trunk/include/llvm/CodeGen/Passes.h Mon Aug 17 11:41:22 2009
@@ -193,6 +193,10 @@
/// adapted to code generation. Required if using dwarf exception handling.
FunctionPass *createDwarfEHPass(const TargetLowering *tli, bool fast);
+ /// createSjLjEHPass - This pass adapts exception handling code to use
+ /// the GCC-style builtin setjmp/longjmp (sjlj) to handling EH control flow.
+ FunctionPass *createSjLjEHPass(const TargetLowering *tli);
+
} // End llvm namespace
#endif
Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfException.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfException.cpp?rev=79250&r1=79249&r2=79250&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfException.cpp (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfException.cpp Mon Aug 17 11:41:22 2009
@@ -364,7 +364,6 @@
/// try-range address.
void DwarfException::
ComputeCallSiteTable(SmallVectorImpl<CallSiteEntry> &CallSites,
- std::map<unsigned,CallSiteEntry*> &CallSiteIndexMap,
const RangeMapType &PadMap,
const SmallVectorImpl<const LandingPadInfo *> &LandingPads,
const SmallVectorImpl<unsigned> &FirstActions) {
@@ -438,12 +437,6 @@
// Otherwise, create a new call-site.
CallSites.push_back(Site);
- // For SjLj handling, map the call site entry to its index
- if (TAI->getExceptionHandlingType() == ExceptionHandling::SjLj) {
- unsigned Index =
- MF->getLandingPadCallSiteIndex(LandingPad->LandingPadBlock);
- CallSiteIndexMap[Index] = &CallSites.back();
- }
PreviousIsInvoke = true;
} else {
// Create a gap.
@@ -520,9 +513,7 @@
// Compute the call-site table.
SmallVector<CallSiteEntry, 64> CallSites;
- std::map<unsigned,CallSiteEntry*> CallSiteIndexMap;
- ComputeCallSiteTable(CallSites, CallSiteIndexMap, PadMap,
- LandingPads, FirstActions);
+ ComputeCallSiteTable(CallSites, PadMap, LandingPads, FirstActions);
// Final tallies.
@@ -537,8 +528,7 @@
if (TAI->getExceptionHandlingType() == ExceptionHandling::SjLj) {
- SizeSites = (MF->getMaxCallSiteIndex() - CallSites.size()) *
- TargetAsmInfo::getULEB128Size(0) * 2;
+ SizeSites = 0;
} else
SizeSites = CallSites.size() *
(SiteStartSize + SiteLengthSize + LandingPadSize);
@@ -546,7 +536,6 @@
SizeSites += TargetAsmInfo::getULEB128Size(CallSites[i].Action);
if (TAI->getExceptionHandlingType() == ExceptionHandling::SjLj)
SizeSites += TargetAsmInfo::getULEB128Size(i);
- // FIXME: 'i' above should be the landing pad index
}
// Type infos.
const unsigned TypeInfoSize = TD->getPointerSize(); // DW_EH_PE_absptr
@@ -655,25 +644,11 @@
assert(MF->getCallSiteCount() == CallSites.size());
// Emit the landing pad site information.
- // SjLj handling assigned the call site indices in the front end, so
- // we need to make sure the table here lines up with that. That's pretty
- // horrible, and should be fixed ASAP to do that stuff in the back end
- // instead.
- std::map<unsigned, CallSiteEntry*>::const_iterator I, E;
- I = CallSiteIndexMap.begin();
- E = CallSiteIndexMap.end();
- for (unsigned CurrIdx = 1; I != E; ++I) {
- // paranoia.
- assert(CurrIdx <= I->first);
- // Fill in any gaps in the table
- while (CurrIdx++ < I->first) {
- Asm->EmitULEB128Bytes(0);
- Asm->EOL("Filler landing pad");
- Asm->EmitULEB128Bytes(0);
- Asm->EOL("Filler action");
- }
- const CallSiteEntry &S = *(I->second);
- Asm->EmitULEB128Bytes(I->first - 1);
+ unsigned idx = 0;
+ for (SmallVectorImpl<CallSiteEntry>::const_iterator
+ I = CallSites.begin(), E = CallSites.end(); I != E; ++I, ++idx) {
+ const CallSiteEntry &S = *I;
+ Asm->EmitULEB128Bytes(idx);
Asm->EOL("Landing pad");
Asm->EmitULEB128Bytes(S.Action);
Asm->EOL("Action");
Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfException.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfException.h?rev=79250&r1=79249&r2=79250&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfException.h (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfException.h Mon Aug 17 11:41:22 2009
@@ -155,7 +155,6 @@
/// of any entry - they form gaps in the table. Entries must be ordered by
/// try-range address.
void ComputeCallSiteTable(SmallVectorImpl<CallSiteEntry> &CallSites,
- std::map<unsigned,CallSiteEntry*> &CallSiteIndexMap,
const RangeMapType &PadMap,
const SmallVectorImpl<const LandingPadInfo *> &LPs,
const SmallVectorImpl<unsigned> &FirstActions);
Modified: llvm/trunk/lib/CodeGen/LLVMTargetMachine.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/LLVMTargetMachine.cpp?rev=79250&r1=79249&r2=79250&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/LLVMTargetMachine.cpp (original)
+++ llvm/trunk/lib/CodeGen/LLVMTargetMachine.cpp Mon Aug 17 11:41:22 2009
@@ -241,8 +241,11 @@
// handle.
switch (getTargetAsmInfo()->getExceptionHandlingType())
{
- // SjLj piggy-backs on dwarf for this bit
case ExceptionHandling::SjLj:
+ // SjLj piggy-backs on dwarf for this bit. The cleanups done apply to both
+ PM.add(createDwarfEHPass(getTargetLowering(), OptLevel==CodeGenOpt::None));
+ PM.add(createSjLjEHPass(getTargetLowering()));
+ break;
case ExceptionHandling::Dwarf:
PM.add(createDwarfEHPass(getTargetLowering(), OptLevel==CodeGenOpt::None));
break;
Added: llvm/trunk/lib/CodeGen/SjLjEHPrepare.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SjLjEHPrepare.cpp?rev=79250&view=auto
==============================================================================
--- llvm/trunk/lib/CodeGen/SjLjEHPrepare.cpp (added)
+++ llvm/trunk/lib/CodeGen/SjLjEHPrepare.cpp Mon Aug 17 11:41:22 2009
@@ -0,0 +1,527 @@
+//===- SjLjEHPass.cpp - Eliminate Invoke & Unwind instructions -----------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This transformation is designed for use by code generators which use SjLj
+// based exception handling.
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "sjljehprepare"
+#include "llvm/Transforms/Scalar.h"
+#include "llvm/Constants.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/Instructions.h"
+#include "llvm/Intrinsics.h"
+#include "llvm/LLVMContext.h"
+#include "llvm/Module.h"
+#include "llvm/Pass.h"
+#include "llvm/CodeGen/Passes.h"
+#include "llvm/Transforms/Utils/BasicBlockUtils.h"
+#include "llvm/Transforms/Utils/Local.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Compiler.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Target/TargetLowering.h"
+#include <set>
+using namespace llvm;
+
+STATISTIC(NumInvokes, "Number of invokes replaced");
+STATISTIC(NumUnwinds, "Number of unwinds replaced");
+STATISTIC(NumSpilled, "Number of registers live across unwind edges");
+
+namespace {
+ class VISIBILITY_HIDDEN SjLjEHPass : public FunctionPass {
+
+ const TargetLowering *TLI;
+
+ const Type *FunctionContextTy;
+ Constant *RegisterFn;
+ Constant *UnregisterFn;
+ Constant *ResumeFn;
+ Constant *BuiltinSetjmpFn;
+ Constant *FrameAddrFn;
+ Constant *LSDAAddrFn;
+ Value *PersonalityFn;
+ Constant *Selector32Fn;
+ Constant *Selector64Fn;
+ Constant *ExceptionFn;
+
+ Value *CallSite;
+ public:
+ static char ID; // Pass identification, replacement for typeid
+ explicit SjLjEHPass(const TargetLowering *tli = NULL)
+ : FunctionPass(&ID), TLI(tli) { }
+ bool doInitialization(Module &M);
+ bool runOnFunction(Function &F);
+
+ virtual void getAnalysisUsage(AnalysisUsage &AU) const { }
+ const char *getPassName() const {
+ return "SJLJ Exception Handling preparation";
+ }
+
+ private:
+ void markInvokeCallSite(InvokeInst *II, unsigned InvokeNo,
+ Value *CallSite,
+ SwitchInst *CatchSwitch);
+ void splitLiveRangesLiveAcrossInvokes(std::vector<InvokeInst*> &Invokes);
+ bool insertSjLjEHSupport(Function &F);
+ };
+} // end anonymous namespace
+
+char SjLjEHPass::ID = 0;
+
+// Public Interface To the SjLjEHPass pass.
+FunctionPass *llvm::createSjLjEHPass(const TargetLowering *TLI) {
+ return new SjLjEHPass(TLI);
+}
+// doInitialization - Make sure that there is a prototype for abort in the
+// current module.
+bool SjLjEHPass::doInitialization(Module &M) {
+ // Build the function context structure.
+ // builtin_setjmp uses a five word jbuf
+ const Type *VoidPtrTy =
+ PointerType::getUnqual(Type::getInt8Ty(M.getContext()));
+ const Type *Int32Ty = Type::getInt32Ty(M.getContext());
+ FunctionContextTy =
+ StructType::get(M.getContext(),
+ VoidPtrTy, // __prev
+ Int32Ty, // call_site
+ ArrayType::get(Int32Ty, 4), // __data
+ VoidPtrTy, // __personality
+ VoidPtrTy, // __lsda
+ ArrayType::get(VoidPtrTy, 5), // __jbuf
+ NULL);
+ RegisterFn = M.getOrInsertFunction("_Unwind_SjLj_Register",
+ Type::getVoidTy(M.getContext()),
+ PointerType::getUnqual(FunctionContextTy),
+ (Type *)0);
+ UnregisterFn =
+ M.getOrInsertFunction("_Unwind_SjLj_Unregister",
+ Type::getVoidTy(M.getContext()),
+ PointerType::getUnqual(FunctionContextTy),
+ (Type *)0);
+ ResumeFn =
+ M.getOrInsertFunction("_Unwind_SjLj_Resume",
+ Type::getVoidTy(M.getContext()),
+ VoidPtrTy,
+ (Type *)0);
+ FrameAddrFn = Intrinsic::getDeclaration(&M, Intrinsic::frameaddress);
+ BuiltinSetjmpFn = Intrinsic::getDeclaration(&M, Intrinsic::eh_sjlj_setjmp);
+ LSDAAddrFn = Intrinsic::getDeclaration(&M, Intrinsic::eh_sjlj_lsda);
+ Selector32Fn = Intrinsic::getDeclaration(&M, Intrinsic::eh_selector_i32);
+ Selector64Fn = Intrinsic::getDeclaration(&M, Intrinsic::eh_selector_i64);
+ ExceptionFn = Intrinsic::getDeclaration(&M, Intrinsic::eh_exception);
+
+ return true;
+}
+
+/// markInvokeCallSite - Insert code to mark the call_site for this invoke
+void SjLjEHPass::markInvokeCallSite(InvokeInst *II, unsigned InvokeNo,
+ Value *CallSite,
+ SwitchInst *CatchSwitch) {
+ ConstantInt *CallSiteNoC= ConstantInt::get(Type::getInt32Ty(II->getContext()),
+ InvokeNo);
+ // The runtime comes back to the dispatcher with the call_site - 1 in
+ // the context. Odd, but there it is.
+ ConstantInt *SwitchValC = ConstantInt::get(Type::getInt32Ty(II->getContext()),
+ InvokeNo - 1);
+
+ // If the unwind edge has phi nodes, split the edge.
+ if (isa<PHINode>(II->getUnwindDest()->begin())) {
+ SplitCriticalEdge(II, 1, this);
+
+ // If there are any phi nodes left, they must have a single predecessor.
+ while (PHINode *PN = dyn_cast<PHINode>(II->getUnwindDest()->begin())) {
+ PN->replaceAllUsesWith(PN->getIncomingValue(0));
+ PN->eraseFromParent();
+ }
+ }
+
+ // Insert a store of the invoke num before the invoke and store zero into the
+ // location afterward.
+ new StoreInst(CallSiteNoC, CallSite, true, II); // volatile
+
+ // Add a switch case to our unwind block.
+ CatchSwitch->addCase(SwitchValC, II->getUnwindDest());
+ // We still want this to look like an invoke so we emit the LSDA properly
+ // FIXME: ??? Or will this cause strangeness with mis-matched IDs like
+ // when it was in the front end?
+}
+
+/// MarkBlocksLiveIn - Insert BB and all of its predescessors into LiveBBs until
+/// we reach blocks we've already seen.
+static void MarkBlocksLiveIn(BasicBlock *BB, std::set<BasicBlock*> &LiveBBs) {
+ if (!LiveBBs.insert(BB).second) return; // already been here.
+
+ for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI)
+ MarkBlocksLiveIn(*PI, LiveBBs);
+}
+
+// live across unwind edges. Each value that is live across an unwind edge
+// we spill into a stack location, guaranteeing that there is nothing live
+// across the unwind edge. This process also splits all critical edges
+// coming out of invoke's.
+void SjLjEHPass::
+splitLiveRangesLiveAcrossInvokes(std::vector<InvokeInst*> &Invokes) {
+ // First step, split all critical edges from invoke instructions.
+ for (unsigned i = 0, e = Invokes.size(); i != e; ++i) {
+ InvokeInst *II = Invokes[i];
+ SplitCriticalEdge(II, 0, this);
+ SplitCriticalEdge(II, 1, this);
+ assert(!isa<PHINode>(II->getNormalDest()) &&
+ !isa<PHINode>(II->getUnwindDest()) &&
+ "critical edge splitting left single entry phi nodes?");
+ }
+
+ Function *F = Invokes.back()->getParent()->getParent();
+
+ // To avoid having to handle incoming arguments specially, we lower each arg
+ // to a copy instruction in the entry block. This ensures that the argument
+ // value itself cannot be live across the entry block.
+ BasicBlock::iterator AfterAllocaInsertPt = F->begin()->begin();
+ while (isa<AllocaInst>(AfterAllocaInsertPt) &&
+ isa<ConstantInt>(cast<AllocaInst>(AfterAllocaInsertPt)->getArraySize()))
+ ++AfterAllocaInsertPt;
+ for (Function::arg_iterator AI = F->arg_begin(), E = F->arg_end();
+ AI != E; ++AI) {
+ // This is always a no-op cast because we're casting AI to AI->getType() so
+ // src and destination types are identical. BitCast is the only possibility.
+ CastInst *NC = new BitCastInst(
+ AI, AI->getType(), AI->getName()+".tmp", AfterAllocaInsertPt);
+ AI->replaceAllUsesWith(NC);
+ // Normally its is forbidden to replace a CastInst's operand because it
+ // could cause the opcode to reflect an illegal conversion. However, we're
+ // replacing it here with the same value it was constructed with to simply
+ // make NC its user.
+ NC->setOperand(0, AI);
+ }
+
+ // Finally, scan the code looking for instructions with bad live ranges.
+ for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
+ for (BasicBlock::iterator II = BB->begin(), E = BB->end(); II != E; ++II) {
+ // Ignore obvious cases we don't have to handle. In particular, most
+ // instructions either have no uses or only have a single use inside the
+ // current block. Ignore them quickly.
+ Instruction *Inst = II;
+ if (Inst->use_empty()) continue;
+ if (Inst->hasOneUse() &&
+ cast<Instruction>(Inst->use_back())->getParent() == BB &&
+ !isa<PHINode>(Inst->use_back())) continue;
+
+ // If this is an alloca in the entry block, it's not a real register
+ // value.
+ if (AllocaInst *AI = dyn_cast<AllocaInst>(Inst))
+ if (isa<ConstantInt>(AI->getArraySize()) && BB == F->begin())
+ continue;
+
+ // Avoid iterator invalidation by copying users to a temporary vector.
+ std::vector<Instruction*> Users;
+ for (Value::use_iterator UI = Inst->use_begin(), E = Inst->use_end();
+ UI != E; ++UI) {
+ Instruction *User = cast<Instruction>(*UI);
+ if (User->getParent() != BB || isa<PHINode>(User))
+ Users.push_back(User);
+ }
+
+ // Scan all of the uses and see if the live range is live across an unwind
+ // edge. If we find a use live across an invoke edge, create an alloca
+ // and spill the value.
+ std::set<InvokeInst*> InvokesWithStoreInserted;
+
+ // Find all of the blocks that this value is live in.
+ std::set<BasicBlock*> LiveBBs;
+ LiveBBs.insert(Inst->getParent());
+ while (!Users.empty()) {
+ Instruction *U = Users.back();
+ Users.pop_back();
+
+ if (!isa<PHINode>(U)) {
+ MarkBlocksLiveIn(U->getParent(), LiveBBs);
+ } else {
+ // Uses for a PHI node occur in their predecessor block.
+ PHINode *PN = cast<PHINode>(U);
+ for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
+ if (PN->getIncomingValue(i) == Inst)
+ MarkBlocksLiveIn(PN->getIncomingBlock(i), LiveBBs);
+ }
+ }
+
+ // Now that we know all of the blocks that this thing is live in, see if
+ // it includes any of the unwind locations.
+ bool NeedsSpill = false;
+ for (unsigned i = 0, e = Invokes.size(); i != e; ++i) {
+ BasicBlock *UnwindBlock = Invokes[i]->getUnwindDest();
+ if (UnwindBlock != BB && LiveBBs.count(UnwindBlock)) {
+ NeedsSpill = true;
+ }
+ }
+
+ // If we decided we need a spill, do it.
+ if (NeedsSpill) {
+ ++NumSpilled;
+ DemoteRegToStack(*Inst, true);
+ }
+ }
+}
+
+bool SjLjEHPass::insertSjLjEHSupport(Function &F) {
+ std::vector<ReturnInst*> Returns;
+ std::vector<UnwindInst*> Unwinds;
+ std::vector<InvokeInst*> Invokes;
+
+ // Look through the terminators of the basic blocks to find invokes, returns
+ // and unwinds
+ for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
+ if (ReturnInst *RI = dyn_cast<ReturnInst>(BB->getTerminator())) {
+ // Remember all return instructions in case we insert an invoke into this
+ // function.
+ Returns.push_back(RI);
+ } else if (InvokeInst *II = dyn_cast<InvokeInst>(BB->getTerminator())) {
+ Invokes.push_back(II);
+ } else if (UnwindInst *UI = dyn_cast<UnwindInst>(BB->getTerminator())) {
+ Unwinds.push_back(UI);
+ }
+ // If we don't have any invokes or unwinds, there's nothing to do.
+ if (Unwinds.empty() && Invokes.empty()) return false;
+
+ NumInvokes += Invokes.size();
+ NumUnwinds += Unwinds.size();
+
+
+ if (!Invokes.empty()) {
+ // We have invokes, so we need to add register/unregister calls to get
+ // this function onto the global unwind stack.
+ //
+ // First thing we need to do is scan the whole function for values that are
+ // live across unwind edges. Each value that is live across an unwind edge
+ // we spill into a stack location, guaranteeing that there is nothing live
+ // across the unwind edge. This process also splits all critical edges
+ // coming out of invoke's.
+ splitLiveRangesLiveAcrossInvokes(Invokes);
+
+ BasicBlock *EntryBB = F.begin();
+ // Create an alloca for the incoming jump buffer ptr and the new jump buffer
+ // that needs to be restored on all exits from the function. This is an
+ // alloca because the value needs to be added to the global context list.
+ unsigned Align = 4; // FIXME: Should be a TLI check?
+ AllocaInst *FunctionContext =
+ new AllocaInst(FunctionContextTy, 0, Align,
+ "fcn_context", F.begin()->begin());
+
+ Value *Idxs[2];
+ const Type *Int32Ty = Type::getInt32Ty(F.getContext());
+ Value *Zero = ConstantInt::get(Int32Ty, 0);
+ // We need to also keep around a reference to the call_site field
+ Idxs[0] = Zero;
+ Idxs[1] = ConstantInt::get(Int32Ty, 1);
+ CallSite = GetElementPtrInst::Create(FunctionContext, Idxs, Idxs+2,
+ "call_site",
+ EntryBB->getTerminator());
+
+ // The exception selector comes back in context->data[1]
+ Idxs[1] = ConstantInt::get(Int32Ty, 2);
+ Value *FCData = GetElementPtrInst::Create(FunctionContext, Idxs, Idxs+2,
+ "fc_data",
+ EntryBB->getTerminator());
+ Idxs[1] = ConstantInt::get(Int32Ty, 1);
+ Value *SelectorAddr = GetElementPtrInst::Create(FCData, Idxs, Idxs+2,
+ "exc_selector_gep",
+ EntryBB->getTerminator());
+ // The exception value comes back in context->data[0]
+ Idxs[1] = Zero;
+ Value *ExceptionAddr = GetElementPtrInst::Create(FCData, Idxs, Idxs+2,
+ "exception_gep",
+ EntryBB->getTerminator());
+
+ // Find the eh.selector.* and eh.exception calls. We'll use the first
+ // ex.selector to determine the right personality function to use. For
+ // SJLJ, we always use the same personality for the whole function,
+ // not on a per-selector basis.
+ // FIXME: That's a bit ugly. Better way?
+ std::vector<CallInst*> EH_Selectors;
+ std::vector<CallInst*> EH_Exceptions;
+ for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
+ // for (unsigned i = 0, e = Invokes.size(); i != e; ++i) {
+// BasicBlock *Pad = Invokes[0]->getUnwindDest();
+ for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) {
+ if (CallInst *CI = dyn_cast<CallInst>(I)) {
+ if (CI->getCalledFunction() == Selector32Fn ||
+ CI->getCalledFunction() == Selector64Fn) {
+ if (!PersonalityFn) PersonalityFn = CI->getOperand(2);
+ EH_Selectors.push_back(CI);
+ } else if (CI->getCalledFunction() == ExceptionFn) {
+ EH_Exceptions.push_back(CI);
+ }
+ }
+ }
+ }
+ // The result of the eh.selector call will be replaced with a
+ // a reference to the selector value returned in the function
+ // context. We leave the selector itself so the EH analysis later
+ // can use it.
+ for (int i = 0, e = EH_Selectors.size(); i < e; ++i) {
+ CallInst *I = EH_Selectors[i];
+ Value *SelectorVal = new LoadInst(SelectorAddr, "select_val", true, I);
+ I->replaceAllUsesWith(SelectorVal);
+ }
+ // eh.exception calls are replaced with references to the proper
+ // location in the context. Unlike eh.selector, the eh.exception
+ // calls are removed entirely.
+ for (int i = 0, e = EH_Exceptions.size(); i < e; ++i) {
+ CallInst *I = EH_Exceptions[i];
+ // Possible for there to be duplicates, so check to make sure
+ // the instruction hasn't already been removed.
+ if (!I->getParent()) continue;
+ Value *Val = new LoadInst(ExceptionAddr, "exception", true, I);
+ Val = CastInst::Create(Instruction::IntToPtr, Val,
+ PointerType::getUnqual(Type::getInt8Ty(F.getContext())),
+ "", I);
+
+ I->replaceAllUsesWith(Val);
+ I->eraseFromParent();
+ }
+
+
+
+
+ // The entry block changes to have the eh.sjlj.setjmp, with a conditional
+ // branch to a dispatch block for non-zero returns. If we return normally,
+ // we're not handling an exception and just register the function context
+ // and continue.
+
+ // Create the dispatch block. The dispatch block is basically a big switch
+ // statement that goes to all of the invoke landing pads.
+ BasicBlock *DispatchBlock =
+ BasicBlock::Create(F.getContext(), "eh.sjlj.setjmp.catch", &F);
+
+ // Insert a load in the Catch block, and a switch on its value. By default,
+ // we go to a block that just does an unwind (which is the correct action
+ // for a standard call).
+ BasicBlock *UnwindBlock = BasicBlock::Create(F.getContext(), "unwindbb", &F);
+ Unwinds.push_back(new UnwindInst(F.getContext(), UnwindBlock));
+
+ Value *DispatchLoad = new LoadInst(CallSite, "invoke.num", true,
+ DispatchBlock);
+ SwitchInst *DispatchSwitch =
+ SwitchInst::Create(DispatchLoad, UnwindBlock, Invokes.size(), DispatchBlock);
+ // Split the entry block to insert the conditional branch for the setjmp.
+ BasicBlock *ContBlock = EntryBB->splitBasicBlock(EntryBB->getTerminator(),
+ "eh.sjlj.setjmp.cont");
+
+ // Populate the Function Context
+ // 1. LSDA address
+ // 2. Personality function address
+ // 3. jmpbuf (save FP and call eh.sjlj.setjmp)
+
+ // LSDA address
+ Idxs[0] = Zero;
+ Idxs[1] = ConstantInt::get(Int32Ty, 4);
+ Value *LSDAFieldPtr =
+ GetElementPtrInst::Create(FunctionContext, Idxs, Idxs+2,
+ "lsda_gep",
+ EntryBB->getTerminator());
+ Value *LSDA = CallInst::Create(LSDAAddrFn, "lsda_addr",
+ EntryBB->getTerminator());
+ new StoreInst(LSDA, LSDAFieldPtr, true, EntryBB->getTerminator());
+
+ Idxs[1] = ConstantInt::get(Int32Ty, 3);
+ Value *PersonalityFieldPtr =
+ GetElementPtrInst::Create(FunctionContext, Idxs, Idxs+2,
+ "lsda_gep",
+ EntryBB->getTerminator());
+ new StoreInst(PersonalityFn, PersonalityFieldPtr, true,
+ EntryBB->getTerminator());
+
+ // Save the frame pointer.
+ Idxs[1] = ConstantInt::get(Int32Ty, 5);
+ Value *FieldPtr
+ = GetElementPtrInst::Create(FunctionContext, Idxs, Idxs+2,
+ "jbuf_gep",
+ EntryBB->getTerminator());
+ Idxs[1] = ConstantInt::get(Int32Ty, 0);
+ Value *ElemPtr =
+ GetElementPtrInst::Create(FieldPtr, Idxs, Idxs+2, "jbuf_fp_gep",
+ EntryBB->getTerminator());
+
+ Value *Val = CallInst::Create(FrameAddrFn,
+ ConstantInt::get(Int32Ty, 0),
+ "fp",
+ EntryBB->getTerminator());
+ new StoreInst(Val, ElemPtr, true, EntryBB->getTerminator());
+ // Call the setjmp instrinsic. It fills in the rest of the jmpbuf
+ Value *SetjmpArg =
+ CastInst::Create(Instruction::BitCast, FieldPtr,
+ Type::getInt8Ty(F.getContext())->getPointerTo(), "",
+ EntryBB->getTerminator());
+ Value *DispatchVal = CallInst::Create(BuiltinSetjmpFn, SetjmpArg,
+ "dispatch",
+ EntryBB->getTerminator());
+ // check the return value of the setjmp. non-zero goes to dispatcher
+ Value *IsNormal = new ICmpInst(EntryBB->getTerminator(),
+ ICmpInst::ICMP_EQ, DispatchVal, Zero,
+ "notunwind");
+ // Nuke the uncond branch.
+ EntryBB->getTerminator()->eraseFromParent();
+
+ // Put in a new condbranch in its place.
+ BranchInst::Create(ContBlock, DispatchBlock, IsNormal, EntryBB);
+
+ // Register the function context and make sure it's known to not throw
+ CallInst *Register =
+ CallInst::Create(RegisterFn, FunctionContext, "",
+ ContBlock->getTerminator());
+ Register->setDoesNotThrow();
+
+ // At this point, we are all set up, update the invoke instructions
+ // to mark their call_site values, and fill in the dispatch switch
+ // accordingly.
+ for (unsigned i = 0, e = Invokes.size(); i != e; ++i)
+ markInvokeCallSite(Invokes[i], i+1, CallSite, DispatchSwitch);
+
+ // The front end has likely added calls to _Unwind_Resume. We need
+ // to find those calls and mark the call_site as -1 immediately prior.
+ // resume is a noreturn function, so any block that has a call to it
+ // should end in an 'unreachable' instruction with the call immediately
+ // prior. That's how we'll search.
+ // ??? There's got to be a better way. this is fugly.
+ for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
+ if ((dyn_cast<UnreachableInst>(BB->getTerminator()))) {
+ BasicBlock::iterator I = BB->getTerminator();
+ // Check the previous instruction and see if it's a resume call
+ if (I == BB->begin()) continue;
+ if (CallInst *CI = dyn_cast<CallInst>(--I)) {
+ if (CI->getCalledFunction() == ResumeFn) {
+ Value *NegativeOne = ConstantInt::get(Int32Ty, -1);
+ new StoreInst(NegativeOne, CallSite, true, I); // volatile
+ }
+ }
+ }
+
+ // Replace all unwinds with a branch to the unwind handler.
+ // ??? Should this ever happen with sjlj exceptions?
+ for (unsigned i = 0, e = Unwinds.size(); i != e; ++i) {
+ BranchInst::Create(UnwindBlock, Unwinds[i]);
+ Unwinds[i]->eraseFromParent();
+ }
+
+ // Finally, for any returns from this function, if this function contains an
+ // invoke, add a call to unregister the function context.
+ for (unsigned i = 0, e = Returns.size(); i != e; ++i)
+ CallInst::Create(UnregisterFn, FunctionContext, "", Returns[i]);
+ }
+
+ return true;
+}
+
+bool SjLjEHPass::runOnFunction(Function &F) {
+ bool Res = insertSjLjEHSupport(F);
+ return Res;
+}
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