mirror of
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synced 2024-08-24 09:29:42 +00:00
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. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@79250 91177308-0d34-0410-b5e6-96231b3b80d8
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@ -193,6 +193,10 @@ namespace llvm {
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/// adapted to code generation. Required if using dwarf exception handling.
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FunctionPass *createDwarfEHPass(const TargetLowering *tli, bool fast);
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/// createSjLjEHPass - This pass adapts exception handling code to use
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/// the GCC-style builtin setjmp/longjmp (sjlj) to handling EH control flow.
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FunctionPass *createSjLjEHPass(const TargetLowering *tli);
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} // End llvm namespace
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#endif
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@ -364,7 +364,6 @@ ComputeActionsTable(const SmallVectorImpl<const LandingPadInfo*> &LandingPads,
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/// try-range address.
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void DwarfException::
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ComputeCallSiteTable(SmallVectorImpl<CallSiteEntry> &CallSites,
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std::map<unsigned,CallSiteEntry*> &CallSiteIndexMap,
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const RangeMapType &PadMap,
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const SmallVectorImpl<const LandingPadInfo *> &LandingPads,
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const SmallVectorImpl<unsigned> &FirstActions) {
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@ -438,12 +437,6 @@ ComputeCallSiteTable(SmallVectorImpl<CallSiteEntry> &CallSites,
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// Otherwise, create a new call-site.
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CallSites.push_back(Site);
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// For SjLj handling, map the call site entry to its index
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if (TAI->getExceptionHandlingType() == ExceptionHandling::SjLj) {
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unsigned Index =
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MF->getLandingPadCallSiteIndex(LandingPad->LandingPadBlock);
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CallSiteIndexMap[Index] = &CallSites.back();
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}
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PreviousIsInvoke = true;
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} else {
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// Create a gap.
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@ -520,9 +513,7 @@ void DwarfException::EmitExceptionTable() {
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// Compute the call-site table.
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SmallVector<CallSiteEntry, 64> CallSites;
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std::map<unsigned,CallSiteEntry*> CallSiteIndexMap;
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ComputeCallSiteTable(CallSites, CallSiteIndexMap, PadMap,
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LandingPads, FirstActions);
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ComputeCallSiteTable(CallSites, PadMap, LandingPads, FirstActions);
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// Final tallies.
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@ -537,8 +528,7 @@ void DwarfException::EmitExceptionTable() {
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if (TAI->getExceptionHandlingType() == ExceptionHandling::SjLj) {
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SizeSites = (MF->getMaxCallSiteIndex() - CallSites.size()) *
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TargetAsmInfo::getULEB128Size(0) * 2;
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SizeSites = 0;
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} else
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SizeSites = CallSites.size() *
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(SiteStartSize + SiteLengthSize + LandingPadSize);
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@ -546,7 +536,6 @@ void DwarfException::EmitExceptionTable() {
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SizeSites += TargetAsmInfo::getULEB128Size(CallSites[i].Action);
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if (TAI->getExceptionHandlingType() == ExceptionHandling::SjLj)
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SizeSites += TargetAsmInfo::getULEB128Size(i);
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// FIXME: 'i' above should be the landing pad index
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}
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// Type infos.
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const unsigned TypeInfoSize = TD->getPointerSize(); // DW_EH_PE_absptr
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@ -655,25 +644,11 @@ void DwarfException::EmitExceptionTable() {
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assert(MF->getCallSiteCount() == CallSites.size());
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// Emit the landing pad site information.
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// SjLj handling assigned the call site indices in the front end, so
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// we need to make sure the table here lines up with that. That's pretty
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// horrible, and should be fixed ASAP to do that stuff in the back end
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// instead.
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std::map<unsigned, CallSiteEntry*>::const_iterator I, E;
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I = CallSiteIndexMap.begin();
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E = CallSiteIndexMap.end();
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for (unsigned CurrIdx = 1; I != E; ++I) {
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// paranoia.
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assert(CurrIdx <= I->first);
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// Fill in any gaps in the table
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while (CurrIdx++ < I->first) {
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Asm->EmitULEB128Bytes(0);
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Asm->EOL("Filler landing pad");
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Asm->EmitULEB128Bytes(0);
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Asm->EOL("Filler action");
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}
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const CallSiteEntry &S = *(I->second);
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Asm->EmitULEB128Bytes(I->first - 1);
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unsigned idx = 0;
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for (SmallVectorImpl<CallSiteEntry>::const_iterator
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I = CallSites.begin(), E = CallSites.end(); I != E; ++I, ++idx) {
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const CallSiteEntry &S = *I;
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Asm->EmitULEB128Bytes(idx);
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Asm->EOL("Landing pad");
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Asm->EmitULEB128Bytes(S.Action);
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Asm->EOL("Action");
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@ -155,7 +155,6 @@ class VISIBILITY_HIDDEN DwarfException : public Dwarf {
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/// of any entry - they form gaps in the table. Entries must be ordered by
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/// try-range address.
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void ComputeCallSiteTable(SmallVectorImpl<CallSiteEntry> &CallSites,
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std::map<unsigned,CallSiteEntry*> &CallSiteIndexMap,
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const RangeMapType &PadMap,
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const SmallVectorImpl<const LandingPadInfo *> &LPs,
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const SmallVectorImpl<unsigned> &FirstActions);
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@ -241,8 +241,11 @@ bool LLVMTargetMachine::addCommonCodeGenPasses(PassManagerBase &PM,
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// handle.
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switch (getTargetAsmInfo()->getExceptionHandlingType())
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{
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// SjLj piggy-backs on dwarf for this bit
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case ExceptionHandling::SjLj:
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// SjLj piggy-backs on dwarf for this bit. The cleanups done apply to both
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PM.add(createDwarfEHPass(getTargetLowering(), OptLevel==CodeGenOpt::None));
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PM.add(createSjLjEHPass(getTargetLowering()));
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break;
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case ExceptionHandling::Dwarf:
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PM.add(createDwarfEHPass(getTargetLowering(), OptLevel==CodeGenOpt::None));
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break;
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527
lib/CodeGen/SjLjEHPrepare.cpp
Normal file
527
lib/CodeGen/SjLjEHPrepare.cpp
Normal file
@ -0,0 +1,527 @@
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//===- SjLjEHPass.cpp - Eliminate Invoke & Unwind instructions -----------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This transformation is designed for use by code generators which use SjLj
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// based exception handling.
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//
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//===----------------------------------------------------------------------===//
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#define DEBUG_TYPE "sjljehprepare"
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#include "llvm/Transforms/Scalar.h"
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#include "llvm/Constants.h"
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#include "llvm/DerivedTypes.h"
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#include "llvm/Instructions.h"
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#include "llvm/Intrinsics.h"
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#include "llvm/LLVMContext.h"
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#include "llvm/Module.h"
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#include "llvm/Pass.h"
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#include "llvm/CodeGen/Passes.h"
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#include "llvm/Transforms/Utils/BasicBlockUtils.h"
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#include "llvm/Transforms/Utils/Local.h"
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#include "llvm/ADT/Statistic.h"
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#include "llvm/Support/CommandLine.h"
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#include "llvm/Support/Compiler.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/raw_ostream.h"
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#include "llvm/Target/TargetLowering.h"
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#include <set>
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using namespace llvm;
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STATISTIC(NumInvokes, "Number of invokes replaced");
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STATISTIC(NumUnwinds, "Number of unwinds replaced");
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STATISTIC(NumSpilled, "Number of registers live across unwind edges");
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namespace {
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class VISIBILITY_HIDDEN SjLjEHPass : public FunctionPass {
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const TargetLowering *TLI;
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const Type *FunctionContextTy;
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Constant *RegisterFn;
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Constant *UnregisterFn;
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Constant *ResumeFn;
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Constant *BuiltinSetjmpFn;
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Constant *FrameAddrFn;
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Constant *LSDAAddrFn;
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Value *PersonalityFn;
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Constant *Selector32Fn;
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Constant *Selector64Fn;
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Constant *ExceptionFn;
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Value *CallSite;
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public:
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static char ID; // Pass identification, replacement for typeid
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explicit SjLjEHPass(const TargetLowering *tli = NULL)
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: FunctionPass(&ID), TLI(tli) { }
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bool doInitialization(Module &M);
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bool runOnFunction(Function &F);
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virtual void getAnalysisUsage(AnalysisUsage &AU) const { }
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const char *getPassName() const {
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return "SJLJ Exception Handling preparation";
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}
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private:
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void markInvokeCallSite(InvokeInst *II, unsigned InvokeNo,
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Value *CallSite,
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SwitchInst *CatchSwitch);
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void splitLiveRangesLiveAcrossInvokes(std::vector<InvokeInst*> &Invokes);
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bool insertSjLjEHSupport(Function &F);
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};
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} // end anonymous namespace
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char SjLjEHPass::ID = 0;
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// Public Interface To the SjLjEHPass pass.
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FunctionPass *llvm::createSjLjEHPass(const TargetLowering *TLI) {
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return new SjLjEHPass(TLI);
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}
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// doInitialization - Make sure that there is a prototype for abort in the
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// current module.
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bool SjLjEHPass::doInitialization(Module &M) {
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// Build the function context structure.
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// builtin_setjmp uses a five word jbuf
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const Type *VoidPtrTy =
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PointerType::getUnqual(Type::getInt8Ty(M.getContext()));
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const Type *Int32Ty = Type::getInt32Ty(M.getContext());
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FunctionContextTy =
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StructType::get(M.getContext(),
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VoidPtrTy, // __prev
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Int32Ty, // call_site
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ArrayType::get(Int32Ty, 4), // __data
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VoidPtrTy, // __personality
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VoidPtrTy, // __lsda
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ArrayType::get(VoidPtrTy, 5), // __jbuf
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NULL);
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RegisterFn = M.getOrInsertFunction("_Unwind_SjLj_Register",
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Type::getVoidTy(M.getContext()),
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PointerType::getUnqual(FunctionContextTy),
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(Type *)0);
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UnregisterFn =
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M.getOrInsertFunction("_Unwind_SjLj_Unregister",
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Type::getVoidTy(M.getContext()),
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PointerType::getUnqual(FunctionContextTy),
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(Type *)0);
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ResumeFn =
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M.getOrInsertFunction("_Unwind_SjLj_Resume",
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Type::getVoidTy(M.getContext()),
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VoidPtrTy,
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(Type *)0);
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FrameAddrFn = Intrinsic::getDeclaration(&M, Intrinsic::frameaddress);
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BuiltinSetjmpFn = Intrinsic::getDeclaration(&M, Intrinsic::eh_sjlj_setjmp);
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LSDAAddrFn = Intrinsic::getDeclaration(&M, Intrinsic::eh_sjlj_lsda);
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Selector32Fn = Intrinsic::getDeclaration(&M, Intrinsic::eh_selector_i32);
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Selector64Fn = Intrinsic::getDeclaration(&M, Intrinsic::eh_selector_i64);
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ExceptionFn = Intrinsic::getDeclaration(&M, Intrinsic::eh_exception);
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return true;
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}
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/// markInvokeCallSite - Insert code to mark the call_site for this invoke
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void SjLjEHPass::markInvokeCallSite(InvokeInst *II, unsigned InvokeNo,
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Value *CallSite,
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SwitchInst *CatchSwitch) {
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ConstantInt *CallSiteNoC= ConstantInt::get(Type::getInt32Ty(II->getContext()),
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InvokeNo);
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// The runtime comes back to the dispatcher with the call_site - 1 in
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// the context. Odd, but there it is.
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ConstantInt *SwitchValC = ConstantInt::get(Type::getInt32Ty(II->getContext()),
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InvokeNo - 1);
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// If the unwind edge has phi nodes, split the edge.
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if (isa<PHINode>(II->getUnwindDest()->begin())) {
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SplitCriticalEdge(II, 1, this);
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// If there are any phi nodes left, they must have a single predecessor.
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while (PHINode *PN = dyn_cast<PHINode>(II->getUnwindDest()->begin())) {
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PN->replaceAllUsesWith(PN->getIncomingValue(0));
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PN->eraseFromParent();
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}
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}
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// Insert a store of the invoke num before the invoke and store zero into the
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// location afterward.
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new StoreInst(CallSiteNoC, CallSite, true, II); // volatile
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// Add a switch case to our unwind block.
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CatchSwitch->addCase(SwitchValC, II->getUnwindDest());
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// We still want this to look like an invoke so we emit the LSDA properly
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// FIXME: ??? Or will this cause strangeness with mis-matched IDs like
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// when it was in the front end?
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}
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/// MarkBlocksLiveIn - Insert BB and all of its predescessors into LiveBBs until
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/// we reach blocks we've already seen.
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static void MarkBlocksLiveIn(BasicBlock *BB, std::set<BasicBlock*> &LiveBBs) {
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if (!LiveBBs.insert(BB).second) return; // already been here.
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for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI)
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MarkBlocksLiveIn(*PI, LiveBBs);
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}
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// live across unwind edges. Each value that is live across an unwind edge
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// we spill into a stack location, guaranteeing that there is nothing live
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// across the unwind edge. This process also splits all critical edges
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// coming out of invoke's.
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void SjLjEHPass::
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splitLiveRangesLiveAcrossInvokes(std::vector<InvokeInst*> &Invokes) {
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// First step, split all critical edges from invoke instructions.
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for (unsigned i = 0, e = Invokes.size(); i != e; ++i) {
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InvokeInst *II = Invokes[i];
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SplitCriticalEdge(II, 0, this);
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SplitCriticalEdge(II, 1, this);
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assert(!isa<PHINode>(II->getNormalDest()) &&
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!isa<PHINode>(II->getUnwindDest()) &&
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"critical edge splitting left single entry phi nodes?");
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}
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Function *F = Invokes.back()->getParent()->getParent();
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// To avoid having to handle incoming arguments specially, we lower each arg
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// to a copy instruction in the entry block. This ensures that the argument
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// value itself cannot be live across the entry block.
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BasicBlock::iterator AfterAllocaInsertPt = F->begin()->begin();
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while (isa<AllocaInst>(AfterAllocaInsertPt) &&
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isa<ConstantInt>(cast<AllocaInst>(AfterAllocaInsertPt)->getArraySize()))
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++AfterAllocaInsertPt;
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for (Function::arg_iterator AI = F->arg_begin(), E = F->arg_end();
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AI != E; ++AI) {
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// This is always a no-op cast because we're casting AI to AI->getType() so
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// src and destination types are identical. BitCast is the only possibility.
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CastInst *NC = new BitCastInst(
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AI, AI->getType(), AI->getName()+".tmp", AfterAllocaInsertPt);
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AI->replaceAllUsesWith(NC);
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// Normally its is forbidden to replace a CastInst's operand because it
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// could cause the opcode to reflect an illegal conversion. However, we're
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// replacing it here with the same value it was constructed with to simply
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// make NC its user.
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NC->setOperand(0, AI);
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}
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// Finally, scan the code looking for instructions with bad live ranges.
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for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
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for (BasicBlock::iterator II = BB->begin(), E = BB->end(); II != E; ++II) {
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// Ignore obvious cases we don't have to handle. In particular, most
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// instructions either have no uses or only have a single use inside the
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// current block. Ignore them quickly.
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Instruction *Inst = II;
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if (Inst->use_empty()) continue;
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if (Inst->hasOneUse() &&
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cast<Instruction>(Inst->use_back())->getParent() == BB &&
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!isa<PHINode>(Inst->use_back())) continue;
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// If this is an alloca in the entry block, it's not a real register
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// value.
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if (AllocaInst *AI = dyn_cast<AllocaInst>(Inst))
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if (isa<ConstantInt>(AI->getArraySize()) && BB == F->begin())
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continue;
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// Avoid iterator invalidation by copying users to a temporary vector.
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std::vector<Instruction*> Users;
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for (Value::use_iterator UI = Inst->use_begin(), E = Inst->use_end();
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UI != E; ++UI) {
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Instruction *User = cast<Instruction>(*UI);
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if (User->getParent() != BB || isa<PHINode>(User))
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Users.push_back(User);
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}
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// Scan all of the uses and see if the live range is live across an unwind
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// edge. If we find a use live across an invoke edge, create an alloca
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// and spill the value.
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std::set<InvokeInst*> InvokesWithStoreInserted;
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// Find all of the blocks that this value is live in.
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std::set<BasicBlock*> LiveBBs;
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LiveBBs.insert(Inst->getParent());
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while (!Users.empty()) {
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Instruction *U = Users.back();
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Users.pop_back();
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if (!isa<PHINode>(U)) {
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MarkBlocksLiveIn(U->getParent(), LiveBBs);
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} else {
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// Uses for a PHI node occur in their predecessor block.
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PHINode *PN = cast<PHINode>(U);
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for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
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if (PN->getIncomingValue(i) == Inst)
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MarkBlocksLiveIn(PN->getIncomingBlock(i), LiveBBs);
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}
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}
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// Now that we know all of the blocks that this thing is live in, see if
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// it includes any of the unwind locations.
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bool NeedsSpill = false;
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for (unsigned i = 0, e = Invokes.size(); i != e; ++i) {
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BasicBlock *UnwindBlock = Invokes[i]->getUnwindDest();
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if (UnwindBlock != BB && LiveBBs.count(UnwindBlock)) {
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NeedsSpill = true;
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}
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}
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// If we decided we need a spill, do it.
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if (NeedsSpill) {
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++NumSpilled;
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DemoteRegToStack(*Inst, true);
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}
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}
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}
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bool SjLjEHPass::insertSjLjEHSupport(Function &F) {
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std::vector<ReturnInst*> Returns;
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std::vector<UnwindInst*> Unwinds;
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std::vector<InvokeInst*> Invokes;
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// Look through the terminators of the basic blocks to find invokes, returns
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// and unwinds
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for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
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if (ReturnInst *RI = dyn_cast<ReturnInst>(BB->getTerminator())) {
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// Remember all return instructions in case we insert an invoke into this
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// function.
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Returns.push_back(RI);
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} else if (InvokeInst *II = dyn_cast<InvokeInst>(BB->getTerminator())) {
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Invokes.push_back(II);
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} else if (UnwindInst *UI = dyn_cast<UnwindInst>(BB->getTerminator())) {
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Unwinds.push_back(UI);
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||||
}
|
||||
// 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;
|
||||
}
|
Loading…
Reference in New Issue
Block a user