diff options
Diffstat (limited to 'lib/CodeGen/SjLjEHPrepare.cpp')
| -rw-r--r-- | lib/CodeGen/SjLjEHPrepare.cpp | 446 |
1 files changed, 228 insertions, 218 deletions
diff --git a/lib/CodeGen/SjLjEHPrepare.cpp b/lib/CodeGen/SjLjEHPrepare.cpp index b637980f885c..13e1454fa5f3 100644 --- a/lib/CodeGen/SjLjEHPrepare.cpp +++ b/lib/CodeGen/SjLjEHPrepare.cpp @@ -21,15 +21,14 @@ #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/ADT/SmallVector.h" -#include "llvm/Support/CommandLine.h" +#include "llvm/ADT/Statistic.h" +#include "llvm/CodeGen/Passes.h" #include "llvm/Support/Debug.h" -#include "llvm/Support/raw_ostream.h" #include "llvm/Target/TargetLowering.h" +#include "llvm/Transforms/Utils/BasicBlockUtils.h" +#include "llvm/Transforms/Utils/Local.h" +#include <set> using namespace llvm; STATISTIC(NumInvokes, "Number of invokes replaced"); @@ -53,6 +52,7 @@ namespace { Constant *SelectorFn; Constant *ExceptionFn; Constant *CallSiteFn; + Constant *DispatchSetupFn; Value *CallSite; public: @@ -116,6 +116,8 @@ bool SjLjEHPass::doInitialization(Module &M) { SelectorFn = Intrinsic::getDeclaration(&M, Intrinsic::eh_selector); ExceptionFn = Intrinsic::getDeclaration(&M, Intrinsic::eh_exception); CallSiteFn = Intrinsic::getDeclaration(&M, Intrinsic::eh_sjlj_callsite); + DispatchSetupFn + = Intrinsic::getDeclaration(&M, Intrinsic::eh_sjlj_dispatch_setup); PersonalityFn = 0; return true; @@ -317,8 +319,12 @@ bool SjLjEHPass::insertSjLjEHSupport(Function &F) { 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 we don't have any invokes, there's nothing to do. + if (Invokes.empty()) return false; // Find the eh.selector.*, eh.exception and alloca calls. // @@ -332,6 +338,7 @@ bool SjLjEHPass::insertSjLjEHSupport(Function &F) { SmallVector<CallInst*,16> EH_Selectors; SmallVector<CallInst*,16> EH_Exceptions; SmallVector<Instruction*,16> JmpbufUpdatePoints; + // Note: Skip the entry block since there's nothing there that interests // us. eh.selector and eh.exception shouldn't ever be there, and we // want to disregard any allocas that are there. @@ -351,228 +358,231 @@ bool SjLjEHPass::insertSjLjEHSupport(Function &F) { } } } + // If we don't have any eh.selector calls, we can't determine the personality // function. Without a personality function, we can't process exceptions. if (!PersonalityFn) return false; - NumInvokes += Invokes.size(); - NumUnwinds += Unwinds.size(); + // 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. + splitLiveRangesAcrossInvokes(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()); + + // 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); + } - 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. - splitLiveRangesAcrossInvokes(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()); - - // 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); - const Type *Ty = Type::getInt8PtrTy(F.getContext()); - Val = CastInst::Create(Instruction::IntToPtr, Val, Ty, "", I); - - I->replaceAllUsesWith(Val); - I->eraseFromParent(); - } + // 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); + const Type *Ty = Type::getInt8PtrTy(F.getContext()); + Val = CastInst::Create(Instruction::IntToPtr, Val, Ty, "", 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 SP, 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", + // 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); + + // Add a call to dispatch_setup at the start of the dispatch block. This is + // expanded to any target-specific setup that needs to be done. + Value *SetupArg = + CastInst::Create(Instruction::BitCast, FunctionContext, + Type::getInt8PtrTy(F.getContext()), "", + DispatchBlock); + CallInst::Create(DispatchSetupFn, SetupArg, "", DispatchBlock); + + // Insert a load of the callsite in the dispatch 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 SP, 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 *JBufPtr + = GetElementPtrInst::Create(FunctionContext, Idxs, Idxs+2, + "jbuf_gep", EntryBB->getTerminator()); - new StoreInst(PersonalityFn, PersonalityFieldPtr, true, - EntryBB->getTerminator()); - - // Save the frame pointer. - Idxs[1] = ConstantInt::get(Int32Ty, 5); - Value *JBufPtr - = GetElementPtrInst::Create(FunctionContext, Idxs, Idxs+2, - "jbuf_gep", - EntryBB->getTerminator()); - Idxs[1] = ConstantInt::get(Int32Ty, 0); - Value *FramePtr = - GetElementPtrInst::Create(JBufPtr, Idxs, Idxs+2, "jbuf_fp_gep", + Idxs[1] = ConstantInt::get(Int32Ty, 0); + Value *FramePtr = + GetElementPtrInst::Create(JBufPtr, Idxs, Idxs+2, "jbuf_fp_gep", + EntryBB->getTerminator()); + + Value *Val = CallInst::Create(FrameAddrFn, + ConstantInt::get(Int32Ty, 0), + "fp", EntryBB->getTerminator()); + new StoreInst(Val, FramePtr, true, EntryBB->getTerminator()); + + // Save the stack pointer. + Idxs[1] = ConstantInt::get(Int32Ty, 2); + Value *StackPtr = + GetElementPtrInst::Create(JBufPtr, Idxs, Idxs+2, "jbuf_sp_gep", + EntryBB->getTerminator()); + + Val = CallInst::Create(StackAddrFn, "sp", EntryBB->getTerminator()); + new StoreInst(Val, StackPtr, true, EntryBB->getTerminator()); + + // Call the setjmp instrinsic. It fills in the rest of the jmpbuf. + Value *SetjmpArg = + CastInst::Create(Instruction::BitCast, JBufPtr, + Type::getInt8PtrTy(F.getContext()), "", + 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); + + // Mark call instructions that aren't nounwind as no-action (call_site == + // -1). Skip the entry block, as prior to then, no function context has been + // created for this function and any unexpected exceptions thrown will go + // directly to the caller's context, which is what we want anyway, so no need + // to do anything here. + for (Function::iterator BB = F.begin(), E = F.end(); ++BB != E;) { + for (BasicBlock::iterator I = BB->begin(), end = BB->end(); I != end; ++I) + if (CallInst *CI = dyn_cast<CallInst>(I)) { + // Ignore calls to the EH builtins (eh.selector, eh.exception) + Constant *Callee = CI->getCalledFunction(); + if (Callee != SelectorFn && Callee != ExceptionFn + && !CI->doesNotThrow()) + insertCallSiteStore(CI, -1, CallSite); + } + } - Value *Val = CallInst::Create(FrameAddrFn, - ConstantInt::get(Int32Ty, 0), - "fp", - EntryBB->getTerminator()); - new StoreInst(Val, FramePtr, true, EntryBB->getTerminator()); - - // Save the stack pointer. - Idxs[1] = ConstantInt::get(Int32Ty, 2); - Value *StackPtr = - GetElementPtrInst::Create(JBufPtr, Idxs, Idxs+2, "jbuf_sp_gep", - EntryBB->getTerminator()); - - Val = CallInst::Create(StackAddrFn, "sp", EntryBB->getTerminator()); - new StoreInst(Val, StackPtr, true, EntryBB->getTerminator()); - - // Call the setjmp instrinsic. It fills in the rest of the jmpbuf. - Value *SetjmpArg = - CastInst::Create(Instruction::BitCast, JBufPtr, - Type::getInt8PtrTy(F.getContext()), "", - 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); - - // Mark call instructions that aren't nounwind as no-action - // (call_site == -1). Skip the entry block, as prior to then, no function - // context has been created for this function and any unexpected exceptions - // thrown will go directly to the caller's context, which is what we want - // anyway, so no need to do anything here. - for (Function::iterator BB = F.begin(), E = F.end(); ++BB != E;) { - for (BasicBlock::iterator I = BB->begin(), end = BB->end(); I != end; ++I) - if (CallInst *CI = dyn_cast<CallInst>(I)) { - // Ignore calls to the EH builtins (eh.selector, eh.exception) - Constant *Callee = CI->getCalledFunction(); - if (Callee != SelectorFn && Callee != ExceptionFn - && !CI->doesNotThrow()) - insertCallSiteStore(CI, -1, CallSite); - } - } - - // 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(); - } - - // Following any allocas not in the entry block, update the saved SP - // in the jmpbuf to the new value. - for (unsigned i = 0, e = JmpbufUpdatePoints.size(); i != e; ++i) { - Instruction *AI = JmpbufUpdatePoints[i]; - Instruction *StackAddr = CallInst::Create(StackAddrFn, "sp"); - StackAddr->insertAfter(AI); - Instruction *StoreStackAddr = new StoreInst(StackAddr, StackPtr, true); - StoreStackAddr->insertAfter(StackAddr); - } + // 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]); + // Following any allocas not in the entry block, update the saved SP in the + // jmpbuf to the new value. + for (unsigned i = 0, e = JmpbufUpdatePoints.size(); i != e; ++i) { + Instruction *AI = JmpbufUpdatePoints[i]; + Instruction *StackAddr = CallInst::Create(StackAddrFn, "sp"); + StackAddr->insertAfter(AI); + Instruction *StoreStackAddr = new StoreInst(StackAddr, StackPtr, true); + StoreStackAddr->insertAfter(StackAddr); } + // 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; } |