Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 1 | //===- LowerSetJmp.cpp - Code pertaining to lowering set/long jumps -------===// |
Misha Brukman | fd93908 | 2005-04-21 23:48:37 +0000 | [diff] [blame] | 2 | // |
John Criswell | b576c94 | 2003-10-20 19:43:21 +0000 | [diff] [blame] | 3 | // The LLVM Compiler Infrastructure |
| 4 | // |
Chris Lattner | 4ee451d | 2007-12-29 20:36:04 +0000 | [diff] [blame] | 5 | // This file is distributed under the University of Illinois Open Source |
| 6 | // License. See LICENSE.TXT for details. |
Misha Brukman | fd93908 | 2005-04-21 23:48:37 +0000 | [diff] [blame] | 7 | // |
John Criswell | b576c94 | 2003-10-20 19:43:21 +0000 | [diff] [blame] | 8 | //===----------------------------------------------------------------------===// |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 9 | // |
| 10 | // This file implements the lowering of setjmp and longjmp to use the |
Chris Lattner | 77b398c | 2003-09-15 05:43:05 +0000 | [diff] [blame] | 11 | // LLVM invoke and unwind instructions as necessary. |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 12 | // |
| 13 | // Lowering of longjmp is fairly trivial. We replace the call with a |
| 14 | // call to the LLVM library function "__llvm_sjljeh_throw_longjmp()". |
| 15 | // This unwinds the stack for us calling all of the destructors for |
| 16 | // objects allocated on the stack. |
| 17 | // |
| 18 | // At a setjmp call, the basic block is split and the setjmp removed. |
| 19 | // The calls in a function that have a setjmp are converted to invoke |
| 20 | // where the except part checks to see if it's a longjmp exception and, |
| 21 | // if so, if it's handled in the function. If it is, then it gets the |
| 22 | // value returned by the longjmp and goes to where the basic block was |
| 23 | // split. Invoke instructions are handled in a similar fashion with the |
| 24 | // original except block being executed if it isn't a longjmp except |
| 25 | // that is handled by that function. |
| 26 | // |
| 27 | //===----------------------------------------------------------------------===// |
| 28 | |
| 29 | //===----------------------------------------------------------------------===// |
| 30 | // FIXME: This pass doesn't deal with PHI statements just yet. That is, |
| 31 | // we expect this to occur before SSAification is done. This would seem |
| 32 | // to make sense, but in general, it might be a good idea to make this |
| 33 | // pass invokable via the "opt" command at will. |
| 34 | //===----------------------------------------------------------------------===// |
| 35 | |
Chris Lattner | 86453c5 | 2006-12-19 22:09:18 +0000 | [diff] [blame] | 36 | #define DEBUG_TYPE "lowersetjmp" |
Chris Lattner | 1e2385b | 2003-11-21 21:54:22 +0000 | [diff] [blame] | 37 | #include "llvm/Transforms/IPO.h" |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 38 | #include "llvm/Constants.h" |
| 39 | #include "llvm/DerivedTypes.h" |
| 40 | #include "llvm/Instructions.h" |
| 41 | #include "llvm/Intrinsics.h" |
| 42 | #include "llvm/Module.h" |
| 43 | #include "llvm/Pass.h" |
Chris Lattner | bb2d4de | 2003-10-13 00:57:16 +0000 | [diff] [blame] | 44 | #include "llvm/Support/CFG.h" |
Reid Spencer | 9133fe2 | 2007-02-05 23:32:05 +0000 | [diff] [blame] | 45 | #include "llvm/Support/Compiler.h" |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 46 | #include "llvm/Support/InstVisitor.h" |
Chris Lattner | a2dc727 | 2004-03-14 02:13:38 +0000 | [diff] [blame] | 47 | #include "llvm/Transforms/Utils/Local.h" |
Reid Spencer | 551ccae | 2004-09-01 22:55:40 +0000 | [diff] [blame] | 48 | #include "llvm/ADT/DepthFirstIterator.h" |
| 49 | #include "llvm/ADT/Statistic.h" |
| 50 | #include "llvm/ADT/StringExtras.h" |
| 51 | #include "llvm/ADT/VectorExtras.h" |
David Greene | 52eec54 | 2007-08-01 03:43:44 +0000 | [diff] [blame] | 52 | #include "llvm/ADT/SmallVector.h" |
Dan Gohman | c9235d2 | 2008-03-21 23:51:57 +0000 | [diff] [blame] | 53 | #include <map> |
Chris Lattner | 1e2385b | 2003-11-21 21:54:22 +0000 | [diff] [blame] | 54 | using namespace llvm; |
Brian Gaeke | d0fde30 | 2003-11-11 22:41:34 +0000 | [diff] [blame] | 55 | |
Chris Lattner | 86453c5 | 2006-12-19 22:09:18 +0000 | [diff] [blame] | 56 | STATISTIC(LongJmpsTransformed, "Number of longjmps transformed"); |
| 57 | STATISTIC(SetJmpsTransformed , "Number of setjmps transformed"); |
| 58 | STATISTIC(CallsTransformed , "Number of calls invokified"); |
| 59 | STATISTIC(InvokesTransformed , "Number of invokes modified"); |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 60 | |
Chris Lattner | 86453c5 | 2006-12-19 22:09:18 +0000 | [diff] [blame] | 61 | namespace { |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 62 | //===--------------------------------------------------------------------===// |
Chris Lattner | bc53e5e | 2004-10-07 06:00:24 +0000 | [diff] [blame] | 63 | // LowerSetJmp pass implementation. |
Reid Spencer | 9133fe2 | 2007-02-05 23:32:05 +0000 | [diff] [blame] | 64 | class VISIBILITY_HIDDEN LowerSetJmp : public ModulePass, |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 65 | public InstVisitor<LowerSetJmp> { |
| 66 | // LLVM library functions... |
Chris Lattner | 35057c2 | 2007-01-07 06:59:47 +0000 | [diff] [blame] | 67 | Constant *InitSJMap; // __llvm_sjljeh_init_setjmpmap |
| 68 | Constant *DestroySJMap; // __llvm_sjljeh_destroy_setjmpmap |
| 69 | Constant *AddSJToMap; // __llvm_sjljeh_add_setjmp_to_map |
| 70 | Constant *ThrowLongJmp; // __llvm_sjljeh_throw_longjmp |
| 71 | Constant *TryCatchLJ; // __llvm_sjljeh_try_catching_longjmp_exception |
| 72 | Constant *IsLJException; // __llvm_sjljeh_is_longjmp_exception |
| 73 | Constant *GetLJValue; // __llvm_sjljeh_get_longjmp_value |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 74 | |
| 75 | typedef std::pair<SwitchInst*, CallInst*> SwitchValuePair; |
| 76 | |
Chris Lattner | bb2d4de | 2003-10-13 00:57:16 +0000 | [diff] [blame] | 77 | // Keep track of those basic blocks reachable via a depth-first search of |
| 78 | // the CFG from a setjmp call. We only need to transform those "call" and |
| 79 | // "invoke" instructions that are reachable from the setjmp call site. |
| 80 | std::set<BasicBlock*> DFSBlocks; |
| 81 | |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 82 | // The setjmp map is going to hold information about which setjmps |
| 83 | // were called (each setjmp gets its own number) and with which |
| 84 | // buffer it was called. |
| 85 | std::map<Function*, AllocaInst*> SJMap; |
| 86 | |
| 87 | // The rethrow basic block map holds the basic block to branch to if |
| 88 | // the exception isn't handled in the current function and needs to |
| 89 | // be rethrown. |
| 90 | std::map<const Function*, BasicBlock*> RethrowBBMap; |
| 91 | |
| 92 | // The preliminary basic block map holds a basic block that grabs the |
| 93 | // exception and determines if it's handled by the current function. |
| 94 | std::map<const Function*, BasicBlock*> PrelimBBMap; |
| 95 | |
| 96 | // The switch/value map holds a switch inst/call inst pair. The |
| 97 | // switch inst controls which handler (if any) gets called and the |
| 98 | // value is the value returned to that handler by the call to |
| 99 | // __llvm_sjljeh_get_longjmp_value. |
| 100 | std::map<const Function*, SwitchValuePair> SwitchValMap; |
| 101 | |
| 102 | // A map of which setjmps we've seen so far in a function. |
| 103 | std::map<const Function*, unsigned> SetJmpIDMap; |
| 104 | |
| 105 | AllocaInst* GetSetJmpMap(Function* Func); |
| 106 | BasicBlock* GetRethrowBB(Function* Func); |
| 107 | SwitchValuePair GetSJSwitch(Function* Func, BasicBlock* Rethrow); |
| 108 | |
| 109 | void TransformLongJmpCall(CallInst* Inst); |
| 110 | void TransformSetJmpCall(CallInst* Inst); |
| 111 | |
| 112 | bool IsTransformableFunction(const std::string& Name); |
| 113 | public: |
Nick Lewycky | ecd94c8 | 2007-05-06 13:37:16 +0000 | [diff] [blame] | 114 | static char ID; // Pass identification, replacement for typeid |
Devang Patel | 794fd75 | 2007-05-01 21:15:47 +0000 | [diff] [blame] | 115 | LowerSetJmp() : ModulePass((intptr_t)&ID) {} |
| 116 | |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 117 | void visitCallInst(CallInst& CI); |
| 118 | void visitInvokeInst(InvokeInst& II); |
| 119 | void visitReturnInst(ReturnInst& RI); |
| 120 | void visitUnwindInst(UnwindInst& UI); |
| 121 | |
Chris Lattner | b12914b | 2004-09-20 04:48:05 +0000 | [diff] [blame] | 122 | bool runOnModule(Module& M); |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 123 | bool doInitialization(Module& M); |
| 124 | }; |
| 125 | |
Devang Patel | 1997473 | 2007-05-03 01:11:54 +0000 | [diff] [blame] | 126 | char LowerSetJmp::ID = 0; |
Chris Lattner | 7f8897f | 2006-08-27 22:42:52 +0000 | [diff] [blame] | 127 | RegisterPass<LowerSetJmp> X("lowersetjmp", "Lower Set Jump"); |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 128 | } // end anonymous namespace |
| 129 | |
| 130 | // run - Run the transformation on the program. We grab the function |
| 131 | // prototypes for longjmp and setjmp. If they are used in the program, |
| 132 | // then we can go directly to the places they're at and transform them. |
Chris Lattner | b12914b | 2004-09-20 04:48:05 +0000 | [diff] [blame] | 133 | bool LowerSetJmp::runOnModule(Module& M) { |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 134 | bool Changed = false; |
| 135 | |
| 136 | // These are what the functions are called. |
Reid Spencer | 688b049 | 2007-02-05 21:19:13 +0000 | [diff] [blame] | 137 | Function* SetJmp = M.getFunction("llvm.setjmp"); |
| 138 | Function* LongJmp = M.getFunction("llvm.longjmp"); |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 139 | |
| 140 | // This program doesn't have longjmp and setjmp calls. |
| 141 | if ((!LongJmp || LongJmp->use_empty()) && |
| 142 | (!SetJmp || SetJmp->use_empty())) return false; |
| 143 | |
| 144 | // Initialize some values and functions we'll need to transform the |
| 145 | // setjmp/longjmp functions. |
| 146 | doInitialization(M); |
| 147 | |
Chris Lattner | bb2d4de | 2003-10-13 00:57:16 +0000 | [diff] [blame] | 148 | if (SetJmp) { |
Chris Lattner | bb2d4de | 2003-10-13 00:57:16 +0000 | [diff] [blame] | 149 | for (Value::use_iterator B = SetJmp->use_begin(), E = SetJmp->use_end(); |
| 150 | B != E; ++B) { |
Chris Lattner | 6d3906b | 2003-10-13 01:02:33 +0000 | [diff] [blame] | 151 | BasicBlock* BB = cast<Instruction>(*B)->getParent(); |
Chris Lattner | 8b716f6 | 2003-10-13 16:49:21 +0000 | [diff] [blame] | 152 | for (df_ext_iterator<BasicBlock*> I = df_ext_begin(BB, DFSBlocks), |
| 153 | E = df_ext_end(BB, DFSBlocks); I != E; ++I) |
Chris Lattner | 46e033d | 2003-10-13 16:44:50 +0000 | [diff] [blame] | 154 | /* empty */; |
Chris Lattner | bb2d4de | 2003-10-13 00:57:16 +0000 | [diff] [blame] | 155 | } |
| 156 | |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 157 | while (!SetJmp->use_empty()) { |
| 158 | assert(isa<CallInst>(SetJmp->use_back()) && |
| 159 | "User of setjmp intrinsic not a call?"); |
| 160 | TransformSetJmpCall(cast<CallInst>(SetJmp->use_back())); |
| 161 | Changed = true; |
| 162 | } |
Chris Lattner | bb2d4de | 2003-10-13 00:57:16 +0000 | [diff] [blame] | 163 | } |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 164 | |
| 165 | if (LongJmp) |
| 166 | while (!LongJmp->use_empty()) { |
| 167 | assert(isa<CallInst>(LongJmp->use_back()) && |
| 168 | "User of longjmp intrinsic not a call?"); |
| 169 | TransformLongJmpCall(cast<CallInst>(LongJmp->use_back())); |
| 170 | Changed = true; |
| 171 | } |
| 172 | |
| 173 | // Now go through the affected functions and convert calls and invokes |
| 174 | // to new invokes... |
| 175 | for (std::map<Function*, AllocaInst*>::iterator |
| 176 | B = SJMap.begin(), E = SJMap.end(); B != E; ++B) { |
| 177 | Function* F = B->first; |
| 178 | for (Function::iterator BB = F->begin(), BE = F->end(); BB != BE; ++BB) |
| 179 | for (BasicBlock::iterator IB = BB->begin(), IE = BB->end(); IB != IE; ) { |
| 180 | visit(*IB++); |
| 181 | if (IB != BB->end() && IB->getParent() != BB) |
| 182 | break; // The next instruction got moved to a different block! |
| 183 | } |
| 184 | } |
| 185 | |
Chris Lattner | bb2d4de | 2003-10-13 00:57:16 +0000 | [diff] [blame] | 186 | DFSBlocks.clear(); |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 187 | SJMap.clear(); |
| 188 | RethrowBBMap.clear(); |
| 189 | PrelimBBMap.clear(); |
| 190 | SwitchValMap.clear(); |
| 191 | SetJmpIDMap.clear(); |
| 192 | |
| 193 | return Changed; |
| 194 | } |
| 195 | |
| 196 | // doInitialization - For the lower long/setjmp pass, this ensures that a |
| 197 | // module contains a declaration for the intrisic functions we are going |
| 198 | // to call to convert longjmp and setjmp calls. |
| 199 | // |
| 200 | // This function is always successful, unless it isn't. |
| 201 | bool LowerSetJmp::doInitialization(Module& M) |
| 202 | { |
Christopher Lamb | 43ad6b3 | 2007-12-17 01:12:55 +0000 | [diff] [blame] | 203 | const Type *SBPTy = PointerType::getUnqual(Type::Int8Ty); |
| 204 | const Type *SBPPTy = PointerType::getUnqual(SBPTy); |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 205 | |
| 206 | // N.B. See llvm/runtime/GCCLibraries/libexception/SJLJ-Exception.h for |
| 207 | // a description of the following library functions. |
| 208 | |
| 209 | // void __llvm_sjljeh_init_setjmpmap(void**) |
| 210 | InitSJMap = M.getOrInsertFunction("__llvm_sjljeh_init_setjmpmap", |
Jeff Cohen | 66c5fd6 | 2005-10-23 04:37:20 +0000 | [diff] [blame] | 211 | Type::VoidTy, SBPPTy, (Type *)0); |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 212 | // void __llvm_sjljeh_destroy_setjmpmap(void**) |
| 213 | DestroySJMap = M.getOrInsertFunction("__llvm_sjljeh_destroy_setjmpmap", |
Jeff Cohen | 66c5fd6 | 2005-10-23 04:37:20 +0000 | [diff] [blame] | 214 | Type::VoidTy, SBPPTy, (Type *)0); |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 215 | |
| 216 | // void __llvm_sjljeh_add_setjmp_to_map(void**, void*, unsigned) |
| 217 | AddSJToMap = M.getOrInsertFunction("__llvm_sjljeh_add_setjmp_to_map", |
| 218 | Type::VoidTy, SBPPTy, SBPTy, |
Reid Spencer | c5b206b | 2006-12-31 05:48:39 +0000 | [diff] [blame] | 219 | Type::Int32Ty, (Type *)0); |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 220 | |
| 221 | // void __llvm_sjljeh_throw_longjmp(int*, int) |
| 222 | ThrowLongJmp = M.getOrInsertFunction("__llvm_sjljeh_throw_longjmp", |
Reid Spencer | c5b206b | 2006-12-31 05:48:39 +0000 | [diff] [blame] | 223 | Type::VoidTy, SBPTy, Type::Int32Ty, |
Jeff Cohen | 66c5fd6 | 2005-10-23 04:37:20 +0000 | [diff] [blame] | 224 | (Type *)0); |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 225 | |
| 226 | // unsigned __llvm_sjljeh_try_catching_longjmp_exception(void **) |
| 227 | TryCatchLJ = |
| 228 | M.getOrInsertFunction("__llvm_sjljeh_try_catching_longjmp_exception", |
Reid Spencer | c5b206b | 2006-12-31 05:48:39 +0000 | [diff] [blame] | 229 | Type::Int32Ty, SBPPTy, (Type *)0); |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 230 | |
| 231 | // bool __llvm_sjljeh_is_longjmp_exception() |
| 232 | IsLJException = M.getOrInsertFunction("__llvm_sjljeh_is_longjmp_exception", |
Reid Spencer | 4fe16d6 | 2007-01-11 18:21:29 +0000 | [diff] [blame] | 233 | Type::Int1Ty, (Type *)0); |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 234 | |
| 235 | // int __llvm_sjljeh_get_longjmp_value() |
| 236 | GetLJValue = M.getOrInsertFunction("__llvm_sjljeh_get_longjmp_value", |
Reid Spencer | c5b206b | 2006-12-31 05:48:39 +0000 | [diff] [blame] | 237 | Type::Int32Ty, (Type *)0); |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 238 | return true; |
| 239 | } |
| 240 | |
| 241 | // IsTransformableFunction - Return true if the function name isn't one |
| 242 | // of the ones we don't want transformed. Currently, don't transform any |
| 243 | // "llvm.{setjmp,longjmp}" functions and none of the setjmp/longjmp error |
| 244 | // handling functions (beginning with __llvm_sjljeh_...they don't throw |
| 245 | // exceptions). |
Chris Lattner | cb2d1a2 | 2005-04-21 16:46:46 +0000 | [diff] [blame] | 246 | bool LowerSetJmp::IsTransformableFunction(const std::string& Name) { |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 247 | std::string SJLJEh("__llvm_sjljeh"); |
| 248 | |
Chris Lattner | 77b398c | 2003-09-15 05:43:05 +0000 | [diff] [blame] | 249 | if (Name.size() > SJLJEh.size()) |
| 250 | return std::string(Name.begin(), Name.begin() + SJLJEh.size()) != SJLJEh; |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 251 | |
| 252 | return true; |
| 253 | } |
| 254 | |
| 255 | // TransformLongJmpCall - Transform a longjmp call into a call to the |
| 256 | // internal __llvm_sjljeh_throw_longjmp function. It then takes care of |
| 257 | // throwing the exception for us. |
| 258 | void LowerSetJmp::TransformLongJmpCall(CallInst* Inst) |
| 259 | { |
Christopher Lamb | 43ad6b3 | 2007-12-17 01:12:55 +0000 | [diff] [blame] | 260 | const Type* SBPTy = PointerType::getUnqual(Type::Int8Ty); |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 261 | |
| 262 | // Create the call to "__llvm_sjljeh_throw_longjmp". This takes the |
| 263 | // same parameters as "longjmp", except that the buffer is cast to a |
| 264 | // char*. It returns "void", so it doesn't need to replace any of |
| 265 | // Inst's uses and doesn't get a name. |
Reid Spencer | 3da59db | 2006-11-27 01:05:10 +0000 | [diff] [blame] | 266 | CastInst* CI = |
| 267 | new BitCastInst(Inst->getOperand(1), SBPTy, "LJBuf", Inst); |
David Greene | 52eec54 | 2007-08-01 03:43:44 +0000 | [diff] [blame] | 268 | SmallVector<Value *, 2> Args; |
| 269 | Args.push_back(CI); |
| 270 | Args.push_back(Inst->getOperand(2)); |
Gabor Greif | 051a950 | 2008-04-06 20:25:17 +0000 | [diff] [blame^] | 271 | CallInst::Create(ThrowLongJmp, Args.begin(), Args.end(), "", Inst); |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 272 | |
| 273 | SwitchValuePair& SVP = SwitchValMap[Inst->getParent()->getParent()]; |
| 274 | |
| 275 | // If the function has a setjmp call in it (they are transformed first) |
| 276 | // we should branch to the basic block that determines if this longjmp |
| 277 | // is applicable here. Otherwise, issue an unwind. |
| 278 | if (SVP.first) |
Gabor Greif | 051a950 | 2008-04-06 20:25:17 +0000 | [diff] [blame^] | 279 | BranchInst::Create(SVP.first->getParent(), Inst); |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 280 | else |
| 281 | new UnwindInst(Inst); |
| 282 | |
Chris Lattner | 3987abd | 2005-05-05 15:47:43 +0000 | [diff] [blame] | 283 | // Remove all insts after the branch/unwind inst. Go from back to front to |
| 284 | // avoid replaceAllUsesWith if possible. |
| 285 | BasicBlock *BB = Inst->getParent(); |
| 286 | Instruction *Removed; |
| 287 | do { |
| 288 | Removed = &BB->back(); |
| 289 | // If the removed instructions have any users, replace them now. |
| 290 | if (!Removed->use_empty()) |
| 291 | Removed->replaceAllUsesWith(UndefValue::get(Removed->getType())); |
| 292 | Removed->eraseFromParent(); |
| 293 | } while (Removed != Inst); |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 294 | |
| 295 | ++LongJmpsTransformed; |
| 296 | } |
| 297 | |
| 298 | // GetSetJmpMap - Retrieve (create and initialize, if necessary) the |
| 299 | // setjmp map. This map is going to hold information about which setjmps |
| 300 | // were called (each setjmp gets its own number) and with which buffer it |
| 301 | // was called. There can be only one! |
| 302 | AllocaInst* LowerSetJmp::GetSetJmpMap(Function* Func) |
| 303 | { |
| 304 | if (SJMap[Func]) return SJMap[Func]; |
| 305 | |
| 306 | // Insert the setjmp map initialization before the first instruction in |
| 307 | // the function. |
Chris Lattner | 02a3be0 | 2003-09-20 14:39:18 +0000 | [diff] [blame] | 308 | Instruction* Inst = Func->getEntryBlock().begin(); |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 309 | assert(Inst && "Couldn't find even ONE instruction in entry block!"); |
| 310 | |
| 311 | // Fill in the alloca and call to initialize the SJ map. |
Christopher Lamb | 43ad6b3 | 2007-12-17 01:12:55 +0000 | [diff] [blame] | 312 | const Type *SBPTy = PointerType::getUnqual(Type::Int8Ty); |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 313 | AllocaInst* Map = new AllocaInst(SBPTy, 0, "SJMap", Inst); |
Gabor Greif | 051a950 | 2008-04-06 20:25:17 +0000 | [diff] [blame^] | 314 | CallInst::Create(InitSJMap, Map, "", Inst); |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 315 | return SJMap[Func] = Map; |
| 316 | } |
| 317 | |
| 318 | // GetRethrowBB - Only one rethrow basic block is needed per function. |
| 319 | // If this is a longjmp exception but not handled in this block, this BB |
| 320 | // performs the rethrow. |
| 321 | BasicBlock* LowerSetJmp::GetRethrowBB(Function* Func) |
| 322 | { |
| 323 | if (RethrowBBMap[Func]) return RethrowBBMap[Func]; |
| 324 | |
| 325 | // The basic block we're going to jump to if we need to rethrow the |
| 326 | // exception. |
Gabor Greif | 051a950 | 2008-04-06 20:25:17 +0000 | [diff] [blame^] | 327 | BasicBlock* Rethrow = BasicBlock::Create("RethrowExcept", Func); |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 328 | |
| 329 | // Fill in the "Rethrow" BB with a call to rethrow the exception. This |
| 330 | // is the last instruction in the BB since at this point the runtime |
| 331 | // should exit this function and go to the next function. |
Chris Lattner | f8485c6 | 2003-11-20 18:25:24 +0000 | [diff] [blame] | 332 | new UnwindInst(Rethrow); |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 333 | return RethrowBBMap[Func] = Rethrow; |
| 334 | } |
| 335 | |
| 336 | // GetSJSwitch - Return the switch statement that controls which handler |
| 337 | // (if any) gets called and the value returned to that handler. |
| 338 | LowerSetJmp::SwitchValuePair LowerSetJmp::GetSJSwitch(Function* Func, |
| 339 | BasicBlock* Rethrow) |
| 340 | { |
| 341 | if (SwitchValMap[Func].first) return SwitchValMap[Func]; |
| 342 | |
Gabor Greif | 051a950 | 2008-04-06 20:25:17 +0000 | [diff] [blame^] | 343 | BasicBlock* LongJmpPre = BasicBlock::Create("LongJmpBlkPre", Func); |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 344 | BasicBlock::InstListType& LongJmpPreIL = LongJmpPre->getInstList(); |
| 345 | |
| 346 | // Keep track of the preliminary basic block for some of the other |
| 347 | // transformations. |
| 348 | PrelimBBMap[Func] = LongJmpPre; |
| 349 | |
| 350 | // Grab the exception. |
Gabor Greif | 051a950 | 2008-04-06 20:25:17 +0000 | [diff] [blame^] | 351 | CallInst* Cond = CallInst::Create(IsLJException, "IsLJExcept"); |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 352 | LongJmpPreIL.push_back(Cond); |
| 353 | |
| 354 | // The "decision basic block" gets the number associated with the |
| 355 | // setjmp call returning to switch on and the value returned by |
| 356 | // longjmp. |
Gabor Greif | 051a950 | 2008-04-06 20:25:17 +0000 | [diff] [blame^] | 357 | BasicBlock* DecisionBB = BasicBlock::Create("LJDecisionBB", Func); |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 358 | BasicBlock::InstListType& DecisionBBIL = DecisionBB->getInstList(); |
| 359 | |
Gabor Greif | 051a950 | 2008-04-06 20:25:17 +0000 | [diff] [blame^] | 360 | BranchInst::Create(DecisionBB, Rethrow, Cond, LongJmpPre); |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 361 | |
| 362 | // Fill in the "decision" basic block. |
Gabor Greif | 051a950 | 2008-04-06 20:25:17 +0000 | [diff] [blame^] | 363 | CallInst* LJVal = CallInst::Create(GetLJValue, "LJVal"); |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 364 | DecisionBBIL.push_back(LJVal); |
Gabor Greif | 051a950 | 2008-04-06 20:25:17 +0000 | [diff] [blame^] | 365 | CallInst* SJNum = CallInst::Create(TryCatchLJ, GetSetJmpMap(Func), "SJNum"); |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 366 | DecisionBBIL.push_back(SJNum); |
| 367 | |
Gabor Greif | 051a950 | 2008-04-06 20:25:17 +0000 | [diff] [blame^] | 368 | SwitchInst* SI = SwitchInst::Create(SJNum, Rethrow, 0, DecisionBB); |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 369 | return SwitchValMap[Func] = SwitchValuePair(SI, LJVal); |
| 370 | } |
| 371 | |
| 372 | // TransformSetJmpCall - The setjmp call is a bit trickier to transform. |
| 373 | // We're going to convert all setjmp calls to nops. Then all "call" and |
| 374 | // "invoke" instructions in the function are converted to "invoke" where |
| 375 | // the "except" branch is used when returning from a longjmp call. |
| 376 | void LowerSetJmp::TransformSetJmpCall(CallInst* Inst) |
| 377 | { |
| 378 | BasicBlock* ABlock = Inst->getParent(); |
| 379 | Function* Func = ABlock->getParent(); |
| 380 | |
| 381 | // Add this setjmp to the setjmp map. |
Christopher Lamb | 43ad6b3 | 2007-12-17 01:12:55 +0000 | [diff] [blame] | 382 | const Type* SBPTy = PointerType::getUnqual(Type::Int8Ty); |
Reid Spencer | 3da59db | 2006-11-27 01:05:10 +0000 | [diff] [blame] | 383 | CastInst* BufPtr = |
| 384 | new BitCastInst(Inst->getOperand(1), SBPTy, "SBJmpBuf", Inst); |
Chris Lattner | 93e985f | 2007-02-13 02:10:56 +0000 | [diff] [blame] | 385 | std::vector<Value*> Args = |
| 386 | make_vector<Value*>(GetSetJmpMap(Func), BufPtr, |
| 387 | ConstantInt::get(Type::Int32Ty, |
| 388 | SetJmpIDMap[Func]++), 0); |
Gabor Greif | 051a950 | 2008-04-06 20:25:17 +0000 | [diff] [blame^] | 389 | CallInst::Create(AddSJToMap, Args.begin(), Args.end(), "", Inst); |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 390 | |
Chris Lattner | d7222ec | 2003-11-06 19:18:49 +0000 | [diff] [blame] | 391 | // We are guaranteed that there are no values live across basic blocks |
| 392 | // (because we are "not in SSA form" yet), but there can still be values live |
| 393 | // in basic blocks. Because of this, splitting the setjmp block can cause |
| 394 | // values above the setjmp to not dominate uses which are after the setjmp |
| 395 | // call. For all of these occasions, we must spill the value to the stack. |
| 396 | // |
| 397 | std::set<Instruction*> InstrsAfterCall; |
| 398 | |
| 399 | // The call is probably very close to the end of the basic block, for the |
| 400 | // common usage pattern of: 'if (setjmp(...))', so keep track of the |
| 401 | // instructions after the call. |
| 402 | for (BasicBlock::iterator I = ++BasicBlock::iterator(Inst), E = ABlock->end(); |
| 403 | I != E; ++I) |
Misha Brukman | fd93908 | 2005-04-21 23:48:37 +0000 | [diff] [blame] | 404 | InstrsAfterCall.insert(I); |
Chris Lattner | d7222ec | 2003-11-06 19:18:49 +0000 | [diff] [blame] | 405 | |
| 406 | for (BasicBlock::iterator II = ABlock->begin(); |
| 407 | II != BasicBlock::iterator(Inst); ++II) |
| 408 | // Loop over all of the uses of instruction. If any of them are after the |
| 409 | // call, "spill" the value to the stack. |
| 410 | for (Value::use_iterator UI = II->use_begin(), E = II->use_end(); |
| 411 | UI != E; ++UI) |
| 412 | if (cast<Instruction>(*UI)->getParent() != ABlock || |
| 413 | InstrsAfterCall.count(cast<Instruction>(*UI))) { |
| 414 | DemoteRegToStack(*II); |
| 415 | break; |
| 416 | } |
| 417 | InstrsAfterCall.clear(); |
| 418 | |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 419 | // Change the setjmp call into a branch statement. We'll remove the |
| 420 | // setjmp call in a little bit. No worries. |
| 421 | BasicBlock* SetJmpContBlock = ABlock->splitBasicBlock(Inst); |
| 422 | assert(SetJmpContBlock && "Couldn't split setjmp BB!!"); |
| 423 | |
Chris Lattner | cb2d1a2 | 2005-04-21 16:46:46 +0000 | [diff] [blame] | 424 | SetJmpContBlock->setName(ABlock->getName()+"SetJmpCont"); |
| 425 | |
| 426 | // Add the SetJmpContBlock to the set of blocks reachable from a setjmp. |
| 427 | DFSBlocks.insert(SetJmpContBlock); |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 428 | |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 429 | // This PHI node will be in the new block created from the |
| 430 | // splitBasicBlock call. |
Gabor Greif | 051a950 | 2008-04-06 20:25:17 +0000 | [diff] [blame^] | 431 | PHINode* PHI = PHINode::Create(Type::Int32Ty, "SetJmpReturn", Inst); |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 432 | |
| 433 | // Coming from a call to setjmp, the return is 0. |
Reid Spencer | c5b206b | 2006-12-31 05:48:39 +0000 | [diff] [blame] | 434 | PHI->addIncoming(ConstantInt::getNullValue(Type::Int32Ty), ABlock); |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 435 | |
| 436 | // Add the case for this setjmp's number... |
| 437 | SwitchValuePair SVP = GetSJSwitch(Func, GetRethrowBB(Func)); |
Reid Spencer | c5b206b | 2006-12-31 05:48:39 +0000 | [diff] [blame] | 438 | SVP.first->addCase(ConstantInt::get(Type::Int32Ty, SetJmpIDMap[Func] - 1), |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 439 | SetJmpContBlock); |
| 440 | |
| 441 | // Value coming from the handling of the exception. |
| 442 | PHI->addIncoming(SVP.second, SVP.second->getParent()); |
| 443 | |
| 444 | // Replace all uses of this instruction with the PHI node created by |
| 445 | // the eradication of setjmp. |
| 446 | Inst->replaceAllUsesWith(PHI); |
| 447 | Inst->getParent()->getInstList().erase(Inst); |
| 448 | |
| 449 | ++SetJmpsTransformed; |
| 450 | } |
| 451 | |
| 452 | // visitCallInst - This converts all LLVM call instructions into invoke |
| 453 | // instructions. The except part of the invoke goes to the "LongJmpBlkPre" |
| 454 | // that grabs the exception and proceeds to determine if it's a longjmp |
| 455 | // exception or not. |
| 456 | void LowerSetJmp::visitCallInst(CallInst& CI) |
| 457 | { |
| 458 | if (CI.getCalledFunction()) |
| 459 | if (!IsTransformableFunction(CI.getCalledFunction()->getName()) || |
| 460 | CI.getCalledFunction()->isIntrinsic()) return; |
| 461 | |
| 462 | BasicBlock* OldBB = CI.getParent(); |
Chris Lattner | bb2d4de | 2003-10-13 00:57:16 +0000 | [diff] [blame] | 463 | |
| 464 | // If not reachable from a setjmp call, don't transform. |
| 465 | if (!DFSBlocks.count(OldBB)) return; |
| 466 | |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 467 | BasicBlock* NewBB = OldBB->splitBasicBlock(CI); |
| 468 | assert(NewBB && "Couldn't split BB of \"call\" instruction!!"); |
Chris Lattner | d286b24 | 2005-06-15 22:49:30 +0000 | [diff] [blame] | 469 | DFSBlocks.insert(NewBB); |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 470 | NewBB->setName("Call2Invoke"); |
| 471 | |
Chris Lattner | 6d3906b | 2003-10-13 01:02:33 +0000 | [diff] [blame] | 472 | Function* Func = OldBB->getParent(); |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 473 | |
| 474 | // Construct the new "invoke" instruction. |
| 475 | TerminatorInst* Term = OldBB->getTerminator(); |
| 476 | std::vector<Value*> Params(CI.op_begin() + 1, CI.op_end()); |
Gabor Greif | 051a950 | 2008-04-06 20:25:17 +0000 | [diff] [blame^] | 477 | InvokeInst* II = |
| 478 | InvokeInst::Create(CI.getCalledValue(), NewBB, PrelimBBMap[Func], |
| 479 | Params.begin(), Params.end(), CI.getName(), Term); |
Duncan Sands | dc02467 | 2007-11-27 13:23:08 +0000 | [diff] [blame] | 480 | II->setCallingConv(CI.getCallingConv()); |
| 481 | II->setParamAttrs(CI.getParamAttrs()); |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 482 | |
| 483 | // Replace the old call inst with the invoke inst and remove the call. |
| 484 | CI.replaceAllUsesWith(II); |
| 485 | CI.getParent()->getInstList().erase(&CI); |
| 486 | |
| 487 | // The old terminator is useless now that we have the invoke inst. |
| 488 | Term->getParent()->getInstList().erase(Term); |
Chris Lattner | fe2143d | 2003-10-28 23:14:59 +0000 | [diff] [blame] | 489 | ++CallsTransformed; |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 490 | } |
| 491 | |
| 492 | // visitInvokeInst - Converting the "invoke" instruction is fairly |
| 493 | // straight-forward. The old exception part is replaced by a query asking |
| 494 | // if this is a longjmp exception. If it is, then it goes to the longjmp |
| 495 | // exception blocks. Otherwise, control is passed the old exception. |
| 496 | void LowerSetJmp::visitInvokeInst(InvokeInst& II) |
| 497 | { |
| 498 | if (II.getCalledFunction()) |
| 499 | if (!IsTransformableFunction(II.getCalledFunction()->getName()) || |
| 500 | II.getCalledFunction()->isIntrinsic()) return; |
| 501 | |
Chris Lattner | bb2d4de | 2003-10-13 00:57:16 +0000 | [diff] [blame] | 502 | BasicBlock* BB = II.getParent(); |
Chris Lattner | bb2d4de | 2003-10-13 00:57:16 +0000 | [diff] [blame] | 503 | |
| 504 | // If not reachable from a setjmp call, don't transform. |
| 505 | if (!DFSBlocks.count(BB)) return; |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 506 | |
Chris Lattner | aeb2a1d | 2004-02-08 21:44:31 +0000 | [diff] [blame] | 507 | BasicBlock* ExceptBB = II.getUnwindDest(); |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 508 | |
Chris Lattner | 6d3906b | 2003-10-13 01:02:33 +0000 | [diff] [blame] | 509 | Function* Func = BB->getParent(); |
Gabor Greif | 051a950 | 2008-04-06 20:25:17 +0000 | [diff] [blame^] | 510 | BasicBlock* NewExceptBB = BasicBlock::Create("InvokeExcept", Func); |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 511 | BasicBlock::InstListType& InstList = NewExceptBB->getInstList(); |
| 512 | |
| 513 | // If this is a longjmp exception, then branch to the preliminary BB of |
| 514 | // the longjmp exception handling. Otherwise, go to the old exception. |
Gabor Greif | 051a950 | 2008-04-06 20:25:17 +0000 | [diff] [blame^] | 515 | CallInst* IsLJExcept = CallInst::Create(IsLJException, "IsLJExcept"); |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 516 | InstList.push_back(IsLJExcept); |
| 517 | |
Gabor Greif | 051a950 | 2008-04-06 20:25:17 +0000 | [diff] [blame^] | 518 | BranchInst::Create(PrelimBBMap[Func], ExceptBB, IsLJExcept, NewExceptBB); |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 519 | |
Chris Lattner | aeb2a1d | 2004-02-08 21:44:31 +0000 | [diff] [blame] | 520 | II.setUnwindDest(NewExceptBB); |
Chris Lattner | fe2143d | 2003-10-28 23:14:59 +0000 | [diff] [blame] | 521 | ++InvokesTransformed; |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 522 | } |
| 523 | |
| 524 | // visitReturnInst - We want to destroy the setjmp map upon exit from the |
| 525 | // function. |
Chris Lattner | b12914b | 2004-09-20 04:48:05 +0000 | [diff] [blame] | 526 | void LowerSetJmp::visitReturnInst(ReturnInst &RI) { |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 527 | Function* Func = RI.getParent()->getParent(); |
Gabor Greif | 051a950 | 2008-04-06 20:25:17 +0000 | [diff] [blame^] | 528 | CallInst::Create(DestroySJMap, GetSetJmpMap(Func), "", &RI); |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 529 | } |
| 530 | |
| 531 | // visitUnwindInst - We want to destroy the setjmp map upon exit from the |
| 532 | // function. |
Chris Lattner | b12914b | 2004-09-20 04:48:05 +0000 | [diff] [blame] | 533 | void LowerSetJmp::visitUnwindInst(UnwindInst &UI) { |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 534 | Function* Func = UI.getParent()->getParent(); |
Gabor Greif | 051a950 | 2008-04-06 20:25:17 +0000 | [diff] [blame^] | 535 | CallInst::Create(DestroySJMap, GetSetJmpMap(Func), "", &UI); |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 536 | } |
| 537 | |
Chris Lattner | b12914b | 2004-09-20 04:48:05 +0000 | [diff] [blame] | 538 | ModulePass *llvm::createLowerSetJmpPass() { |
Chris Lattner | 6420f1c | 2003-09-15 04:56:27 +0000 | [diff] [blame] | 539 | return new LowerSetJmp(); |
| 540 | } |
Brian Gaeke | d0fde30 | 2003-11-11 22:41:34 +0000 | [diff] [blame] | 541 | |