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Chris Lattner6420f1c2003-09-15 04:56:27 +00001//===- LowerSetJmp.cpp - Code pertaining to lowering set/long jumps -------===//
Misha Brukmanfd939082005-04-21 23:48:37 +00002//
John Criswellb576c942003-10-20 19:43:21 +00003// The LLVM Compiler Infrastructure
4//
5// This file was developed by the LLVM research group and is distributed under
6// the University of Illinois Open Source License. See LICENSE.TXT for details.
Misha Brukmanfd939082005-04-21 23:48:37 +00007//
John Criswellb576c942003-10-20 19:43:21 +00008//===----------------------------------------------------------------------===//
Chris Lattner6420f1c2003-09-15 04:56:27 +00009//
10// This file implements the lowering of setjmp and longjmp to use the
Chris Lattner77b398c2003-09-15 05:43:05 +000011// LLVM invoke and unwind instructions as necessary.
Chris Lattner6420f1c2003-09-15 04:56:27 +000012//
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 Lattner1e2385b2003-11-21 21:54:22 +000036#include "llvm/Transforms/IPO.h"
Chris Lattner6420f1c2003-09-15 04:56:27 +000037#include "llvm/Constants.h"
38#include "llvm/DerivedTypes.h"
39#include "llvm/Instructions.h"
40#include "llvm/Intrinsics.h"
41#include "llvm/Module.h"
42#include "llvm/Pass.h"
Chris Lattnerbb2d4de2003-10-13 00:57:16 +000043#include "llvm/Support/CFG.h"
Chris Lattner6420f1c2003-09-15 04:56:27 +000044#include "llvm/Support/InstVisitor.h"
Chris Lattnera2dc7272004-03-14 02:13:38 +000045#include "llvm/Transforms/Utils/Local.h"
Reid Spencer551ccae2004-09-01 22:55:40 +000046#include "llvm/ADT/DepthFirstIterator.h"
47#include "llvm/ADT/Statistic.h"
48#include "llvm/ADT/StringExtras.h"
49#include "llvm/ADT/VectorExtras.h"
Chris Lattner1e2385b2003-11-21 21:54:22 +000050using namespace llvm;
Brian Gaeked0fde302003-11-11 22:41:34 +000051
Chris Lattner6420f1c2003-09-15 04:56:27 +000052namespace {
53 Statistic<> LongJmpsTransformed("lowersetjmp",
54 "Number of longjmps transformed");
55 Statistic<> SetJmpsTransformed("lowersetjmp",
56 "Number of setjmps transformed");
Chris Lattnerfe2143d2003-10-28 23:14:59 +000057 Statistic<> CallsTransformed("lowersetjmp",
58 "Number of calls invokified");
59 Statistic<> InvokesTransformed("lowersetjmp",
60 "Number of invokes modified");
Chris Lattner6420f1c2003-09-15 04:56:27 +000061
62 //===--------------------------------------------------------------------===//
Chris Lattnerbc53e5e2004-10-07 06:00:24 +000063 // LowerSetJmp pass implementation.
Chris Lattnerb12914b2004-09-20 04:48:05 +000064 class LowerSetJmp : public ModulePass,
Chris Lattner6420f1c2003-09-15 04:56:27 +000065 public InstVisitor<LowerSetJmp> {
66 // LLVM library functions...
67 Function* InitSJMap; // __llvm_sjljeh_init_setjmpmap
68 Function* DestroySJMap; // __llvm_sjljeh_destroy_setjmpmap
69 Function* AddSJToMap; // __llvm_sjljeh_add_setjmp_to_map
70 Function* ThrowLongJmp; // __llvm_sjljeh_throw_longjmp
71 Function* TryCatchLJ; // __llvm_sjljeh_try_catching_longjmp_exception
72 Function* IsLJException; // __llvm_sjljeh_is_longjmp_exception
73 Function* GetLJValue; // __llvm_sjljeh_get_longjmp_value
74
75 typedef std::pair<SwitchInst*, CallInst*> SwitchValuePair;
76
Chris Lattnerbb2d4de2003-10-13 00:57:16 +000077 // 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 Lattner6420f1c2003-09-15 04:56:27 +000082 // 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:
114 void visitCallInst(CallInst& CI);
115 void visitInvokeInst(InvokeInst& II);
116 void visitReturnInst(ReturnInst& RI);
117 void visitUnwindInst(UnwindInst& UI);
118
Chris Lattnerb12914b2004-09-20 04:48:05 +0000119 bool runOnModule(Module& M);
Chris Lattner6420f1c2003-09-15 04:56:27 +0000120 bool doInitialization(Module& M);
121 };
122
Chris Lattner7f8897f2006-08-27 22:42:52 +0000123 RegisterPass<LowerSetJmp> X("lowersetjmp", "Lower Set Jump");
Chris Lattner6420f1c2003-09-15 04:56:27 +0000124} // end anonymous namespace
125
126// run - Run the transformation on the program. We grab the function
127// prototypes for longjmp and setjmp. If they are used in the program,
128// then we can go directly to the places they're at and transform them.
Chris Lattnerb12914b2004-09-20 04:48:05 +0000129bool LowerSetJmp::runOnModule(Module& M) {
Chris Lattner6420f1c2003-09-15 04:56:27 +0000130 bool Changed = false;
131
132 // These are what the functions are called.
133 Function* SetJmp = M.getNamedFunction("llvm.setjmp");
134 Function* LongJmp = M.getNamedFunction("llvm.longjmp");
135
136 // This program doesn't have longjmp and setjmp calls.
137 if ((!LongJmp || LongJmp->use_empty()) &&
138 (!SetJmp || SetJmp->use_empty())) return false;
139
140 // Initialize some values and functions we'll need to transform the
141 // setjmp/longjmp functions.
142 doInitialization(M);
143
Chris Lattnerbb2d4de2003-10-13 00:57:16 +0000144 if (SetJmp) {
Chris Lattnerbb2d4de2003-10-13 00:57:16 +0000145 for (Value::use_iterator B = SetJmp->use_begin(), E = SetJmp->use_end();
146 B != E; ++B) {
Chris Lattner6d3906b2003-10-13 01:02:33 +0000147 BasicBlock* BB = cast<Instruction>(*B)->getParent();
Chris Lattner8b716f62003-10-13 16:49:21 +0000148 for (df_ext_iterator<BasicBlock*> I = df_ext_begin(BB, DFSBlocks),
149 E = df_ext_end(BB, DFSBlocks); I != E; ++I)
Chris Lattner46e033d2003-10-13 16:44:50 +0000150 /* empty */;
Chris Lattnerbb2d4de2003-10-13 00:57:16 +0000151 }
152
Chris Lattner6420f1c2003-09-15 04:56:27 +0000153 while (!SetJmp->use_empty()) {
154 assert(isa<CallInst>(SetJmp->use_back()) &&
155 "User of setjmp intrinsic not a call?");
156 TransformSetJmpCall(cast<CallInst>(SetJmp->use_back()));
157 Changed = true;
158 }
Chris Lattnerbb2d4de2003-10-13 00:57:16 +0000159 }
Chris Lattner6420f1c2003-09-15 04:56:27 +0000160
161 if (LongJmp)
162 while (!LongJmp->use_empty()) {
163 assert(isa<CallInst>(LongJmp->use_back()) &&
164 "User of longjmp intrinsic not a call?");
165 TransformLongJmpCall(cast<CallInst>(LongJmp->use_back()));
166 Changed = true;
167 }
168
169 // Now go through the affected functions and convert calls and invokes
170 // to new invokes...
171 for (std::map<Function*, AllocaInst*>::iterator
172 B = SJMap.begin(), E = SJMap.end(); B != E; ++B) {
173 Function* F = B->first;
174 for (Function::iterator BB = F->begin(), BE = F->end(); BB != BE; ++BB)
175 for (BasicBlock::iterator IB = BB->begin(), IE = BB->end(); IB != IE; ) {
176 visit(*IB++);
177 if (IB != BB->end() && IB->getParent() != BB)
178 break; // The next instruction got moved to a different block!
179 }
180 }
181
Chris Lattnerbb2d4de2003-10-13 00:57:16 +0000182 DFSBlocks.clear();
Chris Lattner6420f1c2003-09-15 04:56:27 +0000183 SJMap.clear();
184 RethrowBBMap.clear();
185 PrelimBBMap.clear();
186 SwitchValMap.clear();
187 SetJmpIDMap.clear();
188
189 return Changed;
190}
191
192// doInitialization - For the lower long/setjmp pass, this ensures that a
193// module contains a declaration for the intrisic functions we are going
194// to call to convert longjmp and setjmp calls.
195//
196// This function is always successful, unless it isn't.
197bool LowerSetJmp::doInitialization(Module& M)
198{
199 const Type *SBPTy = PointerType::get(Type::SByteTy);
200 const Type *SBPPTy = PointerType::get(SBPTy);
201
202 // N.B. See llvm/runtime/GCCLibraries/libexception/SJLJ-Exception.h for
203 // a description of the following library functions.
204
205 // void __llvm_sjljeh_init_setjmpmap(void**)
206 InitSJMap = M.getOrInsertFunction("__llvm_sjljeh_init_setjmpmap",
Jeff Cohen66c5fd62005-10-23 04:37:20 +0000207 Type::VoidTy, SBPPTy, (Type *)0);
Chris Lattner6420f1c2003-09-15 04:56:27 +0000208 // void __llvm_sjljeh_destroy_setjmpmap(void**)
209 DestroySJMap = M.getOrInsertFunction("__llvm_sjljeh_destroy_setjmpmap",
Jeff Cohen66c5fd62005-10-23 04:37:20 +0000210 Type::VoidTy, SBPPTy, (Type *)0);
Chris Lattner6420f1c2003-09-15 04:56:27 +0000211
212 // void __llvm_sjljeh_add_setjmp_to_map(void**, void*, unsigned)
213 AddSJToMap = M.getOrInsertFunction("__llvm_sjljeh_add_setjmp_to_map",
214 Type::VoidTy, SBPPTy, SBPTy,
Jeff Cohen66c5fd62005-10-23 04:37:20 +0000215 Type::UIntTy, (Type *)0);
Chris Lattner6420f1c2003-09-15 04:56:27 +0000216
217 // void __llvm_sjljeh_throw_longjmp(int*, int)
218 ThrowLongJmp = M.getOrInsertFunction("__llvm_sjljeh_throw_longjmp",
Jeff Cohen66c5fd62005-10-23 04:37:20 +0000219 Type::VoidTy, SBPTy, Type::IntTy,
220 (Type *)0);
Chris Lattner6420f1c2003-09-15 04:56:27 +0000221
222 // unsigned __llvm_sjljeh_try_catching_longjmp_exception(void **)
223 TryCatchLJ =
224 M.getOrInsertFunction("__llvm_sjljeh_try_catching_longjmp_exception",
Jeff Cohen66c5fd62005-10-23 04:37:20 +0000225 Type::UIntTy, SBPPTy, (Type *)0);
Chris Lattner6420f1c2003-09-15 04:56:27 +0000226
227 // bool __llvm_sjljeh_is_longjmp_exception()
228 IsLJException = M.getOrInsertFunction("__llvm_sjljeh_is_longjmp_exception",
Jeff Cohen66c5fd62005-10-23 04:37:20 +0000229 Type::BoolTy, (Type *)0);
Chris Lattner6420f1c2003-09-15 04:56:27 +0000230
231 // int __llvm_sjljeh_get_longjmp_value()
232 GetLJValue = M.getOrInsertFunction("__llvm_sjljeh_get_longjmp_value",
Jeff Cohen66c5fd62005-10-23 04:37:20 +0000233 Type::IntTy, (Type *)0);
Chris Lattner6420f1c2003-09-15 04:56:27 +0000234 return true;
235}
236
237// IsTransformableFunction - Return true if the function name isn't one
238// of the ones we don't want transformed. Currently, don't transform any
239// "llvm.{setjmp,longjmp}" functions and none of the setjmp/longjmp error
240// handling functions (beginning with __llvm_sjljeh_...they don't throw
241// exceptions).
Chris Lattnercb2d1a22005-04-21 16:46:46 +0000242bool LowerSetJmp::IsTransformableFunction(const std::string& Name) {
Chris Lattner6420f1c2003-09-15 04:56:27 +0000243 std::string SJLJEh("__llvm_sjljeh");
244
Chris Lattner77b398c2003-09-15 05:43:05 +0000245 if (Name.size() > SJLJEh.size())
246 return std::string(Name.begin(), Name.begin() + SJLJEh.size()) != SJLJEh;
Chris Lattner6420f1c2003-09-15 04:56:27 +0000247
248 return true;
249}
250
251// TransformLongJmpCall - Transform a longjmp call into a call to the
252// internal __llvm_sjljeh_throw_longjmp function. It then takes care of
253// throwing the exception for us.
254void LowerSetJmp::TransformLongJmpCall(CallInst* Inst)
255{
256 const Type* SBPTy = PointerType::get(Type::SByteTy);
257
258 // Create the call to "__llvm_sjljeh_throw_longjmp". This takes the
259 // same parameters as "longjmp", except that the buffer is cast to a
260 // char*. It returns "void", so it doesn't need to replace any of
261 // Inst's uses and doesn't get a name.
262 CastInst* CI = new CastInst(Inst->getOperand(1), SBPTy, "LJBuf", Inst);
263 new CallInst(ThrowLongJmp, make_vector<Value*>(CI, Inst->getOperand(2), 0),
264 "", Inst);
265
266 SwitchValuePair& SVP = SwitchValMap[Inst->getParent()->getParent()];
267
268 // If the function has a setjmp call in it (they are transformed first)
269 // we should branch to the basic block that determines if this longjmp
270 // is applicable here. Otherwise, issue an unwind.
271 if (SVP.first)
272 new BranchInst(SVP.first->getParent(), Inst);
273 else
274 new UnwindInst(Inst);
275
Chris Lattner3987abd2005-05-05 15:47:43 +0000276 // Remove all insts after the branch/unwind inst. Go from back to front to
277 // avoid replaceAllUsesWith if possible.
278 BasicBlock *BB = Inst->getParent();
279 Instruction *Removed;
280 do {
281 Removed = &BB->back();
282 // If the removed instructions have any users, replace them now.
283 if (!Removed->use_empty())
284 Removed->replaceAllUsesWith(UndefValue::get(Removed->getType()));
285 Removed->eraseFromParent();
286 } while (Removed != Inst);
Chris Lattner6420f1c2003-09-15 04:56:27 +0000287
288 ++LongJmpsTransformed;
289}
290
291// GetSetJmpMap - Retrieve (create and initialize, if necessary) the
292// setjmp map. This map is going to hold information about which setjmps
293// were called (each setjmp gets its own number) and with which buffer it
294// was called. There can be only one!
295AllocaInst* LowerSetJmp::GetSetJmpMap(Function* Func)
296{
297 if (SJMap[Func]) return SJMap[Func];
298
299 // Insert the setjmp map initialization before the first instruction in
300 // the function.
Chris Lattner02a3be02003-09-20 14:39:18 +0000301 Instruction* Inst = Func->getEntryBlock().begin();
Chris Lattner6420f1c2003-09-15 04:56:27 +0000302 assert(Inst && "Couldn't find even ONE instruction in entry block!");
303
304 // Fill in the alloca and call to initialize the SJ map.
305 const Type *SBPTy = PointerType::get(Type::SByteTy);
306 AllocaInst* Map = new AllocaInst(SBPTy, 0, "SJMap", Inst);
307 new CallInst(InitSJMap, make_vector<Value*>(Map, 0), "", Inst);
308 return SJMap[Func] = Map;
309}
310
311// GetRethrowBB - Only one rethrow basic block is needed per function.
312// If this is a longjmp exception but not handled in this block, this BB
313// performs the rethrow.
314BasicBlock* LowerSetJmp::GetRethrowBB(Function* Func)
315{
316 if (RethrowBBMap[Func]) return RethrowBBMap[Func];
317
318 // The basic block we're going to jump to if we need to rethrow the
319 // exception.
320 BasicBlock* Rethrow = new BasicBlock("RethrowExcept", Func);
Chris Lattner6420f1c2003-09-15 04:56:27 +0000321
322 // Fill in the "Rethrow" BB with a call to rethrow the exception. This
323 // is the last instruction in the BB since at this point the runtime
324 // should exit this function and go to the next function.
Chris Lattnerf8485c62003-11-20 18:25:24 +0000325 new UnwindInst(Rethrow);
Chris Lattner6420f1c2003-09-15 04:56:27 +0000326 return RethrowBBMap[Func] = Rethrow;
327}
328
329// GetSJSwitch - Return the switch statement that controls which handler
330// (if any) gets called and the value returned to that handler.
331LowerSetJmp::SwitchValuePair LowerSetJmp::GetSJSwitch(Function* Func,
332 BasicBlock* Rethrow)
333{
334 if (SwitchValMap[Func].first) return SwitchValMap[Func];
335
336 BasicBlock* LongJmpPre = new BasicBlock("LongJmpBlkPre", Func);
337 BasicBlock::InstListType& LongJmpPreIL = LongJmpPre->getInstList();
338
339 // Keep track of the preliminary basic block for some of the other
340 // transformations.
341 PrelimBBMap[Func] = LongJmpPre;
342
343 // Grab the exception.
344 CallInst* Cond = new
345 CallInst(IsLJException, std::vector<Value*>(), "IsLJExcept");
346 LongJmpPreIL.push_back(Cond);
347
348 // The "decision basic block" gets the number associated with the
349 // setjmp call returning to switch on and the value returned by
350 // longjmp.
351 BasicBlock* DecisionBB = new BasicBlock("LJDecisionBB", Func);
352 BasicBlock::InstListType& DecisionBBIL = DecisionBB->getInstList();
353
Chris Lattnerf8485c62003-11-20 18:25:24 +0000354 new BranchInst(DecisionBB, Rethrow, Cond, LongJmpPre);
Chris Lattner6420f1c2003-09-15 04:56:27 +0000355
356 // Fill in the "decision" basic block.
357 CallInst* LJVal = new CallInst(GetLJValue, std::vector<Value*>(), "LJVal");
358 DecisionBBIL.push_back(LJVal);
359 CallInst* SJNum = new
360 CallInst(TryCatchLJ, make_vector<Value*>(GetSetJmpMap(Func), 0), "SJNum");
361 DecisionBBIL.push_back(SJNum);
362
Chris Lattner667fdae2005-01-29 00:38:45 +0000363 SwitchInst* SI = new SwitchInst(SJNum, Rethrow, 0, DecisionBB);
Chris Lattner6420f1c2003-09-15 04:56:27 +0000364 return SwitchValMap[Func] = SwitchValuePair(SI, LJVal);
365}
366
367// TransformSetJmpCall - The setjmp call is a bit trickier to transform.
368// We're going to convert all setjmp calls to nops. Then all "call" and
369// "invoke" instructions in the function are converted to "invoke" where
370// the "except" branch is used when returning from a longjmp call.
371void LowerSetJmp::TransformSetJmpCall(CallInst* Inst)
372{
373 BasicBlock* ABlock = Inst->getParent();
374 Function* Func = ABlock->getParent();
375
376 // Add this setjmp to the setjmp map.
377 const Type* SBPTy = PointerType::get(Type::SByteTy);
378 CastInst* BufPtr = new CastInst(Inst->getOperand(1), SBPTy, "SBJmpBuf", Inst);
379 new CallInst(AddSJToMap,
380 make_vector<Value*>(GetSetJmpMap(Func), BufPtr,
Reid Spencerb83eb642006-10-20 07:07:24 +0000381 ConstantInt::get(Type::UIntTy,
Chris Lattner6420f1c2003-09-15 04:56:27 +0000382 SetJmpIDMap[Func]++), 0),
383 "", Inst);
384
Chris Lattnerd7222ec2003-11-06 19:18:49 +0000385 // We are guaranteed that there are no values live across basic blocks
386 // (because we are "not in SSA form" yet), but there can still be values live
387 // in basic blocks. Because of this, splitting the setjmp block can cause
388 // values above the setjmp to not dominate uses which are after the setjmp
389 // call. For all of these occasions, we must spill the value to the stack.
390 //
391 std::set<Instruction*> InstrsAfterCall;
392
393 // The call is probably very close to the end of the basic block, for the
394 // common usage pattern of: 'if (setjmp(...))', so keep track of the
395 // instructions after the call.
396 for (BasicBlock::iterator I = ++BasicBlock::iterator(Inst), E = ABlock->end();
397 I != E; ++I)
Misha Brukmanfd939082005-04-21 23:48:37 +0000398 InstrsAfterCall.insert(I);
Chris Lattnerd7222ec2003-11-06 19:18:49 +0000399
400 for (BasicBlock::iterator II = ABlock->begin();
401 II != BasicBlock::iterator(Inst); ++II)
402 // Loop over all of the uses of instruction. If any of them are after the
403 // call, "spill" the value to the stack.
404 for (Value::use_iterator UI = II->use_begin(), E = II->use_end();
405 UI != E; ++UI)
406 if (cast<Instruction>(*UI)->getParent() != ABlock ||
407 InstrsAfterCall.count(cast<Instruction>(*UI))) {
408 DemoteRegToStack(*II);
409 break;
410 }
411 InstrsAfterCall.clear();
412
Chris Lattner6420f1c2003-09-15 04:56:27 +0000413 // Change the setjmp call into a branch statement. We'll remove the
414 // setjmp call in a little bit. No worries.
415 BasicBlock* SetJmpContBlock = ABlock->splitBasicBlock(Inst);
416 assert(SetJmpContBlock && "Couldn't split setjmp BB!!");
417
Chris Lattnercb2d1a22005-04-21 16:46:46 +0000418 SetJmpContBlock->setName(ABlock->getName()+"SetJmpCont");
419
420 // Add the SetJmpContBlock to the set of blocks reachable from a setjmp.
421 DFSBlocks.insert(SetJmpContBlock);
Chris Lattner6420f1c2003-09-15 04:56:27 +0000422
Chris Lattner6420f1c2003-09-15 04:56:27 +0000423 // This PHI node will be in the new block created from the
424 // splitBasicBlock call.
425 PHINode* PHI = new PHINode(Type::IntTy, "SetJmpReturn", Inst);
426
427 // Coming from a call to setjmp, the return is 0.
428 PHI->addIncoming(ConstantInt::getNullValue(Type::IntTy), ABlock);
429
430 // Add the case for this setjmp's number...
431 SwitchValuePair SVP = GetSJSwitch(Func, GetRethrowBB(Func));
Reid Spencerb83eb642006-10-20 07:07:24 +0000432 SVP.first->addCase(ConstantInt::get(Type::UIntTy, SetJmpIDMap[Func] - 1),
Chris Lattner6420f1c2003-09-15 04:56:27 +0000433 SetJmpContBlock);
434
435 // Value coming from the handling of the exception.
436 PHI->addIncoming(SVP.second, SVP.second->getParent());
437
438 // Replace all uses of this instruction with the PHI node created by
439 // the eradication of setjmp.
440 Inst->replaceAllUsesWith(PHI);
441 Inst->getParent()->getInstList().erase(Inst);
442
443 ++SetJmpsTransformed;
444}
445
446// visitCallInst - This converts all LLVM call instructions into invoke
447// instructions. The except part of the invoke goes to the "LongJmpBlkPre"
448// that grabs the exception and proceeds to determine if it's a longjmp
449// exception or not.
450void LowerSetJmp::visitCallInst(CallInst& CI)
451{
452 if (CI.getCalledFunction())
453 if (!IsTransformableFunction(CI.getCalledFunction()->getName()) ||
454 CI.getCalledFunction()->isIntrinsic()) return;
455
456 BasicBlock* OldBB = CI.getParent();
Chris Lattnerbb2d4de2003-10-13 00:57:16 +0000457
458 // If not reachable from a setjmp call, don't transform.
459 if (!DFSBlocks.count(OldBB)) return;
460
Chris Lattner6420f1c2003-09-15 04:56:27 +0000461 BasicBlock* NewBB = OldBB->splitBasicBlock(CI);
462 assert(NewBB && "Couldn't split BB of \"call\" instruction!!");
Chris Lattnerd286b242005-06-15 22:49:30 +0000463 DFSBlocks.insert(NewBB);
Chris Lattner6420f1c2003-09-15 04:56:27 +0000464 NewBB->setName("Call2Invoke");
465
Chris Lattner6d3906b2003-10-13 01:02:33 +0000466 Function* Func = OldBB->getParent();
Chris Lattner6420f1c2003-09-15 04:56:27 +0000467
468 // Construct the new "invoke" instruction.
469 TerminatorInst* Term = OldBB->getTerminator();
470 std::vector<Value*> Params(CI.op_begin() + 1, CI.op_end());
471 InvokeInst* II = new
472 InvokeInst(CI.getCalledValue(), NewBB, PrelimBBMap[Func],
Misha Brukmanfd939082005-04-21 23:48:37 +0000473 Params, CI.getName(), Term);
Chris Lattner6420f1c2003-09-15 04:56:27 +0000474
475 // Replace the old call inst with the invoke inst and remove the call.
476 CI.replaceAllUsesWith(II);
477 CI.getParent()->getInstList().erase(&CI);
478
479 // The old terminator is useless now that we have the invoke inst.
480 Term->getParent()->getInstList().erase(Term);
Chris Lattnerfe2143d2003-10-28 23:14:59 +0000481 ++CallsTransformed;
Chris Lattner6420f1c2003-09-15 04:56:27 +0000482}
483
484// visitInvokeInst - Converting the "invoke" instruction is fairly
485// straight-forward. The old exception part is replaced by a query asking
486// if this is a longjmp exception. If it is, then it goes to the longjmp
487// exception blocks. Otherwise, control is passed the old exception.
488void LowerSetJmp::visitInvokeInst(InvokeInst& II)
489{
490 if (II.getCalledFunction())
491 if (!IsTransformableFunction(II.getCalledFunction()->getName()) ||
492 II.getCalledFunction()->isIntrinsic()) return;
493
Chris Lattnerbb2d4de2003-10-13 00:57:16 +0000494 BasicBlock* BB = II.getParent();
Chris Lattnerbb2d4de2003-10-13 00:57:16 +0000495
496 // If not reachable from a setjmp call, don't transform.
497 if (!DFSBlocks.count(BB)) return;
Chris Lattner6420f1c2003-09-15 04:56:27 +0000498
499 BasicBlock* NormalBB = II.getNormalDest();
Chris Lattneraeb2a1d2004-02-08 21:44:31 +0000500 BasicBlock* ExceptBB = II.getUnwindDest();
Chris Lattner6420f1c2003-09-15 04:56:27 +0000501
Chris Lattner6d3906b2003-10-13 01:02:33 +0000502 Function* Func = BB->getParent();
Chris Lattner6420f1c2003-09-15 04:56:27 +0000503 BasicBlock* NewExceptBB = new BasicBlock("InvokeExcept", Func);
504 BasicBlock::InstListType& InstList = NewExceptBB->getInstList();
505
506 // If this is a longjmp exception, then branch to the preliminary BB of
507 // the longjmp exception handling. Otherwise, go to the old exception.
508 CallInst* IsLJExcept = new
509 CallInst(IsLJException, std::vector<Value*>(), "IsLJExcept");
510 InstList.push_back(IsLJExcept);
511
Chris Lattnerf8485c62003-11-20 18:25:24 +0000512 new BranchInst(PrelimBBMap[Func], ExceptBB, IsLJExcept, NewExceptBB);
Chris Lattner6420f1c2003-09-15 04:56:27 +0000513
Chris Lattneraeb2a1d2004-02-08 21:44:31 +0000514 II.setUnwindDest(NewExceptBB);
Chris Lattnerfe2143d2003-10-28 23:14:59 +0000515 ++InvokesTransformed;
Chris Lattner6420f1c2003-09-15 04:56:27 +0000516}
517
518// visitReturnInst - We want to destroy the setjmp map upon exit from the
519// function.
Chris Lattnerb12914b2004-09-20 04:48:05 +0000520void LowerSetJmp::visitReturnInst(ReturnInst &RI) {
Chris Lattner6420f1c2003-09-15 04:56:27 +0000521 Function* Func = RI.getParent()->getParent();
522 new CallInst(DestroySJMap, make_vector<Value*>(GetSetJmpMap(Func), 0),
523 "", &RI);
524}
525
526// visitUnwindInst - We want to destroy the setjmp map upon exit from the
527// function.
Chris Lattnerb12914b2004-09-20 04:48:05 +0000528void LowerSetJmp::visitUnwindInst(UnwindInst &UI) {
Chris Lattner6420f1c2003-09-15 04:56:27 +0000529 Function* Func = UI.getParent()->getParent();
530 new CallInst(DestroySJMap, make_vector<Value*>(GetSetJmpMap(Func), 0),
531 "", &UI);
532}
533
Chris Lattnerb12914b2004-09-20 04:48:05 +0000534ModulePass *llvm::createLowerSetJmpPass() {
Chris Lattner6420f1c2003-09-15 04:56:27 +0000535 return new LowerSetJmp();
536}
Brian Gaeked0fde302003-11-11 22:41:34 +0000537