diff options
Diffstat (limited to 'llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp')
| -rw-r--r-- | llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp | 85 |
1 files changed, 45 insertions, 40 deletions
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp index 68a9b19..8755198 100644 --- a/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp +++ b/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp @@ -50,24 +50,19 @@ /// /// In detail, this pass does following things: /// -/// 1) Assumes the existence of global variables: __THREW__, __threwValue, and -/// __tempRet0. -/// __tempRet0 will be set within __cxa_find_matching_catch() function in -/// JS library, and __THREW__ and __threwValue will be set in invoke wrappers +/// 1) Assumes the existence of global variables: __THREW__, __threwValue +/// __THREW__ and __threwValue will be set in invoke wrappers /// in JS glue code. For what invoke wrappers are, refer to 3). These /// variables are used for both exceptions and setjmp/longjmps. /// __THREW__ indicates whether an exception or a longjmp occurred or not. 0 /// means nothing occurred, 1 means an exception occurred, and other numbers /// mean a longjmp occurred. In the case of longjmp, __threwValue variable /// indicates the corresponding setjmp buffer the longjmp corresponds to. -/// In exception handling, __tempRet0 indicates the type of an exception -/// caught, and in setjmp/longjmp, it means the second argument to longjmp -/// function. /// /// * Exception handling /// -/// 2) We assume the existence of setThrew and setTempRet0 functions at link -/// time. +/// 2) We assume the existence of setThrew and setTempRet0/getTempRet0 functions +/// at link time. /// The global variables in 1) will exist in wasm address space, /// but their values should be set in JS code, so these functions /// as interfaces to JS glue code. These functions are equivalent to the @@ -80,10 +75,12 @@ /// __threwValue = value; /// } /// } +// +/// setTempRet0 is called from __cxa_find_matching_catch() in JS glue code. /// -/// function setTempRet0(value) { -/// __tempRet0 = value; -/// } +/// In exception handling, getTempRet0 indicates the type of an exception +/// caught, and in setjmp/longjmp, it means the second argument to longjmp +/// function. /// /// 3) Lower /// invoke @func(arg1, arg2) to label %invoke.cont unwind label %lpad @@ -120,11 +117,10 @@ /// ... use %val ... /// into /// %fmc = call @__cxa_find_matching_catch_N(c1, c2, c3, ...) -/// %val = {%fmc, __tempRet0} +/// %val = {%fmc, getTempRet0()} /// ... use %val ... /// Here N is a number calculated based on the number of clauses. -/// Global variable __tempRet0 is set within __cxa_find_matching_catch() in -/// JS glue code. +/// setTempRet0 is called from __cxa_find_matching_catch() in JS glue code. /// /// 5) Lower /// resume {%a, %b} @@ -162,15 +158,15 @@ /// setjmp(buf) /// into /// setjmpTable = saveSetjmp(buf, label, setjmpTable, setjmpTableSize); -/// setjmpTableSize = __tempRet0; +/// setjmpTableSize = getTempRet0(); /// For each dynamic setjmp call, setjmpTable stores its ID (a number which /// is incrementally assigned from 0) and its label (a unique number that /// represents each callsite of setjmp). When we need more entries in /// setjmpTable, it is reallocated in saveSetjmp() in JS code and it will /// return the new table address, and assign the new table size in -/// __tempRet0. saveSetjmp also stores the setjmp's ID into the buffer buf. -/// A BB with setjmp is split into two after setjmp call in order to make the -/// post-setjmp BB the possible destination of longjmp BB. +/// setTempRet0(). saveSetjmp also stores the setjmp's ID into the buffer +/// buf. A BB with setjmp is split into two after setjmp call in order to +/// make the post-setjmp BB the possible destination of longjmp BB. /// /// /// 4) Lower every call that might longjmp into @@ -183,11 +179,11 @@ /// setjmpTableSize); /// if (%label == 0) /// emscripten_longjmp(%__THREW__.val, __threwValue); -/// __tempRet0 = __threwValue; +/// setTempRet0(__threwValue); /// } else { /// %label = -1; /// } -/// longjmp_result = __tempRet0; +/// longjmp_result = getTempRet0(); /// switch label { /// label 1: goto post-setjmp BB 1 /// label 2: goto post-setjmp BB 2 @@ -246,7 +242,8 @@ class WebAssemblyLowerEmscriptenEHSjLj final : public ModulePass { GlobalVariable *ThrewGV; GlobalVariable *ThrewValueGV; - GlobalVariable *TempRet0GV; + Function *GetTempRet0Func; + Function *SetTempRet0Func; Function *ResumeF; Function *EHTypeIDF; Function *EmLongjmpF; @@ -286,9 +283,10 @@ public: WebAssemblyLowerEmscriptenEHSjLj(bool EnableEH = true, bool EnableSjLj = true) : ModulePass(ID), EnableEH(EnableEH), EnableSjLj(EnableSjLj), - ThrewGV(nullptr), ThrewValueGV(nullptr), TempRet0GV(nullptr), - ResumeF(nullptr), EHTypeIDF(nullptr), EmLongjmpF(nullptr), - EmLongjmpJmpbufF(nullptr), SaveSetjmpF(nullptr), TestSetjmpF(nullptr) { + ThrewGV(nullptr), ThrewValueGV(nullptr), GetTempRet0Func(nullptr), + SetTempRet0Func(nullptr), ResumeF(nullptr), EHTypeIDF(nullptr), + EmLongjmpF(nullptr), EmLongjmpJmpbufF(nullptr), SaveSetjmpF(nullptr), + TestSetjmpF(nullptr) { EHWhitelistSet.insert(EHWhitelist.begin(), EHWhitelist.end()); } bool runOnModule(Module &M) override; @@ -514,7 +512,8 @@ bool WebAssemblyLowerEmscriptenEHSjLj::canLongjmp(Module &M, Function *ThrowF = M.getFunction("__cxa_throw"); Function *TerminateF = M.getFunction("__clang_call_terminate"); if (Callee == BeginCatchF || Callee == EndCatchF || - Callee == AllocExceptionF || Callee == ThrowF || Callee == TerminateF) + Callee == AllocExceptionF || Callee == ThrowF || Callee == TerminateF || + Callee == GetTempRet0Func || Callee == SetTempRet0Func) return false; // Otherwise we don't know @@ -527,11 +526,11 @@ bool WebAssemblyLowerEmscriptenEHSjLj::canLongjmp(Module &M, // %label = _testSetjmp(mem[%__THREW__.val], setjmpTable, setjmpTableSize); // if (%label == 0) // emscripten_longjmp(%__THREW__.val, threwValue); -// __tempRet0 = threwValue; +// setTempRet0(threwValue); // } else { // %label = -1; // } -// %longjmp_result = __tempRet0; +// %longjmp_result = getTempRet0(); // // As output parameters. returns %label, %longjmp_result, and the BB the last // instruction (%longjmp_result = ...) is in. @@ -575,15 +574,15 @@ void WebAssemblyLowerEmscriptenEHSjLj::wrapTestSetjmp( IRB.CreateCall(EmLongjmpF, {Threw, ThrewValue}); IRB.CreateUnreachable(); - // __tempRet0 = threwValue; + // setTempRet0(threwValue); IRB.SetInsertPoint(EndBB2); - IRB.CreateStore(ThrewValue, TempRet0GV); + IRB.CreateCall(SetTempRet0Func, ThrewValue); IRB.CreateBr(EndBB1); IRB.SetInsertPoint(ElseBB1); IRB.CreateBr(EndBB1); - // longjmp_result = __tempRet0; + // longjmp_result = getTempRet0(); IRB.SetInsertPoint(EndBB1); PHINode *LabelPHI = IRB.CreatePHI(IRB.getInt32Ty(), 2, "label"); LabelPHI->addIncoming(ThenLabel, EndBB2); @@ -593,7 +592,7 @@ void WebAssemblyLowerEmscriptenEHSjLj::wrapTestSetjmp( // Output parameter assignment Label = LabelPHI; EndBB = EndBB1; - LongjmpResult = IRB.CreateLoad(TempRet0GV, "longjmp_result"); + LongjmpResult = IRB.CreateCall(GetTempRet0Func, None, "longjmp_result"); } void WebAssemblyLowerEmscriptenEHSjLj::rebuildSSA(Function &F) { @@ -633,12 +632,19 @@ bool WebAssemblyLowerEmscriptenEHSjLj::runOnModule(Module &M) { bool LongjmpUsed = LongjmpF && !LongjmpF->use_empty(); bool DoSjLj = EnableSjLj && (SetjmpUsed || LongjmpUsed); - // Declare (or get) global variables __THREW__, __threwValue, and __tempRet0, - // which are used in common for both exception handling and setjmp/longjmp - // handling + // Declare (or get) global variables __THREW__, __threwValue, and + // getTempRet0/setTempRet0 function which are used in common for both + // exception handling and setjmp/longjmp handling ThrewGV = getGlobalVariableI32(M, IRB, "__THREW__"); ThrewValueGV = getGlobalVariableI32(M, IRB, "__threwValue"); - TempRet0GV = getGlobalVariableI32(M, IRB, "__tempRet0"); + GetTempRet0Func = + Function::Create(FunctionType::get(IRB.getInt32Ty(), false), + GlobalValue::ExternalLinkage, "getTempRet0", &M); + SetTempRet0Func = Function::Create( + FunctionType::get(IRB.getVoidTy(), IRB.getInt32Ty(), false), + GlobalValue::ExternalLinkage, "setTempRet0", &M); + GetTempRet0Func->setDoesNotThrow(); + SetTempRet0Func->setDoesNotThrow(); bool Changed = false; @@ -848,8 +854,7 @@ bool WebAssemblyLowerEmscriptenEHSjLj::runEHOnFunction(Function &F) { CallInst *FMCI = IRB.CreateCall(FMCF, FMCArgs, "fmc"); Value *Undef = UndefValue::get(LPI->getType()); Value *Pair0 = IRB.CreateInsertValue(Undef, FMCI, 0, "pair0"); - Value *TempRet0 = - IRB.CreateLoad(TempRet0GV, TempRet0GV->getName() + ".val"); + Value *TempRet0 = IRB.CreateCall(GetTempRet0Func, None, "tempret0"); Value *Pair1 = IRB.CreateInsertValue(Pair0, TempRet0, 1, "pair1"); LPI->replaceAllUsesWith(Pair1); @@ -930,7 +935,7 @@ bool WebAssemblyLowerEmscriptenEHSjLj::runSjLjOnFunction(Function &F) { Instruction *NewSetjmpTable = IRB.CreateCall(SaveSetjmpF, Args, "setjmpTable"); Instruction *NewSetjmpTableSize = - IRB.CreateLoad(TempRet0GV, "setjmpTableSize"); + IRB.CreateCall(GetTempRet0Func, None, "setjmpTableSize"); SetjmpTableInsts.push_back(NewSetjmpTable); SetjmpTableSizeInsts.push_back(NewSetjmpTableSize); ToErase.push_back(CI); @@ -1052,7 +1057,7 @@ bool WebAssemblyLowerEmscriptenEHSjLj::runSjLjOnFunction(Function &F) { // ... // somebb: // setjmpTable = saveSetjmp(buf, label, setjmpTable, setjmpTableSize); - // setjmpTableSize = __tempRet0; + // setjmpTableSize = getTempRet0(); // So we need to make sure the SSA for these variables is valid so that every // saveSetjmp and testSetjmp calls have the correct arguments. SSAUpdater SetjmpTableSSA; |