From 4cc4666268c6c62de763c46fefe304adf08a01a1 Mon Sep 17 00:00:00 2001 From: Bill Wendling Date: Fri, 27 Jan 2012 02:02:24 +0000 Subject: [PATCH] Place the GEP instructions nearer to the instructions which use them. GEP instructions are there for the compiler and shouldn't really output much code (if any at all). When a GEP is stored in the entry block, Fast ISel (for one) will not know that it could fold it into further uses. For instance, inside of the EH handling code. This results in a lot of unnecessary spills and loads which bloat code and slows down pretty much everything. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149114 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/SjLjEHPrepare.cpp | 73 +++++++++++++++++------------------ 1 file changed, 36 insertions(+), 37 deletions(-) diff --git a/lib/CodeGen/SjLjEHPrepare.cpp b/lib/CodeGen/SjLjEHPrepare.cpp index b944fa0740e..5412c97ef5e 100644 --- a/lib/CodeGen/SjLjEHPrepare.cpp +++ b/lib/CodeGen/SjLjEHPrepare.cpp @@ -55,7 +55,7 @@ namespace { Value *PersonalityFn; Constant *CallSiteFn; Constant *FuncCtxFn; - Value *CallSite; + AllocaInst *FuncCtx; public: static char ID; // Pass identification, replacement for typeid explicit SjLjEHPass(const TargetLowering *tli = NULL) @@ -75,7 +75,7 @@ namespace { Value *setupFunctionContext(Function &F, ArrayRef LPads); void lowerIncomingArguments(Function &F); void lowerAcrossUnwindEdges(Function &F, ArrayRef Invokes); - void insertCallSiteStore(Instruction *I, int Number, Value *CallSite); + void insertCallSiteStore(Instruction *I, int Number); }; } // end anonymous namespace @@ -123,12 +123,20 @@ bool SjLjEHPass::doInitialization(Module &M) { /// insertCallSiteStore - Insert a store of the call-site value to the /// function context -void SjLjEHPass::insertCallSiteStore(Instruction *I, int Number, - Value *CallSite) { +void SjLjEHPass::insertCallSiteStore(Instruction *I, int Number) { + IRBuilder<> Builder(I); + + // Get a reference to the call_site field. + Type *Int32Ty = Type::getInt32Ty(I->getContext()); + Value *Zero = ConstantInt::get(Int32Ty, 0); + Value *One = ConstantInt::get(Int32Ty, 1); + Value *Idxs[2] = { Zero, One }; + Value *CallSite = Builder.CreateGEP(FuncCtx, Idxs, "call_site"); + + // Insert a store of the call-site number ConstantInt *CallSiteNoC = ConstantInt::get(Type::getInt32Ty(I->getContext()), Number); - // Insert a store of the call-site number - new StoreInst(CallSiteNoC, CallSite, true, I); // volatile + Builder.CreateStore(CallSiteNoC, CallSite, true/*volatile*/); } /// MarkBlocksLiveIn - Insert BB and all of its predescessors into LiveBBs until @@ -184,51 +192,42 @@ setupFunctionContext(Function &F, ArrayRef LPads) { // because the value needs to be added to the global context list. unsigned Align = TLI->getTargetData()->getPrefTypeAlignment(FunctionContextTy); - AllocaInst *FuncCtx = + FuncCtx = new AllocaInst(FunctionContextTy, 0, Align, "fn_context", EntryBB->begin()); // Fill in the function context structure. - Value *Idxs[2]; Type *Int32Ty = Type::getInt32Ty(F.getContext()); Value *Zero = ConstantInt::get(Int32Ty, 0); Value *One = ConstantInt::get(Int32Ty, 1); + Value *Two = ConstantInt::get(Int32Ty, 2); + Value *Three = ConstantInt::get(Int32Ty, 3); + Value *Four = ConstantInt::get(Int32Ty, 4); - // Keep around a reference to the call_site field. - Idxs[0] = Zero; - Idxs[1] = One; - CallSite = GetElementPtrInst::Create(FuncCtx, Idxs, "call_site", - EntryBB->getTerminator()); - - // Reference the __data field. - Idxs[1] = ConstantInt::get(Int32Ty, 2); - Value *FCData = GetElementPtrInst::Create(FuncCtx, Idxs, "__data", - EntryBB->getTerminator()); - - // The exception value comes back in context->__data[0]. - Idxs[1] = Zero; - Value *ExceptionAddr = GetElementPtrInst::Create(FCData, Idxs, - "exception_gep", - EntryBB->getTerminator()); - - // The exception selector comes back in context->__data[1]. - Idxs[1] = One; - Value *SelectorAddr = GetElementPtrInst::Create(FCData, Idxs, - "exn_selector_gep", - EntryBB->getTerminator()); + Value *Idxs[2] = { Zero, 0 }; for (unsigned I = 0, E = LPads.size(); I != E; ++I) { LandingPadInst *LPI = LPads[I]; IRBuilder<> Builder(LPI->getParent()->getFirstInsertionPt()); + // Reference the __data field. + Idxs[1] = Two; + Value *FCData = Builder.CreateGEP(FuncCtx, Idxs, "__data"); + + // The exception values come back in context->__data[0]. + Idxs[1] = Zero; + Value *ExceptionAddr = Builder.CreateGEP(FCData, Idxs, "exception_gep"); Value *ExnVal = Builder.CreateLoad(ExceptionAddr, true, "exn_val"); ExnVal = Builder.CreateIntToPtr(ExnVal, Type::getInt8PtrTy(F.getContext())); + + Idxs[1] = One; + Value *SelectorAddr = Builder.CreateGEP(FCData, Idxs, "exn_selector_gep"); Value *SelVal = Builder.CreateLoad(SelectorAddr, true, "exn_selector_val"); substituteLPadValues(LPI, ExnVal, SelVal); } // Personality function - Idxs[1] = ConstantInt::get(Int32Ty, 3); + Idxs[1] = Three; if (!PersonalityFn) PersonalityFn = LPads[0]->getPersonalityFn(); Value *PersonalityFieldPtr = @@ -238,11 +237,11 @@ setupFunctionContext(Function &F, ArrayRef LPads) { EntryBB->getTerminator()); // LSDA address - Idxs[1] = ConstantInt::get(Int32Ty, 4); - Value *LSDAFieldPtr = GetElementPtrInst::Create(FuncCtx, Idxs, "lsda_gep", - EntryBB->getTerminator()); Value *LSDA = CallInst::Create(LSDAAddrFn, "lsda_addr", EntryBB->getTerminator()); + Idxs[1] = Four; + Value *LSDAFieldPtr = GetElementPtrInst::Create(FuncCtx, Idxs, "lsda_gep", + EntryBB->getTerminator()); new StoreInst(LSDA, LSDAFieldPtr, true, EntryBB->getTerminator()); return FuncCtx; @@ -464,7 +463,7 @@ bool SjLjEHPass::setupEntryBlockAndCallSites(Function &F) { // At this point, we are all set up, update the invoke instructions to mark // their call_site values. for (unsigned I = 0, E = Invokes.size(); I != E; ++I) { - insertCallSiteStore(Invokes[I], I + 1, CallSite); + insertCallSiteStore(Invokes[I], I + 1); ConstantInt *CallSiteNum = ConstantInt::get(Type::getInt32Ty(F.getContext()), I + 1); @@ -483,9 +482,9 @@ bool SjLjEHPass::setupEntryBlockAndCallSites(Function &F) { for (BasicBlock::iterator I = BB->begin(), end = BB->end(); I != end; ++I) if (CallInst *CI = dyn_cast(I)) { if (!CI->doesNotThrow()) - insertCallSiteStore(CI, -1, CallSite); + insertCallSiteStore(CI, -1); } else if (ResumeInst *RI = dyn_cast(I)) { - insertCallSiteStore(RI, -1, CallSite); + insertCallSiteStore(RI, -1); } // Register the function context and make sure it's known to not throw