diff options
| -rw-r--r-- | llvm/lib/CodeGen/GCRootLowering.cpp | 91 |
1 files changed, 45 insertions, 46 deletions
diff --git a/llvm/lib/CodeGen/GCRootLowering.cpp b/llvm/lib/CodeGen/GCRootLowering.cpp index 10da4003684..9907a302253 100644 --- a/llvm/lib/CodeGen/GCRootLowering.cpp +++ b/llvm/lib/CodeGen/GCRootLowering.cpp @@ -38,12 +38,7 @@ namespace { /// directed by the GCStrategy. It also performs automatic root initialization /// and custom intrinsic lowering. class LowerIntrinsics : public FunctionPass { - static bool NeedsDefaultLoweringPass(const GCStrategy &C); - static bool NeedsCustomLoweringPass(const GCStrategy &C); - static bool CouldBecomeSafePoint(Instruction *I); bool PerformDefaultLowering(Function &F, GCStrategy &Coll); - static bool InsertRootInitializers(Function &F, AllocaInst **Roots, - unsigned Count); public: static char ID; @@ -108,6 +103,20 @@ void LowerIntrinsics::getAnalysisUsage(AnalysisUsage &AU) const { AU.addPreserved<DominatorTreeWrapperPass>(); } +static bool NeedsDefaultLoweringPass(const GCStrategy &C) { + // Default lowering is necessary only if read or write barriers have a default + // action. The default for roots is no action. + return !C.customWriteBarrier() || !C.customReadBarrier() || + C.initializeRoots(); +} + +static bool NeedsCustomLoweringPass(const GCStrategy &C) { + // Custom lowering is only necessary if enabled for some action. + return C.customWriteBarrier() || C.customReadBarrier() || C.customRoots(); +} + + + /// doInitialization - If this module uses the GC intrinsics, find them now. bool LowerIntrinsics::doInitialization(Module &M) { // FIXME: This is rather antisocial in the context of a JIT since it performs @@ -129,8 +138,37 @@ bool LowerIntrinsics::doInitialization(Module &M) { return MadeChange; } -bool LowerIntrinsics::InsertRootInitializers(Function &F, AllocaInst **Roots, - unsigned Count) { + +/// CouldBecomeSafePoint - Predicate to conservatively determine whether the +/// instruction could introduce a safe point. +static bool CouldBecomeSafePoint(Instruction *I) { + // The natural definition of instructions which could introduce safe points + // are: + // + // - call, invoke (AfterCall, BeforeCall) + // - phis (Loops) + // - invoke, ret, unwind (Exit) + // + // However, instructions as seemingly inoccuous as arithmetic can become + // libcalls upon lowering (e.g., div i64 on a 32-bit platform), so instead + // it is necessary to take a conservative approach. + + if (isa<AllocaInst>(I) || isa<GetElementPtrInst>(I) || isa<StoreInst>(I) || + isa<LoadInst>(I)) + return false; + + // llvm.gcroot is safe because it doesn't do anything at runtime. + if (CallInst *CI = dyn_cast<CallInst>(I)) + if (Function *F = CI->getCalledFunction()) + if (unsigned IID = F->getIntrinsicID()) + if (IID == Intrinsic::gcroot) + return false; + + return true; +} + +static bool InsertRootInitializers(Function &F, AllocaInst **Roots, + unsigned Count) { // Scroll past alloca instructions. BasicBlock::iterator IP = F.getEntryBlock().begin(); while (isa<AllocaInst>(IP)) @@ -160,45 +198,6 @@ bool LowerIntrinsics::InsertRootInitializers(Function &F, AllocaInst **Roots, return MadeChange; } -bool LowerIntrinsics::NeedsDefaultLoweringPass(const GCStrategy &C) { - // Default lowering is necessary only if read or write barriers have a default - // action. The default for roots is no action. - return !C.customWriteBarrier() || !C.customReadBarrier() || - C.initializeRoots(); -} - -bool LowerIntrinsics::NeedsCustomLoweringPass(const GCStrategy &C) { - // Custom lowering is only necessary if enabled for some action. - return C.customWriteBarrier() || C.customReadBarrier() || C.customRoots(); -} - -/// CouldBecomeSafePoint - Predicate to conservatively determine whether the -/// instruction could introduce a safe point. -bool LowerIntrinsics::CouldBecomeSafePoint(Instruction *I) { - // The natural definition of instructions which could introduce safe points - // are: - // - // - call, invoke (AfterCall, BeforeCall) - // - phis (Loops) - // - invoke, ret, unwind (Exit) - // - // However, instructions as seemingly inoccuous as arithmetic can become - // libcalls upon lowering (e.g., div i64 on a 32-bit platform), so instead - // it is necessary to take a conservative approach. - - if (isa<AllocaInst>(I) || isa<GetElementPtrInst>(I) || isa<StoreInst>(I) || - isa<LoadInst>(I)) - return false; - - // llvm.gcroot is safe because it doesn't do anything at runtime. - if (CallInst *CI = dyn_cast<CallInst>(I)) - if (Function *F = CI->getCalledFunction()) - if (unsigned IID = F->getIntrinsicID()) - if (IID == Intrinsic::gcroot) - return false; - - return true; -} /// runOnFunction - Replace gcread/gcwrite intrinsics with loads and stores. /// Leave gcroot intrinsics; the code generator needs to see those. |
