forked from OSchip/llvm-project
96ab8726a3
Summary: Implements PR889 Removing the virtual table pointer from Value saves 1% of RSS when doing LTO of llc on Linux. The impact on time was positive, but too noisy to conclusively say that performance improved. Here is a link to the spreadsheet with the original data: https://docs.google.com/spreadsheets/d/1F4FHir0qYnV0MEp2sYYp_BuvnJgWlWPhWOwZ6LbW7W4/edit?usp=sharing This change makes it invalid to directly delete a Value, User, or Instruction pointer. Instead, such code can be rewritten to a null check and a call Value::deleteValue(). Value objects tend to have their lifetimes managed through iplist, so for the most part, this isn't a big deal. However, there are some places where LLVM deletes values, and those places had to be migrated to deleteValue. I have also created llvm::unique_value, which has a custom deleter, so it can be used in place of std::unique_ptr<Value>. I had to add the "DerivedUser" Deleter escape hatch for MemorySSA, which derives from User outside of lib/IR. Code in IR cannot include MemorySSA headers or call the MemoryAccess object destructors without introducing a circular dependency, so we need some level of indirection. Unfortunately, no class derived from User may have any virtual methods, because adding a virtual method would break User::getHungOffOperands(), which assumes that it can find the use list immediately prior to the User object. I've added a static_assert to the appropriate OperandTraits templates to help people avoid this trap. Reviewers: chandlerc, mehdi_amini, pete, dberlin, george.burgess.iv Reviewed By: chandlerc Subscribers: krytarowski, eraman, george.burgess.iv, mzolotukhin, Prazek, nlewycky, hans, inglorion, pcc, tejohnson, dberlin, llvm-commits Differential Revision: https://reviews.llvm.org/D31261 llvm-svn: 303362 |
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| .. | ||
| ASanStackFrameLayout.cpp | ||
| AddDiscriminators.cpp | ||
| BasicBlockUtils.cpp | ||
| BreakCriticalEdges.cpp | ||
| BuildLibCalls.cpp | ||
| BypassSlowDivision.cpp | ||
| CMakeLists.txt | ||
| CloneFunction.cpp | ||
| CloneModule.cpp | ||
| CmpInstAnalysis.cpp | ||
| CodeExtractor.cpp | ||
| CtorUtils.cpp | ||
| DemoteRegToStack.cpp | ||
| EscapeEnumerator.cpp | ||
| Evaluator.cpp | ||
| FlattenCFG.cpp | ||
| FunctionComparator.cpp | ||
| FunctionImportUtils.cpp | ||
| GlobalStatus.cpp | ||
| ImportedFunctionsInliningStatistics.cpp | ||
| InlineFunction.cpp | ||
| InstructionNamer.cpp | ||
| IntegerDivision.cpp | ||
| LCSSA.cpp | ||
| LLVMBuild.txt | ||
| LibCallsShrinkWrap.cpp | ||
| Local.cpp | ||
| LoopSimplify.cpp | ||
| LoopUnroll.cpp | ||
| LoopUnrollPeel.cpp | ||
| LoopUnrollRuntime.cpp | ||
| LoopUtils.cpp | ||
| LoopVersioning.cpp | ||
| LowerInvoke.cpp | ||
| LowerMemIntrinsics.cpp | ||
| LowerSwitch.cpp | ||
| Mem2Reg.cpp | ||
| MetaRenamer.cpp | ||
| ModuleUtils.cpp | ||
| NameAnonGlobals.cpp | ||
| PredicateInfo.cpp | ||
| PromoteMemoryToRegister.cpp | ||
| SSAUpdater.cpp | ||
| SanitizerStats.cpp | ||
| SimplifyCFG.cpp | ||
| SimplifyIndVar.cpp | ||
| SimplifyInstructions.cpp | ||
| SimplifyLibCalls.cpp | ||
| SplitModule.cpp | ||
| StripGCRelocates.cpp | ||
| StripNonLineTableDebugInfo.cpp | ||
| SymbolRewriter.cpp | ||
| UnifyFunctionExitNodes.cpp | ||
| Utils.cpp | ||
| VNCoercion.cpp | ||
| ValueMapper.cpp | ||