diff options
| -rw-r--r-- | include/llvm/Analysis/CodeMetrics.h | 66 | ||||
| -rw-r--r-- | lib/Analysis/CMakeLists.txt | 1 | ||||
| -rw-r--r-- | lib/Analysis/CodeMetrics.cpp | 176 | ||||
| -rw-r--r-- | lib/Analysis/InlineCost.cpp | 158 |
4 files changed, 209 insertions, 192 deletions
diff --git a/include/llvm/Analysis/CodeMetrics.h b/include/llvm/Analysis/CodeMetrics.h index cf92642d2f..033e19bc7f 100644 --- a/include/llvm/Analysis/CodeMetrics.h +++ b/include/llvm/Analysis/CodeMetrics.h @@ -1,4 +1,4 @@ -//===- CodeMetrics.h - Measures the weight of a function---------*- C++ -*-===// +//===- CodeMetrics.h - Code cost measurements -------------------*- C++ -*-===// // // The LLVM Compiler Infrastructure // @@ -18,53 +18,58 @@ #include "llvm/ADT/DenseMap.h" namespace llvm { - class BasicBlock; class Function; class TargetData; class Value; - // CodeMetrics - Calculate size and a few similar metrics for a set of - // basic blocks. - struct CodeMetrics { - /// NeverInline - True if this callee should never be inlined into a - /// caller. - // bool NeverInline; + /// \brief Check whether a call will lower to something small. + /// + /// This tests checks whether calls to this function will lower to something + /// significantly cheaper than a traditional call, often a single + /// instruction. + bool callIsSmall(const Function *F); - // True if this function contains a call to setjmp or other functions - // with attribute "returns twice" without having the attribute itself. + /// \brief Utility to calculate the size and a few similar metrics for a set + /// of basic blocks. + struct CodeMetrics { + /// \brief True if this function contains a call to setjmp or other functions + /// with attribute "returns twice" without having the attribute itself. bool exposesReturnsTwice; - // True if this function calls itself + /// \brief True if this function calls itself. bool isRecursive; - // True if this function contains one or more indirect branches + /// \brief True if this function contains one or more indirect branches. bool containsIndirectBr; - /// usesDynamicAlloca - True if this function calls alloca (in the C sense). + /// \brief True if this function calls alloca (in the C sense). bool usesDynamicAlloca; - /// NumInsts, NumBlocks - Keep track of how large each function is, which - /// is used to estimate the code size cost of inlining it. - unsigned NumInsts, NumBlocks; + /// \brief Number of instructions in the analyzed blocks. + unsigned NumInsts; - /// NumBBInsts - Keeps track of basic block code size estimates. + /// \brief Number of analyzed blocks. + unsigned NumBlocks; + + /// \brief Keeps track of basic block code size estimates. DenseMap<const BasicBlock *, unsigned> NumBBInsts; - /// NumCalls - Keep track of the number of calls to 'big' functions. + /// \brief Keep track of the number of calls to 'big' functions. unsigned NumCalls; - /// NumInlineCandidates - Keep track of the number of calls to internal - /// functions with only a single caller. These are likely targets for - /// future inlining, likely exposed by interleaved devirtualization. + /// \brief The number of calls to internal functions with a single caller. + /// + /// These are likely targets for future inlining, likely exposed by + /// interleaved devirtualization. unsigned NumInlineCandidates; - /// NumVectorInsts - Keep track of how many instructions produce vector - /// values. The inliner is being more aggressive with inlining vector - /// kernels. + /// \brief How many instructions produce vector values. + /// + /// The inliner is more aggressive with inlining vector kernels. unsigned NumVectorInsts; - /// NumRets - Keep track of how many Ret instructions the block contains. + /// \brief How many 'ret' instructions the blocks contain. unsigned NumRets; CodeMetrics() : exposesReturnsTwice(false), isRecursive(false), @@ -73,18 +78,11 @@ namespace llvm { NumInlineCandidates(0), NumVectorInsts(0), NumRets(0) {} - /// analyzeBasicBlock - Add information about the specified basic block - /// to the current structure. + /// \brief Add information about a block to the current state. void analyzeBasicBlock(const BasicBlock *BB, const TargetData *TD = 0); - /// analyzeFunction - Add information about the specified function - /// to the current structure. + /// \brief Add information about a function to the current state. void analyzeFunction(Function *F, const TargetData *TD = 0); - - /// CountBonusForConstant - Figure out an approximation for how much - /// per-call performance boost we can expect if the specified value is - /// constant. - unsigned CountBonusForConstant(Value *V); }; } diff --git a/lib/Analysis/CMakeLists.txt b/lib/Analysis/CMakeLists.txt index cb1e1ebbd1..2e3ec8bebc 100644 --- a/lib/Analysis/CMakeLists.txt +++ b/lib/Analysis/CMakeLists.txt @@ -10,6 +10,7 @@ add_llvm_library(LLVMAnalysis BranchProbabilityInfo.cpp CFGPrinter.cpp CaptureTracking.cpp + CodeMetrics.cpp ConstantFolding.cpp DIBuilder.cpp DbgInfoPrinter.cpp diff --git a/lib/Analysis/CodeMetrics.cpp b/lib/Analysis/CodeMetrics.cpp new file mode 100644 index 0000000000..6c93f78629 --- /dev/null +++ b/lib/Analysis/CodeMetrics.cpp @@ -0,0 +1,176 @@ +//===- CodeMetrics.cpp - Code cost measurements ---------------------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file implements code cost measurement utilities. +// +//===----------------------------------------------------------------------===// + +#include "llvm/Analysis/CodeMetrics.h" +#include "llvm/Function.h" +#include "llvm/Support/CallSite.h" +#include "llvm/IntrinsicInst.h" +#include "llvm/Target/TargetData.h" + +using namespace llvm; + +/// callIsSmall - If a call is likely to lower to a single target instruction, +/// or is otherwise deemed small return true. +/// TODO: Perhaps calls like memcpy, strcpy, etc? +bool llvm::callIsSmall(const Function *F) { + if (!F) return false; + + if (F->hasLocalLinkage()) return false; + + if (!F->hasName()) return false; + + StringRef Name = F->getName(); + + // These will all likely lower to a single selection DAG node. + if (Name == "copysign" || Name == "copysignf" || Name == "copysignl" || + Name == "fabs" || Name == "fabsf" || Name == "fabsl" || + Name == "sin" || Name == "sinf" || Name == "sinl" || + Name == "cos" || Name == "cosf" || Name == "cosl" || + Name == "sqrt" || Name == "sqrtf" || Name == "sqrtl" ) + return true; + + // These are all likely to be optimized into something smaller. + if (Name == "pow" || Name == "powf" || Name == "powl" || + Name == "exp2" || Name == "exp2l" || Name == "exp2f" || + Name == "floor" || Name == "floorf" || Name == "ceil" || + Name == "round" || Name == "ffs" || Name == "ffsl" || + Name == "abs" || Name == "labs" || Name == "llabs") + return true; + + return false; +} + +/// analyzeBasicBlock - Fill in the current structure with information gleaned +/// from the specified block. +void CodeMetrics::analyzeBasicBlock(const BasicBlock *BB, + const TargetData *TD) { + ++NumBlocks; + unsigned NumInstsBeforeThisBB = NumInsts; + for (BasicBlock::const_iterator II = BB->begin(), E = BB->end(); + II != E; ++II) { + if (isa<PHINode>(II)) continue; // PHI nodes don't count. + + // Special handling for calls. + if (isa<CallInst>(II) || isa<InvokeInst>(II)) { + if (const IntrinsicInst *IntrinsicI = dyn_cast<IntrinsicInst>(II)) { + switch (IntrinsicI->getIntrinsicID()) { + default: break; + case Intrinsic::dbg_declare: + case Intrinsic::dbg_value: + case Intrinsic::invariant_start: + case Intrinsic::invariant_end: + case Intrinsic::lifetime_start: + case Intrinsic::lifetime_end: + case Intrinsic::objectsize: + case Intrinsic::ptr_annotation: + case Intrinsic::var_annotation: + // These intrinsics don't count as size. + continue; + } + } + + ImmutableCallSite CS(cast<Instruction>(II)); + + if (const Function *F = CS.getCalledFunction()) { + // If a function is both internal and has a single use, then it is + // extremely likely to get inlined in the future (it was probably + // exposed by an interleaved devirtualization pass). + if (!CS.isNoInline() && F->hasInternalLinkage() && F->hasOneUse()) + ++NumInlineCandidates; + + // If this call is to function itself, then the function is recursive. + // Inlining it into other functions is a bad idea, because this is + // basically just a form of loop peeling, and our metrics aren't useful + // for that case. + if (F == BB->getParent()) + isRecursive = true; + } + + if (!isa<IntrinsicInst>(II) && !callIsSmall(CS.getCalledFunction())) { + // Each argument to a call takes on average one instruction to set up. + NumInsts += CS.arg_size(); + + // We don't want inline asm to count as a call - that would prevent loop + // unrolling. The argument setup cost is still real, though. + if (!isa<InlineAsm>(CS.getCalledValue())) + ++NumCalls; + } + } + + if (const AllocaInst *AI = dyn_cast<AllocaInst>(II)) { + if (!AI->isStaticAlloca()) + this->usesDynamicAlloca = true; + } + + if (isa<ExtractElementInst>(II) || II->getType()->isVectorTy()) + ++NumVectorInsts; + + if (const CastInst *CI = dyn_cast<CastInst>(II)) { + // Noop casts, including ptr <-> int, don't count. + if (CI->isLosslessCast() || isa<IntToPtrInst>(CI) || + isa<PtrToIntInst>(CI)) + continue; + // trunc to a native type is free (assuming the target has compare and + // shift-right of the same width). + if (isa<TruncInst>(CI) && TD && + TD->isLegalInteger(TD->getTypeSizeInBits(CI->getType()))) + continue; + // Result of a cmp instruction is often extended (to be used by other + // cmp instructions, logical or return instructions). These are usually + // nop on most sane targets. + if (isa<CmpInst>(CI->getOperand(0))) + continue; + } else if (const GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(II)){ + // If a GEP has all constant indices, it will probably be folded with + // a load/store. + if (GEPI->hasAllConstantIndices()) + continue; + } + + ++NumInsts; + } + + if (isa<ReturnInst>(BB->getTerminator())) + ++NumRets; + + // We never want to inline functions that contain an indirectbr. This is + // incorrect because all the blockaddress's (in static global initializers + // for example) would be referring to the original function, and this indirect + // jump would jump from the inlined copy of the function into the original + // function which is extremely undefined behavior. + // FIXME: This logic isn't really right; we can safely inline functions + // with indirectbr's as long as no other function or global references the + // blockaddress of a block within the current function. And as a QOI issue, + // if someone is using a blockaddress without an indirectbr, and that + // reference somehow ends up in another function or global, we probably + // don't want to inline this function. + if (isa<IndirectBrInst>(BB->getTerminator())) + containsIndirectBr = true; + + // Remember NumInsts for this BB. + NumBBInsts[BB] = NumInsts - NumInstsBeforeThisBB; +} + +void CodeMetrics::analyzeFunction(Function *F, const TargetData *TD) { + // If this function contains a call that "returns twice" (e.g., setjmp or + // _setjmp) and it isn't marked with "returns twice" itself, never inline it. + // This is a hack because we depend on the user marking their local variables + // as volatile if they are live across a setjmp call, and they probably + // won't do this in callers. + exposesReturnsTwice = F->callsFunctionThatReturnsTwice() && + !F->hasFnAttr(Attribute::ReturnsTwice); + + // Look at the size of the callee. + for (Function::const_iterator BB = F->begin(), E = F->end(); BB != E; ++BB) + analyzeBasicBlock(&*BB, TD); +} diff --git a/lib/Analysis/InlineCost.cpp b/lib/Analysis/InlineCost.cpp index 3754e923ce..e08ff92618 100644 --- a/lib/Analysis/InlineCost.cpp +++ b/lib/Analysis/InlineCost.cpp @@ -20,148 +20,6 @@ using namespace llvm; -/// callIsSmall - If a call is likely to lower to a single target instruction, -/// or is otherwise deemed small return true. -/// TODO: Perhaps calls like memcpy, strcpy, etc? -bool llvm::callIsSmall(const Function *F) { - if (!F) return false; - - if (F->hasLocalLinkage()) return false; - - if (!F->hasName()) return false; - - StringRef Name = F->getName(); - - // These will all likely lower to a single selection DAG node. - if (Name == "copysign" || Name == "copysignf" || Name == "copysignl" || - Name == "fabs" || Name == "fabsf" || Name == "fabsl" || - Name == "sin" || Name == "sinf" || Name == "sinl" || - Name == "cos" || Name == "cosf" || Name == "cosl" || - Name == "sqrt" || Name == "sqrtf" || Name == "sqrtl" ) - return true; - - // These are all likely to be optimized into something smaller. - if (Name == "pow" || Name == "powf" || Name == "powl" || - Name == "exp2" || Name == "exp2l" || Name == "exp2f" || - Name == "floor" || Name == "floorf" || Name == "ceil" || - Name == "round" || Name == "ffs" || Name == "ffsl" || - Name == "abs" || Name == "labs" || Name == "llabs") - return true; - - return false; -} - -/// analyzeBasicBlock - Fill in the current structure with information gleaned -/// from the specified block. -void CodeMetrics::analyzeBasicBlock(const BasicBlock *BB, - const TargetData *TD) { - ++NumBlocks; - unsigned NumInstsBeforeThisBB = NumInsts; - for (BasicBlock::const_iterator II = BB->begin(), E = BB->end(); - II != E; ++II) { - if (isa<PHINode>(II)) continue; // PHI nodes don't count. - - // Special handling for calls. - if (isa<CallInst>(II) || isa<InvokeInst>(II)) { - if (const IntrinsicInst *IntrinsicI = dyn_cast<IntrinsicInst>(II)) { - switch (IntrinsicI->getIntrinsicID()) { - default: break; - case Intrinsic::dbg_declare: - case Intrinsic::dbg_value: - case Intrinsic::invariant_start: - case Intrinsic::invariant_end: - case Intrinsic::lifetime_start: - case Intrinsic::lifetime_end: - case Intrinsic::objectsize: - case Intrinsic::ptr_annotation: - case Intrinsic::var_annotation: - // These intrinsics don't count as size. - continue; - } - } - - ImmutableCallSite CS(cast<Instruction>(II)); - - if (const Function *F = CS.getCalledFunction()) { - // If a function is both internal and has a single use, then it is - // extremely likely to get inlined in the future (it was probably - // exposed by an interleaved devirtualization pass). - if (!CS.isNoInline() && F->hasInternalLinkage() && F->hasOneUse()) - ++NumInlineCandidates; - - // If this call is to function itself, then the function is recursive. - // Inlining it into other functions is a bad idea, because this is - // basically just a form of loop peeling, and our metrics aren't useful - // for that case. - if (F == BB->getParent()) - isRecursive = true; - } - - if (!isa<IntrinsicInst>(II) && !callIsSmall(CS.getCalledFunction())) { - // Each argument to a call takes on average one instruction to set up. - NumInsts += CS.arg_size(); - - // We don't want inline asm to count as a call - that would prevent loop - // unrolling. The argument setup cost is still real, though. - if (!isa<InlineAsm>(CS.getCalledValue())) - ++NumCalls; - } - } - - if (const AllocaInst *AI = dyn_cast<AllocaInst>(II)) { - if (!AI->isStaticAlloca()) - this->usesDynamicAlloca = true; - } - - if (isa<ExtractElementInst>(II) || II->getType()->isVectorTy()) - ++NumVectorInsts; - - if (const CastInst *CI = dyn_cast<CastInst>(II)) { - // Noop casts, including ptr <-> int, don't count. - if (CI->isLosslessCast() || isa<IntToPtrInst>(CI) || - isa<PtrToIntInst>(CI)) - continue; - // trunc to a native type is free (assuming the target has compare and - // shift-right of the same width). - if (isa<TruncInst>(CI) && TD && - TD->isLegalInteger(TD->getTypeSizeInBits(CI->getType()))) - continue; - // Result of a cmp instruction is often extended (to be used by other - // cmp instructions, logical or return instructions). These are usually - // nop on most sane targets. - if (isa<CmpInst>(CI->getOperand(0))) - continue; - } else if (const GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(II)){ - // If a GEP has all constant indices, it will probably be folded with - // a load/store. - if (GEPI->hasAllConstantIndices()) - continue; - } - - ++NumInsts; - } - - if (isa<ReturnInst>(BB->getTerminator())) - ++NumRets; - - // We never want to inline functions that contain an indirectbr. This is - // incorrect because all the blockaddress's (in static global initializers - // for example) would be referring to the original function, and this indirect - // jump would jump from the inlined copy of the function into the original - // function which is extremely undefined behavior. - // FIXME: This logic isn't really right; we can safely inline functions - // with indirectbr's as long as no other function or global references the - // blockaddress of a block within the current function. And as a QOI issue, - // if someone is using a blockaddress without an indirectbr, and that - // reference somehow ends up in another function or global, we probably - // don't want to inline this function. - if (isa<IndirectBrInst>(BB->getTerminator())) - containsIndirectBr = true; - - // Remember NumInsts for this BB. - NumBBInsts[BB] = NumInsts - NumInstsBeforeThisBB; -} - unsigned InlineCostAnalyzer::FunctionInfo::countCodeReductionForConstant( const CodeMetrics &Metrics, Value *V) { unsigned Reduction = 0; @@ -446,22 +304,6 @@ void InlineCostAnalyzer::FunctionInfo::countCodeReductionForPointerPair( /// analyzeFunction - Fill in the current structure with information gleaned /// from the specified function. -void CodeMetrics::analyzeFunction(Function *F, const TargetData *TD) { - // If this function contains a call that "returns twice" (e.g., setjmp or - // _setjmp) and it isn't marked with "returns twice" itself, never inline it. - // This is a hack because we depend on the user marking their local variables - // as volatile if they are live across a setjmp call, and they probably - // won't do this in callers. - exposesReturnsTwice = F->callsFunctionThatReturnsTwice() && - !F->hasFnAttr(Attribute::ReturnsTwice); - - // Look at the size of the callee. - for (Function::const_iterator BB = F->begin(), E = F->end(); BB != E; ++BB) - analyzeBasicBlock(&*BB, TD); -} - -/// analyzeFunction - Fill in the current structure with information gleaned -/// from the specified function. void InlineCostAnalyzer::FunctionInfo::analyzeFunction(Function *F, const TargetData *TD) { Metrics.analyzeFunction(F, TD); |