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LLVM
3.7.0
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Analysis pass providing branch probability information. More...
#include <BranchProbabilityInfo.h>
Public Member Functions | |
| BranchProbabilityInfo () | |
| void | getAnalysisUsage (AnalysisUsage &AU) const override |
| getAnalysisUsage - This function should be overriden by passes that need analysis information to do their job. More... | |
| bool | runOnFunction (Function &F) override |
| runOnFunction - Virtual method overriden by subclasses to do the per-function processing of the pass. More... | |
| void | releaseMemory () override |
| releaseMemory() - This member can be implemented by a pass if it wants to be able to release its memory when it is no longer needed. More... | |
| void | print (raw_ostream &OS, const Module *M=nullptr) const override |
| print - Print out the internal state of the pass. More... | |
| BranchProbability | getEdgeProbability (const BasicBlock *Src, unsigned IndexInSuccessors) const |
| Get an edge's probability, relative to other out-edges of the Src. More... | |
| BranchProbability | getEdgeProbability (const BasicBlock *Src, const BasicBlock *Dst) const |
| Get the probability of going from Src to Dst. More... | |
| bool | isEdgeHot (const BasicBlock *Src, const BasicBlock *Dst) const |
| Test if an edge is hot relative to other out-edges of the Src. More... | |
| BasicBlock * | getHotSucc (BasicBlock *BB) const |
| Retrieve the hot successor of a block if one exists. More... | |
| raw_ostream & | printEdgeProbability (raw_ostream &OS, const BasicBlock *Src, const BasicBlock *Dst) const |
| Print an edge's probability. More... | |
| uint32_t | getEdgeWeight (const BasicBlock *Src, unsigned IndexInSuccessors) const |
| Get the raw edge weight calculated for the edge. More... | |
| uint32_t | getEdgeWeight (const BasicBlock *Src, const BasicBlock *Dst) const |
| Get the raw edge weight calculated for the block pair. More... | |
| uint32_t | getEdgeWeight (const BasicBlock *Src, succ_const_iterator Dst) const |
| void | setEdgeWeight (const BasicBlock *Src, unsigned IndexInSuccessors, uint32_t Weight) |
| Set the raw edge weight for a given edge. More... | |
Public Member Functions inherited from llvm::FunctionPass | |
| FunctionPass (char &pid) | |
| Pass * | createPrinterPass (raw_ostream &O, const std::string &Banner) const override |
| createPrinterPass - Get a function printer pass. More... | |
| void | assignPassManager (PMStack &PMS, PassManagerType T) override |
| Find appropriate Function Pass Manager or Call Graph Pass Manager in the PM Stack and add self into that manager. More... | |
| PassManagerType | getPotentialPassManagerType () const override |
| Return what kind of Pass Manager can manage this pass. More... | |
Public Member Functions inherited from llvm::Pass | |
| Pass (PassKind K, char &pid) | |
| virtual | ~Pass () |
| PassKind | getPassKind () const |
| virtual const char * | getPassName () const |
| getPassName - Return a nice clean name for a pass. More... | |
| AnalysisID | getPassID () const |
| getPassID - Return the PassID number that corresponds to this pass. More... | |
| virtual bool | doInitialization (Module &) |
| doInitialization - Virtual method overridden by subclasses to do any necessary initialization before any pass is run. More... | |
| virtual bool | doFinalization (Module &) |
| doFinalization - Virtual method overriden by subclasses to do any necessary clean up after all passes have run. More... | |
| void | dump () const |
| virtual void | preparePassManager (PMStack &) |
| Check if available pass managers are suitable for this pass or not. More... | |
| void | setResolver (AnalysisResolver *AR) |
| AnalysisResolver * | getResolver () const |
| virtual void * | getAdjustedAnalysisPointer (AnalysisID ID) |
| getAdjustedAnalysisPointer - This method is used when a pass implements an analysis interface through multiple inheritance. More... | |
| virtual ImmutablePass * | getAsImmutablePass () |
| virtual PMDataManager * | getAsPMDataManager () |
| virtual void | verifyAnalysis () const |
| verifyAnalysis() - This member can be implemented by a analysis pass to check state of analysis information. More... | |
| virtual void | dumpPassStructure (unsigned Offset=0) |
| template<typename AnalysisType > | |
| AnalysisType * | getAnalysisIfAvailable () const |
| getAnalysisIfAvailable<AnalysisType>() - Subclasses use this function to get analysis information that might be around, for example to update it. More... | |
| bool | mustPreserveAnalysisID (char &AID) const |
| mustPreserveAnalysisID - This method serves the same function as getAnalysisIfAvailable, but works if you just have an AnalysisID. More... | |
| template<typename AnalysisType > | |
| AnalysisType & | getAnalysis () const |
| getAnalysis<AnalysisType>() - This function is used by subclasses to get to the analysis information that they claim to use by overriding the getAnalysisUsage function. More... | |
| template<typename AnalysisType > | |
| AnalysisType & | getAnalysis (Function &F) |
| getAnalysis<AnalysisType>() - This function is used by subclasses to get to the analysis information that they claim to use by overriding the getAnalysisUsage function. More... | |
| template<typename AnalysisType > | |
| AnalysisType & | getAnalysisID (AnalysisID PI) const |
| template<typename AnalysisType > | |
| AnalysisType & | getAnalysisID (AnalysisID PI, Function &F) |
Static Public Member Functions | |
| static uint32_t | getBranchWeightStackProtector (bool IsLikely) |
Static Public Member Functions inherited from llvm::Pass | |
| static const PassInfo * | lookupPassInfo (const void *TI) |
| static const PassInfo * | lookupPassInfo (StringRef Arg) |
| static Pass * | createPass (AnalysisID ID) |
Static Public Attributes | |
| static char | ID = 0 |
Additional Inherited Members | |
Protected Member Functions inherited from llvm::FunctionPass | |
| bool | skipOptnoneFunction (const Function &F) const |
| skipOptnoneFunction - This function has Attribute::OptimizeNone and most transformation passes should skip it. More... | |
Analysis pass providing branch probability information.
This is a function analysis pass which provides information on the relative probabilities of each "edge" in the function's CFG where such an edge is defined by a pair (PredBlock and an index in the successors). The probability of an edge from one block is always relative to the probabilities of other edges from the block. The probabilites of all edges from a block sum to exactly one (100%). We use a pair (PredBlock and an index in the successors) to uniquely identify an edge, since we can have multiple edges from Src to Dst. As an example, we can have a switch which jumps to Dst with value 0 and value 10.
Definition at line 40 of file BranchProbabilityInfo.h.
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inline |
Definition at line 44 of file BranchProbabilityInfo.h.
References llvm::PassRegistry::getPassRegistry(), and llvm::initializeBranchProbabilityInfoPass().
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overridevirtual |
getAnalysisUsage - This function should be overriden by passes that need analysis information to do their job.
If a pass specifies that it uses a particular analysis result to this function, it can then use the getAnalysis<AnalysisType>() function, below.
Reimplemented from llvm::Pass.
Definition at line 507 of file BranchProbabilityInfo.cpp.
References llvm::AnalysisUsage::addRequired(), and llvm::AnalysisUsage::setPreservesAll().
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inlinestatic |
Definition at line 117 of file BranchProbabilityInfo.h.
| BranchProbability BranchProbabilityInfo::getEdgeProbability | ( | const BasicBlock * | Src, |
| unsigned | IndexInSuccessors | ||
| ) | const |
Get an edge's probability, relative to other out-edges of the Src.
Get an edge's probability, relative to other out-edges from Src.
This routine provides access to the fractional probability between zero (0%) and one (100%) of this edge executing, relative to other edges leaving the 'Src' block. The returned probability is never zero, and can only be one if the source block has only one successor.
Definition at line 661 of file BranchProbabilityInfo.cpp.
References getEdgeWeight(), and N.
Referenced by isEdgeHot(), and printEdgeProbability().
| BranchProbability BranchProbabilityInfo::getEdgeProbability | ( | const BasicBlock * | Src, |
| const BasicBlock * | Dst | ||
| ) | const |
Get the probability of going from Src to Dst.
It returns the sum of all probabilities for edges from Src to Dst.
Definition at line 671 of file BranchProbabilityInfo.cpp.
References getEdgeWeight(), and N.
| uint32_t BranchProbabilityInfo::getEdgeWeight | ( | const BasicBlock * | Src, |
| unsigned | IndexInSuccessors | ||
| ) | const |
Get the raw edge weight calculated for the edge.
Get the raw edge weight for the edge.
This returns the raw edge weight. It is guaranteed to fall between 1 and UINT32_MAX. Note that the raw edge weight is not meaningful in isolation. This interface should be very carefully, and primarily by routines that are updating the analysis by later calling setEdgeWeight.
If can't find it, return DEFAULT_WEIGHT value. Here an edge is specified using PredBlock and an index to the successors.
Definition at line 615 of file BranchProbabilityInfo.cpp.
References llvm::SmallVectorTemplateCommon< T >::end(), and I.
Referenced by llvm::FastISel::fastEmitBranch(), getEdgeProbability(), getEdgeWeight(), and getHotSucc().
| uint32_t BranchProbabilityInfo::getEdgeWeight | ( | const BasicBlock * | Src, |
| const BasicBlock * | Dst | ||
| ) | const |
Get the raw edge weight calculated for the block pair.
This returns the sum of all raw edge weights from Src to Dst. It is guaranteed to fall between 1 and UINT32_MAX.
This returns the sum of all raw edge weights from Src to Dst.
Definition at line 633 of file BranchProbabilityInfo.cpp.
References llvm::SmallVectorTemplateCommon< T >::end(), I, llvm::succ_begin(), and llvm::succ_end().
| uint32_t BranchProbabilityInfo::getEdgeWeight | ( | const BasicBlock * | Src, |
| succ_const_iterator | Dst | ||
| ) | const |
Definition at line 625 of file BranchProbabilityInfo.cpp.
References getEdgeWeight(), and llvm::SuccIterator< Term_, BB_ >::getSuccessorIndex().
| BasicBlock * BranchProbabilityInfo::getHotSucc | ( | BasicBlock * | BB | ) | const |
Retrieve the hot successor of a block if one exists.
Given a basic block, look through its successors and if one exists for which
Definition at line 585 of file BranchProbabilityInfo.cpp.
References getEdgeWeight(), I, llvm::succ_begin(), and llvm::succ_end().
| bool BranchProbabilityInfo::isEdgeHot | ( | const BasicBlock * | Src, |
| const BasicBlock * | Dst | ||
| ) | const |
Test if an edge is hot relative to other out-edges of the Src.
Check whether this edge out of the source block is 'hot'. We define hot as having a relative probability >= 80%.
Definition at line 579 of file BranchProbabilityInfo.cpp.
References getEdgeProbability().
Referenced by printEdgeProbability().
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overridevirtual |
print - Print out the internal state of the pass.
This is called by Analyze to print out the contents of an analysis. Otherwise it is not necessary to implement this method. Beware that the module pointer MAY be null. This automatically forwards to a virtual function that does not provide the Module* in case the analysis doesn't need it it can just be ignored.
Reimplemented from llvm::Pass.
Definition at line 550 of file BranchProbabilityInfo.cpp.
References llvm::Function::begin(), llvm::Function::end(), printEdgeProbability(), llvm::SI, llvm::succ_begin(), and llvm::succ_end().
| raw_ostream & BranchProbabilityInfo::printEdgeProbability | ( | raw_ostream & | OS, |
| const BasicBlock * | Src, | ||
| const BasicBlock * | Dst | ||
| ) | const |
Print an edge's probability.
Retrieves an edge's probability similarly to
Definition at line 680 of file BranchProbabilityInfo.cpp.
References getEdgeProbability(), llvm::Value::getName(), and isEdgeHot().
Referenced by print().
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overridevirtual |
releaseMemory() - This member can be implemented by a pass if it wants to be able to release its memory when it is no longer needed.
The default behavior of passes is to hold onto memory for the entire duration of their lifetime (which is the entire compile time). For pipelined passes, this is not a big deal because that memory gets recycled every time the pass is invoked on another program unit. For IP passes, it is more important to free memory when it is unused.
Optionally implement this function to release pass memory when it is no longer used.
Reimplemented from llvm::Pass.
Definition at line 546 of file BranchProbabilityInfo.cpp.
References llvm::SmallVectorImpl< T >::clear().
runOnFunction - Virtual method overriden by subclasses to do the per-function processing of the pass.
Implements llvm::FunctionPass.
Definition at line 512 of file BranchProbabilityInfo.cpp.
References llvm::dbgs(), DEBUG, F(), llvm::Function::getEntryBlock(), llvm::Value::getName(), and llvm::post_order().
| void BranchProbabilityInfo::setEdgeWeight | ( | const BasicBlock * | Src, |
| unsigned | IndexInSuccessors, | ||
| uint32_t | Weight | ||
| ) |
Set the raw edge weight for a given edge.
Set the edge weight for a given edge specified by PredBlock and an index to the successors.
This allows a pass to explicitly set the edge weight for an edge. It can be used when updating the CFG to update and preserve the branch probability information. Read the implementation of how these edge weights are calculated carefully before using!
Definition at line 651 of file BranchProbabilityInfo.cpp.
References llvm::dbgs(), DEBUG, and llvm::Value::getName().
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static |
Definition at line 42 of file BranchProbabilityInfo.h.
1.8.6