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| author | 2020-08-03 15:06:44 +0000 | |
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| committer | 2020-08-03 15:06:44 +0000 | |
| commit | b64793999546ed8adebaeebd9d8345d18db8927d (patch) | |
| tree | 4357c27b561d73b0e089727c6ed659f2ceff5f47 /gnu/llvm/lib/CodeGen/SpillPlacement.h | |
| parent | Add support for UTF-8 DISPLAY-HINTs with octet length. For now only (diff) | |
| download | wireguard-openbsd-b64793999546ed8adebaeebd9d8345d18db8927d.tar.xz wireguard-openbsd-b64793999546ed8adebaeebd9d8345d18db8927d.zip | |
Remove LLVM 8.0.1 files.
Diffstat (limited to 'gnu/llvm/lib/CodeGen/SpillPlacement.h')
| -rw-r--r-- | gnu/llvm/lib/CodeGen/SpillPlacement.h | 170 |
1 files changed, 0 insertions, 170 deletions
diff --git a/gnu/llvm/lib/CodeGen/SpillPlacement.h b/gnu/llvm/lib/CodeGen/SpillPlacement.h deleted file mode 100644 index aa3ac444e0d..00000000000 --- a/gnu/llvm/lib/CodeGen/SpillPlacement.h +++ /dev/null @@ -1,170 +0,0 @@ -//===- SpillPlacement.h - Optimal Spill Code Placement ---------*- C++ -*--===// -// -// The LLVM Compiler Infrastructure -// -// This file is distributed under the University of Illinois Open Source -// License. See LICENSE.TXT for details. -// -//===----------------------------------------------------------------------===// -// -// This analysis computes the optimal spill code placement between basic blocks. -// -// The runOnMachineFunction() method only precomputes some profiling information -// about the CFG. The real work is done by prepare(), addConstraints(), and -// finish() which are called by the register allocator. -// -// Given a variable that is live across multiple basic blocks, and given -// constraints on the basic blocks where the variable is live, determine which -// edge bundles should have the variable in a register and which edge bundles -// should have the variable in a stack slot. -// -// The returned bit vector can be used to place optimal spill code at basic -// block entries and exits. Spill code placement inside a basic block is not -// considered. -// -//===----------------------------------------------------------------------===// - -#ifndef LLVM_LIB_CODEGEN_SPILLPLACEMENT_H -#define LLVM_LIB_CODEGEN_SPILLPLACEMENT_H - -#include "llvm/ADT/ArrayRef.h" -#include "llvm/ADT/SmallVector.h" -#include "llvm/ADT/SparseSet.h" -#include "llvm/CodeGen/MachineFunctionPass.h" -#include "llvm/Support/BlockFrequency.h" - -namespace llvm { - -class BitVector; -class EdgeBundles; -class MachineBlockFrequencyInfo; -class MachineFunction; -class MachineLoopInfo; - -class SpillPlacement : public MachineFunctionPass { - struct Node; - const MachineFunction *MF; - const EdgeBundles *bundles; - const MachineLoopInfo *loops; - const MachineBlockFrequencyInfo *MBFI; - Node *nodes = nullptr; - - // Nodes that are active in the current computation. Owned by the prepare() - // caller. - BitVector *ActiveNodes; - - // Nodes with active links. Populated by scanActiveBundles. - SmallVector<unsigned, 8> Linked; - - // Nodes that went positive during the last call to scanActiveBundles or - // iterate. - SmallVector<unsigned, 8> RecentPositive; - - // Block frequencies are computed once. Indexed by block number. - SmallVector<BlockFrequency, 8> BlockFrequencies; - - /// Decision threshold. A node gets the output value 0 if the weighted sum of - /// its inputs falls in the open interval (-Threshold;Threshold). - BlockFrequency Threshold; - - /// List of nodes that need to be updated in ::iterate. - SparseSet<unsigned> TodoList; - -public: - static char ID; // Pass identification, replacement for typeid. - - SpillPlacement() : MachineFunctionPass(ID) {} - ~SpillPlacement() override { releaseMemory(); } - - /// BorderConstraint - A basic block has separate constraints for entry and - /// exit. - enum BorderConstraint { - DontCare, ///< Block doesn't care / variable not live. - PrefReg, ///< Block entry/exit prefers a register. - PrefSpill, ///< Block entry/exit prefers a stack slot. - PrefBoth, ///< Block entry prefers both register and stack. - MustSpill ///< A register is impossible, variable must be spilled. - }; - - /// BlockConstraint - Entry and exit constraints for a basic block. - struct BlockConstraint { - unsigned Number; ///< Basic block number (from MBB::getNumber()). - BorderConstraint Entry : 8; ///< Constraint on block entry. - BorderConstraint Exit : 8; ///< Constraint on block exit. - - /// True when this block changes the value of the live range. This means - /// the block has a non-PHI def. When this is false, a live-in value on - /// the stack can be live-out on the stack without inserting a spill. - bool ChangesValue; - }; - - /// prepare - Reset state and prepare for a new spill placement computation. - /// @param RegBundles Bit vector to receive the edge bundles where the - /// variable should be kept in a register. Each bit - /// corresponds to an edge bundle, a set bit means the - /// variable should be kept in a register through the - /// bundle. A clear bit means the variable should be - /// spilled. This vector is retained. - void prepare(BitVector &RegBundles); - - /// addConstraints - Add constraints and biases. This method may be called - /// more than once to accumulate constraints. - /// @param LiveBlocks Constraints for blocks that have the variable live in or - /// live out. - void addConstraints(ArrayRef<BlockConstraint> LiveBlocks); - - /// addPrefSpill - Add PrefSpill constraints to all blocks listed. This is - /// equivalent to calling addConstraint with identical BlockConstraints with - /// Entry = Exit = PrefSpill, and ChangesValue = false. - /// - /// @param Blocks Array of block numbers that prefer to spill in and out. - /// @param Strong When true, double the negative bias for these blocks. - void addPrefSpill(ArrayRef<unsigned> Blocks, bool Strong); - - /// addLinks - Add transparent blocks with the given numbers. - void addLinks(ArrayRef<unsigned> Links); - - /// scanActiveBundles - Perform an initial scan of all bundles activated by - /// addConstraints and addLinks, updating their state. Add all the bundles - /// that now prefer a register to RecentPositive. - /// Prepare internal data structures for iterate. - /// Return true is there are any positive nodes. - bool scanActiveBundles(); - - /// iterate - Update the network iteratively until convergence, or new bundles - /// are found. - void iterate(); - - /// getRecentPositive - Return an array of bundles that became positive during - /// the previous call to scanActiveBundles or iterate. - ArrayRef<unsigned> getRecentPositive() { return RecentPositive; } - - /// finish - Compute the optimal spill code placement given the - /// constraints. No MustSpill constraints will be violated, and the smallest - /// possible number of PrefX constraints will be violated, weighted by - /// expected execution frequencies. - /// The selected bundles are returned in the bitvector passed to prepare(). - /// @return True if a perfect solution was found, allowing the variable to be - /// in a register through all relevant bundles. - bool finish(); - - /// getBlockFrequency - Return the estimated block execution frequency per - /// function invocation. - BlockFrequency getBlockFrequency(unsigned Number) const { - return BlockFrequencies[Number]; - } - -private: - bool runOnMachineFunction(MachineFunction &mf) override; - void getAnalysisUsage(AnalysisUsage &AU) const override; - void releaseMemory() override; - - void activate(unsigned n); - void setThreshold(const BlockFrequency &Entry); - - bool update(unsigned n); -}; - -} // end namespace llvm - -#endif // LLVM_LIB_CODEGEN_SPILLPLACEMENT_H |
