vendor/llvm/llvm-r130700

1 files changed, 163 insertions, 0 deletions

diff --git a/lib/CodeGen/InterferenceCache.h b/lib/CodeGen/InterferenceCache.h
new file mode 100644
index 000000000000..6c36fa4021fb
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+++ b/lib/CodeGen/InterferenceCache.h
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+//===-- InterferenceCache.h - Caching per-block interference ---*- C++ -*--===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// InterferenceCache remembers per-block interference in LiveIntervalUnions.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CODEGEN_INTERFERENCECACHE
+#define LLVM_CODEGEN_INTERFERENCECACHE
+
+#include "LiveIntervalUnion.h"
+
+namespace llvm {
+
+class InterferenceCache {
+  const TargetRegisterInfo *TRI;
+  LiveIntervalUnion *LIUArray;
+  SlotIndexes *Indexes;
+  MachineFunction *MF;
+
+  /// BlockInterference - information about the interference in a single basic
+  /// block.
+  struct BlockInterference {
+    BlockInterference() : Tag(0) {}
+    unsigned Tag;
+    SlotIndex First;
+    SlotIndex Last;
+  };
+
+  /// Entry - A cache entry containing interference information for all aliases
+  /// of PhysReg in all basic blocks.
+  class Entry {
+    /// PhysReg - The register currently represented.
+    unsigned PhysReg;
+
+    /// Tag - Cache tag is changed when any of the underlying LiveIntervalUnions
+    /// change.
+    unsigned Tag;
+
+    /// MF - The current function.
+    MachineFunction *MF;
+
+    /// Indexes - Mapping block numbers to SlotIndex ranges.
+    SlotIndexes *Indexes;
+
+    /// PrevPos - The previous position the iterators were moved to.
+    SlotIndex PrevPos;
+
+    /// AliasTags - A LiveIntervalUnion pointer and tag for each alias of
+    /// PhysReg.
+    SmallVector<std::pair<LiveIntervalUnion*, unsigned>, 8> Aliases;
+
+    typedef LiveIntervalUnion::SegmentIter Iter;
+
+    /// Iters - an iterator for each alias
+    SmallVector<Iter, 8> Iters;
+
+    /// Blocks - Interference for each block in the function.
+    SmallVector<BlockInterference, 8> Blocks;
+
+    /// update - Recompute Blocks[MBBNum]
+    void update(unsigned MBBNum);
+
+  public:
+    Entry() : PhysReg(0), Tag(0), Indexes(0) {}
+
+    void clear(MachineFunction *mf, SlotIndexes *indexes) {
+      PhysReg = 0;
+      MF = mf;
+      Indexes = indexes;
+    }
+
+    unsigned getPhysReg() const { return PhysReg; }
+
+    void revalidate();
+
+    /// valid - Return true if this is a valid entry for physReg.
+    bool valid(LiveIntervalUnion *LIUArray, const TargetRegisterInfo *TRI);
+
+    /// reset - Initialize entry to represent physReg's aliases.
+    void reset(unsigned physReg,
+               LiveIntervalUnion *LIUArray,
+               const TargetRegisterInfo *TRI,
+               const MachineFunction *MF);
+
+    /// get - Return an up to date BlockInterference.
+    BlockInterference *get(unsigned MBBNum) {
+      if (Blocks[MBBNum].Tag != Tag)
+        update(MBBNum);
+      return &Blocks[MBBNum];
+    }
+  };
+
+  // We don't keep a cache entry for every physical register, that would use too
+  // much memory. Instead, a fixed number of cache entries are used in a round-
+  // robin manner.
+  enum { CacheEntries = 32 };
+
+  // Point to an entry for each physreg. The entry pointed to may not be up to
+  // date, and it may have been reused for a different physreg.
+  SmallVector<unsigned char, 2> PhysRegEntries;
+
+  // Next round-robin entry to be picked.
+  unsigned RoundRobin;
+
+  // The actual cache entries.
+  Entry Entries[CacheEntries];
+
+  // get - Get a valid entry for PhysReg.
+  Entry *get(unsigned PhysReg);
+
+public:
+  InterferenceCache() : TRI(0), LIUArray(0), Indexes(0), MF(0), RoundRobin(0) {}
+
+  /// init - Prepare cache for a new function.
+  void init(MachineFunction*, LiveIntervalUnion*, SlotIndexes*,
+            const TargetRegisterInfo *);
+
+  /// Cursor - The primary query interface for the block interference cache.
+  class Cursor {
+    Entry *CacheEntry;
+    BlockInterference *Current;
+  public:
+    /// Cursor - Create a cursor for the interference allocated to PhysReg and
+    /// all its aliases.
+    Cursor(InterferenceCache &Cache, unsigned PhysReg)
+      : CacheEntry(Cache.get(PhysReg)), Current(0) {}
+
+    /// moveTo - Move cursor to basic block MBBNum.
+    void moveToBlock(unsigned MBBNum) {
+      Current = CacheEntry->get(MBBNum);
+    }
+
+    /// hasInterference - Return true if the current block has any interference.
+    bool hasInterference() {
+      return Current->First.isValid();
+    }
+
+    /// first - Return the starting index of the first interfering range in the
+    /// current block.
+    SlotIndex first() {
+      return Current->First;
+    }
+
+    /// last - Return the ending index of the last interfering range in the
+    /// current block.
+    SlotIndex last() {
+      return Current->Last;
+    }
+  };
+
+  friend class Cursor;
+};
+
+} // namespace llvm
+
+#endif