Subversion Repositories QNX 8.QNX8 LLVM/Clang compiler suite

Rev

Blame | Last modification | View Log | Download | RSS feed

  1. //===- GISelWorkList.h - Worklist for GISel passes ----*- C++ -*-===//
  2. //
  3. // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
  4. // See https://llvm.org/LICENSE.txt for license information.
  5. // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
  6. //
  7. //===----------------------------------------------------------------------===//
  8.  
  9. #ifndef LLVM_CODEGEN_GLOBALISEL_GISELWORKLIST_H
  10. #define LLVM_CODEGEN_GLOBALISEL_GISELWORKLIST_H
  11.  
  12. #include "llvm/ADT/DenseMap.h"
  13. #include "llvm/ADT/SmallVector.h"
  14.  
  15. namespace llvm {
  16.  
  17. class MachineInstr;
  18.  
  19. // Worklist which mostly works similar to InstCombineWorkList, but on
  20. // MachineInstrs. The main difference with something like a SetVector is that
  21. // erasing an element doesn't move all elements over one place - instead just
  22. // nulls out the element of the vector.
  23. //
  24. // FIXME: Does it make sense to factor out common code with the
  25. // instcombinerWorkList?
  26. template<unsigned N>
  27. class GISelWorkList {
  28.   SmallVector<MachineInstr *, N> Worklist;
  29.   DenseMap<MachineInstr *, unsigned> WorklistMap;
  30.  
  31. #if LLVM_ENABLE_ABI_BREAKING_CHECKS
  32.   bool Finalized = true;
  33. #endif
  34.  
  35. public:
  36.   GISelWorkList() : WorklistMap(N) {}
  37.  
  38.   bool empty() const { return WorklistMap.empty(); }
  39.  
  40.   unsigned size() const { return WorklistMap.size(); }
  41.  
  42.   // Since we don't know ahead of time how many instructions we're going to add
  43.   // to the worklist, and migrating densemap's elements is quite expensive
  44.   // everytime we resize, only insert to the smallvector (typically during the
  45.   // initial phase of populating lists). Before the worklist can be used,
  46.   // finalize should be called. Also assert with NDEBUG if list is ever used
  47.   // without finalizing. Note that unlike insert, we won't check for duplicates
  48.   // - so the ideal place to use this is during the initial prepopulating phase
  49.   // of most passes.
  50.   void deferred_insert(MachineInstr *I) {
  51.     Worklist.push_back(I);
  52. #if LLVM_ENABLE_ABI_BREAKING_CHECKS
  53.     Finalized = false;
  54. #endif
  55.   }
  56.  
  57.   // This should only be called when using deferred_insert.
  58.   // This asserts that the WorklistMap is empty, and then
  59.   // inserts all the elements in the Worklist into the map.
  60.   // It also asserts if there are any duplicate elements found.
  61.   void finalize() {
  62.     assert(WorklistMap.empty() && "Expecting empty worklistmap");
  63.     if (Worklist.size() > N)
  64.       WorklistMap.reserve(Worklist.size());
  65.     for (unsigned i = 0; i < Worklist.size(); ++i)
  66.       if (!WorklistMap.try_emplace(Worklist[i], i).second)
  67.         llvm_unreachable("Duplicate elements in the list");
  68. #if LLVM_ENABLE_ABI_BREAKING_CHECKS
  69.     Finalized = true;
  70. #endif
  71.   }
  72.  
  73.   /// Add the specified instruction to the worklist if it isn't already in it.
  74.   void insert(MachineInstr *I) {
  75. #if LLVM_ENABLE_ABI_BREAKING_CHECKS
  76.     assert(Finalized && "GISelWorkList used without finalizing");
  77. #endif
  78.     if (WorklistMap.try_emplace(I, Worklist.size()).second)
  79.       Worklist.push_back(I);
  80.   }
  81.  
  82.   /// Remove I from the worklist if it exists.
  83.   void remove(const MachineInstr *I) {
  84. #if LLVM_ENABLE_ABI_BREAKING_CHECKS
  85.     assert((Finalized || WorklistMap.empty()) && "Neither finalized nor empty");
  86. #endif
  87.     auto It = WorklistMap.find(I);
  88.     if (It == WorklistMap.end())
  89.       return; // Not in worklist.
  90.  
  91.     // Don't bother moving everything down, just null out the slot.
  92.     Worklist[It->second] = nullptr;
  93.  
  94.     WorklistMap.erase(It);
  95.   }
  96.  
  97.   void clear() {
  98.     Worklist.clear();
  99.     WorklistMap.clear();
  100.   }
  101.  
  102.   MachineInstr *pop_back_val() {
  103. #if LLVM_ENABLE_ABI_BREAKING_CHECKS
  104.     assert(Finalized && "GISelWorkList used without finalizing");
  105. #endif
  106.     MachineInstr *I;
  107.     do {
  108.       I = Worklist.pop_back_val();
  109.     } while(!I);
  110.     assert(I && "Pop back on empty worklist");
  111.     WorklistMap.erase(I);
  112.     return I;
  113.   }
  114. };
  115.  
  116. } // end namespace llvm.
  117.  
  118. #endif
  119.