Imported Upstream version 5.18.0.246

Former-commit-id: 0c7ce5b1a7851e13f22acfd379b7f9fb304e4833

external/llvm/lib/Analysis/IntervalPartition.cpp

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+//===- IntervalPartition.cpp - Interval Partition module code -------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains the definition of the IntervalPartition class, which
+// calculates and represent the interval partition of a function.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Analysis/IntervalPartition.h"
+#include "llvm/Analysis/Interval.h"
+#include "llvm/Analysis/IntervalIterator.h"
+#include "llvm/Pass.h"
+#include <cassert>
+#include <utility>
+
+using namespace llvm;
+
+char IntervalPartition::ID = 0;
+
+INITIALIZE_PASS(IntervalPartition, "intervals",
+                "Interval Partition Construction", true, true)
+
+//===----------------------------------------------------------------------===//
+// IntervalPartition Implementation
+//===----------------------------------------------------------------------===//
+
+// releaseMemory - Reset state back to before function was analyzed
+void IntervalPartition::releaseMemory() {
+  for (unsigned i = 0, e = Intervals.size(); i != e; ++i)
+    delete Intervals[i];
+  IntervalMap.clear();
+  Intervals.clear();
+  RootInterval = nullptr;
+}
+
+void IntervalPartition::print(raw_ostream &O, const Module*) const {
+  for(unsigned i = 0, e = Intervals.size(); i != e; ++i)
+    Intervals[i]->print(O);
+}
+
+// addIntervalToPartition - Add an interval to the internal list of intervals,
+// and then add mappings from all of the basic blocks in the interval to the
+// interval itself (in the IntervalMap).
+void IntervalPartition::addIntervalToPartition(Interval *I) {
+  Intervals.push_back(I);
+
+  // Add mappings for all of the basic blocks in I to the IntervalPartition
+  for (Interval::node_iterator It = I->Nodes.begin(), End = I->Nodes.end();
+       It != End; ++It)
+    IntervalMap.insert(std::make_pair(*It, I));
+}
+
+// updatePredecessors - Interval generation only sets the successor fields of
+// the interval data structures.  After interval generation is complete,
+// run through all of the intervals and propagate successor info as
+// predecessor info.
+void IntervalPartition::updatePredecessors(Interval *Int) {
+  BasicBlock *Header = Int->getHeaderNode();
+  for (BasicBlock *Successor : Int->Successors)
+    getBlockInterval(Successor)->Predecessors.push_back(Header);
+}
+
+// IntervalPartition ctor - Build the first level interval partition for the
+// specified function...
+bool IntervalPartition::runOnFunction(Function &F) {
+  // Pass false to intervals_begin because we take ownership of it's memory
+  function_interval_iterator I = intervals_begin(&F, false);
+  assert(I != intervals_end(&F) && "No intervals in function!?!?!");
+
+  addIntervalToPartition(RootInterval = *I);
+
+  ++I;  // After the first one...
+
+  // Add the rest of the intervals to the partition.
+  for (function_interval_iterator E = intervals_end(&F); I != E; ++I)
+    addIntervalToPartition(*I);
+
+  // Now that we know all of the successor information, propagate this to the
+  // predecessors for each block.
+  for (unsigned i = 0, e = Intervals.size(); i != e; ++i)
+    updatePredecessors(Intervals[i]);
+  return false;
+}
+
+// IntervalPartition ctor - Build a reduced interval partition from an
+// existing interval graph.  This takes an additional boolean parameter to
+// distinguish it from a copy constructor.  Always pass in false for now.
+IntervalPartition::IntervalPartition(IntervalPartition &IP, bool)
+  : FunctionPass(ID) {
+  assert(IP.getRootInterval() && "Cannot operate on empty IntervalPartitions!");
+
+  // Pass false to intervals_begin because we take ownership of it's memory
+  interval_part_interval_iterator I = intervals_begin(IP, false);
+  assert(I != intervals_end(IP) && "No intervals in interval partition!?!?!");
+
+  addIntervalToPartition(RootInterval = *I);
+
+  ++I;  // After the first one...
+
+  // Add the rest of the intervals to the partition.
+  for (interval_part_interval_iterator E = intervals_end(IP); I != E; ++I)
+    addIntervalToPartition(*I);
+
+  // Now that we know all of the successor information, propagate this to the
+  // predecessors for each block.
+  for (unsigned i = 0, e = Intervals.size(); i != e; ++i)
+    updatePredecessors(Intervals[i]);
+}