From c2c50cdcdc19a1bca993c06d13d8cdca87083ce4 Mon Sep 17 00:00:00 2001
From: Chandler Carruth <chandlerc@gmail.com>
Date: Wed, 2 Jan 2013 09:10:48 +0000
Subject: Rename VMCore directory to IR.

Aside from moving the actual files, this patch only updates the build
system and the source file comments under lib/... that are relevant.

I'll be updating other docs and other files in smaller subsequnet
commits.

While I've tried to test this, but it is entirely possible that there
will still be some build system fallout.

Also, note that I've not changed the library name itself: libLLVMCore.a
is still the library name. I'd be interested in others' opinions about
whether we should rename this as well (I think we should, just not sure
what it might break)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171359 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/IR/Use.cpp | 145 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 145 insertions(+)
 create mode 100644 lib/IR/Use.cpp

(limited to 'lib/IR/Use.cpp')

diff --git a/lib/IR/Use.cpp b/lib/IR/Use.cpp
new file mode 100644
index 0000000000..0128adc3f7
--- /dev/null
+++ b/lib/IR/Use.cpp
@@ -0,0 +1,145 @@
+//===-- Use.cpp - Implement the Use class ---------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the algorithm for finding the User of a Use.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Value.h"
+#include <new>
+
+namespace llvm {
+
+//===----------------------------------------------------------------------===//
+//                         Use swap Implementation
+//===----------------------------------------------------------------------===//
+
+void Use::swap(Use &RHS) {
+  Value *V1(Val);
+  Value *V2(RHS.Val);
+  if (V1 != V2) {
+    if (V1) {
+      removeFromList();
+    }
+
+    if (V2) {
+      RHS.removeFromList();
+      Val = V2;
+      V2->addUse(*this);
+    } else {
+      Val = 0;
+    }
+
+    if (V1) {
+      RHS.Val = V1;
+      V1->addUse(RHS);
+    } else {
+      RHS.Val = 0;
+    }
+  }
+}
+
+//===----------------------------------------------------------------------===//
+//                         Use getImpliedUser Implementation
+//===----------------------------------------------------------------------===//
+
+const Use *Use::getImpliedUser() const {
+  const Use *Current = this;
+
+  while (true) {
+    unsigned Tag = (Current++)->Prev.getInt();
+    switch (Tag) {
+      case zeroDigitTag:
+      case oneDigitTag:
+        continue;
+
+      case stopTag: {
+        ++Current;
+        ptrdiff_t Offset = 1;
+        while (true) {
+          unsigned Tag = Current->Prev.getInt();
+          switch (Tag) {
+            case zeroDigitTag:
+            case oneDigitTag:
+              ++Current;
+              Offset = (Offset << 1) + Tag;
+              continue;
+            default:
+              return Current + Offset;
+          }
+        }
+      }
+
+      case fullStopTag:
+        return Current;
+    }
+  }
+}
+
+//===----------------------------------------------------------------------===//
+//                         Use initTags Implementation
+//===----------------------------------------------------------------------===//
+
+Use *Use::initTags(Use * const Start, Use *Stop) {
+  ptrdiff_t Done = 0;
+  while (Done < 20) {
+    if (Start == Stop--)
+      return Start;
+    static const PrevPtrTag tags[20] = { fullStopTag, oneDigitTag, stopTag,
+                                         oneDigitTag, oneDigitTag, stopTag,
+                                         zeroDigitTag, oneDigitTag, oneDigitTag,
+                                         stopTag, zeroDigitTag, oneDigitTag,
+                                         zeroDigitTag, oneDigitTag, stopTag,
+                                         oneDigitTag, oneDigitTag, oneDigitTag,
+                                         oneDigitTag, stopTag
+                                       };
+    new(Stop) Use(tags[Done++]);
+  }
+
+  ptrdiff_t Count = Done;
+  while (Start != Stop) {
+    --Stop;
+    if (!Count) {
+      new(Stop) Use(stopTag);
+      ++Done;
+      Count = Done;
+    } else {
+      new(Stop) Use(PrevPtrTag(Count & 1));
+      Count >>= 1;
+      ++Done;
+    }
+  }
+
+  return Start;
+}
+
+//===----------------------------------------------------------------------===//
+//                         Use zap Implementation
+//===----------------------------------------------------------------------===//
+
+void Use::zap(Use *Start, const Use *Stop, bool del) {
+  while (Start != Stop)
+    (--Stop)->~Use();
+  if (del)
+    ::operator delete(Start);
+}
+
+//===----------------------------------------------------------------------===//
+//                         Use getUser Implementation
+//===----------------------------------------------------------------------===//
+
+User *Use::getUser() const {
+  const Use *End = getImpliedUser();
+  const UserRef *ref = reinterpret_cast<const UserRef*>(End);
+  return ref->getInt()
+    ? ref->getPointer()
+    : (User*)End;
+}
+
+} // End llvm namespace
-- 
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