From 1afcace3a3a138b1b18e5c6270caa8dae2261ae2 Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Sat, 9 Jul 2011 17:41:24 +0000
Subject: Land the long talked about "type system rewrite" patch.  This patch
 brings numerous advantages to LLVM.  One way to look at it is through
 diffstat:  109 files changed, 3005 insertions(+), 5906 deletions(-)

Removing almost 3K lines of code is a good thing.  Other advantages
include:

1. Value::getType() is a simple load that can be CSE'd, not a mutating
   union-find operation.
2. Types a uniqued and never move once created, defining away PATypeHolder.
3. Structs can be "named" now, and their name is part of the identity that
   uniques them.  This means that the compiler doesn't merge them structurally
   which makes the IR much less confusing.
4. Now that there is no way to get a cycle in a type graph without a named
   struct type, "upreferences" go away.
5. Type refinement is completely gone, which should make LTO much MUCH faster
   in some common cases with C++ code.
6. Types are now generally immutable, so we can use "Type *" instead
   "const Type *" everywhere.

Downsides of this patch are that it removes some functions from the C API,
so people using those will have to upgrade to (not yet added) new API.
"LLVM 3.0" is the right time to do this.

There are still some cleanups pending after this, this patch is large enough
as-is.




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134829 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/Transforms/IPO.h               |  7 ------
 include/llvm/Transforms/Utils/ValueMapper.h | 34 +++++++++++++++++++++++++++--
 2 files changed, 32 insertions(+), 9 deletions(-)

(limited to 'include/llvm/Transforms')

diff --git a/include/llvm/Transforms/IPO.h b/include/llvm/Transforms/IPO.h
index d12fd1d..f025e18 100644
--- a/include/llvm/Transforms/IPO.h
+++ b/include/llvm/Transforms/IPO.h
@@ -74,13 +74,6 @@ ModulePass *createGlobalOptimizerPass();
 
 
 //===----------------------------------------------------------------------===//
-/// createDeadTypeEliminationPass - Return a new pass that eliminates symbol
-/// table entries for types that are never used.
-///
-ModulePass *createDeadTypeEliminationPass();
-
-
-//===----------------------------------------------------------------------===//
 /// createGlobalDCEPass - This transform is designed to eliminate unreachable
 /// internal globals (functions or global variables)
 ///
diff --git a/include/llvm/Transforms/Utils/ValueMapper.h b/include/llvm/Transforms/Utils/ValueMapper.h
index d612213..c786342 100644
--- a/include/llvm/Transforms/Utils/ValueMapper.h
+++ b/include/llvm/Transforms/Utils/ValueMapper.h
@@ -22,6 +22,18 @@ namespace llvm {
   class Instruction;
   typedef ValueMap<const Value *, TrackingVH<Value> > ValueToValueMapTy;
 
+  /// ValueMapTypeRemapper - This is a class that can be implemented by clients
+  /// to remap types when cloning constants and instructions.
+  class ValueMapTypeRemapper {
+    virtual void Anchor();  // Out of line method.
+  public:
+    ~ValueMapTypeRemapper() {}
+    
+    /// remapType - The client should implement this method if they want to
+    /// remap types while mapping values.
+    virtual Type *remapType(Type *SrcTy) = 0;
+  };
+  
   /// RemapFlags - These are flags that the value mapping APIs allow.
   enum RemapFlags {
     RF_None = 0,
@@ -42,9 +54,27 @@ namespace llvm {
   }
   
   Value *MapValue(const Value *V, ValueToValueMapTy &VM,
-                  RemapFlags Flags = RF_None);
+                  RemapFlags Flags = RF_None,
+                  ValueMapTypeRemapper *TypeMapper = 0);
+
   void RemapInstruction(Instruction *I, ValueToValueMapTy &VM,
-                        RemapFlags Flags = RF_None);
+                        RemapFlags Flags = RF_None,
+                        ValueMapTypeRemapper *TypeMapper = 0);
+  
+  /// MapValue - provide versions that preserve type safety for MDNode and
+  /// Constants.
+  inline MDNode *MapValue(const MDNode *V, ValueToValueMapTy &VM,
+                          RemapFlags Flags = RF_None,
+                          ValueMapTypeRemapper *TypeMapper = 0) {
+    return (MDNode*)MapValue((const Value*)V, VM, Flags, TypeMapper);
+  }
+  inline Constant *MapValue(const Constant *V, ValueToValueMapTy &VM,
+                            RemapFlags Flags = RF_None,
+                            ValueMapTypeRemapper *TypeMapper = 0) {
+    return (Constant*)MapValue((const Value*)V, VM, Flags, TypeMapper);
+  }
+  
+
 } // End llvm namespace
 
 #endif
-- 
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