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

5 files changed, 15 insertions, 128 deletions

diff --git a/lib/Transforms/IPO/CMakeLists.txt b/lib/Transforms/IPO/CMakeLists.txt
index 179b150c14..3de7bfceed 100644
--- a/lib/Transforms/IPO/CMakeLists.txt
+++ b/lib/Transforms/IPO/CMakeLists.txt
@@ -2,7 +2,6 @@ add_llvm_library(LLVMipo
   ArgumentPromotion.cpp
   ConstantMerge.cpp
   DeadArgumentElimination.cpp
-  DeadTypeElimination.cpp
   ExtractGV.cpp
   FunctionAttrs.cpp
   GlobalDCE.cpp
diff --git a/lib/Transforms/IPO/DeadTypeElimination.cpp b/lib/Transforms/IPO/DeadTypeElimination.cpp
deleted file mode 100644
index d3d4963b63..0000000000
--- a/lib/Transforms/IPO/DeadTypeElimination.cpp
+++ /dev/null
@@ -1,112 +0,0 @@
-//===- DeadTypeElimination.cpp - Eliminate unused types for symbol table --===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// This pass is used to cleanup the output of GCC.  It eliminate names for types
-// that are unused in the entire translation unit, using the FindUsedTypes pass.
-//
-//===----------------------------------------------------------------------===//
-
-#define DEBUG_TYPE "deadtypeelim"
-#include "llvm/Transforms/IPO.h"
-#include "llvm/Analysis/FindUsedTypes.h"
-#include "llvm/Module.h"
-#include "llvm/TypeSymbolTable.h"
-#include "llvm/DerivedTypes.h"
-#include "llvm/ADT/Statistic.h"
-using namespace llvm;
-
-STATISTIC(NumKilled, "Number of unused typenames removed from symtab");
-
-namespace {
-  struct DTE : public ModulePass {
-    static char ID; // Pass identification, replacement for typeid
-    DTE() : ModulePass(ID) {
-      initializeDTEPass(*PassRegistry::getPassRegistry());
-    }
-
-    // doPassInitialization - For this pass, it removes global symbol table
-    // entries for primitive types.  These are never used for linking in GCC and
-    // they make the output uglier to look at, so we nuke them.
-    //
-    // Also, initialize instance variables.
-    //
-    bool runOnModule(Module &M);
-
-    // getAnalysisUsage - This function needs FindUsedTypes to do its job...
-    //
-    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
-      AU.addRequired<FindUsedTypes>();
-    }
-  };
-}
-
-char DTE::ID = 0;
-INITIALIZE_PASS_BEGIN(DTE, "deadtypeelim", "Dead Type Elimination",
-                      false, false)
-INITIALIZE_PASS_DEPENDENCY(FindUsedTypes)
-INITIALIZE_PASS_END(DTE, "deadtypeelim", "Dead Type Elimination", false, false)
-
-ModulePass *llvm::createDeadTypeEliminationPass() {
-  return new DTE();
-}
-
-
-// ShouldNukeSymtabEntry - Return true if this module level symbol table entry
-// should be eliminated.
-//
-static inline bool ShouldNukeSymtabEntry(const Type *Ty){
-  // Nuke all names for primitive types!
-  if (Ty->isPrimitiveType() || Ty->isIntegerTy()) 
-    return true;
-
-  // Nuke all pointers to primitive types as well...
-  if (const PointerType *PT = dyn_cast<PointerType>(Ty))
-    if (PT->getElementType()->isPrimitiveType() ||
-        PT->getElementType()->isIntegerTy()) 
-      return true;
-
-  return false;
-}
-
-// run - For this pass, it removes global symbol table entries for primitive
-// types.  These are never used for linking in GCC and they make the output
-// uglier to look at, so we nuke them.  Also eliminate types that are never used
-// in the entire program as indicated by FindUsedTypes.
-//
-bool DTE::runOnModule(Module &M) {
-  bool Changed = false;
-
-  TypeSymbolTable &ST = M.getTypeSymbolTable();
-  const SetVector<const Type*> &T = getAnalysis<FindUsedTypes>().getTypes();
-  std::set<const Type*> UsedTypes(T.begin(), T.end());
-
-  // Check the symbol table for superfluous type entries...
-  //
-  // Grab the 'type' plane of the module symbol...
-  TypeSymbolTable::iterator TI = ST.begin();
-  TypeSymbolTable::iterator TE = ST.end();
-  while ( TI != TE ) {
-    // If this entry should be unconditionally removed, or if we detect that
-    // the type is not used, remove it.
-    const Type *RHS = TI->second;
-    if (ShouldNukeSymtabEntry(RHS) || !UsedTypes.count(RHS)) {
-      ST.remove(TI++);
-      ++NumKilled;
-      Changed = true;
-    } else {
-      ++TI;
-      // We only need to leave one name for each type.
-      UsedTypes.erase(RHS);
-    }
-  }
-
-  return Changed;
-}
-
-// vim: sw=2
diff --git a/lib/Transforms/IPO/IPO.cpp b/lib/Transforms/IPO/IPO.cpp
index 21dcb519d9..31ce95f53d 100644
--- a/lib/Transforms/IPO/IPO.cpp
+++ b/lib/Transforms/IPO/IPO.cpp
@@ -25,7 +25,6 @@ void llvm::initializeIPO(PassRegistry &Registry) {
   initializeConstantMergePass(Registry);
   initializeDAEPass(Registry);
   initializeDAHPass(Registry);
-  initializeDTEPass(Registry);
   initializeFunctionAttrsPass(Registry);
   initializeGlobalDCEPass(Registry);
   initializeGlobalOptPass(Registry);
@@ -63,10 +62,6 @@ void LLVMAddDeadArgEliminationPass(LLVMPassManagerRef PM) {
   unwrap(PM)->add(createDeadArgEliminationPass());
 }
 
-void LLVMAddDeadTypeEliminationPass(LLVMPassManagerRef PM) {
-  unwrap(PM)->add(createDeadTypeEliminationPass());
-}
-
 void LLVMAddFunctionAttrsPass(LLVMPassManagerRef PM) {
   unwrap(PM)->add(createFunctionAttrsPass());
 }
diff --git a/lib/Transforms/IPO/MergeFunctions.cpp b/lib/Transforms/IPO/MergeFunctions.cpp
index f74144338a..183ba63e9f 100644
--- a/lib/Transforms/IPO/MergeFunctions.cpp
+++ b/lib/Transforms/IPO/MergeFunctions.cpp
@@ -218,7 +218,6 @@ bool FunctionComparator::isEquivalentType(const Type *Ty1,
     llvm_unreachable("Unknown type!");
     // Fall through in Release mode.
   case Type::IntegerTyID:
-  case Type::OpaqueTyID:
   case Type::VectorTyID:
     // Ty1 == Ty2 would have returned true earlier.
     return false;
diff --git a/lib/Transforms/IPO/StripSymbols.cpp b/lib/Transforms/IPO/StripSymbols.cpp
index a690765108..5bacdf57fc 100644
--- a/lib/Transforms/IPO/StripSymbols.cpp
+++ b/lib/Transforms/IPO/StripSymbols.cpp
@@ -28,8 +28,8 @@
 #include "llvm/Pass.h"
 #include "llvm/Analysis/DebugInfo.h"
 #include "llvm/ValueSymbolTable.h"
-#include "llvm/TypeSymbolTable.h"
 #include "llvm/Transforms/Utils/Local.h"
+#include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/SmallPtrSet.h"
 using namespace llvm;
 
@@ -174,13 +174,19 @@ static void StripSymtab(ValueSymbolTable &ST, bool PreserveDbgInfo) {
   }
 }
 
-// Strip the symbol table of its names.
-static void StripTypeSymtab(TypeSymbolTable &ST, bool PreserveDbgInfo) {
-  for (TypeSymbolTable::iterator TI = ST.begin(), E = ST.end(); TI != E; ) {
-    if (PreserveDbgInfo && StringRef(TI->first).startswith("llvm.dbg"))
-      ++TI;
-    else
-      ST.remove(TI++);
+// Strip any named types of their names.
+static void StripTypeNames(Module &M, bool PreserveDbgInfo) {
+  std::vector<StructType*> StructTypes;
+  M.findUsedStructTypes(StructTypes);
+
+  for (unsigned i = 0, e = StructTypes.size(); i != e; ++i) {
+    StructType *STy = StructTypes[i];
+    if (STy->isAnonymous() || STy->getName().empty()) continue;
+    
+    if (PreserveDbgInfo && STy->getName().startswith("llvm.dbg"))
+      continue;
+
+    STy->setName("");
   }
 }
 
@@ -221,7 +227,7 @@ static bool StripSymbolNames(Module &M, bool PreserveDbgInfo) {
   }
   
   // Remove all names from types.
-  StripTypeSymtab(M.getTypeSymbolTable(), PreserveDbgInfo);
+  StripTypeNames(M, PreserveDbgInfo);
 
   return true;
 }