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

1 files changed, 129 insertions, 49 deletions

diff --git a/lib/VMCore/Module.cpp b/lib/VMCore/Module.cpp
index 341e527acb..1ca70161d6 100644
--- a/lib/VMCore/Module.cpp
+++ b/lib/VMCore/Module.cpp
@@ -17,12 +17,12 @@
 #include "llvm/DerivedTypes.h"
 #include "llvm/GVMaterializer.h"
 #include "llvm/LLVMContext.h"
+#include "llvm/ADT/DenseSet.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/Support/LeakDetector.h"
 #include "SymbolTableListTraitsImpl.h"
-#include "llvm/TypeSymbolTable.h"
 #include <algorithm>
 #include <cstdarg>
 #include <cstdlib>
@@ -60,7 +60,6 @@ template class llvm::SymbolTableListTraits<GlobalAlias, Module>;
 Module::Module(StringRef MID, LLVMContext& C)
   : Context(C), Materializer(NULL), ModuleID(MID) {
   ValSymTab = new ValueSymbolTable();
-  TypeSymTab = new TypeSymbolTable();
   NamedMDSymTab = new StringMap<NamedMDNode *>();
   Context.addModule(this);
 }
@@ -74,11 +73,10 @@ Module::~Module() {
   LibraryList.clear();
   NamedMDList.clear();
   delete ValSymTab;
-  delete TypeSymTab;
   delete static_cast<StringMap<NamedMDNode *> *>(NamedMDSymTab);
 }
 
-/// Target endian information...
+/// Target endian information.
 Module::Endianness Module::getEndianness() const {
   StringRef temp = DataLayout;
   Module::Endianness ret = AnyEndianness;
@@ -340,51 +338,6 @@ void Module::eraseNamedMetadata(NamedMDNode *NMD) {
   NamedMDList.erase(NMD);
 }
 
-//===----------------------------------------------------------------------===//
-// Methods for easy access to the types in the module.
-//
-
-
-// addTypeName - Insert an entry in the symbol table mapping Str to Type.  If
-// there is already an entry for this name, true is returned and the symbol
-// table is not modified.
-//
-bool Module::addTypeName(StringRef Name, const Type *Ty) {
-  TypeSymbolTable &ST = getTypeSymbolTable();
-
-  if (ST.lookup(Name)) return true;  // Already in symtab...
-
-  // Not in symbol table?  Set the name with the Symtab as an argument so the
-  // type knows what to update...
-  ST.insert(Name, Ty);
-
-  return false;
-}
-
-/// getTypeByName - Return the type with the specified name in this module, or
-/// null if there is none by that name.
-const Type *Module::getTypeByName(StringRef Name) const {
-  const TypeSymbolTable &ST = getTypeSymbolTable();
-  return cast_or_null<Type>(ST.lookup(Name));
-}
-
-// getTypeName - If there is at least one entry in the symbol table for the
-// specified type, return it.
-//
-std::string Module::getTypeName(const Type *Ty) const {
-  const TypeSymbolTable &ST = getTypeSymbolTable();
-
-  TypeSymbolTable::const_iterator TI = ST.begin();
-  TypeSymbolTable::const_iterator TE = ST.end();
-  if ( TI == TE ) return ""; // No names for types
-
-  while (TI != TE && TI->second != Ty)
-    ++TI;
-
-  if (TI != TE)  // Must have found an entry!
-    return TI->first;
-  return "";     // Must not have found anything...
-}
 
 //===----------------------------------------------------------------------===//
 // Methods to control the materialization of GlobalValues in the Module.
@@ -471,3 +424,130 @@ void Module::removeLibrary(StringRef Lib) {
       return;
     }
 }
+
+//===----------------------------------------------------------------------===//
+// Type finding functionality.
+//===----------------------------------------------------------------------===//
+
+namespace {
+  /// TypeFinder - Walk over a module, identifying all of the types that are
+  /// used by the module.
+  class TypeFinder {
+    // To avoid walking constant expressions multiple times and other IR
+    // objects, we keep several helper maps.
+    DenseSet<const Value*> VisitedConstants;
+    DenseSet<const Type*> VisitedTypes;
+    
+    std::vector<StructType*> &StructTypes;
+  public:
+    TypeFinder(std::vector<StructType*> &structTypes)
+      : StructTypes(structTypes) {}
+    
+    void run(const Module &M) {
+      // Get types from global variables.
+      for (Module::const_global_iterator I = M.global_begin(),
+           E = M.global_end(); I != E; ++I) {
+        incorporateType(I->getType());
+        if (I->hasInitializer())
+          incorporateValue(I->getInitializer());
+      }
+      
+      // Get types from aliases.
+      for (Module::const_alias_iterator I = M.alias_begin(),
+           E = M.alias_end(); I != E; ++I) {
+        incorporateType(I->getType());
+        if (const Value *Aliasee = I->getAliasee())
+          incorporateValue(Aliasee);
+      }
+      
+      SmallVector<std::pair<unsigned, MDNode*>, 4> MDForInst;
+
+      // Get types from functions.
+      for (Module::const_iterator FI = M.begin(), E = M.end(); FI != E; ++FI) {
+        incorporateType(FI->getType());
+        
+        for (Function::const_iterator BB = FI->begin(), E = FI->end();
+             BB != E;++BB)
+          for (BasicBlock::const_iterator II = BB->begin(),
+               E = BB->end(); II != E; ++II) {
+            const Instruction &I = *II;
+            // Incorporate the type of the instruction and all its operands.
+            incorporateType(I.getType());
+            for (User::const_op_iterator OI = I.op_begin(), OE = I.op_end();
+                 OI != OE; ++OI)
+              incorporateValue(*OI);
+            
+            // Incorporate types hiding in metadata.
+            I.getAllMetadata(MDForInst);
+            for (unsigned i = 0, e = MDForInst.size(); i != e; ++i)
+              incorporateMDNode(MDForInst[i].second);
+            MDForInst.clear();
+          }
+      }
+      
+      for (Module::const_named_metadata_iterator I = M.named_metadata_begin(),
+           E = M.named_metadata_end(); I != E; ++I) {
+        const NamedMDNode *NMD = I;
+        for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i)
+          incorporateMDNode(NMD->getOperand(i));
+      }
+    }
+    
+  private:
+    void incorporateType(Type *Ty) {
+      // Check to see if we're already visited this type.
+      if (!VisitedTypes.insert(Ty).second)
+        return;
+      
+      // If this is a structure or opaque type, add a name for the type.
+      if (StructType *STy = dyn_cast<StructType>(Ty))
+        StructTypes.push_back(STy);
+      
+      // Recursively walk all contained types.
+      for (Type::subtype_iterator I = Ty->subtype_begin(),
+           E = Ty->subtype_end(); I != E; ++I)
+        incorporateType(*I);
+    }
+    
+    /// incorporateValue - This method is used to walk operand lists finding
+    /// types hiding in constant expressions and other operands that won't be
+    /// walked in other ways.  GlobalValues, basic blocks, instructions, and
+    /// inst operands are all explicitly enumerated.
+    void incorporateValue(const Value *V) {
+      if (const MDNode *M = dyn_cast<MDNode>(V))
+        return incorporateMDNode(M);
+      if (!isa<Constant>(V) || isa<GlobalValue>(V)) return;
+      
+      // Already visited?
+      if (!VisitedConstants.insert(V).second)
+        return;
+      
+      // Check this type.
+      incorporateType(V->getType());
+      
+      // Look in operands for types.
+      const User *U = cast<User>(V);
+      for (Constant::const_op_iterator I = U->op_begin(),
+           E = U->op_end(); I != E;++I)
+        incorporateValue(*I);
+    }
+    
+    void incorporateMDNode(const MDNode *V) {
+      
+      // Already visited?
+      if (!VisitedConstants.insert(V).second)
+        return;
+      
+      // Look in operands for types.
+      for (unsigned i = 0, e = V->getNumOperands(); i != e; ++i)
+        if (Value *Op = V->getOperand(i))
+          incorporateValue(Op);
+    }
+  };
+} // end anonymous namespace
+
+void Module::findUsedStructTypes(std::vector<StructType*> &StructTypes) const {
+  TypeFinder(StructTypes).run(*this);
+}
+
+