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.

llvm-svn: 134829

1 files changed, 43 insertions, 44 deletions

diff --git a/llvm/lib/AsmParser/LLParser.h b/llvm/lib/AsmParser/LLParser.h
index c486799f292..96306578506 100644
--- a/llvm/lib/AsmParser/LLParser.h
+++ b/llvm/lib/AsmParser/LLParser.h
@@ -18,6 +18,7 @@
 #include "llvm/Module.h"
 #include "llvm/Type.h"
 #include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/StringMap.h"
 #include "llvm/Support/ValueHandle.h"
 #include <map>
 
@@ -32,6 +33,7 @@ namespace llvm {
   class GlobalValue;
   class MDString;
   class MDNode;
+  class StructType;
 
   /// ValID - Represents a reference of a definition of some sort with no type.
   /// There are several cases where we have to parse the value but where the
@@ -47,7 +49,9 @@ namespace llvm {
       t_Constant,                 // Value in ConstantVal.
       t_InlineAsm,                // Value in StrVal/StrVal2/UIntVal.
       t_MDNode,                   // Value in MDNodeVal.
-      t_MDString                  // Value in MDStringVal.
+      t_MDString,                 // Value in MDStringVal.
+      t_ConstantStruct,           // Value in ConstantStructElts.
+      t_PackedConstantStruct      // Value in ConstantStructElts.
     } Kind;
     
     LLLexer::LocTy Loc;
@@ -58,12 +62,19 @@ namespace llvm {
     Constant *ConstantVal;
     MDNode *MDNodeVal;
     MDString *MDStringVal;
-    ValID() : APFloatVal(0.0) {}
+    Constant **ConstantStructElts;
+    
+    ValID() : Kind(t_LocalID), APFloatVal(0.0) {}
+    ~ValID() {
+      if (Kind == t_ConstantStruct || Kind == t_PackedConstantStruct)
+        delete [] ConstantStructElts;
+    }
     
     bool operator<(const ValID &RHS) const {
       if (Kind == t_LocalID || Kind == t_GlobalID)
         return UIntVal < RHS.UIntVal;
-      assert((Kind == t_LocalName || Kind == t_GlobalName) && 
+      assert((Kind == t_LocalName || Kind == t_GlobalName ||
+              Kind == t_ConstantStruct || Kind == t_PackedConstantStruct) && 
              "Ordering not defined for this ValID kind yet");
       return StrVal < RHS.StrVal;
     }
@@ -93,33 +104,13 @@ namespace llvm {
     };
     DenseMap<Instruction*, std::vector<MDRef> > ForwardRefInstMetadata;
 
-    // Type resolution handling data structures.
-    std::map<std::string, std::pair<PATypeHolder, LocTy> > ForwardRefTypes;
-    std::map<unsigned, std::pair<PATypeHolder, LocTy> > ForwardRefTypeIDs;
-    std::vector<PATypeHolder> NumberedTypes;
+    // Type resolution handling data structures.  The location is set when we
+    // have processed a use of the type but not a definition yet.
+    StringMap<std::pair<Type*, LocTy> > NamedTypes;
+    std::vector<std::pair<Type*, LocTy> > NumberedTypes;
+    
     std::vector<TrackingVH<MDNode> > NumberedMetadata;
     std::map<unsigned, std::pair<TrackingVH<MDNode>, LocTy> > ForwardRefMDNodes;
-    struct UpRefRecord {
-      /// Loc - This is the location of the upref.
-      LocTy Loc;
-
-      /// NestingLevel - The number of nesting levels that need to be popped
-      /// before this type is resolved.
-      unsigned NestingLevel;
-
-      /// LastContainedTy - This is the type at the current binding level for
-      /// the type.  Every time we reduce the nesting level, this gets updated.
-      const Type *LastContainedTy;
-
-      /// UpRefTy - This is the actual opaque type that the upreference is
-      /// represented with.
-      OpaqueType *UpRefTy;
-
-      UpRefRecord(LocTy L, unsigned NL, OpaqueType *URTy)
-        : Loc(L), NestingLevel(NL), LastContainedTy((Type*)URTy),
-          UpRefTy(URTy) {}
-    };
-    std::vector<UpRefRecord> UpRefs;
 
     // Global Value reference information.
     std::map<std::string, std::pair<GlobalValue*, LocTy> > ForwardRefVals;
@@ -137,7 +128,7 @@ namespace llvm {
       M(m) {}
     bool Run();
 
-    LLVMContext& getContext() { return Context; }
+    LLVMContext &getContext() { return Context; }
 
   private:
 
@@ -222,16 +213,19 @@ namespace llvm {
     bool ParseMDNodeID(MDNode *&Result, unsigned &SlotNo);
 
     // Type Parsing.
-    bool ParseType(PATypeHolder &Result, bool AllowVoid = false);
-    bool ParseType(PATypeHolder &Result, LocTy &Loc, bool AllowVoid = false) {
+    bool ParseType(Type *&Result, bool AllowVoid = false);
+    bool ParseType(Type *&Result, LocTy &Loc, bool AllowVoid = false) {
       Loc = Lex.getLoc();
       return ParseType(Result, AllowVoid);
     }
-    bool ParseTypeRec(PATypeHolder &H);
-    bool ParseStructType(PATypeHolder &H, bool Packed);
-    bool ParseArrayVectorType(PATypeHolder &H, bool isVector);
-    bool ParseFunctionType(PATypeHolder &Result);
-    PATypeHolder HandleUpRefs(const Type *Ty);
+    bool ParseAnonStructType(Type *&Result, bool Packed);
+    bool ParseStructBody(SmallVectorImpl<Type*> &Body);
+    bool ParseStructDefinition(SMLoc TypeLoc, StringRef Name,
+                               std::pair<Type*, LocTy> &Entry,
+                               Type *&ResultTy);
+
+    bool ParseArrayVectorType(Type *&Result, bool isVector);
+    bool ParseFunctionType(Type *&Result);
 
     // Function Semantic Analysis.
     class PerFunctionState {
@@ -278,14 +272,20 @@ namespace llvm {
     bool ConvertValIDToValue(const Type *Ty, ValID &ID, Value *&V,
                              PerFunctionState *PFS);
 
-    bool ParseValue(const Type *Ty, Value *&V, PerFunctionState &PFS);
+    bool ParseValue(const Type *Ty, Value *&V, PerFunctionState *PFS);
+    bool ParseValue(const Type *Ty, Value *&V, PerFunctionState &PFS) {
+      return ParseValue(Ty, V, &PFS);
+    }
     bool ParseValue(const Type *Ty, Value *&V, LocTy &Loc,
                     PerFunctionState &PFS) {
       Loc = Lex.getLoc();
-      return ParseValue(Ty, V, PFS);
+      return ParseValue(Ty, V, &PFS);
     }
 
-    bool ParseTypeAndValue(Value *&V, PerFunctionState &PFS);
+    bool ParseTypeAndValue(Value *&V, PerFunctionState *PFS);
+    bool ParseTypeAndValue(Value *&V, PerFunctionState &PFS) {
+      return ParseTypeAndValue(V, &PFS);
+    }
     bool ParseTypeAndValue(Value *&V, LocTy &Loc, PerFunctionState &PFS) {
       Loc = Lex.getLoc();
       return ParseTypeAndValue(V, PFS);
@@ -321,14 +321,13 @@ namespace llvm {
     // Function Parsing.
     struct ArgInfo {
       LocTy Loc;
-      PATypeHolder Type;
+      Type *Ty;
       unsigned Attrs;
       std::string Name;
-      ArgInfo(LocTy L, PATypeHolder Ty, unsigned Attr, const std::string &N)
-        : Loc(L), Type(Ty), Attrs(Attr), Name(N) {}
+      ArgInfo(LocTy L, Type *ty, unsigned Attr, const std::string &N)
+        : Loc(L), Ty(ty), Attrs(Attr), Name(N) {}
     };
-    bool ParseArgumentList(std::vector<ArgInfo> &ArgList,
-                           bool &isVarArg, bool inType);
+    bool ParseArgumentList(SmallVectorImpl<ArgInfo> &ArgList, bool &isVarArg);
     bool ParseFunctionHeader(Function *&Fn, bool isDefine);
     bool ParseFunctionBody(Function &Fn);
     bool ParseBasicBlock(PerFunctionState &PFS);