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, 18 insertions, 31 deletions

diff --git a/lib/CodeGen/ShadowStackGC.cpp b/lib/CodeGen/ShadowStackGC.cpp
index ff58b221cb..d7c9adad7f 100644
--- a/lib/CodeGen/ShadowStackGC.cpp
+++ b/lib/CodeGen/ShadowStackGC.cpp
@@ -45,7 +45,8 @@ namespace {
 
     /// StackEntryTy - Abstract type of a link in the shadow stack.
     ///
-    const StructType *StackEntryTy;
+    StructType *StackEntryTy;
+    StructType *FrameMapTy;
 
     /// Roots - GC roots in the current function. Each is a pair of the
     /// intrinsic call and its corresponding alloca.
@@ -211,18 +212,14 @@ Constant *ShadowStackGC::GetFrameMap(Function &F) {
   };
 
   Constant *DescriptorElts[] = {
-    ConstantStruct::get(StructType::get(Int32Ty, Int32Ty, NULL), BaseElts),
+    ConstantStruct::get(FrameMapTy, BaseElts),
     ConstantArray::get(ArrayType::get(VoidPtr, NumMeta), Metadata)
   };
 
-  Constant *FrameMap =
-    ConstantStruct::get(StructType::get(DescriptorElts[0]->getType(),
-                                        DescriptorElts[1]->getType(), NULL),
-                        DescriptorElts);
-
-  std::string TypeName("gc_map.");
-  TypeName += utostr(NumMeta);
-  F.getParent()->addTypeName(TypeName, FrameMap->getType());
+  Type *EltTys[] = { DescriptorElts[0]->getType(),DescriptorElts[1]->getType()};
+  StructType *STy = StructType::createNamed("gc_map."+utostr(NumMeta), EltTys);
+  
+  Constant *FrameMap = ConstantStruct::get(STy, DescriptorElts);
 
   // FIXME: Is this actually dangerous as WritingAnLLVMPass.html claims? Seems
   //        that, short of multithreaded LLVM, it should be safe; all that is
@@ -250,17 +247,12 @@ Constant *ShadowStackGC::GetFrameMap(Function &F) {
 
 const Type* ShadowStackGC::GetConcreteStackEntryType(Function &F) {
   // doInitialization creates the generic version of this type.
-  std::vector<const Type*> EltTys;
+  std::vector<Type*> EltTys;
   EltTys.push_back(StackEntryTy);
   for (size_t I = 0; I != Roots.size(); I++)
     EltTys.push_back(Roots[I].second->getAllocatedType());
-  Type *Ty = StructType::get(F.getContext(), EltTys);
-
-  std::string TypeName("gc_stackentry.");
-  TypeName += F.getName();
-  F.getParent()->addTypeName(TypeName, Ty);
-
-  return Ty;
+  
+  return StructType::createNamed("gc_stackentry."+F.getName().str(), EltTys);
 }
 
 /// doInitialization - If this module uses the GC intrinsics, find them now. If
@@ -271,13 +263,12 @@ bool ShadowStackGC::initializeCustomLowering(Module &M) {
   //   int32_t NumMeta;  // Number of metadata descriptors. May be < NumRoots.
   //   void *Meta[];     // May be absent for roots without metadata.
   // };
-  std::vector<const Type*> EltTys;
+  std::vector<Type*> EltTys;
   // 32 bits is ok up to a 32GB stack frame. :)
   EltTys.push_back(Type::getInt32Ty(M.getContext()));
   // Specifies length of variable length array. 
   EltTys.push_back(Type::getInt32Ty(M.getContext()));
-  StructType *FrameMapTy = StructType::get(M.getContext(), EltTys);
-  M.addTypeName("gc_map", FrameMapTy);
+  FrameMapTy = StructType::createNamed("gc_map", EltTys);
   PointerType *FrameMapPtrTy = PointerType::getUnqual(FrameMapTy);
 
   // struct StackEntry {
@@ -285,18 +276,14 @@ bool ShadowStackGC::initializeCustomLowering(Module &M) {
   //   FrameMap *Map;          // Pointer to constant FrameMap.
   //   void *Roots[];          // Stack roots (in-place array, so we pretend).
   // };
-  OpaqueType *RecursiveTy = OpaqueType::get(M.getContext());
-
+  
+  StackEntryTy = StructType::createNamed(M.getContext(), "gc_stackentry");
+  
   EltTys.clear();
-  EltTys.push_back(PointerType::getUnqual(RecursiveTy));
+  EltTys.push_back(PointerType::getUnqual(StackEntryTy));
   EltTys.push_back(FrameMapPtrTy);
-  PATypeHolder LinkTyH = StructType::get(M.getContext(), EltTys);
-
-  RecursiveTy->refineAbstractTypeTo(LinkTyH.get());
-  StackEntryTy = cast<StructType>(LinkTyH.get());
+  StackEntryTy->setBody(EltTys);
   const PointerType *StackEntryPtrTy = PointerType::getUnqual(StackEntryTy);
-  M.addTypeName("gc_stackentry", LinkTyH.get());  // FIXME: Is this safe from
-                                                  //        a FunctionPass?
 
   // Get the root chain if it already exists.
   Head = M.getGlobalVariable("llvm_gc_root_chain");
@@ -403,7 +390,7 @@ bool ShadowStackGC::performCustomLowering(Function &F) {
   Instruction *CurrentHead  = AtEntry.CreateLoad(Head, "gc_currhead");
   Instruction *EntryMapPtr  = CreateGEP(Context, AtEntry, StackEntry,
                                         0,1,"gc_frame.map");
-                              AtEntry.CreateStore(FrameMap, EntryMapPtr);
+  AtEntry.CreateStore(FrameMap, EntryMapPtr);
 
   // After all the allocas...
   for (unsigned I = 0, E = Roots.size(); I != E; ++I) {