Unconditionally support block introspection data in a new field at the end

of the block descriptor field.  This field is the ObjC style @encode
signature of the implementation function, and was to this point
conditionally provided in the block literal data structure.  That
provisional support is removed.

Additionally, eliminate unused enumerations for the block literal flags field.
The first shipping ABI unconditionally set (1<<29) but this bit is unused
by the runtime, so the second ABI will unconditionally have (1<<30) set so
that the runtime can in fact distinguish whether the additional data is
present or not.

llvm-svn: 96989

4 files changed, 46 insertions, 56 deletions

diff --git a/clang/lib/CodeGen/CGBlocks.cpp b/clang/lib/CodeGen/CGBlocks.cpp
index c6c5d5a230c..7076067e438 100644
--- a/clang/lib/CodeGen/CGBlocks.cpp
+++ b/clang/lib/CodeGen/CGBlocks.cpp
@@ -24,7 +24,7 @@ using namespace clang;
 using namespace CodeGen;
 
 llvm::Constant *CodeGenFunction::
-BuildDescriptorBlockDecl(bool BlockHasCopyDispose, CharUnits Size,
+BuildDescriptorBlockDecl(const BlockExpr *BE, bool BlockHasCopyDispose, CharUnits Size,
                          const llvm::StructType* Ty,
                          std::vector<HelperInfo> *NoteForHelper) {
   const llvm::Type *UnsignedLongTy
@@ -43,6 +43,7 @@ BuildDescriptorBlockDecl(bool BlockHasCopyDispose, CharUnits Size,
   C = llvm::ConstantInt::get(UnsignedLongTy, Size.getQuantity());
   Elts.push_back(C);
 
+  // optional copy/dispose helpers
   if (BlockHasCopyDispose) {
     // copy_func_helper_decl
     Elts.push_back(BuildCopyHelper(Ty, NoteForHelper));
@@ -51,6 +52,17 @@ BuildDescriptorBlockDecl(bool BlockHasCopyDispose, CharUnits Size,
     Elts.push_back(BuildDestroyHelper(Ty, NoteForHelper));
   }
 
+  // Signature.  non-optional ObjC-style method descriptor @encode sequence
+  std::string BlockTypeEncoding;
+  CGM.getContext().getObjCEncodingForBlock(BE, BlockTypeEncoding);
+
+  Elts.push_back(llvm::ConstantExpr::getBitCast(
+          CGM.GetAddrOfConstantCString(BlockTypeEncoding), PtrToInt8Ty));
+  
+  // Layout.
+  C = llvm::ConstantInt::get(UnsignedLongTy, 0);
+  Elts.push_back(C);
+
   C = llvm::ConstantStruct::get(VMContext, Elts, false);
 
   C = new llvm::GlobalVariable(CGM.getModule(), C->getType(), true,
@@ -135,30 +147,14 @@ llvm::Value *CodeGenFunction::BuildBlockLiteralTmp(const BlockExpr *BE) {
 
   size_t BlockFields = 5;
 
-  bool hasIntrospection  = CGM.getContext().getLangOptions().BlockIntrospection;
-
-  if (hasIntrospection) {
-    BlockFields++;
-  }
   std::vector<llvm::Constant*> Elts(BlockFields);
 
-  if (hasIntrospection) {
-    std::string BlockTypeEncoding;
-    CGM.getContext().getObjCEncodingForBlock(BE, BlockTypeEncoding);
-
-    Elts[5] = llvm::ConstantExpr::getBitCast(
-            CGM.GetAddrOfConstantCString(BlockTypeEncoding), PtrToInt8Ty);
-  }
-
   llvm::Constant *C;
   llvm::Value *V;
 
   {
     // C = BuildBlockStructInitlist();
-    unsigned int flags = BLOCK_HAS_DESCRIPTOR;
-
-    if (hasIntrospection)
-      flags |= BLOCK_HAS_OBJC_TYPE;
+    unsigned int flags = BLOCK_HAS_OBJC_TYPE;
 
     // We run this first so that we set BlockHasCopyDispose from the entire
     // block literal.
@@ -199,7 +195,7 @@ llvm::Value *CodeGenFunction::BuildBlockLiteralTmp(const BlockExpr *BE) {
 
     if (subBlockDeclRefDecls.size() == 0) {
       // __descriptor
-      Elts[4] = BuildDescriptorBlockDecl(subBlockHasCopyDispose, subBlockSize,
+      Elts[4] = BuildDescriptorBlockDecl(BE, subBlockHasCopyDispose, subBlockSize,
                                          0, 0);
 
       // Optimize to being a global block.
@@ -221,8 +217,6 @@ llvm::Value *CodeGenFunction::BuildBlockLiteralTmp(const BlockExpr *BE) {
     for (int i=0; i<4; ++i)
       Types[i] = Elts[i]->getType();
     Types[4] = PtrToInt8Ty;
-    if (hasIntrospection)
-      Types[5] = PtrToInt8Ty;
 
     for (unsigned i=0; i < subBlockDeclRefDecls.size(); ++i) {
       const Expr *E = subBlockDeclRefDecls[i];
@@ -245,8 +239,6 @@ llvm::Value *CodeGenFunction::BuildBlockLiteralTmp(const BlockExpr *BE) {
 
     for (unsigned i=0; i<4; ++i)
       Builder.CreateStore(Elts[i], Builder.CreateStructGEP(V, i, "block.tmp"));
-    if (hasIntrospection)
-      Builder.CreateStore(Elts[5], Builder.CreateStructGEP(V, 5, "block.tmp"));
 
     for (unsigned i=0; i < subBlockDeclRefDecls.size(); ++i)
       {
@@ -335,7 +327,8 @@ llvm::Value *CodeGenFunction::BuildBlockLiteralTmp(const BlockExpr *BE) {
     NoteForHelper.resize(helpersize);
 
     // __descriptor
-    llvm::Value *Descriptor = BuildDescriptorBlockDecl(subBlockHasCopyDispose,
+    llvm::Value *Descriptor = BuildDescriptorBlockDecl(BE,
+                                                       subBlockHasCopyDispose,
                                                        subBlockSize, Ty,
                                                        &NoteForHelper);
     Descriptor = Builder.CreateBitCast(Descriptor, PtrToInt8Ty);
@@ -371,6 +364,16 @@ const llvm::Type *BlockModule::getBlockDescriptorType() {
   // struct __block_descriptor {
   //   unsigned long reserved;
   //   unsigned long block_size;
+  //
+  //   // later, the following will be added
+  //
+  //   struct {
+  //     void (*copyHelper)();
+  //     void (*copyHelper)();
+  //   } helpers;                // !!! optional
+  //
+  //   const char *signature;   // the block signature
+  //   const char *layout;      // reserved
   // };
   BlockDescriptorType = llvm::StructType::get(UnsignedLongTy->getContext(),
                                               UnsignedLongTy,
@@ -399,20 +402,8 @@ const llvm::Type *BlockModule::getGenericBlockLiteralType() {
   //   int __reserved;
   //   void (*__invoke)(void *);
   //   struct __block_descriptor *__descriptor;
-  //   // GNU runtime only:
-  //   const char *types;
   // };
-  if (CGM.getContext().getLangOptions().BlockIntrospection)
-    GenericBlockLiteralType = llvm::StructType::get(IntTy->getContext(),
-                                                  PtrToInt8Ty,
-                                                  IntTy,
-                                                  IntTy,
-                                                  PtrToInt8Ty,
-                                                  BlockDescPtrTy,
-                                                  PtrToInt8Ty,
-                                                  NULL);
-  else
-    GenericBlockLiteralType = llvm::StructType::get(IntTy->getContext(),
+  GenericBlockLiteralType = llvm::StructType::get(IntTy->getContext(),
                                                   PtrToInt8Ty,
                                                   IntTy,
                                                   IntTy,
@@ -556,7 +547,7 @@ BlockModule::GetAddrOfGlobalBlock(const BlockExpr *BE, const char * n) {
   const llvm::IntegerType *IntTy = cast<llvm::IntegerType>(
     getTypes().ConvertType(getContext().IntTy));
 
-  llvm::Constant *DescriptorFields[2];
+  llvm::Constant *DescriptorFields[4];
 
   // Reserved
   DescriptorFields[0] = llvm::Constant::getNullValue(UnsignedLongTy);
@@ -567,9 +558,21 @@ BlockModule::GetAddrOfGlobalBlock(const BlockExpr *BE, const char * n) {
     CGM.GetTargetTypeStoreSize(getGenericBlockLiteralType());
   DescriptorFields[1] =
     llvm::ConstantInt::get(UnsignedLongTy,BlockLiteralSize.getQuantity());
+  
+  // signature.  non-optional ObjC-style method descriptor @encode sequence
+  std::string BlockTypeEncoding;
+  CGM.getContext().getObjCEncodingForBlock(BE, BlockTypeEncoding);
+
+  DescriptorFields[2] = llvm::ConstantExpr::getBitCast(
+          CGM.GetAddrOfConstantCString(BlockTypeEncoding), PtrToInt8Ty);
+  
+  // layout
+  DescriptorFields[3] =
+    llvm::ConstantInt::get(UnsignedLongTy,0);
 
+  // build the structure from the 4 elements
   llvm::Constant *DescriptorStruct =
-    llvm::ConstantStruct::get(VMContext, &DescriptorFields[0], 2, false);
+    llvm::ConstantStruct::get(VMContext, &DescriptorFields[0], 4, false);
 
   llvm::GlobalVariable *Descriptor =
     new llvm::GlobalVariable(getModule(), DescriptorStruct->getType(), true,
@@ -578,8 +581,6 @@ BlockModule::GetAddrOfGlobalBlock(const BlockExpr *BE, const char * n) {
 
   int FieldCount = 5;
   // Generate the constants for the block literal.
-  if (CGM.getContext().getLangOptions().BlockIntrospection)
-    FieldCount = 6;
 
   std::vector<llvm::Constant*> LiteralFields(FieldCount);
 
@@ -602,10 +603,8 @@ BlockModule::GetAddrOfGlobalBlock(const BlockExpr *BE, const char * n) {
   LiteralFields[0] = getNSConcreteGlobalBlock();
 
   // Flags
-  LiteralFields[1] = CGM.getContext().getLangOptions().BlockIntrospection ?
-    llvm::ConstantInt::get(IntTy, BLOCK_IS_GLOBAL | BLOCK_HAS_DESCRIPTOR |
-            BLOCK_HAS_OBJC_TYPE) :
-    llvm::ConstantInt::get(IntTy, BLOCK_IS_GLOBAL | BLOCK_HAS_DESCRIPTOR);
+  LiteralFields[1] =
+    llvm::ConstantInt::get(IntTy, BLOCK_IS_GLOBAL | BLOCK_HAS_OBJC_TYPE);
 
   // Reserved
   LiteralFields[2] = llvm::Constant::getNullValue(IntTy);
@@ -616,14 +615,6 @@ BlockModule::GetAddrOfGlobalBlock(const BlockExpr *BE, const char * n) {
   // Descriptor
   LiteralFields[4] = Descriptor;
   
-  // Type encoding
-  if (CGM.getContext().getLangOptions().BlockIntrospection) {
-    std::string BlockTypeEncoding;
-    CGM.getContext().getObjCEncodingForBlock(BE, BlockTypeEncoding);
-
-    LiteralFields[5] = CGM.GetAddrOfConstantCString(BlockTypeEncoding);
-  }
-
   llvm::Constant *BlockLiteralStruct =
     llvm::ConstantStruct::get(VMContext, LiteralFields, false);
 
diff --git a/clang/lib/CodeGen/CGBlocks.h b/clang/lib/CodeGen/CGBlocks.h
index fc18c7cc564..39f26f8b136 100644
--- a/clang/lib/CodeGen/CGBlocks.h
+++ b/clang/lib/CodeGen/CGBlocks.h
@@ -54,7 +54,6 @@ public:
         BLOCK_HAS_COPY_DISPOSE =  (1 << 25),
         BLOCK_HAS_CXX_OBJ =       (1 << 26),
         BLOCK_IS_GLOBAL =         (1 << 28),
-        BLOCK_HAS_DESCRIPTOR =    (1 << 29),
         BLOCK_HAS_OBJC_TYPE  =    (1 << 30)
     };
 };
diff --git a/clang/lib/CodeGen/CodeGenFunction.h b/clang/lib/CodeGen/CodeGenFunction.h
index c4f0a9fcfff..64d5cbdb01a 100644
--- a/clang/lib/CodeGen/CodeGenFunction.h
+++ b/clang/lib/CodeGen/CodeGenFunction.h
@@ -465,7 +465,8 @@ public:
   //===--------------------------------------------------------------------===//
 
   llvm::Value *BuildBlockLiteralTmp(const BlockExpr *);
-  llvm::Constant *BuildDescriptorBlockDecl(bool BlockHasCopyDispose,
+  llvm::Constant *BuildDescriptorBlockDecl(const BlockExpr *,
+                                           bool BlockHasCopyDispose,
                                            CharUnits Size,
                                            const llvm::StructType *,
                                            std::vector<HelperInfo> *);
diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index d2391b391cd..145e29e7979 100644
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -1011,7 +1011,6 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
   // -fblocks=0 is default.
   if (Args.hasFlag(options::OPT_fblocks, options::OPT_fno_blocks,
                    getToolChain().IsBlocksDefault())) {
-    Args.AddLastArg(CmdArgs, options::OPT_fblock_introspection);
     CmdArgs.push_back("-fblocks");
   }