Treat the weak export of block runtime symbols as a deployment-target

feature akin to the ARC runtime checks.  Removes a terrible hack where
IR gen needed to find the declarations of those symbols in the translation
unit.

llvm-svn: 139404

6 files changed, 71 insertions, 90 deletions

diff --git a/clang/lib/CodeGen/CGBlocks.cpp b/clang/lib/CodeGen/CGBlocks.cpp
index b795ef1befc..fd93255e5c2 100644
--- a/clang/lib/CodeGen/CGBlocks.cpp
+++ b/clang/lib/CodeGen/CGBlocks.cpp
@@ -1809,3 +1809,58 @@ void CodeGenFunction::enterByrefCleanup(const AutoVarEmission &emission) {
 
   EHStack.pushCleanup<CallBlockRelease>(NormalAndEHCleanup, emission.Address);
 }
+
+/// Adjust the declaration of something from the blocks API.
+static void configureBlocksRuntimeObject(CodeGenModule &CGM,
+                                         llvm::Constant *C) {
+  if (!CGM.getLangOptions().BlocksRuntimeOptional) return;
+
+  llvm::GlobalValue *GV = cast<llvm::GlobalValue>(C->stripPointerCasts());
+  if (GV->isDeclaration() &&
+      GV->getLinkage() == llvm::GlobalValue::ExternalLinkage)
+    GV->setLinkage(llvm::GlobalValue::ExternalWeakLinkage);
+}
+
+llvm::Constant *CodeGenModule::getBlockObjectDispose() {
+  if (BlockObjectDispose)
+    return BlockObjectDispose;
+
+  llvm::Type *args[] = { Int8PtrTy, Int32Ty };
+  llvm::FunctionType *fty
+    = llvm::FunctionType::get(VoidTy, args, false);
+  BlockObjectDispose = CreateRuntimeFunction(fty, "_Block_object_dispose");
+  configureBlocksRuntimeObject(*this, BlockObjectDispose);
+  return BlockObjectDispose;
+}
+
+llvm::Constant *CodeGenModule::getBlockObjectAssign() {
+  if (BlockObjectAssign)
+    return BlockObjectAssign;
+
+  llvm::Type *args[] = { Int8PtrTy, Int8PtrTy, Int32Ty };
+  llvm::FunctionType *fty
+    = llvm::FunctionType::get(VoidTy, args, false);
+  BlockObjectAssign = CreateRuntimeFunction(fty, "_Block_object_assign");
+  configureBlocksRuntimeObject(*this, BlockObjectAssign);
+  return BlockObjectAssign;
+}
+
+llvm::Constant *CodeGenModule::getNSConcreteGlobalBlock() {
+  if (NSConcreteGlobalBlock)
+    return NSConcreteGlobalBlock;
+
+  NSConcreteGlobalBlock = GetOrCreateLLVMGlobal("_NSConcreteGlobalBlock",
+                                                Int8PtrTy->getPointerTo(), 0);
+  configureBlocksRuntimeObject(*this, NSConcreteGlobalBlock);
+  return NSConcreteGlobalBlock;
+}
+
+llvm::Constant *CodeGenModule::getNSConcreteStackBlock() {
+  if (NSConcreteStackBlock)
+    return NSConcreteStackBlock;
+
+  NSConcreteStackBlock = GetOrCreateLLVMGlobal("_NSConcreteStackBlock",
+                                               Int8PtrTy->getPointerTo(), 0);
+  configureBlocksRuntimeObject(*this, NSConcreteStackBlock);
+  return NSConcreteStackBlock;  
+}
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 7ccae084648..6df03c886fe 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -2396,93 +2396,3 @@ void CodeGenModule::EmitCoverageFile() {
     }
   }
 }
-
-///@name Custom Runtime Function Interfaces
-///@{
-//
-// FIXME: These can be eliminated once we can have clients just get the required
-// AST nodes from the builtin tables.
-
-llvm::Constant *CodeGenModule::getBlockObjectDispose() {
-  if (BlockObjectDispose)
-    return BlockObjectDispose;
-
-  DeclarationName DName(&Context.Idents.get("_Block_object_dispose"));
-  DeclContext::lookup_result
-    Lookup = Context.getTranslationUnitDecl()->lookup(DName);
-
-  // If there is an explicit decl, use that.
-  if (Lookup.first != Lookup.second)
-    if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(*Lookup.first))
-      return BlockObjectDispose =
-          GetAddrOfFunction(FD, getTypes().GetFunctionType(FD));
-
-  // Otherwise construct the function by hand.
-  llvm::Type *args[] = { Int8PtrTy, Int32Ty };
-  llvm::FunctionType *fty
-    = llvm::FunctionType::get(VoidTy, args, false);
-  return BlockObjectDispose =
-    CreateRuntimeFunction(fty, "_Block_object_dispose");
-}
-
-llvm::Constant *CodeGenModule::getBlockObjectAssign() {
-  if (BlockObjectAssign)
-    return BlockObjectAssign;
-
-  DeclarationName DName(&Context.Idents.get("_Block_object_assign"));
-  DeclContext::lookup_result
-    Lookup = Context.getTranslationUnitDecl()->lookup(DName);
-
-  // If there is an explicit decl, use that.
-  if (Lookup.first != Lookup.second)
-    if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(*Lookup.first))
-      return BlockObjectAssign =
-          GetAddrOfFunction(FD, getTypes().GetFunctionType(FD));
-
-  // Otherwise construct the function by hand.
-  llvm::Type *args[] = { Int8PtrTy, Int8PtrTy, Int32Ty };
-  llvm::FunctionType *fty
-    = llvm::FunctionType::get(VoidTy, args, false);
-  return BlockObjectAssign =
-    CreateRuntimeFunction(fty, "_Block_object_assign");
-}
-
-llvm::Constant *CodeGenModule::getNSConcreteGlobalBlock() {
-  if (NSConcreteGlobalBlock)
-    return NSConcreteGlobalBlock;
-
-  DeclarationName DName(&Context.Idents.get("_NSConcreteGlobalBlock"));
-  DeclContext::lookup_result
-    Lookup = Context.getTranslationUnitDecl()->lookup(DName);
-
-  // If there is an explicit decl, use that.
-  if (Lookup.first != Lookup.second)
-    if (const VarDecl *VD = dyn_cast<VarDecl>(*Lookup.first))
-      return NSConcreteGlobalBlock =
-          GetAddrOfGlobalVar(VD, getTypes().ConvertType(VD->getType()));
-
-  // Otherwise construct the variable by hand.
-  return NSConcreteGlobalBlock =
-    CreateRuntimeVariable(Int8PtrTy, "_NSConcreteGlobalBlock");
-}
-
-llvm::Constant *CodeGenModule::getNSConcreteStackBlock() {
-  if (NSConcreteStackBlock)
-    return NSConcreteStackBlock;
-
-  DeclarationName DName(&Context.Idents.get("_NSConcreteStackBlock"));
-  DeclContext::lookup_result
-    Lookup = Context.getTranslationUnitDecl()->lookup(DName);
-
-  // If there is an explicit decl, use that.
-  if (Lookup.first != Lookup.second)
-    if (const VarDecl *VD = dyn_cast<VarDecl>(*Lookup.first))
-      return NSConcreteStackBlock =
-          GetAddrOfGlobalVar(VD, getTypes().ConvertType(VD->getType()));
-
-  // Otherwise construct the variable by hand.
-  return NSConcreteStackBlock =
-    CreateRuntimeVariable(Int8PtrTy, "_NSConcreteStackBlock");
-}
-
-///@}
diff --git a/clang/lib/Driver/ToolChains.cpp b/clang/lib/Driver/ToolChains.cpp
index 7b5183c1066..bcd540084dc 100644
--- a/clang/lib/Driver/ToolChains.cpp
+++ b/clang/lib/Driver/ToolChains.cpp
@@ -109,6 +109,14 @@ void Darwin::configureObjCRuntime(ObjCRuntime &runtime) const {
     runtime.HasTerminate = false;
 }
 
+/// Darwin provides a blocks runtime starting in MacOS X 10.6 and iOS 3.2.
+bool Darwin::hasBlocksRuntime() const {
+  if (isTargetIPhoneOS())
+    return !isIPhoneOSVersionLT(3, 2);
+  else
+    return !isMacosxVersionLT(10, 6);
+}
+
 // FIXME: Can we tablegen this?
 static const char *GetArmArchForMArch(StringRef Value) {
   if (Value == "armv6k")
diff --git a/clang/lib/Driver/ToolChains.h b/clang/lib/Driver/ToolChains.h
index cfb8869f47e..10c416a5fb9 100644
--- a/clang/lib/Driver/ToolChains.h
+++ b/clang/lib/Driver/ToolChains.h
@@ -187,6 +187,7 @@ public:
   virtual bool HasNativeLLVMSupport() const;
 
   virtual void configureObjCRuntime(ObjCRuntime &runtime) const;
+  virtual bool hasBlocksRuntime() const;
 
   virtual DerivedArgList *TranslateArgs(const DerivedArgList &Args,
                                         const char *BoundArch) const;
diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index 3158a517fbd..691e96cb115 100644
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -1718,6 +1718,10 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
          Args.hasArg(options::OPT_fobjc_nonfragile_abi) &&
          !Args.hasArg(options::OPT_fno_blocks))) {
     CmdArgs.push_back("-fblocks");
+
+    if (!Args.hasArg(options::OPT_fgnu_runtime) && 
+        !getToolChain().hasBlocksRuntime())
+      CmdArgs.push_back("-fblocks-runtime-optional");
   }
 
   // -faccess-control is default.
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 426db565873..7ea31613bd3 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -665,6 +665,8 @@ static void LangOptsToArgs(const LangOptions &Opts,
     Res.push_back("-pthread");
   if (Opts.Blocks)
     Res.push_back("-fblocks");
+  if (Opts.BlocksRuntimeOptional)
+    Res.push_back("-fblocks-runtime-optional");
   if (Opts.EmitAllDecls)
     Res.push_back("-femit-all-decls");
   if (Opts.MathErrno)
@@ -1667,6 +1669,7 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
 
   Opts.RTTI = !Args.hasArg(OPT_fno_rtti);
   Opts.Blocks = Args.hasArg(OPT_fblocks);
+  Opts.BlocksRuntimeOptional = Args.hasArg(OPT_fblocks_runtime_optional);
   Opts.CharIsSigned = !Args.hasArg(OPT_fno_signed_char);
   Opts.ShortWChar = Args.hasArg(OPT_fshort_wchar);
   Opts.ShortEnums = Args.hasArg(OPT_fshort_enums);