[CodeGen] Merge equivalent block copy/helper functions.

Clang generates copy and dispose helper functions for each block literal
on the stack. Often these functions are equivalent for different blocks.
This commit makes changes to merge equivalent copy and dispose helper
functions and reduce code size.

To enable merging equivalent copy/dispose functions, the captured object
infomation is encoded into the helper function name. This allows IRGen
to check whether an equivalent helper function has already been emitted
and reuse the function instead of generating a new helper function
whenever a block is defined. In addition, the helper functions are
marked as linkonce_odr to enable merging helper functions that have the
same name across translation units and marked as unnamed_addr to enable
the linker's deduplication pass to merge functions that have different
names but the same content.

rdar://problem/42640608

Differential Revision: https://reviews.llvm.org/D50152

llvm-svn: 339438

1 files changed, 24 insertions, 2 deletions

diff --git a/clang/lib/CodeGen/CodeGenFunction.h b/clang/lib/CodeGen/CodeGenFunction.h
index 878923a85bd..a160c368b19 100644
--- a/clang/lib/CodeGen/CodeGenFunction.h
+++ b/clang/lib/CodeGen/CodeGenFunction.h
@@ -1746,6 +1746,9 @@ public:
                                         bool IsLambdaConversionToBlock,
                                         bool BuildGlobalBlock);
 
+  /// Check if \p T is a C++ class that has a destructor that can throw.
+  static bool cxxDestructorCanThrow(QualType T);
+
   llvm::Constant *GenerateCopyHelperFunction(const CGBlockInfo &blockInfo);
   llvm::Constant *GenerateDestroyHelperFunction(const CGBlockInfo &blockInfo);
   llvm::Constant *GenerateObjCAtomicSetterCopyHelperFunction(
@@ -1754,7 +1757,8 @@ public:
                                              const ObjCPropertyImplDecl *PID);
   llvm::Value *EmitBlockCopyAndAutorelease(llvm::Value *Block, QualType Ty);
 
-  void BuildBlockRelease(llvm::Value *DeclPtr, BlockFieldFlags flags);
+  void BuildBlockRelease(llvm::Value *DeclPtr, BlockFieldFlags flags,
+                         bool CanThrow);
 
   class AutoVarEmission;
 
@@ -1777,7 +1781,7 @@ public:
   /// \param LoadBlockVarAddr Indicates whether we need to emit a load from
   /// \p Addr to get the address of the __block structure.
   void enterByrefCleanup(CleanupKind Kind, Address Addr, BlockFieldFlags Flags,
-                         bool LoadBlockVarAddr);
+                         bool LoadBlockVarAddr, bool CanThrow);
 
   void setBlockContextParameter(const ImplicitParamDecl *D, unsigned argNum,
                                 llvm::Value *ptr);
@@ -1800,6 +1804,11 @@ public:
 
   void GenerateCode(GlobalDecl GD, llvm::Function *Fn,
                     const CGFunctionInfo &FnInfo);
+
+  /// Annotate the function with an attribute that disables TSan checking at
+  /// runtime.
+  void markAsIgnoreThreadCheckingAtRuntime(llvm::Function *Fn);
+
   /// Emit code for the start of a function.
   /// \param Loc       The location to be associated with the function.
   /// \param StartLoc  The location of the function body.
@@ -3605,6 +3614,19 @@ public:
                                                CXXDtorType Type,
                                                const CXXRecordDecl *RD);
 
+  // Return the copy constructor name with the prefix "__copy_constructor_"
+  // removed.
+  static std::string getNonTrivialCopyConstructorStr(QualType QT,
+                                                     CharUnits Alignment,
+                                                     bool IsVolatile,
+                                                     ASTContext &Ctx);
+
+  // Return the destructor name with the prefix "__destructor_" removed.
+  static std::string getNonTrivialDestructorStr(QualType QT,
+                                                CharUnits Alignment,
+                                                bool IsVolatile,
+                                                ASTContext &Ctx);
+
   // These functions emit calls to the special functions of non-trivial C
   // structs.
   void defaultInitNonTrivialCStructVar(LValue Dst);