[OpenCL] Clean up and add missing fields for block struct

Currently block is translated to a structure equivalent to

struct Block {
  void *isa;
  int flags;
  int reserved;
  void *invoke;
  void *descriptor;
};
Except invoke, which is the pointer to the block invoke function,
all other fields are useless for OpenCL, which clutter the IR and
also waste memory since the block struct is passed to the block
invoke function as argument.

On the other hand, the size and alignment of the block struct is
not stored in the struct, which causes difficulty to implement
__enqueue_kernel as library function, since the library function
needs to know the size and alignment of the argument which needs
to be passed to the kernel.

This patch removes the useless fields from the block struct and adds
size and align fields. The equivalent block struct will become

struct Block {
  int size;
  int align;
  generic void *invoke;
 /* custom fields */
};
It also changes the pointer to the invoke function to be
a generic pointer since the address space of a function
may not be private on certain targets.

Differential Revision: https://reviews.llvm.org/D37822


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@314932 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 22 insertions, 0 deletions

diff --git a/lib/CodeGen/TargetInfo.h b/lib/CodeGen/TargetInfo.h
index c26d7c710c..c9e5a400e4 100644
--- a/lib/CodeGen/TargetInfo.h
+++ b/lib/CodeGen/TargetInfo.h
@@ -37,6 +37,7 @@ namespace CodeGen {
 class ABIInfo;
 class CallArgList;
 class CodeGenFunction;
+class CGBlockInfo;
 class CGFunctionInfo;
 
 /// TargetCodeGenInfo - This class organizes various target-specific
@@ -265,6 +266,27 @@ public:
   /// Get the syncscope used in LLVM IR.
   virtual llvm::SyncScope::ID getLLVMSyncScopeID(SyncScope S,
                                                  llvm::LLVMContext &C) const;
+
+  /// Inteface class for filling custom fields of a block literal for OpenCL.
+  class TargetOpenCLBlockHelper {
+  public:
+    typedef std::pair<llvm::Value *, StringRef> ValueTy;
+    TargetOpenCLBlockHelper() {}
+    virtual ~TargetOpenCLBlockHelper() {}
+    /// Get the custom field types for OpenCL blocks.
+    virtual llvm::SmallVector<llvm::Type *, 1> getCustomFieldTypes() = 0;
+    /// Get the custom field values for OpenCL blocks.
+    virtual llvm::SmallVector<ValueTy, 1>
+    getCustomFieldValues(CodeGenFunction &CGF, const CGBlockInfo &Info) = 0;
+    virtual bool areAllCustomFieldValuesConstant(const CGBlockInfo &Info) = 0;
+    /// Get the custom field values for OpenCL blocks if all values are LLVM
+    /// constants.
+    virtual llvm::SmallVector<llvm::Constant *, 1>
+    getCustomFieldValues(CodeGenModule &CGM, const CGBlockInfo &Info) = 0;
+  };
+  virtual TargetOpenCLBlockHelper *getTargetOpenCLBlockHelper() const {
+    return nullptr;
+  }
 };
 
 } // namespace CodeGen