Add opaque ptr to the llvm-c

[deadalnix]

Summary

Add wrappers to allow use of opaque pointers from the C API

[deadalnix]

This is lacking a test. The LLVM C API is typically tested using the echo test (a program that read LLVM IR with the LLVM C API, and the re-emit it, and it can be checked that both are equal).

llvm/include/llvm-c/Core.h

1541

Considering that using things without context is deprecated, maybe we can skip this one.

[lerno]

Removed the default context method.

[lerno]

Note that I'm not really having a good environment to work on LLVM. I can submit changes I've tested to work with my frontend, but I don't know much about the unit tests in LLVM. If you don't want to accept this change because of the missing the tests, then perhaps we could have someone look at adding the tests?

[nikic]

This has been superseded by D125183.

llvm/include/llvm-c/Core.h

  * The created type will exist in the context that its pointee type
  * exists in.
  *
  * @see llvm::PointerType::get()
  */
 LLVMTypeRef LLVMPointerType(LLVMTypeRef ElementType, unsigned AddressSpace);
 
 /**
+ * Create an opaque pointer type in a context
+ *
+ * @see llvm::PointerType::get()
+ */
+LLVMTypeRef LLVMPointerTypeInContext(LLVMContextRef C, unsigned AddressSpace);
+
+/**
  * Obtain the address space of a pointer type.
  *
  * This only works on types that represent pointers.
  *
  * @see llvm::PointerType::getAddressSpace()
  */
 unsigned LLVMGetPointerAddressSpace(LLVMTypeRef PointerTy);
 

 /**
  * These are similar to the above functions except they operate on the
  * global context.
  */
 LLVMTypeRef LLVMVoidType(void);
 LLVMTypeRef LLVMLabelType(void);
 LLVMTypeRef LLVMX86MMXType(void);
 LLVMTypeRef LLVMX86AMXType(void);
 
 /**
  * @}
  */
 
 /**
  * @}
  */
 

llvm/lib/IR/Core.cpp

 }
 
 unsigned LLVMGetVectorSize(LLVMTypeRef VectorTy) {
   return unwrap<VectorType>(VectorTy)->getElementCount().getKnownMinValue();
 }
 
 /*--.. Operations on other types ...........................................--*/
 
+LLVMTypeRef LLVMPointerTypeInContext(LLVMContextRef C, unsigned AddressSpace)  {
+  return wrap(PointerType::get(*unwrap(C), AddressSpace));
+}
+
 LLVMTypeRef LLVMVoidTypeInContext(LLVMContextRef C)  {
   return wrap(Type::getVoidTy(*unwrap(C)));
 }
 LLVMTypeRef LLVMLabelTypeInContext(LLVMContextRef C) {
   return wrap(Type::getLabelTy(*unwrap(C)));
 }
 LLVMTypeRef LLVMTokenTypeInContext(LLVMContextRef C) {
   return wrap(Type::getTokenTy(*unwrap(C)));