[OCaml] Add OCaml API for LLVMGetIndices

[jberdine]

Summary

This patch adds a thin wrapper around LLVMGetNumIndices and
LLVMGetIndices to return the indices of ExtractValue or InsertValue
instructions as an OCaml array. It has not seemed to be necessary to
expose LLVMGetNumIndices separately.

[whitequark]

bindings/ocaml/llvm/llvm.mli

817

I think this function returns the indices, not the *number* of indices.

[whitequark]

bindings/ocaml/llvm/llvm_ocaml.c

738

Val_indices, by OCaml conventions, is the name for a function that makes an OCaml value from a C value indices, which is a bit confusing. Just indices would be nicer.

[jberdine]

fix doc, rename Val_indices

bindings/ocaml/llvm/llvm.mli

817

Indeed, nice catch.

bindings/ocaml/llvm/llvm.ml

let fold_right_uses f v init =
   aux (use_begin v) init
 
 
 (*--... Operations on users ................................................--*)
 external operand : llvalue -> int -> llvalue = "llvm_operand"
 external operand_use : llvalue -> int -> lluse = "llvm_operand_use"
 external set_operand : llvalue -> int -> llvalue -> unit = "llvm_set_operand"
 external num_operands : llvalue -> int = "llvm_num_operands"
+external indices : llvalue -> int array = "llvm_indices"
 
 (*--... Operations on constants of (mostly) any type .......................--*)
 external is_constant : llvalue -> bool = "llvm_is_constant"
 external const_null : lltype -> llvalue = "LLVMConstNull"
 external const_all_ones : (*int|vec*)lltype -> llvalue = "LLVMConstAllOnes"
 external const_pointer_null : lltype -> llvalue = "LLVMConstPointerNull"
 external undef : lltype -> llvalue = "LLVMGetUndef"
 external is_null : llvalue -> bool = "llvm_is_null"

bindings/ocaml/llvm/llvm.mli

(** [set_operand v i o] sets the operand of the value [v] at the index [i] to
     See the method [llvm::User::setOperand]. *)
 val set_operand : llvalue -> int -> llvalue -> unit
 
 (** [num_operands v] returns the number of operands for the value [v].
     See the method [llvm::User::getNumOperands]. *)
 val num_operands : llvalue -> int
 
 
+(** [indices i] returns the indices for the ExtractValue or InsertValue
+    instruction [i].
+    See the [llvm::getIndices] methods. *)
+val indices : llvalue -> int array
+
 (** {7 Operations on constants of (mostly) any type} *)
 
 (** [is_constant v] returns [true] if the value [v] is a constant, [false]
     otherwise. Similar to [llvm::isa<Constant>]. *)
 val is_constant : llvalue -> bool
 
 (** [const_null ty] returns the constant null (zero) of the type [ty].
     See the method [llvm::Constant::getNullValue]. *)

bindings/ocaml/llvm/llvm_ocaml.c

CAMLprim value llvm_set_operand(LLVMValueRef U, value I, LLVMValueRef V) {
   return Val_unit;
 }
 
 /* llvalue -> int */
 CAMLprim value llvm_num_operands(LLVMValueRef V) {
   return Val_int(LLVMGetNumOperands(V));
 }
 
+/* llvalue -> int array */
+CAMLprim value llvm_indices(LLVMValueRef Instr) {
+  CAMLparam0();
+  CAMLlocal1(indices);
+  unsigned n = LLVMGetNumIndices(Instr);
+  const unsigned *Indices = LLVMGetIndices(Instr);
+  indices = caml_alloc(n, 0);
+  for (unsigned i = 0; i < n; i++) {
+    Op_val(indices)[i] = Val_int(Indices[i]);
+  }
+  CAMLreturn(indices);
+}
+
 /*--... Operations on constants of (mostly) any type .......................--*/
 
 /* llvalue -> bool */
 CAMLprim value llvm_is_constant(LLVMValueRef Val) {
   return Val_bool(LLVMIsConstant(Val));
 }
 
 /* llvalue -> bool */