[bindings/go] Add Go bindings to LLVMGetIndices

[aykevl]

Summary

This instruction is useful for inspecting extractvalue/insertvalue in IR. Unlike most other operations, indices cannot be inspected using the generic Value.Opcode() function so a specialized function needs to be added.

llvm/trunk/bindings/go/llvm/ir.go

func InlineAsm(t Type, asmString, constraints string, hasSideEffects, isAlignStack bool, dialect InlineAsmDialect) (rv Value) {
   casm := C.CString(asmString)
   defer C.free(unsafe.Pointer(casm))
   cconstraints := C.CString(constraints)
   defer C.free(unsafe.Pointer(cconstraints))
   rv.C = C.LLVMGetInlineAsm(t.C, casm, C.size_t(len(asmString)), cconstraints, C.size_t(len(constraints)), boolToLLVMBool(hasSideEffects), boolToLLVMBool(isAlignStack), C.LLVMInlineAsmDialect(dialect))
   return
 }
 
+// Operations on aggregates
+func (v Value) Indices() []uint32 {
+  num := C.LLVMGetNumIndices(v.C)
+  indicesPtr := C.LLVMGetIndices(v.C)
+  // https://github.com/golang/go/wiki/cgo#turning-c-arrays-into-go-slices
+  rawIndices := (*[1 << 30]C.uint)(unsafe.Pointer(indicesPtr))[:num:num]
+  indices := make([]uint32, num)
+  for i := range indices {
+    indices[i] = uint32(rawIndices[i])
+  }
+  return indices
+}
+
 //-------------------------------------------------------------------------
 // llvm.Builder
 //-------------------------------------------------------------------------
 
 // An instruction builder represents a point within a basic block, and is the
 // exclusive means of building instructions using the C interface.
 
 func (c Context) NewBuilder() (b Builder) { b.C = C.LLVMCreateBuilderInContext(c.C); return }