Generate a Builder data type. WIP.

The Builder provides a convenient interface for inserting instructions
into an extended basic block.

The bulk of the builder methods are generated automatically from the
meta language instruction descriptions.

Still TODO: Keep track of an insertion position.

src/libcretonne/ir/builder.rs

@@ -0,0 +1,27 @@
+//! Cretonne instruction builder.
+//!
+//! A `Builder` provides a convenient interface for inserting instructions into a Cretonne
+//! function. Many of its methods are generated from the meta language instruction definitions.
+
+use ir::{types, instructions};
+use ir::{InstructionData, DataFlowGraph};
+use ir::{Opcode, Type, Inst, Value, Ebb, JumpTable, VariableArgs, FuncRef};
+use ir::immediates::{Imm64, Uimm8, Ieee32, Ieee64, ImmVector};
+use ir::condcodes::{IntCC, FloatCC};
+
+pub struct Builder<'a> {
+    dfg: &'a mut DataFlowGraph,
+}
+
+impl<'a> Builder<'a> {
+    // Create and insert an instruction.
+    // This method is used by the generated format-specific methods.
+    fn insert_inst(&mut self, data: InstructionData) -> Inst {
+        let inst = self.dfg.make_inst(data);
+        inst
+    }
+}
+
+// Include code generated by `meta/gen_instr.py`. This file includes `Builder` methods per
+// instruction format and per opcode for inserting instructions.
+include!(concat!(env!("OUT_DIR"), "/builder.rs"));