tcg: Add tcg_set_insn_param

Add tcg_set_insn_param as a mechanism to modify an insn
parameter after emiting the insn. This is useful for icount
and also for embedding fault information for a specific insn.
Reviewed-by: NRichard Henderson <rth@twiddle.net>
Signed-off-by: NEdgar E. Iglesias <edgar.iglesias@xilinx.com>
Message-id: 1461931684-1867-2-git-send-email-edgar.iglesias@gmail.com
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

tcg/tcg.h

@@ -595,6 +595,12 @@ struct TCGContext {
 
 extern TCGContext tcg_ctx;
 
+static inline void tcg_set_insn_param(int op_idx, int arg, TCGArg v)
+{
+    int op_argi = tcg_ctx.gen_op_buf[op_idx].args;
+    tcg_ctx.gen_opparam_buf[op_argi + arg] = v;
+}
+
 /* The number of opcodes emitted so far.  */
 static inline int tcg_op_buf_count(void)
 {