disas: Split disas.c

The routines in disas-common.c are also used from disas-mon.c.
Otherwise the rest of disassembly is only used from tcg.
While we're at it, put host and target code into separate files.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

disas/disas-target.c

@@ -0,0 +1,84 @@
+/*
+ * Routines for target instruction disassembly.
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "disas/disas.h"
+#include "disas/capstone.h"
+#include "disas-internal.h"
+
+
+void target_disas(FILE *out, CPUState *cpu, uint64_t code, size_t size)
+{
+    uint64_t pc;
+    int count;
+    CPUDebug s;
+
+    disas_initialize_debug_target(&s, cpu);
+    s.info.fprintf_func = fprintf;
+    s.info.stream = out;
+    s.info.buffer_vma = code;
+    s.info.buffer_length = size;
+    s.info.show_opcodes = true;
+
+    if (s.info.cap_arch >= 0 && cap_disas_target(&s.info, code, size)) {
+        return;
+    }
+
+    if (s.info.print_insn == NULL) {
+        s.info.print_insn = print_insn_od_target;
+    }
+
+    for (pc = code; size > 0; pc += count, size -= count) {
+        fprintf(out, "0x%08" PRIx64 ":  ", pc);
+        count = s.info.print_insn(pc, &s.info);
+        fprintf(out, "\n");
+        if (count < 0) {
+            break;
+        }
+        if (size < count) {
+            fprintf(out,
+                    "Disassembler disagrees with translator over instruction "
+                    "decoding\n"
+                    "Please report this to qemu-devel@nongnu.org\n");
+            break;
+        }
+    }
+}
+
+#ifdef CONFIG_PLUGIN
+static void plugin_print_address(bfd_vma addr, struct disassemble_info *info)
+{
+    /* does nothing */
+}
+
+/*
+ * We should only be dissembling one instruction at a time here. If
+ * there is left over it usually indicates the front end has read more
+ * bytes than it needed.
+ */
+char *plugin_disas(CPUState *cpu, uint64_t addr, size_t size)
+{
+    CPUDebug s;
+    GString *ds = g_string_new(NULL);
+
+    disas_initialize_debug_target(&s, cpu);
+    s.info.fprintf_func = disas_gstring_printf;
+    s.info.stream = (FILE *)ds;  /* abuse this slot */
+    s.info.buffer_vma = addr;
+    s.info.buffer_length = size;
+    s.info.print_address_func = plugin_print_address;
+
+    if (s.info.cap_arch >= 0 && cap_disas_plugin(&s.info, addr, size)) {
+        ; /* done */
+    } else if (s.info.print_insn) {
+        s.info.print_insn(addr, &s.info);
+    } else {
+        ; /* cannot disassemble -- return empty string */
+    }
+
+    /* Return the buffer, freeing the GString container.  */
+    return g_string_free(ds, false);
+}
+#endif /* CONFIG_PLUGIN */