gdb/sim: add support for exporting memory map

This allows gdb to quickly dump & process the memory map that the sim
knows about.  This isn't fully accurate, but is largely limited by the
gdb memory map format.  While the sim supports RWX bits, gdb can only
handle RW or RO regions.

2 files changed, 61 insertions, 0 deletions

diff --git a/sim/common/ChangeLog b/sim/common/ChangeLog
index 0898a6f..05948f2 100644
--- a/sim/common/ChangeLog
+++ b/sim/common/ChangeLog
@@ -1,3 +1,7 @@
+2021-01-07  Mike Frysinger  <vapier@gentoo.org>
+
+	* sim-core.c (sim_memory_map): Define.
+
 2021-01-04  Mike Frysinger  <vapier@gentoo.org>
 
 	* acinclude.m4 (ACX_BUGURL): Change http:// to https://.
diff --git a/sim/common/sim-core.c b/sim/common/sim-core.c
index 74369aa..5382306 100644
--- a/sim/common/sim-core.c
+++ b/sim/common/sim-core.c
@@ -453,6 +453,63 @@ sim_core_translate (sim_core_mapping *mapping,
 
 
 #if EXTERN_SIM_CORE_P
+/* See include/gdb/remote-sim.h.  */
+char *
+sim_memory_map (SIM_DESC sd)
+{
+  sim_core *core = STATE_CORE (sd);
+  unsigned map;
+  char *s1, *s2, *entry;
+
+  s1 = xstrdup (
+    "<?xml version='1.0'?>\n"
+    "<!DOCTYPE memory-map PUBLIC '+//IDN gnu.org//DTD GDB Memory Map V1.0//EN'"
+    " 'http://sourceware.org/gdb/gdb-memory-map.dtd'>\n"
+    "<memory-map>\n");
+
+  for (map = 0; map < nr_maps; ++map)
+    {
+      sim_core_mapping *mapping;
+
+      for (mapping = core->common.map[map].first;
+	   mapping != NULL;
+	   mapping = mapping->next)
+	{
+	  /* GDB can only handle a single address space.  */
+	  if (mapping->level != 0)
+	    continue;
+
+	  entry = xasprintf ("<memory type='ram' start='%#x' length='%#x'/>\n",
+			     mapping->base, mapping->nr_bytes);
+	  /* The sim memory map is organized by access, not by addresses.
+	     So a RWX memory map will have three independent mappings.
+	     GDB's format cannot support overlapping regions, so we have
+	     to filter those out.
+
+	     Further, GDB can only handle RX ("rom") or RWX ("ram") mappings.
+	     We just emit "ram" everywhere to keep it simple.  If GDB ever
+	     gains support for more stuff, we can expand this.
+
+	     Using strstr is kind of hacky, but as long as the map is not huge
+	     (we're talking <10K), should be fine.  */
+	  if (strstr (s1, entry) == NULL)
+	    {
+	      s2 = concat (s1, entry, NULL);
+	      free (s1);
+	      s1 = s2;
+	    }
+	  free (entry);
+	}
+    }
+
+  s2 = concat (s1, "</memory-map>", NULL);
+  free (s1);
+  return s2;
+}
+#endif
+
+
+#if EXTERN_SIM_CORE_P
 unsigned
 sim_core_read_buffer (SIM_DESC sd,
 		      sim_cpu *cpu,