From 713658798dfafabcd0a74f510c1639f6e3c9c820 Mon Sep 17 00:00:00 2001
From: Maria Matejka <mq@ucw.cz>
Date: Wed, 23 Jan 2019 17:08:27 +0100
Subject: [PATCH] GDB pretty printers: f_inst and f_val.

---
 bird-gdb.py   | 84 +++++++++++++++++++++++++++++++++++++++++++++++++++
 lib/birdlib.h |  9 ++++++
 2 files changed, 93 insertions(+)
 create mode 100644 bird-gdb.py

diff --git a/bird-gdb.py b/bird-gdb.py
new file mode 100644
index 00000000..e91a633f
--- /dev/null
+++ b/bird-gdb.py
@@ -0,0 +1,84 @@
+class BIRDPrinter:
+    def __init__(self, val):
+        self.val = val
+
+    @classmethod
+    def lookup(cls, val):
+        if val.type.code != cls.typeCode:
+            return None
+        if val.type.tag != cls.typeTag:
+            return None
+
+        return cls(val)
+
+
+class BIRDFValPrinter(BIRDPrinter):
+    "Print BIRD\s struct f_val"
+    typeCode = gdb.TYPE_CODE_STRUCT
+    typeTag = "f_val"
+
+    codemap = {
+            "T_INT": "i",
+            "T_BOOL": "i",
+            "T_PAIR": "i",
+            "T_QUAD": "i",
+            "T_ENUM_RTS": "i",
+            "T_ENUM_BGP_ORIGIN": "i",
+            "T_ENUM_SCOPE": "i",
+            "T_ENUM_RTC": "i",
+            "T_ENUM_RTD": "i",
+            "T_ENUM_ROA": "i",
+            "T_ENUM_NETTYPE": "i",
+            "T_ENUM_RA_PREFERENCE": "i",
+            "T_IP": "ip",
+            "T_NET": "net",
+            "T_STRING": "s",
+            "T_PATH_MASK": "path_mask",
+            "T_PATH": "ad",
+            "T_CLIST": "ad",
+            "T_EC": "ec",
+            "T_ECLIST": "ad",
+            "T_LC": "lc",
+            "T_LCLIST": "ad",
+            "T_RD": "ec",
+            "T_PATH_MASK_ITEM": "pmi",
+            "T_SET": "t",
+            "T_PREFIX_SET": "ti",
+            }
+
+    def to_string(self):
+        code = self.val['type']
+        if code.type.code != gdb.TYPE_CODE_ENUM or code.type.tag != "f_type":
+            raise Exception("Strange 'type' element in f_val")
+
+        if str(code) == "T_VOID":
+            return "T_VOID"
+        else:
+            return "(%(c)s) %(v)s" % { "c": code, "v": self.val['val'][self.codemap[str(code)]] }
+
+    def display_hint(self):
+        return "map"
+
+class BIRDFInstPrinter(BIRDPrinter):
+    "Print BIRD's struct f_inst"
+    typeCode = gdb.TYPE_CODE_STRUCT
+    typeTag = "f_inst"
+
+    def to_string(self):
+        code = self.val['fi_code']
+        if str(code) == "FI_NOP":
+            return str(code) + ": " + str(self.val.cast(gdb.lookup_type("const char [%(siz)d]" % { "siz": self.val.type.sizeof })))
+        return str(code) + ": " + str(self.val['i_' + str(code)])
+
+# def children(self): # children iterator
+    def display_hint(self):
+        return "map"
+
+
+def register_printers(objfile):
+    objfile.pretty_printers.append(BIRDFInstPrinter.lookup)
+    objfile.pretty_printers.append(BIRDFValPrinter.lookup)
+
+register_printers(gdb.current_objfile())
+
+print("BIRD pretty printers loaded OK.")
diff --git a/lib/birdlib.h b/lib/birdlib.h
index 7cd78032..6fcc202f 100644
--- a/lib/birdlib.h
+++ b/lib/birdlib.h
@@ -164,6 +164,15 @@ void debug(const char *msg, ...);	/* Printf to debug output */
 #define ASSERT(x) do { if (!(x)) log(L_BUG "Assertion '%s' failed at %s:%d", #x, __FILE__, __LINE__); } while(0)
 #endif
 
+#ifdef DEBUGGING
+asm(
+    ".pushsection \".debug_gdb_scripts\", \"MS\",@progbits,1\n"
+    ".byte 1\n" /* Python */
+    ".asciz \"bird-gdb.py\"\n"
+    ".popsection\n"
+   );
+#endif
+
 /* Pseudorandom numbers */
 
 u32 random_u32(void);