Create GDB pretty printer for offset_ptr, and implement the Unordered customization points

Author: k3DW

extra/boost_interprocess_printers.py

@@ -0,0 +1,43 @@
+# Copyright 2024 Braden Ganetsky
+# Distributed under the Boost Software License, Version 1.0.
+# https://www.boost.org/LICENSE_1_0.txt
+
+import gdb.printing
+
+class BoostInterprocessOffsetPtrPrinter:
+    def __init__(self, val):
+        self.val = val
+
+    def to_string(self):
+        return f"{BoostInterprocessOffsetPtrPrinter.get(self.val)}"
+
+    # This is a simplified and inlined version of `offset_ptr::get()`
+    def get(offset_ptr):
+        offset = offset_ptr["internal"]["m_offset"]
+        pointer = offset_ptr.type.template_argument(0).pointer()
+        if offset == 1:
+            return gdb.Value(0).cast(pointer) # nullptr
+        else:
+            unsigned_char_pointer = gdb.lookup_type("unsigned char").pointer()
+            this = offset_ptr.address
+            return (this.cast(unsigned_char_pointer) + offset).cast(pointer)
+
+    def boost_to_address(offset_ptr):
+        return BoostInterprocessOffsetPtrPrinter.get(offset_ptr)
+        
+    # This is a simplified and inlined version of `offset_ptr::operator+=()`
+    def boost_next(raw_ptr, offset):
+        unsigned_char_pointer = gdb.lookup_type("unsigned char").pointer()
+        pointer = raw_ptr.type
+        aa = raw_ptr.cast(unsigned_char_pointer)
+        bb = offset * pointer.target().sizeof
+        return (aa + bb).cast(pointer)
+
+def boost_interprocess_build_pretty_printer():
+    pp = gdb.printing.RegexpCollectionPrettyPrinter("boost_interprocess")
+
+    pp.add_printer("boost::interprocess::offset_ptr", "^boost::interprocess::offset_ptr<.*>$", BoostInterprocessOffsetPtrPrinter)
+
+    return pp
+
+gdb.printing.register_pretty_printer(gdb.current_objfile(), boost_interprocess_build_pretty_printer())

include/boost/interprocess/interprocess_printers.hpp

@@ -0,0 +1,66 @@
+// Copyright 2024 Braden Ganetsky
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+// Generated on 2024-08-16T22:13:13
+
+#ifndef BOOST_INTERPROCESS_INTERPROCESS_PRINTERS_HPP
+#define BOOST_INTERPROCESS_INTERPROCESS_PRINTERS_HPP
+
+#ifndef BOOST_ALL_NO_EMBEDDED_GDB_SCRIPTS
+#if defined(__ELF__)
+#ifdef __clang__
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Woverlength-strings"
+#endif
+__asm__(".pushsection \".debug_gdb_scripts\", \"MS\",@progbits,1\n"
+        ".ascii \"\\4gdb.inlined-script.BOOST_INTERPROCESS_INTERPROCESS_PRINTERS_HPP\\n\"\n"
+        ".ascii \"import gdb.printing\\n\"\n"
+
+        ".ascii \"class BoostInterprocessOffsetPtrPrinter:\\n\"\n"
+        ".ascii \"    def __init__(self, val):\\n\"\n"
+        ".ascii \"        self.val = val\\n\"\n"
+
+        ".ascii \"    def to_string(self):\\n\"\n"
+        ".ascii \"        return f\\\"{BoostInterprocessOffsetPtrPrinter.get(self.val)}\\\"\\n\"\n"
+
+        ".ascii \"    # This is a simplified and inlined version of `offset_ptr::get()`\\n\"\n"
+        ".ascii \"    def get(offset_ptr):\\n\"\n"
+        ".ascii \"        offset = offset_ptr[\\\"internal\\\"][\\\"m_offset\\\"]\\n\"\n"
+        ".ascii \"        pointer = offset_ptr.type.template_argument(0).pointer()\\n\"\n"
+        ".ascii \"        if offset == 1:\\n\"\n"
+        ".ascii \"            return gdb.Value(0).cast(pointer) # nullptr\\n\"\n"
+        ".ascii \"        else:\\n\"\n"
+        ".ascii \"            unsigned_char_pointer = gdb.lookup_type(\\\"unsigned char\\\").pointer()\\n\"\n"
+        ".ascii \"            this = offset_ptr.address\\n\"\n"
+        ".ascii \"            return (this.cast(unsigned_char_pointer) + offset).cast(pointer)\\n\"\n"
+
+        ".ascii \"    def boost_to_address(offset_ptr):\\n\"\n"
+        ".ascii \"        return BoostInterprocessOffsetPtrPrinter.get(offset_ptr)\\n\"\n"
+
+        ".ascii \"    # This is a simplified and inlined version of `offset_ptr::operator+=()`\\n\"\n"
+        ".ascii \"    def boost_next(raw_ptr, offset):\\n\"\n"
+        ".ascii \"        unsigned_char_pointer = gdb.lookup_type(\\\"unsigned char\\\").pointer()\\n\"\n"
+        ".ascii \"        pointer = raw_ptr.type\\n\"\n"
+        ".ascii \"        aa = raw_ptr.cast(unsigned_char_pointer)\\n\"\n"
+        ".ascii \"        bb = offset * pointer.target().sizeof\\n\"\n"
+        ".ascii \"        return (aa + bb).cast(pointer)\\n\"\n"
+
+        ".ascii \"def boost_interprocess_build_pretty_printer():\\n\"\n"
+        ".ascii \"    pp = gdb.printing.RegexpCollectionPrettyPrinter(\\\"boost_interprocess\\\")\\n\"\n"
+
+        ".ascii \"    pp.add_printer(\\\"boost::interprocess::offset_ptr\\\", \\\"^boost::interprocess::offset_ptr<.*>$\\\", BoostInterprocessOffsetPtrPrinter)\\n\"\n"
+
+        ".ascii \"    return pp\\n\"\n"
+
+        ".ascii \"gdb.printing.register_pretty_printer(gdb.current_objfile(), boost_interprocess_build_pretty_printer())\\n\"\n"
+
+        ".byte 0\n"
+        ".popsection\n");
+#ifdef __clang__
+#pragma clang diagnostic pop
+#endif
+#endif // defined(__ELF__)
+#endif // !defined(BOOST_ALL_NO_EMBEDDED_GDB_SCRIPTS)
+
+#endif // !defined(BOOST_INTERPROCESS_INTERPROCESS_PRINTERS_HPP)

include/boost/interprocess/offset_ptr.hpp

@@ -28,6 +28,7 @@
 #include <boost/type_traits/is_unsigned.hpp>
 
 #include <boost/interprocess/interprocess_fwd.hpp>
+#include <boost/interprocess/interprocess_printers.hpp>
 #include <boost/interprocess/detail/utilities.hpp>
 #include <boost/interprocess/detail/cast_tags.hpp>
 #include <boost/interprocess/detail/mpl.hpp>