Re: [patch] Add libstdc++ pretty printers for Library Fundamentals TS types

[Jonathan Wakely <jwakely at redhat dot com>]

On 14/07/14 20:31 +0100, Jonathan Wakely wrote:
> This adds printers for the types in the std::experimental namespace.

I've committed this slightly improved patch, which removes the
duplicate _contained method from StdExpOptionalPrinter (it was meant
to be using the base class version) and fixes some conditions to
compare to None, so that integers, booleans and pointers with zero
values don't get interpreted as no value.


commit f29d6b5d809df660a989dd19b8afe68d08934d9f
Author: redi <redi@138bc75d-0d04-0410-961f-82ee72b054a4>
Date:   Tue Jul 15 12:00:18 2014 +0000

    	* python/libstdcxx/v6/printers.py (SingleObjContainerPrinter): New
    	base class for experimental::any and experimental::optional printers.
    	(StdExpAnyPrinter, StdExpOptionalPrinter, StdExpStringViewPrinter):
    	New printers for Fundamentals TS types.
    	* testsuite/libstdc++-prettyprinters/libfundts.cc: New.
    
    git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@212556 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/libstdc++-v3/python/libstdcxx/v6/printers.py b/libstdc++-v3/python/libstdcxx/v6/printers.py
index ea34f22..af41f1f 100644
--- a/libstdc++-v3/python/libstdcxx/v6/printers.py
+++ b/libstdc++-v3/python/libstdcxx/v6/printers.py
@@ -836,6 +836,126 @@ class StdForwardListPrinter:
             return 'empty %s' % (self.typename)
         return '%s' % (self.typename)
 
+class SingleObjContainerPrinter(object):
+    "Base class for printers of containers of single objects"
+
+    def __init__ (self, val, viz):
+        self.contained_value = val
+        self.visualizer = viz
+
+    def _recognize(self, type):
+        """Return TYPE as a string after applying type printers"""
+        return gdb.types.apply_type_recognizers(gdb.types.get_type_recognizers(),
+                                                type) or str(type)
+
+    class _contained:
+        def __init__ (self, val):
+            self.val = val
+
+        def __iter__ (self):
+            return self
+
+        def next (self):
+            if self.val is None:
+                raise StopIteration
+            retval = self.val
+            self.val = None
+            return ('[contained value]', retval)
+
+    def children (self):
+        if self.contained_value is None:
+            return self._contained (None)
+        if hasattr (self.visualizer, 'children'):
+            return self.visualizer.children ()
+        return self._contained (self.contained_value)
+
+    def display_hint (self):
+        # if contained value is a map we want to display in the same way
+        if hasattr (self.visualizer, 'children') and hasattr (self.visualizer, 'display_hint'):
+            return self.visualizer.display_hint ()
+        return None
+
+
+class StdExpAnyPrinter(SingleObjContainerPrinter):
+    "Print a std::experimental::any"
+
+    def __init__ (self, typename, val):
+        self.typename = 'std::experimental::any'
+        self.val = val
+        self.contained_type = None
+        contained_value = None
+        visualizer = None
+        mgr = self.val['_M_manager']
+        if mgr != 0:
+            func = gdb.block_for_pc(int(mgr.cast(gdb.lookup_type('intptr_t'))))
+            if not func:
+                raise ValueError("Invalid function pointer in std::experimental::any")
+            rx = r"""({0}::_Manager_\w+<.*>)::_S_manage\({0}::_Op, {0} const\*, {0}::_Arg\*\)""".format(typename)
+            m = re.match(rx, func.function.name)
+            if not m:
+                raise ValueError("Unknown manager function in std::experimental::any")
+
+            # FIXME need to expand 'std::string' so that gdb.lookup_type works
+            mgrname = re.sub("std::string(?!\w)", gdb.lookup_type('std::string').strip_typedefs().name, m.group(1))
+            mgrtype = gdb.lookup_type(mgrname)
+            self.contained_type = mgrtype.template_argument(0)
+            valptr = None
+            if '::_Manager_internal' in mgrname:
+                valptr = self.val['_M_storage']['_M_buffer'].address
+            elif '::_Manager_external' in mgrname:
+                valptr = self.val['_M_storage']['_M_ptr']
+            elif '::_Manager_alloc' in mgrname:
+                datatype = gdb.lookup_type(mgrname + '::_Data')
+                valptr = self.val['_M_storage']['_M_ptr'].cast(datatype.pointer())
+                valptr = valptr.dereference()['_M_data'].address
+            else:
+                raise ValueError("Unknown manager function in std::experimental::any")
+            contained_value = valptr.cast(self.contained_type.pointer()).dereference()
+            visualizer = gdb.default_visualizer(contained_value)
+        super(StdExpAnyPrinter, self).__init__ (contained_value, visualizer)
+
+    def to_string (self):
+        if self.contained_type is None:
+            return '%s [no contained value]' % self.typename
+        desc = "%s containing " % self.typename
+        if hasattr (self.visualizer, 'children'):
+            return desc + self.visualizer.to_string ()
+        valtype = self._recognize (self.contained_type)
+        return desc + valtype
+
+class StdExpOptionalPrinter(SingleObjContainerPrinter):
+    "Print a std::experimental::optional"
+
+    def __init__ (self, typename, val):
+        valtype = self._recognize (val.type.template_argument(0))
+        self.typename = "std::experimental::optional<%s>" % valtype
+        self.val = val
+        contained_value = val['_M_payload'] if self.val['_M_engaged'] else None
+        visualizer = gdb.default_visualizer (val['_M_payload'])
+        super (StdExpOptionalPrinter, self).__init__ (contained_value, visualizer)
+
+    def to_string (self):
+        if self.contained_value is None:
+            return self.typename + " [no contained value]"
+        if hasattr (self.visualizer, 'children'):
+            return self.typename + " containing " + self.visualizer.to_string ()
+        return self.typename
+
+class StdExpStringViewPrinter:
+    "Print a std::experimental::basic_string_view"
+
+    def __init__ (self, typename, val):
+        self.val = val
+
+    def to_string (self):
+        ptr = self.val['_M_str']
+        len = self.val['_M_len']
+        if hasattr (ptr, "lazy_string"):
+            return ptr.lazy_string (length = len)
+        return ptr.string (length = len)
+
+    def display_hint (self):
+        return 'string'
 
 # A "regular expression" printer which conforms to the
 # "SubPrettyPrinter" protocol from gdb.printing.
@@ -865,12 +985,12 @@ class Printer(object):
         self.subprinters = []
         self.lookup = {}
         self.enabled = True
-        self.compiled_rx = re.compile('^([a-zA-Z0-9_:]+)<.*>$')
+        self.compiled_rx = re.compile('^([a-zA-Z0-9_:]+)(<.*>)?$')
 
     def add(self, name, function):
         # A small sanity check.
         # FIXME
-        if not self.compiled_rx.match(name + '<>'):
+        if not self.compiled_rx.match(name):
             raise ValueError('libstdc++ programming error: "%s" does not match' % name)
         printer = RxPrinter(name, function)
         self.subprinters.append(printer)
@@ -1214,6 +1334,13 @@ def build_libstdcxx_dictionary ():
     libstdcxx_printer.add('std::__debug::forward_list',
                           StdForwardListPrinter)
 
+    # Library Fundamentals TS components
+    libstdcxx_printer.add_version('std::experimental::fundamentals_v1::',
+                                  'any', StdExpAnyPrinter)
+    libstdcxx_printer.add_version('std::experimental::fundamentals_v1::',
+                                  'optional', StdExpOptionalPrinter)
+    libstdcxx_printer.add_version('std::experimental::fundamentals_v1::',
+                                  'basic_string_view', StdExpStringViewPrinter)
 
     # Extensions.
     libstdcxx_printer.add_version('__gnu_cxx::', 'slist', StdSlistPrinter)
diff --git a/libstdc++-v3/testsuite/libstdc++-prettyprinters/libfundts.cc b/libstdc++-v3/testsuite/libstdc++-prettyprinters/libfundts.cc
new file mode 100644
index 0000000..e2f99a1
--- /dev/null
+++ b/libstdc++-v3/testsuite/libstdc++-prettyprinters/libfundts.cc
@@ -0,0 +1,69 @@
+// { dg-do run }
+// { dg-options "-g -O0 -std=gnu++14" }
+
+// Copyright (C) 2014 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#include <experimental/any>
+#include <experimental/optional>
+#include <experimental/string_view>
+#include <string>
+#include <map>
+
+using std::experimental::any;
+using std::experimental::optional;
+using std::experimental::string_view;
+
+int
+main()
+{
+  string_view str = "string";
+// { dg-final { note-test str "\"string\"" } }
+
+  optional<int> o;
+// { dg-final { note-test o {std::experimental::optional<int> [no contained value]} } }
+  optional<bool> ob{false};
+// { dg-final { note-test ob {std::experimental::optional<bool> = {[contained value] = false}} } }
+  optional<int> oi{5};
+// { dg-final { note-test oi {std::experimental::optional<int> = {[contained value] = 5}} } }
+  optional<void*> op{nullptr};
+// { dg-final { note-test op {std::experimental::optional<void *> = {[contained value] = 0x0}} } }
+  optional<std::map<int, double>> om;
+  om = std::map<int, double>{ {1, 2.}, {3, 4.}, {5, 6.} };
+// { dg-final { note-test om {std::experimental::optional<std::map<int, double>> containing std::map with 3 elements = {[1] = 2, [3] = 4, [5] = 6}} } }
+  optional<std::string> os{ "stringy" };
+// { dg-final { note-test os {std::experimental::optional<std::string> = {[contained value] = "stringy"}} } }
+
+  any a;
+// { dg-final { note-test a {std::experimental::any [no contained value]} } }
+  any ab(false);
+// { dg-final { note-test ab {std::experimental::any containing bool = {[contained value] = false}} } }
+  any ai(6);
+// { dg-final { note-test ai {std::experimental::any containing int = {[contained value] = 6}} } }
+  any ap = (void*)nullptr;
+// { dg-final { note-test ap {std::experimental::any containing void * = {[contained value] = 0x0}} } }
+  any as = *os;
+// { dg-final { note-test as {std::experimental::any containing std::string = {[contained value] = "stringy"}} } }
+  any as2("stringiest");
+// { dg-final { regexp-test as2 {std::experimental::any containing const char \* = {\[contained value\] = 0x[[:xdigit:]]+ "stringiest"}} } }
+  any am = *om;
+// { dg-final { note-test am {std::experimental::any containing std::map with 3 elements = {[1] = 2, [3] = 4, [5] = 6}} } }
+
+  return 0;			// Mark SPOT
+}
+
+// { dg-final { gdb-test SPOT } }