[committed] libstdc++: Add GDB printer for std::integral_constant
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Commit Message
I was finding it frustrating when returning from a function in GDB and
the return value was shown as $1 = { <no fields> }, so this makes it
print std::true_type or std::false_type.
There are some contexts where the output isn't ideal, e.g. a type
derived from std::true_type will now show something like:
$2 = {{std::integral_constant<bool, true> = std::true_type}};
But I think in most contexts it's an improvement.
Tested aarch64-linux, pushed to trunk.
-- >8 --
libstdc++-v3/ChangeLog:
* python/libstdcxx/v6/printers.py (StdIntegralConstantPrinter):
Add printer for std::integral_constant.
* testsuite/libstdc++-prettyprinters/cxx11.cc: Test it.
---
libstdc++-v3/python/libstdcxx/v6/printers.py | 20 +++++++++++++++++++
.../libstdc++-prettyprinters/cxx11.cc | 7 +++++++
2 files changed, 27 insertions(+)
@@ -2306,6 +2306,23 @@ class StdLocalePrinter(printer_base):
mod = ' with "{}={}"'.format(cat, other)
return 'std::locale = "{}"{}'.format(name, mod)
+class StdIntegralConstantPrinter(printer_base):
+ """Print a std::true_type or std::false_type."""
+
+ def __init__(self, typename, val):
+ self._val = val
+ self._typename = typename
+
+ def to_string(self):
+ value_type = self._val.type.template_argument(0)
+ value = self._val.type.template_argument(1)
+ if value_type.code == gdb.TYPE_CODE_BOOL:
+ if value:
+ return "std::true_type"
+ else:
+ return "std::false_type"
+ typename = strip_versioned_namespace(self._typename)
+ return "{}<{}, {}>".format(typename, value_type, value)
# A "regular expression" printer which conforms to the
# "SubPrettyPrinter" protocol from gdb.printing.
@@ -2788,6 +2805,9 @@ def build_libstdcxx_dictionary():
# vector<bool>
libstdcxx_printer.add_version('std::', 'locale', StdLocalePrinter)
+ libstdcxx_printer.add_version('std::', 'integral_constant',
+ StdIntegralConstantPrinter)
+
if hasattr(gdb.Value, 'dynamic_type'):
libstdcxx_printer.add_version('std::', 'error_code',
StdErrorCodePrinter)
@@ -207,6 +207,13 @@ main()
std::atomic<Value> av{{8, 9}};
// { dg-final { note-test av {std::atomic<Value> = { {i = 8, j = 9} }} } }
+ std::integral_constant<int, 1> one;
+ // { dg-final { note-test one {std::integral_constant<int, 1>} } }
+ std::integral_constant<bool, true> truth;
+ // { dg-final { note-test truth {std::true_type} } }
+ std::integral_constant<bool, 0> lies;
+ // { dg-final { note-test lies {std::false_type} } }
+
placeholder(""); // Mark SPOT
use(efl);
use(fl);