Avoid fragile type lookups in GDB pretty printer

Instead of using the type llvm::StringMapEntry<{stringified_value_type}>
use only the base class llvm::StringMapEntryBase and calculate the
offsets of the member variables manually. The approach with stringifying
the name of the value type is pretty fragile as it can easily break with
local and dependent types.

Differential Revision: https://reviews.llvm.org/D94431
This commit is contained in:
Moritz Sichert 2021-01-11 15:55:20 +01:00
parent 2a8cbdd830
commit b46545542b

View File

@ -211,7 +211,7 @@ class StringMapPrinter:
it = self.val['TheTable']
end = (it + self.val['NumBuckets'])
value_ty = self.val.type.template_argument(0)
entry_ty = gdb.lookup_type('llvm::StringMapEntry<{}>'.format(value_ty.name))
entry_base_ty = gdb.lookup_type('llvm::StringMapEntryBase')
tombstone = gdb.parse_and_eval('llvm::StringMapImpl::TombstoneIntVal');
while it != end:
@ -220,15 +220,17 @@ class StringMapPrinter:
it = it + 1
continue
entry_ptr = it_deref.cast(entry_ty.pointer())
entry_ptr = it_deref.cast(entry_base_ty.pointer())
entry = entry_ptr.dereference()
str_len = entry['keyLength']
str_data = (entry_ptr + 1).cast(gdb.lookup_type('char').const().pointer())
value_ptr = (entry_ptr + 1).cast(value_ty.pointer())
str_data = (entry_ptr + 1).cast(gdb.lookup_type('uintptr_t')) + max(value_ty.sizeof, entry_base_ty.alignof)
str_data = str_data.cast(gdb.lookup_type('char').const().pointer())
string_ref = gdb.Value(struct.pack('PN', int(str_data), int(str_len)), gdb.lookup_type('llvm::StringRef'))
yield 'key', string_ref
value = entry['second']
value = value_ptr.dereference()
yield 'value', value
it = it + 1