From dabaf6d903591032a3bec7e30b777b7e3220f84f Mon Sep 17 00:00:00 2001
From: Patrick Wuttke <mewin@mewin.de>
Date: Fri, 10 Nov 2023 14:04:08 +0100
Subject: [PATCH] Added simple gdb pretty-printer (only StrideSpan and
 StrideSpanIterator for now).

---
 extra/gdb_pretty_printer.py | 86 +++++++++++++++++++++++++++++++++++++
 1 file changed, 86 insertions(+)
 create mode 100644 extra/gdb_pretty_printer.py

diff --git a/extra/gdb_pretty_printer.py b/extra/gdb_pretty_printer.py
new file mode 100644
index 0000000..8e1928d
--- /dev/null
+++ b/extra/gdb_pretty_printer.py
@@ -0,0 +1,86 @@
+
+import gdb
+import gdb.printing
+
+if hasattr(gdb, 'ValuePrinter'):
+    printer_base = gdb.ValuePrinter
+else:
+    printer_base = object
+
+
+class MijinStrideSpanIteratorPrinter(printer_base):
+    """Print a mijin::StrideSpanIterator."""
+    class _iterator:
+        def __init__(self, val):
+            self._val = val
+
+        def __iter__(self):
+            return self
+
+        def __next__(self):
+            if self._val is None:
+                raise StopIteration
+            self._val, val = None, self._val
+            return ('ele', val.dereference())
+
+    def __init__(self, val):
+        self._val = val
+
+    def children(self):
+        return self._iterator(self._val['ele_'])
+
+    def to_string(self):
+        t = self._val.type.template_argument(0)
+        return 'mijin::StrideSpanIterator<%s> with stride %d' % (str(t), self._val['strideBytes_'])
+
+    def display_hint(self):
+        return None # 'array'
+
+class MijinStrideSpanPrinter(printer_base):
+    """Print a mijin::StrideSpan."""
+
+    class _iterator:
+        def __init__(self, start, finish, stride_bytes):
+            self._stride_bytes = stride_bytes
+            self._item = start
+            self._finish = finish
+            self._count = 0
+
+        def __iter__(self):
+            return self
+
+        def __next__(self):
+            count = self._count
+            self._count = self._count + 1
+            if self._item == self._finish:
+                raise StopIteration
+            elt = self._item.dereference()
+            self._item = (self._item.cast(gdb.lookup_type('size_t')) + self._stride_bytes).cast(self._finish.type)
+            return ('[%d]' % count, elt)
+
+    def __init__(self, val):
+        self._typename = str(val.type)
+        self._val = val
+
+    def children(self):
+        return self._iterator(self._val['begin_'],
+                              self._val['end_'],
+                              self._val['strideBytes_'])
+
+    def to_string(self):
+        start = self._val['begin_']
+        finish = self._val['end_']
+        strideBytes = self._val['strideBytes_']
+        return ('%s of length %d, stride %d'
+                    % (self._typename, int(finish - start) / strideBytes, strideBytes))
+
+    def display_hint(self):
+        return 'array'
+
+def build_pretty_printer():
+    printer = gdb.printing.gdb.printing.RegexpCollectionPrettyPrinter('mijin_pp')
+    printer.add_printer('mijin::StrideSpan', r"^mijin::StrideSpan<.*>$", MijinStrideSpanPrinter)
+    printer.add_printer('mijin::StrideSpanIterator', r"^mijin::StrideSpanIterator<.*>$", MijinStrideSpanIteratorPrinter)
+    return printer
+
+gdb.printing.register_pretty_printer(gdb.current_objfile(), build_pretty_printer())
\ No newline at end of file