GDB: format output for class entries and class constants (php#15955)

For `zend_string` pointers in class entries, show the string contents (if not
`NULL`).

For class constants, the `ce` (class entry pointer) field is shown with the
name of the class, and the `doc_comment` field is shown with the string
contents if possible.

Author: DanielEScherzer

main/debug_gdb_scripts.c

@@ -737,6 +737,12 @@ asm(
     ".ascii \"\\n\"\n"
     ".ascii \"pp_set.add_printer('zend_string', '^_zend_string$', ZendStringPrettyPrinter)\\n\"\n"
     ".ascii \"\\n\"\n"
+    ".ascii \"def zendStringPointerPrinter(ptr):\\n\"\n"
+    ".ascii \"    \\\"Given a pointer to a zend_string, show the contents (if non-NULL)\\\"\\n\"\n"
+    ".ascii \"    if int(ptr) == 0:\\n\"\n"
+    ".ascii \"        return '0x0'\\n\"\n"
+    ".ascii \"    return ZendStringPrettyPrinter(ptr.dereference()).to_string()\\n\"\n"
+    ".ascii \"\\n\"\n"
     ".ascii \"class ZendTypePrettyPrinter(gdb.printing.PrettyPrinter):\\n\"\n"
     ".ascii \"    \\\"Print a zend_type\\\"\\n\"\n"
     ".ascii \"\\n\"\n"
@@ -959,6 +965,52 @@ asm(
     ".ascii \"\\n\"\n"
     ".ascii \"pp_set.add_printer('zval', '^_zval_struct$', ZvalPrettyPrinter)\\n\"\n"
     ".ascii \"\\n\"\n"
+    ".ascii \"class ZendClassEntryPrettyPrinter(gdb.printing.PrettyPrinter):\\n\"\n"
+    ".ascii \"    \\\"Print a zend_class_entry\\\"\\n\"\n"
+    ".ascii \"\\n\"\n"
+    ".ascii \"    # String pointers, show the string contents if possible\\n\"\n"
+    ".ascii \"    STRING_FIELDS = [ 'name', 'doc_comment' ]\\n\"\n"
+    ".ascii \"\\n\"\n"
+    ".ascii \"    def __init__(self, val):\\n\"\n"
+    ".ascii \"        self.val = val\\n\"\n"
+    ".ascii \"\\n\"\n"
+    ".ascii \"    def to_string(self):\\n\"\n"
+    ".ascii \"        return zendStringPointerPrinter(self.val['name'])\\n\"\n"
+    ".ascii \"\\n\"\n"
+    ".ascii \"    def children(self):\\n\"\n"
+    ".ascii \"        for field in self.val.type.fields():\\n\"\n"
+    ".ascii \"            if field.name is not None:\\n\"\n"
+    ".ascii \"                if field.name in self.STRING_FIELDS:\\n\"\n"
+    ".ascii \"                    yield (field.name, zendStringPointerPrinter(self.val[field.name]))\\n\"\n"
+    ".ascii \"                else:\\n\"\n"
+    ".ascii \"                    yield (field.name, self.val[field.name])\\n\"\n"
+    ".ascii \"            else:\\n\"\n"
+    ".ascii \"                # Don't break on the union fields. Unfortunately, pretty\\n\"\n"
+    ".ascii \"                # printers done in python cannot match the default formatting of\\n\"\n"
+    ".ascii \"                # C anonymous fields, which omit the name entirely, see\\n\"\n"
+    ".ascii \"                # binutils-gdb/gdb/cp-valprint.c#248 (as of commit\\n\"\n"
+    ".ascii \"                # b6532accdd8e24329cc69bb58bc2883796008776)\\n\"\n"
+    ".ascii \"                yield ('<anonymous>', self.val[field])\\n\"\n"
+    ".ascii \"\\n\"\n"
+    ".ascii \"pp_set.add_printer('zend_class_entry', '^_zend_class_entry$', ZendClassEntryPrettyPrinter)\\n\"\n"
+    ".ascii \"\\n\"\n"
+    ".ascii \"class ZendClassConstantPrettyPrinter(gdb.printing.PrettyPrinter):\\n\"\n"
+    ".ascii \"    \\\"Print a zend_class_constant\\\"\\n\"\n"
+    ".ascii \"\\n\"\n"
+    ".ascii \"    def __init__(self, val):\\n\"\n"
+    ".ascii \"        self.val = val\\n\"\n"
+    ".ascii \"\\n\"\n"
+    ".ascii \"    def children(self):\\n\"\n"
+    ".ascii \"        for field in self.val.type.fields():\\n\"\n"
+    ".ascii \"            if field.name == 'doc_comment':\\n\"\n"
+    ".ascii \"                yield ('doc_comment', zendStringPointerPrinter(self.val['doc_comment']))\\n\"\n"
+    ".ascii \"            elif field.name == 'ce':\\n\"\n"
+    ".ascii \"                yield ('ce', zendStringPointerPrinter(self.val['ce']['name']))\\n\"\n"
+    ".ascii \"            else:\\n\"\n"
+    ".ascii \"                yield (field.name, self.val[field.name])\\n\"\n"
+    ".ascii \"\\n\"\n"
+    ".ascii \"pp_set.add_printer('zend_class_constant', '^_zend_class_constant$', ZendClassConstantPrettyPrinter)\\n\"\n"
+    ".ascii \"\\n\"\n"
     ".ascii \"type_bit_to_name = None\\n\"\n"
     ".ascii \"type_name_to_bit = None\\n\"\n"
     ".ascii \"\\n\"\n"

scripts/gdb/php_gdb.py

@@ -67,6 +67,12 @@ def format_string(self):
 
 pp_set.add_printer('zend_string', '^_zend_string$', ZendStringPrettyPrinter)
 
+def zendStringPointerPrinter(ptr):
+    "Given a pointer to a zend_string, show the contents (if non-NULL)"
+    if int(ptr) == 0:
+        return '0x0'
+    return ZendStringPrettyPrinter(ptr.dereference()).to_string()
+
 class ZendTypePrettyPrinter(gdb.printing.PrettyPrinter):
     "Print a zend_type"
 
@@ -289,6 +295,52 @@ def children(self):
 
 pp_set.add_printer('zval', '^_zval_struct$', ZvalPrettyPrinter)
 
+class ZendClassEntryPrettyPrinter(gdb.printing.PrettyPrinter):
+    "Print a zend_class_entry"
+
+    # String pointers, show the string contents if possible
+    STRING_FIELDS = [ 'name', 'doc_comment' ]
+
+    def __init__(self, val):
+        self.val = val
+
+    def to_string(self):
+        return zendStringPointerPrinter(self.val['name'])
+
+    def children(self):
+        for field in self.val.type.fields():
+            if field.name is not None:
+                if field.name in self.STRING_FIELDS:
+                    yield (field.name, zendStringPointerPrinter(self.val[field.name]))
+                else:
+                    yield (field.name, self.val[field.name])
+            else:
+                # Don't break on the union fields. Unfortunately, pretty
+                # printers done in python cannot match the default formatting of
+                # C anonymous fields, which omit the name entirely, see
+                # binutils-gdb/gdb/cp-valprint.c#248 (as of commit
+                # b6532accdd8e24329cc69bb58bc2883796008776)
+                yield ('<anonymous>', self.val[field])
+
+pp_set.add_printer('zend_class_entry', '^_zend_class_entry$', ZendClassEntryPrettyPrinter)
+
+class ZendClassConstantPrettyPrinter(gdb.printing.PrettyPrinter):
+    "Print a zend_class_constant"
+
+    def __init__(self, val):
+        self.val = val
+
+    def children(self):
+        for field in self.val.type.fields():
+            if field.name == 'doc_comment':
+                yield ('doc_comment', zendStringPointerPrinter(self.val['doc_comment']))
+            elif field.name == 'ce':
+                yield ('ce', zendStringPointerPrinter(self.val['ce']['name']))
+            else:
+                yield (field.name, self.val[field.name])
+
+pp_set.add_printer('zend_class_constant', '^_zend_class_constant$', ZendClassConstantPrettyPrinter)
+
 type_bit_to_name = None
 type_name_to_bit = None