From 1ecb94798ecbe5588c36c417d93d57bd93439fb3 Mon Sep 17 00:00:00 2001
From: Sergej Jaskiewicz <sergej.jaskiewicz@jetbrains.com>
Date: Wed, 15 Dec 2021 17:28:21 +0300
Subject: [PATCH] [lldb] Add a formatter for swift::Demangle::Node

---
 utils/lldb/lldbSwiftDataFormatters.py | 130 ++++++++++++++++++++++++++
 1 file changed, 130 insertions(+)

diff --git a/utils/lldb/lldbSwiftDataFormatters.py b/utils/lldb/lldbSwiftDataFormatters.py
index 17d5d2d0817bb..ccf484b2a00a3 100644
--- a/utils/lldb/lldbSwiftDataFormatters.py
+++ b/utils/lldb/lldbSwiftDataFormatters.py
@@ -5,12 +5,21 @@
 """
 
 import sys
+from enum import Enum
 
 
 def __lldb_init_module(debugger, internal_dict):
+    debugger.HandleCommand('type category define -e swift -l c++')
+
     tName = 'lldbSwiftDataFormatters.SmallBitVectorSummaryProvider'
     debugger.HandleCommand('type summary add -w llvm '
                            '-F %s -x "^llvm::SmallBitVector$"' % tName)
+    debugger.HandleCommand('type summary add --skip-references -w swift '
+                           '-F lldbSwiftDataFormatters.DemangleNodeSummaryProvider '
+                           '-x "^swift::Demangle::Node$"')
+    debugger.HandleCommand('type synthetic add --skip-references -w swift '
+                           '-l lldbSwiftDataFormatters.DemangleNodeSynthProvider '
+                           '-x "^swift::Demangle::Node$"')
 
 
 def SmallBitVectorSummaryProvider(valobj, internal_dict):
@@ -45,3 +54,124 @@ def SmallBitVectorSummaryProvider(valobj, internal_dict):
             res += '0'
     res += "]"
     return res
+
+
+class DemangleNodePayloadKind(Enum):
+    NONE = 0
+    TEXT = 1
+    INDEX = 2
+    ONE_CHILD = 3
+    TWO_CHILDREN = 4
+    MANY_CHILDREN = 5
+
+
+class DemangleNodeSynthProvider:
+    """ Provider for swift::Demangle::Node """
+
+    def __init__(self, valobj, internal_dict):
+        self.valobj = valobj
+        self.update()  # initialize this provider
+
+    def num_children(self):
+        if self.payload_kind in [DemangleNodePayloadKind.TEXT,
+                                 DemangleNodePayloadKind.INDEX,
+                                 DemangleNodePayloadKind.ONE_CHILD]:
+            return 2
+        if self.payload_kind is DemangleNodePayloadKind.TWO_CHILDREN:
+            return 3
+        if self.payload_kind is DemangleNodePayloadKind.MANY_CHILDREN:
+            return self.payload.GetChildMemberWithName('Children'). \
+                GetChildMemberWithName('Number').GetValueAsUnsigned() + 1
+        return 1
+
+    def get_child_index(self, name):
+        if name == 'NodeKind':
+            return 0
+
+        if self.payload_kind is DemangleNodePayloadKind.TEXT and name == 'Text':
+            return 1
+        if self.payload_kind is DemangleNodePayloadKind.INDEX and name == 'Index':
+            return 1
+        if self.payload_kind is DemangleNodePayloadKind.NONE:
+            return None
+        try:
+            return int(name.lstrip('[').rstrip(']')) + 1
+        except ValueError:
+            return None
+
+    def get_child_at_index(self, index):
+        if index == 0:
+            return self.valobj.GetChildMemberWithName('NodeKind')
+
+        index -= 1
+
+        if self.payload_kind is DemangleNodePayloadKind.TEXT and index == 0:
+            return self.payload.GetChildMemberWithName('Text')
+        if self.payload_kind is DemangleNodePayloadKind.INDEX and index == 0:
+            return self.payload.GetChildMemberWithName('Index')
+        if self.payload_kind is DemangleNodePayloadKind.ONE_CHILD \
+                and index == 0:
+            return self.payload \
+                .GetChildMemberWithName('InlineChildren') \
+                .GetChildAtIndex(0)
+        if self.payload_kind is DemangleNodePayloadKind.TWO_CHILDREN \
+                and 0 <= index <= 1:
+            return self.payload \
+                .GetChildMemberWithName('InlineChildren') \
+                .GetChildAtIndex(index)
+        if self.payload_kind is DemangleNodePayloadKind.MANY_CHILDREN \
+                and index >= 0:
+            node_vector = self.payload.GetChildMemberWithName('Children')
+            length = node_vector.GetChildMemberWithName('Number')
+            if index >= length.GetValueAsUnsigned():
+                return None
+            nodes_ptr = node_vector.GetChildMemberWithName('Nodes')
+            offset = self.node_ptr_size * index
+            return nodes_ptr.CreateChildAtOffset('[' + str(index) + ']',
+                                                 offset, self.node_ptr_type)
+        return None
+
+    def update(self):
+        self.payload_kind = DemangleNodePayloadKind(
+            self.valobj.GetChildMemberWithName('NodePayloadKind').GetValueAsUnsigned()
+        )
+        valobj_type = self.valobj.GetType()
+        if valobj_type.IsPointerType():
+            self.node_ptr_type = valobj_type
+        else:
+            self.node_ptr_type = valobj_type.GetPointerType()
+        self.node_ptr_size = self.node_ptr_type.GetByteSize()
+        self.payload = self.valobj.GetChildAtIndex(0)
+
+
+def DemangleNodeSummaryProvider(valobj, internal_dict):
+    valobj = valobj.GetNonSyntheticValue()
+    result = valobj.GetChildMemberWithName('NodeKind').GetValue()
+    result += ', '
+    payload_kind = DemangleNodePayloadKind(
+        valobj.GetChildMemberWithName('NodePayloadKind').GetValueAsUnsigned()
+    )
+    if payload_kind is DemangleNodePayloadKind.NONE:
+        result += '0 children'
+    if payload_kind is DemangleNodePayloadKind.TEXT:
+        result += 'Text='
+        result += valobj \
+            .GetChildAtIndex(0) \
+            .GetChildMemberWithName('Text') \
+            .GetSummary()
+    if payload_kind is DemangleNodePayloadKind.INDEX:
+        result += 'Index='
+        index = valobj \
+            .GetChildAtIndex(0) \
+            .GetChildMemberWithName('Index') \
+            .GetValueAsUnsigned()
+        result += str(index)
+    if payload_kind is DemangleNodePayloadKind.ONE_CHILD:
+        result += '1 child'
+    if payload_kind in [DemangleNodePayloadKind.TWO_CHILDREN,
+                        DemangleNodePayloadKind.MANY_CHILDREN]:
+        num_children = \
+            DemangleNodeSynthProvider(valobj, internal_dict).num_children() - 1
+        result += str(num_children)
+        result += ' children'
+    return result