From 227dda38a218e28ec2b5600599e1fcaf39cfd327 Mon Sep 17 00:00:00 2001
From: Li Jie <cpunion@gmail.com>
Date: Sat, 5 Oct 2024 17:46:54 +0800
Subject: [PATCH] lldb: fix slice index expression

---
 _lldb/llgo_plugin.py     | 23 ++++++++++++++++++++++-
 cl/_testdata/debug/in.go | 11 ++++++++++-
 2 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/_lldb/llgo_plugin.py b/_lldb/llgo_plugin.py
index 27ae8ad9..4643fe76 100644
--- a/_lldb/llgo_plugin.py
+++ b/_lldb/llgo_plugin.py
@@ -20,6 +20,27 @@ def is_llgo_compiler(_target: lldb.SBTarget) -> bool:
     return True
 
 
+def get_indexed_value(value: lldb.SBValue, index: int) -> Optional[lldb.SBValue]:
+    if not value or not value.IsValid():
+        return None
+
+    type_name = value.GetType().GetName()
+
+    if type_name.startswith('[]'):  # Slice
+        data_ptr = value.GetChildMemberWithName('data')
+        element_type = data_ptr.GetType().GetPointeeType()
+        element_size = element_type.GetByteSize()
+        ptr_value = int(data_ptr.GetValue(), 16)
+        element_address = ptr_value + index * element_size
+        target = value.GetTarget()
+        return target.CreateValueFromAddress(
+            f"element_{index}", lldb.SBAddress(element_address, target), element_type)
+    elif value.GetType().IsArrayType():  # Array
+        return value.GetChildAtIndex(index)
+    else:
+        return None
+
+
 def evaluate_expression(frame: lldb.SBFrame, expression: str) -> Optional[lldb.SBValue]:
     parts = re.findall(r'\*|\w+|\(|\)|\[.*?\]|\.', expression)
 
@@ -56,7 +77,7 @@ def evaluate_expression(frame: lldb.SBFrame, expression: str) -> Optional[lldb.S
                 i += 2
             elif part.startswith('['):
                 index = int(part[1:-1])
-                value = value.GetChildAtIndex(index)
+                value = get_indexed_value(value, index)
                 i += 1
             else:
                 if value is None:
diff --git a/cl/_testdata/debug/in.go b/cl/_testdata/debug/in.go
index 06c686ee..5840a92e 100644
--- a/cl/_testdata/debug/in.go
+++ b/cl/_testdata/debug/in.go
@@ -129,6 +129,15 @@ func FuncWithAllTypeParams(
 	//   slice: []int{21, 22, 23}
 	//   arr: [3]int{24, 25, 26}
 	//   arr2: [3]github.com/goplus/llgo/cl/_testdata/debug.E{{i = 27}, {i = 28}, {i = 29}}
+	//   slice[0]: 21
+	//   slice[1]: 22
+	//   slice[2]: 23
+	//   arr[0]: 24
+	//   arr[1]: 25
+	//   arr[2]: 26
+	//   arr2[0].i: 27
+	//   arr2[1].i: 28
+	//   arr2[2].i: 29
 	//   e: github.com/goplus/llgo/cl/_testdata/debug.E{i = 30}
 
 	// Expected(skip):
@@ -375,7 +384,7 @@ func ScopeIf(branch int) {
 		//   c: 3
 		//   d: 4
 		//   branch: 0
-		println(c, d)
+		println(a, c, d)
 	}
 	// Expected:
 	//   all variables: a branch