From 0ce7d86d6a53b38ed75045173da33b277415254d Mon Sep 17 00:00:00 2001
From: Tamas Koczka <poprdi@google.com>
Date: Wed, 28 Jan 2026 14:34:43 +0000
Subject: pkg/codesearch: expose struct layout in codesearch

- Extract struct field offsets and sizes in the C++ codesearch indexer.
- Add 'fields' to the JSON definition output.
- Update pkg/codesearch to parse and expose the new field information.
- Add 'struct-layout' command to syz-codesearch for debugging.
- Add 'codesearch-struct-layout' tool to pkg/aflow/tool/codesearcher/
to allow LLM agents to query struct memory layout and map byte offsets to fields.
- Support pointer marshaling for optional JSON values (e.g. *uint)
---
 .../testdata/query-struct-layout-some-struct       |  5 ++
 .../query-struct-layout-some-struct-offset         |  4 ++
 .../testdata/query-struct-layout-some-union        |  6 ++
 pkg/codesearch/testdata/source0.c.json             | 70 ++++++++++++++++++++--
 4 files changed, 80 insertions(+), 5 deletions(-)
 create mode 100644 pkg/codesearch/testdata/query-struct-layout-some-struct
 create mode 100644 pkg/codesearch/testdata/query-struct-layout-some-struct-offset
 create mode 100644 pkg/codesearch/testdata/query-struct-layout-some-union

(limited to 'pkg/codesearch/testdata')

diff --git a/pkg/codesearch/testdata/query-struct-layout-some-struct b/pkg/codesearch/testdata/query-struct-layout-some-struct
new file mode 100644
index 000000000..a7d8e418e
--- /dev/null
+++ b/pkg/codesearch/testdata/query-struct-layout-some-struct
@@ -0,0 +1,5 @@
+struct-layout testdata/source0.h some_struct
+
+struct some_struct has 2 fields:
+[0 - 32] x
+[32 - 64] y
diff --git a/pkg/codesearch/testdata/query-struct-layout-some-struct-offset b/pkg/codesearch/testdata/query-struct-layout-some-struct-offset
new file mode 100644
index 000000000..8aa337e87
--- /dev/null
+++ b/pkg/codesearch/testdata/query-struct-layout-some-struct-offset
@@ -0,0 +1,4 @@
+struct-layout testdata/source0.h some_struct 0
+
+struct some_struct has 1 fields:
+[0 - 32] x
diff --git a/pkg/codesearch/testdata/query-struct-layout-some-union b/pkg/codesearch/testdata/query-struct-layout-some-union
new file mode 100644
index 000000000..a5891ae6b
--- /dev/null
+++ b/pkg/codesearch/testdata/query-struct-layout-some-union
@@ -0,0 +1,6 @@
+struct-layout testdata/source0.h some_union
+
+struct some_union has 3 fields:
+[0 - 32] x
+[0 - 64] p
+[0 - 64] s
diff --git a/pkg/codesearch/testdata/source0.c.json b/pkg/codesearch/testdata/source0.c.json
index 451ab58cc..39e4b6775 100644
--- a/pkg/codesearch/testdata/source0.c.json
+++ b/pkg/codesearch/testdata/source0.c.json
@@ -192,7 +192,14 @@
 				"start_line": 36,
 				"end_line": 38
 			},
-			"comment": {}
+			"comment": {},
+			"fields": [
+				{
+					"name": "x",
+					"offset": 0,
+					"size": 32
+				}
+			]
 		},
 		{
 			"name": "some_struct",
@@ -202,7 +209,19 @@
 				"start_line": 17,
 				"end_line": 20
 			},
-			"comment": {}
+			"comment": {},
+			"fields": [
+				{
+					"name": "x",
+					"offset": 0,
+					"size": 32
+				},
+				{
+					"name": "y",
+					"offset": 32,
+					"size": 32
+				}
+			]
 		},
 		{
 			"name": "some_struct_with_a_comment",
@@ -216,7 +235,19 @@
 				"file": "source0.h",
 				"start_line": 24,
 				"end_line": 26
-			}
+			},
+			"fields": [
+				{
+					"name": "x",
+					"offset": 0,
+					"size": 32
+				},
+				{
+					"name": "other_struct",
+					"offset": 64,
+					"size": 64
+				}
+			]
 		},
 		{
 			"name": "struct_in_c_file",
@@ -226,7 +257,19 @@
 				"start_line": 6,
 				"end_line": 9
 			},
-			"comment": {}
+			"comment": {},
+			"fields": [
+				{
+					"name": "X",
+					"offset": 0,
+					"size": 32
+				},
+				{
+					"name": "by_value",
+					"offset": 32,
+					"size": 64
+				}
+			]
 		},
 		{
 			"name": "some_union",
@@ -236,7 +279,24 @@
 				"start_line": 40,
 				"end_line": 44
 			},
-			"comment": {}
+			"comment": {},
+			"fields": [
+				{
+					"name": "x",
+					"offset": 0,
+					"size": 32
+				},
+				{
+					"name": "p",
+					"offset": 0,
+					"size": 64
+				},
+				{
+					"name": "s",
+					"offset": 0,
+					"size": 64
+				}
+			]
 		},
 		{
 			"name": "some_enum",
-- 
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