Use genrule to pull in bindgen-erated source

Rather than having a local modification of the upstream Rust source,
instead use a genrule to replace the `${INCLUDES}` placeholder with
a re-export of everything from the bindgen-created code.

This change means that the upstream BoringSSL source no longer has a
local modification, making it easier to import new versions.

Also add a rust_test for the bindgen layout tests along the way.

Bug: 177080016
Test: build targets, atest libbssl_sys_raw_test
Change-Id: Iabf1b6ac4ae7d3a391cc038b29f157347fb36f2f
Merged-In: Iabf1b6ac4ae7d3a391cc038b29f157347fb36f2f
(cherry picked from commit 71257a0a0347296eba49f1ca39c0e6b024243ffb)
(cherry picked from commit 1364953c681d19461b5bf3f291cc336c1ec0f625)
Merged-In: Iabf1b6ac4ae7d3a391cc038b29f157347fb36f2f

3 files changed, 33 insertions, 2 deletions

diff --git a/Android.bp b/Android.bp
index 99617760..40acf086 100644
--- a/Android.bp
+++ b/Android.bp
@@ -576,6 +576,8 @@ rust_bindgen {
     wrapper_src: "src/rust/wrapper.h",
     vendor_available: true,
     bindgen_flags: [
+        // Adapted from upstream the src/rust/CMakeLists.txt file at:
+        // https://boringssl.googlesource.com/boringssl/+/refs/heads/master/rust/CMakeLists.txt
         "--no-derive-default",
         "--enable-function-attribute-detection",
         "--use-core",
@@ -603,6 +605,21 @@ rust_bindgen {
     ],
 }
 
+// Encapsulate the bindgen-generated layout tests as a test target.
+rust_test {
+    name: "libbssl_sys_raw_test",
+    srcs: [
+        ":libbssl_sys_raw",
+    ],
+    crate_name: "bssl_sys_raw_test",
+    test_suites: ["general-tests"],
+    auto_gen_config: true,
+    clippy_lints: "none",
+    lints: "none",
+}
+
+// Rust's bindgen doesn't cope with macros, so this target includes C functions that
+// do the same thing as macros defined in BoringSSL header files.
 cc_library_static {
     name: "libbssl_rust_support",
     host_supported: true,
@@ -614,6 +631,13 @@ cc_library_static {
     ],
 }
 
+// Replace the upstream CMake placeholder with a re-export of all of the local bindgen output.
+gensrcs {
+    name: "libbssl_sys_src",
+    srcs: ["src/rust/src/lib.rs"],
+    cmd: "sed 's@^.{INCLUDES}@pub use bssl_sys_raw::*;@' $(in) > $(out)",
+}
+
 rust_library {
     name: "libbssl_ffi",
     host_supported: true,
diff --git a/TEST_MAPPING b/TEST_MAPPING
new file mode 100644
index 00000000..ce976386
--- /dev/null
+++ b/TEST_MAPPING
@@ -0,0 +1,7 @@
+{
+  "presubmit": [
+    {
+      "name": "libbssl_sys_raw_test"
+    }
+  ]
+}
diff --git a/src/rust/src/lib.rs b/src/rust/src/lib.rs
index b691baba..d8c2c000 100644
--- a/src/rust/src/lib.rs
+++ b/src/rust/src/lib.rs
@@ -2,8 +2,8 @@
 #![allow(non_camel_case_types)]
 #![allow(non_snake_case)]
 
-// ANDROID: Use Soong-generated bindings rather than CMake-generated
-pub use bssl_sys_raw::*;
+// populated by cmake
+${INCLUDES}
 
 pub fn ERR_GET_LIB(packed_error: u32) -> i32 {
     unsafe { ERR_GET_LIB_RUST(packed_error) }