From 74a14581164fc2e1700143ad1be06086e64414ae Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pierre-Cl=C3=A9ment=20Tosi?= <ptosi@google.com>
Date: Fri, 9 Dec 2022 18:49:29 +0000
Subject: [PATCH] Introduce minimal static libc for baremetal Rust

LLVM/rustc compiling no_std code expects a few libc symbols to be
defined (memcpy, memset, memcmp). Previously, we used the arm64 library
directly; instead, make the dependency arch-agnostic by exporting it
from Bionic, making it easier to add more libc functions (that might not
be implemented by the optimized routines), as necessary.

Test: m pvmfw_bin && atest vmbase_example.integration_test
Change-Id: I1d2cc69a25bbb7eddc67357a028b7b79d4909e79
---
 libc/Android.bp | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/libc/Android.bp b/libc/Android.bp
index 82fc0bcac..32d48f715 100644
--- a/libc/Android.bp
+++ b/libc/Android.bp
@@ -2261,6 +2261,37 @@ cc_library_static {
     defaults: ["crt_and_memtag_defaults"],
 }
 
+// ========================================================
+// libc dependencies for baremetal Rust projects.
+// ========================================================
+
+cc_defaults {
+    name: "librust_baremetal_defaults",
+    header_libs: ["libc_headers"],
+    include_dirs: [
+        "bionic/libc/async_safe/include",
+        "bionic/libc/platform",
+    ],
+    cflags: [
+        "-Wall",
+        "-Werror",
+    ],
+    system_shared_libs: [],
+    nocrt: true,
+    stl: "none",
+}
+
+cc_library_static {
+    name: "librust_baremetal",
+    defaults: ["librust_baremetal_defaults"],
+    whole_static_libs: [
+        "libarm-optimized-routines-mem",
+    ],
+    visibility: [
+        "//packages/modules/Virtualization/vmbase",
+    ],
+}
+
 // ========================================================
 // NDK headers.
 // ========================================================